ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 148

Palaeontological Society of Japan
December 30. 1987

Co-Editors

Hisayoshi IGO and Tsunemasa SAITO

Officers for 1987- 1988
President : Tatsuaki KIMURA
Honorary President: Teiichi KOBA YASH I
Councillors: Kiyotaka CHINZEI , Takashi HAMADA , Yoshikazu HASEGAWA , Itaru HAYAMI ,Hisayoshi IGO, Junji ITOIGAWA, Tadao KAMEl , Tatsuaki KIMURA, Tamio KOTAKA,Kei MaRl, lkuwo OBATA , Tsunemasa SAITO , Yokichi TAKAYANAGI , Kazushige
TANABE, Toshimasa TANAIMembers of Standing Committee : Kiyotaka CHINZEI (Membership), Takashi HAMADA (Foreign Affairs), Itarn HAYAMI (Finance), Hisayoshi IGO (Co-Editor of Transactions),
Ikuwo OBATA (General Affairs), Sumio SAKAGAMI (Co-Editor of Special Paper),Kazushige TANABE (Planning), Yokichi TAKAYANAGI (Editor of "Fossils"), Juichi
YANAGIDA (Co-Editor ()f Special Paper)
Secretaries: Katsumi ABE (planning), Takeshi ISHIBASHI (Special Paper), Kunihiro ISHIZAKI("Fossils"), Tomoki KASE (General Affairs and Membership), Hiroshi NODA (Editorof Transactions), Terufumi OHNO (Membership), Tatsuo On (Planning), Kazuhiko
UEMURA (General Affairs), Toshiyuki YAMAGUCHI (Finance)
Auditor : Noriyuki IKEYAThe fossil on the cover is Vicarya yokoyamai Takeyama, an Early Middle
Miocene gastropod from the Kurosedani Formation at Kakehata, Yatsuo-cho,
Nei-gun, Toyama Prefecture, central Japan (Collected by T. ,Kotaka and K.
Ogasawara, IGPS No. 99075, photo by S. Ohtomo and Y. Kikuchi, xO.9).

All communication relating to this journal should be addressed to the
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Trans. Proc. Palaeont. Soc. Japan, N.S., No. 148, pp. 197-222,10 Figs., December 30,1987

840. THE OSTRACOD GENUS CYTHERE O.F. MULLER, 1785
AND ITS SPECIES*AKIRA TSUKAGOSHI
Geoiogicallnstitute, University of Tokyo, Tokyo 113
andNORIYUKI IKEYA
Institute of Geosciences, Shizuoka University, Shizuoka 422

Abstract. It has been determined that a total of 17 species in the world belong to thegenus Cythere s.s. All of these species occur exclusively in the coastal areas of the northwestern and northeastern Pacific and the North Atlantic. The genus is restricted to areas northof the Tropic of Cancer. Cythere species are most diverse around the Japanese Archipelago andneighbouring areas. Cythere first appears in the Miocene, and a total of 12 species, including 9
Recent ones, have been found so far in and around the Japanese Archipelago. On the other
hand, only 4 species are found in the northeastern Pacific and only 2 along the northern Atlantic coastal areas. The northeastern Pacific and Atlantic forms are all found in Pliocene or
younger deposits.
The Cythere species are classified into five species groups on the basis of morphologicalcharacteristics. We hypothesize that these groups have been formed in the process of speciation. Members of a group have closer affinities with each other than with a members of any
other group. We have re-examined ten species which are already known to science, and we
describe 7 new species. The new taxa are C. cronini, C. hanaii, C. kamikoaniensis, C. nopporoensis, C. sanrikuensis, C. valentinei, and an unnamed species.

couver Island, British Columbia as C. lutea. On
the basis of the same material in 1952, she proposed two new species C. alveolivalva and C.
uneifalcata (the latter we believe to be a juvenile
of C. alveolivalva). Benson (1959), also describeda Recent Cythere species as Haplocytheridea
maia from Todos Santos Bay, Baja California,
Mexico. In the same year, Hanai (1959) proposed a new species C. japonica (not included in
Cythere in this paper) and two subspecies, C.
lutea uranipponit:a and C. lutea omotenipponica.,from Pliocene and Recent material of Japan,
and redefined the concept of the genus Cythere,
restricting it to the taxa that are closely related
to C. lutea, the type species. Schomikov (1974)
proposed three new species, C. golikovi, C. urupensis, and C. boreokurila, from the littoral zonesof the Kuril Islands, and he also promoted one ofIntroduction
The genus Cythere, established by O.F. Muller
in 1785, is the oldest genus of marine ostracods.
Since it was proposed a large number of marine
forms have been included in the genus. In 1889,
Brady and Norman designated C. lutea as thetype species of the genus Cythere. Most species
which were once included in the genus Cythere
have been transferred to other genera. At present
in the North Atlantic, only C. lutea of the many
species assigned by early workers to Cythere hasremained in the genus Cythere sensu stricto.
In 1931, Lucas, who also published under her
married name, Smith (1952), identified a variety
of forms of living Cythere species from Van*Received August 7, 1987; read February 2, 1986 at
Tohoku University.

197

198

Akira TSUKAGOSHI and Noriyuki IKEYA

the Hanai's subspecies to a distinct species, C.
uranipponica. In the next year (Schornikov,
1975), he raised the other subspecies, C. lutea
omotenipponica, to a species. Okubo (1976) reported C. nishinipponica from littoral zones in
the Inland Sea of Japan, while Valentine (1976)
reported C. maia (= C. sp. in this paper) and C.
sp. B (= C. valentinei, n. sp.) from the Holocene(subfossil) sediments in the areas from Oregon to
California. Hu (1977), in addition, described C.
simplex (= C. omotenipponica ofMalz and Ikeya,
1983) from the Pliocene sediments of Taiwan.
Therefore, through the research of a numberof workers, new members were slowly added to
the genus Cythere since it was first proposed
more than two centuries ago. The distribution ofCythere is known to range from the North Pacificand the North Atlantic Oceans. The list of thespecies belonging to the genus Cythere up to
the present study included only one valid species
from the North Atlantic, two in the northeastern
Pacific, and seven in the northwestern Pacific. In
this report, we reorganize and redescribe theseknown species and, in addition, propose seven
new species: C. cronini from the late Pleistoceneof Northeast America, C. valentinei and C. sp.
from the Pliocene to Recent of the west coast of
America, and C. hanaii, C. kamikoaniensis, C.
nopporoensis and C. sanrikuensis from the
Miocene to Recent of Japan.
The 17 species that constitute the genus
Cythere are described and classified into 5 groups
which seem to suggest close affinities between
the included species as based on the characteristics of the surface ornamentation of the carapace.
The most important characters are the ridges,
pits and the distribution patterns of the sievetype normal pore canals. The principal aim of
this paper is to reorganize the systematics of thegenus Cythere and establish the taxonomic
significance of each species. The description ofthese species is a prerequisite for understanding
speciation and evolutionary patterns in the
Cythere group.
The following abbreviations are used in thispaper.
M: male, F: female, C: carapace, RV: rightvalve, LV: left valve, L: length of valve, H: height
ofvalve,)(: arithmetic mean, OR: observed range,
N: number of specimens.
Carapace morphology of Cythere
Carapace. Valves heavily calcified. Generally
very thick and hard, although some difference isseen between species. Light brown in color when
alive.
Outline. Viewed dorsally, somewhat compressed elongate-ovate, thickest posteriorly, anRR

Hm:

51

aE

mE

RP

PE

lOa pmFigure 1. The terms used in the description of
the surface features of the carapace in the Cytheridae.
a) External ornament of RV in C. valentinei, n. sp.
NP1: normal pores of sieve-type, NP2: normal poresof funnel type, NP3: normal pores of simple type,
Pt: pits, RR: radial ridges, VR: ventral ridgesb) Internal structure of RV in C. valentinei, n. sp.
Hm: hingement, aE: anterior elements, mE: middle
elements, pE: posterior elements, Sl: selvage, RP:radial pores, DS: dorsal scars, FS: frontal scars, MS:
mandibular scars, AS: adductor scars, VS: ventral
scars

840. Ostracod genus Cythere and its species
terior narrower than posterior, both ends birdbill shaped and pointed. LV projects over RV.
RV overlaps LV in the hingement area, which is
the reverse in the ventral view. Viewed anteriorly
and posteriorly, ovate, thickest in the middle.
RV overlaps LV in the dorsal margin. In thelateral view, LV broad bean-shaped, RV subtrapezoidal. Dorsal margin gently arched; more
expensive and gently arched in LV. Ventral
margin slightly sinuate, more pronouncedly in
RV. Anterior margin shows smooth infracurvature, which crosses the dorsal margin at a relatively gentle angle in RV. Posterior margin has
a slight angle in the middle; the lower half gently
curved and the upper half more linear, especiallyinRV.
Ornamentation. Generally not many undulations seen on the surface. A weak ridge runs
along the ventral region of both valves. In somespecies this ridge branches into two in the posterior portion. Several blunt radial ridges are developed; expensive intra- and inter-specific variations found in the degree of their development.
Numerous small, shallow, circular pits distributed
all over the carapace surface; in a few species,
however, these pits are restricted to the ventral
area. Pits generally larger in the central area ofthe valve and smaller in the marginal areas, except for the dorsal margin. The diameter of thepits between 1 to 8 J.l.m. Pits are distributed lessdensely in the center, more densely in the marginal areas. Eye spots very weak by developed.
Size. The adult carapace measures approximately 0.55-0.85 mm in length, 0.35-0.45 mm
in height, 0.31-0.34mm in width. LV larger
than RV in length; the reverse in height.
Sexual dimorphism. Length generally greaterin males than in females, whereas the height of
the two both sexes is about the same. In lateralview, the dorsal and ventral margins curved moregently in male than in female. In the posterior
half of male, a prominent swelling observed
around the postero-dorsal margin, althoughalmost no difference is seen in width between
the two sexes.
Nonnal pores. Single and sieve-types. The
former is further classified into two types; simple

199(without a lip) and funnel (with a lip). Simple
type pores are cone-shaped, the diameter being
2-4 J.l.m at the surface, and the pore opens at
the bottom of the cone. Funnel type pores havea lip with a diameter of 4-6 J.l.m, and the porewith a diameter of about 2 J.l.m opens inside
the lip. Sieve-type pores have a sieve plate with adiameter of 10-20 J.l.m, and the opening at thecarapace surface is cone-shaped. The surface ofthe sieve plate is crowded with a number of small
conical projections. Simple type pores are restricted to the anterior and ventral areas, and thenumber of them is only 5 to 6 per valve. Funnel
type and sieve-type pores are distributed over thevalve, and their numbers are 13 and 60-90 per
valve, respectively. From each pore canal a seta
extends outward, some setae are branched into
two. The location of the pore through which theseta comes out is either in the center or close to
the edge of the plate. The distribution pattern of
the single type pores is fairly stable within thegenus as a whole, whereas that of the sieve-type
pores is consistent at the species level. The distribution patterns of the sieve-type pores clearly
differ among species. Therefore, they are highly
important taxonomic characters in taxonomy. In
this study the distribution pattern of sieve-type
pores on Cythere uranipponica (Figure 2) is used
as a standard to which the other species are compared with each species.
Inner lamella. Marginal areas generally wide,with only a trace of vestibule, widest in the

Figure 2. Distribution pattern of sieve-type normal pores on the RV of C. uranipponica. Combinationof alphabet and arabic numeral shows the reference ofeach pore.

200

Akira TSUKAGOSHI and Noriyuki IKEYA

antero-ventral region, but narrow and twisted in
the middle of ventral margin. Selvage narrow,slightly wider in the posterior margin thananterior margin. A flange is weakly developed at
the posterior end of RV, forming a weak caudal
process.
Radial pores. Distributed mainly in theanteroventral area, numbering 30 to 40 in total.
About half of them short, and do not reach theouter margin. Mostly straight. In the anteroventral area, however, a number of radials areeither bent or slightly sinuous. Not branched.
Somewhat thickened in the middle.
Hingement. Hinge line almost straight. Merodont/entomodont. All the elements are crenulated and arranged in a horizontal plane. In
RV the anterior element forms four rounded
projecting teeth. Two of which at the anterior
end are fused. The median element consists ofabout 30 minute sockets. The posterior element
is similar and symmetrical to the anterior element. LV complementary to RV. The teeth ofthe median element, however, are very fragile
and often not preserved. In the upper part of
the hingement area of the RV a narrow grooveis formed, and above it an eaves-shaped projection is formed in the median element. This projection overlaps the dorsal margin of the LV.
Muscle scars. Four adductor scars are aligned
namely vertically in a gentle curve convex side
to the posterior. The uppermost and the lowest
adductor scars are semicircular, whereas theother two between them both are constricted in
the middle. Frontal scar is a distorted V-shapelocated in front of the upper two adductor scars.
An elliptical mandibular scar in front and below
of the lowest adductor. About 10 dorsal scars arescattered in the upper half of the valve. An
elliptical ventral scar located below and posterior
to the mandibular scar.
Appendages of Cythere
Antennule. Robust. 5-segmented. The lengthof each segment decreases in the following order;
2nd, 1st, 4th, 3rd and 5th segment. 2nd segment
nearly equal to the combined lengths of 3rd and4th segments. Costae develop on the anterior andposterior margins of each segment; especiallybroad in the anterior margin of 2nd, 3rd and 4th
segments. 1st segment without seta, wider thanthe other segments. 2nd segment with plumose
setae on the anterior distal end, the anterior
proximal end and the posterior middle margin;setae in the first 2 areas longer than those in thelast. The anterior margin of 2nd segment covered
with numerous short cilia. Third segment has astout spine on the anterior distal end, and aslightly longer seta with cilia on the posterior
proximal end. 4th segment with a long stout
spines with curved claw-like tips and a short setaon the ledge in the anterior middle, and with aseta on the posterior middle margin. Furthermore, 4th segment has a very strong claw tipped
spine and 3 long setae on the anterior distal end,
and covered with numerous short cilia along theentire anterior margin. On the 2 strong claw
tipped spines of 4th segment numerous serrations are arranged in 2 rows along the anterior
margin. 5th segment with 4 long setae on the
distal end, 2 of them relatively stout.
Antenna. Broad and stout. 4-segmented. The
length of each segment decreases in the following
order; 3rd, 1st, 2nd, and 4th segment. Costae ineach segment well developed and similar to thoseof the antennule. Costae especially broad in theanterior margin of 2nd and 3rd segments. First
segment with short plumose setae on the posterior middle, 1st segment wider than the othersegments. 2nd segment has an very long flagellum
extending from the anterior proximal end to near
the top of the distal claw of 4th segment, andfrom the root of the flagellum extends a plumose
seta. Furthermore, on the posterior distal end of
2nd segment a long stout seta with cilia is developed. Along the anterior margin, 3rd segment
bears a seta or plumose seta on the one fourthfrom the proximal end, and 2 setae of unequal
size on the middle. Along the posterior margin
3rd segment bears 2 stout setae of subequal
size and a fine seta in the middle of the ledge.
Furthermore, a claw develops on the posterior
distal end of 3rd segment. Two terminal claws of
4th segment very well developed, anterior claw

840. Ostracod genus Cythere and its species

201

d

pSL

""

dSL

100 pmFigure 3. Appendages of C. sanrikuensis (Loc. 15. a, b, e-g: IGSU-0-536, c: IGSU-o-553, d, h: IGSU0-542) a): antenule, b): antenna, c): mandibule, d): maxilla, e): first thoracic leg, f): second thoracic leg, g):third thoracic leg, h): copulatory organ (scale: short bar) Cp: capsule, CS: costa, dSL: distal supporting lobe,
pSL: proximal supporting lobe, CA: clasping apparatus, DE: ductus ejaculatorius (ejaculatory duct).

larger than the other.
Mandible. Gnathal lobe beak-shaped on theanterior side with well branched teeth on theposterior side. A palp with 3 segments; 1st segment with poorly developed vibratory plate
bearing a few setae and processes on the distal
part, and 2 long setae on the posterior distal end.
2nd segment with 4 ledges bearing 1 to 6 longsetae respectively, and 2 setae on the distal end,
the anterior seta being especially stout. 3rd segment with 3 stout setae on the distal end.
Maxilla. Branchial plate extremely thin, with
17 long branches along the margin, each branchcovered with numerous cilia. Palp slender, 2segmented. First segment with a somewhat stout
seta on the anterior distal end, and a relatively
fine longer seta on the posterior distal end.

Second segment composed of 3 maticatory processes, each of which bears on the distal end
several stout setae.
Thoracic legs. Three legs similar in shape. 3rdleg longest and 1st shortest. Each leg composedof 4 segments whose length decreases in following order; 1st, 2nd, 3rd, and 4th leg, but 2nd and3rd legs about the same in length. Costae develop
in the anterior and posterior margins of each segment; especially broad in the anterior margin of
2nd and 3rd segments. Many short cilia cover the
distal margins of each segment. Each 1st segment
bears a seta covered with numerous cilia in theproximal, middle, and distal areas of the anterior
margin. Each 2nd segment with a slightly stout
seta on the anterior distal end. 3rd and 4th segments without seta. Each 4th segment bears on

Akira TSUKA GOSH! and Noriyuki [KEYA202

lOOllmFigure 4. Male copulatory organs of Cythere species.
a: C. alveolivalva (Loc. 1, IGSU-O-554), b: C. golikovi (Loc. 16, IGSU-O-555), c: C. lutea (Loc. 6, IGSU-O556), d: C. nishinipponica (Loc. 7, IGSU-O-444), e: C. omotenipponica (Loc. 17, IGSU-O-557), f: C. sanrikuensis (Loc. 15, IGSU-O-542), g: C. schomikovi (Loc. 11, IGSU-O-451), h: C. uranipponica (Loc. 12, IGSU-O433)

the distal end a huge tenninal claw which is equalin length to 2nd segment; these claws have a shortplumose seta in the distal half of the anterior
margin. Sexual dimorphism observed in the claw
of3rd leg; longer in male than in female.
Copulatory organ of the male. (Figure 4).
Basal capsule with costae in the margin almost
rounded quadrangular in the entire shape, withcomplex appendages attached in the distal part.
The complex appendages have a pair of long
tongue-like adapters in the distal part. In theright hemipenis, the distal lobe of the right adapter more rounded, and the proximal lobe often
projects posteriorly in a long finger-like process.
The prehensile hooks vary widely in number

from I to 4, and also differ in shape. Ejaculatoryduct relatively short; not longer than the adapters.
Caudal lamella. A small thumb-like process
projects behind the copulatory organ. The process warps dorsally, and bears many setae on theproximal end; the setae longer and stouter on thedorsal side than on the ventral.
Species groups of Cythere
Cythere is divided into five groups of specieson the basis of surface ornamentation of thecarapace. They are:(I) C. nishinipponica, C. uranipponica;

840. Ostracod genus Cythere and its species(2) C. hanaii, C. kamikoaniensis, C. nopporoensis(3) C. alveolivalva, C. cronini, C. golikovi, C.
sanrikuensis, C. schomikovi(4) c. boreokurila, C. lutea, C. maia, C.
urupensis, C. valentinei, C. sp.
(5) c. omotenipponica(1) Cythere uranipponica group
Several relatively weak radial ridges are developed. Surface of the valve is covered with numerous pits. The number of the sieve-type poreson each valve is approximately 75 to 82. One ofthese pores that is near the center of the dorsal
margin is diagnostic of this group, and is neverseen in other Cythere species. Detailed comparison of the two species of this group is given in
Ikeya and Tsukagoshi (1987).
(2) Cythere kamikoaniensis group
The carapace is thicker and the Height/Length
ratio greater than in other groups. Relatively
distinct radial ridges are developed on the carapace surface, and the ventral ridges are also prominent. Numerous distinct pits are scattered allover the carapace. The number of the sieve-type
pores is approximately 68 to 75, and their distribution pattern is similar to that of C. alveolivalva. The size of the surface pits can be used to
distinction between the species of this group.
(3) Cythere alveolivalva group
The carapace surface is comparatively smooth.
Faint radial ridges, if any, are present in theanterior and posterior areas in some individuals.
Fairly deep pits are found in large numbers in thepostero-ventral area of the valves. However, only
very shallow faint pits or no pits at all are foundin other areas of the valves. The number of thesieve-type pores varies widely; the number isrelatively small (70 to 75) in one subgroup, andrelatively greater (78 to 86) in another. subgroup.
The former includes C. alveolivalva, C. cronini
and C. schomikovi, whereas the latter includes C.
golikovi and C. sanrikuensis. Interspecific variation of the number is smaller in this group thanin others. Distinction between the species, however, is easily made by the distribution pattern of
the sieve-type pores and the copulatory organs.

203(4) Cythere [utea groupDistinct radial ridges develop. The carapace iscovered with deep pits. The number of the sievetype pores is about the same or somewhat lessthan as in the C. uranipponica group. Distinction
between the species of this group is made by the
degree of development of the radial ridges, distribution pattern of the sieve-type pores, andcharacteristics of the copUlatory organs.
(5) Cythere omotenipponica group
The carapace is thick and the Height/Length
ratio is relatively large. Radial ridges are welldeveloped in the posterior half of the valves.
Marginal ridges are developed in the anterior andposterior parts. Gentle swellings exist around thesieve-type pores, and minute shallow pits arepresent on the surface of these swellings. The
number of the sieve-type pores is relatively small(63 to 66). No other species has been found so
far that could be included in this group. What has
been reported reference as this species from
Pleistocene sediments on Chinese coast may be
another species belonging to this group.
Materials and their localities
Listed below are the localities of samples used.
References to locations contained in the text are
indicated by the index number.
Loc. 1: Recent, algal samples collected in July 18,
1940 (provided by T. Hanai). Tidal zone of west coastof San Juan Island, Strait of Georgia, Washington, U.S.A.
Loc. 2: Fossil, 79TC5 sample collected by T.M.
Cronin. "T's" corner (Loc. H-8 of R.B. Mixon), Accomack County, Virginia, U.S.A. (Pleistocene Accomack
Member ofOmar Formation). (see Mixon, 1985).
Loc. 3: Recent, SUT-7-5 sample (well sorted mediumsand) Zostera zone (depth 5m) of Suttsu Bay, Southwest
Hokkaido, Japan (42°46.2'N, 140° 15.8'E).
Loc. 4: Fossil, 840902-5 sample. An exposure along
Hanyu River, about 250m west of Hanyu Village,
Sawane-machi, Sado Island, Japan (37°59.4'N, 138°
15.9'E). (Middle Pleistocene Kaidate Formation).
Loc. 5: Fossil, TG006 sample collected by S. Itoh.
An exposure at the upper most course of Bussha River,about 2.6 km WNW of Kobuchi railroad station of theAniai Line, Kamikoani-mura, Kita-Akita-gun, Akita
Pref., Japan (40 02.5'N, 140 22.6'E). (Late Miocene
Kamikoani Formation).
Loc. 6: Recent, algal samples collected in Nov. 28,
00Akira TSUKAGOSHI and Noriyuki IKEYA

204

1984 (provided by J.W. Neale). Tidal zone of Robin
Hood's Bay, North Yorkshire, England, U.K. (54°26'N,
00° 32'W).
Loc. 7: Recent, algal samples collected in May 11,
1982 (provided by I. Okubo). Tidal zone of Dezaki,
Tamano-shi, Okayama Pref., Setonaikai, Japan (34°30.9'N,133°54.8'E).
Loc. 8: Fossil, Nop. 3 sample. An exposure behindthe "Kyoei" industrial district, about 2.8 km NNW of
Kita-Hiroshima railroad station of the Chitose Line,
Sapporo-gun, central Hokkaido, Japan (43°00.1 'N,
141°33.1 'E), (Late Pleistocene Nopporo Fonnation).
Loc. 9: Recent, St. 2-4 sample (fine to medium sand)collected in May 2, 1983 (provided by H. Kitazato).
Surge channel of tidal zone, Omaezaki, Shizuoka Pref.,Japan (34°35.4 'N, 138° 13.8'E). (see Ikeya et al., 1985).
Loc. 10: Recent, 760808-12 sample (fme sand) collected in Aug. 8, 1976. Tidal zone of Kesaiso , Motoyoshigun, Miyagi Pref., Japan (38° 45.7'N, 141°3l.6'E).
Loc. 11: Recent, algal sample 830807-2 collected inAug. 7, 1983. Tidal zone of Okeneppu, Nemuro Pen.,
Hokkaido, Japan (43° 19.9'N, 145°47.2'E).
Loc. 12: Recent, algal sample 840812-1b collectedin Aug. 12, 1984. Tidal zone of rocky shore, Ayukawahama, Ojika Pen., Miyagi Pref., Japan (38°17.2'N, 140°
30.7'E).
Loc. 13: Recent, 830805-7 sample (medium sand)collected in Aug. 5, 1983. Sand beach of Nosappumisaki, Nemuro Pen., Hokkaido, Japan (43°22.8'N,
145°47.2'E).
Loc. 14: Fossil, 820829-1a sample, Cape Blanco,
Oregon, U.S.A. (42°50.5'N, 124°25.3'W). (Pleistocene,terrace deposits, same as USGS Cenozoic locality M
1450). (see Addicott, 1964).
Loc. 15: Recent, algal sample collected in Jun. 21,
1986. Tidal zone of rocky shore, Toyoura, north coastof Funka Bay, southwest Hokkaido, Japan (42°34.3'N,140° 43.2'E).
Loc. 16: Recent, F 10 sample (silty sand) dredgedby the Sedimentological Research Group of Hokkaido
University. Near shore bottom (depth 5 m) off Kuroiwa,
west coast of Funka Bay, southwest Hokkaido, Japan(42°22.8'N,140 0 20.0'E).
Loc. 17: Recent, algal sample collected in Aug. 17,
1984. Tidal zone of rocky shore, Nagasaki-bana, Choshi,
Chiba Pref., Japan (35°41.1 'N, 139°52.1 'E).

Types
All types of the new species are deposited in
the collection of the Institute of Geosciences,
Faculty of Science, Shizuoka University (IGSUO-number). Duplicate paratypes are depositedin the H.V. Howe Collection, Department of
Geology, Louisiana State University, Baton

Range, Louisiana, U.S.A.
The following abbreviations refer to the institutions where types are preserved:
BLOSJC: Biological Laboratory, Okayama Shujitsu Junior College, Okayama, Japan. UMUT:
University Museum, University of Tokyo, Tokyo,
Japan. USNM: U.S. National Museum of Natural
History, Washington D.C., U.S.A. FESC: Institute of Marine Biology, Far Eastern ScientificCenter, Academy of Science, Vladivostok,
U.S.S.R.
Systematic description
Subclass Ostracoda Latreille, 1802
Order Podocopida G.W. Muller, 1894
Suborder Podocopa Sars, 1866
Superfamily Cytheracea Baird, 1850
Family Cytheridae Baird, 1850
Subfamily Cytherinae Baird, 1850
Genus Cythere O.F. Muller, 1785
Type species. Cythere lutea O.F. Muller, 1785

Cythere alveolivalva Smith, 1952
Figures 4a, 5a, 6-1a, b
Cythere alveolivalva Smith, 1952, p. 23, 24, 26, pI. 4,
figs. 1-10; Schornikov, 1974, p.142, 143, pI. 1, fig. 2,
text-fig. 3; (not) Swain, 1969,p. 462, pl. 4, figs. 12a,b, pI. 7, figs. la, b, pI. 9, figs. 4a, b, pI. 10. figs. 9a,b, pI. 11, fig. 7; (not) Swain and Gilby, 1974, p. 285,
pI. 2, figs. 9,10, 26a, b, Text-fig. 18.
Cythere uncifalcata Smith, 1952, p. 26-28, pl. 5, figs.
1-7. Cythere sp. A. Valentine, 1976, pl. 12, figs. 15,
16.

Types. Syntypes. Female, LV (pI. 4, fig. 2),
L = 0.81 mm; Male, RV (pI. 4, fig. 1) and LV(pI. 4, fig. 3), L = 0.75 mm.
Types. Syntypes. Female, LV (pI. 4, fig. 2),
L = 0.81 mm; Male, RV (pI. 4, fig. 1) and LV(pI. 4, fig. 3), L = 0.75 mm.
Diagnosis. Carapace surface very smooth.However, very shallow pits found in large numbers allover the surface with only a faint ridge in theventral margin. The number of the sieve-type
pores smaller by 5 to 6 in total than that of C.
uranipponica; the pores with the reference
numbers A-3, E-l, E-5, F-2, G-5, and K-l are
missing, whereas a new pore is often added be-840. Ostracod genus Cythere and its species

205•• • eO·•• • • • •• ••••••
0. 0 •••••• • • 0···
•••••

••

·0

•

•

• •••••
• ®.

•

t.·

• .• 0·.....
o. ~ •••
I•••• 0

••

•

•

0 •

•®•••
•••••
••
• • • • ••

.~.

•

••

• ••

®.

• • •• •••.®• • • • • • ••• • •••••• ••• • 0 .
• • ••••. . ·.0·•• • •••••• •• •••

m0·.

• eO • •• • •• • ••• • o· 0·®·o;• •0• ••.

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. ®... .... ....
•. :.
• . .®..• .•
...•
•®

••

®

®

•••

Figure 5. Distribution patterns of the sieve-type pores of Cythere species (In comparison with C. uranipponica, black points: coexisting pores, white circle: missing pores, double circle: additional pores, all figures are
the same magnification).
a: C. alveolivalva, b: C. cronini, c: C. golikovi, d: C. hanaii, e: C. kamikoaniensis, f: C. lutea, g: C. nishinipponica,h. C. nopporoensis, i: C. omotenipponica, j: C. sanrikuensis, k: C. schornikovi, 1: C. uranipponica, m: C. uruppensis, n: C. valentinei

206

Akira TSUKAGOSHI and Noriyuki IKEYA

tween B-2 and C-2 pores. In male, the proximal
lobe of adapters remarkably longer. The two
hemipenises have two pairs of clasping apparatuses; the outer one gently curves inside, and theinner one outside, respectively. Ejaculatory duct
relatively long.
Distribution. Recent: Coastal areas of thenorthern Pacific; northern Kuril Islands, Kamchatka Pen., west of Alaska, and coasts ofWashington, Oregon and California. Fossil: Late
Pleistocene to Holocene terrace deposits from
Oregon to California.
Remarks. The distribution pattern of the sievetype pores very similar to that of C. schornikovi
and C. cronini, but the morphology of the copulatory organ in male greatly differs from that of
C. schornikovi and C. sanrikuensis; C. schornikovi
and C. sanrikuensis have three pairs of clasping
apparatuses on the hemipenis, whereas thisspecies has two pairs. Also the proximal lobe ofadapters longer than that of C. schornikovi, thedifference being particularly marked in the righthemipenis. When Smith (1952) proposed thisspecies, she also recognized C. uncifalcata, n. sp.
as an independent species. However, the clearlyyounger specimen we consider a juvenile form
(A -1 stage) of C. alveolivalva. The word "alveolivalva", which really means "pitted shell", isactually not suitable to characterize this species.
Judging from her comment "surface pitted withapproximately seventy large scattered pits", itseems that she mistook normal pore canals forpits. The number of the sieve-type pores, in fact,corresponds to the number of the "pits" in her
description. From the known geographicaldistribution it is reasonable to assume that thisspecies will be found to inhabit coastal areas of
the Aleutian Islands to Bering Sea.

Cythere boreokurila Schornikov, 1974
Cythere boreokurila Schornikov, 1974, p.14 7-148, pI. 1,
figs. 4a-d, Text-fig. 6.

Type. Holotype, a carapace of male, FESC-No.
353-354.
Type locality. Recent, Kasharot Bay, Paramushir Island.
Diagnosis. Ornamentation of the carapace

generally resembles that of C. uranipponica, but
the radial ridges similar to that of C. urupensis inwhich several ridges are distinctly developed.
Small pits distributed densely all over the carapace except the upper surface of ridges. In males,
the proximal lobe of adapters stout and roundedat the tip. The two hemipenises each have twopairs of clasping apparatuses that are curved
inside; the outer one branches and the inner one
widens in the tip.
Distribution. Recent: Known only from thetype locality; a few living specimens have beenfound (littoral zone of Paramushir Island). It is
probable that this species occurs along the coastsof the Aleutian Islands and Alaska. Fossil: Unknown.
Remarks. This species closely resembles C.
urupensis but differs in morphology of copulatory organs of the male, especially in the clasping
apparatus.

Cythere cronini, n. sp.
Figures Sb, 6-2a-d, 10-3a-c

Types. Holotype, a carapace of male, IGSU-O521 (RV, L = 0.71 mm, H = 0.41 mm; LV,
L =0.69 mm, H =0.41 mm). Paratypes, IGSU-O522 (a carapace of female, RV, L = 0.68 mm,
H = 0.40 mm; LV, L = 0.66 mm, H = 0.40 mm);
IGSU-O-523 (RV of female, L = 0.69 mm, H =0.41 mm); IGSU-O-524 (LV 'of female, L = 0.69mm, H = 0.42 mm).
Type locality. Loc.2.
Etymology. In honour of Dr. T. M. Cronin,
who has provided specimens of this species.
Diagnosis. Closely resembles C. schomikovi inoutline. Carapace surface very smooth, only aweak ridge developed in the ventral margin. No
pits found except in areas along the posteroventral to ventral margin. The number of thesieve-type pores comparatively small (approximately 70 to 75); compared with the distribution
pattern in C. uranipponica, a few pores are
missing, such as E-l, F-2, G-5, K-l, and an additional pore exists between B-2 and C-2, as well as
in C. alveolivalva.
Description. Lateral outline generally bean-

840. Ostracod genus Cythere and its species

Figure 6. (All magnifications x85) Cythere alveolivalva Smith, 1952 (Loc. 1) la. Right lateral view offemale carapace, IGSU-O-519. Left lateral view of female carapace, IGSU-O-520. Cythere cronini , n. sp. (Loc.2)
2a, b . External lateral view of male Rand L valves, holotype, IGSU-O-521 . 2c, d. External lateral view of female
Rand L valves, paratype , IGSU-O-522 . Cythere golikovi Schornikov, 1974 (Loc. 3) 3a. External lateral view offemale RV , IGSU-O-525. 3b. External lateral view of female LV, JGSU-O-526.

207

Akira TSUKAGOSHI and Noriyuki IKEYA

208

shaped, but differs between slightly two valves
and between the two sexes. In the RV the dorsal
margin gently arched, more gently in male thanin female. The dorsal margin joined to the anterior margin at an angle of about 135 0 , and to
the posterior at an angle of about 120 0 • The
posterior margin projects at about the middle
whereas the gentle projection in the anterior
margin is below to middle, this is especially conspicuous in female valves. Carapace surface verysmooth except a weak marginal ridge in theventral and somewhat small deep pits along theposteroventral to ventral area. Faint shallow pits
are sometimes scattered over the surface. The
number of the sieve-type pores approximately 70
to 75. On the sieve plates, the pore throughwhich the seta comes out is located close to theedge of the plate in most specimens.
Dimensions. Listed below are the length andheight measurements of adult specimens fromthe type locality.
HeightLengthRV(M)
RV(F)
LV (M)LV (F)

X

OR

X

OR

N

0.69
0.69
0.72
0.69

0.66-0.72
0.65-0.72
0.70-0.76
0.65-0.74

0.41
0.41
0.42
0.40

0.40-0.42
0.39-0.44
0.40-0.44
0.38-0.43

7
12
3
9

Distribution. Known only from the type
locality.
Remarks. The presence of this species can be
expected from the Pleistocene to Recent at many
localities of the north Atlantic coastal area. Brady(1868, p. 395, 396, pI. 28, figs. 47-56) showed
C. lutea from the coast of U.K. with a smoothsurface as an intraspecific variation. These specimens may be included in this species.

Type. Holotype, a carapace of a male, FESC
No. 355-356.
Type locality. Recent, Iturup Island.
Diagnosis. Height/Length ratio of carapace
smaller than in the other species. Sexual dimorphism in the outline of the carapace not distinct.
A weak ventral ridge develops along the margin
from posteromedian area to the anteroventral
area. Radial ridges and pits are not found on the
carapace surface. Number of the sieve-type pores
between 80 and 86, which is a relatively large
number for the genus. Distribution pattern of thesieve-type pores, compared with that in C. uranipponica: the pores E-I, G-2, K-l are missing, buteight additional pores are found between A-3
and A-4, A-I and B-3, B-2 and C-2, B-2 and C-3,
B-4 and C-6, C-6 and D-7, F-6 and G-9, and G-9
and H-lO, respectively. In male the clasping apparatus more stout and round at the tip than thatof the other species. The two hemipenises havethree pairs of clasping apparatuses; the outerone curves inside and widens in the tip, themiddle one heart-shaped, and the inner one
slender and curves outside.
Distribution. Recent: Only the terminal areaof the "Tsushima Current"; coasts of the south
Kuril Islands, coast of Hokkaido. Fossil: PiloPleistocene formations of northern Honshu to
Hokkaido, Japan.
Remarks. Cythere species generally inhabit
the short algae growing in the tidal zones ofrocky coasts, but Schornikov (1974) reported
that this species was collected on Phyl/ospadixsp., which often grows more than 50 cm inlength. This suggests that this species differs
ecologically from other Cythere species.
Cythere hanaii, n. sp.

Cythere golikovi Schornikov, 1974

Figures 5d, 7-1a- d

Figures 4a, 5c, 6-3a, b

Types. Holotype, RV of male, IGSU-0-527(L = 0.72 mm, H = 0.44 mm). Paratypes, IGSU0-528 (LV of male, L = 0.70 mm, H = 0.42 mm);
IGSU-0-529 (RV, of female, L = 0.68 mm, H =0.43 mm); IGSU-0-530 (LV, of female, L =0.72 mm, H =0.45 mm).

Cythere golikovi Schomikov, 1974, p. 141, 142, textfig. 2.
Cythere lutea lutea: Ishizaki, 1971, p. 77, pI. 2, fig. 12.
Cythere lutea uranipponica: Ishizaki and Matoba, 1985,
pI. 2, fig. 20.

840. Ostracod genus Cythere and its species

209

Figure 7. (All magnifications x85) Cythere hanaii. n. sp. (Lac. 4) la. External lateral view of male RV,
holotype, JGSU-O-527 . lb. External lateral view of male LV, paratype, JGSU-O -528 . Ie. External lateral viewof female RV , paratype, IGSU-O-529 . ld . External lateral view of female LV, paratype, JGSU-O-530 . Cythere
kamikoaniensis, n. sp. (Loc. 5) 2a. External lateral view of male RV, holotype, JGSU-O-531. 2b . External lateralview of male LV, paratype, JGSU-O-532 . 2c. External lateral view of female RV, paratype, JGSU-O-533. 2d.
External lateral view of female LV, paratype, JGSU-O-5 34 .

Akira TSUKAGOSHI and Noriyuki IKEYA

210

Type locality. Loc.4.
Etymology. In honour of T. Hanai, Emeritus
Professor of the University of Tokyo who provided specimens of this species with a faunal slide
including the topotype of C. uranipponica.
Diagnosis. Carapace well calcified and very
thick. Height relatively large and roundish
laterally. Distinct radial ridges and numerous fineshallow pits develop on the carapace surface. The
number of the sieve-type pores approximately
between 70 and 74. In comparison with the distribution pattern in C. uranipponica there is anadditional pore between F-6 and G-9, while six
pores are not found, namely D-6, E-l, F-2, G-4,
H-4, H-7, and K-l.
Description. Carapace extremely thick. Lateraloutline subreniform; dorsal margin gently arched
in RV, but relatively straight in LV. Ventral
margin scarcely sinuate in both valves. The
Height/Length ratio of the carapace larger thanin other species. Sexual dimorphism in the outline of the carapace not clear. The marginal ridgealong the venter well developed, and connectswith a narrow marginal ridge along the posterior.
Radial ridges relatively distinct, forming fanshaped depressions between them. Numerous
fine pits cover the carapace, these pits are denser
in the marginal areas and have a diameter ofabout 1/10 of that of the sieve plates. Number ofthe sieve-type pores between 70 and 74. On thesieve plates the location of the pore throughwhich the seta comes out is close to the edge ofthe plate.
Dimensions. Listed below are the length andheight measurements of adult specimens fromthe type locality.
Lengthornamentation is relatively large.

Cythere kamikoaniensis, n. sp.
Figures 5e,7-2a-dType. Holotype, RV of male, IGSU-0-531(L = 0.66 mm, H = 0.39 mm). Paratypes, IGSU0-532 (LV of male, L = 0.70 mm, H = 0.42 mm);
IGSU-0-533 (RV of female, L = 0.65 mm H =0.40 mm); IGSU-0-534 (LV of female, L ='0.63mm, H = 0.38 mm).
Type locality. Loc. 5.
Etymology. After "Kamikoani", the name of
the formation where the species was first discovered.
Diagnosis. A strong ridge developed continuously along the margin from posterior to venter.
Many deep pits distributed densely all over the
carapace. The number of the sieve-type pores
between 71 to 75, which is nearly average forthe genus. On the distribution pattern of thesieve-type pores, compared with that in C. uranipponica, the pores D-6, E-l, F-2, G-5 are
missing.
Description. Carapace resembles closely thetype species of the genus, C. lu tea , in outline.
Radial ridges developed distinctly on the carapace surface, especially in the anterior half.
Marginal ridge developed strongly along theposterior to ventral margins, especially in theposterodorsal area. Many deep pits distributedensely all over the carapace, and diameter ofthe pits larger (about 1/2 to 2/3 of diameterof sieve plate) in the central area and smaller(about 1/3 to 1/5 of diameter of sieve plate) in
the marginal areas.

HeightLength

-

RV(M)
RV(F)
LV(M)
LV (F)

X

OR

X

OR

N

0.68
0.67
0.68
0.68

0.63-0.72
0.63-0.71
0.65-0.71
0.63-0.72

0.42
0.42
0.41
0.42

0.38-0.44
0.38-0.45
0.40-0.43
0.39-0.45

19
52
12
37

RV(M)
RV (F)LV(M)
LV (F)Height
-

X

OR

X

OR

N

0.68
0.64
0.70
0.65

0.65-0.70
0.61-0.66

0.40
0.39
0.42
0.39

0.37-0.42
0.38-0.41

45
1
4

0.63-0.68

0.38-0.40

Distribution. Recent: Unknown. Fossil: PlioPleistocene formations of northwest Honshu andsouthwest Hokkaido, Japan.
Remarks. The interspecific variation of surface

Distribution. Known only from the type
locality.

Remarks. This species was collected with C.

840. Ostracod genus Cythere and its species
omotenipponica from the type locality, and thefrequency of adult specimens in the sediment
sample is approximately of the ratio of 2 (C.
kamikoaniensis) to 7 (C. omotenipponica).

Cythere lutea O.F. MiilIer, 1785
Figures 4c, Sf, 8-la, b
Cythere lutea D.F. MUller, 1785, p. 65, pI. 7, figs. 3,4;
Brady, 1868, pl. 28, figs. 47-56, pI. 39, fig. 2; Brady
et al., 1874, p. 148, pI. 3, figs. 1-6; Sars, 1925, p.
167, 168, pI. 77; Blake, 1931, p. 160, 161, figs.
Ib-e; Sylvester-Bradley, 1941, p. 27-33, figs. 1518; Grekoff, 1956, p. 52,53, figs. 209-212; Wagner,
1957, p. 47-49, pl. 18; Pokorny, 1958; p. 259,
Text-fig. 931; Hanai, 1959, p. 411, 412; Van Morkhoven, 1963, p. 101-103, fIgs. 135-138; Hanai,
1970,p. 704, text-figs. SA, B;Ruggieri, 1971, p. 288,
fIg. 2; Neale and Howe, 1975, p. 424, pI. 4, fig. 11;
Siddiqui and Grigg, 1975, p. 377, pl. 1, fIg. 15; Load,
1980, pI. 1, fIg. 14; Cronin, 1981, p. 403, pI. 4, rIgs.
7,8; Siveter, 1982, p. 110, pl. 5, fIg. 9; Malz and
Ikeya, 1983,p. 141, text-figs. 2, 3.

Type. Unknown?
Type locality. Recent, North Atlantic (according to Van Morkhoven, 1963).

Diagnosis. Somewhat blunt radial ridges developed. Numerous deep pits cover allover the
carapace surface; distribution of the pits scatteron the central carapace, dense on the marginalarea, and diameter of the pits larger (about 1/2
to 2/3 of diameter of sieve plate) in the center,smaller (about 1/4 to 1/6 of diameter of sieve
plate) in the margin. The number of the sievetype pores is between 74 and 80; compared with
their distribution pattern in C. uranipponica,
seven additional pores exist between B-3 andB-4, B-5 and C-6, C-6 and D-7, D-8 and F-7, F-6
and G-9, G-l and G-2, 1-3 and 1-4, respectively,
and six pores are missing, E-l, E-5, F -2, G-4,
H-4, and 1-5. In male the clasping apparatus, thetwo hemipenises have two pairs of clasping
apparatuses; the outer one longer, curves inside,and branches into two in the tip, and the inner
one shorter and rounds in the tip.
Distribution. Recent: The coasts of North
Atlantic, with the range of latitude 30° to 70 0 N.
Fossil: Middle to late Pleistocene of Europe andNorth America.
Remarks. In addition to C. cronini proposed211

in this paper, it is quite possible that there areother new species that have been assigned to C.
lutea in the North Atlantic. Elofson (1941) also
reported the ecology of this species and statedthat C. lutea is adapted to· the water temperatures of 0° to 20°C, and the depths 4 to 18 m.
It is not live in salinities less than 10 to 12%0.

Cythere maia (Benson, 1959)
Haplocytheridea maia Benson, 1959, p. 48, pI. 3, figs.
la, b, pI. 9, text-rIgs. 7,9; Benson, 1966, p. 745.
(Not) Cythere maia (Benson, 1959): Valentine, 1976,
pI. 12, figs. 3,6.

Type. Lectotype (LV), USNM 113133 (Benson, 1965).
Type locality. Recent, rocky tide pools of thenorthern side of Todos Santos Bay, Baja California, Mexico.
Diagnosis. Carapace surface very smooth.
Posteroventral margin slightly curved toward theinside in the both valves. The projection of carapace on the middle of posterior margin weaks,
and the duplicature in that area narrower than in
the other species. The sieve-type normal pore
canals distribute with widely spaced prominence.
Distribution. Recent: Known only from the
rocky tide pools and the shallow waters of theTodos Santos Bay, Baja California, Mexico.
Fossils: Unknown.
Remarks. Swain and Gilby (1974, p. 285) regarded Haplocytheridea maia Benson, 1959 as asynonym of Cythere alveolivalva Smith, 1952.
However, the specimen of C. alveolivalva illustrated by Swain and Gilby, and H. maia illustrated
by Benson, show greatly different outline andornamentation from C. alveolivalva s. s. Further,H. maia Benson, 1959 and C. alveolivalva by
Swain and Gilby (1974) do not belong to thesame species. We consider C. alveolivalva of Swain
and Gilby (1974) (= C. maia by Valentine)
belongs to a new species as described in thispaper as C. sp. Furthermore, C. maia of Valentine(1976) differs from Benson's species in having avery different outline of the carapace and by adifferent pattern of ornamentation.
Cythere nishinipponica Okubo, 1976
Figures 4d, 5g, 8-2a, b

212

Akira TSUKAGOSHI and Noriyuki IKEYA

Cythere nishinipponica Okubo, 1976, p. 113-119, figs.
la-m, 2a-h', 3a-m; Malz and Ikeya, 1983, p. 141,
text-figs. 4, 5; Ikeya and Tsukagoshi, 1987, p. 911913, pI. 2, figs. a-n, Text-figs. 7E-H.
Cythere [utea omotenipponica: Ishizaki, 1969, p. 215,
216, pI. 26, fig. 9.
Cythere [utea [utea: Hou et al., 1982, p. 158,159, pI.
71, rigs. 1-3, text-fig. 22.
Cythere sp. Cheong et al., 1987, p. 44, pI. 1, fig. 17.

Type. Holotype (a carapace of a female),
BLOSJC-MO 461.
Type locality. Recent intertidal zone, Ozuchi
Island, Okayama Pref., Japan (34°20.5'N, 133°
55.3'E).
Diagnosis. Outline somewhat quadrate on
both ends of the dorsal margin. Weak radial
ridges developed, as well as strong and relatively
wide marginal ridges from anterodorsal toposteroventral. Carapace surface densely covered
with deep pits. The number and distribution
pattern of the sieve-type pores very similar to
those of C. uranipponica, except that there isone more pore in the ventromedian area. The
two hemipenises of the male have two clasping
apparatuses; one of the clasping apparatuses thin
and almost circular. Ejaculatory duct thin andextremely short.
Distribution. Recent: The southern area of
the Tsushima Current (a branch of the Kuroshio
Current); the Yellow Sea, southern coast of
Korean Peninsula, coast of northern Kyushu to
Hokuriku, and coast of the Inland Sea of Japan.
Fossil: Pleistocene formations of coastal areasof China, Cheju Island, Korea, and Noto Peninsula, Japan.
Remarks. Wide geographical variation is founp
in surface ornamentation. For example, the population in the Inland Sea of Japan has distinct
ridges and pits, whereas that in the Sea of Japan
has faint ridges and shallow pits. Detailed description of this species was given in Ikeya andTsukagoshi (1987).
Cythere nopporoensis, n. sp.
Figures 5h, 8-3a-d, 10-4a-d

Cythere lutea: Okada, 1979, p. 159, fig. 14b, pI. 21,
rigs. 1,4-6.

Type. Holotype, RV of male, IGSU-O-537 (L= 0.65 mm, H = 0.38 mm). Paratypes, IGSU-O538 (LV of male, L = 0.65 mm, H = 0.36 mm);
IGSU-O-539 (RV of female, L = 0.71 mm, H =0.44 mm); IGSU-O-540 (LV of female, L = 0.65mm, H = 0.42 mm).
Type locality. Loc. 8.
Etymology. After "Nopporo", the locationand the formation where the species was first
discovered.
Diagnosis. Resembles C. hanaii in lateraloutline, but height in male smaller than that infemale. Ventral ridge well developed, whereas
radial ridges indistinct. Faint rised reticulatae
found around the sieve-type pores. Deep pits
cover most of the surface. The number of thesieve-type pores is approximately 68 to 75, andthe pores, A-3, E-I, F-2, G-5, and K-1, which
exist in C. uranipponica, are not found in thisspecies.
Description. Strong sexual dimorphism isfound in the carapace morphology. In female,the height greater, the wing-like ventral ridge
overhangs the margin in the posteroventral, andthe upper branch of the ventral ridge develops
strongly, especially in the LV. The pits coverdensely around the sieve-type pores and on themarginal areas of the carapace, but less densely
on the rised reticulations and the marginal ridge.
The diameter of these pits larger (about 1/3 to
1/2 of diameter of sieve plate) in central carapace
and smaller (about 1/4 to 1/10 of diameter ofsieve plate) in the marginal area. The location of
the pore through which the seta comes out iseither in the center or close to the edge of thesieve plate.
Dimensions. Listed below are the length andheight measurements of adult specimens fromthe type locality.
LengthRV(M)
RV (F)LV(M)
LV (F)Height

X

OR

X

OR

N

0.64
0.67
0.66
0.68

0.61-0.69
0.61-0.71
0.63-0.67
0.62-0.71

0.37
0.41
0.38
0.42

0.35-0.39
0.38-0.44
0.36-0.38
0.37-0.45

14
32
10
33

840. Ostracod genus Cythere and its species

Figure 8. (All magnification x85) Cythere lutea O. F . MUller, 1785 (Loc. 6) la, b. External lateral view offemale Rand L valves, JGSU-O-535. Cythere nishinipponica Okubo , 1976 (Loc. 7) 2a, b. External lateral viewof female Rand L valves, JGSU-O-446. Cythere nopporoensis, n. sp . (Loc. 8) 3a. External lateral view of male
RV , holotype, JGSU-O-537 . 3b. External lateral view of male LV, paratype, JGSU-O-538. 3c. External lateralview of female RV, paratype, JGSU-O -5 39. 3d. External lateral view of female LV, paratype. JGSU-O -540.

213

214

Akira TSUKA GOSHl and Noriyuki IKEYA

Distribution. Recent: Unknown. Fossil: PlioPleistocene fonnations of the northwest Honshu
and southwestern Hokkaido, Japan.
Remarks. The "well preserved specimens of
C. lutea", reported by Okada (1979) from the
Anden Fonnation of Oga Pen., correspond to
this species.
Cythere omotenipponica Hanai, 1959
Figures 4e, 5i, 9-1a, b
Cythere lutea omotenipponica Hanai, 1959, p. 413, pi.
28, figS. Sa, b; Ishizaki, 1966, p. 137, pI. 17, figs. 912; Ishizaki, 1968, p. 16, pl. 3, figS. 7, 8; (not)Ishizaki, 1969, p. 215, 216, pl. 26, fig. 9; Hanai,
1970, text-figs. lO~-E, 11A, E, J, 12A, A', 13B,
D, D', F, H, H'; Cai, 1982, pi. 4, fig. 46.
Cythere omotenipponica: Schomikov, 1975, p. 4, 5;
Malz and Ikeya, 1983, p. 137-145, pi. 1, figS. 1-8;
Ikeya et al., 1985, p. 9, tab. 1, p. 16,28, tab. 2, pi.
3, fig. 4.
Cythere lutea: Okada, 1979, p. 159, fig. 14a, pl. 21, fig.
3.
Cythere simplex Hu,1977,p.199-201,Fig.17,Fig.24-16,17,19,20,22,23,25.
Cythere simplexia Hu, 1982, p. 178, 180, pi. 4, figs. 9,11; Hu, 1984, p. 111, pi. 1, figs. 20, 24-27.

Type. Holotype (RV), UMUT-CA 3338.
Paratype (LV), UMUT-CA 3339.
Type locality. Recent beach sand from theshore behind Hayama Imperial Villa, Hayamamachi, Kanagawa Pref., Japan.
Diagnosis. Carapace thick and strong. Dorsal
half laterally trapezoid with the dorsal margin
slightly short and arched. Height/Length ratio
larger than in other species. Radial ridges strong
in the posterior half, whereas weak in the anterior half. Marginal ridges develop well in bothanterior and posterior areas. The carapace surface
entirely uneven, sieve-type pores open withdeeper holes near bottom of the hollows, fineshallow pits distributed densely on the entire
surface of the swellings. Sieve-type pores relatively large in diameter and the number of thesepores smaller than that any other species. In
comparison with the distribution pattern of thesieve-type pores in C. uranipponica, this species
lacks 14 pores with the reference numbers C-3,
C-5, D-4, D-6, E-1, E-5, F-2, G-4, G-5, H-4, H-5,

H-7, 1-4, and J-1. Male has a pair of relatively
stout clasping apparatuses, which are slightly
curved inside. Ejaculatory duct is very long.
Distribution. Recent:. Areas under the influence of warm water Kuroshio Current; coast ofnorthern South China Sea, Taiwan, and Kyushu
to northern Honshu, Japan. Fossil: Miocene toPleistocene fonnations of coastal areas of China,
Taiwan, and the Japanese Islands except Ryukyus
and Hokkaido.
Remarks. No Recent specimens of this species
were found throughout our survey between
Taiwan and the Japanese Islands. We are doing
further research to elucidate the reason for theoccurrence of this species from areas that are
geographically isolated from each other.

Cythere sanrikuensis, n. sp.
Figures 4f, 5j, 9-2a-d

Types. Holotype, RV of male, IGSU-0-543(L = 0.66 mm, H = 0.39 mm). Paratypes IGSU0-544 (LV of male, L = 0.66 mm, H = 0.37 mm);
IGSU-0-545 (RV of feamle, L = 0.63 mm, H =0.38 mm); IGSU-0-546 (LV of female, L = 0.63mm, H = 0.36 mm).
Type locality. Loc. 10.
Etymology. After "Sanriku" coast, a common
name for the northeast coast of Honshu facing
the Pacific Ocean, from which the species isfound in abundance.
Diagnosis. Outline of the carapace closely
resembles that of C. schornikovi and C. cronini.
Carapace surface very smooth. Numerous faintshallow pits cover on the ventral margin. The
number of sieve-type pores between 78 and 84,
relatively large in genus Cythere; compared withthe distribution pattern in C. uranipponica, five
additional pores are found between A-I and B-3,
B-2 and C-3, F-6 and G-9, G-9 and H-10, and
1-6 and J-5, respectively, and the pores D-6, E-1,
and F-2 are not found. In the male the proximal
lobe of adapters relatively long. The two hemipenises have three pairs of clasping apparatuses.
Ejaculatory duct stout and relatively short.
Description. Lateral outline generally broadbean-shaped as in C. cronini, the posterior

840. Ostracod genus Cythere and its species

Figure 9. (All magnifications x85) Cythere omotenipponica Hanai, 1959 (Loc. 9) la, b. External lateralview of female Rand L valves, 1GSU-O-541. Cythere sanrikuensis, n. sp . (Loc. 10) 2a. External lateral view ofmale RV , holotype, IGSU-O-543. 2b. External lateral view of male LV, paratype, IGSU-O-544. 2c. Externallateral view of female RV, paratype, IGSU-O-545. 2d . External lateral view of female LV, paratype, IGSU-O546. Cythere schornikovi Ikeya and Tsukagoshi, 1987 (Loc. 11) 3a, b. External lateral view of female Rand L
valves. 1GSU-O -454. Cythere uranipponica Hanai, 1959 (Loc. 12) 4a, b. External lateral view of female Rand L
valves, IGSU-O-436.

215

Akira TSUKAGOSHI and Noriyuki IKEYA

216

margin projects in the middle part as that of C.
schornikovi. Very weak radial ridges develop
both in the anterior and posterior halves, aventral marginal ridge relatively weak. Carapace
surface very smooth except the posteroventralarea, which is faintly reticulated. Numerous relatively deep pits distributed densely in theventral margin and inside the reticulations in theposteroventral area. Faint shallow pits are scattered over the carapace. The number of sievetype pores fluctuates approximately between
78 and 84. The distribution pattern of sieve-type
pores in the ventromedian area similar to that of
C. golikovi. In male the proximal lobe of adapters
relatively long. The two hemipenises have threepairs of clasping apparatus; the outer one curves
inside and longer, the middle one hammershaped, and the inner one club-shaped and witha globular tip. Ejaculatory duct short and bends
in an S-shape.
Dimensions. Listed below are the length andheight measurements of adult specimens fromthe type locality.
LengthRV(M)
RV (F)LV(M)
LV (F)HeightTypes. Holotype, a carapace of male, IGSU-O453. Paratypes, IGSU-O-451, 452, and 454-457.
Type locality. Loc. 11.
Diagnosis. Carapace surface very smooth with
faint uneven ornamentation; blunt radial ridges
and a marginal ridge in the anteroventral area.
Numerous fine pits cover all over the surface.
Number of sieve-type pores between 70 and 74;
compared with the distribution pattern in C.
uranipponica, the pores A-3, D-6, E-1, F-2, G-5,
and K-1 are not found. In male the proximal lobeof adapters extremely long. The two hemipenises
have two pairs of clasping apparatuses; the outer
Glne gently curves inside, and the inner one outside, respectively. Ejaculatory duct relatively
long.
Distribution. Recent: Coasts from southern
Kuril Islands to eastern Hokkaido. Fossil: Pliocene to Pleistocene formations of northern
Honshu and southwestern Hokkaido, Japan.
Remarks. Detailed description of this species
is given in Ikeya and Tsukagoshi (1987).
Cythere uranipponica Hanai, 1959
Figures 4h, 51, 9-4a, b

X

OR

X

OR

N

0.64
0.61
0.66
0.61

0.60-0.70
0.57-0.64
0.57-0.70
0.55-0.67

0.37
0.36
0.37
0.35

0.35-0.40
0.34-0.38
0.33-0.40
0.31-0.38

22
31
17
18

Distribution. Recent: Only the terminal areaof the "Tsushima Current"; Pacific coast ofnorthern Honshu and southern Hokkaido. Fossil:
Plio-Pleistocene of northeast Honshu to southwestern Hokkaido, Japan.
Remarks. Among the C. alveolivalva group,
this species and C. golikovi are adapted to thewarm water region, whereas other three species
the group live in the cold water region.
Cythere schornikovi Ikeya and Tsukagoshi, 1987
Figures 4g, 5k, 9-3a, b
Cythere uranipponica: Schornikov, 1974, p. 143-145,
text-rig. 4, pl. 1, rigs. la-c.
Cythere schomikovi Ikeya and Tsukagoshi, 1987, p.
913-915, text-figs. 7I-L, pi. 3, figs. a-no

Cythere lutea uranipponica Hanai, 1959, p. 412, 413,
pi. 28, rigs. 2, 6a, b, text-figs. 2a, b;Hanai, 1961,p.
366, text-fig. 9, rigs. 2a, b; Hanai, 1970, p. 704,
text-rigs. 5c, d; Ishizaki and Matoba, 1985, pl. 2, rig.
19, (not) rig. 20.
Cythere lutea: Veno and Hanai, 1965, p. 455, rigs. 4201,2, (not) 3; Hanai, 1970, pi. 107, rig. 6; Okada,
1979, p. 159, Fig. 14c, pl. 21, rigs. 2, 7, 8.
Cythere lutea lutea: Ishizaki, 1966, p. 137, pl. 17, rigs.
1,2.
Cythere uraniponica: (Not) Schornikov, 1974, p. 143145, pl. 1, figs. 1a-c, text-fig. 4; Ikeya and Tsukagoshi, 1987, p. 909-911, pi. I, figs. a-n, text-figs.
2b, 7A-D, SA-F.

Types. Holotype, RV, UMUT-CA 3333. Paratypes, LV and RV, CA 3334-3337.
Type locality. Pliocene Sawane Formation.
The cliff at Mano Bay, Sawane-machi, Sado
Island, Niigata Pref., Japan.
Diagnosis. Outline slightly rounded at bothends of the dorsal margin. Weak radial ridges
developed, as well as narrow marginal ridges in
the anterodorsal and posteroventral regions of

840. Ostracod genus Cythere and its species
the valves. Carapace surface densely covered withsmall shallow pits. The number of the sieve-type
pores averages 78, and fluctuates between 75
and 82. One of these pores which is close to thecenter of the dorsal margin, as in C. nishinipponica, exists in addition to those in other
Cythere species. Each hemipenis of the male has
four clasping apparatuses, the greatest number of
all Cythere species. Proximal lobe of adapters
short, ejaculatory duct very thin and short.
Distribution. Recent: The terminal area of
Tsushima Current (a branch of Kuroshio Current); Coasts of the Sea of Japan from San-in tosouthwestern Hokkaido and Pacific coasts from
Sanriku to southern Hokkaido. Fossil: Miocene
to Pleistocene Formations of Northern Honshu
and Hokkaido, Japan.
Remarks. Surface ornamentation and the distribution pattern of sieve-type pores are similar
to those of C. nishinipponica, but this species isdistinguished by the lack of one pore in theventro-median area. Further the morphology ofthe male copulatory organ is radically different
from that of C. nishinipponica. This species was
described in detail in Ikeya and Tsukagoshi(1987).

Cythere urupensis Schornikov, 1974
Figures 5m, 10-la, b

217

mately between 78 and 84. The distribution
pattern of the sieve-type pores, compared withthat in C. uranipponica, eight additional poresare found between B-3 and B-4, B-5 and C-6,
C-6 and 0-7, C-4 and 0-4, C-5 and 0-6, 0-8
and F-7, F-4 and F-5, F-7 and G-8, J-4 and J-5,
respectively, but eight pores, such as E-1, E-5,
F-2, G-4, H-4, and 1-5 are missing. In male thetwo hemipenises have two pairs of clasping
apparatuses; the outer one larger, curves inside,and branches into two in the tip, and the inner
one sharp-pointed and curved inside.
Distribution. Recent: The southern Kuril
Islands to northeastern Honshu, Japan. Fossil:
Plio-Pleistocene formations of northeast Honshu
to southwestern Hokkaido, Japan.
Remarks. This species closely resembles C.
lutea in the male copUlatory organs and the distribution pattern of sieve-type pores. Nevertheless, the two species greatly differ in themorphology of carapace. Their phylogenetical
relationship may be very close.

Cythere valentinei, n. sp.
Figures 5n, 10-2a-d

Cythere sp. B. Valentine, 1976, pI. 12, figs. 9, 13.
Cythere cf. C. lutea: Swain, 1969, p. 461, pI. 1, fig. 11.
Cythere alveolivalva: Swain, 1969, p. 462, pI. 9, figs. 4a,b.

Cythere lutea: Swain and Gilby, 1974, p. 284, pl. 2, figS.
Cythere urupensis Schornikov, 1974,p. 145-147, pI. 1,
figs. 3a-d, text-fig. 5.

Type. Holotype, a carapace of male, FESC
No.351-352.

Type locality. Urup Island.
Diagnosis. Several wide radial ridges develop
strongly, three of which is especially remarkable
and run vertically near the center of carapace.
These both side ridges convex to the center, themiddle one more distinct in the dorsal half. The
sieve-type pores open at the bottom of the coneshaped depression, and the rised reticulatae developed around the cones. Very deep pits distributed densely over the carapace, except for theupper surface of the ridges and the reticulations.
The number of the sieve-type pores approxi-

7a, b, text-figS. 12a-j.

Type. Holotype, RV of male, IGSU-O-549 (L= 0.64 mm, H = 0.37 mm). Paratypes, IGSU-O-

550 (LV of male, L = 0.65 mm, H = 0.38 mm);
IGSU-O-551 (RV of female, L = 0.64 mm, H =0.40 mm); IGSU-O-552 (LV of female, L = 0.63mm, H = 0.37 mm).
Type locality. Loc. 14.
Etymology. In honour of Dr. P.C. Valentine
who illustrated this species and recognized it
differs from other Cythere species.
Diagnosis. Outline and surface ornamentationof the carapace resemble closely those ofC.lutea.
Pits larger in size and smaller in number. The
number of the sieve-type pores is approximately
between about 60 and 65, and the smallest in
the genus Cythere; compared with the distribu-

Akira TSUKAGOSHI and Noriyuki IKEYA

218

tion pattern of those in e. uranipponica, thefollowing 16 pores, C-3, C-5, D-4, D-6, D-8, E-l,
E4,N,~,~4,G4,H4,m,~,M,md

K-l are missing.

Description. In the male Height/Length ratio
and curvature in the dorsal margin smaller thanthose in female. Several wide radial ridges develop, among which the ridges in the posteroventral region form an arc toward the posteroventral margin and continue to the ventral ridge.
The upper branch of the ventral marginal ridge
develops strongly. The marginal ridges at theanterodorsal and the posterodorsal regions also
remarkable. The Numerous deep pits cover the
carapace surface; they are smaller and denser on
the marginal region, and larger and sporadic on
the central region of the carapace.
Dimensions. Listed below are the length andheight measurements of adult specimens fromthe type locality.
LengthRV (M)RV (F)LV (M)LV (F)

x

OR

0.64
0.63
0.66
0.63

0.60-0.65
0.60-0.66
0.64-0.68
0.58-0.67

Height

0.38
0.39
0.38
0.37

OR

N

0.37-0.40
0.36-0.41
0.37-0.39
0.33-0.39

9
11
8
10

Distribution. Recent: Living specimens unknown, but Holocene (sub fossils) from the west
coast of North America; the coastal area of thesouthern Canada to California. Fossil: Pleistocene
to early Pliocene formations of the west coast of
North America.
Remarks. According to Valentine (1976) thisspecies occurs in the areas from latitude 38° to
48.5°N of the west coast of North America. As
a trial estimation of the paleo-temperature fromthese data, he assumed that this species adapted
to the water temperature ranging from 7° to

15°C. Although Lucas = Smith (1931,1952) reported e. lutea from the tidal zone of Vancouver, British Columbia, there are no figures in
her reports. Those "e. lutea" are tentatively
included in this new species based on their geographic distribution. Swain and Gilby (1974)
reported C. sp. aff. e. lutea which is obviously
represented by a juvenile specimen of C. maia
or e. valen tinei.

Cythere sp.
Cythere alveolivalva: Swain, 1969, p. 462, pI. 4, fIgs.
12a, b, pI. 7, figs. la, b, pl. 10, figs. 9a, b; Swain and
Gilby, 1974, p. 285, pI. 2, fIgs. 9, 10, 26a, b, textfig. 18.
Cythere sp. aff. C. lutea: Swain and Gilby, 1974, p. 284,
285, pl. 2, figS. 6, 8.
Cythere maia: Valentine, 1976, pl. 12, figs. 3,6.

Distribution. Recent: Tide pool of Point
Piedras Blancas, California. Holocene (subfossils) the west coast of the California to Baja
California, Mexico. Fossil: Early Pleistocene to
middle Pliocene formations of the west coast of
North America.
Remarks. Dorsal margin of the carapace gently
arched and connected with both anterior md
posterior margins at obtuse angle. Several faintradial ridges found, among which the ridges in
the posteroventral region develop strongly, andthe shape resembles closely that of e. valentinein. sp. The marginal ridges at the posterodorsal
and ventral regions distinctly developed. Smalland relatively deep pits cover the carapace; theseare denser in the dorsal half of carapace, andthe diameter of these pits are about 1/4 to
1/6 of diameter of sieve plates in the central
part of the carapace. The number of sieve-type
pores is great (approximately 80) for the genus.
Valentine (1976) identified the specimens (Valentine, 1976, pI. 12, figs. 3 (= USNM 207982), 6""""* Figure 10. Cythere urupensis Schornikov, 1974 (x85) (Loc. 13) la. External lateral view of female RV,
IGSU-O-547. lb. External lateral view of female LV, IGSU-O-548. Cythere valentinei, n. sp. (x85) (Loc. 14)
2a. External lateral view of male RV, holotype, IGSU-O-549. 2b. External lateral view of male LV, paratype,
IGSU-O-550. 2c. External lateral view of female RV, paratype, IGSU-O-551. 2d. External lateral view offemale
LV, paratype, IGSU-O-552. Cythere cronini, n. sp. 3a. Internal lateral view of female RV, IGSU-O-553 (x72).
3b. Internal lateral view of female LV, IGSU-O-554 (x72). 3c. Distribution of the adductor, frontal, and mandibular scars of female RV, IGSU-O-553 (x320, scale shows 100 ~m). Cythere nopporoensis, n. sp. 4. Sieve andfunnel type normal pore canals of female RV, paratype, IGSU-O-539 (x720, scale shows 10 ~m).

840. Ostracod genus Cythere and its species

219

220

Akira TSUKAGOSHI and Noriyuki IKEYA(= USNM 207983)), collected from a tide pool at
Point Piedras Blancas, California (35°40'N, 121°15'W) as C. maia (Benson). So far as judged fromthe illustrated specimens and descriptions, thesurface of the carapace of H. maia by Benson(1959) appears to be very smooth, whereas thatof C. maia of Valentine (1976) has well developed ornamentation. We consider that C. maia
(Benson), as identified by Valentine (1976)
differs from H. maia Benson, 1959 and belongs
to a new species. According to Valentine (1976)
this species inhabits the area of latitude 26° 45N
to 35°45'N of the water temperature 12° to
24°C in the westcoast of North America. We
include H. maia Benson in the genus Cythere andregard it as an independent species. C. maia of
Valentine (1976) needs a proper new name, but
we need more specimens to fully understand thespecies.
Acknowledgments
This study has been supported by the generous help of numerous persons. First, we wish to
express our sincere thanks to Emeritus Professor
Tetsuro Hanai (University of Tokyo) for his
invaluable advice and continuous encouragement.
His comprehensive knowledge on cytherids including the discovery of the new species fromJapan, has been of great importance to our
research. In the course of this study we received
much invaluable information and many suggestions from the following scientists, to whom
we are also greatly indebted: Professor Joseph
E. Hazel (Louisiana State University), Professor John W. Neale (Hull University), Dr. Heinz
Malz (Forschungs-Institiit Senckenberg), and Dr.
Thomas M. Cronin (U.S. Geological Survey).
Most of the materials used here and comparedwith the study were donated by the following
persons, without whose kind cooperation thiswork could never have been completed: Profs.
T. Hanai and J.W. Neale, Drs. T.M. Cronin,
E.M. Brouwers (U.S. Geological Survey), E.I.
Schornikov (Academy of Sciences, Vladivostok),
A.R. Lord (University College London), D.J.
Horne (City of London Polytechnic), J.E.

Whittaker (British Museum), K.-L. Choe (Korea
Institute of Energy and Resources), I. Okubo(Okayama Shujitsu University), Y. Iwasaki(Kumamoto University), H. Kitazato (Shizuoka
University), T. Kamiya (Kanazawa University),
K. Hayashi (Fussa High School), and S. Itoh
(Kanaya High School). Deep appreciations are
due to Professor J .E. Hazel, Dr. T.M. Cronin andProfessor I. Hayami (University of Tokyo) for
reading the final draft of this manuscript. Financial support for this study was in part from theGrant-in-Aid for Scientific Research in 1984 and1985 (project no. 59440006) from the Ministryof Education, Science and Culture, the Government of Japan.
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--(1968): Ostracodes from Uranouchi Bay, Kochi
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--(1969): Ostracodes from Shinjiko and Nakanoumi,
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ostracods from the Sandnes Clay, Norway. Geol.
Mag., 117 (3), p. 227-242, 3 pls., 3 figS., 2 tabls.
Lucas, V. Z. (1931): Some Ostracoda of Vancouver
Island region. Contr. Can. Bioi. and Fish., 6, p.
399-410,6 pIs.
Malz, H. and Ikeya, N. (1983): Evidence for Japanese
Cythere omotenipponica in Taiwan. Senckenbergiana Bioi., vol. 63, 1-2, p. 137-145,5 text-figs.,
1 pI.
Mixon R. B. (1985): Stratigraphic and geomorphic
framework of uppermost Cenozoic deposits in thesouthern Delmarva Peninsula, Virginia and Maryland. U. S. Geol. Surv., Prof. Paper, 1067-6.
MUller, O. F. (1785): Entomostraca, seu insecta testacea,
quae in aguis Daniae et Norvegiae reperit, descipsit,
et iconibus illustravit. Lipsiae et Havniae, 135 pp.,
21 pIs.
Neale, J. W. and Howe, H. V. (1975): The marine
Ostracoda of Russian harbour, Novaya Zemlya andother high latitude faunas. Bull. American Paleont.,
vol. 65, p. 381-417,10 text-figs.
Okada, Y. (1979): Stratigraphy and Ostracoda from lateCenozoic strata of the Oga Peninsula, Akita Prefecture. Trans. Proc. Paleont. Soc., Japan, N. S. No.
115, p. 143-173, pIs. 21-23.
Okubo, I. (1976): Cythere nishinipponica sp. nov. in the
Inland Sea, Japan. Res. Bull. Shujitsu Junior Coli.,6, p. 113-119, Okayama.
Pokorny, V. (1958): Grundzuge der zoologischen Mikropalaeontologie. Band II. VEB deutsch. Verlag.
Wiss., Berlin, 453 pp.
Ruggieri, G. (1971): Ostracoda as cold climate indicators in the Italian Quaternary. Bull. Centre Rech.
Pau -8NPA 5 suppl., p. 285-293,3 figS.
Sars, G. O. (1925): An account of the Crustacea of
Norway.9,partsl-16,p.I-277, 119 pis., Bergen.
Schornikov, E. I. (1974): On the study of Ostracoda(Crustacea) from the intertidal zone of the KurU
Islands. Trans. A cad. Sci., USSR, Far East Sci.,
Center, Inst. Marine Bioi., no. 1, p. 137-214, 4
pIs., 43 text-figs. (in Russian).
- - (1975): Ostracod fauna of the intertidal zone in
the vicinity of the Seto Marine Biological laboratory.Publ. Seto Marine Bioi. Lab., p. 1-30.
Siddiqui, Q. A. and Grigg, U. M. (1975): A preliminary
survey of the ostracodes of Halifax Inlet. Bull.
American Paleont., vol. 65, p. 369-417, 10 textfigs., 6 tab Is.
Siveter, D. J. (1982): Casts illustrating fme ornament of
a Silurian ostracod. In. Bate R. H. et al., (eds.);
Fossil and Recent ostracods. Ellis Horwood Ltd.,

222

Akira TSUKA GOSHI and Noriyuki [KEYA

p.l05-122.
Smith, V. Z. (1952): Further Ostracoda of Vancouver
Island Region. Jour. Fish. Res., Bd. Can., 9 (1), p.
16-41,11 pis.
Swain, F. M. (1969): Taxonomy and ecology of nearshore Ostracoda from the Pacific coast of North
and Central America. In. Neale, J. W. (ed.). The
taxonomy, morphology and ecology of Recent
Ostracoda. Oliver and Boyd., p. 423-474, 11 pis.,
26 text-figs., 2 tabls.
--and Gilby, J. M. (1974): Marine Holocene Ostracoda from the Pacific coast of North and Central
America. Micropaleontology, vol. 20, no. 3, p.
257-352,7 pis.
Sylvester-Bradley, P. C. (1941): The shell structure of
the Ostracoda and its application to their paleontological investigation. Ann. Mag. Nat. Hist., ser. 11,

vol. 8, p. 1-33.
Ueno, M. and Hanai, T. (1965): Ostracoda. In. Okada,K. et al., (eds.). New illustrated encyclopedia of.
the fauna of Japan. vol. II. Hokuryukan, Tokyo, p.
453-456,2 figS. (in Japanese).
Valentine, P. C. (1976): Zoogeography of Holocene
Ostracoda off Western North America and paleoclimatic implications. U. S. Geo!. Surv., Prof. Pap.,
916,p.I-45, 14 pis., 19 figS., 7 tabls.
Van Morkhoven, F. P. C. M. (1962-1963): PostPaleozoic Ostracoda, their morphology, taxonomy
and economic use. I and II. 204 and 478 pp.
Elsevier Pub!. Co., Amsterdam.
Wagner, C. W. (1957): Sur les ostracodes du Quatemaire
recent des Pay-Bas et leur utilisation dans l'etude
geologique des dept)ts Holocenes. Mouton et Co.,
The Hauge. p. 1-259,50 pis., 21 figs.

Suttu 1if~, Hanyu :fJ=1=., Sa wane tR.m, Sado 1ti:i1t, Kaidate JUl:, Bussha {M±, Kobuchi Ij'
tIlIl, Aniai ~t:il-, Kamikoani 1:./j'~t:, Dezaki lli~, Kita-hiroshima ~tJA iii; , Kesaiso A,tJlit,
Motoyoshi **, Okeneppu ¥'tPm/lftl, Ayukawahama .MII~, Nosappu-misaki ~i?P;(P~IjI. Toyoura
tlrm, Funka bay 1!l!t;kr.1i, Kuroiwa ~!fi, Nagasakibana :lltilllli., Choshi ~tT.

1l'ifj!R Cythere (0. F. MUller, 1785) ~c.:tI7)~I7)~JIi1I:: Cythere~Ii., 17851j:., O. F.
MUller tc J: -:> L tta1=.l7)1l'ifj !Rmtclj-;u).h t.:~15'17) ~ eLL ~ jWj ~ '. *liIf~Ii., :3!: tit:W 17)
Cythere ~17){t{':i:}.; J: rf:mtit~*I7)Mtlit Lt.:JiX..~IT? c;ll<tc, ;:.h i -el7)liIf~~~M L L, *~tc17~iJ~~i.hG ;: c ~§JHJiJ'tc Lt.:. 7.l"ml7)~!\f1 eLL, )i~B9tc1JiF(fttl7)jWj~ ,ifj~l7)o- c":n:';t, Gmt~iIDtclm Q -r G sieve-type normal pore canals 17)7.l";(Pifj~~m~m. L L ~17) 7.l"m~

IT-:>t.:. it.:, :m1=.~tC'?~'LIi., soft part (1=.:1!!lJ1*), *tciltl7)1=.M~1rl7)ifjt~I7).Itt'ltcJ: I),;:.h617)~7.l"~I7)Fa~ttHi~ Lt.:. *jtli., ~t@liW~t).~ttC7.l";(PI!l~ i>~, ~t*i1!i~t&j;j!:J.'I!!~
tc 2~, ~t::tc:lf~:llnmJ.'l!!~tc 4~, B*?UIil;~~tdt;t:lf~i1!i$t&J¥J.'I!!~tc~~~ 3 ~~~tJ12~ (-$~t::tc:lf~:lR$t&j;j!:J.'I!!~cl7);Il<Jm~~~t.,» iJtj£lli-rG. ~17)~~ntli., B*?Ulil;J.'I!!~-e~i>j\iIj<, itdt{':i~~Ii.B*-eIi., 1JJWJ'*'~titi-eJi1j.hGl7)tc~LL,

3 - P ",/~:}';J:rf~t*:lR$-eIi., ,*,WJJ!~titt)'ll*, ~t*i1!i$'15·Ii., ,*,WJff~titt.J.ll*tcj£lli-rG.
LL,*~I7)*~~I7)~~tt~*~L,;:.h617)~~~'W:lJI:c5,?17)~~~-~~~~~~~~10~17)~~.~IT?

c ;Il<tc, 7 ~~ (C. cronini, C. hanaii, C. kamikoaniensis, C. nopporoensis, C. sanrikuensis.
C. ualentinei, C. sp.) HJi!PI[! L, Cythere jtl7)~7.l"{t:}.; J: rfjfg{t**fC~~&'ifJi-r G1:. -e17)~~ c L
t.: ~ '.
~~ !f. il!!~fllJ;z.

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 223-227,3 Figs., December 30,1987

841. ADNA TOCERAS FROM MIDDLE CARBONIFEROUS OF

THE ICHINOTANI FORMATION, FUKUJI DISTRICT, CENTRAL JAPAN*
SHun NIKO and TAKASHI HAMADA
Department of Earth Science and Astronomy, College of Arts and Sciences,
The University of Tokyo, Komaba, Tokyo 153

Abstract. Adnatoceras ichinotaniensis, sp. nov. is described from a late Bashkirian(Middle Carboniferous) limestone of the Ichinotani Formation in the Fukuji district, central
Japan. This species is morphologically characterized by the following features; (1) subcircularcross-section of the shell in early stages, (2) position of the siphuncle shifts ventralwards tosome degree from center as the shell grows, and (3) episeptal-mural and hyposeptal deposits are
well-developed in apical portion. The genus Adnatoceras has previously been known only from
Western Europe, U.S.S.R. and North America of Middle Devonian to Late Carboniferous time.

locality.
The repositories of the described specimens
are in the University Museum, The University ofTokyo (UMUT).

Introduction
The genus Adnatoceras was established by
Flower in 1939 based on Orthoceras spissum
HaIl, the type species for the genus, from theupper limestone band of the Pompey Memberof the Hamilton Group, New York. The genus
has been previously identified from Western
Europe (Ireland; Belgium?), U.S.S.R. (Armenia;
Komi A.S.S.R.: Urals; Kazakhstan; Berkhoyanie)
and North America (Alaska; Texas; Arkansas;
New York). The stratigraphic range of Adnatoceras is known from Middle Devonian throughUpper Carboniferous.
In the present article, we describe a new
species of Adnatoceras from the Ichinotani
Formation in the middle course of the Ichinotani
valley in the Fukuji district, Kamitakara Village,
Yoshiki Country, Gifu Prefecture (Figure 1).
We are deeply grateful to Dr. T. Kobayashi of
the Japan Academy for critical reading of themanuscript. The authors wish to thank Dr. T.
Nishida of Saga University for valuable discussion
and also to Dr. H. Igo of the University ofTsukuba for providing informations of the fossil

x = COLLECTING
SITE

o

1KM

!;;I=====~I*Received August 20, 1987; revised manuscript accepted October 26, 1987; Studies on Japanese Trilobites and Associated Fossils- LVII.

Figure 1. Map showing the fossil locality in the
Fukuji district, Gifu Prefecture.
223

Shuji NIKO and Takashi HAMADA

224

Geological setting
The Ichinotani Formation (late Early Carboniferous to Early Permian age) is exposed in the
Ichinotani valley, Mizuboradani valley, and thelower reaches of the Mizuyagadani valley, andcomprises about 350 m thick of mostly fossiliferous limestone with subordinate amounts ofinterbedded terrigenous sediments. It can be
subdivided into the Lower, Middle and Upper
Members (Igo and Adachi, 1981; Adachi, 1985).
~

~
~

0
Jo.-

oq:
~

The Lower and Upper Members are mostly composed of bioclastic wackestone and packstone;
the Middle Member consists mainly of bioclastic
packstone, wackestone and oolitic grainstone,
and is characterized by frequent intercalation of
red shale and acidic tuff. A detailed descriptionof these rocks is presented by Adachi (1985).
The cephalopod herein described came fromthe upper part of the Lower Member (Figure 2).
The orthoceratid-bearing bed is in a dark graylimestone (bioclastic wackestone) with thin shale,
which contains crinoid fragments, ostracods,
foraminifers, bryozoans, brachiopods, gastropods, goniatites, and rugose corals (Amplexocarinia radicula Igo and Adachi). This bed did
not produce any keen microfauna for age determination except for ill-preserved small archaediscids. However, the occurrence of fusulinid,
Profusulinellafukujiensis Igo, at a part about 3 m
below the orthoceratid-bearing bed may suggestthat it probably corresponds to upper Bashkirian.

ct:
Systematic paleontology

0
LL.

~

oq:
Jo.-

0
~

~

ct:
UJ
~

[ 1m

0

(,)

..,
;:,
;:, LL.
LL.

Family Pseudorthoceratidae
Flower and Caster, 1935
Genus Adnatoceras Flower, 1939

.....

::t

~

I

Superfamily Pseudorthocerataceae
Flower and Caster, 1935

IJ':l:-

I~1[+-, l] 2
~3

-"

1115
;pg,;'.o:6
o o .• ,D,o

FAULT-*

7

Figure 2. Columnar section showing lithology
and stratigraphic position of sample. 1: limestone, 2:
impure limestone, 3: alternating beds of limestone andthin shale, 4: shale, 5: tuffaceous shale, 6: conglomerate,
7: Adnatoceras.

Adnatoceras Flower, 1939, p. 120-121; Balashov
and Zhuravleva, 1962, p. 89; Gordon, 1964, p. 125126; Sweet, 1964, p. K246; Shimanslcy, 1968, p. 78.

Type species:-Orthoceras spissum Hall, 1879.
Diagnosis:-Adnatoceras is applied to smoothorthocone nautiloid with a circular to sub circularcross section being provided with slightly oblique
sutures. Siphunc1e sub central, slightly ventral tocenter. Siphuncular segments are abruptly expanded at the place of septal foramen; parallelsided, and area of adnation equals at least to
width of brim; septal necks cyrtochoanitic tosuborthochoanitic. Both cameral and endosiphuncular deposits are well-developed.
Remarks:-The generic description given aboveis essentially the same as that of Flower (1939),
which is accepted without any emendation. The
morphology of this genus exemplifies the very

841. Adnatoceras from Ichinotani Formation
close relationship to Euloxoceras. The majordifference is in the venterward siphuncular position of the former. Adnatoceras includes species
formerly assigned to Dolorthoceras. The distinction between those two genera is based on the
difference of width of adnation area and expansion of siphunclar segments at septal foramen.
The following Carboniferous species are includedin the genus Adnatoceras:
alaskense Gordon, 1957; Meramecian, Alaska
and Arkansas
ciscoense (Miller, Dunber and Condra), 1933,(Dolorthoceras); Late Pennsylvanian (Cisco),
Texas
ichinotaniensis Niko and Hamada, sp. nov.;
Bashkirian, central Japan (this report)
kipchakense
Shim an sky , 1968; Visean,
Kazakhstan?neglectum (de Koninck), 1880, (Orthoceras);
Tournaisian, Belgium (Flower, 1939; Gordon,
1964)
tyrense Shimansky, 1968; Early Carboniferous, Berkhoyanie
usense Shirnansky, 1968; Visean, Urals
variabile (Foord), 1896, (Orthoceras); Early
Carboniferous, Ireland and Urals

Adnatoceras ichinotaniensis
Niko and Hamada, sp. nov.
Figures 3-1-6

Material:-Holotype, UMUT PM 18068 (Figures 3-1-3, 5); paratype, UMUT PM 18069(Figures 3-4, 6). The studied materials are all theimperfect phragmocones partly replaced bysecondary silicate that the microscopic structures
are often obliterated.
Diagnosis :-Adnatoceras with smooth sheIlsurface, subcircular cross section in early stages
and with relatively shallow septa. ApicaIly, siphuncle sub central with cyrtochoanitic septal
necks; adoraIly it moves to ventral side, andsuborthochoanitic septal necks on ventral side.
Cameral deposits episeptal-mural and hyposeptaI.
Description:-Holotype, UMUT PM 18068:
The holotype is a portion of an orthoconic
phragmocone, 41 mm long. Cross section of the225

shell is sub circular in early stages, later becoming
circular. Diameter of the conch is 4 x 3.5 mm at
the apical end and expands up to 7 mm at theadoral end. The shell surface is smooth. Suturesare straight and slightly oblique to the long axisof the conch. Apically, two and one-half camerae
occupy a length equal to the corresponding
conch diameter; adorally this figure increases tothree and one-half. Curvature of septa is relatively shallow. The siphuncle is sub central inearly stages, slightly ventral side to the center inlater stages. Septal necks are short and cyrtochoanitic, joined by thin rings. Free part of connecting rings is abruptly constricted at septal
foramen, and middle part is almost cylindrical.
Cameral deposits are found throughout thelength of the specimen. On the ventral side of
the siphuncle, it can be differentiated into
episeptal-mural and hyposeptal deposits. Dorsally, L-shaped episeptal-mural deposits aredeveloped in the apical part. The presence of
weak pseudorthoceroid annuli is recognized on
the ventral side of the siphuncle wall in the apical
3 camerae.
Paratype, UMUT PM 18069: This represents
a portion of a phragmocone in more mature
stage than the holotype. Over a length of about
14.5 mm the specimen increases in diameterfrom 7.5 mm to 8.5 mm. Cross section of theshell is circular. About 4 camerae occupy a length
equal to the adoral conch diameter. The siphuncle is circular in cross section and removed
from the center of the conch by a distance approximately euqal to its diameter. Septal necks
are short, suborthochoanitic at the ventral side
and cyrtochoanitic at the dorsal side, joined bythin connecting rings which are abruptly constricted at septal foramen. The shell wall isthicker in the ventral side than in the dorsal side.
No cameral and siphonal deposits are evident.
Discussion :-Adnatoceras ichinotaniensis, sp.
nov. closely resembles A. kipchakense Shimansky
from Kazakhstan, but has more slender shellthan the Russian form. The examined specimens
somewhat resemble A. alaskense Gordon, butthey are different from the latter in having
shorter camerae, shallower septa and non-orna-

226

Shuji NIKO and Takashi HAMADA

Figures 3-1-6 . Adnatoceras ichinotaniensis, sp, nov. 1- 3,5 . UMUT PM 18068 , holotype. 1, ventral view,
x2.2, vertical thin section, apical part , venter on left , x10.3 , vertical thin section, adoral part , venter on left ,x8 .5, cross thin section, near the apical end , venter on down, x 10. 4, 6. UMUT PM 18069 , para type. 4 , verticalthin section, venter on left , x8. 6, enlargement of vertical thin section, venter on left, x18.

841. Adnatoceras from Ichinotani Fonnation
mented shell. A. ichinotaniensis differs in generalfrom A. tyrense Shimansky and A. ciscoense(Miller, Dunbar and Condra) in having more eccentric siphuncle and circular cross section of theshell in later stages. The specimens mark the firstoccurrence of the genus in East Asia.
References
Adachi, S. (1985): Smaller foraminifers of the Ichinotani Formation (Carboniferous-Permian), Hida
Massif, central Japan. Sci. Rep., [nst. Geosci, Univ.
Tsukuba, Sec. B, vol. 6, p. 59-139, pIs. 8-23.
Flower, R. H. (1939): Study of the Pseudorthoceratidae.
Palaeont. Americana, vol. 2, no. 10, p. 1-214, pis.
1-9.
Foord, A. H. (1897-1903): Monograph of the Carboniferous Cephalopoda of Ireland. Palaeont. Soc.
London, Mon., p. 1-234, pIs. 1-49.
Gordon, M., Jr. (1957): Mississippian cephalopods ofnorthern and eastern Alaska. U.S. Geol. Survey
Prof. Paper 283, p. 1-61, pis. 1-6.
- - , (1964): Carboniferous cephalopods of Arkansas.
/bid., 460, p. 1-322, pIs. 1-30.
Igo, H. and Adachi, S. (1981): Foraminiferal biostrati-

227

graphy of the Ichinotani Formation (CarboniferousPermian), Hida Massif, central Japan, Part 1 -Someforaminifers from the upper part of the Lower
Member of the Ichinotani Formation-. Sci. Rep.,[nst. Geosci., Univ. Tsukuba, Sec. B, vol. 2, p.
101-118, pIs. 4-6.
Miller, A. K., Dunbar, C. O. and Condra, G. E. (1933):
The nautiloid cephalopods of the Pennsylvanian
System in the Mid-continent region. Nebraska Geol.
Survey, ser. 2, Bull. 9, p. 1-240, pIs. 1-24.
Ruzhentsev, V. E., Shimansky, V. N., Zhuravleva,
F. A. and Balashov, Z. G. (1962): PY>KeHHeB,
B. E., W.l\MaHCKHH, B. H., )KypaBJleBa, <1>. A. H
BaJlall\OB, 9. r. OCHOBbI naJleOHTOJlOTHH, JIOJlJlIOCKH-rOJlOBOHOTHe 1. HSbamellbCmoo AKaq.
HaYK CCCP MocKoa, CTp. 1-438, TaoJl 1-89.
W.HMaHcKHH, B. H.
Shimansky, V. N. (1968):
KaMeHHoYTOJIbHble Orthoceratide. Oncoceratida,
Actinoceratida H Bactritida. AKall HaYK CCCP,
TpYObl nalleoHm. HHcm., TOJl 117, CTp. 1151, TaoJl. 1-20.
Teichert, C., Kummel, B., Sweet, W. C., Stenzel, H. B.,
Furnish, W. M., Glenister, B. F., Erben, H. K.,
Moore, R. C. and Zeller, D. E. (1964): Treatise on
invertebrate paleontology, Pt. K, Mollusca 3,
Moore, R. C., ed., Geol. Soc. America and Kansas
Univ. Press, p. K1-K519.

Ichinotani - /:fr, Fukuji f'jJt!!, Kamitakara J:~, Yoshiki -al/it, Gifu ilJtlj!., Mizuboradani 7.KilRl:fr, Mizuyagadani 7.K~ 7 :fr.

ilJtlj!.JI1!,f'jJt!!Jt!!l!J!1:, - J :fr1l(l)1'il!R*c<=pM Adnatoceras : ilJtlj!.JI1!,-al/ittt~J:~,fjf'jJt!!Jt!!l!J!1:(l)- J:fr

II (l) r $ II J: $ (late Bashkirian) J: IJ i!Jl. tl:l L.. t::. Adnatoceras ichinotaniensis Niko and
Hamada, sp. nov. ~~11i\t L..t::.. *fili, (l)Rlt~(l)j:t~B'9:mM~.:.jj[P3t'\(l)1&:,*iID~jf-i", (2){;it;'r(l)&1i!i::b~ij\(;:!5H.:. {f~ '1&:(l)<=PIL.':b'i?~~!JI{J!~",~jJi" ~, (3) episeptal-murallitlfhyposeptal (l)~&1i!i:~.:.~mP:l7t~'<1'm:b~~16i?.h~::' c~.:. J: IJ !I'It~-':Ht i?.h ~. Adnatoceras ~Ii, tt*f!§ 3 - I:l '"J{,'J~';r. r, ~t*(l)<=p$T',f-:/ *:b'i?J:$1'i l!R~~H':':b·It-C (l):lj.-t(l)i!Jl.tl:l :b~~ i?.h -C ~ ,t::..

!JC.T~1'f]·~mlli±

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 228-245, 11 Figs., December 30,1987

842. EARLY CARBONIFEROUS CORALS FROMTHE OMI LIMESTONE, CENTRAL JAPAN'"
YASUSHI YOSHIDA, YUH OKIMURA
Institute of Geology and Mineralogy, Faculty of Science,
Hiroshima University, Hiroshima 730
and

MAKOTOKATO
Department of Geology and Mineralogy, Faculty of Science,
Hokkaido University, Sapporo 060

Abstract. Corals are abundant in the lowest part of the Omi Limestone, Central Japan.
An assemblage of corals obtained from the lowest part in the Fukugakuchi area comprises morethan 13 forms, from which the following five species including three new species are herein
described and illustrated: Cyathaxonia cfr. C. cornu Michelin, Clisiophyllum kurohimense, sp.
nov., Akiyosiphyllum stylophorum Yabe and Sugiyama, Carcinophyllum hasegawai, sp. nov.
and Hiroshimaphyllum simplex. sp. nov. This coralline fauna is correlatable with that of the
Nagatophyllum satoi Zone of the Akiyoshi Limestone, Southwest Japan, and indicates Late
Visean in age.

Introduction
The Carboniferous coralline faunas of the Omi
Limestone distributed in Nishikubiki County,
Niigata Prefecture, Central Japan, were describedor reported by Hayasaka (1921, 1922, 1924,
1932, 1939), Kawada (1954a, b, c), Minato(1951,1955), FUjita (1958), Kato et aZ. (1964),
Kato (1967), Rowett and Minato (1968) and
Kato and Minato(1975).
Recently, one of the authors (Y.Y.) newly
collected a number of specimens of corals fromthe lowest part of the Omi Limestone in the
Fukugakuchi area (Figure 1). This locality isreferable to the lower part of the Endothyra
Zone of Hasegawa et al. (1969,1982).
In this paper the fauna is discussed in termsof its affinity, and five species including three
new species are described.

Mt. Kurohime
A 1221.5o!

*Received August 20,1987
Figure 1.
228

Map showing the fossil locality.

2km!

842. Early Carboniferous corals from Omi Limestone
Stratigraphy and age of the coralline fauna
The lowest part of the Omi Limestone is characterized by the greenish or purplish, basic pyroclastic rocks with bioclastic and tuffaceous
limestone clasts of various size, intercalating theoolitic limestone layers near its uppermost part
i

• ~

• I •
I • I
• I •
1 •1

•1 •

I • I
•1 •
I • I
I
I 1
I

rn

rs=g

~

3

B

4

\

m

5

I

(about 14 m in total thickness). The coral specimens were obtained from the uppermost partconsisting of bryozoan-crinoidal packstonerudite
with basic tuffaceous matrices (1.5 m in thickness) followed by massive bioclastic and oolitic
limestone (Figure 2).
The following is a list of identified corals
from the above mentioned locality and horizon(Numerals show the examined specimen-number).
*Cyathaxonia cfr. C. cornu Michelin
8
Neaxon sp.
1
Zaphrentoides spp.
7
"Polycoelia" japonica Ozawa
12
Plerophyllum spp.
2
Pentaphyllum sp.
1*Clisiophyllum kurohimense, sp. nov.
9
*Akiyosiphyllum stylophorum
Yabe and Sugiyama
67*Carcinophyllum hasegawai, sp. nov.
30
*Hiroshimaphyllum simplex, sp. nov.
5
Pseudofavosites sp.
1
Pseudoromingeria kotoi(Yabe and Hayasaka)
9
Metriophyllidae, gen. et sp. indet.
1*Species herein described.

2

IEOCDI 5
6oFigure 2. Columnar section of the lower part of
the Omi Limestone in the Fukugakuchi area, showing
the stratigraphic position of the fossil locality shown on
index map, see Figure 1. 1: oolitic limestone; 2: bioclastic packstone; 3: bryozoan-crinoidal packstone-rudite;
4: basic tuff; 5: clasts of limestone; 6: pyroclastic rocks.

229

Total

153

The coralline fauna, besides, is associated withsuch smaller foraminifers and primitive fusulinaceans as Endothyra spinosa Chernysheva, E.
gigantea (Okimura), E. masanae (Okimura), E.
spp., Globivalvulina sp., Palaeotextularia spp.,
Tetrataxis spp., Endostaffella sp., Mediocris
mediocris (Vissarionova), M. breviscula (Ganelina), and this foraminiferal assemblage is closelyreferred to those of the Middle to Late Visean
Endostaffella delicata Zone and the lower part of
the Mediocris mediocris Zone of the Akiyoshi
Limestone, Southwest Japan (Okimura, 1966).
Two species described in this paper, Cyathaxonia cfr. C. cornu and Akiyosiphyllum stylophorum, and "Polycoelia" japonica, are well known
as the important faunal elements of the Middle
to Late Visean Nagatophyllum satoi Zone of the
Akiyoshi Limestone (Ota, 1977). In addition tothe occurrences of common species between the
Akiyoshi and this area, it is noteworthy that thelithologic characters described by Ota (1977)

Yasushi YOSHIDA, Yuji OK/MURA and Makoto KATO

230

show the close affinity to those in the locality of
Fukugakuchi.
Recently, Tazawa et al. (1983) describedsome Late Visean brachiopod species from basic
tuff in the lowermost part of the Omi Limestone
cropping out in the east side of the Omi River.
Stratigraphically, the brachipod bearing horizon
may be slightly lower than the impure limestone
bed yielding the present corals.
According to the viewpoints mentioned above,
the present authors estimate this coralline fauna
to be of Late Visean age.
Systematic Description
All the specimens described and illustrated in
the present study are stored in the Institute ofGeology and Mineralogy, Faculty of Science,
Hiroshima University, Hiroshima. The registerednumbers of the type specimens (IGSH-YY No.)and the illustrated specimen-numbers (OM No.)are shown in the brackets of explanation of
Figures.
Family Cyathaxoniidae Milne-Edwards andHaime, 1850
Genus Cyathaxonia Michelin, 1847

Type species (by subsequent deSignation ofMilne-Edwards and Haime, 1850):Cyathaxonia cornu Michelin, 1847
Cyathaxonia cfr. C. cornu Michelin

fIg. 5.
1978 Cyathaxonia cornu; Yii et al., p. 14, pl. 1, figs.
lla-b, 12a-b.
1981 Cyathaxonia cornu; Poty, p. 17, pl. 2, fIgS. 2-5.
1986 Cyathaxonia cf. C. cornu; Haikawa, pl. 3, fIgS. 1,
2.

Material:-Eight fragmental corallites, fromwhich twelve thin sections were prepared.
Description:-Corallum is solitary, ceratoid
and small in size. The length of the corallum is
unknown, owing to the lack of its proximal end.
In transverse section, corallite has round andsmooth configuration, and is 3.3 mm in diameterin the largest corallite. The peripheral stereozone
formed by lateral fusion of septa is prominent.
No dissepiments are developed. Septa are thickand in two orders, major and minor respectively.
Fossula is not observed. Major septa are long,reaching a columella. The axial ends of septa arebluntly terminated and occasionally slightly
clavate. Counter septum is somewhat thinnerthan other major septa. Minor septa, which are alittle thinner than and alternate with the major,
show a contratingent nature. They attain usually
1/2 to 2/3 the length of the major, and sometimes they are longer and join the major at the
periphery of the columella. Minor septa on bothsides of the counter septum are longer than therest and may be connected with the columella.
Septal fme structure is trabecular. The sides of
septa are smooth and not vepreculate. As manyas 28 septa occur in the 3.3 mm diameter corallite. Relationship between the number of septa
and the diameter of corallite is shown in Figure

Figures 4-1a-3
Compare:1847 Cyathaxonia cornu Michelin, p. 258, pI. 59, figs.
9a-b.
1909 Cyathaxonia cornu; Faurot, p. 75 (7).
1913 Cyathaxonia cornu; Carruthers, p. 53, pI. 3,figs.
4-7.
1940 Cyathaxonia cornu; Hill, p. 195.
1960 Cyathaxonia cornu; Vassiljuk, p. 157, pI. 12, fig.

8.
1964 Cyathaxonia cornu; Vassiljuk, p. 87, pI. 7, fig. 1.
1968 Cyathaxonia cornu; Fedorowski, p. 210, pI. 1,
figs.4a-d.
1977 Cyathaxonia cornu; Khoa, p. 319, pI. 1, fIgS. 1,2,
3a-b,4-6.
1978 Cyathaxonia cornu; Poty in Kirnpe et al., pI. 5,

mm
CI)

~4

iU
...

83

O

... 2

.... 1
CI)

•

• •

•

•
• •

CI)

E

III

=s

20

25

30

number of septa
Figure 3. Relationship between number of septa
and diameter of corallite in Cyathaxonia cfr. C. cornu
Michelin.

842. Early Carboniferous corals from Omi Limestone
3. Columella is round in outline, occupies 1/5 to
1/3 of the diameter of corallite. In one coraIlite(OM 10003), it merely reaches 1/7 of the diameter. The columella is solid and compact, inwhich calcite fibres are radially arranged fromthe centre. No concentric growth liiles can beseen in the columella.
Only one longitudinal section is available,
which is cut through the centre of the septa sothat the features of tabulae are not observable.
Wall is thick and smooth, as far as preserved.
Columella is wide and stout, with the fibres
directed upwards and outwards from the axis.
Calice is deep, with a distinct calicular boss.
Remarks:-The present form is almost identical with Cyathaxonia cf. C. cornu figured by
Haikawa (1986), which was obtained from the
Visean of Akiyoshi, Southwest Japan. Concentric
growth lines are said to be present in Cyathaxonia cornu (e.g. Carruthers, 1913, p. 54). This
character is not found in the present form.
Cyathaxonia rushiana Vaughan (1906) isclearly distinguished from the present form inhaving larger corallite.
Family Aulophyllidae Dybowski, 1873
Subfamily Clisiophyllinae Nicholson, 1889
Genus Clisiophyllum Dana, 1846

Type species (by subsequent designationof Dingwall, 1926):-Clisiophyllum keyserlingi
McCoy, 1849
Clisiophyllum kurohimense, sp. nov.
Figures 4-4a-6

Derivation of the specific name:-After the
Mt. Kurohime in the Omi district, Niigata Prefecture,Japan.
Material:-Nine solitary corallites, from which
24 transverse and longitudinal sections wereobtained. Holotype IGSH-YY 10001, Paratypes
IGSH-YY 10002-10006.
Specific diagnosis :-Medium sized Clisiophyllum having fairly long minor septa and a weakaxial structure with a long and sinuous medianplate, septal lamellae which tend to degenerate

231

and tent shaped axial tabellae. Caninomorphic
corallites may occur.
Description :-Corallum is solitary, ceratoid,
and medium in size. Surface characters are unknown.
In transverse section, coraIlite is round inoutline, but its peripheral parts are often eroded.
It is 17 mm in diameter in the largest corallite,
and internally consists of wall, dissepimentarium,
tabularium and axial structure. Wall is thin andwith smooth external surface, and no trace forthe presence of ridges or grooves is detectable.
Dissepimentarium is comparatively narrow, occupying 1/4 to 1/3 of the radius of corallite. It
is composed of regularly or irregularly arranged
concentric or angulo-concentric dissepirnents.
Lateral dissepirnents are frequently developed in
the peripheral part. Herringbonal dissepirnents
occur in the places in which minor septa areshort or intermittent. Only occasionally pseudoherringbonal dissepiments are observed between major and minor septa. Lonsdaleoid
dissepiments are absent. Inner wall is indistinct.
The boundary between dissepimentarium andtabularium is not very clear. Tabularium is wide,
where cut edges of tabulae are seen between
septa. Septa are in two orders, major and minor
respectively. They are straight or slightly flexuous, relatively thin, but somewhat thickened in
the tabularium. Major septa are long, extending
towards axial structure, and some of them are intruded in the latter structure. Minor septa alternate with the major septa and are a little thinnerthan the major. They are in general fairly long,protruded into the tabularium, but uncommonly
short, confined in the dissepimentarium. Septal
fine structure is trabecular. The number of major
septa is counted as 39 in a corallite of 16 mm indiameter. Relationship between the number ofmajor septa and the diameter of corallite isshown in Figure 5. Cardinal fossula may bemarked by a slight contraction of dissepimentarium or the shortening of the cardinal septum.
Axial structure is usually large, occupying 1/4 to
1/3 of the diameter of corallite, but is not welldifferentiated from the tabularium. In early
growth stage a complicated axial column is232

Yasushi YOSHIDA, Yuji OK/MURA and Makata KATO

Figure 4. 1- 3 CY.Jthaxonia cfr. C. cornu Michelin , all xlO. la-b. Transverse sections (OM 10001), 2a- c.
Transverse (2a-b) and longitudinal (2c) sections (OM 10002),3. Transverse section (OM 10003). 4- 6. Clisio·phyllum kurohimense , sp . nov., all x3. 4a- d. Longitudinal (4a, 4d) and transverse (4b, 4c) sections (Holotype :IGSH-YY 10001),5 . Serial transverse (5a- b, 5d - e) and longitudinal (5c) sections (Paratype: IGSH-YY 10002),
6. Transverse section (Paratype: IGSH-YY 10003).

842. Early Carboniferous corals from Omi Limestone
mm
20
GI

~
I'CI
...
o

-

u 15

o

...
GI
a; 0

E
I'CI
:0

25

30

35

40

number of major septa
Figure S. Relationship between number of major
septa and diameter of corallite in Clisiophyllum kurohimense, sp. nov.

developed, which is composed of a long medianplate, slightly sinuous, discontinuous and radiallyarranged septal lamellae -approximately equal in
number to the major septa-, and thin, small,numerous and outwardly convex axial tabellae(Figure 4-5a). It is mostly separated from theaxial ends of the major septa, but with someseptal lamellae joined to the major. As thegrowth proceeds the median plate becomesthinner and septal lamellae gradually degenerate(Figure 4-5b). In the mature stages axial structure
is loosely constructed by a thin, long and flexuous median plate which is reinforced by rings ofaxial tabellae, and a few or no septal lamellae(Figures 4-4b-c, -5d-e). Median plate is mostly
connected with the cardinal septum in early
growth stages, but becomes almost separated
from it in the mature stages. Caninomorphs
occur in a few corallites in which no axial structure is present (Figure 4-6).
In longitudinal section, wall is thin and weakly
undulated. Dissepimentarium is comparatively
narrow, with 3 to 6 rows of irregular globose
dissepiments of various size. Dissepiments arelarge and steeply inclined in the periphery andsmall, vertical near the tabularium. Differentiation between the dissepimentarium and tabularium is clear. Tabularium is wide, and is occupied
by incomplete, vesicular and upwardly convex
peripheral tabellae which are steeply ascending

233

towards the axial structure in early growth stage(Figure 4-4a), but more or less horizontallydisposed in the mature stages (Figures 4-4d, 5c).
Axial structure is not well differentiated fromthe tabularium, consists of a thin, sinuous
median plate and tent shaped axial tabellae ascending towards the median plate and resting oneach other on the periphery of the axial structure. A few vesicular tabellae may appear axially.
Remarks:-No previously described species ofClisiophyllum is similar to the present form. The
present form is characterized by fairly longminor septa and a weakly constructed axial structure in which septal lamellae tend to degenerate
and axial tabellae are tent shaped in longitudinal
section. These features serve to distinguish itfrom any other species of the same genus.
Family Lithostrotionidae d'Orbigny, 1852
Subfamily Lithostrotioninae d'Orbigny, 1852
Genus Akiyosiphyllum Yabe andSugiyama, 1942

Type species (by Monotopy):-Akiyosiphyllum stylophorum Yabe and Sugiyama, 1942
Akiyosiphyllum stylophorum Yabe andSugiyama
Figures 7-la-15b

1942 Akiyosiphyllum stylophorum Yabe and Sugiyama, p. 574, figs. 1,2.
1955 Akiyosiphyllum stylophorum; Minato, p. 167, pI.
16, fig. 3; pI. 19, fig. 2; pi. 26, fig. 1 ; pI. 30, fig. 3;
pi. 37, figs. 5a-c.
1986 Akiyosiphyllum stylophorum; Haikawa, pl. 2,
figs.3a-b.

Material:-Sixty-seven coralla, from which
146 thin sections have been prepared and examined.
Description :-Corallum is compound, fasciculate and dendritic. Corallites are cylindrical andsubparallel, closely arranged and are often incontact with each other. Surface characters are
unknown.
In transverse section, corallite has round andcomparatively smooth configuration, and is234

Yasushi YOSHIDA, YujiOKIMURA andMakotoKATO

12.8 mm in diameter in the largest corallite.
Internally it consists of wall, dissepimentarium,
tabularium and axial column. Wall is moderately
thick. In some corallites the peripheral stereozone formed by lateral fusion of septa is present
and already developed even in relatively early
growth stages. It becomes gradually thickened as
the coral grew upward, but is never constantly
developed. In the mature stages it is prominent in
a part of corallite, but indistinct in other part, sothat the thickness of the wall is variable even
within one corallite. The width of the dissepimentarium is narrow to comparatively wide, butless than 1/2 of the radius of corallite, and is frequently so reduced as to be replaced by a thickstereowall. It is composed of regularly or irregularly arranged concentric to angulo-concentric dissepiments when minor septa are welldeveloped. Dissepiments become inosculating toherringbonal in case of weakly developed minor
septa. Lateral dissepiments occur in the periphery of the dissepimentarium in some corallites.
Sometimes, when corallites are relatively large,
dissepiments show pseudoherringbone pattern inthe place between major and minor septa. Only
occasionally, lonsdaleoid dissepiments may be
developed, but they are small and only indicatedby discontinuous minor septa. Intrathecal dilation on the septa and the internal surface of thedissepimentarium may form a distinct inner wall.
The boundary between dissepimentarium andtabularium is clear. Tabularium is wide, where
cut edges of tabulae are seen between septa.
Septa are in two orders, major and minor respectively. Fossula is usually indistinct. Septa arealmost straight, or slightly sinuous in the dissepimentarium. Major septa are long, extend towards
axial column and directly unite with it in early
growth stages, but become separated from it in
the mature stages in some corallites. They are
more or less dilated in the tabularium, but attenuated in the dissepimentarium. However, insome corallites some of them may be very thickat their bases, forming a stereozone as above
stated, and rapidly attenuating towards axis. The
axial ends of major septa are sharply tapering or
bluntly terminated, and often slightly clavate.

Minor septa alternate with the major, and extremely variable in length. They are fairly long,
intruding into the tabularium in some corallites,but very short, confined in the dissepimentariumin the others. Septa are in general radially arranged, but show somewhat pinnate arrangement
when some short major septa are newly inserted.
Fine structure of septa is trabecular. As manyas 29 major septa are counted in the 11.5 mm
diameter corallite. Relationship between thenumber of major septa and the diameter ofcorallite is shown in Figure 6. Axial column islarge, variable in size and construction, and its
morphologic'al and ontogenetic trends correspond to the series from type a to type d ofKato (1963, text-fig. 18). In very early growthstages it is represented by a elongation of the
cardinal septum, with which the axial ends ofother major septa are confluent (Figure 7 -6). Subsequently, it is dilated to form a round, solidand compact columella, in which calcite fibres
are radially arranged around a median plate incounter-cardinal plane (Figures 7-la, 3a-c).
With the growth, the columella becomes split
into bundles by grouping of calcite fibres to form
contiguous septal lamellae which correspond toboth major and minor septa, showing an appearance of typical amygdalophylloid axial
column (Figure 7-1 b). In some corallites such acolumn still presists or is only sporadically replaced by a few axial tabellae even in the mature
stages (Figures 7-ld-e, 2a-b, 10, 13,14). However, in other corallites as septal lamellation
proceeds axial tabellae become also considerably
differentiated to achieve echigophylloid (or"clisaxophylloid") axial column (Figures 7-3d-f,
4, 5, 7, 11, 12, 15a). This tendency towards
differentiation of septal lamellae and axial
tabellae leads in the extreme case to reticulovesicular pattern in which axial tabellae aredominant and septal lamellae are weakly developed (Figure 7 -9b). Outline of axial column isround, sub elliptical or fusiform.
In longitudinal section, triareal arrangementof skeletal elements is very clear. Wall is moderately thick and feebly undulated. Dissepimentarium is occupied by 4 to 8 rows of small globose

842. Early Carboniferous corals from Omi Limestone

235

mm
15

Q)

:;

.

.

co

0 10

·•

CJ

-.
0

•

• ·••

I

....Q)
Q)

E
co
=0

••
•

••

I
I
I

5

..

•

I
10

15

numberFigure 6.

•

25

20

of

major

30

septa

Relationship between number of major septa and diameter of corallite in Akiyosiphyllum

sty[ophOlum Yabe and Sugiyama.

and large flattened dissepiments, which aresteeply inclined in the periphery and almost
vertical near the tabularium. Elongate dissepiments are present. Intrathecal dilation may occur
on the internal surface of the dissepimentarium,
forming an inner wall. Tabularium is wide,clearly differentiated from the dissepimentarium,composed of vesicular, arched and upwardly
convex tabulae which are gently or steeply ascending towards the axial column. They aremostly incomplete, but may be locally complete.
A few horizontal accessory plates occur in the
peripheral part. Axial column is also well differentiated from the tabularium, wide and stout
with no, a few or numerous axial tabellae steeply
inclined against the median plate. Calice is deep,
with prominent calicular boss.
Remarks:- The present form shows great variability in its skeletal construction in the mature
stages, and it may be morphologically divided
into at least three types as the following:
Type I-With no stereozone, concentric toanglo-concentric dissepiments, bluntly terminated or slightly clavate axial ends of major septa
which are mostly in contact with columella,fairly long minor septa and amygdalophylloid
axial column (e.g. OM 10004,10005).
Type 2-With imperfect stereozone, concentric
to anglo-concentric and herringbonal dissepiments, rapidly tapering axial ends of major septa
which are almost isolated from axial column,
short minor septa and echigophylloid (or "clisaxophylloid") axial column in which axial
tabellae become distinct (e.g. OM 10006-10008,
10010,10011).
Type 3 -With the skeletal elements similar totype 2, except for having reticulo-vesicularpattern of echigophylloid (or "clisaxophylloid")
axial column (e.g. OM 10012).
Thus these types may be apt to be treated as
representing three different species. However,as shown in Figures 7-1 0-ISb, there are further
gradational forms between these types, especiallybetween type 1 and type 2. Moreover, these236

Yasushi YOSHIDA, YujiOKIMURA andMakotoKATO

842. Early Carboniferous corals from Omi Limestonemorphological variations occur together at thesame locality and even in a single specimen.
Therefore they are best considered as intraspecific variations.
As a whole the present form is almost identical with the variable species, Akiyosiphyllum
stylophornm Yabe and Sugiyama (1942).
The present form also has some similarity
with Lithostrotion stanvellense described by
Benson and Smith (1923, p. 168, pI. 9, figs. 3,6), which is not identical with L.? stanvellensis(sic) proposed by Etheridge (1900, p. 20, pI. 1,
fig. 5; pI. 2, figs. 7,8) but may be congenericwith Akiyosiphyllum as Minato (1955, p. 168)
pointed out. However the latter has smaller axial
column compared to the present form, and isprovided with sharply bent tabulae in the periphery of the tabularium in longitudinal section.
Family Carcinophyllidae Fomitchev, 1953
Genus Carcinophyllum Thomson andNicholson, 1876

Type species (by subsequent designation ofThomson, 1880):-Carcinophyllum Kirsopiana(sic) Thomson, 1880
Remarks:- The possible synonymity between
Carcinophyllum and Axophyllum Milne-Edwards
and Haime (1850), has been accepted by many
authors (Hill, 1940, 1956, 1981; Wang, 1950;
Perret and Semen off-Tian -Chansky , 1971 ; Semenoff-Tian-Chansky, 1974; Poty, 1981, 1982).
However, the definite conclusion of the problem
should be reserved, because the lectotype of thetype species ofAxophyllum, A. expansum MilneEdwards and Haime (1950), has not yet been
fully redescribed by any authors. In the present
state of our knowledge, the authors would liketo consider Carcinophyllum as an independent

237

genus.

Carcinophyllum hasegawai, sp. nov.
Figures 9-1a-S, 10-1a-3c

Derivation of the specific name:-After Prof.
Yoshiyuki Hasegawa, who greatly advanced ourknowledge on the foraminiferal biostratigraphyof the Omi Limestone.
Material:- Thirty solitary corallites, fromwhich 78 transverse and longitudinal sections
have been prepared. Holotype IGSH-YY 10007,
Paratypes IGSH-YY 10008-10016.
Specific diagnosis :-Medium sized Carcinophyllum haVing well developed dissepiments,
narrow tabularium with steeply inclined dinotabulae, rhopaloid axial ends of major septa, longminor septa and thick septal lamellae which are
curving or sometimes irregularly twisted in themost advanced stage.
Description :-Corallum is solitary, trochoid toconico-cylindrical, and medium in size. Sometimes, two corallites belonging to different individuals are observed to grow parallel to andappressed with each other, so as to give a false
impression of a compound corallum (Figures 103a-c). Surface characters are unknown.
In transverse section, corallite is round inoutline, and 25 mm in diameter in the largest
corallite. Internally it consists of wall, dissepimentarium, tabularium and axial structure. Wallis moderately thick, comparatively smooth ormarked only by faint septal grooves and interseptal ridges in outer configuration. But it iscrenulated inside, corresponding to the positionof septa, except in early growth stages in which
lateral fusion of peripherally dilated septa produces a pronounced stereozone. Dissepimentarium is wide, varies in its diameter from 1/3 to+- Figure 7. 1-15. Akiyosiphyllum stylophorum Yabe and Sugiyama, all x3 except 6, which is x10. la-e.
Serial transverse (la-b, 1d-e) and longitudinal (1 c) sections (OM 10004), 2a-b. Transverse sections (OM 10005),
3a-f. Serial transverse sections (OM 10006), 4. Transverse section (OM 10007), 5. Transverse section (OM
10008),6. Transverse section (OM 10009),7. Transverse section (OM 10010), 8a-b. Transverse (8a) and longitudinal (8b) sections (OM 10011), 9a-b. Longitudinal (9a) and transverse (9b) sections (OM 10012), 10 Transverse section (OM 10013), 11. Transverse section (OM 10014),12. Transverse section (OM 10015), 13. Transverse
section (OM 10016),14. Transverse section (OM 10017), lSa-b. Transverse (1Sa) and longitudinal (IS b) sections(OM 10018).

Yasushi YOSHIDA, YujiOKIMURA andMakotoKATO

238

near to the axial structure but never connectedwith it except in very early growth stage, inwhich only the cardinal septum is firmly united
with the median plate in the axial structure(Figure lO-la). The axial ends of major septa
are clavate and rhopaloid. Minor septa alternatingwith the major are also fairly long, intruded into
the tabularium, with bluntly terminated axialends. Septa are in general radially arranged, butshow a somewhat pinnate arrangement in somecorallites. Septal fine structure is stout trabecular. As many as 41 major occur in the 25 mm
diameter corallite. Relationship between thenumber of major septa and the diameter ofcorallite is shown in Figure 8. Axial structure isround to sub elliptical in outline, occupies 1/5 to
2/5 of the diameter of corallite.1t is constructedby a thick, slightly undulating median plate withthick, irregular, curved and anastomosing septal

2/3 of the radius of corallite. It is composed oflarge and irregular lonsdaleoid dissepiments andnarrow, small concentric ones. Lonsdaleoid
dissepiments are already developed even in relatively early growth stages, though partially or
rudimentarily (Figure 9-2a), and soon come tooccupy a peripheral zone external to the septal
cycle in the midst of the young growth stages.
Intrathecal dilation is often very distinct andinner wall is clear in that instance. Tabularium
is narrow, where cut edges of tabulae are seen
between septa. Septa are moderately thick andin two orders, major and minor respectively.
Fossula is indistinct. Septa are interrupted fromthe wall by the development of lonsdaleoid
dissepiments, which leave only spiny projections
on vesicles. They are commonly straight in thetabularium, however slightly sinuous in thedissepimentarium. Major septa are long, extend

mm

~f

• •

-

20

Q)

•

•
•
•

-

...

«I

0
0

-...
-

•
•
••

Q)

Q)

E

••
•

15

0

10

«I

"0

•
5

•

• I
•

•• ••

I

•

•

•
•

•

•

•

•

•
15

20

25

!

!

!

30

35

40

number of major septa
Figu.re 8. Relationship between number of major septa and diameter of corallite in Carcinophyllum
hasegawal, sp. nov.

842. Early Carboniferous corals from Omi Limestonelamellae-approximately equal in number and thethickness to the major septa-, and thin, straightor inwardly convex axial tabellae which aresparsely disposed. Median plate is relatively longin early growth stages, becoming shortened in
the mature. Sometimes, in the most advanced
stage of larger corallites it becomes indistinguishable from septal lamellae, the feature presenting
somewhat an appearance of gangamophylloid
axial structure, in which septal lamellae are irregularly twisted (Figures 9-1e-f). Other different type of axial structure is observable in
one corallite, in which slightly flexuous septal
lamellae are radially arranged in a regular manneraround a short median plate (Figure 9-3b).
Simple budding is discernible in the holotype(Figures 9-1e-f) and in one of the paratype
specimens (IGSH-YY 10016): one or two small
offsets arise in the lonsdaleoid dissepimentariumof the mother corallite, and these offsets correspond in morphology to comparable ontogenic
stages of a mature corallite. In transverse sectionsof some corallites laterally projecting parts ofthe corallite probably indicate the presence oftalon (Figure 9-4).
In longitudinal section, trizonal arrangementof skeletal elements is very clear. The wall ismoderately thick and weakly undulated. Dissepimentarium is wide, with inner series of small andvertical dissepiments and outer series of large,
flattened and steeply inclined ones. Large elongate dissepiments are developed. Intrathecal
dilation may occur on the internal surface ofthe dissepimentarium. Tabularium is narrow,well differentiated from the dissepimentarium,and occupied by deeply dipping clinotabulae andhorizontal or sagging transverse tabulae. In one
corallite transverse tabulae are gently inclined
inward (Figure 1O-2b). All the tabulae are fairly
distantly spaced. Axial structure is also differentiated from the tabularium, consists of a thick,sinuous median plate, cut edges of thick, flexuous septal lamellae and thin, steeply ascending
axial tabellae which are straight or inwardly
convex. Calice is spreading and moderately deep,
with prominent calicular boss.
Remarks:-The present form falls in the group239

of Carcinophyllum with well developed lonsdaleoid dissepiments and a typical carcinophylloid
axial structure, but is different from the hitherto
described species of the genus in having longminor septa.
On the other hand, the present form has somesimilarity with Hiroshimaphyllum toriyamai(Minato, 1955), but the latter is a fasciculate anddendritic form, and has smaller corallites having
less numerous septa and more dense skeletal elements compared to the present form.
Family Pseudopavonidae Yabe, Sugiyama
and Eguchi, 1943
Subfamily Pseudopavoninae Yabe, Sugiyama
and Eguchi, 1943
Genus Hiroshimaphyllum Katoand Minato, 1974
Type species (by original designation):Lonsdaleoides toriyamai Minato, 1955
Hiroshimaphyllum simplex, sp. nov.
Figures lO-4a-7

Derivation of the specific name:-After thefeature of corallum having simply constructed
axial structure. Latin simplex-simple.
Material:-Four fasciculate colonies and single
fragmental corallite, from which eleven sections
are available for study. Holotype IGSH-YY
10017, Paratypes IGSH-YY 10018-10020.
Specific diagnosis :-Small sized Hiroshimaphyllum with less dilated internal skelton. Axial
structure is relatively simple in construction.
Description :-Corallum is compound, fasciculate and dendritic. Corallites are trochoid andsubparallel, closely situated and are often incontact with each other. Surface characters are
unknown.
In transverse section, corallite has round andcomparatively smooth outer configuration, andinternally consists of wall, dissepimentarium,
tabularium and axial structure. Corallite diameterreaches up to 10.0 mm in the largest corallite,
but commonly it measures 4 to 7 mm in themature stages. Wall is moderately thick and cre-

240

Yasushi YOSHIDA, Yuji OKIMURA and Makata KATO

Figure 9. 1- 5. Carcinophyllum hasegawai, sp. nov., 1, 3, 5 are x2.5 ; 2, 4 are x3. 1a-f. Serial transverse(la-b, 1d- f) and longitudinal (lc) sections (Holotype : IGSH-YY 10007), 2a-c. Serial transverse sections(Paratype : IGSH-YY 10008) , 3a- b. Longitudinal (3a) and transverse (3b) sections (Paratype : IGSH-YY 10009),
4. Transverse section (Paratype: IGSH-YY 100lD), 5. Transverse section (Paratype: IGSH-YY 10011).

842. Early Carboniferous corals from Omi Limestone

241

1a

1b

1c

3a

3b

6a
Figure 10. 1- 3. Carcinophyllum hasegawai, sp. nov., 1,3 are x3; 2 is x2.S. la- c. Serial transverse sections(Paratype : IGSH-YY 10012), 2a- b. Transverse (2a) and longitudinal (2b) sections (Paratype: IGSH-YY 100l3).
3a - c. Transverse (3a, 3c) and longitudinal (3b) sections (Paratype: IGSH-YY 10014).4 - 7. Hiroshimaphyllum
simplex, sp. nov., all x4.S. 4a - e. Serial transverse (4a, 4c- e) and longitudinal (4b) sec tions (Holotype: IGSH-YY
10017),5. Transverse section (Paratype: IGSH-YY 10018), 6a- c. Serial transverse sections (Paratype : IGSH-YY
10019),7 . Transverse section (Paratype: IGSH-YY 10020).

242

Yasushi YOSHIDA, YujiOKIMURA andMakotoKATO

nulated inside, corresponding to the position of
septa. Dissepimentarium is wide, varies in its
width from 1/4 to 1/2 of the radius of corallite.
It is composed of one to several rows of lonsdaleoid dissepiments of various size and one tothree rows of narrow, small, concentric ones.
Lonsdaleoid dissepiments are sometimes so
reduced as to be replaced by a thick stereowall
which is formed by lateral fusion of peripherally
dilated septa. Slight intrathecal dilation on theinternal surface of the dissepimentarium marks adistinct inner wall. Tabularium is wide, where
straight cut edges of tabulae are seen between
septa. Septa are in two orders, major and minor
respectively. Fossula is indistinct. Septa aremoderately thick, somewhat sinuous and become
discontinuous in the lonsdaleoid dissepimentarium where they are represented by spiny projections on the dissepimental vesicles. Major
septa fall short to the axial structure except inearly growth stages, in which the prolongation of
axial end of the cardinal septum makes an axial
structure. In one corallite (IGSH-YY 10019),
however, the cardinal septum is firmly connectedwith the median plate in the axial structure
through the g.rowth. The axial ends of major
septa are bluntly terminated and occasionallyslightly clavate. Minor septa alternating withthe major are fairly long, intruded into thetabularium. They attain 1/2 to 2/3 the lengthof the major. Septa are in general radially arranged, but show a somewhat pinnate arrangement in some corallites. Fine structure of septa
is trabecular. The number of major septa is
counted as many as 21 in a corallite of 8.7 mm
in diameter. Relationship between the numberof major septa and the diameter of corallite isshown in Figure 11. Axial structure is a mereelongation of the cardinal septum in early
growth stages as above described. In the mature
stages axial structure is round to sub round inoutline, occupies 1/5 to 1/3 of the diameter ofcorallite. It is simply made up of a thick andsomewhat undulating median plate, several,
irregular and curving septal lamellae and one totwo rows of thin, straight or inwardly convex
axial tabellae. In two corallites (IGSH-YY 10019,

-...
..
o

5

Q)
Q)

E
.!!!
"C

5

10

15

20

number of major septa

Figure 11. Relationship between number of major
septa and diameter of corallite in Hiroshimaphyllum
simplex, sp. nov.

10020) no axial tabellae are developed. Twomodes of increase are observable, namely peripheral and lateral. In the peripheral increase, one
small offset arises in the dissepimentarium of
the mother corallite (Figure 1O-4a), while in thelateral increase, it is sprung out from the sidewall of the mother corallite in a form of raindrop(Figure 10-7).
In longitudinal section, trizonal arrangementof skeletal elements of a corallite is clearly recognizable. Wall is moderately thick and wavy.
Dissepimentarium is absent in early growth stage,
but well developed in the mature stages, withlarge, flattened and steeply inclined dissepimentsin the periphery and small, vertical ones near thetabularium. Intrathecal dilation occurs on theinternal surface of the dissepimentarium. Tabularium is wide, well differentiated from the dissepimentarium in the mature stage. It consists ofmostly complete transverse tabulae which are
horizontal or slightly sagging and sometimes
gently ascending towards axis. They may belocally incomplete. Clinotabulae may be present
in the mature stage. In vertical distance of 2 mm,
3 to 5 tabulae are counted. Axial structure isalso well differentiated from the tabularium,composed of a thick, sinuous median plate, cut
edges of thick septal lamellae and thin, steeply
ascending axial tabellae which are sparsely disposed.
Remarks:-Five species have been ascribed to
the genus Hiroshimaphyllum, namely H. enorme(Ozawa, 1925), H. toriyamai (Minato, 1955), H.

842. Early Carboniferous corals from Omi Limestone
shikokuense (yamagiwa, 1961), H. compactum
Wu and Zhang (1979) and H. crassithecum Wu
and Zhang (1979). However, the present form
is different from the above listed species inhaving smaller corallites, less dense skeletal
elements and less complicated axial structure.
On the other hand, the present form has somesimilarity with Carcinophyllum hasegawai, sp.
nov. described in this paper, but the latter is asolitary form, and has larger corallite comparedto the present form.

Acknowledgments
The authors would like to express their appreciation to Professor Emeritus Akira Hase ofHiroshima University for his leading and encouragement. Acknowledgement is also due toProfessor Yoshiyuki Hasegawa and Dr. Isao
Niikawa of Niigata University for their instructive advices and suggestions in various ways. The
authors are much indebted to the Myojo Cement
Co., Ltd. for every facility in the field. Thanks
are extended to Messrs. Hideo Takahashi and
Akito Magai of Hiroshima University for preparing thin sections. This study was partly
financed by the Grant in Aid for Scientific Researches from the Ministry of Education.

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244

Yasushi YOSHIDA, Yuji OKIMURA andMakoto KATO

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25-40, pIs. 1-3 (in Chinese with English abstract).
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842. Early Carboniferous corals from Omi LimestoneVii, C.C., Lin, I. T., Huang, C. H. and Tsai, T. S. (1978):
Early Carboniferous stratigraphy and corals ofeastern Xingjiang. Prof Pap. Strat. Paiaeont., no. 5,

Akiyoshi tktr, Fukugakuchi

245

p. 1-77, pis. 1-16 (in Chinese with English abstract).

m*". 0, Kurohime ~9I:i, Niigata $T~, Nishikubiki jffi~~, Omi

lIfw.
lIf#!F6JJ<::!E}Mi't(7)litr.ftil6hR*c-lf" /' ::1(r.6 : $T~JIll<lIfw6JJ<::!E}(7)mrf$l.p I?'.!!t~t.:-If" /' ::f(r.6~i!€t±l Lt.::o ::. (7) -If" /' ::t(r.6 (,f.~(7)f~f.Ili;~~lt, tkti"fjJJ<::!E}(7) N agatophyllum satoi *(7).:t.h C ~(J;(I'iJ~~.ht.:-If"/' ::f(r.6(7)? 'I? , ~i!€-t{:,t.:vt ..U.:<, 7.)-~,)tt Jt (7) ? ;t ""('il! ~ C ~ ;t I? .h {:, 2 fll!:to .t L1 3 $T fll! ~ ;~c !/lit -t {:, : Cyathaxonia cf r.

C. cornu

L, f&.ftile··tt-ill:H~jf- L -n,{:,oMichelin, Clisiophyllum kurohimense, sp. nov., Akiyosiphyllum stylophorum Yabe andSugiyama, Carcinophyllum hasegawai, sp. nov., Hiroshimaphyllum simplex, sp. nov.
!Iff.
;IJ~~ IDJ(

am

rtjl:tt.= .

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 246-255,4 Figs., December 30,1987

843. MIOCENE MOLLUSCS FROM THE KOZONO FORMATION,SAITAMA PREFECTURE, CENTRAL JAPAN*
RYUICHI MAJIMA
Institute of Geoscience, University of Tsukuba,
Ibaraki, 305

and
HIROKAZU TAKAHASHI
University of Tsukuba Junior High School at Komaba,
Setagaya, Tokyo, 154

Abstract. A mol1uscan assemblage composed of twelve species occurs in the Miocene
Kozono Formation, near Yorli, Oosato-gun, northern Saitama Prefecture. This assemblage isconsidered to have lived in a tidal sandflat near to an estuary and is comparable to the estuarine
tidal flat community, characterized by arcids and potamidids, of the early middle Miocene
Kadonosawa-type Fauna. The four species of Potarnididae, Tateiwaia tateiwai (Makiyama), T.
yamanarii (Makiyama), Vicaryella atukoae (Otuka) and V. ishiiana (Yokoyama) are described
for the first time from the Kozono Formation.

Introduction

the Arakawa River, about 80 m upstream of the
Tamayodo-Oohashi Bridge, about 1500 m ENE
of Yom, at lat. 36°7'6"N., long. 139°7'51 "E.,in Oosato-gun, northern Saitama Prefecture
central Japan (Figure 1).
'
The present assemblage occurs in a stratigraphic interval about 4 m thick, which is composed of dark yellowish brown, fine-grainedsandstone (A in Figure 2) of the Miocene Kozono
Formation. The sandstone grades laterally into
conglomerate and is overlain by poorly sorted
sandstone that contains abundant plant fragments (Figure 2).
The Kozono Formation is the stratigraphicallylowest among the Neogene formations exposed
along the Arakawa River, near Yorii and consistsof conglomerates, sandstones, mudstones andtuff. Along the Arakawa River, the Kozono Formation lies in fault contact with pre-Neogene
sedimentary rocks and crystalline schists, and isdivided into two outcrop areas, the Tachigase(west) and Kozono (east) areas, by NW-SE

Miocene estuarine tidal flat molluscs havebeen reported from Saitama Prefecture by
Watanabe et al. (I950) and Hatai and Masuda(I962), but those workers did not described orillustrated the fauna. During the spring of 1987,
the authors collected a small molluscan assemblage from the Miocene Kozono Formation thatis exposed in a cliff along the left bank of the
Arakawa River, near Yorii, Oosato-gun, Saitama
Prefecture, central Japan (Figure 1). This assemblage is comparable to the estuarine tidal flat
community of the early middle Miocene Kadonosawa-type Fauna (Otuka, 1939; Chinzei, 1978)
known from scattered localities elsewhere in
Japan.
Location and stratigraphic setting
Fossil locality is in a cliff on the left bank of*Received August 31, 1987

246

843. Miocene mol/uses from the Kozono Formation

247

Yorii
... A'N
2kll

A'

A

- 200

200 -

Om

1

-200

. Takasaki 0 ~~Shlmomda'o. ._..

... :'

O~se

- -

N

....

Koufu

"

.... ~:.~' ...•..•...

o

'.

.'.~
.~

,
,

...•. -.

~......
............

....

.....

0 Higashimatsuyama '<':".... ............ ... .
...... ~{\.

.. \.........

. ..

o.

~

.......

....

. Kumagaya .......( .....

........ ...... Chichibu,......

....'.

~_.. _LEGEND."D

QUATERNARY

B

TUFF

ID

ARAKAWA
FORMATION
KOlONOFORMATION~•

PRE-NEOGENE/'STRIKE AND DIP

.....

,

/
'~
....

,...,
:z:
,...,

FAULT
./

/

an

./

CONCEALED FAULT

Figure 1. Fossil locality and geology along the Arakawa River, Yorii-machi, northern Saitama Prefecture.
Geologic map modified from Majima (1978MS).

RyuichiMAJIMA and Hirokazu TAKAHASHI

248

lower part of the Kozono Formation is characterized by abundant conglomerates, sandstones
and rare tuff. The upper part of the Kozono
Formation is characterized by abundant mudstones with frequent intercalations of tuff. The
Kozono Formation is conformably overlain by
the Arakawa Formation that is composed ofalternating sandstone and mudstone (Figure 1).

Abundant plantfragments

Molluscs shown ( A)in Table 1

Modes of occurrence

EE~"p·-:It~;~~Cultellus sp.
Turritella sp.

2m

Fossils are aggregated in lenticular beds lessthan 5 cm thick, and may occur sporadically (Ain Figure 2). Modes of fossil occurrences inshell-aggregated lenticular beds are given in
Figures 4-9a-l Ob in stereopairs.
Fossils are preserved as casts or molds. Gastropods are usually well preserved, but most specimens of Vicaryella ishiiana are generally secondarily depressed (Figures 3-19-22) except
for juveniles (Figure 3-17) and one adult (Figure3-18). Bivalves are usually poorly preserved.
They are secondarily deformed and bear many
fractures (Figures 4-5,7,8).
Faunar{\Bg~12e.m

1~1~r~~~lJI3s

Figure 2. Columnar section of fossil locality(Figure 1). The estuarine intertidal molluscs occur infine-grained sandstone (A). 1: Molluscan fossils. 2: Finegrained sandstone. 3: Poorly sorted sandstone. 4: Conglomeratic sandstone. 5: Conglomerate. All the beds
are a lower part of the early middle Miocene Kozono
Formation.

faults (Figure 1). The Kozono Formation in the
Tachigase area, which yielded the present molluscan assemblage, is complexly folded andfaulted and the sequence of strata is unclear.
The Kozono Formation of the Tachigase islithologically comparable to that of the lower
part of the Kozono Formation in the Kozono
area where the formation dips northeast. The

Twelve species of molluscs, consisting of eightgastropods and four bivalves, have been identified. Their relative abundance in the sample issummarized in Table I. Tateiwaia yamanarii isthe most abundant species in the collection.
More than 50 specimens were obtained. The
other species occur at much lower densities.
With the exception of Tateiwaia tateiwai andVicaryella ishiiana, none are represented by morethan 10 specimens.
The abundant occurrence of potamidids(Cerithidea sp., Tateiwaia tateiwai, T. yamanarii,
Vicaryella atukoae and V. ishiiana) suggests thatthe assemblage may have lived in an intertidal
sand flat near to an estuary, and in a tropical tosubtropical habitat. The family Potamididae
typically occurs in great abundance in mangroveswamps of brackish-water bays and estuaries.
The present molluscan assemblage clearly
indicates an early middle Miocene age. The

843. Miocene molluscs from the Kozono Formation

249

Table 1. Faunal list and relative abundance of species in the collection from the Kozono Formation. A = morethan 25 specimens; C = 11-25 specimens; F =5-10 specimens; and R =fewer than 5 specimens.
Species

Relative abundance

Gastropoda
Margarites? sp.
Cerithidea sp.
Tateiwaia tateiwai (Makiyama)
Tateiwaia yamanarii (Makiyama)
Vicaryella atukoae (Otuka)
Vicaryella ishiiana (Yokoyama)
Pollia sp.
Hemijitsus? sp.
Bivalvia
Striarca sp.
Saxolucina cf. khataii (Otuka)
Clementia sp.
Dosinia sp.

age of the assemblage is evaluated in termsof the molluscan faunal characteristics of theJapanese Neogene (Chinzei, 1978; Tsuchi andShuto, 1984). The present assemblage is comparable with a tropical to subtropical estuarine
tidal flat community, which is characterized by
the co-occurrence of arcids (Striarca uetsukiensis
and Anadara (Hataiarca) spp.) and potamidids(Vicarya spp., Vicaryella spp., Tateiwaia spp.
and others) (the "Arcid-Potamidid fauna" of
Tsuda, 1965), of the early middle Miocene
Kadonosawa-type Faune (Otuka, 1934; Chinzei,1978).
Systematic paleontology
Phylum Mollusca
Class Gastropoda
Order Mesogastropoda
Family Potamididae
Genus Tateiwaia Makiyama, 1936
Type species. - By original designation,
Batillaria tateiwai Makiyama, 1926.
Tateiwaia tateiwai (Makiyama, 1926)
Figures 3-2-8Illustrations

F
R

C
A

R
C
F
R

F
F
R

R

Figure 3-1
Figure 3-2-8
Figure 3-10-16
Figure 3-9
Figure 3-17-22
Figure 4-1a-3
Figure 4-4
Figure 4-6
Figure 4-5
Figure 4-8
Figure 4-7

Batillaria tateiwai Makiyama, 1926, pp. 147-148, pI.
12, figs. 5,6;? Otuka, 1934, p. 624, pI. 49, fig. 71;
Nomura, 1935, p. 228, pI. 17, figs. 30-33.
Batillaria (Tateiwaia) tateiwai Makiyama, Makiyama,
1936, p. 219; Fujie and Uozumi, 1957, p. 502, pI.
24, fig. 6; Okamoto et al., 1978, pl. 1, fig. 10.
Tateiwaia tateiwai (Makiyama), Itoigawa, 1978, pI. 2,
fig. 5; Taguchi et al., 1979, pI. 3, figs. 24-26;
Takayasu, 1981, p. 92, pI. 1, figs. 6, 7; Taguchi,
1981, pI. 4, fig. 11; Takahashi, 1984, pI. 1, fig. 7;
Itoigawa and Shibata, 1986, pl. 16, fig. 3.
Cerithium sakamotoi Yokoyama, 1929, p. 367, pI. 70,
fig. 4.

Measurements.-Largest specimen, height 18.8mm (incomplete), diameter 7.1 mm (incomplete)[IGUT 11116-5: Figure 3-6] .
Discussion.-Eleven specimens were examined.
All lack proto conchs and apertural parts. The
whorls are weakly shouldered and their sides areflattened. The whorl sculpture shows a pronounced change during ontogeny. The preserved
early whorls have eleven well-defined axial ribs.
On the later whorls, the axial ribs become weakor disappear, and three weak but distinct spiralthreads appear. The upper thread bears elevenwell-defined spines per whorl, the middle thread
has twenty-two nodes, and the lower thread isnearly smooth.
The characters of the present specimens are

250

RyuichiMAJ/MA and Hirokazu TAKAHASHI

843. Miocene molluscs from the Kozono Formation
nearly identical with Makiyama's (1926) originaldescription of the species, except for finer
sculpture that is not preserved in the present
specimens and for the presence of sculpture on
the middle threads of the later whorls in present
specimens. The observed specimens bear twentytwo nodes per whorl on the middle thread of thelater whorls whereas Makiyama's specimens havea smooth middle thread. This difference in sculpture is an individual variation of the species.

Tateiwaia yamanarii (Makiyama, 1926)
Figures 3-10-16
Batillaria yamanarii Makiyama, 1926, pp. 148-149, pl.
12, fig. 4; Otuka, 1934, p. 624, pI. 49, figs. 80, 81;
Nomura, 1935, p. 228, pl. 17, figs. 27, 28;? Kanno
and Ogawa, 1964, pI. 2, fig. 17; Mizuno, 1964, pl. 1,
figs. 1-3.
Batil/aria (Tateiwaia) yamanarii Makiyama, Makiyama,
1936, pp. 219-220; Fujie and Uozumi, 1957, pp.
502-503, pl. 24, figs. 5, 7; Okamoto and Terachi,
1974, pI. 47, fig. 12; Sasaki and Ogasawara, 1986,
pI. 6, figs. 6a-b.
Tateiwaia yamanarii (Makiyama), Itoigawa et aZ., 1974,
pp. 134-135, pI. 40, figs. 23-24b; Itoigawa andNishikawa, 1976, pI. 35, fig. 15; Itoigawa, 1978, pI.
2, fig. 4; Taguchi et aZ., 1979, pI. 3, figs. 27,28;
Takayasu, 1981, pp. 92-93, pI. 1, figs. 8,9; Itoigawa
et aZ., 1981, pI. 30, figs. lOa-b; Taguchi, 1981, pl. 4,
fig. 12; Itoigawa et aZ., 1982, p. 173; Okamoto et aZ.,
1983, pI. 23, figs. 10-11; Okumura, 1983, pI. 50,
figs. 2a-b; Takahashi, 1984, pI. 1, figs. 9-11;
Nakagawa and Takeyama, 1985, pl. 15, figs. 7,8;
Ozawa et al., 1986, pI. 12, fig. 3; Itoigawa andShibata, 1986, pI. 16, fig. 4.
Cerithium proavitum Yokoyama, 1929, p. 336, pI. 70,
fig. 3.

Measurements. -Largest specimen, height 20.5mm (incomplete), diameter 12.4 mm (incomplete) [IGUT 11118-3: Figure 3-12].
Discussion. -More than fifty specimens were
examined. Protoconchs of all specimens are251

missing. Tateiwaia yamanarii is characterized bymedially angulate whorls; angularly depressed
sutural part; eight or nine axial ribs per whorl,
the axial ribs slightly prosoclinal, becomingcoarser spines where they override the angulation, and not aligned from whorl to whorl; spiralsculpture of twelve to thirteen threads, with thespiral threads coarsest and crossed by the spines
at the median whorl angle. The base is circumscribed by two spiral cords.
Like Vicarya spp. and Vicaryella spp., Tateiwaia
yamanarii is among the morphologically mostdistinct and most common species in the estuarine tidal flat community of the early middle
Miocene Kadonosawa-type Fauna. So, thisspecies is one of the best indicators for thefaunas of Kadonosawa age.
Genus Vicaryella Yabe and Hatai, 1938

Type species. - By original designation. Vicary ella tyosenica Yabe and Hatai, 1938.
Vicaryella atukoae (Otuka, 1934)
Figure 3-9
Batillaria atukoae Otuka, 1934, pp. 623-624, pI. 49,
figs. 69, 70;? Nomura, 1935,p. 228, pI. 17, fig. 23;? Fujie and Uozumi, 1957, p. 503, pI. 24, fIg. 8.
Cerithium (Proclava) ancisum (Yokoyama), Otuka,
1938, p. 42, pI. 4, fig. 36 [not Potamides ancisum
Yokoyama, 1929].

Measurements. -Height, 21.4 mm (incomplete),diameter, 9.8 mm (incomplete).
Discussion.-Only one specimen was examined. Eight whorls are preserved but the protoconch and apertural parts are missing. The
whorls are sculptured with three well-definedspiral cords bearing granular tubercles. In theearly whorls, tubercles on the three cords areapproximately equal in strength and eighteen in+- Figure 3. Fossil potamidids collected from the Kozono Formation. All figures are x2, unless otherwise
stated. All specimens are rubber casts made from the external molds.
1. Cerithidea sp. IGUT 11115. 2-8. Tateiwaia tateiwai (Malciyama). 2, IGUT 11116-1; 3, IGUT 11116-2; 4, IGUT
11116-3; 5, IGUT 11116-4; 6, IGUT 11116-5; 7, IGUT 11116-6; 8, deformed, IGUT 11116-7.9. Vicaryellaatukoae (Otuka). IGUT 11117. 10-16. Tateiwaia yamanarii (Makiyama). 10, IGUT 11118-1; 11, IGUT 11118-2;
12, IGUT 11118-3; 13, IGUT 11118-4; 14, IGUT 11118-5; 15, IGUT 11118-6; 16, IGUT 11118-7. 17-22.
Vicaryella ishiiana (Yokoyama). 17, juvenile, IGUT 11119-1, x2.8; 18, IGUT 11119-2; 19, deformed, IGUT
11119-3; 20, deformed, IGUT 11119-4; 21, deformed, IGUT 11119-5; 22, deformed, IGUT 11119-6.

252

Ryuichi MAJIMA and Hirokazu TAKAHASHI

Figure 4. Fossil gastropods and bivalves collected from the Kozono Formation. All figures are x2, unlessotherwise stated. All specimens are rubber casts made from the external molds. 1a-3 . Pollia sp. 1a-b, IGUT
11120-1; 2, IGUT 11120-2; 3, IGUT 11120·3 . 4. Hemifusus? sp. Later whorls missing, IGUT 11121. 5. Saxolucina cf. khataii (Otuka) . IGUT 16127. 6. Striarca sp. Interior view , IGUT 11123. 7. Dosinia sp. Dorsal view,
showing a distinct lunule, IGUT 11124 , xL? 8. Clementia sp. IGUT 11125. 9a - b. Stereopair, showing mode offossil occurrence. IGUT 11126, xO .7. The block contains Cerithidea sp., Tateiwaia tateiwai (Makiyama), T.
yamanarii (Makiyama), VicaryeUa ishiiana (Yokoyama) and bivalve fragments. lOa-b. Stereopair, showing modeof occurrence of Tateiwaia yamanarii (Makiyama). IGUT 11127 , xO.7.

843. Miocene molluscs from the Kozono Formation
number on each cord of a whorl. The granular
tubercles of the upper cord develop gradually
into spinose tubercles during growth, and become fewer in number than tubercles on otherspiral cords on the same whorl. On the lastwhorl, the spinose tubercles of the upper cord
are nine in number, whereas tubercles of theother two cords are twenty-seven in number.
The base is circumscribed by two spiral cords,
the upper of which is weakly granulated. The
columella is weakly but distinctly folded.
Vicaryella atukoae is similar to Potamides
ancisus Yokoyama, 1929 in whorl sculpture, but
the whorl sculpture of the former is coarser thanthat of the latter, and the former's columella isdistinctly folded. Potamides ancisus Yokoyama
has no columnar fold (Masuda, 1967).

Vicaryella ishiiana (yokoyama, 1926)
Figures 3-17-22
Cerithium baculum Yokoyama, Yokoyama, 1925, p. 12,
pI. 2, fig. 6 [not Cerithium baculum Yokoyama,
1924].
Vicaryella bacula (Yokoyama) [not Cerithium baculum
Yokoyama, 1924], Okamoto and Terachi, 1974, pI.
47,fig.10j Taguchietal., 1979, pI. 3, figs. 29, 30.
Cerithium ishiianum Yokoyama, 1926, p. 218, pI. 28,
figs. 11, 12.
"Vicaryella" ishiiana (yokoyama), Yabe and Hatai,
1938,p.169.
Vicaryella ishiiana (Yokoyama), Oyama and Saka, 1944,
pp. 139-140, pI. 14, figs. 5-8b; Kamada, 1960, p.
284, pl. 31, figs. 4a-b, 8, 9; Kamada, 1962, p. 152,
pI. 18, figs. 15, 16; Masuda, 1967, pp. 1-2, pI. 1,
figs. 1a-2b; Ogasawara, 1973, pI. 13, fig. 22; Itoigawa et al., 1974, p. 137, pI. 42, figs. 5a-b; Kim etal., 1974, pp. 279-280, pI. 39, fig. 2; Yoon, 1976,
p. 64, pI. 1, figs. 5, 6; Yoon, 1979, p. 22, pI. 5, fig.
10; Itoigawa et al., 1981, pI. 30, figs. lla-b, 12a-b;
Itoigawa et al., 1982, pp. 171-172; Okamoto et al.,1983, pI. 23, figs. 1-3; Nakagawa and Takeyama,
1985, pI. 15, fig. 9; Okamoto et al., 1986, pI. 19,
figs. 1,2; Itoigawa and Shibata, 1986, pI. 16, fig. 9.

253

and much narrower than their interspaces. They
are all beaded except a suprasutural one thathas a flat-topped surface. A sub sutural beadedrow develops into spinose tubercles, numbering
14 or 15 on average, although one specimen(IGUT 11119-2: Figure 3-18) has 18. Secondaryinterstitial spirals appear in the middle of theshell, and tertiary ones occur rarely on the later
whorls. Base weakly concave, set off from thewhorl sides by an acute angle, ornamented withseveral fine and smooth spiral threads, and circumscribed by two flat-topped, smooth spirals.
Outer lip is broken. Inner lip is smooth, covered
with a thick callous forming a semicircular plate.
Siphonal canal is short.
This species is characterized by its highly
turreted shell with many spiral cords that have asmooth or somewhat granular surface, of which
the subsutural cord is the strongest and has about
14-15 spinose tubercles.
Vicaryella notoensis Masuda (1956, pp. 161162, pI. 26, figs. 2-4) is quite similar to thepresent species, but differs by having 24-25
spinose tubercles on the sub sutural spiral cordand secondary spirals that often become asstrong as primary ones.
Vicaryella atukoae (Otuka) differs from thepresent species by having three granular spiralcords per whorl, and about ten strong spinose
tubercles on the sub sutural spiral cord of thelast whorl.
Acknowledgments
We extend our sincere appreciation to Prof.
Hiroshi Noda of the Institute of Geoscience, University ofTsukuba, and to Dr. Louie Marincovich,Jr. of the U.S. Geological Survey for their carefulreading of the manuscript.

Measurements. -Largest specimen, height 33.5

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254

Ryuichi MAJIMA and Hirokazu TAKAHASHI

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Arakawa 5i'LJII. Kozono 'H';'1. Tachigase lL'ri'.liSi. Yorii '!.flill.

*,"pif\; r=l
J;,'lj ];JIj!;(.1)'H~'I~i£cp1'frUtJt ftD : J;,'ljH;tktjJr.~~JrjH'j-ili(.1) jj'L)llimllJ!(~':'JE~-r-.o Ifl1'fr~HI!1\I~iJ' G12f.1l J: I) f.c.o !W\{it;:lIVJ4o/.iltf~b;i&W-r-.o, .:. (.1)ilf~fH;ti"J Q H.ili:(.1)~o:vJr9(MtO.:.1:.\i:!, L-C~ 'f.: C ~;t Gh. q,WJq,~tltlltrWJ(.1)t'~ / iJ'-(~~ill!J4o/.i1l¥p.J(.1) 7;f 7/1 m~? ~ .=. j-~(.1)J1Hl::H':' J: -?-C
!j>H~ -':Ht G h .0 l+Jl ~h: i"J Q 1l¥ ~ ~.:. .It ~ ~ h .0, ? ~ .=. j- fJ~ (.1) 4 l:!lL Tateiwaia tateiwair..,(Makiyama), T. yamanarii (Makiyama), Vicaryella atukoae (Otuka) :j:o J: (J V. ishiiana(Yokoyama) Ii, 'H~I~i.I'GfJJ/5I)-C~cJllt~h.o,r,,'~Illfr- . il'Ii~'t-;;'¥O

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148 , pp. 256 - 275 , 5 Figs. , December 30 , 1987

844. TRIASSIC AND JURASSIC RADIOLARIA FROM
THE NADANHADA RANGE, NORTHEAST CHINA *SATORU KOJIMA and SHINJIRO MIZUTANIDepartment of Earth Sciences, Nagoya University, Nagoya 464

Abstract. Triassic Radiolaria from bedded chert and Jurassic Radiolaria from siliceous
shale in the Nadanhada Range, Northeast China are described; they are Capnodoce traversi.
Eucyrtidiellum ptyctum. E. unumaense, Guexe/la nudata. Livarella validus, Parahsuum(?) sp.
A, Pentactinocarpus sp. A, Poulpus curvispinus. Pseudostylosphaera japonica. P. cf. hellenica. P.
cf. tenue, P. sp. A, P. sp. B, P. sp. C, P. sp. D, P. sp. E, Stichocapsa convexa, Triassocampe
deweveri, T. sp , A, Tricolocapsa(?) [uslformis, T. plicamm, T. tetragona, T. cf. mesti, Yeharaia
annulata, Y. japonica and Y. sp. A. Other genera (species undetermined) are also illustrated.
Ages of the bedded chert and siliceous shale are assigned to middle to late Triassic (late Anisianto Ladinian ; late Carnian to Norian) , and to middle Jurassic (Bathonian to Callovian), respectively.

terrane , chaotic and incoherent sedimentarycomplexes called olistostrome or melange are
distributed ; they comprise blocks of various sizes(from a few centimeters to several kilometersin thickness) , a wide ranging ages (Carboniferous
to late Jurassic) and varying rock-types (limestone , greenstone, bedded chert , shale , etc .) which
are enclosed in the JUrassic to earliest Cretaceous
clastic matrix . A lithologiC association of thesame kind of rocks , radiolarian assemblages andgeologiC structure are traceable to the Tamba
area in the west and to the Ashio area in the east;
thus, the geologic body of these areas is collectively called the Tamba-Mino-Ashio terrane .
The northern part of the mainland of China
is underlain by the Sino-Korean paraplatform ,the Inner Mongolian-Great Khingan fold system,
the Jilin-Heilong Jiang fold system and so forth(Ren et al., 1980), where few bedded chert formations have been reported to occur. Even whendescriptions of chert are presented, most ofthem are concerned with chert concretions contained in limestone beds and are of secondary
origin. Fossil-bearing cherts or siliceous rocks,
particularly of Mesozoic age , are extremely rare
and almost absent except for the northeastern

Introduction
Recent progress in Mesozoic radiolarianbiostratigraphy has made a profound contribution to the geology of Mesozoic and Paleozoic
sedimentary complexes distributed in western
North America , Japan and Europe , and the results have a great influence on the tectonic in ter·pretations of these regions . For example , theMino terrane in central Japan is composed ofgreenstone , limestone , bedded chert , sandstoneand shale , and these rocks were long believed tobe late Paleozoic in age based on fusulinaceans
and corals in limestone. Recently , however,
Triassic and JUrassic Radiolaria have been obtained from chert and shale . This fact indicatesthat the rocks in the Mino terrane are not Paleozoic , but mostly Mesozoic in age (e.g. , Mizutani
et al. , 1981 ; KOjima, 1982 , 1984). The radiolarian biostratigraphy also revealed that thegeologic structure of Mesozoic and Paleozoic
sedimentary complexes of the Mino terrane wasexceedingly complicated. In many areas of the*Received June 23 , 1987; revi sed manuscript acce pted
Octob er 23 , 1987.

256

844. Triassic and Jurassic Radiolaria from China
extremity, the Nadanhada area. Mesozoic formations of north and northeast China are mostly
characterized by terrestrial deposits and subaerial
volcanic rocks.
As early as the 1950's, the Radiolaria-bearing
cherts are known to be distributed in the Nadanhada Range (Yabe, 1959; Yabe and Ohki, 1957).
They noted that sandstone, chert, slate, conglomerate and a lesser amount of limestone occurred in the area. Most of these rocks were considered to be Jurassic in age. (e.g., Chinese
Academy of Geological Science, 1976), although
no reliable index fossils had been found. Li et al.
(1979) reported the occurrence of Carboniferous
and Permian fossils together with Radiolaria
from the Nadanhada Range. Furthermore, Fengand Yang (1984) pointed out the distribution of
sedimentary complex having a chaotic nature in
the northeastern margin of the Chinese mainland.
Recently, Wang et al. (1986) have disclosed theoccurrence of late Triassic formation in the
Nadanhada area, and discussed the possibility ofwidespread distribution of the Triassic rocks.
From these lines of evidence, it is presumed that
the Nadanhada Range was a northern extensionof the Tamba-Mino-Ashio terrane, prior to the
opening of the Sea of Japan, and that a superterrane, consisting of the Nadanhada terrane,part of Sikhote Alin, and Tamba-Mino-Ashio
terrane, represents an ancient accretion complex
formed during a time period from the Jurassic
to the beginning of Cretaceous,at the continental
margin of East Asia (Mizutani, 1986, 1987).
Terrane analysis has made a fruitful advancesince 1975 in the circum-Pacific region, especiallyin western North America (e.g., Coney et al.,
1980; Monger and Irving, 1980; Howell et al.,1985). A tectonostratigraphic terrane is definedas "a fault-bounded package of rocks of regional
extent characterized by a geologic history which
differs from that of neighboring terranes"(Howell et al., 1985). Intraterrane stratigraphy
and structure have been examined by utilizing
microfossils, such as Radiolaria and foraminifers
in addition to the ordinary field investigations.
Interterrane relationship, on the other hand, isinferred from paleomagnetism, paleogeography257

and paleobiogeography. Wrangellia is one of thebest examples investigated by these methods inthe early stage of the development of terraneconcept (Jones et al., 1977). The Tamba-MinoAshio terrane and its probable extension, theNadanhada Range, play an important role as a
key terrane to reconstruct the East Asian collage,as Wrangellia does.
Following our preliminary report (Mizutani
et al., 1986), this paper describes in detail theoccurrence of the characteristic species of Radiolaria collected from the Nadanhada Range anddiscusses ages of Radiolaria-bearing rocks andJurassic radiolarian paleobiogeography.
Geologic setting
The Nadanhada Range in Northeast China
forms part of the Nadanhada eugeosyncline foldbelt of Ren et al. (1980) or of the Nadanhada
ophiolite belt of Li et al. (1982) and Zhang et al.

JMPl299
JMPl368
JMPl369
JMPl371**JMPI429
JMPl320Shichang
JMPl331
Erlianqiao
JMPl332

CHI N A
Shendingshan
A

10
!

20km
,

Figure 1. Index map of the Nadanhada Range,
Northeast China. Numbers (JMP1331 etc.) are localities
of samples treated in this paper.

258

Satom KOJIMA and Shinjiro MIZUTANI(1984). To the south of the Nadanhada area
there distributed is the late Proterozoic Khanka
massif, and to the east and north of the area
there is the Sikhote Alin fold belt. To the west
there occurs the Jiamusi microcontinent composed of the Precambrian basement covered with
an Upper Proterozoic formation with the Ediacara fauna (Zhang et al., 1984). Serpentinite
and glaucophane-schist found between the
Nadanhada Range and the Jiamusi microcontinent (Zhang et al., 1984) might be indicative ofa suture zone between them.
The Nadanhada area is underlain by the
Paleozoic and Mesozoic sedimentary complexes
made up of greenstone, limestone, bedded chert,
sandstone and shale, which crop out sporadicallyin quarries and roadside cuttings. Lenticularbodies of limestone, about 10 meters thick,are seen at Erlianqiao (Figure 1), embedded
as olistolith together with blocks of basic lava
in weakly sheared sandstone and shale. The
limestone is massive, homogeneous and grayin color. Middle Carboniferous fusulinaceans(Profusulinella sp., Fusulinella eopulchra Rauser,
F. subpulchra submesopachis Putrja) and corals(Donophyllum sp., Koninckocarinia sp.) are reported from this limestone by Li et al. (1979).
They also described the occurrence of Carboniferous fusulinaceans (Eostaffella, Fusulinella,etc.) and Permian fusulinaceans (Schwagerina,

Chalaroschwagerina, Paraschwagerina, Pseudoschwagerina, Neoschwagerina, Pseudodoliolina, Kahlerina, Verbeekina, Reichelina, Rauserella, etc.)
fusulinaceans from other limestone bodies andradiolarian fossils (Dictyomitra, Theocampe,
Cenosphaera, Hemicryptocapsa, etc.) from red
shales in the Nadanhada Range. Later, Han(1982, 1985) described the fusulinaceans in detail. Pillow basalts, amygdaloidal and considerably altered, are well exposed at a road cut about
10 km east of Erlianqiao. Other varieties ofgreenstone including basic tuff, gabbro and diabase dyke are also found. Although the size ofthe mass of greenstone is unclear, Mt. Dadingzishan, 5 km across, consists of a greenstonecomplex of an ophiolitic succession partly containing komatiite as was reported by Cui (1986).

Bedded chert formations, invariably displaying
an intraformational fold, are distributed in somequarries near Shichang, Yinhe and Shengli
Nongchang (Figure 1). They seem to compriseisolated blocks enclosed in clastic matrix. Sandstone and shale make no good exposures, because
they are no more resistant to weathering and economically less important than bedded chert or
limestone. A sandstone block about 2 m in diameter, gray medium-grained quartzo-feldspathic
wacke, occurs to the east of an exposure of
bedded chert at Shichang (JMP1429 in Figure 1).
A heavily weathered gray and reddish brownsiliceous shale with faint fissility crops out at asite about 15 km west of Shichang (the point of
JMP1320, etc. in Figure 1). Black manganese
nodules of 10 to 20 cm in diameter occur inassociation with the shale.
All the rock specimens, except for JMP1299,
treated for micropaleontological examination inthis paper were collected by the present authors
in the summer of 1986. Registered numbers ofrock specimens (JMP-) and sample numbers recorded in the field are listed below (see Figure
1 for localities of the samples).
JMP1299 (A-5-3): reddish brown bedded (?) chertoffered by Dr. Shao Ji An (Beijing Univ.). She informed us that this specimen is collected from thequarry near Shichang. (in the same location of
JMP1368 etc.)
JMP1320 (SM86080905): reddish brown siliceous shalewith faint fissility. (west of Shichang)
JMP1331 (SM86080906): greenish gray siliceous shalewith faint fissility. (west of Shichang)
JMP1332 (SM86080910): gray siliceous shale with faintfissility. (west of Schichang)
JMP1368 (SK86080708A): gray bedded chert. (Shichang)
JMP1369 (SK86080708B): reddish brown bedded chert.
(Shichang)
JMP1371 (SK86080708D): reddish brown bedded chert.
(Shichang)
JMP1429 (SM86080901): reddish brown bedded chert.
(Shichang)
JMP1431 (SK86080603A): gray bedded chert. (Yinhe)

Descriptions of Radiolaria
Since study of Mesozoic Radiolaria is still in
its infancy, the phylogeny and classification,
especially at the suprageneric level, have not been

844. Triassic and Jurassic Radiolaria from China
Table 1

259

List of Triassic and Jurassic Radiolaria from the Nadanhada Range, Northeast China. Localities ofstandard samples are shown in Figure 1.
SAMPLE NUMBER (JMP-)

1299 1368 1369 1371 1429 1431 1320 1331 1332

Acanthocircus sp.
Capnodoce trauersi

X

C.

sp.

X

Capnuchosphaera(?) sp.
Eptingium sp.

X

Eucyrtis(?) sp.
Liuarella ualidus
Parahsuum(? ) sp. A
Penlaclinocarpus sp. A
Plafkerium sp.
Poulpus curuispinus
Pseudoheliodiscus sp.
Pseudostylosphaera japonica
cf .hellenicaP.
cf.tenue
P.
P.
P.
P.
P.
P.

sp.A
sp.B
sp.C
sp.D
sp.E

X
X
X

X
X

X

X
X
X
X

X

X
X
X

X
X
X

X
X
X
X
X
X
X

sp.
P. (?)
Silicarmiger sp.
Triassocampe deweueri
sp. A
T.
sp.
T.

X
X

X

X

X

X
X

X

sp.
T. (?)
Xiphosphaera(? ) sp.
Yeharaia annulata
japoni ca
Y.

X

Y.
Y.

sp. A
sp.

X

Ristola(?) sp.
Stichocapsa conuexasp.
S. (?)
Thanarla(?) sp.
Tr i co I ocapsa pi icarum

X

X
X
X

X

Unnamed Nassellaria

X
X

X
X
X

X

X
X
X
X
X

X

X

X

X

X

X

tetragona
cf . rues t i

fusiformis

X

X
X
X

sp.

Guexella nudata
Hsuum sp.
Pantanellium sp.
Protunuma sp.

T.
T.
T. (?)

X
X
X
X
X

X

Archaeodi c tyomi t ra sp.
Canoptum sp.
Dictyomi trella(?) sp.
Eucyrtidiellum ptyctum
unumaense
E.

E.

X

X
X

Satoru KOJIMA and Shinjiro MIZUTANI

260

established so far. In this paper, we describe theRadiolaria in alphabetical order of the genus
name for convenience. All the species describedherein are illustrated in Figures 2-5. The fossil
individuals used in the description and figures
are numbered, for example, as (12345/6789);
the numerator represents a sequential numberof SEM photograph and the denominator indicates that of the rock specimen (JMP numbers
shown in Figure 1 and Table 1) from which agiven fossil was extracted. Both of these numbers
are registered in the Rad File, Department ofEarth Sciences, Nagoya University.
Genus Capnodoce De Wever, 1979

Capnodoce traversi Pessagno, 1979
Figure 3-13
Capnodoce traversi Pessagno, 1979, p. 176, 177, pI. 1,
figs. 11, 12; Blome, 1983, p. 36, pI. 8, figs. 4, 16;
Blome, 1984, p. 35, pI. 4, fig. 19.

Genus Eucyrtidiellum Baumgartner, 1984

Eucyrtidiellum ptyctum (Riedel and Sanfllippo,
1974)
Figures 4-12, 13
Eucyrtidium ptyctum Riedel and Sanfilippo, 1974,
p. 778, pI. 5, fig. 7, pI. 12, fig. 14; Baumgartner andBernoulli, 1976, p. 617, rigs. lIe, g; Baumgartner
et aZ., 1980, p. 53, pI. 3, fig. 13; Aita, 1982, pI. 2,
figs. 8-9b; Nishizono et aZ., 1982, pI. 2, fig. 12; Yao,
1984,pl. 2,fig. 30.
Eucyrtidiellum ptyctum (Riedel and Sanfilippo), Baumgartner, 1984, p. 764, pI. 4, figs. 1-3; Matsuoka,
1986a, pI. 2, fig. 10; Nagai, 1986, p. 14, 15, pI. 2,
fig. 7.
Eucyrtidium(?) ptyctum Riedel and Sanfilippo, Pessagno, 1977, p. 94, pI. 12, fig. 7; Mizutani, 1981,
p. 182, pI. 64, figs. la-2; Adachi, 1982, pI. 3, figs.
7, 8; Mizutani et al., 1982, p. 57, pI. 4, fig. 5; Ishida,
1983, pI. 9, fig. 4; Nishizono and Murata, 1983, pI. 4,
fig. 7; Yamamoto, 1983,pI.1,fig.4;Takashimaand
Koike, 1984, pI. 2, fig. 5; Aita, 1985, fig. 7-14;
Ishida, 1985a, pI. 3, fig. 15; Matsuoka and Yao,
1985, pI. 2, fig. 8; Matsuoka and Yao, 1986, pI. 2,
fig. 10; Tanaka et aZ., 1985, pI. 1, fig. 16; Aita andOkada, 1986, p. 109, pI. 6, figs. 14-17, pI. 7, figs.
3a, b.
"Eucyrtidium" ptyctum Riedel and Sanfilippo, Pessagno
et al., 1984, p. 30, 31, pl. 4, figs. 12-14.

Eucyrtidiellum unumaense (Yao, 1979)
Figure 4-16
Eucyrtidium(?) unumaensis Yao, 1979, p. 39, pI. 9, figs.
1-11; Sugano et aZ., 1980, pI. 4, fig. 3; Kido et al.,
1982, pI. 4, fig. 9; Kojima, 1982, pI. 1, fig. 11;
Matsuoka, 1982, pl. 1, rig. 15; Owada and Saka,
1982, pI. 2, fig. 8; Sashida et al., 1982, pI. 2, fig. 3;
Wakita, 1982, pI. 3, fig. 1; Wakita and Okamura,
1982, pI. 8, fig. 7; Yao et aZ., 1982, pI. 3, fig. 7; Saka
1983, pI. 5, figs. 6, 7; Aita, 1985, figs. 7-15, 16;
Yamamoto, 1985, pl. 2, fig. 4.
Eucyrtidiellum unumaensis (Yao), Baumgartner, 1984,
p. 765, pI. 4, fig. 6; Yamamoto et al., 1985, p. 35,
pl. 4, fig. 6; Ishida, 1986, pl. 1, fig. 6; Nagai, 1986,
p.13, 14,pI.1,figs. la-c, pI. 2, fig. 1.
Stichocorys sp. Ichikawa and Yao, 1973, pl. 1, figs.
3-4b.
Eucyrtidium(?) unumaense Yao, Mizutani et al., 1984,
pI. 1, fig. 8; Ishida, 1985b, pI. 2, fig. 27; Matsuoka,
1985, pI. 1, fig. 9.

Genus Guexella Baumgartner, 1984

Guexella nudata (Kocher, 1980)
Figures 4-9,10
Lithocampe nudata Kocher in Baumgartner et aZ., 1980,
p. 55, pI. 6, fig. 3.
Guexella nudata (Kocher), Baumgartner, 1984, p. 766,
767, pI. 5, figs. 5 -7; Yamamoto et aZ., 1985, p. 35,
pI. 4, fig. 7; Kishida and Hisada, 1986, fig. 8-3;
Matsuoka, 1986a, pI. 3, figs. 15a, b.
Lithocampe(?) nudata Kocher, Aita, 1982, pI. 1, figS.
19a-c; Matsuoka, 1982, pl. 2, figs. 1,2; Yao etaZ.,
1982, pI. 4, figs. 1,2; Koike and Takashima, 1983,
pI. 1, fig. 7; Matsuoka, 1983a, p. 27, pI. 9, figs. 1214; Matsuoka, 1983b, fig. 4-10; Takashima andKoike, 1984, pI. 1, fig. 20; Yao, 1984, pI. 2, fig. 1;
Aita, 1985, fig. 7-17; Ishida, 1985a, pI. 3, fig. 13.

Genus Livarella Kozur and Mostler, 1981

Livarella validus Yoshida, 1986
Figures 3-18a, b
Livarella validus Yoshida, 1986, p. 14, pI. 3, figS. 1-3.

GenusParahsuum Yao, 1982
Parahsuum(?) sp. A
Figure 3-10

Description:- Test conical and cylindricaldistally. Cephalis trapezoidal, poreless, without

844.

Triassic and Jurassic Radiolaria from China

apical horn. Proximal one-third to one-fifth of
the test poreless, the rest covered by irregularly
pored meshwork.
Remarks:-Parahsuum Yao (I982) was originally described as follows: "Shell multisegmented, conical to spindle-shaped lacking welldeveloped strictures. Cephalis conical to domeshaped, poreless with or without apical horn.
Thorax trapezoidal in outline with sparse irregulary displaced pores. Abdomen and postabdominal segments with continuous edged
costae. Single row of square pore frames withcircular, primary pores between costae." We
tentatively treat this form under the genus
Parahsuum based on the external features of thetest. Although none of our six specimens has
apical horn, this species might originally have
had an apical horn, judging from the abrupt
termination and the irregular upper surfaceof the cephalis.
Genus Pentactinocarpus Dumitrica, 1978
Pentactinocarpus sp. A
Figure 2-13

Description :-Shell spherical with hexagonalpore frames. Pore frames with small nodes atvertices. Apical spine short, and basal spines
connected at their proximal parts with poreframes.
GenusPoulpus De Wever, 1979
Poulpus curvispinus Dumitrica, Kozur andMostler,1980
Figure 2-16

Poulpus curvispinus Dumitrica et al., 1980, p. 22, pI. 2,
fIg. 1, pI. 15, figs. 5, 6.
Poulpus sp. aff. P. curvispinus Dumitrica et al., Yao,
1982, pI. 1, fig. 18.

Remarks:-Although the internal cephalicstructure of this specimen cannot be observed
because of secondary fillings, this specimen
seems to be assignable to P. curvispinus, judging
from characteristic shape of cephalis and feet.
Genus Pseudostylosphaera Kozur and261

Mostler, 1981
Remarks :-Archaeospongoprunum Pessagno(I973) is originally described as a spongurid withspongy meshwork shell and two triradiate or
tetraradiate polar spines, and De Wever et al.,(I979), and Nakaseko and Nishimura (1979)
included some Triassic spumerallian Radiolaria
in this genus. Subsequently, Kozur and Mostler(1981) proposed a new genusPseudostylosphaera,
and included in it some species which were described under the genus Archaeospongoprunum.
We use this new generic name in this paper,
although it is not clear whether our specimens
have the inner structure characteristic of thegenus.
Pseudostylosphaera japonica (Nakaseko andNishimura, 1979)
Figure 2-1

Archaeospongoprunum japonicum Nakaseko and Nishimura, 1979, p. 67,68, pI. 1, figs. 2,4,9; Mizutani
and Koike, 1982, pI. 3, fig. 3; Yao, 1982, pI. 1,
fig. 21; Adachi and Kojima, 1983, pI. 13, fig. 10;
Yoshida, 1986, pl. 9, figs. 1,2.
Pseudostylosphaera japonica (Nakaseko and Nishimura),Lahm, 1984, p. 34, pI. 4, figs. 9, 10; Kishida and
Hisada, 1986, fig. 3-4.
Stylosphaera(?) japonica (Nakaseko and Nishimura),
Kishida and Sugano, 1982, pI. 1, figs. 10-15;

Remarks:-The holotype of Pseudostylosphaera japonica (Nakaseko and Nishimura)(1979, pI. 1, fig. 2) and that of P. japonica ofLahm (1984, pI. 4, figs. 9, 10) slightly differ
from our present specimen in having more constricted polar spines in their proximal portions.
Other examples of P. japonica of Nakaseko andNishimura (1979, pI. 1, figs. 4, 9), however, arevery similar to our specimen, and we tentatively
assigned this form to P. japonica.
Pseudostylosphaera sp. cf. P. hellenica(De Wever, 1979)
Figure 2-4

Archaeospongoprunum hellenicum De Wever? ,1982,
p. 179, 180, pI. 10, fig. 5.
cf. A rchaeospongoprunum (? ) hellenicum De Weveret al., 1979, p. 78, pI. 1, fIg. 8.

262

SatolU KOJIMA and Shinjiro MIZUTANI

844. Triassic and Jurassic Radiolaria from China
cf. Archaeospongoprunum hellenicum De Wever, 1982,
p. 179,180, pI. 10, fig. 4.
cf. Stylosphaera? cf. hellenica (De Wever), Kozur and
MosUer, 1979, p. 55, pI. 1, fig. 4, pI. 17, fig. 4.
cf. Pseudostylosphaera hellenica (De Wever), Lahm,
1984, p. 35, pI. 5, figs. 1,2.

Pseudostylosphaera sp. cf. P. tenue(Nakaseko and Nishimura, 1979)
Figure 2-5
cf. Archaeospongoprunum tenue Nakaseko and Nishimura, 1979, p. 68,69, pI. 1, figs. 8, 10; Mizutani and
Koike, 1982, pI. 3, fig. 2;Adachi and Kojima, 1983,
pI. 13, fig. II.
cf. Pseudostylosphaera tenue (Nakaseko and Nishimura);Lahm, 1984, p. 36, pI. 5, figs. 5, 6.

Pseudostylosphaera sp. A
Figure 2-2

263

abruptly near the terminations.

Pseudostylosphaera sp. C
Figure 2-7

Description :-Shell slender, ellipsoidal withmeshwork, and has a circumferential sulcus. Polarspines sturdy, triradiate in cross section, andslightly twisted.
Pseudostylosphaera sp. D
Figure 2-8

Description :-Shell sub spherical to ellipsoidal
with spongy meshwork. Two opposite polar
spines triradiate in cross section, three wide
grooves alternating with three narrow ridges
displaying a strong tortion.

Description :-Shell elliptical with spongy
meshwork. Two opposite polar spines short,wide, equal in length and triradiate in cross section; three wide grooves alternating with three
narrow ridges.
Remarks:- The present specimen differs fromother species of Pseudostylosphaera in having
wide polar spines.

Description :-Shell cylindrical, covered bypolygonal meshwork with small nodes. Two opposite polar spines unequal in length; shorter one
twisted and triradiate in cross section, whereas
longer one not twisted and tetraradiate.

Pseudostylosphaera sp. B

Genus Stichocapsa Haeckel, 1881

Figure 2-3

Stichocapsa convexa Yao, 1979

Description :-Shell subglobular with twopolar spines. These spines have three narrowridges alternating with relatively wide grooves,and are twisted distally. The width of the spines
is constant in much of the length and decreases

Figure 4-2

Pseudostylosphaera sp. E
Figure 2-10

Stichocapsa convexa Yao, 1979, p. 35, 36, pl. 5, figs.
14-16, pI. 6, figs. 1-7; Aita, 1982, pI. 1, figs. 6-7b;
Wakita, 1982, pI. 3, fig. 7; Koike and Takashima,
1983, pI. 1, fig. 12; Nishizono and Murata, 1983, pI.

~ Figure 2.
Middle Triassic Radiolaria from the Nadanhada Range.
1. Pseudostylosphaera japonica (Nakaseko and Nishimura) (40278/1368) scale bar = 110/Lm. 2. Pseudostylosphaera sp. A (42219/1368) scale bar = 120 /Lm. 3.Pseudostylosphaera sp. B (41992/1368) scale bar = 210 /Lm.
4. Pseudostylosphaera sp. cf. P. hellenica (De Wever) (40275/1368) scale bar = 180 /Lm. 5. Pseudostylosphaera sp.
cf. P. tenue (Nakaseko and Nishimura) (42215/1368) scale bar = 210 /Lm. 6. Pseudostylosphaera (?) sp. (42220/
1368) scale bar = 120 /Lm. 7. Pseudostylosphaera sp. C (42213/1368) scale bar = 120 /Lm. 8. Pseudostylosphaera
sp. D (42216/1368) scale bar = 210/Lm. 9. Pseudostylosphaera (?) sp. (40319/1369) scale bar = 77 /Lm. 10.
Pseudostylosphaera sp. E (40286/1368) scale bar = 180 /Lm. 11. Xiphosphaera (?) sp. (40345/1369) scale bar =77 /lm. 12. Eptingium sp. (40325/1369) scale bar = 110 /lm. 13. Pentactinocarpus sp. A (40340/1369) scale bar= 110 /lm. 14. Pseudoheliodiscus sp. (40266/1368) scale bar = 110/lm. 15. Plajkerium sp. (42000/1368) scalebar = 210 /lm. 16. Poulpus curvispinus Dumitrica et al. (40332/1369) scale bar = 77 /lm. 17. Silicarmiger sp.
(42008/1368) scale bar = 120 /lm. 18. Eucyrtis (?) sp. (40288/1368) scale bar = 77 /lm.

264

Satoru KOJIMA and Shinjiro MIZUTANI

844. Triassic and Jurassic Radiolaria from China4, fig. 5; Baumgartner, 19114, p. 785, pI. 8, fig. 19;
Matsuoka, 1985, pI. 1, fig. 8; Yamamoto et al., 1985,
p. 38, pI. 7, fig. 4; Takemura, 1986, p. 55, pI. 7,
figs. 9, 10;Yokota and Sano, 1986, pI. 1, fig. 4.
"Stichocapsa" sp. B, Ichikawa and Yao, 1973, pl. 3,
figs. 3-5.
Stichocapsa sp. J, Aita, 1982, pI. 1, figs. 8-9b.

265

Dietyomitrella sp. A De Wever et al., 1979, p. 90, pI. 5,
figs. 12, 16.

Remarks:- This form is different from T.
deweveri in having one row of pores below eachcircumferential ridge.
Genus Tricolocapsa Haeckel, 1887

Genus Triassocampe Dumitrica, Kozur andMostler, 1980

Triassocampe deweveri (Nakaseko andNishimura, 1979)
Figures 3-2, 3

Dictyomitrella deweveri Nakaseko and Nishimura, 1979,
p. 77,pl.l0, figs. 8,9.
Triassocampe deweveri (Nakaseko and Nishimura, 1979),
Mizutani et al., 1982, p. 55, 56, pi: 4, fig. 1; Yao,
1982, pI. 1, figs. 1-3; Yao et al., 1982, pI. 1, fig. 1;
Yao, 1983, fig. 2-1; Kishida and Hisada, 1986, fig.
3-2.
Triassoeampe sealaris Dumitrica et al., 1980, p. 26, pI. 9,
figs. 5, 6, 11, pI. 14, fig. 2; Mizutani and Koike,
1982, pI. 4, fig. 4.

Remarks:-Triassocampe scalaris (Dumitrica
et al., 1980) has common characteristics with
Triassocampe deweveri (Nakaseko and Nishimura), and is regarded as a synonym. Although
Nakaseko and Nishimura (1979, p. 77) remarked
that the Dictyomitrella deweveri "appears to be
identical with Dictyomitrella sp. A of De Wever(1979, p. 90, pI. 5, figs. 12, 16)", the latter isdistinguished from the former by having only
one row of pores below circumferential ridges.

Triassocampe sp. A
Figure 3-1

Tricolocapsa(?) fusiformis Yao, 1979
Figures 4-3, 4

Trieoloeapsa(?) fusiformis Yao, 1979, p. 33,34, pI. 4,
figs. 12-18, pI. 5,figs.I-4;Kido etal., 1982,p1.5,
fig. 3; Matsuoka, 1982, pI. 1, figs. 17-19;Wakita,
1982, pI. 3, fig. 4; Wakita and Okamura, 1982, pl. 7,
fig. 10; Adachi and Kojima, 1983, pI. 16, fig. 5;
Kashima, 1983, pI. 8; fig. 4; Matsuoka, 1983a, p. 19,
pI. 2, fig. 11, pI. 8, fig. 1; Takashima and Koike,
1984, pI. 1, fig. 12; Ishida, 1985a, pI. 5, fig. 13;
Matsuoka,1985,pl.l,fig. 3; Yamamoto, 1985,pI.2,
fig. 6; Ishida, 1986, pI. 1, fIg. 7; Takemura, 1986, p.
54, pI. 7, fig. 6; Yokota and Sano, 1986, pI. 1, fig. 7.

Tricolocapsa plicarum Yao, 1979
Figure 4-6

Tricolocapsa pliearum Yao, 1979, p. 32, 33, pI. 4, figs.
1-11;Aita, 1982, pI. 1, fig. 17; Kido etal., 1982, pI.
5, fig. 1; Kishida and Sugano, 1982, pI. 12, figs. 1,
2; Kojima, 1982, pI. 2, fig. 1; Nishizono et al., 1982,
pI. 2, fig. 16; Sashida et al., 1982, pI. 2, fig. 1;
Wakita, 1982, pI. 3, fig. 3; Wakita and Okamura,
1982, pI. 7, fig. 9; Yao et a/., 1982, pI. 3, fig. 12;
Adachi and Kojima, 1983, pI. 16, fig. 7; Kashima,
1983, pI. 9, fig. 1; Matsuoka, 1983a, p. 20, pI. 3,
figs. 1,2; Nishizono and Murata, 1983, pI. 4, fig. 4;
Saka, 1983, pI. 6, figS. 2-4; Takashima and Koike,
1984, pI. 1, fig. 9; Yao, 1984, pI. 2, figs. 11, 12;
Ishida, 1985a, pI. 3, fig. 12; Matsuoka, 1985, pI. 1,
figs. 1,2; Yamamoto, 1985, pI. 2, fig. 8; Yamamoto(- Figure 3. Middle and Upper Triassic Radiolaria from the Nadanhada Range.
1. Triassocampe sp. A (42221/1368) scale bar = 120 j.lm. 2. Triassoeampe deweveri (Nakaseko and Nishimura)(42224/1369) scale bar = 120 j.lm. 3. Triassoeampe deweveri (Nakaseko and Nishimura) (42225/1369) scale bar= 84 j.lm. 4. Triassoeampe sp. (41501/1431) scale bar = 77 j.lm. 5. Triassoeampe sp. (41499/1431) scale bar =110j.lm. 6. Triassoeampe (?) sp. (40262/1368) scale bar = 77 j.lm. 7. Yeharaia sp. (41921/1369) scale bar = 84 j.lm.
8. Yeharaia japoniea Nakaseko and Nishimura (41943/1369) scale bar = 84 j.lm. 9. Yeharaia arlnu/ata Nakaseko
and Nishimura (41919/1369) scale bar = 120 j.lm. 10. Parahsuum (?) sp. A (38972/1299) scale bar = 110 j.lm.
11. Yeharaia sp. A (41950/1369) scale bar = 84 j.lm. 12. CapnucllOsphaera(?) sp. (38929/1299) scale bar =110 j.lm. 13. Capnodoee traversi Pessagno (41479/1429) scale bar = 180 j.lm. 14. Capnodoee sp. (41480/1429)
scale bar = 110j.lm.15.Aeanthocireus sp. (38920/1299) scale bar = 180j.lm. 16. Aeanthocireus sp. (38967/1299)
scale bar = 110 j.lm. 17. Pseudoheliodiseus sp. (38971/1299) scale bar = 180 j.lm. 18a. Livarella validus Yoshida(38950/1299) scale bar = 110j.lm. 18b. Livarella validus Yoshida (38951/1299) scale bar = 110 j.lm. 19.Aeanthocireus sp. (40409/1371) scale bar = 120 j.lm. 20. Pseudoheliodiseus sp. (38990/1299) scale bar = 180 j.lm.

266

SatolU KOJIMA and Shinjiro MIZUTANI

844. Triassic and Jurassic Radiolaria from China

267

et al., 1985, p. 39, pi. 8, fig. 8; Ishida, 1986, pI. 1,
fig. 9; Matsuoka, 1986b, figs. 3-a-c; Sato et al.,1986, fig. 17-12; Yokota and Sano, 1986, pI. 1,
fig. 5.
"Artocapsa" sp. A, Ichikawa and Yao, 1973, pI. 5, figs.
la, b.

fig. 10; Kojima, 1982, pI. 2, fig. 5; Adachi andKojima, 1983, pI. 13, fig. 4, Ishida, 1984, pi. 1, figs.
13-15.
Triassocampe(?) annulata (Nakaseko and Nishimura),Yao, 1982, pl. 1, fig. 11; Yao et al., 1982, pI. 1, fig.
8;Yao, 1983,fig. 2-5.

Tricolocapsa tetragona Matsuoka, 1983

Yeharaia japonica Nakaseko andFigure 4-7

Nishimura, 1979

Tricolocapsa tetragona Matsuoka, 1983a, p. 22, 23, pI. 3,
figs. 8-12, pI. 8, figs. 4-10; Takashima and Koike,
1984,pl. 1,fig. l1;Satoetal., 1986,fig.17-18.
Tricolocapsa sp. N, Matsuoka, 1982, pI. 2, figs. 13,17.
Tricolocapsa sp. E, Aita, 1982, pI. 2, fig. 4

Figure 3-8
Yeharaiajaponica Nakaseko and Nishimura, 1979, p. 83,
pI. 10, figs. 6, 10, pl. 12, fig. 9; Ishida, 1984, pI. 1,
figs. 17-19.
Triassocampe(?) japonica (Nakaseko and Nishimura),Yao, 1982, pI. 1, fig. 12.

Tricolocapsa sp. cf. T. ruesti Tan Sin Hok, 1927
Figure 4-5

Yeharaia sp. A
Figure 3-11

Tricolocapsa sp. cf. T. rUsti Tan Sin Hok, Yao, 1979,
p. 30, 31, pI. 3, figs. 8-20; Adachi and Kojima,
1983, pI. 16, fig. 8; Kashima, 1983, pi. 9, fig. 10;
Ujiie and Hashimoto, 1983, fig. 5-5; Matsuoka, 1985,
pl. 1, fig. 5; Yamamoto et al., 1985, p. 39, pl. 9,
fig. 1; Ishida, 1986, pI. 1, fig. 10; Yokota and Sana,
1986, pI. 1, fig. 6.
"Hemicryptocapsa" sp. Ichikawa and Yao, 1973, pI. 4,
figs. 7a, b.
Tricolocapsa yaoi (Kozur), Takemura, 1986, p. 54, pI. 7,
figs. 5, 7,8.
cf. Tricolocapsa rUsti Tan Sin Hok, 1927, p. 50, pI. 9,
fig. 65.

Genus Yeharaia Nakaseko and Nishimura, 1979

Yeharaia annulata Nakaseko andNishimura, 1979
Figure 3-9

Triassocampe(?) sp. A, Mizutani et al., 1982, p. 56, pI.
4, fig. 2.
Triassocampe(?) sp. F, Yao, 1982, pi. 1, fig. 10; Yao etal., 1982, pI. 1, fig. 9.

Description:-Test conical to cylindrical withseven to eight, sometimes more, segments.
Cephalis hemispherical with apical hom and twolaterally extending spines in the same plane.
Thorax, abdomen and three post abdominal
chambers, all trapezoidal in external form, havebroad ridges between them; the chambers have
one row of pore on their ridges. Distal segments
have more prominent and narrow ridges.
Remarks:- This form is distinct from otherspecies of Yeharaia in having cephalis with twolaterally extending spines.

Yeharaia annulata Nakaseko and Nishimura, 1979, p. 82,
83, pI. 10, figs. 1,7, pI. 12, fig. 5; Kido, 1982, pI. 1,+-- Figure 4. Middle Jurassic Radiolaria from the Nadanhada Range.
1. Stichocapsa(?) sp. (40015/1331) scale bar = 51 j.lm. 2. Stichocapsa convexa Yao (42066/1331) scale bar =84 j.lm. 3. Tricolocapsa (?) fusiformis Yao (40024/1331) scale bar = 51 j.lm. 4. Tricolocapsa (?) fusiformis Yao(39862/1320) scale bar = 56 j.lm. 5. Tricolocapsa sp. cf. T. ruesti Tan Sin Hok (40054/1331) scale bar = 77 j.lm.
6. Tricolocapsa plicarum Yao (42211/1331) scale bar = 84 j.lm. 7. Tricolocapsa tetragona Matsuoka (40038/1331)
scale bar = 77 j.lm. 8. Stichocapsa (?) sp. (39983/1331) scale bar = 42 j.lm. 9. Guexella nudata (Kocher) (40059/
1331) scale bar = 51 j.lm. 10. Guexella nudata'(Kocher)(40030/1331) scale bar = 51 j.lm. 11. Unnamed Nassellaria(40053/1331) scale bar = 51 j.lm. 12. Eucyrtidiellum ptyctum (Riedel and Sanfilippo) (39996/1331) scale bar= 51 j.lm. 13. Eucyrtidiellum ptyctum (Riedel and Sanfilippo) (40060/1331) scale bar = 40 j.lm. 14. Eucyrtidiel.
lum sp. (40037/1331) scale bar = 51 j.lm. 15. Eucyrtidiellum sp. (40043/1331) scale bar = 51 j.lm. 16. Eucyrtidiellum unumaense (Yao) (42015/1331) scale bar = 56 j.lm.

268Satoru KOJIMA and Shinjiro MIZUTANI

Figure 5. Middle Jurassic Radiolaria from the Nadanhada Range.
1. Canoptum sp. (40016/1331) scale bar = 110 /-1m. 2. Ristola(?) sp. (40046/1331) scale bar = 77 /-1m. 3. Die·tyomitrella (?) sp. (40044/1331) scale bar = 77 /-1m. 4. Protunuma sp. (39848/1320) scale bar = 84/-1m. 5. Arehaeodietyomitra sp. (39984/1331) scale bar = 84 /-1m. 6. Arehaeodietyomitra sp. (40040/1331) scale bar = 77 /-1m.
7. Arehaeodietyomitra sp. (42027/1331) scale bar = 84/-1m. 8. Archaeodietyomitra sp. (42013/1331) scale bar= 56 /-1m . 9. Thanarla(?) sp . (42016/1331) scale bar = 56/-1m . 10. Hsuum sp. (40071/1332) scale bar = 77 /-1m.
11. Hsuum sp. (42036/1331) scale bar = 84 /-1m. 12 . Pantanellium sp. (39840/1320) scale bar = 56 /-1m.

844. Triassic and Jurassic Radiolaria from China
Discussion(A) Age of Radiolaria-bearing rocks in the
Nadanhada Range
The bedded chert sequence in the Nadanhada
Range (JMP1299, 1368, 1369, 1371, 1429 and
1431, Table 1) yields Triassic Radiolaria. Sample
of JMP 1369 (Figure 1, Table 1) bears Eptingium
sp., Poulpus curvispinus, Pseudostylosphaera
japonica, Triassocampe deweveri, Yeharaia annulata, Y. elegans, Y. japonica, Y. sp. A, etc. These
species are characteristic of the Triassocampe
deweveri Assemblage of Yao (1982), which is
assigned to Ladinian (late Ladinian and earlier)based on such coexisting conodonts as Gladigondolella tethydis (Huckriede) and Carin ella hungarica (Kozur and Vegh). Pseudostylosphaera japonica was also reported by Lahm (1984) from theupper Anisian to Ladinian section in the Recoaro
area, northern Italy. Poulpus curvispinus was
described from the middle Triassic Buchenstein
Formation (probably near the boundary ofAnisian and Ladinian) by Dumitrica et al. (1980).
Sample JMP1368 seems to be approximately of
the same age with JMP1369, judging from theoccurrence of Poulpus curvispinus, Pseudostylosphaera japonica and Triassocampe deweveri;
but JMP1369 yields several species of Yeharaia,
whereas JMP1368 is characterized by carrying
many species of Pseudostylosphaera. The abovementioned evidence indicates that samples
JMP1368 and 1369 are middle Triassic in age,probably late Anisian to Ladinian. Triassic age ofsample JMP1431 might be indicated by theoccurrence of Triassocampe sp. (Figures 3-4, 5),although most of Radiolaria from the sample are
too poorly preserved to be identified.
Sample JMP1299 yields Capnodoce sp.,
Capnuchosphaera(?) sp., Livarella validus andPseudoheliodiscus sp. The two genera, Capnodoce and Capnuchosphaera were first describedby De Wever et al. (1979) from Carnian toNorian formations in Greece, Sicily and Turkey.
Pessagno et al. (1979), Blome (1983) and Blome(1984) have studied a late Triassic radiolarianbiostratigraphy in western North America, andlimited the occurrence of the above-mentioned269

two genera within the upper Triassic (from upper
Carnian to upper middle Norian). Yoshida(1986) examined a bedded chert sequence ofTriassic to Jurassic age in the Mino terrane,
Southwest Japan, and subdivided it into sevenradiolarian zones. Livarella validus is recognizedin his Livarella-Canoptum Zone, which is supposed to be early to middle Rhaetian in age bycomparing with the radiolarian zonation by Yao(\982) and Blome (1984) and the data of Kozur
and Mostler (\981). Taking these lines of evidence into account, age of the rock, JMP 1299,
is correlative with a zone between Carnian to
Rhaetian, and probably late Carnian to Norian.
Sample JMP1429 also bears Capnodoce, and isoflate Triassic age.
Jurassic Radiolaria are obtained from asiliceous shale (JMPI320, 1331 and 1332, Table
1) distributed to the west of Shichang (Figure 1).
Sample JMP1331 yields well-preserved Radiolaria,
such as Eucyrtidiellum ptyctum, E. unumaense,
Guexella nudata, Ristola(?) sp., Stichocapsa convexa, Tricolocapsa plicarum, T. tetragona and T.
(?) fusiform is. Baumgartner (I 984) reviewed
many radiolarian biostratigraphic works, including his own, on the Tethyan middle Jurassic toearly Cretaceous. In his range chart Guexella
nudata and Eucyrtidielum ptyctum occur fromlate Bathonian to early Oxfordian and middle Callovian to late Tithonian, respectively. Matsuoka
and Yao (1986) examined a Jurassic radiolarianbiostratigraphy of Southwest Japan, and proposed eight radiolarian zones bounded by biohorizons based on the first ( or last) appearance
or the first evolutionary appearance of characteristic radiolarian species. Coexistence of
Tricolocapsa tetragona, Guexella nudata andEucyrtidiellum ptyctum is restricted to the
middle part of the Tricolocapsa conexa Zone
assigned to the late Middle Jurassic according totheir zonation. Yamamoto et al. (1985) examined middle Callovian Radiolaria in a deep-sea
core sample recovered from the Atlantic ocean
bottom of the Blake Bahama Basin (Leg 76534A-126-1). The age of this sample was determined by nannofossils and dinoflagellates. The
Radiolaria from that core have some genera and270

Satoru KOJIMA and Shinjiro MIZUTANI

species common to those of sample JMP 1331 ;they are Canoptum sp., Eucyrtidiellum unumaense, Guexella nudata, Stichocapsa convexa,
Tricolocapsa plicarum and T. cf. ruesti. All thesedata suggest that sample JMP1331 is of middle
Jurassic age, and probably Bathonian or Callovian. Samples of JMP1320 and 1332 contain
Radiolaria common to sample JMP133 I andseem to be middle Jurassic in age, although theylack diagnostic species.
(B) Pantanellium deficiency problem
Faunal realms and provinces of middle andlate Jurassic Radiolaria are discussed by Pessagno
and Blome (1986) and Pessagno et al. (1986,
1987) in the course of their Jurassic radiolarianbiostratigraphic works in western North America
and Mexico. They differenciated the radiolarianassemblage of the Tethyan Realm from that of
the Boreal Realm; these realms are verified by
the realms of calpionellids, ammonites andBuchia. Among the Radiolaria which characterize
the faunal realms, pantanelliid abundance/
diversity conspicuously declines from the Tethyan Realm to the Boreal Realm.
Although about 350 radiolarian individuals
were extracted from the siliceous shale of
JMP1331 and examined under the SEM, thissample is lacking in pantanelliids completely.
From the Nadanhada Range, more than 700
middle Jurassic Radiolaria are picked up for the
SEM study, and the only one skeleton of Pantanellium, shown in Figure 5-12, was extracted
from sample JMP1320. Pessagno et al. (1987,
p. 5-7) recommended to use the radiolarianfauna extracted from limestones, when comparative studies of radiolarian provincialities havebeen done. It is thought, however, that pantanelliid have tests sufficiently sturdy to be preserved not only in limestones but also in siliceous
shales. The radiolarian fauna in sample JMP 1331
is so abundant and well-preserved that Pantanellium, if present, must be preserved in therock record. There is little possibility that thepantanelliid tests were selectively removed fromthe site of sedimentation, because shales in the
Mino terrane with similar lithology and sedimen-

tary structure with that in the Nadanhada terranehave abundant pantanelliid Radiolaria. Thus,
the pantanelliid deficiency in the specimens in
the Nadanhada terrane results not from selective
destruction of pantanelliid tests but from theprovinCiality of pantanelliid Radiolaria.
Middle Jurassic siliceous shales widely distributed in the Mino terrane of Japan containabundant and diversified pantanelliids. According
to Hirooka et al. (1983), paleomagnetic inclinations indicate that middle Jurassic siliceous shalesin the Mino terrane were originally laid down
within 12° north or south of the Jurassic paleoequator. Although we have no paleomagnetic
evidence on the Radiolaria-bearing rocks in the
Nadanhada Range at present, middle Jurassic
siliceous shale (JMP1331 etc.) might have been
deposited considerably far north from the siteof deposition of coeval rocks in the Mino terrane,or the radiolarian fauna in the shales might bestrongly controlled by an ancient ocean current
which effectively linked the Nadanhada Range as
far away as to the Brooks Range of Alaska.
Acknowledgments
The present authors wish to thank the following Chinese geologists, Shao Ji An (Beijing University), Zhang Qing Long (Nanjing University)and Kang Bao Xiang (Geological Survey of
Heilongjiang Province) for their helps and discussions given to us during our field investigation.
Wang Cheng Yuan (Nanjing Institute of Geology
and Paleontology, Chinese Academy of Science)kindly informed us his latest works on Triassic
conodonts, when we have seen him at Dongfanghong, and Cui Xiu Shi (Geological Survey of
Heilongjian Province) showed us his recent
petrographic study on komatiite in the ophiolitecomplex during our stay in Haerbin. Field surveyof this study was financially supported by the
Grant-in-Aid for Overseas Scientific Survey of
the Japanese Ministry of Education, Science andCulture (Project No. 61042007 and 62041041).

844. Triassic and Jurassic Radiolaria from China
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Committee (Li, C. Y. et al.) eds., Contributions to
the project of plate tectonics in northern China,
p. 199-207, pis. 1-2, Geol. Pub. House, Beijing

271(in Chinese with English abstract).
De Wever, P. (1982): Radiolaires du Trias et du Lias dela Tethys (Systematique, Stratigraphie). Soc. Geol.
Nord, no. 7, p. 1-599, pis. 1-58 (in French withEnglish summary).
- - , Sanfilippo, A., Riedel, W. R. and Gruber, B.
(1979): Triassic radiolarians from Greece, Sicily
and Turkey. Micropaleont., v. 25, p. 75-110, pis.
1-7.
Dumitrica, P. (1978): Triassic Palaeoscenidiidae andEntactiniidae from the Vicentinian Alps (Italy) andeastern Carpathians (Romania). D. S. Inst. Geol.
Geofiz., Paleont., v. 64, p. 39-54, pis. 1-5.
- - , Kozur, H. and Mostler, H. (1980): Contribution
to the radiolarian fauna of the Middle Triassic of
the Southern Alps. Geol. Paliiont. Mitt. Innsbruck,
v.l0,p.I-46,pls.1-15.
Feng, Y. M. and Yang, Y. Q. (1984): Chaotic geologicalbodies in China. Bull. Chin. Acad. Sci., no. 10, p.
77-92, pI. 1 (in C~inese with English abstract).
Haeckel, E. (1881): Entwurf eines Radiolarien-Systems
auf Grund von Studien der Challenger-Radiolarien.
Jena. Z. Naturw., v. 15 (New Ser., v. 8), p. 418472 (in German with Latin description).
- - (1887): Report on the Radiolaria collected by
H.M.S. Challenger during the years 1873-1876.
Rept. Sci. Results Voyage H.M.S. Challenger, Zool.,v.18, p. i-clxxxviii and 1-1803, pis. 1-140.
Han, J. X. (1982): Middle and Upper Carboniferous
fusulinids from the Nadanhada range, Heilongjiang
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pis. 1-2 (in Chinese with English abstract).
--(1985): Early Permian fusulinids of the Nadanhada
range. Ibid., v. 24, p. 680-687, pis. 1-2 (inChinese with English abstract).
Hirooka, K., Nakajima, T., Sakai, H., Date, T., Nittamachi, K. and Hattori, 1. (1983): Accretion tectonics inferred from paleomagnetic measurementsof Paleozoic and Mesozoic rocks in central Japan.
In Hashimoto, M. and Uyeda, S. eds., Accretion
tectonics in the circum-Pacific regions, p. 179194, Terra Sci. Pub. Comp., Tokyo.
Howell, D. G., Jones, D. L. and Schermer, E. R. (1985):
Tectonostra tigraphic terranes of the circum-Pacificregion. In Howell, D. G. ed., Tectonostratigraphic
terranes of the circum-Pacific region, p. 3-30, Circum-Pacific Council Energy Miner. Res., Houston.
Ichikawa, K. and Yao, A. (1973): Scanning electron
microscope studies of pores of some cyrtoid radiolarians. Jour. Geosci., Osaka City Univ., v. 16, p.
125-144,pls.I-7.
Ishida, K. (1983): Stratigraphy and radiolarian assemblages of the Triassic and Jurassic siliceous sedimen tary rocks in Konose Valley, Tokushima Prefecture, Southwest Japan. - Studies of the South
Zone of the Chichibu Belt in Shikoku, part IV -.
Jour. Sci., Univ. Tokushima, v. 16, p. 111-141,

272

Satoru KOJIMA and Shinjiro MIZUTANI

pis. 1-12 (in Japanese with English abstract).
--(1984): The order of appearance of some radiolarians in Anisian bedded-chert bodies in the South
Zone of the Chichibu Belt, eastern Shikoku. Ibid.,
v. 17, p. 15-29, pis. 1-2 (in Japanese with English
abstract).
--(1985a): Radiolarian and conodont ages of thesedimentary bodies and their spatial arrangementin the South Zone of the Chichibu Belt in Tokushima Prefecture. - Studies of the South Zone of
the Chichibu Belt in Shikoku, part V -. Ibid., v.
18, p. 27-81, pis. 1-6 (in Japanese with English
abstract).
--(1985b): Pre-Cretaceous sediments in the southern
North Zone of the Chichibu Belt in Tokushima
Prefecture, Shikoku. Jour. Geol. Soc. Japan, v. 91,
p. 553-567, pis. 1-3 (in Japanese with English
abstract).
--(1986): Discovery of Jurassic radiolarians from the''Sambosan Group" at Hitsuzan, Kochi City,
Shikoku and its significance. Ibid., v. 92, p. 159161, pI. 1 (in Japanese).
Jones, D. L., Silberling, N. J. and Hillhouse, J. (1977):
Wrangellia - A displaced terrane in northwestern
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Kashima, N. (1983): Geology of the aqueduct tunnel
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project. part 1). Ehime Chigaku (Geology of
Ehime), Mem. Vol. Prof M. Miyahisa, p. 169-176,
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Kido, S. (1982): Occurrence of Triassic chert andJurassic siliceous shale at Kamiaso, Gifu Prefecture,
central Japan. News of Osaka Micropaleont., Spec.
Vol., no. 5, p.135-15I. pis. 1-5 (in Japanese withEnglish abstract).
- - , Kawaguchi,I.,Adachi,M. and Mizutani,S. (1982):
On the Dictyomitrella (?) kamoensis-Pantanellium
foveatum Assemblage in the Mino area, central
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Kishida, Y. and Hisada, K. (1986): Radiolarian assemblages of the Sambosan Belt in the western part of
the Kanto Mountains, central Japan. Ibid., no. 7,
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--and Sugano, K. (1982): Radiolarian zonation ofTriassic and Jurassic in outer side of Southwest
Japan. Ibid., no. 5, p. 271-300, pis. 1-12 (inJapanese with English abstract).
Koike, T. and Takashima, K. (1983): Stratigraphy andgeologic structure of the Paleozoic-Mesozoic rocks
in the upper-reach area of the Kuriugawa, Minamisaku-gun, Nagano Prefecture. Mem. Inst. Field Education, Yokohama National Univ., no. I, p. 9-18,

pI. 1 (in Japanese).
Kojima, S. (1982): Some Jurassic, Triassic and Permian
radiolarians from the eastern part of Takayama
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--(1984): Paleozoic-Mesozoic strata in the Takayama
area, Gifu Prefecture, central Japan: their stratigraphy and structure. Jour. Geol. Soc. Japan, v.
90, p. 175-190, pI. 1 (in Japanese with English
abstract).
Kozur, H. and Mostler, H. (1979): Beitrage zur Erforschung der mesozoischen Radiolarien. Tell III:Die Oberfamilien Actionmmacea Haeckel 1862
emend., Artiscacea Haeckel1882, Multiarcusellacea
nov. der Spumellaria und triassische Nassellaria.
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1-21 (in German with English summary).
- - and-- (1981): Beitrage zur Erforschung der
mesozoischen Radiolarien. Tell IV: Thalassosphaeracea Haeckel, 1862, Hexastyillcea Haeckel,
1882 emend. Petrusevskaja, 1979, Sponguracea
Haeckel, 1862 emend. und weitere triassische
Lithocycliacea, Trematodiscacea, Actinommacea
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Lahm, B. (1984): Spumellarienfaunen (Radiolaria) aus
den mitteltriassischen Buchensteiner-Schichten von
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Li, C. Y., Wang, Q., Liu, X. Y. and Tang, Y. Q. (1982):
Explanatory notes to the tectonic map of Asia,
49p., Cartogr. Pub. House, Beijing.
Li, W. K., Hau, J. X., Zhang, S. X. and Meng, F. Y.
(1979): The main characteristics of the Upper
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--(1983a): Middle and Late Jurassic radiolarian biostratigraphy in the Sakawa and adjacent areas,
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--(1983b): The conformable relationship between
chert beds and clastic beds in the Triassic-Jurassic
sequence of the southern subbelt of the Chichibu

844.

Triassic and Jurassic Radiolaria from China

Belt, Kochi Prefecture. Jour. Geol. Soc. Japan, v.
89, p. 407-410 (in Japanese).
--(1985): Middle Jurassic Keta Formation of thesouthern part of the Middle Chichibu Terrane in
the Sakawa area, Kochi Prefecture, Southwest
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--(1986a): Tricolocapsa yaoi Assemblage (Late
Jurassic radiolarians) from the Togano Group in
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City Univ., v. 29, p. 101-115, pIs. 1-3.
--(1986b): Stratigraphic distribution of two speciesof Tricolocapsa in the Hisuikyo Section of the
Kamiaso area, Mino Terrane. News of Osaka Micro·
paleont., Spec. Vol., no. 7, p. 59-62 (in Japanesewith English abstract).
- - and Yao, A. (1985): Latest Jurassic radiolarians
from the Torinosu Group in Southwest Japan.
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pIs. 1-3.
--and - - (1986): A newly proposed radiolarian
zonation for the Jurassic of Japan. Marine Micro·
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Fossil Museum, no. 8, p. 147-190, pIs. 55-64 (inJapanese with English abstract and description).
--(1986): Continental margin of East Asia in Jurassic
time. Proc. Symp. Geol. Continent. Margins, Nan·jing Univ., Sess. A, p. 7-9.
--(1987): Mesozoic terranes in the Japanese Islands
and neighbouring East Asia. In Leitch, E. C. andScheibner, E. eds., Geodynamic Ser. v. 19, Terraneaccretion and orogenic belts, p. 263-273, Amer.
Geophy. Union, Washington, D. C. and Geol. Soc.
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- - , Hattori, I., Adachi, M., Wakita, K., Okamura, Y.,
Kido, S., Kawaguchi, I. and Kojima, S. (1981):
Jurassic formations in the Mino area, central Japan.
hoc. Japan Acad., v. 57, Ser. B, p. 194-199.
- - and Koike, T. (1982): Radiolarians in the Jurassic
siliceous shale and in the Triassic bedded chert of
Unuma, Kagamigahara City, Gifu Prefecture, central Japan. News of Osaka Micropaleont., Spec. Vol.,
no. 5, p. 117-134, pIs. 1-5 (in Japanese withEnglish abstract).
- - , Kojima, S., Shao, J. A. and Zhang, Q. L. (1986):
Mesozoic radiolarians from the Nadanhada area,
Northeast China. Proc. Japan Acad., v. 62, Ser. B,
p.337-340.
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the Nanto-Nansei area, Mie Prefecture, Kii Peninsula, central Japan. Jour. Earth Sci., Nagoya Univ.,
v. 30, p. 31-107, pIs. 1-10.
- - , Uemura, T. and Yamamoto, H. (1984): Jurassic

273

radiolarians from the Tsugawa area, Niigata Prefecture, Japan. Earth Sci. (Chikyu Kagaku), v. 38,
p. 352-358, pI. I.
Monger, J. W. H. and Irving, E. (1980): Northward dis.
placement of north-central British Columbia.
Nature, v. 285, p. 289-294.
Nagai, H. (1986): Jurassic Eucyrtidiellum (Radiolaria)
from central Japan. Bull. Nagoya Univ. Museum,no. 2, p. 1-21, pIs. 1-2.
Nakaseko K. and Nishimura, A. (1979): Upper Tria,sic
Radiolaria from Southwest Japan. Sci. Rep., Col.
Gen. Educ. Osaka Univ., v. 28, p. 61-109, pIs. 112.
Nishizono, Y. and Murata, M. (1983): Preliminary
studies on the sedimen tary facies and radiolarianbiostra tigraphy of Paleozoic and Mesozoic sediments, exposed along the mid-stream of the Kuma
River, Kyushu, Japan. Kumamoto Jour. Sci., Geol.,v. 12, p. 1-40, pIs. 1-6 (in Japanese with English
abstract).
- - , Ohishi, A., Sato, T. and Murata,M. (1982): Radiolarian fauna from the Paleozoic and Mesozoic
formations, distributed along the mid-stream of
Kuma River, Kyushu, Japan. News of Osaka Micro·
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Owada, K. and Saka, Y. (1982): Preliminary note on the
Paleozoic and the Mesozoic formations in the
Chichibu Belt, Okutama district, KWanto Mountains, Japan. Ibid., no. 5, p. 67-80, pIs. 1-2 (inJapanese with English abstract).
Pessagno, E. A., Jr. (1973): Upper Cretaceous Spurn cllariina from the Great Valley Sequence, California
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In Vallier, T. L. and Brooks, H. C. eds., Geology of
the Blue Mountains region of Oregon, Idaho, andWashington. Geologic implications of Paleozoic
and Mesozoic paleontology and biostratigraphy,
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Geol. Surv. Prof. Paper, 1435, p. 65-78.
- , -and Longoria, J. F. (1984): A revised radiolarian zonation for the Upper Jurassic of western
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- - , Finch, W. and Abbott, P. L. (1979): Upper Triassic Radiolaria from· the San Hip6lito Formation,
Baja California. Micropaleont., v. 25, p. 160-197,
pIs. 1-9.
- - , Longoria, J. F., Macleod, N. and Six, W. M. (1987):

274

Satorn KOJIMA alld Shinjiro MIZUTANIUpper Jurassic (Kimmeridgian-upper Tithonian)
Pantanelliidae from the Taman Formation, eastcentral Mexico: tectonostratigraphic, chronostratigraphic, and phylogenetic implications. Cushman
Found. Spec. Pub., no. 23, p. 1-51, pis. 1-7.
and Whalen, P. A. (1982): Lower and Middle Jurassic Radiolaria (Multicyrtid Nassellariina) from California, east-central Oregon and the Queen Charlotte
Islands, B. C. Micropaleont., v. 28, p. 111-169,
pis. 1-13.
--,-and Yeh, K. Y. (1986): Jurassic Nassellariina(Radiolaria) from North American geologic terranes. Bull. Amer. Paleont., v 91, no. 326, p. 1-75,
pis. 1-11.
Ren, J. S., Jiang, C. F., Zhang, Z. K. and Qin, D. Y.
(1980): The geotectonic evolution of China, under
the direction of Prefessor Huang Jiqing, 124p.,
16pls., Sci. Pub., Beijing (in Chinese).
Riedel, W. R. and Sanfilippo, A. (1974): Radiolaria
from the southern Indian Ocean, DSDP Leg 26.
In Davies, T. A. et al., eds., Initial Reports of the
Deep Sea Drilling Project, v. 26, p. 771-813, pis.
1-15, U.S. Govt. Printing Office, Washington D.C.
Saka, Y. (1983): Preliminary note on the Jurassic strata
in the Chichibu Terrain, western Shima Peninsula,Southwest Japan. Cakujutsu Kenkyu, School of
Educ., Waseda Univ., Ser. Bioi. Ceol., v. 32, p. 2939, pis. 1-6 (in Japanese with English abstract).
Sashida, K., Igo, Hisaharu, Igo, Hisayoshi, Takizawa, S.,
Hisada, K., Shibata, T., Tsukada, K. and Nishimura,
H. (1982): On the Jurassic radiolarian assemblages
in the Kanto district. News of Osaka Micropaleont.,
Spec. Vol., no. 5, p. 51-66, pis. 1-2 (in Japanesewith English abstract).
Sato, T., Murata, M. and Yoshida, H. (1986): Triassic toJurassic radiolarian biostratigraphy in the southernpart of Chichibu terrain of Kyushu, Japan. Ibid.,no. 7, p. 9-23 (in Japanese with English abstract).
Sugano, K., Nakaseko, K. and Wakimoto, R. (1980):
Radiolarians from the Tsuiji group in the easternpart of the Shima Peninsula, Mie Prefecture, Japan.
Mem. Osaka Kyoiku Univ., Ser. III, v. 28, p. 111121, pis. 1-4 (in Japanese with English abstract).
Takashima, K. and Koike, T. (1984): Stratigraphy andgeological structure of the Mesozoic stra ta in the
Gozenyama - Itsukaichi area, southeastern part of
the Kanto Mountains. Sci. Repts. Yokohama Natl.
Univ. Sec. II, no. 31, p. 29-50, pis. 1-3 (inJapanese with English abstract).
Takemura, A. (1986): Classification of Jurassic nassellarians (Radiolaria). Palaeontographica Abt. A,
v. 195, p. 29-74, pis. 1-12.
Tan Sin Hok (1927): Over de samenstelling en het
onstaan van krijten mergelgesteenten van de
Molukken. In Brouwer, H. A. ed., Ceologische
onderzoekingen in den Oostelijken Oost-indischen

Archipel V, Jaarb. Mijnwez. Nederiandsch-Indiii,(1926), p. 5-198, pis. 1-16 (in Dutch).
Tanaka, H., Fujita, H., Miyamoto, T. and Hase, A.
(1985): Discovery of late Jurassic radiolarian fossils
from the Shinkai Formation developed to thesouth of Mt. Haidate, Oita Prefecture, Kyushu.
Jour. Ceol. Soc. Japan, v. 91, p. 569-571, pI. 1(in Japanese).
Ujiie, H. and Hashimoto, Y. (1983): Geology and radiolarian fossils in the inner zone of the Motobu Belt
in Okinawa-jima and its environs. The Earth
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Wakita, K. (1982): Jurassic radiolarians from Kuzuryuko - Gujo-hachiman area. News of Osaka Micropaleont., Spec. Vol., no. 5, p. 153-171, pis. 1-7(in Japanese with English abstract).
- - and Okamura, Y. (1982): Mesozoic sedimentaryrocks containing allochthonous blocks, Gujohachiman, Gifu Prefecture, central Japan. Bull.
Ceol. Surv. Japan, v. 33, p. 161-185, pis. 1-8(in Japanese with English abstract).
Wang, C. Y., Kang, B. X. and Zhang, H. R. (1986): A
discovery of Triassic conodonts in the Nadanhada
Range and geological significance. In CPPTNC
Editorial Committee (Li, C. Y. et al.) eds., Contributions to the project of plate tectonics innorthern China, p. 208-214, pI. 1, Geoi. Pub.
House, Beijing (in Chinese with English abstract).
Yabe, S. (1959): Geologic Map (1:250,000) of PaoCh'ing (NL-53-4) with geologic column and brief
description. Compilation Committee, Ceol. Mineral.
Res. Far East, Tokyo Geogr. Soc., Tokyo.
--and Ohki, K. (1957): Geologic Map (1:250,000) of
T'ung-Chiang (NL-53-1) with geologic column andbrief description. Ibid.
Yamamoto, H. (1983): Occurrence oflate Jurassic radiolarians of the Mirifusus baileyi Assemblage from
Neo Village, Gifu Prefecture, central Japan. Jour.
Ceol. Soc. Japan, v. 89, p. 595-596, pI. 1 (inJapanese).
- - (1985): Geology of the late Paleozoic-Mesozoic
sedimentary complex of the Mino Terrane in thesouthern Neo area, Gifu Prefecture and the Mt.
Ibuki area, Shiga Prefecture, central Japan. Ibid., v.
91, p. 353-369, pIs. 1-2 (in Japanese with English
abstract).
- - , Mizutani, S. and Kagami, H. (1985): Middle
Jurassic radiolarians from Blake Bahama Basin, West
Atlantic Ocean. Bull. Nagoya Univ. Mllseum, no. 1,
p. 25-49, pIs. 1-9.
Yao, A. (1979): Radiolarian fauna from the Mino Beltin the northern part of the Inuyama area, central
Japan. Part II: Nassellaria 1. Jour. Ceosci., Osaka
City Univ., v. 22, p. 21-72, pIs. 1-12.
- - (1982): Middle Triassic to Early Jurassic radiolarians from the Inuyama area, central Japan. Ibid.,

844. Triassic and Jurassic Radiolaria from China
v. 25, p. 53-70, pIs. 1-4.
--(1983): Late Paleozoic and Mesozoic radiolarians
from Southwest Japan. In Iijima, A., Hein, J. R.
and Siever, R. eds., Siliceous Deposits in the PacificRegion, p. 361-376, Elsevier, Amsterdam.
- - (1984): Subdivision of the Mesozoic complex in
Kii-Yura area, Southwest Japan and its bearing on
the Mesozoic basin development in the Southern
Chichibu Terrane. Jour. Geosci., Osaka City Univ.,
v. 27, p. 41-103, pis. 1-5.
- - , Matsuoka, A. and Nakatani, T. (1982): Triassic
and Jurassic radiolarian assemblages in Southwest
Japan. News of Osaka Micropaleont., Spec. Vol.,
no. 5, p. 27-43, pIs. 1-4 (in Japanese with

275

English abstract).
Yokota, S. and Sano, H. (1986): Radiolarian fossils from
the Middle Jurassic Ammonites-bearing formationof Bisho, Yatsushiro district, Kumamoto Prefecture. Ibid., no. 7, p. 53-58, pI. 1 (in Japahese withEnglish abstract).
Yoshida, H. (1986): Upper Triassic to Lower Jurassic
radiolarian biostratigraphy in Kagamigahara City,
Gifu Prefecture, central Japan. Jour. Earth Sci.,
Nagoya Univ., v. 34, p. 1-21, pis. 1-17.
Zhang, Zh. M., Liou, J. G. and Coleman, R. G. (1984):
An outline of the plate tectonics of China. Geol.
Soc. Amer. Bull., v. 95, p. 295-312.

Nadanhada* Jj~ftli(3-~, Mino ~i/l1t, Sino-Korean paraplatform "1"~Jll!L!j!:!*!1f!, Inner Mongolia* P:I~

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ml, Tamba ftilll, Ashio JE~, Khanka* ~~}L Jiamusi* ft* Wi, Erlianqiao*
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Chinese name),*,OO}1Ut.tt!!:n, JJ~ft*~.tt!!~.l: I)':::~~C, :/;L 7*cljjd~!t\lt15(7)P1I±l: ,*,OO*~t$J.j~ft*~.tt!!
r .l: I) .:::~*c1iJ(I!t!t\lt15, "* t.:J1JiJi!6-.l: I) :/ ;L 7 *c1iJ(l!t!t\ It15 (7)P11±l z-~cJlllt Lt.:-t h I? 11, Capnodoce traversi, Eucyrtidiellum ptyctum, E. unumaense, Guexella~(7)~:!*?,- -l> 0nudata, Livarella validus, Parahsuum (?) sp. A, Pentactinocarpus sp. A, Poulpus
curvispinus, Pseudostylosphaera japonica, P. d. hellenica, P. d. tenue, P. sp. A. P. sp. B.
P. sp. C. P. sp. D, P. sp. E. Stichocapsa convexa. Triassocampe deweveri, T. sp. A,
Tricolocapsa(?) fusiformis, T. plicarum. T. tetragona, T. d. ruesti, Yeharaia annulata, Y.
japonica. Y. sp. A. ""(·~~o fm:!*?'- -l> - r .!: J1JiJi!6-(7) Iliff\;; 11 , -th.f:h, .:::~*c,*,Wl:}';.l: 0'1&
JtIj (late Anisian iJ' I? Ladinian:}.; .l: 0' late Carnian iJ'G Norian), :/;L 7 *c <~I Wl (Bathonian iJ'
I? Callovian) ""(·~~o'H~ :W. IMH$i'fli'.![lTrans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 276-284,4 Figs., December 30,1987

845. ATTENUATELLA (BRACHIOPODA) FROM THE UPPER PERMIAN

OF NORTHEAST JAPAN AND ITS BIPOLAR DISTRIBUTION*
JUN·ICHI TAZAWA
Department of Earth Sciences, Faculty of General Education, Niigata University, Niigata 950·21

Abstract. Attenuatella bandoi, sp. nov. is described from the Upper Permian (Djulfianbeds) of the lower Toyoma Formation of Ishihama, Utatsu district, southern Kitakami Mountains, northeast Japan. The genus Attenuatella is distributed in Middle Carboniferous (Moscovian) to Upper Permian (Dorashamian) strata of Spitzbergen, Soviet Arctic, Siberia, Urals,
northern Yukon, west Texas, northern Mexico, eastern Australia, New Zealand, New Caledonia,
northern Thailand, northern China and northeast Japan, mostly in the Lower and Middle
Permian of the Boreal and Gondwana Provinces.

other genera to Attenuatella (see Armstrong,
1968, p. 786).
The present paper indicates the first occurrence of Attenuatella in Japan. The specimens
described here as Attenuatella bandoi, sp. nov.
were collected by myself and Dr. M. Ehiro from

Introduction
Attenuatella is a small, very distinctive spiriferid belonging to the family Ambocoeliidae
George, 1931. This genus was established by
Stehli in 1954, with Attenuatella texana Stehli,
1954 from the Bone Spring Formation of the
Sierra Diablo Mountains, west Texas as typespecies. At that time Stehli assigned Crnrithyris
attenuata Cloud, 1944 from the Middle Permianof Coahuila, northern Mexico to the new genus.
Since then it has been described from Middle
Carboniferous to Upper Permian strata of Russia(Ustritsky and Tschernjak, 1963; Zavodowsky,
1968; Zavodowsky and Stepanov, 1970;
Solomina, 1978; Kalashnikov, 1980; Kalashnikov
and Ustritsky, 1981; Abramov and Grigorjeva,
1983), North America (Bamber and Waterhouse,
1971; Cooper and Grant, 1976), Australia(Waterhouse, 1967; Armstrong, 1968; Armstrong
and Brown, 1968; Armstrong and Telford,
1970; Waterhouse et at., 1983), New Zealand(Waterhouse, 1964, 1968; Landis and Waterhouse, 1966), New Caledonia (Landis and Waterhouse, 1966), Thailand (Waterhouse, 1983) andChina (Lee et at., 1980, 1982). In addition, someRussian species have been transferred from[t~·..'??f

':~.;

t

141!'14'E

!

:0;11

I~. ': ~C '"\\:~,,,·,,;·.$;1~1~O:.'t~~~'I';;

I,.:,.,,' .. s!

~.(";/. 9'::..

0lkm

Figure l. Map showing the fossil locality (using
the topographical map of "Tsuya" scale 1 :50,000 published by Geographical Survey Institute of Japan).

*Rcceived September 14, 1987.
276

845. Attenuatella [rom Japan
shale or calcareous shale in the lower part of thelower Toyoma Formation (lower conglomeratic
beds of the Suenosaki Formaiton of Ehiro andBando, 1985) in the eastern coast of Ishihama
Utatsu district, southern Kitakami Mountains'
northeast Japan (Figure 1). Age of the fossilifer~o~s s~ales of Ishihama is estimated to be early
DJulflan on the basis of some ammonoids
Araxoceras and Prototoceras (Ehiro and Bando'
1985~,
The Upper Permian Toyoma Formation ischaracterized by its fauna bearing several Tethyanelements, such as Colaniella, Palaeo[usulina,
Tschernyshewia, Oldham ina and Araxoceras, andassociated with only a few Boreal elements
Megousia (Murata and Bando, 1975; Tazawa:
1975, 1982; Ishii et al., 1975; Ehiro and Bando
1985). A ttenuatella is considered to be a coo!
or cold-water element, judging from the bipolar
distribution, i.e., the Boreal and Gondwana
Provinces (Figure 2, Table 1). The nature of the
Toyoma fauna suggests that the sea covering thesouthern Kitakami region in late Permian time
occupied the boundary area between the Boreal

277

and Tethyan Provinces.

Distribution of Attenuatella
The genus Attenuatella is distributed in the
Middle Carboniferous (Moscovian) to the Upper
Permian (Dorashamian) of Spitzbergen, Soviet
Arctic (Novaya Zemlya, Taimyr), Siberia (Verkhoyansk, Kolyma-Omolon), Urals, northern
Yukon, west Texas, northern Mexico, eastern
Australia, New Zealand, New Caledonia, northern Thailand, north and northeast China (NeiMongol, Jilin, Heilongjiang) and northeast Japan(Figure 2). The following 23 species are knownat present, and most of them occur in the Lower
and Middle Permian of the Boreal and Gondwana
Regions (Table 1):
Attenuatella acutirostrus (Krotov, 1885),
from the Lower Permian (Artinskian beds) of
the Ural Mountains, U.S.S.R. (Krotov, 1885).
A ttenuatella stringocephaloides (Tschernyschew and Licharew, 1939), from the Lower
Permian (Spirifer Limestone and Brachiopod
Chert) of Spitzbergen; Lower Permian (Sokolovskaya Formation) of Novaya Zemlya, U.S.S.R.;~~----------------------~~~~~~----80°

oo------t-~~~------~~~~--------------------+---~=--Oo

40o------------------------------~~~JL------------------~~~----40°
New ZealandFigure 2. Geographical 'distribution of Attenuatella (modified from Armstrong, 1968 to incorporate
the data of Siberia, norther.n Cana<!a and East Asia).

lun-ichi TAZA WA

278

Lower to Middle Permian (Birrangsky Horizon)of Taimyr (Tschernyschew and Licharew in
Licharew and Einor, 1939; Ustritsky andTschernjak, 1963; Kalashnikov and Ustritsky,
1981 ).
A ttenuatella attenuata (Cloud, 1944), from
the Middle Permian (Waagenoceras Zone or
Polydiexodina Zone) of Coahuila, northern
Mexico (Cloud, 1944; Cooper and Grant, 1976).
Attenuatella texana Stehli, 1954, from theLower Permian (Bone Spring Formation) of the
Sierra Diablo Mountains, west Texas, U.S.A.
(Stehli, 1954; Cooper and Grant, 1976).
A ttenuatella taimyrica Tschernjak, 1963,
from the Middle Permian (Baikursky Horizon)of Taimyr, U.S.S.R. (Ustritsky and Tschernjak,
1963).

Attenuatella incurvata Waterhouse, 1964,
from the Middle Permian (Arthurton andKuriwao Groups) of New Zealand; Middle Permian (Chhidruan beds) of New Caledonia; Middle
Permian of Heilongjiang, northeast China (Waterhouse, 1964; Landis and Waterhouse, 1966; Leeet al., 1980).
Attenuatella sp. cf. A. incurvata Waterhouse,
1964, from the Middle Permian (Barfield Formation) of Queensland, eastern Australia (Armstrong, 1968).
A ttenuatella mUltispinosa Waterhouse, 1967,
from the Middle Permian (Gilgurry Mudstone)of New South Wales, eastern Australia (Waterhouse, 1967; Armstrong and Telford, 1970).
Attenuatella australis Armstrong and Brown,
1968, from the Lower Permian (Gigoomgan

Table 1. Stratigraphical and geographical distributions of Attenuatella.

Species

Carbon.
M

U

PermianL++

II. acutirostrus
II. stringocephaloides

II. attenuata

M

U.S.S.R. (Ural Mts.)+

U.S.S.R. (Novaya Zemlya, Taimyr), Spitzbergen+

Mexico (Coahuila)+

II. texana

Reg i o nU

U.S.A. (Texas)

II. taimyrica+

II. incurvata+

New Zealand, New Caledonia, China (Heilongjiang)

II. cf. illcurvata+

Australia (Queensland)+

Australia (New South Wales)

II. multispinosa

U.S.S.R. (Taimyr)

A. australis+

Australia (Queensland)

II. cf. australis+

Australia (New South Wales)

A. convexa+

Australia (Queensland, New South Wales)

II. sp. A (Armstrong, 1968)+

Australia (Queensland)

A. sp. (Armstrong, 1968)+

Australia (Queensland)

A. altilis
A. omolonellsis+

A. cf. omolonensis++

New Zealand+

U.S.S.R. (Verkhoyansk Mts., Kolyma-Omolon Mts.)+

A. dorogoyiA.

sp. (Bamber& Waterhouse, 1971)

II. uralica

Canada (Yukon Territory)+

U.S.S.R. (Omolon River Basin)+

Canada (Yukon Territory)+

U.S.S.R. (Ural Mts.)

A. paraincurvata+

A. xiujumqinqiensis+

China (Jilin, Nei Mongol)
China (Nei Mongol)

II. pi yas.ini+

Thailand (Chiangmai)

II. bandoi+

Japan (Kitakami Mts.)279

845. Attenuatella from Japan
Limestone) of Queensland, eastern Australia(Armstrong and Brown, 1968).
A ttenuatella sp. cf. A. australis Armstrong
and Brown, 1968, from the Lower Permian(Farley Formation) of New South Wales, eastern
Australia (Armstrong and Telford, 1970).
Attenuatella convexa Armstrong, 1968, fromthe Lower Permian (Tiverton FOrIIIation) of
Queensland, eastern Australia; Lower Permian(Farley Formation) of New South Wales, eastern
Australia (Armstrong, 1968; Armstrong andTelford, 1970; Waterhouse et al., 1983).
Attenuatella sp. A, from the Middle Permianof Queensland, eastern Australia (Armstrong,1968).
Attenuatella sp., from the Middle Permian(Flat Top Formation) of Queensland, eastern
Australia (Armstrong, 1968).
A ttenuatella altitis Waterhouse, 1968, fromthe Lower Permian (Wesney Siltstone andTakitimu Group) of New Zealand (Landis andWaterhouse, 1966; Waterhouse; 1968).
A ttenuatella omolonensis Zavodowsky, 1968,
from the Middle and Upper Carboniferous(Siederskaya and Khaldanskaya Formations) of
the nort4ern Verkhoyansk Mountains, U.S.S.R.;
Upper Carboniferous to Lower Permian of theKolyma-Omolon Massif, U.S.S.R. (Zavodowsky,
1968; Zavodowsky and Stepanov, 1970; Solomina, 1978; Abramov and Grigorjeva, 1983).
A ttenuatella sp. cf. A. omolonensis Zavodowsky, 1968, from the Lower Permian (A ttenuatella-Tomiopsis Zone) of northern Yukon
Territory, Canada (Bamber and Waterhouse,1971).
Attenuatella dorogoyi Zavodowsky, 1970,
from the Middle Permian (Omolon Horizon) of
the Omolon River Basin, U.S.S.R. (Zavodowsky
and Stepanov, 1970).
Attenuatella sp., from the Lower Permian(Attenuatella Zone) of northern Yukon Territory,
Canada (Bamber and Waterhouse, 1971).
Attenuatella uralica Kalashnikov, 1980, from
the Middle Carboniferous (Moscovian beds) of
the Ural Mountains, U.S.S.R. (Kalashnikov,

1980).
A ttenuatella paraincurvata Lee and Su, 1980,

from the Middle Permian (Wujiatun Formation)of Jilin, northeast China; Middle Permian of Nei
Mongol, north China (Lee et al., 1980).
Attenuatella xiujumqinqiensis Lee, Gu and Li,
1982, from the Middle Permian (Jisu Formation)of Nei Mongol, north China (Lee et al., 1982).
Attenuatella piyasini Waterhouse, 1983, fromthe Upper Permian (Huai Tak Formation) of
Chiangmai, northern Thailand (Waterhouse,1983).
Attenuatella bandoi Tazawa, sp. nov., fromthe Upper Permian (lower Toyoma Formation)of the southern Kitakami Mountains, northeast
Japan.
Systematic descriptions
Order Spiriferida Waagen, 1883
Suborder Delthyrididina Ivanova, 1972
Superfamily Martiniacea Waagen, 1883
Family Ambocoeliidae George, 1931
Genus Attenuatella Stehli, 1954
Attenuatella Stehli, 1954, p. 343; Waterhouse, 1964,
p. 108; Armstrong, 1968, p. 786, Cooper and Grant,
1976, p. 213l.
non Attenuatella Winkler Prins, 1970, p. 538; lin etai., 1979, p. 120.

Type species:-Attenuatella texana Stehli,
1954, p. 343, pI. 25, figs. 31-33.
Diagnosis:-Small to medium, nearly planoconvex and narrowly elongate Ambocoeliidae.
Ventral umbo greatly attenuated and strongly
incurved. External surface of both valves ornamented by numerous, very fine spine bases.
Pedicle valve interior with a long median ridge,
on which adductors and diductors attached.
Brachial valve having a large, tuberculate cardinal
process and massive crura; spiralia absent.
Remarks: -The description of the type species
by Stehli was based on a single pedicle valve
specimen, so that the external and internal features of the brachial valve have long been unknown until the redescription by Cooper and
Grant (1976, p. 2132). The dorsal internal
structures of Attenuatella species were describedJun-ichi TAZA WA

280

8b

845. Attenuatella from Japanin detail by Waterhouse (1964) and Armstrong(1968), using materials of New Zealand andAustralia. The pecurior, loop-like brachialskeleton was reconstructed and illustrated by
Armstrong (1968, text-fig. 2).
Armstrong (1968, p. 786-788, text-fig. 3)
summarized the stratigraphical and geographicaldistributions of Attenuatella, and gave the rangeof the genus as lower Artinskian (Aktastinian)to Kazanian or Wordian. But afterwards, its
Middle Carboniferous and Upper Permian occurrences were disclosed: A. uralica from the
Moscovian beds of the Urals (Kalashnikov,
1980), and A. piyasini from the lower Dorashamian beds of northern Thailand (Waterhouse,1983).
Both of the species, A. aff. frechi (Schellwien)
from the Upper Carboniferous of northeast
Spain (Winkler Prins, 1970) and A. bisulcata(Ustritsky) from the Lower Permian of northeast
China (Jin et al., 1979) cannot be assigned toAttenuatella because of their massive ventral
umbo.

Attenuatella bandoi, sp. nov.
Figures 3-1-11, 4Material: - Forty-six specimens, from thelower part of the lower Toyoma Formation in
the eastern coast of Ishihama, Utatsu-cho, Motoyoshi-gun, Miyagi Prefecture, northeastern Honshu: (1) two conjoined valves, NU-B 1 (holotype,Figures 3-9a-c), 2; (2) one pedicle valve, NU-B
3; (3) external and internal moulds of eightpedicle valves, NU-B 4-11; (4) external moulds
of five pedicle valves, NU-B 11-16; (5) internalmould of a pedicle valve with some shell remains,
NV-B 17; (6) internal moulds of twenty-seven+- Figure 3.

281

pedicle valves, NU-B 18-44; (7) external mouldof a brachial valve, NV-B 45; (8) internal mouldof a brachial valve, NU-B 46.
All the specimens are stored in the Department of Earth Sciences, Faculty of General
Education, Niigata University.
Diagnosis:-Large, elongate Attenuatella, lacking ventral sulcus and dorsal fold. Micro-ornament of numerous spine bases which occurringwith a density of 8-9 per mm on pedicle valve,9-10 per mm on brachial valve.
Description:-Shell of large size for genus,
elongate oval in outline and plano-convex inprofile; greatest width at slightly anterior tomidvalve; length of pedicle valve 16 mm, widthof pedicle valve 12 mm, hinge width 11 mm,
length of brachial valve 10 mm, height of shell 8mm in the holotype.
Pedicle valve strongly inflated, with a narrowand incurved umbo; lateral slopes steep; sulcus
absent. Delthyrium open and high; width of bottom 2.7 mm, height 3.8 mm in the holotype.
External surface of pedicle valve ornamented bynumerous, very fine spine bases, which occurringwith a density of 8-9 per mm at about midvalve(Figure 4). Brachial valve semicircular in outline
and almost flat, but slightly swollen in umbonal
region. Surface ornament consisting of concentric, fine growth lines and numerous spine bases;
the latter occurring with a density of 9-10 per
mm at about midvalve.
Internally, pedicle valve having a long medianridge, on which muscle scars sited. Median ridge
extending over posterior three-quarters of shelllength, separated by a narrow median groove
through its length and tapering towards anterior
portion; maximum width 1.2 mm in an averagesized specimen (NV-B 10, Figures 3a, b). Teeth

Attenuatella balldoi Tazawa, sp. nov., from the lower part of the lower Toyoma Formation of
Ishihama, southern Kitakami Mountains, northeast Japan. (All figures are x4). la, b: ventral and lateral views of
pedicle valve, NU-B 3; 2: ventral view of internal mould of pedicle valve, NU-B 20; 3a, b: ventral and lateralvicws of internal mould of pcdicle valve, NU-B 10; 4: ventral view of internal mould of pedicle valve, NU-B 19;
Sa, b: ventral and lateral views of internal mould of pedicle valve, NU-B 31; 6a, b: ventral and lateral views ofinternal mould of pedicle valve, NU-B 6; 7: ventral view of internal mould of pedicle valve, NU-B 32; 8a, b:
ventral and lateral views of internal mould of pedicle valvc, NU-B 39; 9a, b, c: ventral, dorsal and lateral vicws
of <;onjoincd valve, NU-B 1 (holotypc); 10: dorsal view of external mould of brachial valve, NU-B 45; 11: dorsal
vicw of intcrnal mpuld of brachial valve, NU-B 46.

Jun-ichi TAZAWA

282

not observed. Brachial valve having a large, tuberculate cardinal process and a pair of prominent ,wide sockets which bounded by robust inner
socket ridges. Crural bases fused with inner
socket ridges; the former being sessile and strongly developed. Both of brachidia and muscle scars
not observed.
Remarks :-Attenuatella bandoi, sp. nov. may
be the largest one among known species of thegenus. This species is named in honour of the late
Dr. Yuji Bando, who contributed to the knowledges on Permian and Triassic ammonoids ofJapan, and who first described some Upper Permian ammonoids from the present locality of
Ishillama. In size and outline, the Kitakami
species is close to A . incurvata Waterhouse,originally described from the Middle Permian(Kazanian beds) of New Zealand. But this new
species is distinguished from incurvata by its
slightly larger and more elongate shell and moresparse spine bases (10- 14 per nun in A. incurvata, after Waterhouse, 1967 , p. 171).
A. altiUs Waterhouse from the Lower Permian(upper Sakmarian to lower Artinskian beds) of
New Zealand differs from the present species in
its smaller shell, and in having a low fold andcostae on brachial valve .
An Upper Permian form , A. piyasini Waterhouse from the Huai Tak Formation of northern
Thailand is readily distinguished from the present
species by its much smaller and less elongate

Figure 4.

shell.
The type species, A. texana Stehli is characterized by its small size and elongate outline, andis clearly distinguished from the Kitakami
species.
Acknowledgments
I thank Dr. M. Ehiro, Department of Earth
Science, College of General Education, Tohoku
University , for providing specimens he collected
and information on stratigraphic data of thefossil locality ; Prof. Y. Hasegawa, Dr. 1. Niikawa
and Dr. A. Matsuoka , Department of Earth
Sciences, Faculty of General Education, Niigata
University, for critical reading of the manuscript.
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vol. 10, no. 3, p. 111-153, pis. 1-6.
- - , Briggs, D. J. C. and Parfrey, S. M. (1983): Major
faunal assemblages in the Early Permian Tiverton
Formation ncar Homevale homestead, northern
Bowen Basin, Queensland. In: Permian Geologyof Queenslalld, p. 121-13 8, pis. 1-3, Geo!. Soc.
Aust., Qd. div.
Winkler Prins, C. F. (l970): Brachiopod descriptions.
III Wagner, R. H. and Winkler Prins, C. F.: The
stratigraphic succession, flora and fauna of Cantabrian and Stephanian A rocks at Barruelo (prov.
Palencia), N. W. Spain. Congr. Colloq. Univ. Lit~ge,

vol. 55, p. 531-542, pis. 36-38.
Zavodowsky, V. M. (1968): 3aBo.lloBckHil, B. M:.
HOBbie BII.llbl nepMCKUX .lleJlTllpllal\Hil CeBepoBOCTOKa CCCP : HOBbie BIl.llbl .llpeBHHX paCTeHuil
U ueCn03BO'lHbIX CCCP, Bblll. 2, p. 169-173,
He.llpa, MocKBa.
--- and Stepanov, D. L. (1970): 3aBO.llOBCkuil,
B. M., CTenaHoB, n. JI. : opaXUOnO.llbI.
In
3aBO.llOBCKUil, B.M., CTenaHoB,n. JI., OaJlalllOBa,
E. A., EJlTblllleBa, P. C., JIo6aHoBa, O. B.,
JIIOTKeBU'l, E. M., MUK.nyxc-MaKJlail, A. n.,
HexopoIlleB, B. n., nOnOB, 10. H., Pa.ll'leHKO,
r. n., COKOJlOB, D. C. : nOJleBoil aTJlaC nepMcKoil<j>aYHbl U <j>JlOPbl CeBepo-BocToKa CCCP, p. 70182, pis. 3-96, Mara.llaH. KH. H3.ll-BO, Mara.llaH.

Ishihama E~, Motoyoshi-gun *ilftt~, Suenosaki ;j(0)d$J, Toyoma ~*, Utatsu-cho illXl$lBJ.

:5R~t S *O)J::$~/V A*it~,@~ Attenuatella:to J: <:f~!1ii.O)jilijtj.'I1:7t;(P : m$~tJ::J.lJ!t!!, -g~.*ilfaillXl$IBJE~:5R~.*K~lli~~J::$~~A*(X~77-~~$~*~~$0).~tE1}('l!{.~il' I?, ~b;OO,,('lt:m1rb-C O)~,@~ Attenuatella b;l*1t ~.h t.:. ;:.h ~ Attenuatella
bandoi t~;g L, ~tlt~~. Attenuatella It7- l::"", '/ ..-{Iv 7" /' • :; llfB~tti!t!!~ . ""..-{ !I 7 . ry
7IVJ.lJ~ • ::L - ::I /'~t$ . T 4'--If'7-l1§$ . .I- 4'- "" ::I ~t$ . :;t - 7- " 7 !I 7:5R$ • =- =>, -:/ - 7 /',,'. =-=>,-7J v \-'=-7' j11~t$' 9='OO~t$:toJ:<:f:5R~tS*O)9='$EER* (,,£;7-::I-I;~n tJ'l?J::$~~A*(\-'7"".A~)K7t;(P~~~,~K~v7~!t!!.t~/'\-'?~!t!!.0)~$-9='$~

IVA*t.:.1t9=' L -C~'~.

EHiR.~-

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 285-305,16 Figs., December 30,1987

846. TAPHONOMY OF AMMONITES FROM THE CRETACEOUSYEZO GROUP IN THE TAPPU AREA, NORTHWESTERN HOKKAIDO, JAPAN*
HARUYOSHI MAEDA
Departmcnt ur Gculugy, Kochi University, Kochi 780

Abstract. Taphonomy of ammonites in the Cretaceous Yezo Group has been discussed on
the basis of field and laboratory observations of many specimens from the Tappu area, northwestern Hokkaido. The Cretaceous deposits in the study area arc represented mainly by monotonous, off-shore muddy sequence attaining several thousand meters thick, and yield numerous
ammonites and other molluscan fossils at varioius horizons. Ammonite fossils are preserved inboth calcareous concretions and surrounding mudstone. Most specimens from a well-laminatedmudstone of the lower stratigraphic levels [lower to middle Cenomanian] are large-sized, andhave been suffered compaction and dissolution, even they are preserved in calcareous concretions. On the contrary, ammonites including immatures, are quite well preserved in sphericalor mushroom-shaped calcareous concretions, embedded in intensely bioturbated mudstone of
the upper stratigraphic levels [middle Turonian to upper Santonian]. Such concretions might
have consolidated in earlier stage than those of the lower stratigraphic levels before ammonite
shells suffered diagenetic damage. Intermediate preservational features are observable in theuppermost Cenomanian to the lower Turonian.
Large ammonites, occurring solitarily in mudstone are generally much poorly preserved
than the moderate-sized ones. Several interesting mode of preservation: for example, "halfammonite" and "ventral-tire", are observable at various horizons in the area surveyed. Becauseof preservational uniformity of "half-ammonites" belonging various taxa and occurring fromvarious horizons, the mode of preservation may be originated from partial sedimentary fillingin phragmocone, prescribed by position of septal neck, and diagenetic compaction and shelldissolution after complete burial.
Ammonite shells and plant remains were drifted similarly and accumulated at the sameplaces as patches on the sea floor. In some cases, they are concentrated in lower umbilical voidof horizontally laid large ammonite shell. Large ammonite shells might probably trigger off
such accumulations, acting as a "trap" on the sea floor. Some spatangoids, preserved regularlyin the umbilical void of large ammonite, might assemble to eat organic matter accumulat,ed
there.

Yezo Group and contemporaneous deposits in·
Sakhalin yield numerous well-preserved ammonites at various horizons. These ammonite fossils
have been studied from the various points ofview since last century (e.g., Yokoyama, 1890,
limbo, 1892; see Matsumoto, 1975). Ammonite
and inoceramid biostratigraphy of the group has
already been well established (Matsumoto, 1942,
1943, 1959, 1977 etc.), and more than two hundred ammonite species have hitherto describedfrom the Yezo Group during this century. In
addition to the biostratigraphic and taxonomic

Introduction
Post-Aptian marine Cretaceous deposits arewidely distributed in the central zone of Hokkaido and Sakhalin (Figure I). Those in Hokkaido
have long been lithostratigraphically subdivided
into the Lower, Middle, Upper Yezo Groupsand Hakobuchi Group in upward sequence, butthey are now summarized as the Yezo Group or
Yezo Supergroup (Okada, 1979, 1983). The*Receivcd September 9, 1987.

285

286

Haruyoshi MAEDA

approach, paleoecological studies of ammonites
were made recently (e.g., Tanabe, 1979; Tanabe
and Ohtsuka, 1985).
In contrast to these works, little has been
done for the detailed analysis on the mode ofammonite occurrence and preservation. Extinct
animals without any allied recent animals such as
ammonites should be at first investigated on theirmode of occurrence. It may involve many informations on their mode of life and depositional
environments.
During the course of paleontological studies
of Cretaceous ammonites from Hokkaido, I haverecognized interesting mode of occurrence andpreservation in many specimens from the selected areas. In this paper, I describe the mode ofoccurrence and preservation of several ammonite

Figure l. Distribution of the Cretaceous deposits
in the meridional zone of Hokkaido and Sakhalin.
AB: Abcshinai; BI: Bibai; IK: Ikllshllmbetsll; OY:
OYlIbari (modified frum Matsumoto, 1954 J.

specimens from the Cretaceous deposits in Hokkaido and Sakhalin as the basis for further research on the ammonite taphonomy and paleoecology. 1 also discuss the probable taphonomic
history of ammonites from the Yezo Group on
the basis of the observed results. The material
utilized is UMUT. (University Museum, University of Tokyo) and KSG. (Geological Deparment, Kochi University) specimens collected bymyself and other paleontologists since lastcentury.
Geological setting
The Cretaceous System in the meridionalzone of Hokkaido and Sakhalin (Figure 1) is athick clastic sequence attaining several thousand
meters thick. Off-shore facies characterized bythick, monotonous, dark-colored mudstone predominates in central region of the Cretaceous
outcropping zone; e.g. Abeshinai, Tappu andOyubari areas (Figure 1). Similar mudstone facies
extends laterally, particularly in N-S direction.
The sediments tend to coarse in grain and thinner
toward the western marginal area (e.g., Ikushumbetsu and Bibai areas; Figure 1).
In this paper, the Cretaceous succession in
the Tappu (=Obira) area where the more or lessoff-shore mudstone facies is well-developed, isdiscussed (Figure 1). Figure 2 shows a generalized columnar section of the Cretaceous in thearea. It attains more than 6000 m thick, andlithostratigraphically divided into the Middle
and Upper Yezo Groups which correspond to
the lower Cenomanian to upper Santonian. Bothgroups consist mainly of thick, dark-coloredmudstone, except in the lowest part of the
Middle Yezo. Such mudstone intercalates turbiditic sandstone beds, slump deposits, and acidic
tuff beds at several stratigraphic levels.
Although monotonous mudstone predominates throughout the Yezo Group, detailed sedimentary features of the mudstone are fairly
variable at different horizons (Maeda, in preparation). Roughly speaking, the following four mudstone units can be recognized in upward sequence (Figure 2).

846.

LI T H OLOG Y

Taphonomy of ammonites from Hokkaido
HORIZON (LOC. NO.)

TUFF

287

MUDSTONE TYPEz«
Intenselyz0

bioturbated

(4)

tZ

... SA3.409 , 410«

mudstone. . ... SA2.. . ... _123 . .

.080

1Il
~

Lami na ted ms.

Z
0

a..

u

z
«
z

I---I~~~~.~.. · · · .504·

Ua
::J

· C01

·505
_004

···· ···· ···· · ··

· TU3

.000
_002

0

0
0::

0::

::J
t-

D

~~~ . .. . · · ·.045 ·(3)········· · TU1.049,527. .. • 050 . .
.606···CE5.

Weakly bioturb. ms.
b. ms .

~~~~~~
~~ W.
• 607

z

·CE4

«
z

-------·618

Well-laminatedN-620.. . .. _621

0z

W. b. ms.

0

«
L

( 2)

W. b. ms.

W

. . . . . .. .. . . . . .. . . ..... . .... CE2(1)

mudstone

_622
-623

W
_624

u

>-

Planolites ms .

Figure 2.
Generaliz ed columnar section of th e Cretaceou s System in the Tappu area. Exact locations
should be mad e reference to Maeda (in preparation).

288

Hantyoshi MAEDA(1) Well-laminated mudstone unit [lower Cenomanian] .
(2) Well-laminated mudstone unit with intercalations of weakly-bioturbated mudstone[middle to upper Cenomanian] .
(3) Planolites mudstone unit [uppermost Cenomanian to lower Turonian] .
(4) Intensely bioturbated mudstone unit [middle Turonian to upper Santonian] .
The upper part of the Yezo Group is generally
much intensely bioturbated than the lower part.
The same evidence is also confirmed in otherareas of Hokkaido (e.g. Bibai area: Maeda, 1986;
Figure 1). Muddy deposits contain calcareous
concretions of various size and shape. Numerous
ammonites occur from both calcareous concretions and surrounding mudstone.
Mode of ammonite occurrence andpreservation in calcareous concretion
Ammonite fossils from the Cretaceous Yezo
Group in Hokkaido are mostly found in calcareous concretions embedded in muddy deposits.
In the Tappu area, their detailed mode of occurrence is, however, fairly variable at different
stratigraphic horizons. Detailed observations forthe moderate-sized ammonites (ca. 2 to 15 cm indiameter) in calcareous concretions are summarized as below.
Occurrence in the Cenomanian: Dark-gray(N3) to medium gray (N4), well-laminated mudstone predominates in the Cenomanian (Mb to
the middle part of Mf-h in Figure 2). Desmoceras(Pseudouhligella) japonicum, Anagaudrycerassacya and Calycoceras orientale are dominant
in the sequence. They are found individually inflat, lenticular-shaped calcareous concretions
ranging from 5 to 30 cm in diameter, where sizeand shape are strongly controlled by the ammonites contained. Most specimens contained in
the calcareous concretions are mature or in
middle-growth stage, and lay horizontally. Small
immature shells, less than 1 cm in diameter, arescarcely found. Figure 3 shows a typical example
of such preservation of ammonite in a lenticularcalcareous concretion embedded in well-lam i-nated mudstone at Loc. TP-613 (Mf-h member;
middle Cenomanian; see also Figure 2). The shellof Anagaudryceras sacya is only preserved its
lower half, and the upper flank and the inner
whorls have been dissolved away (Figure 3A).
Figure 3B shows another example of the similarammonite preservation in a calcareous concretion. In the case, the fully septate phragmoconeof Desmoceras (Pseudouhligella) japonicum ispreserved in its original shell-geometry, but its
inner whorl, siphuncle and original shell materials
have been dissolved away. As described above,
ammonites in well"laminated mudstone of thelower stratigraphic levels are generally poorly
preserved. Many of them are collapsed or havesuffered shell dissolution during diagenetic
process, even in case found in the calcareous
concretions. Plant remains are usually few inthe ammonite-bearing calcareous nodules, although large drifted wood particles are occasionally seen. Ammonites are rare in the surrounding
mudstone.
It is noticeable that the mode of preservationof ammonite within the calcareous nodules isvariable within the Cenomanian mudstone sequence. Figure 4 is a diagramatic sketch showing
the mode of preservation in weakly bioturbatedmudstone at Loc. TP-617 (Mf-h member; middle
Cenomanian; Figure 2). In this case, both living
chamber and septate phragmocone of an adultshell of Desmoceras (PseudouhUgella) japonicum
has been collapsed horizontally during diagenesis,but, shell wall and septa have still remained
except for the inner whorls. In general, ammonite specimens found in calcareous concretions
embedded in weakly bioturbated mudstone
occur more abundantly and more well preserved
than those in well-laminated mudstone.
Occurrence in the uppermost Cenomanian tothe lower Turonian: The uppermost part of themember Mf-h and the member Mj-k [uppermost
Cenomanian to lower Turonian] exhibit intermediate features between the lower members andupper members for the mode of fossil preserva·
tion. Mudstone in these strata is occasionallymoderately or weakly bioturbated, and in suchhorizons abundant Planolites burrows are ob-846.

Taphonomy of ammonites from Hokkaido

289

shell dissolved-

shell preserved

fully septate phragmocone( filled with mud )Figure 3.
Mode s of amm o nite occurrence a nd preservation in lenti cular calcareou s concretions e mbed ded
in well-laminate d mud stone at Loc. TP-613 , Mf-h m ember [middle Cenomanian] in th e T a ppu area. Thick lin e:preserv ed sh ell ; thin , dash ed lin e: dissolv ed she ll ; shadow: calcareou s co nc retion (same as in Figure 4).
A: A l1agaudry ceras sacya.
B: Desmoceras (Pseudouhligella) japol1icu m.
Oil ier whor l p reserved[JIl l co ll apsed

Up.

t

lelll
Inn er whorl dissolved

Figure 4 .
Mode of ammonit e occurrence andprese rvation in a lenticular calc,lfcous co ncretion elllbedded in weak ly bioturbated mud stone at Loc. TP617 , Mf-h m ember [middle Cenomanian] in the Tappu
area. An adult shell of Desmoceras (Pseudouhligella)japol1icum.

served. Ammonite-bearing calcareous nodules
embedded in this Planolites mudstone takeelliptical shape, and contain several well pre served immature shells of Tetragonites glabrus
and Tragodesmoceroides subcostatus. In usual,
their shells lay horizontally, but in some case,they do not show any preferred orientation in

the calcareous nodules. Living chambers of suchammonites are usually collapsed , but their inner
whorls are well preserved .
Occurrence in the middle Turonian to theupper Santonian: In the upper stratigraphic
levels (Ml-o to Uk) , mudstone is usually intensely
bioturbated , and one calcareous concretion
yields usually abundant fossils which are fairly
well-preserved and show random orientation in
the concretion. Such fossiliferous calcareous
concretions thicken vertically and show a spherical or characteristic mushroom shape. Figure 5
is an example of amm()nite occurrence in amushroom-sha ped calcareous concretion embedded in intensely bioturbated mudstone at
Loc. TP-080 (Ud-e member; lower Santonian ;Figure 2). Tetrago nites glabrus and Dam esites
damesi of various growth stages are scatteredin the concret ion without any preferred orientation. Most of them are found in a good stateof preservation, except for the partial collapseof the living chamber. Air chambers are filledwith sparry calcite, but the shell wall , septa

290

Haruyoshi MAEDA

Up .

\

Figure S. Mode of ammonite occurrence in amushroom-shap ed calcareous concretion emb edd ed inintensely bioturbated mudstone at Loc. TP-080, Ud-e
member [lower Santonian) in th e Tappu area. Keeledammonites: Damesites damesi ; smooth-shell ed ammonites: Tetragonites g/abrus. Many shell fragments ofPo/y ptyc!Joceras sp. and Inoceramus (Sphenoceramus)
naulnanni and num erou s plant remains are concentrated
in th e lower part of th e concret ion.

and siphuncular tube have been completely
remained. In addition to moderate-sized ammonite shells, numerous immature ammonites,. less than I cm in diameter occur with their
protoconch preserved in the same calcareous
concretions, in association with abundant plantremains. The mushroom-shaped calcareous concretions exhibit interesting mode of fossil occurrence. The lower part in these concretions contains numerous small-sized ammonites andInoceramus together with abundant plant remains. On the other hand, the middle to upper
part is characterized by sporadical occurrenceof larger ammonite shells, and sometimes no
megafossils occur in the upper part. Throughout
the Cretaceous succession of the Tappu area,
the occurrence of fossils are more abundant incalcareous concretions in almost massive or
bioturbated horizons than in well-laminatedpart. The tendency for the stratigraphic change

in the mode of ammonite preservation in th(
Tappu area seems to recognize in other areas ir
Hokkaido.
Discussion: In the upper Cretaceous of Hokkaido , megafossils occur abundantly in calcare·ous concretions. Accumulated fossils in nodule~
are usually well preserved in contrast to the rare
and poorly preserved occurrence in surrounding
mudstone. There are following two interpretations on such mode of occurrence .
(A) : Molluscan shell remains were at first
distributed homogeneously in the sediments,
and after the formation of calcareous concretions, those in the surrounding rocks had been
selectively dissolved away during diagenetic
process.
(B) : Molluscan shell remains were originallyaccumulated as patches at places on the sea
floor , and calcareous concretions were formed
around the accumulations of the shell.
In practice , dissolution of shell is frequently
observable in ammonite remains which areextended from calcareous nodule to the surrounding mudstone. Figure 6 shows an example
of a shell of Desmoceras (Pseudouhligella)japonicum at Loc. TP-606 (Mf-h member; upper
Cenomanian). In this case , the shell is well preserved in the calcareous concretion , whereas,
it is completely dissolved away in surrounding
mudstone. The mold of dissolved shell is notobservable at Loc . TP-605 , while it is recognizedin some other cases. This mode of occurrence
seems to support the interpretation (A).
Different interpretation is obtained fromobservation of distributional pattern of plantremains in calcareous concretions and surrounding rocks at various stratigraphic levels. At theoutcrop, plant remains are not distributed
homogeneously but likewise accumulated in thecalcareous concretions . There are some calcareous concretions composed mostly of considerable amount of plant remains without megafossils , while plant remains are extremely rarein the surrounding mudstone (e.g. Loc . TP-004 :upper Turonian) . Plant remains, particularly
wood particles, seem to be stable in diagnetic
dissolution for very fine carbonaceous flakes are846.

dissolved\,-

Taphonomy of ammonites from Hokkaido

291

~----

/

I

I
(

I

I
I

\
\

lcm

I

\
I

I"

Figure 6. Mode of occurrence of Desmoceras(Pseudouhligella) japonicum, which is extended from
calcareous concretion to the surrounding mudstone, atLoc. TP-606, mf-h member [upper Cenomanian] in the
Tappu area.

observable in the mudstone. In addition, casts ormolds of shell should be preserved in the mudstone if they are dissolved during diagenesis.
Such molds or casts are, however, rare in the
mudstone except in the circumference of calcareous concretions. It seems natural that theshells and the plant remains were originally accumulated at places on the sea floor, and calcareous concretions were subsequently formed
around such accumulations. The accumulatedshells out of calcareous concretions might dissolved during post-depositional diagenetic process.
Co-occurrence of ammonite shells and plantremains : In both calcareous concretions andsurrounding rocks, co-occurrence of ammonites
and plant remains seems very interesting. It is
not peculiar to the restricted horizons in the
Tappu area but is frequently observable invarious stratigraphic levels throughout the Cretaceous sequence in Hokkaido. Co-occurrenceof ammonites and plant remains in the upper
Albian in the Ikushumbetsu area is shown in
Figure 7. In this case, about fifteen individualsof Mortoniceras (Deiradoceras) sp., Zelandites
sp. and anisoceratid heteromorph are accumulated on a bedding plane of aobut 40 cm x 40
cm together with large wood trunk. A fragmentof aptychus was associated with the assemblage,

Figure 7. Co-occurrence of ammonites and plantremains in well-laminated mudstone at Loc. IK-1006[upper Albian] in the Ikushumbetsu area. Shells ofMortoniceras (Deiradoceras) sp. (ornamented ones),
Zelandites sp . (smooth-shelled one) and anisoceratid
heteromorph are accumulated on a bedding plane ofabout 40 cm x 40 cm together with large wood trunk.

but no ammonite shells were found with jaw
apparatus in situ. They may show allochthonousmode of occurrence, for their living chambers
are somewhat damaged by transportation. Similar accumulations, composed of ammonite shells
and plant remains, are scattered as patches atplaces on a bedding plane. Because no calcareous
concretions are formed around the locality,
preservational bias, originated from partial
calcification of sediments, can be neglected in
the case. Such mode of occurrence, which is
not peculiar to the Yezo Group (e.g. Maeda,
1987: Monobegawa Group [Albian] etc.), maysuggest that ammonite shells together with plantremains were transported and accumulated as
patches on the sea floor by weak bottom currents.
After death, ammonite shells might have
rapidly become waterlogged (Kennedy andCobban, 1976). Density of waterlogged ammonite shells were much smaller than those ofbivalve and gastropod shells, judging from theextremely thin shell tests. Also a part of camera
in many shells was probably free from water-

Haruyoshi MA1:.1JA

292

flooding. Possibly , its density may be quite
similar to those of waterlogged wood particles(about l.11 to l.23 g/cm 3 ) or plant remains.
If so , it seems quite natural that the waterlogged
ammonite shells and plant remains behave hydro·
dynamically similar way. Their mode of occurrence may suggest that they were similarly transported easily by very weak bottom currents, andthat they were finally deposited at the sameplaces on the sea floor.
The shells of ammonite and inoceramid are
in usual randomly orientated in the calcareous
concretions embedded in intensely bioturbatedmudstone of upper stratigraphic levels (Figure
5 ; Gill and Cobban, 1966). Taking the co-occur·
rence of benthic body fossils and burrows into
consideration, such random orientation of shells
in the upper members are possibly atrributed
to the intense bioturbation by shelled and nonshelled deposit feeders. In all probability , deposit feeders, such as spatangoids, disturb thepreferred orientation of ammonite shells on thesea floor or in soft sediments.
Preservation of large ammonites
Large ammonites , attaining more than 30 cm
in diameter are quite abundant throughout the
Yezo Group. Moreover, gigantic ones (exceeding 1 m in diameter) are commonly found at
various horizons. They are puzosiids [late Albian
to Coniacian] , pachydiscids [Santonian to
Maastrichtian] and other groups. In comparison
with moderate sized ammonites, large ammonites
exhibit peculiar mode of occurrence and preservation. They usually occur solitarily and lie
horizontally in mudstone. In many specimens,
the siphuncular tube is damaged, and inside of
the shell, both living chamber and phragmocone ,are filled with mud. "Draught-through effect":~ Figure 8.

a mechanism of sediment filling into phragmocone chambers , was experinlentarily revealed
by Seilacher (1969). Sediment-infillings are
somewhat calcified . Some large shells form single
calcareous concretions themselves . They are
generally more poorly preserved than the moderate-sized ammonites, even they occur in calcareous concretions. As stated before, moderateto small-sized ammonites are well-preserved in
the intensely bioturbated middle Turonian toSantonian mudstone. In contrast to this, largeammonite shells are more or less damaged
throughout the Cretaceous sequence in Hokkaido. This evidence suggests that taphonomic anddiagenetic factors seem to be more influential
on preservation of large ammonites than on themoderate-sized ammonites.
Figure 8 summarizes typical mode of occurrence of large puzosiid ammonites (phragmocone) in the middle to upper Turonian sequenceof the Tappu area. Among the illustrated preservational types, selective dissolution of inner
whorls (Figures 8B, 9-2) is most frequently observed in large specimens of puzosiids, pachydiscids and acanthoceratids. Especially , many
Santonian Anapachydiscus and Eupachydiscus
shells have suffered dissolution of inner whorls
even in the case of less than 15 cm in shell diameter. On the contrary, inner whorls are generally well preserved in gaudryceratids . For
example , specimens of Gaudlyceras denseplicatum, which attains 30 cm or greater in diameter,are sometimes found with well-preserved inner
whorls. ~ dryceratid shells may be much
resistant against diagenetic dissolution because'outer surface of their shells are iliickly cCiatea~eriOsti'acum film (Birkelund , 1981L
Crush of the upper shell region (Figure 8C)
is also fairly common in preservation of largeammonites. In the case of large shells of Meso-

Typical mod e of preservation of large puzosiid phragmo cones in the middl e to upper Turoniansequ ence of the Tappu area. In many case, several typ es of preservation are combin ed in a sp ecim en.
A:
Original shell-morphology .
8,8': Selective dissolution of inner whorl s.
C:Crush of upper sh ell region.
0:"Half-ammonite" preservation.
E, E' : " Ventral-tire" preservation .

293846. Taphonomy of ammonites from Hokkaido

"

\

/

I

. . ~/,2:<~~. . ..
,

E

294

Harnyoshi MAEDA

puzosia pacifica, upper flank: about one third
portion of the whorls, has been selectively collapsed and sank into the inner side of the whorls
in post-burial diagenetic process. Longitudianlfracture patterns, such as umbilical fracture(Seilacher et at., 1976), are well-observable, but
their exact patterns are peculiar to ammonite
shell-geometry as stated by Seilacher et at.
(I976). Both living chamber and septate phragmocone have suffered this kind of post-burial
compactional deformation. As to be stated later,
dissolution of septa occurred at first, and it
might trigger the crush of phragmocone.
Figure 8D is another kind of preservation("half-ammonite" preservation: Seilacher et at.,1976, p. 349), that the upper half of the horizontally lying shell is dissolved, retaining only
the lower side. This mode of preservation is also
well-observable in the Yezo Group in various
taxa. I will discuss this problem later.
Among the various kinds of preservation
shown in Figure 8, Type (E) seems to be themost eccentric (Figures 9-2, 3a, and 3b). The
ammonite shell is preserved its venter and outerflanks of the last or last second whorl only, andinner flanks and umbilical margins are dissolved
away. Its appearance just looks like a "tire"(it is not clear whether such "ventral-tire"belongs to "tube" type or to "tubeless" type).
This "ventral-tire" preservation has not hitherto
described, although it is fairly common in large
puzosiids, pachydiscids and acanthoceratids in
the Cretaceous strata of Hokkaido. The marginof such "ventral-tire" is distinct, and preserved
portion of "ventral-tire" is distinct, and preserved portion of "ventral tire" is quite uniform.
In the case of Mesopuzosia pacifica specimens,for example, ventral 30 to 40% portion of lastwhorl, which is correspond with shell-involutionof this species, is uniformly preserved. Judging
from this, the preserved ventral part might beoriginally covered with outer whorl of the shell.
Only the ventral part, thus not exposed directly
to the external environment, might be free from
dissolution of shell during diagenesis.
In practice, several types of preservation are
combined in a specimen (Figure 9-2).
Discussion: I will concentrate my discussion
on the preservational history of "half-ammonites" in the Yezo Group. "Half-ammonite"preservation (Figure 8D) has been already recognized by many scholars in the various Mesozoic strata in the world. Roughly speaking, thefollowing three explanations have been presented
for the preservational history of "half-ammonite" (Figure 12).
(1) "Cast on sea floor" model: A half-buriedammonite shell had been dissolved away withthe sea water during diastem, and the shellimpression was preserved as an external cast on
consolidated substrata of the sea floor (Minato,
1953: Triasic Inai Group, Japan).
(2) "Exposed upper-half' model: The lower
half of a horizontally lying ammonite shell wasburied in mud. The upper half was still exposed
above sediment surface, and thereafter exposedpart with sea water had suffered pre-burial dissolution in sediment-water interface (Hollmann,
1962: Jurassic Ammonitico Rosso, Italy; Lehmann, 1976; Tanabe et at., 1984: Jurassic
Toyora Group, Japan, etc.).
(3) "Post-burial dissolution" model: The upper half of a completely buried ammonite shell
had suffered selective shell-dissolution withinterstitial water because of the partial sedimentary filling (Seilacher et at., 1976: Jurassic
Posidonienschiefer, West Germany, etc.).
Among them, hypothesis (1) should be re-----+ Figure 9. la, b. Large Canadoceras multicostatum Matsumoto associated with a spatangoid in the lower
umbilical void. UMUT.MM-6862; Campanian; Naibuchi area, Sakhalin. la: Lateral view; xO.28. 1 b: Close-up ofumbilical void of la. Well preserved spatangoid shell filled with sparry calcite is indicated by arrow.
2. Mesopuzosia pacifica Matsumoto showing selective dissolution of inner whorls (most inner part) and"ventral-tire" preservation (indicated by arrow). KSG-HM. 1012; Loc. TP-3024, Ml-O member [middle Turonian] in the Tappu area; xO.S2.
3a,b. Anapac/zydisclls slItneri (Yokoyama) showing "ventral-tire" preservation. UMUT.MM-6783; Santonian; Naibuchi area, Sakhalin; x0.44. 3a: Ventral view. 3b: Lateral view.

846. Taphonomy of ammonites from Hokkaido

295

Harnyoshi MAEDA

296

jected in the case of "half-ammonites" from theCretaceous Yezo Group, because calcified shellwall and septa actually remain in the lower half.
Hypothesis (2): illustrated in Figures 12A, B, F,
seems attractive, for large shells of ammonite
might spend much time for their full-burial in
the sediments. As a natural consequence, theymust have suffered many kinds of diagenetic
destruction before their complete burial. But asstated later, there are some problems to explain
the practical mode of "half-ammonite" preservation in the Yezo Group by this model.
According to my field and laboratory observations, mode of preservation of many specimens
represents an intermediate stage between thetypes of the upper surface crushing, and "halfammonite" preservation (Figures 8C, D). In these
specimens, outer shell wall and septa in theupper half have suffered not only crushing but
also partial dissolution. These features suggest
us that the stage of crushing of the upper surface
grades into the stage of "half-ammonite" preservation in the process of post-burial diagenesis.
It is noticeable that many ammonites exhibit
two different states of preservation even in thesame specimen : namely, "half-ammonite" phragmocone and crushed living chamber. Typicalexample of such case is given in Figure 10 (Loc.
Upl'last septum-

Figure 10. A shell of Mesopuzosia planulatiformis
showing two different states of preservation, which arebounded by the last septum, in a shell. Loc. TP-50l ,uppermost part of Mj-k member [middle Turonian),
Tappu area.

TP-SOl ; Mj-k member; middle Turonian in the
Tappu area), in which two different phases ofpreservation are sharply bounded by the last
septum are observable in a horizontally embedded shell of Mesopuzosia planulatiformis.
The specimen retains a living chamber filled withmud. The upper side of the living chamber ispartly crushed by compaction, but remains shellmaterial (Type C preservation of Figure 8). On
the other hand, the phragmocone shows a quite
different mode of preservation from living chamber. Namely, its upper side had been collapsed
and flattened. Some collapsed fragments of theupper flank , particularly of inner whorls, hadbeen partly dissolved (intermediate features
between Types C and D in Figure 8). Inner
whorls of phragmocone actually lack the upper
half. Septa, except the last one, had suffered
more intense dissolution than the other part ofthe shell. As calcified shell wall and sutures arepreserved in the collapsed upper flank of many
specin1ens, dissolution of septa had occurredprior to that of upper flank (Figures 10, 11). If
shell dissolution did occur before complete
burial of the shell, upper flank exposed in thesea water should dissolve at first. In addition tothis, "exposed upper half' model cannot explainsuch drastic difference in the mode of preservation between phragmocone and living chamber(Figures 10, 11).
The preservational uniformity of "half-ammonites" puzzles us very much. I have observed atleast two hundred "half-ammonite" specimensfrom the Upper Cretaceous deposits in Hokkaido and Sakhalin. In spite of a wide variety intheir locations, horizons, taxonomic positionsetc., the mode of "half-ammonite" preservation
are quite similar among them. "One third ammonite" or "three-quarter ammonite" preservations
are scarcely found. "Two third ammonites" aresometimes observable, but careful examination
reveals that they should belong to Type C preservation, i.e. for their upper flanks (=upper~ Figure 11. la-c. Photostereograph of a specimen of Mesopuzosia planulatiformis (Jimbo) showing two
different preservational states, which are bounded by th e last second septum. KSG-HM. 1011; Loc. TP-50l,
uppermost part of Mj-I< member; middle Turonian; Tappu area; xO.78 . l a: Lateral view (upper side). lb: Ventral
view. lc: Lateral view (lower side).

846.

Taphonomy of ammonites from Hokkaido

297

298

Han/yoshi MAEDA"one third") are merely broken by compaction.
"Exposed upper half' model cannot, thus, explain such preservational uniformity observed
in "half-ammonites" from the Cretaceous of
Hokkaido and Sakhalin. If shell dissolution occurred directly with the sea water before complete burial, the ammonite shells would not need
necessarily showing exact "half-ammonite" preservation, but should exhibit various stages ofdissolution: for example, "one third ammonites"or "three-quarterammonites". Tanabe et al.
(1984) studied mode of "half-ammonite" preservation embedded in the Liassic laminated blackshale of the Toyora Group, southwest Japan.
They attributed "keel" of harpoceratids to prevent the upper half of the shell from sinking
down into soft sediments, and to stabilize the"half-ammonite" position on sediment-waterinterface during dissolution of the upper half.
Their taphonomic model in the Liassic blackshale, however, seems to be inapplicable to the"half-ammonites" from the Cretaceous depositsin Hokkaido. The most "half-ammonites" in
the Cretaceous Yezo Group are non-keeled ones
as represented by puzosiids and pachydiscids.
In the case of "half-ammonites" from Hokkaido, their phragmocones are similarly preserved
from lower flank to the extent of ventral area
just exceeding the median line: i.e. just above
the position of siphuncle or septal neck. Theirliving chambers are sometimes preserved better
than the phragmocones. Their preservationalfeatures may suggest us that the mode of "halfammonite." preservation is not prescribed bytheir "half-burial" on the sea floor but muchdecisively by internal structure of phragmocones,
which easily raise the partial sedimentary filling.
As Seilacher (1969) demonstrated experimentally, sediments can enter phragmocone if
siphuncular tube and somewhere of the whorl
were damaged. The sediments were predominantly transported into the chambers of thelower phragmocone by "draught-through" current. The current can piled them up even until
higher level than median line in inter-septal area,
however, the sediments cannot be deposited
exceeding the level of septal neck near the septal

area in order to ensure the passway of "draughtthrough" current. The surface of lower chambers
might be sealed with sediments, whereas, thoseof the upper and septa remainded being exposedin the sea water, and even in interstitial water
after full-burial of the shell. "Half-ammonite"preservation in the Yezo Group may not be
Originated from "external" half-burial of theshell on the sea bottom but "internal" halfburial prescribed by the septal neck position
which is phylogenetically determined even almost all planispiral ammonites. If so, it seems
natural that "half-ammonite" position is quite
uniform among many specimens observed.
Practical mode of "half-ammonite" preservationin the Yezo Group may suggest that "post-burial
dissolution" model (Seilacher et aI., 1976: thethird hypothesis) is the most convincing explanation.
Figure 12 summarizes presumable taphonomic
history of "half-ammonites" in the Yezo Group.
(1) A dead ammonite shell settled horizontally down on the sea floor (Figure 12A).
(2) Before complete burial of the shell, thinshelled inner whorl dissolved away with the sea
water, and siphuncular tube, composed of organic-rich material, was broken. Then, "draughtthrough" current transported soft sediments into
the phragmocone chambers through septal necks,
and piled them in the lower part of the chambers(Figure 12C). "Draught-through" current might
continue until sediments closed its entrance orpathway, or exit (for example, apertures ofliving chamber, septal necks in phragmocone,and dissolved inner whorl respectively).
(3) After full-burial of the shell, the living
chamber was completely filled with sediments,
and the last septum was perfectly sealed withthem. On the other hand, phragmocone chambers remained in half-buried state, and theupper half and septa had been still exposed ininterstitial water. Then dissolution of fully naked
septa, without any kind of sediment sealing,
began (Figure 120), and the dissolution of theupper half might follow this. Dissolution of septa
could occur before full-burial of the shell (Figure
12C).

846. Taphonomy of ammonites from Hokkaido

299

draught-throughcurrent

last septum

I

E

Figure 12. Presumable taphonomic .history of "half-ammonite" in the Upp er Cretaceou s Yezo Group.
(Explanation in th e tex t).

(4) The dissolution of septa triggered collapseof the upper half of phragmocone chambers,
remained empty, by compaction. On the other
hand, the living chamber and the last septum,
both of which were sealed with sediment infillings and were almost free from dissolution, might
be much resistant against compaction. In tllis
way, two different states of ammonite preservation, which were sharply bounded by the last
septum, had been formed (Figure 12E).
(5) During diagenesis, crushed shell-materials
had been dissolved away, and "half-ammonite"preservation, particularly well-observable in thephragmocone, was accomplished (Figure 12F).
There are many factors concerning the preservation of ammonites. The preservational statesof ammonites may be controlled by the interaction between the factors for destruction andthose for preservation. In addition to the post-

mortem processes mentioned above, shell dissolution could occur since ammonites were still
alive, particularly in the case of large ammonites.
Further precise observations are needed toanswer the problem.
Mode of co-occurrence of large ammonites,
plant remains and spatangoids
As states above, ammonite shells and plantremains seem to had accumulated as patches atplaces in the Yezo Group. I could not realize
the exact mechanism to form such accumulations
on the sea floor, but the following interesting
mode of occurrence of large ammonite Mesopuzosia planulatiformis from the middle Turonian of the Tappu area (Ml-o member) may suggest about it (Figure 13). The specimen, about
70 cm in diameter, was found to form a calcare-Han/yoshi MAEDA

300

Up.

~

-

lOcm

Figure 13. Mode of occurrence of large Mesopuzosia plallulatiformis associated with small shell fragmentsof Inoceramus hobetsellsis and numcrous plant remains around thc shell and in the lower umbilical void. Loc.
TP-514, MI-o member [middle Turonian], Tappu area.

ous concretion itself. A considerable amount of
disarticulated immature shells of Inoceramus
hobetsellsis of about 2 to 5 em size and plantremains occur together in the underside of theammonite shell. They are accumulated aroundthe marginal area of the ammonite shell, and are
the most concentrated in the lower umbilicalvoid where sediments are bioturbated and contain many fecal pellets of 2 to 4 mm in diameter(Figures l3, 14). The shell of Mesopuzosia probably triggered off such accumulation acting as a
"trap" on the sea floor. The inoceramid shells
and plant remains might be transported by bottom current, and accumulated around the shell.
Similar occurrence of a large ammonite andplant or small inoceramid shell remains are observable at many stratigraphic horizons in the
Cretaceous of Hokkaido. In addition to this,small ammonite shells sometimes occur with theliving chamber of a large ammonite. Wright(1935), Casey (1961) and Lehmann (1976) also
reported the same type of ammonite occurrence. This type of ammonite occurrence can bealso attributed to the same biostratinomical
process (Maeda, in preparation).
In relation to this type of accumulation, many
spatangoid sea urchins show a peculiar mode ofoccurrence in the lower umbilical voids of theflat lying large ammonite shells. Considerable
amounts of shell fragments and plant remains

are accumulated in the portion. Figures 9-1a, b
show an specimen of Calladoceras multicostatumfrom the Campanian of Naibuchi area, Sakhalin.
The spatangoid shell is so perfectly preserved in
the lower umbilical void of the ammonite thatsparry calcite crystals fill completely the insideof the shell without any sediment in fillings.
Furthermore, many well-preserved spatangoids
occur in the lower part pf the spherical or mushroom-shaped calcareous concretions where numerous shells of ammonites and inoceramids,
and plant remains are concentrated (e.g., Loc.
TP-409, Uf member; lower Santonian). In bothcases, the heart urchins are well preserved in thecalcareous nodules, and may exhibit indigenousor even in situ mode of occurrence. In modern
environments, dead shells of spatangoids arequite easy to break. It is, therefore, strongly
postulated that in the above described spatangoids they had fossilized almost in the living place.
Indeed, many horizontal burrows made byspatangoids can be observed in a tuff bed justbelow the sea urchin-bearing calcareous nodulein the lower Santonain sequence in the Tappu
area. Similar mode of occurrence of the spa tangoids in nodules was also described by Reeside
and Cobban (1960) in the Albian of the WesternInterior region.
The place where many shell fragments andplant remains accumulated as patches on the sea-+ Figure 14. I a, b. Accumulation of molluscan shcll fragments and plant remains in the lower umbilical voidof large Mesopllzosia planlliatiformis. KSG-HM. 1013; at Loc. TP-514, MI-o member [middle Turonian] in the
Tappu area. la: Vertical profile. Many plant remains (dark-colored part) and fecal pellets arc observable. 1 b:
Horizontal view from lower side (indicated by arrow). Disarticulated immature shells of Inoceramus IlObetsellsis
arc accumulated in their convex-side down. (Figures of natural size)

846. Taphonomy of ammonites from Hokkaido

301

Haruyoshi MAEDA

302

A

B

c
Figure I S. Poss ibl e bi o stratin o mi ca l process of large amm o nite she ll assoc ia ted with a spa ta ngo id in th elower umbilica l vo id. A : A large amm o nite shell triggered o ff t he accumul a tio n o f mo llu sca n she ll fragm ent s andpla nt rem a ins in t he lo wer umbili ca l vo id and aro und th e shel l ac t ing as a " tra p" o n the se a fl oo r. Depos it fee d·ing spata ngoid asse mbl ed to th e pl ace of such acc umul at io n to feed eutrop hic se dim e nts. B: Aftc r th e spa ta ngo id
die d in situ , th e large a mm o nite shell was buried co m ple te ly w ith so ft se d im e nts . C: Seve ral d iage ne ti c processes
influ e nced t he preserva ti o n of fo ssils. Th e la rge amm o nit e shell fo rm e d single calcar eo us co ncret io n.

f1 00 r see ms to be rich in organic matters. I presume that the deposit-fee ding spa tangoid s asse mbled to the place of accumulation of shells
to fee d eutrophi c se diments: particularl y to thelowe r um bilical void of large amm oni te shell ,and then died in situ. Th e above possible bi o·stratinomi ca l process of spata ngoid test is diagramat ically shown in Fi gure 15. It see ms interesting that only one spata ngoid is generall yfound in the lowe r umbili ca l void of a large
amm onite shell , while two o r three are so metimes agg rega te d in a mush roo m-sha ped calea re-846. Taphonomy of ammonites from Hokkaido
ous concretion.
Conclusion(1) Numerous ammonites are found in calcareous concretions or surrounding mudstone in
the Cretaceous deposits of the Tappu area, Hokkaido. Their detailed modes of occurrence andpreservation are quite different by sedimentaryfeatures of mudstone and by their size.
(2) Flat, lenticular calcareous concretions are
dominant in well-laminated mudstone of thelower to middle Cenomanian. Ammonite fossils
in such concretions are, in general, poorly preserved. Collapse and dissolution of ammonite
shells suggest that the concretions had consolidated in later stage of diagenesis.
(3) In contrast to this, spherical or mushroom-shaped calcareous concretions, which yield
usually many well preserved ammonites including immatures, are abundant in intensely bioturbated mudstone of the middle Turonian toupper Santonian. The concretions embedded in
the part might had formed in earlier stage ofdiagenesis before ammonite shells suffered com-303

paction and dissolution. Figure 16 summarizes
these features. Not only overburden of thesediments but also organic and inorganic sedimentary conditions of the sea floor at that time;e.g. degree of bioturbation, might have influenced the diagenetic factors.
(4) Ammonite shells and plant remains frequently occur together as patches. Waterlogged
ammonite shells and plant remains might hydrodynamically behave similar way, and had beentransported by weak bottom currents to thesame place.
(5) Large-sized ammonite shells are usuallymore incompletely preserved in calcareous concretions than those of moderate-sized ones asrepresented by peculiar mode of preservationsuch as "half-ammonite" and "ventral tire".
Degree of sediment-covering might· have influenced to the mode of large-sized ammonite
preservation.
(6) Quite uniform "half-ammonite" preservation in the Cretaceous of Hokkaido cannot explained by the half-burial model on the sea
floor but "internal half-burial" model of phragmocone by "draught-through" currents. The

Mj-kMI-o"-Uk
Mf-h
Mb"-Mf-h(i.btrb.ms.)(Plan.
ms.
)
('II.
btrb.
ms.
)
(lam. ms.)
• PRE.SE fWAlIO NALdSIAl£Sdj;
LOFL.AMMONLTE.SIi!
06.
Perfect
Only I iving chamberco I lapsed
Phragmocone col lapsed
Shel I dissolved

Formation of
calcareous concretion

0: abundant

6.

0

0

0

6.

0

0

6.

early
stage

late
stage

6.:

common0- : rareFigure 16. Summary on mode of preselvation of moderate-sized ammonites in calcareous concretions.

Hanlyoshi MAEDA

304

preservation seems to be prescribed by the septal
neck position, which is phylogenetically fixedin almost all planispiral ammonites.
(7) Large ammonite shell probably triggered
off the accumulation of shell fragments and plantremains, acting as a "trap" on the sea floor. They
had been particularly concentrated in the lower
umbilical void of the large ammonite shell. Some
spatangoids, preserved regularly in such umbilicalvoid of large ammonite, might assemble to eat
organic matter accumulated there.
Acknowledgments
I wish to express my sincere thanks to Professor Tetsuro Hanai (Osaka Gakuin University) for
his encouragements during the course of thiswork. I am also much indebted to Professor
Kiyotaka Chinzei (Kyoto University) for his
helpful discussion both in the field and laboratory. Thanks are extended to Dr. Kazushige
Tanabe (University of Tokyo) for his criticalreading of the manuscript and giving me usefulsuggestions, Professor Itaru Hayami (Universityof Tokyo), Dr. Tomowo Ozawa (Nagoya University), Dr. Toshiyuki Yamaguchi (Chiba
University), Professor Masayuki Tashiro and Dr.
Makoto Okamura (Kochi University) for theirvaluable suggestions. I am also grateful to ObiraTown Office and Tappu Forestry Office for theirco-operation in the field, and to Mr. and Mrs.
Okuno, and Mr. and Mrs. Saito (Boyodai Youth
Hostel) for their kind assistance during my fieldsurvey. Without assistance mentioned above, I
could not publish my study. This study waspartly supported by the Grant-in-Aid for Cooperative Research (No. 61480028) of the
Ministry of Education, Science and Culture,
Government of Japan.
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Casey, R. (1961): The stratigraphic palaeontology of
the Lower Greensand. Palaeontology, vol. 3, pt.

4, p. 487 -621, pis. 77 --84.
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section of the Upper Cretaceous Pierre Shale in
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(1959): Zonation of the Upper Cretaceous in
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plate tectonics. Earth Monthly, no. 1, p. 869-877(in Japanese).
--(1983): Collision orogenesis and sedimentation in846. Taphonomy of ammonites from Hokkaido
Hokkaido, Japan. III "Accretion Tectonics in tile
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Publishing Co., Tokyo.
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formations in the United States and Canada. U. S.
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Seilacher, A. (1969): Sedimentationprozesse in Ammoniten. Akad. Wiss. u. Lit., Mainz, vol. 9, p. 191203.
- - , Andalib, F., Dietl, G. and Gocht, H. (1976):
Preservational history of compressed Jurassic
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305

Tanabe, K. (1979): Palaeoecological analysis of ammonoid assemblages in the Turonian Scaphites Facies
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609-630.
and Ohtsuka, Y. (1985): Ammonoid early internal
shell structure: its bearing on early life history.
Paleobiolgoy, vol. 11, no. 3, p. 310-322.
- - , Inazumi, A., Tamahama, K. and Katsuta, T.
(1984): Taphonomy of half and compressed ammonites from the Lower J urassie black shales of
the Toyora area, west Japan. Palaeogeogr. Palaeodim. Palaeoecol., vol. 47, p. 329-346.
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HiJB3iJi!f J§tTrans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 306-323, 9 Figs., December 30,1987

847. BURROWING DEPTH OF INFAUNAL BIVALVES - OBSERVATION OF
LIVING SPECIES AND ITS RELATION TO SHELL MORPHOLOGY*YASUO KONDO
Department of Geology and Mineralogy, Faculty of Science, Kyoto University,
Kitashirakawa, Kyoto 606

Abstract. Burrowing depths of 22 infau nal bivalve species living in the Japanese coastal
areas were observed. Burrowing depth of each species is variable depending on the shell size,
substratum, and other environmental attributes. The most striking is ontogenetic variation:
In most species, maximum burrowing depth tends to increases with the increase of shell size.
Difference in burrowing depth among species represents different life habit in bivalves.
Particularly, the difference is pronounced, between extremely deep burial (more than 30 cm) of
immobile bivalves like Pallopea japollica A. Adams and shallow burial (less than 15 cm) of mostbivalves capable of active movement.
In suspension-feeding siphonate bivalves, the ratio of pallial sinus length to shell length(Pallial Sinus Index) is closely related to the relative maximum burrowing depth. This "sinusdepth relation" may be useful in inferring burrowing depth of extinct species.

analyzing post-mortem processes operated during
the formation of shell beds (Aigner, 1982; Bloos,
1982; Kidwell and Aigner, 1985).
Previous authors have suggested that the difference in burrowing depth among infaunal
bivalves is one of the important factors in inferring the post-mortem processes of the fossil
bivalves. Conversely, if burrowing depth of agiven fossil bivalve is known, we can reconstruct
the realistic post-mortem processes, such as
reorientation by living organisms or sediment
reworking and subsequent transportation. It is,therefore, important to study relationship between burrowing depth and shell morphology
based on observation of burrowing depth ofmany Recent infaunal bivalves.
Systematic survey on burrowing depth and its
relation to shell morphology in the Bivalvia havenot been carried out except for the pioneer workby Stanley (I970). He discussed the relationshipbetween life position and shell morphology inmany living bivalve species from the Western
Atlantic. In his study, emphasis was laid onfunctional interpretation of the relation between

Introduction
Burrowing habit of bivalves is considered tohave developed extensively since Mesozoic(Stanley, 1968), to avoid disturbance by physicalagents and to escape from predators. Wide variation of burrowing depth seen among bivalves andother infaunal benthos was regarded as one of
the common biological solutions for resource
partitioning (Ausich and Bottjer, 1982, 1985), or
as different adaptive strategy of each species tophysical sedimentary environment.
The difference in burrowing depth among
bivalves, on the other hand, may bring aboutsome confusion in paleoecologic interpretationof fossil occurrences. Successive deposition andcolonization by bivalves with different burrowing depth apparently resulted in mixing of older
shallow burrowers and newer deep burrowers.
Some paleontologists have paid a special attention to differences between epi- and in-faunas,
and between shallow and deep burrowers in*Received October 8, 1987, read June 21, 1987 at
Fukui Prefectural Museum.

306

847. Burrowing depth of infaunal bivalves
life orientation and shell morphology. His data
were not sufficient to understand intra- andIinter-specific variations in burrowing depth, andnot enough to be used as a clue to reconstructburrowing depth of extinct ~pecies.
This study was undertaken to obtain basic
data on burrowing depth and its relation to shellmorphology in 22 infaunal bivalve species livingin the Japanese coastal areas. First, burrowing
depth of the bivalves is described with emphasis
on intra- and interspecific variation. Second,
pallial sinus length will be emphasized as a key
morphology for reconstruction of the burrowing depth. Description of life position as well asother life habit and habitat of the species observed are provided in the appendix.
Acknowledgments
This paper is the first half of the doctoral
dissertation submitted to the University ofTokyo. I acknowledge Profs. I. Hayami of the
University of Tokyo and K. Chinzei of Kyoto
University for their helpful discussions andadvice during this study. Thanks are also extended to Prof. Y. Iwasaki of Kumamoto University and Dr. S. Shimoyama of Kyushu University
who aided me in the field observation in sometidal flats in Kyushu. Dr. A. Matsukuma of the
National Science Museum allowed me to observeand measure specimens of Recent bivalves fromthe Western Atlantic. Drs. K. Tanabe of the
University of Tokyo, H. Kitazato of Shizuoka
University, S. Matsui of Utsunomiya University
and Prof. T. Okutani of Tokyo University ofFisheries gave me valuable comments on thisstudy. Members of the Misaki Marine Biological
Station of the University of Tokyo kindly provided the writer facilities for collection andobservation of the bivalves living nearby sea area.
Profs. I. Hayami and K. Chinzei, and Dr. K.
Tanabe greatly improved the manuscript.
Burrowing depth of Recent bivalves
Study area and method
Observations of bivalve life position was made307

in nature, as far as possible. Some intertidal
flats were, then, chosen for observation (Table1). Physiographic descriptions of the study areas
are briefly summarized in the appendix. Life
position of intertidal species was observed by
digging when the tide is receded. Subtidal anddeeper bivalves were dredged at some areas, andwere observed in the laboratory in the following
manner (Figure 1). They were permitted toburrow in a small vessel filled with native orsometimes exotic sediment. The vessel wasplaced in a large container filled with runningsea water. Life position of these species wereobserved by digging. A tetrapack, empty tall
paper box (7 cm x 7 cm x 19.5 cm in size) wasused for observation of deeper burrowers like
Dosinorbis japonicus (Reeve). The box was filledwith sediment, and the bivalves were placed on
the sediment surface. After achieving burial,
enclosing sediment was removed until the bivalves appeared. The tetrapack is quite conven'ient in removing the filled sediment, as it is easily
cut to open. For observation of Panopea japonica A. Adams, an extremely deep burrower, alarge bucket was used. As large individuals of
P. japonica cannot burrow by themselves, they
are placed on the bottom of the bucket in inferred life orientation. Then bucket was filled
gradually with sediment. Panopea japonica expands its siphon to cope with the elevating sediment surface. The bucket continued to be filledwith sediment until siphon extension stopped.
Maximum burrowing depth of this species wasmeasured in this condition.
Intraspecific variation
Among 22 infaunal bivalves observed, sufficient data have been obtained for the following
7 species to understand ontogenetic variation inburrowing depth: (Ruditapes philippinarum
Adams et Reeve, Cyclina sinensis (Gmelin),
Dosinorbis japonicus, Mactra chinensis Philippi,
M. veneriformis Reeve, Nuttallia olivacea (Jay)and Macoma con tabulata (Deshayes). Theirburrowing depths were measured as a distancefrom the sediment surface to the shallowest
point on a buried shell, which is the same asYasuoKONDO

308

Table 1. List of infaunal bivalve species observed in this study and study area.
Numbers in parentheses show study arcas in which thc observation was madc.
Species name (study area)
Areidae
Glycymerididac
Limopsidae

Cardiidae
Vencridac

Mactridae
Donacidae
Asaphidae
Tellinidae
Solenidae
Hiatellidae
Cuspidariidae
Laternulidae

Tegillarca granosa (L.) (6)GlycYllleris rotunda (Dunker) (3)Limopsis tajimae So\\'crby (4)Oblimopa japonica (A. Adams) (3)Crenulilil110psis oblonga (A. Adams) (4)Nel110cardiulll salllarangae (Makiyama) (3)Circe scripta (L.) (5)Meretrix petechialis (Lamarck) (8)GOlllphina veneriforl11is l11elanaegis (Romer) (7)Cyclina sinensis (Gmelin) (I, 5)
Dosinorbis japonicus (Reeve) (2, 3)
Ruditapes philippinarum (Adams et Reeve) (I, 2, 3)
Mactra veneriforl11is Reeve (2)M. chinensis Philippi (2)Chion kiusiuellsis (Pilsbry) (7)Nuttallia olivacea (Jay) (1)Macollla contabulata (Deshayes) (1 )M. incongrua (v. Martens) (5)Solen strictus Gould (2)Panopea japonica A. Adams (8)Cuspidaria Illacrophynchus Smith (3)Laternula lil11icola (Reeve) (1 )Study areas
1: intertidal muddy sand flat of Matsukawaura Inlet, Soma City, Fukushima Prefecture. 2: tidal flat and nearby
subtidal setting of the Obitsugawa River delta, Kisarazu City, Chiba Prefecture. 3: intertidal zone in Aburatsubo
Cove, Miura City, Kanagawa Prefecture. 4: bathyal muddy bottom in the innermost part of Suruga Bay. 5:
tidal flat of Tsuyazaki Inlet, Fukuoka Prefecture. 6: intertidal zone of sandy shore in Nata, Fukuoka Prefecture.
7: intertidal mud flat in Shioya, Kumamoto City, Kumamoto Prefecture. 8: observation of specimens purchasedin shops.

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847. Burrowing depth 0/ in/aunal bivalves
Stanley's (1970) definition.
I ntraspecific variation in burrowing depth
may be classified into three categories: (I) ontogenetic variation, (2) variation due to substratum
difference, and (3) variation due to other causes.
Ontogenetic variation: This is the most conspicuous among the variations of different categories in burrowing depth of a bivalve species.
All of the 7 species examined burrow more deeply as they grow large. Maximum burrrowing
depth of these species is roughly proportional toshell length. Observation on the intertidal sandflat of the Obitsugawa River delta (study area 2
in Table 1) shows that smaII individuals of R.
philippinanlm of about 1 cm in shell size, forexample, burrow 1.5 cm and intermediate individuals (ca. 2 cm) 3 cm (Figure 2). On the basisof this proportional relationship, maximum
burrowing depth (D) in relation to shell length(S) of R. philippinarnm can be expressed asfollows.
D = 1.5 S
Similarly, those of C. sinensis and N. olivacea
can be expressed as:
D = 1.3 S (c. sinensis)
D = 3.9 S (N. olivacea)
This proportional relationship between maximum burrowing depth and shell length is quite
reasonable, because the extended siphon length,
which is comparable to maximum burrowing
depth, increases with growth. Difference inmaximum burrowing depth among the species
examined will be stated in the next section, on
the basis of this relationship.
In most species, however, the relationship iswell applicable only to relatively small-sizedindividuals. For example, small-sized individualsof D. japonicus, up to 2 cm in shell length,
burrow 5 times their shell length, while an individual of 6 cm can burrow only twice the shelllength (12 cm).
Such "allometric shallowing" of burrowing
depth is commonly recognized in other species,
including R. ph ilippinarul1l , M. veneri/ormis
and M. chillensis. Stanley (1972) reported amore conspicuous example in Mercellaria l1lerceIlaria (L.): Young individuals (ca. 3-4 cm in

309

Ruditapes philippinarum

SHELL LENGTH (L) (em)24,......2

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v. f. sand (Obitsugawa River delta. Chiba Pref.)... muddy sand (Matsukawaura Inlet. Fukushima Pref,).0 pebbly sand (Aburatsubo Cove. Kanagawa Pref.)Figure 2. Intraspecific variaiton in burrowing
depth of Ruditapes philippinarum in relation to ontogenetic change and substratum difference. Black symbols indicate measurements in nature and open onesin the laboratory tank.

shell length) burrow at 5 cm below the sedimentsurface, while large (6-7 cm length) ones lessthan 2 cm in depth. He explained this from theviewpoint of functional morphology: Small
individuals are vulnerable to strong current andpredators so that they must burrow as deeply
and quickly as they can, while larger individuals
which are hydrodynamically more stable andless vulnerable to predators need not to burrow
so deeply.
Variation due to substratulIl dUference: Thisis one of the important factors controlling theburrowing depth of living bivalves, although it is
not well observed in many species. Most notable

310

YasuoKONDO

example was obtained for R. philippinanllll. In
a very fine sand of the Obitsugawa River tidal
flat, living individuals burrow 1.5 times theirshell length. In contrast, they burrow shallower(0.7 times) in muddy sand of Matsukawaura
tidal flat (study area 1), and deeper (2.6 times)in gravelly sand of Aburatsubo Cove (study area
4). These observations suggest that living animalsof this species are apt to inhabit in deeper sediment as the substratum becomes coarser. However, it is not confirmed whether this rule can beapplied to other bivalves.
Pratt and Campbell (1956) showed that living
individuals of Mercenaria mercenaria are foundmore deeply in clean sand than those in muddy
sediments. Stanley (1970, 1972) also provided
an example of environmental variation in burrowing depth and life orientation of the same
species. According to his observation, animals
normally live in compact sand with the longaxis of the shell oriented approximately 45 degrees to the vertical, whereas those in muddy
substrata tend to live with their long axis nearlyvertical.
Variations due to other causes: The intraspecific variation due to other causes is sometimes very large: e.g. burrowing depth of R.
philippinarum of equal shell size (3-4 cm) range
from 0.2 to 4.0 cm within one locality in Matsukawaura Inlet (study area 1). It is not apparent
whether this variation stems from truly individual variation or from some other unknown causes.
In this paper, this type of variation is tentatively
included into individual variation.
Interspecific variation - Burrowing depth
and life habit in Bivalvia
As is mentioned earlier, the difference in burrowing depth is compared conveniently by the
relative depth - how many times its shell length
they can burrow at the maximum. The values
range from 0 (most non-siphonate species) to 5.0(Dosinorbis japoniclls of less than 2 cm long).
Absolute values of burrowing depth are, however, more meaningful in considering adaptation
to physical environment. Figure 3 summarizes

absolute depth distribution of bivalves observedin this study. The graph shows that the depth
distribution is not uniform but is concentrated
into three ranges: 1) semi-infauna (partly exposed) and shallow burrowers less than 1 cm
deep, 2) intermediate burrowers less than 15 cm
deep, and 3) deep burrowers less than 30 or 40
cm deep. The most pronounced difference isseen between deep burrowers and other shallower burrowers.
Adult individuals of deep burrowers like
Panopea japonica and Mya arellaria, are permanent burrowers, being unable to reburrow whendisintered. Deep burrowing habit guarantees
them not to be exposed to severe environmental
condition, such as sediment reworking in severe
storms for P. japonica of Kondo (1987MS) or
high temperature for M. arenaria of Goshima(1982). On the other hand, most of the shallow
burrowing bivalves buried less than 15 cm (mostly
less than 10 cm) are active burrowers. They cansurvive, even if they are exposed on the surface
during severe storms, for instance. In short, bivalves inhabiting in shallow water sand bottom
are either active shallow burrowers or immobile
deep burrowers. These are considered to be twobasic adaptive strategies in shallow sandy bottom.
[t is interesting to note that the average levelof sediment reworking in shallow water sandy
bottom is estimated to 15-20 cm, that is, depths
between positions of shallow burrowers anddeep burrowers (Kondo, 1987 MS). Adaptive
divergence of infaunal bivalves in shallow watersand bottom into active shallow burrowers lessthan 15 cm depth and immobile deep burrowers
more than 30 cm depth may be attributed torepeated sediment reworking of about 20 cm
depth.
Amount of individual variation within a species also appears to vary among different life
habit groups. Burrowing depths of most active
burrowers are highly variable. Particularly, largesized individuals are extremely variable: burrowing depth of R. phifippillar1l1l1 of 3-4 cm longranges from 0.3 to 6.0 cm (Figure 2). for instance. [n contrast, burrowing depth ofillllllobile847. Burrowing depth of in fauna l bivalves3110.........
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Depth di str ibution of infauna l bivalves observed in thi s stud y. Numb er of individuals observed
is shown in parentheses.

deep burrowers is much less variable, as shownby Mya arenaria (fig. 14, Gosh ima, 1982). They
appear to burrow to the ir maximum depth. Thismay be explained as foll ows : deepest bu rial isnecessary for them to avoid reworking, because
they can no longer live if they are reworked on
the sea floor.
Burrowing depths of siphonate deposit feed ers, such as Macoma con tabulata and Nuttalliao1il)aCea seem to fall into somewhere between
permanent and active burrowers. They also tend
to burrow as deeply as they can.
Taphonomic impli cation of th e results
The above results are directly applicab le totaphonomic and pa leoeco logic analysis of Rece nt

bivalve species yie lded from the younger deposits. We have now at hand two kinds of data toreconstruct post -mortem disturbance operated in
the different levels of sea bottom. One is shownby obse rvation of differential preservation of life
position among various-sized individuals of asingle species. Particularly , a measure shown by
extremely deep burrowers like P. japonica and
M. arenaria is useful owing to the wide range ofburrowing depth and little variation in burrowing depth of the same shell sizes. The othe r isshown by obse rvation of differential preservation alllong species of different burrowing depth.
Deta iled obse rvation of fossiliferous strata using
both measures wi ll revea l realistic post-mortem
processes (Kondo , 1987 MS).
When we deal with extinct bivalves or living

Yasuo KONDO

312

species of which burrowing depths are unknown,
the above measure can no longer be used and wemust seek another clue to reconstruct burrowing
depth from preservable shell morphology. Next
section thus concerns with relationship between
burrowing depth and shell morphology in Bivalvia.

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Pallial sinus length: an indicator of
burrowing depth
On the basis of the extensive ecologic observations of the Western Atlantic bivalves, Stanley(I970) discussed the relation between the burrowing depth and shell morphology. He emphasized the shell thickness and ornamentation as
closely related characters with burrowing depth.
As shown in his graph (fig. 30, Stanley, 1970),
all thick-shelled burrowing bivalves are restricted
to shallow burrowers. However, all thin-shelledburrowers are not necessarily deep burrowers.
Similarly, all strongly ornamented bivalves areshallow burrowers, while weakly ornamented
bivalves are not always deep burrowers (fig. 32,
Stanley, 1970). These relationships between theburrowing depth and shell morphology are significant in functional morphological point ofview, but they are not applicable to infer theburrowing depth from shell morphology. Moredirectly related character to burrowing depth
should be sought.
The burrowing depth of bivalves can be regarded as length of the siphon at its maximum
extension in many cases. Pallial sinus seen on
the inner surface of siphonate bivalves represents
accommodation space of contracted siphon, andhas long been regarded as an approximate measure of burrowing depth. In this study, I reevaluate the pallial sinus length as a measure of burrowing depth based on my own data on Japanese
species, and also those of Stanley's work (I 970).
Measurements of pallial sinus length
Measurement of the pallial sinus of siphonate
bivalves was made directly with calliper asshown in Figure 4. Pallial sinus length is defined~L.----?I~--L--~

Figure 4. Measurement of pallial sinus length.
Measured part' is shown for the right valve of representative species. S: pallial sinus length, L: shell length, a:
Ruditapes philippillarum (active burrowing suspension
feeder), b: Sillollovacula cOllstricta (probable burrow
dweller), c: Macoma illcollgrua (deposit feeder), d:
Fulvia mutica (active burrowing suspension feeder without pallial sinus).

as a distance from the innermost part of the sinus
to posterior shell margin, so as to represent thelength of contracted siphon. Some bivalves suchas cardiids and some venerids do not show pallial
sinus, but they do have siphons. It is not appropriate to adopt pallial sinus length itself to represent contracted siphon length. Pallial Sinus Index(PSI) is thus defined here as ratio of the lengthfrom the innermost part of the sinus to the posterior shell margin, to shell length.
Table 2 summarizes measurements of PSI for
38 siphonate bivalves, together with their maximum relative burrowing depth. Intraspecificvariation in PSI does not exceed 0.1 in the species examined, except for Panopea japonica,
Mercenaria mercenaria and Ruditapes philippinarum. Panopea japonica show exceptionallyvariable PSI. The variation is due partly to onto-'
genetic decrease, but variation within the individuals of the same shell size is also larger thanother species.
Ontogenetic decrease of PSI is seen in otherspecies such as Dosinorbis japonicus and Tresus
keenae (Kuroda et Habe). Only R. philippinarum
shows ontogenetic increase of PSI.

313

847. Burrowing depth of infaunal bivalves
Table 2. Measurements of Pallial Sinus Index for 38 siphonate bivalves.

Species Name
Nemocardium samarangae (Makiyama)
Chione canacellata (L.)
granulata (Gmelin)C.
paphia (L.)
C.
Mercenaria mereenaria (L.)
Ruditapes pliilippinanlm (Adams et Reeve)
Circe scripta (L.)
Meretrix petechialis (Lamarck)
Cyclina sinensis (Gmelin)
10. Cye/inella tenuis (Recluz)
11. Dosinorbis japonicus (Reeve)
12. Dosinia elegans (Conrad)
13. Antigona Iisteri (Gray)
14. Mactra fragilis Gmelin
veneriformis Reeve
15. M.
chinensis Philippi
16. M.
17. Rangia cuneata Gray
18. Spisula solidissima (Dillwyn)
19. Raeta rostralis (Reeve)
20. Panopea japonica A. Adams
21. Mya arenaria (L.)
22. Barnea dilatata Yokoyama
23. Laternula Iimicola (Reeve)
24. Sinonovacula constricta (Lamarck)
25. Solen strietus Gould
26. Nuttallia oUvaeea (Jay)
27. Donax variabilis Say
dentieulatus L.
28. D.
29. Tel/ina simiUs Sowerby
radiata L.
30. T.
Iisteri R6ding
31. T.
alternata Say
32. T.
33. Macoma eontabulata (Deshayes)ineongrua (v. Martens)
34. M.
balthiea (L.)
35. M.
36. Areopagia fausta (Pulteney)
37. Semele profieus (Pulteney)
38. Strigilla earnaria (L.)

1.
2.
3.
4.
5.
6.
7.
8.
9.

Pallial Sinus Index(No. of measurement)(source)0.149-0.226
0.284-0.312
0.348-0.358
0.312-0.335
0.339-0.478
0.431-0.552
0.218-0.235
0.320-0.337
0.513-0.553
0.458 (1 )(b)0.595-0.674
0.469-0.552
0.455-0.471
0.481-0.515
0.357-0.451
0.388-0.391
0.283 (1) (I)0.317 -0.347
0.326-0.368
0.323-0.520
0.585-0.607
0.247-0.341
0.519
0.382-0.413
0.257-0.317
0.689-0.702
0.518-0.559
0.483
0.805 -0.835
0.754-0.782
0.711-0.728
0.788-0.811
0.705-0.749
0.866-0.909
0.733 -0.823
0.625-0.673
0.600-0.622
0.788-0.847

(3)
(2)
(1)
(1)
(8)
(16)
(3)
(4 )
(4 )
(18)
(5)
(1)
(3)
(7)
(7)
(2)
(4)
(16)
(6 )
(3 )
(1)

(5)
(6 )
(5)
(2)
(1)
(2)
(4)
( 1)
(5)
(5)
(6 )
(6)
(2)
(1)
(2)

Relative maximum
burrowing depth(source)
0.2
0-0.1
0.1
0-0.1
0.7
2.6
0
0.1
1.3, 1.8
1.5
5.0
1.3
1.3
0.5
1.0
0.4
0.5
0.1
1.5
43.0
3
1.5
2.4
2.5
3.9
0.2
0.5
1.6-1.7
0.4-0.5
0.4-0.5
1.3
2.8
2.2-2.3
8.0
3
1.4-1.5
7

(a)
(b)
(b)
(b)
(c)
(a)
(a)
(a)
(a)
(b)
(a)
(b)
(b)
(b)
(a)
(a)
(b)
(b)
(a)
(a)
(d)
(a)

(a)
(e)
(a)
(a)
(b)
(b)

(b)
(b).
(b)
(b)
(a)
(a)
(b)

(b)
(b)
(b)

Sources: a, this study; b, Stanley, 1970; c, Stanley, 1972; d, Goshima, 1982; c, Sugano, 1981; f, Cox, etal.,
1969, Fig. E94, 2b.

Utility and limitation of Pallial Sinus Index
as a measure of maximum burrowing
depth of bivalves
Figure 5 shows the relationship between the

PSI and the maximum relative burrowing depth.
Three life habit groups, namely, deposit feeders,

active burrowers and immobile deep burrowers,
apparently occupy the different region on thegraph. This strongly suggests different functionof their siphons. Maximum burrowing depth inactive burrowing siphonate suspension feeder
represented by venerids and mactrids increase
as PSI becomes large. This "sinus-depth relation"

314

YasuoKONDO
1.0-y---------------------,MOSTLYDEPOSIT
FEEDERLEGEND

Tellinacea•

deposit-feeder

0- suspension- feeder
o feeding habit uncertain
mactridae, veneridae& cardiidae
active burrowing
O suspension-feederVother taxa
immobile deep burrower& burrow dweller

O~----~--_r----~--~----~Ir---~----~--~~o
SL(L:SHELL LENGTH)
MAXIMUM RELATIVE BURROWING DEPTH
Figure 5. Relation between maximum relative burrowing depth and Pallial Sinus Index. Different life
habit groups appear in different region of the graph. In active burrowing suspension-feeders represented byvenerids and mactrids, maximum relative burrowing depth increases rapidly as the increase of the Pallial Sinus
Index. Numbers in the figure represent species shown in Table 2. Two plots of No. 34 (Macoma incongrua)
shows different measurements for right and left valves.

seems natural, because larger sinus is needed toaccommodate longer siphon.
Lower right region of the graph is occupied
by immobile deep burrowers like Panopea japonica and Barnea dilatata. They have pallial sinus
shorter than those expected form their burrowing depth. This is reasonable because the immobile deep burrowers cannot withdraw theirsiphons and they do not need the accommodation space within the shell. Burrow dwellers(Savazzi, 1986) like Solen strictlls and Sillonovaclila constricta also tends to lie lower rightregion. This may be explained by the fact thatthe siphon length do not necessarily show theburrowing depth: They can escape into the deep
permanent burrows which are longer than thesiphon length.
Siphonate deposit feeders represented by Tellinidae appear in the upper region of the graph.
This means that they have deeper pallial sinus
than suspension-feeders of the same burrowing
depth do. This is also reasonable because theirsiphons are feeding organs projecting well on thesediment surface to feed on surface deposits(Young, 1949; Holme, 1961 ; Stanley, 1970).
In summary, PSI of only active burrowing
suspension feeders can be used as a key morphology. The empirical relationship shown in847. Burrowing depth of infaunal bivalves
Figure 5 may allow prediction of maximum
relative burrowing depth of living bivalves ofwhich burrowing depth is unknown. If we assume that the relationship was applicable in thegeologic past, it can also be used in extinct bivalves.
As is obvious in Figure 5, it is almost impossible to infer maximum burrowing depth of deposit feeding bivalves from the PSI. Immobile
deep burrower and burrow dweller are also difficult to infer the burrowing depth. In summary,
PSI is practically useful in siphonate suspension
feeding bivalves represented by venerids. We
cannot, of course, reconstruct the burrowing
depth of non-siphonate bivalves such as lucinaceans. Shell thickness and shell ornamentation
are not very useful index, either. At the present
knowledge, there is no useful character in shellmorphology to infer the burrowing depth ofthese bivalves.
Another line of approaches concerns with
outcrop observation. For example, in the casethat fossil bivalves are buried in situ in the sediment, in which any exotic materials such as thinfine tuff or scoria bed is intercalated, we may
directly know the probable burrowing depth of
the bivalve by recognizing the distance of thelowest presence of the tuff or scoria. Burrowing
depth of fossil Panopea japonica is at least 50
cm (Figure 6), as estimated in this manner in the
Late Pleistocene Shimosa Group, Chiba Prefecture, Japan. This method appears to be mostreliable, although its application is rather restricted. It is also important to test its validityof "sinus-depth relation" by such field observations.
Conclusions(1) In most infaunal bivalves, maximum burrowing depth increases as they grow in a proportional manner. It is then convenient to express
maximum burrowing depth of each species as arelative value - the ratio of maximum burrowing depth to the shell length. The above proportional relationship is, however, unclear in larger
individuals. Relative burrowing depth of larger

315

Panopea burrow

Figure 6. Possible Panopea burrow observed in
the Late Pleistocen Jizodo Formation, at Okura, Ichihara City, Chiba Prefecture, Central Japan. Fine scoria
sand numbered as J10 (Tokuhashi and Endo, 1984)
and black mud are intercalated in the poorly-bedded
bioturbated very fine sand. Large burrows observed
were formed before and after the deposition of theintercalation. No fossils was found in the burrow.
However, Pallopea japonica valves were found in a burrow ill situ similar to these in size and shape in anotheroutcrop.

individuals of many species are generally shallower than those of smaller ones.
(2) Interspecific difference in burrowing
depth among in faunal bivalves reflects well different life habit of each species. Difference between shallow active burrowers and immobile
deep burrowers is especially large. In shallow
subtidal sandy bottom, burrowing depths ofmost bivalves capable of active movement areless than 15 cm. Greater burrowing depth (morethan 30 cm) is attained only by immobile burrowers like Panopea japonica. This may be significant in considering adaptive strategy andevolution of infaunal bivalves: In shallow subtidal sandy bottom, average levels of sediment
reworking is 15~20 cm, and repeated sediment
reworking resulted in divergence into active,
shallow burrowers and immobile deep burrowers.
(3) Ratio of pallial sinus length to shelllength (Pallial Sinus Index: PSI), is useful in inferring the maximum relative burrowing depthof active burrowing, suspension-feeding siphonate bivalves including extinct species. Reconstruction of burrowing depth is, however, difficult owing to the "allometric shallowing" of bur-

Yasllo KONDO

316

rowing depth. We cannot infer burrowing depthof deposit-feeding siphonate bivalves from the
PSI. Field observation of in-situ bivalve fossil
remains may be more reliable to infer the actual
burrowing depth.
Appendix
Description of life position ofsome common Japanese infaunal bivalves
Notes on physiography and molluscan communities of the study areas(1) Matsukawaura Inlet, Some City, Fukushima
Prefecture
Matsukawaura is a small inlet of about 4 km
in N-S trend, situated on the Pacific side ofnorthern Honshu. It is shallow in water depth,closed with a sand bar running south to north,and connected to the Pacific through 120 m wide
opening at its northeastern end. A sand flat in
the northern part of the inlet has been famousfor clamming. Systematic survey of the molluscan fauna within the inlet was made by Kotaka
et al. (1955). My observation was carreid out at
an intertidal muddy sand flat in the northwestof the inlet, near a small sand spit projecting
toward the center of the inlet. At the locality
occurs a dense population of bivalves, such as
Ruditapes philippinarum, Cyclina sinensis, Nuttallia olivacea, Macoma contabulata and Laternula limicola (Reeve). Banks of Crassostrea gigas(Thunberg) also occur patchily on the nearby
soft muddy bottom (fig. 7-2, Chinzei, 1982).
(2) Obitsugawa River delta, Kisarazu City,
Chiba Prefecture
An arcuate delta of the Obitsugawa River isdeveloped on the eastern coast of Tokyo Bay.
An intertidal sand flat of 2 km wide spreads on
the seaward of the delta coast, fringing thearcuate coastline. The geomorphic and otherenvironmental settings of this tidal faIt were described by Kosugi (1986). Mactra veneriformis
and locally Umbonium moniliferum (Lamarck)
are abundant on the middle tidal flat where
Zostera nana is densely distributed. Extremely
abundant individuals of Ruditapes philippinarum

are due to an artificial scattering for a commercial purpose. A lower tidal flat is inhabited by
Dosinorbis japonicus and Solen strictus. Subtidal
zone is characterized by a dense population of
Mactra chinensis with association of Fulvia
l1lutica (Reeve) and Clinocardilll71 buellowi(Rolle).
(3) Aburatsubo area, Miura City, Kanagawa
Prefecture
Aburatsubo is a small inlet with a width of
100-200 m and a length about 500 m. Near themouth of the inlet lies Misaki Marine Biological
Station of the Unviersity of Tokyo. An intertidal
gravelly sand flat near the station is inhabited by
Ruditapes philippinarum, Dosinorbis japonictls
and more rarely Saxidomus purpuratus (Sowerby)and Heteromacoma irus (Hanley). The flat iscovered by mats of Musculus senhausia (Benson).
Only dead shells of Mya arenaria were found inlife position in the gravelly sand. Small-sized
and thin-shelled species as Raeta rostralis (Reeve)and Theora lubrica Gould are living in the subtidal mud of the inlet.
Oblimopa japonica A. Adams, Glycymeris
rotunda Dunker, Venus foveolata Sowerby,
Nemocardium samarangae (Makiyama), andCuspidaria macrorhynchus Smith are common
in sandy mud of about 100 m deep, 2 km northwest off Aburatsubo in Sagami Bay (Horikoshi,1957). They were dredged by R/V Rinkai-Maruof the Misaki Marine Biological Station andobserved in the laboratory.
(4) Off Osezaki, Suruga Bay, Shizuoka Prefecture
A large population of Limopsis tajimae
Sowerby is distributed in the northeastern partof Suruga Bay, off Osezaki (Horikoshi andTanaka, 1980; Horikoshi et aI., 1983; Kondo,1986). Sampling station is 200-300 m in deep,
and the bottom substrate consists of soft mud.
A molluscan fauna at this station is characterized by high species diversity; major constituentsare Limopsis tajimae, Yoldia similis Kuroda etHabe, Acila divaricata Adams et Reeve, Crenulilimopsis oblonga A. Adams, Modiolus margaritaceus (Nomura et Hatai), Machaeroplax myssona(Dall), and Antalis rhabdotum (Pilsbry). A box

847. Burrowing depth of infaunal bivalvescore sampler was used to observe life positionof Limopsis tajimae in KT -86-1 cruise of R/V
Tansei-Maru of the University of Tokyo.
(5) Tsuyazaki area, Fukuoka City, Fukuoka
Prefecture
A small inlet, named Irie, is situated in thenorthwest of Tsuyazaki. The inlet, about 2 km in
maximum length, extends from north to south,
and opens to the Genkainada Sea through anarrow channel. The environmental settings ofthis tidal flat was described by Shimoyama(J 984). Dominant bivalves at an intertidal
muddy sand flat in the inner part of the inlet, areSolen strictus, Macoma incongrua (v. Martens),
Cyclina sinensis and Ruditapes philippinarum.
Distribution of Circe scripta (L.) are restricted
to intertidal pebbly sand of the inlet mouth.
(6) Nata, Fukuoka Prefecture
A long sand bar is developed in the north of
Fukuoka City, by which Hakata Bay is separated
from the Genkainada Sea. Nata beach is situatedon the north side of the sand bar facing Genkainada Sea. A single individual of Gomphina
veneriformis melanaegis Romer and numerous
Chion kiusiuensis (Pilsbry) were collected in theintertidal sandy beach.
(7) Shioya, Kumamoto Prefecture
Shioya is located in the southeastern part of
Ariake Bay. Tegillarca granosa L. is commonly
found on an intertidal mud flat (Iwasaki, 1983),
associated with Cyclina sinensis and Arcopagia
diaphana (Deshayes).
Tegillarca granosa is rather rare in June, 1986,
though it was found abundantly until several
years ago (Y. Iwasaki, personal communication).
This may be caused by environmental changes
due to artificial deposition of a large amount of
exotic sand in the offshore area of this mud flat.
Description of life position andother ecological attributes

Tegillarca granosa (L.)
About ten individuals were observed on theintertidal mud flat at Shioya, Kumamoto City,
Kumamoto Prefecture.

317

Like other infaunal arcids (Stanley, 1970),
this species lives with its posterior flat surface
being horizontal, just above the sediment surface.
The commissure plane may incline on both sides,
though the deviation from the vertical is small.
The posterior flat surface, exposing when alive,
is commonly encrusted by barnacles.

Glycymeris rotunda (Dunker)
Four individuals were collected from the
sandy mud of about 100 m deep, off Aburatsubo. In the eastern part of Sagami Bay, thisspecies occur commonly in muddy substrata,
but is rare in shelly coarse sand bottom. The
preference of muddy substrata seems to deviate
from the general preference of rigorous environment of this genus (Thomas, 1975).
Four individuals were laid on the native sediment in the laboratory tank overnight. The smallest individual attained vertical, posterior-up life
orientation, with the posterior margin just beneath the sediment surface. Middle-sized one
burrowed completely within the sediment at
5-10 mm below the sediment surface, with thecommissure plane oblique. Remaining two large
individuals did not burrow during the observation. This result is not adequate to draw a definite conclusion on life position of this species,
but it does not differ very much from the life
habit described by Stanely (1970) for a congeneric species, Glycymeris pectinata (Gmelin).

Limopsis tajimae Sowerby
This species is common in mud bottom ofupper bathyal zone in the Western Pacific underinfluence of Kuroshio warm current. [t occurs
very abundantly in the northeastern part of
Suruga Bay, off Osezaki, 200-300 m deep (Station B, Horikoshi and Tanaka, 1980). Life habitof this species was observed by means of a box
core sampler at the station in February, 1986.
The substratum sampled together with abundant
living specimens is soapy, fine-grained mud.
This species has a horizontal life p,osition;
lying on one valve, indifferently right or left,

YasuoKONDO

318

just beneath the sediment surface. The commissure plane is roughly horizontal, though there
are some individuals showing variable orientation. This life position is similar to that of an
Atlantic species, Limopsis aurita (Brocchi) reported by Oliver and Allen (1980) and Oliver(1981). Some individuals were observed to burrow a few centimeter form the surface. The
horizontal life position is well reflected to the
distribution of epibionts attached on the shells,such as small mytilid Modiolus margaritaceus;
wide range of distribution on either side of theshells shows horizontal, very shallow or exposed
life position.

Several individuals were collected frommuddy sand of about 100 m deep, off Aburatsubo. Life position of this species was observed
within their native sediment in the laboratory.
Burrowing behavior and life position observed
were consistent with those of cardiids describedby Stanley (1970). Living animals quickly burrow and reach the life position in several rocking movements. Slightly forward rotation fromthe erect probing orientation is needed to attainlife position. The siphon is short and an individual of 3 cm long burrowed only 0.5 cm.

Oblimopa japonica (A. Adams)

Circe scripta (L.)

More than ten individuals were dredged frommuddy sand bottom of about 100 m deep, off
Aburatsubo. Six individuals were laid, with theirright valve down, on their native sediment in thetank, and were left overnight. They crawled on
the sediment surface, leaving sinuous traces. Allof them were oriented vertical to slightly obliqueto the sediment surface, with at least half of
their shells being exposed. This orientation corresponds to 'erect probing orientation' (Stanley,1970) of most burrowing bivalves: orientation
with the ligament axis roughly horizontal. Mostof the individuals examined secreted byssus of 1
to 2 cm long, attaching to coarse sand grains.
This life position differs greatly from that ofLimopsis tajimae of the same family.

About ten individuals were collected from the.
gravelly sand in the intertidal zone near themouth of Tsuyazaki inlet, Fukuoka Prefecture.
The substratum is partly grass-covered pebbly
sand. Living animals were found completely
exposed, on one valve in nature. In the laboratory tank, six individuals were permitted toburrow in exotic fine sand with their right valve
down overnight. They attained an oblique orientation, with their anterior half buried in the sediment. The upward valves are either right or left.
The posterior area of every specimen observed
was attached with calcareous algae, and this suggests normal life position of this species isoblique, with their anterior half in the sediment
as observed in the laboratory. In the Veneracea
this species may be one of the rare examples
which show non-vertical life orientation.

Crenulilimopsis oblonga (A. Adams)
A large number of individuals were collectedwith beam trawl from mud of 200-300 m deepat the northeastern part of Suruga Bay, off
Osezaki. Several individuals were permitted toburrow in their native sediment. Only one individual attained life position, which was vertical,
posterior-up orientation, with the posterior
margin above the sediment surface. The rocking
movement was very slow, once in every 30 to 60
seconds.

Nemocardium samarangae (Makiyama)

Meretrix petechialis (Lamarck)
This species is distributed in the coastal areasof Korea and China (Okutani and Habe, 1975).
Several individuals were purchased at a fish
market in Aburatsubo. In the laboratory, they
were released on very fme sand, which is similar
to their probable native sediment. Living animals
show a vertical life orientation, with their longaxis nearly vertical to the sediment surface.
An individual of 6 cm long could burrow at a
depth of about 1 cm.

847. Burrowing depth of infaunal bivalves

319

Dosinorbis japonicus

Gomphina veneriformis nelanaegis (Romer)
A single individual was collected from intertidal zone of sandy beach of the Genkainada sea,Nata, Fukuoka Prefecture. Ufe position wasobserved in their native clean sand in the laboratory: The commissure plane is vertical, withthe long axis nearly vertical. Burrowing depth
is several millimeters. The posterior portion is
attached by green algae, showing nearly exposed
condition in life.

S.LENGTH (L) (em)

o
o
,,

5
...L

,,
,,
,,

.

.....
.
Ul" .

,,

0

\,

,

\. ~ ~

r-.

5

\0.

0',

()

'-'

Life position of this species was observed
at two localities; the intertidal muddy sand flatof Matsukawaura Inlet, and the intertidal sandy
mud flat of Tsuyazaki Inlet. At both localities,
this species shows a vertical, posterior-up orientation. Maximum burrowing depth of living
animals tends to increase as they grow. The
maximum relative burrowing depth is 1.3 in
Matsukawaura (Figure 7), whereas it is 1.8 inTsuyazaki.

0

'-'

I

••

.. •
. •
~

;

f0...
W

\

\

•

\

,,

••

,,
,

S
a:
a:
:::>
co

°

\

•• • •

,,

\

•
•

\

\

,
,

\

\
\

Cyclina sinensis
SHELL LENGTH (L) (em)

o
'\
r-.

o
'-'
I

~ 2-

W

o

z

S
a:
a:
:::>
co

°4

2

•

,,

(9.
Figure 7. Ontogenetic variation in burrowing
depth of Dosinorbis japonicus observed in Aburatsubo
area (eo) and the Obitsugawa River delta (A), and of
Cyclina sinensis in Matsukawaura Inlet. Black symbols
indicate measurement in nature and open ones in thelaboratory tank.

•

\

Z

15

Ufe position of this species was observed innature on the intertidal sand flat of the Obitsugawa River delta. Laboratory observation was
also made for individuals from the intertidal
gravelly sand of Aburatsubo Cove.
Living animals show a vertical, mostly posterior-up and occasionally beak-up orientation.
Maximum burrowing depth increases as theygrow. In small individuals burrowing depth isabout 5 times as deep as their shell length (Figure7). Young individuals of this species have themaximum value of the relative burrowing depth
among the bivalve species examined in this study.
Large individuals, however, do not burrow so

AI>

\,

10

(9

Dosinorbis japonicus (Reeve)

•

• ••
••

<0<&

.0\,,
r",,
,

r-.

0

••

'

E

Cyclina sinensis (Gmelin)

•

,,

,,
\

,
\

\

,,

,,
\

,
\
\

\

4

•

,

•
•
••
• ••
•
•

.
()\, . . .I.·
...

',!

•• •

~.,

. iii ,•-<\ • •
",

\.

',

\

•

YasuoKONDO

320

deeply in relation to their shell length than
young ones. The maximum burrowing depth in
the specimens examined is 15 cm.

Ruditapes philippinarum (Adams et Reeve)This species is one of the most common
edible bivalves in Japan. A large number of individuals were observed at three localities: intertidal muddy sand flat of Matsukawaura Inlet,
intertidal sand flat of the Obitsugawa River delta,
and intertidal gravelly sand of Aburatsubo Cove.
The substrata in the study area are variable frommuddy sand to gravelly sand.
This species shows a vertical, posterior-up
orientation, with its long axis slightly oblique
from the vertical at every locality. Relative
maximum burrowing depth is variable according
to the substratum type: ranging from 2.6 times
its shell length (gravelly sand of AburatsuboCove) to 0.7 (muddy sand of Matsukawaura)
as shown in Figure 2.
Young individuals smaller than 2 cm long
employ byssus to attach a small pebble or asand grain.
I happened to observe orientation during
escape from burial with sediment. In this situation, all the individuals show anterior-up verticalorientation. This orientation is the same as the"inverted erect probing orientation" of Krantz(1974), and suggests that this species pulls themselves with foot upward during escape form

Mactra veneriformis

burial.

Mactra veneriformis Reeve
Life position of this species was observedon the intertidal sand flat of the Obitsugawa
River delta. This species shows an erect probing
orientation with the posterior flattened surface
nearly horizontal to the sediment surface. Life
orientation is with the long axis nearly vertical.
The maximum relative burrowing depth is 1.0(Figure 8).

Macta chinensis Philippi
Small individuals of this specis were observedin nature on the intertidal sand flats of Ena Bay,near Aburatsubo. Large individuals were dredgedin great abundance from sandy mud of about 10
m deep, off Obitsugawa River delta.
Erect probing orientation is with the posterior
flattened surface horizontal. When this species
attains life position, the long axis of the shell isdirected nearly vertical. The maximum relative
burrowing depth is 0.4 (Figure 8).

Chion kiusiuensis (Pilsbry)
A number of individuals were collected fromthe sandy intertidal zone of Nata beach. Observed life orientation is vertical, with the posterior flat margin horizontal at just beneath thesediment surface. Judging from the extended

Mactra chinensis

,...,

,...,

SHELL LENGTH (L) (em)
0

Eo
,,
0

'-'

......,
0

'-'

I
I0..

w2

0

m

2

,,

,,

,

•

,

. •• •••• •••••-'-,<>~'~< '--

',!t,

• '.
4

',.•
,

•

SHELL LENGTH (L) (em)

E

0
0
2
4
'-'0 ~:----I--...L.----II---O·<DO-c.o-o

,...,
0

'-'

I
I0..
W

'"

" ,

"

o

0

0 0

6
'

0

o

o
o

0

m 2

Figure 8. Ontogenetic variation in burrowing depth of Mactra veneriformis and M. chinensis observed inth Obitsugawa River delta (eo) and Ena Bay (.). Black symbols indicate measurement in nature and open onesin the laboratory tank.

847. Burrowing depth of infaunal bivalves
siphon length of about half of the shell size,
animals can probably burrow at the same depth.

Nuttallia olivacea (Jay)
A large number of individuals were observedin the intertidal muddy sand flat of Matsukawaura Inlet. The life orientation observed is a vertical, posterior-up, with the posterior flat margin
approximately horizontal. The maximum relative
burrowing depth is 3.9 (Figure 9). The siphonof this species is slender and long, being similar
to that of deposit-feeding tellinids. I did not,however, observe deposit-feeding activities of thisspecies.

Macoma contabulata (Deshayes)
A large number of individuals were observedon the intertidal muddy sand flat of Matsukawaura Inlet. The life orientation observed is vertical, posterior-up, with the long axis roughly
vertical. This vertical orientation is rather unusual in tellinids, most of which employ right-

Nuttallia olivacea

Macoma contabulata

s. LENGTH (L) (em)S. LENGTH (L) (em)
0

5

0

0

0

···•
•
··
··
E
·.
.
8
... •....•
n.
f"",....
_'a.z'. ,..
......
u......

\

5

\

\

I
l-

w
0

\

o.

~\..

I

.~',

e:>

~10
0
0:
0:
::J
CD

\

....

.' \

\-

~

5

.-,

··
··

E

\

\

u
......

8I 5

\

\

\

...

\.• '"••

I-

o·
\\\ •

W

<P.

n.

0

CJ
Z

~

010
0:
0:
::J
CD

~\

••

•
...
.... • • •1'"" \ .

·· ...•
. ••

-

\

\

\

\

...

Figure 9. Ontogenetic variation in burrowing
depth of Nuttallia olivacea and Macoma contabulata
observed in nature on the intertidal nat of Matsukawaura Inlet.

321

valve-up, horizontal orientation (Holme, 1961;
Stanley, 1970). However, the nearly equivalve
condition of this species seems to suggest avertical life orientation, as in Macoma balthica(L.) described by Stanley (1970). The maximum
relative burrowing depth is 2.8 (Figure 9).
This species was observed to deposit feed,using the vermiform siphon.

Macoma incongrua (v. Martens)
Only dead specimens of this species wereobserved, although it was formerly abundanton the intertidal sandy mud bottom of Tsuyazaki Inlet. They still preserve their probablenormal life position within the sediment. The"life orientation" observed is roughly horizontal
with their right valve upward. Burrowing depth
is almost constant, and the maximum relative
depth ranges from 2.2 to 2.3.

Solen strictus Gould
Several individuals were observed on theintertidal sand flat of the Obitsugawa River delta.
This species is abundant in the lower part of thesand flat, commonly associated with Dosinorbis
japonicus. Living animals are found in burrows
which is very thinly lined with silt. Owing to thelining, the inner wall of the burrow is smooth.
The burrows are usually oriented 0 to 30 degrees
from the vertical. When observed, most of theindividuals were found in the lowermost part ofthe burrows, although they are supposed to beable to go up and down in the burrows. Maximum length of the burrows are 3.5 times theshell length. Maximum relative burrowing depth
is, therefore, 2.5.

Panopea japonica A. Adams
The specimens observed were purchased ata fish market in Aburatsubo. In an attempt toknow the extended siphon length, the specimen
was buried within the sediment, keeping anassumed life orientation. The maximum extension of the siphon within the sediment is regarded as the burrowing depth of this species.

YasuoKONDO

322

In this way, probable maximum burrowing
depth was measured about 4 times the shelllength. The average adult individuals thus burrow as deep as 40-50 cm.

Cuspidaria macrorhynchus Smith
A few individuals were dredged from the
sandy mud of about 100 m deep, off Aburatsubo. Living animals show a vertical posteriorup life orientation, with the long axis nearlyvertical. The posterior projected part of theshell is exposed above the sediment surface.

Laternula limicola (Reeve)
Several individuals were observed on theintertidal muddy sand flat of Matsukawaura
Inlet. Living animals keep a vertical posteriorup life orientation, with the long axis 15 degrees
inclined from the vertical. The maximum relative
burrowing depth is 1.5.

References
Aigner, T. (1982): Calcareous tempestite: storm-dominated stratification in Upper Muschelkalk Limestone (Middle Trias. SW-Germany). In: Einsele, G.
and Seilacher, A. (eds.), Cyclic and event stratification, Springer-Verlag, 536 p.
Ausich, W. I. and Bottjer, D. J. (1982): Tiering in suspension-feeding communities on soft substrata
throughout the Phanerozoic. Science, 216, 173174.
- - and - - (1985): Phanerozoic tiering in suspension-feeding communities on soft substrata: implications for diversity. In: Valentine, J.W. (cd.),
Phanerozoic diversity pattern: profiles in macroevolution, Princeton University Press, 441 p.
Bloos, G. (1982): Shell beds in the lower Lias of South
Germany - facies and origin. In: Einsele, G. andSeilacher, A. (eds.), Cyclic and event stratification,
Springer Verlag, 536 p.
Chinzei, K. (1982): Paleoecology of oysters (2). Kaseki(Fossils), (32), 19-27 (in Japanese).
Cox, L. R. (1969): Treatise on invertebrate paleontology, Part N, Mollusca 6, Bivalvia. Geol. Soc.
Amer. and Univ. Kansas.
Goshima, S. (1982): Population dynamics of the softclam, Mya arenaria 1.., with special reference to its
life history pattern. Publ. Amakusa Mar. Bioi.

Lab., Kyushu Univ., 6, 119-165.
Holme, N. A. (1961): Notes on the mode of life of the
Tellinidae (Lamellibranchia). Marine BioI. Assoc.
United Kingdom Jour., 41, 699-703.
Horikoshi, M. (1957): Note on the molluscan fauna of
Sagami Bay and its adjacent waters. Sci. Rept.
Yokohama National Univ., Sec. II, (6),37-64.
--and Tanaka, R. (1980): Ecology of a bivalve
species Limopsis tajimae living in the bathyal zoneof Japanese coast. Abs. seasonal meeting (spring),
Oceano I. Soc. Japan, 316-317 (in Japanese).
- - et af. (1983): Preliminary catalogue of benthic
organisms collected at each station during various
cruises of R/Vs Tansei-Maru and Hakuho-Maru,
Ocean Research Institute, University of Tokyo(1966-1982). Ocean Res. Inst. Univ. Tokyo, 160
p.
Iwasaki, Y. (1983): What can be known through the. paleoecological approaches? Kaseki (Fossils), (34),
13-15 (in Japanese).
Kidwell, S. M. and Aigner, T. (1985): Sedimentary
dynamics of complex shell beds: implications for
ecologic and evolutionary patterns. In: Bayer, U.
and Seilacher, A. (cds.), Sedimentary and evolutionary cycles, Springer Verlag, 465 p.
Kondo, Y. (1986): Observation of ecology of Limopsis
tajimae by means of box core sampler. Abs. 135th
regular meeting, Palaeollt. Soc. Japan, 18 (in Japanese).
--(1987MS): Biostratinomy of infaunal bivalves comparative analysis of life position of living andfossil bivalves. Doctoral dissertation, Univ. Tokyo,
102 p.
Kosugi, M. (1986): Transportation and sedimentation
patterns on dead diatoms in a tidal area - a casestudy in the lower reach of the Obitsu River -.
Geogr. Review, Japan, 59, (Ser. A.), 37-50.
Kotaka, T., Kamata, Y. and Hayasaka, S. (1955):
Molluscs in Matsukawaura inlet. Tohoku Univ.,
Inst. Geol. Pal. Contr., (45), 53-63 (in Japanese).
Kranz, P. M. (1974): The anastrophic burial of bivalves
and its paleoecological significance: Jour. Geology,
82,237-265.
Okutani, T. and Habe, T. (1975): Mollusca II, Illustrated encyclopedia for students. Gakken, Tokyo,
294 p. (in Japanese).
Oliver, P. G. (981): The functional morphology andevolution of Recent Limopsidae (Bivalvia, Arcoidea). Malacologia, 21,61-93.
--and Allen, J. A. (1980): The functional andadaptive morphology of the family Limopsidae(Bivalvia: Arcoida) from the Atlantic. Phil. Trans.
Royal Soc. London, Ser. B., 291,77-125.
Pratt, D. M. and Campbell, D. A. (1956): Environmental
factors affecting growth in Venus mercenaria.
Limnology and Oceanography, I, 2-17.

847. Burrowing depth of infaunal bivalves
Savazzi, E. (1986): Burrowing sculptures and life habitsin Paleozoic lingulacean brachiopods. Paleobiology,
12,46-63.
Shimoyama, S. (1984): Size-frequency distributions ofliving population and dead shell assemblages ofMacoma (Macoma)_incongrua (Martens) on anintertidal mud-flat in North Kyushu. Mem. Fac.
Sci. Kyushu Univ., Ser. D., 25,271-187.
--(1985): Size-frequency distribution of living
population and dead shell assemblages in a marine
intertidal snail, Umbonium (Suchium) moniliferum (Lamark), and their paleoecological significance. Palaeogeogr. Palaeoclimatol. Palaeoecol.,49,327-353.
Stanley, S. M. (1968): Post-paleozoic adaptive radiationof infaunal bivalve molluscs - a consequence ofmantle fusion and siphon formation. Jour. Paleont., 42,214-229.
--(1970): Relation of shell form to life habits of theBivalvia (Mollusca). Geol. Soc. America, Mem.,125.
--(1972): Functional morphology and evolution of
byssally attached bivalve molluscs. Jour. Paleonto!., 46, 165-212.
Sugano, T. (1981): The Ariake Sea. Tokai Univ. Press,
194 p. (in Japanese).
Thomas, R. D. K. (1975): Functional morphology,
ecology, and evolutionary conservatism in the
Glycymerididae (Bivalvia). Palaeontology, 18,
217-254.
Tokuhashi, S. and Endo, H. (1984): Geology of theAnesaki District. Quadrangle Series, scale 1 :50,000,
Geo!. Surv. Japan, 136 p. (in Japanese with English
abstract, 6 p.).
Young, C. M. (1949): On the structure and adaptationof the Tellinacea, deposit-feeding Eulamellibranchia. Phil. Trans. Roy. Soc. London, Ser. B.,
234,29-76.

Matsukawaura t~)II1m, Obitsugawa River 'NilV II , Kisarazu *!l!i$, Aburatsubo rm~. Miura =:Osezaki :kifJllff,lj-, Suruga Bay ~i"J~, Tsuyazaki i$~Iff,Ij-, Nata ~~, Hakata
Bay fW:~~, Genkainada Sea :;K$i.L Shioya ~~, Ariake Bay ~lJIliW, Ena Bay iI~~.

1m, Sagami

323

mm,

P'J~=tcfi.~rt!tA~IJl-:m~~~Wl~:}.; J: lfmt~~.!:: ~i*l1* : S*~!t!!~Tl~t.cc'-e22~~
P'J~=tcfi.~a_~~rt!tA~IJl~~.Lk.
=tcfi.~rt!tA~lJlli, liiJ-~-eib"'?-C{" #>-Ij-1;;(',

a_, k~ft!!.~~ftj:~::'J:"'?-cl!tfti"7.J~-e. ib 7.J~~rt!tA~IJl~~!li~::.~:mi" 7.J ::..!:: li-c:'~tJ:~ '. LIJ' L. rt!tA~IJl~J\i:k~~::'l± Eli" 7.J.!::, k.nli#>-Ij-1' ;;('~nI1:;ljH::.~:unt{?UL-cJ:f!l:ki"7.J::.!::i1~7f7J'"'?t.:. Lt,:7J~"'?-C. J\i*rt!tA~1Jl~#>-Ij-1' ;;('~::.Mi"7.J.It~m~'-Ck~~~rt!tAfjg:1J~~:m L -C:}.; <.!::{!!!fU-C:'ib7.J ({?U.:tli, 7-1j-I)
li2.6, :JJ 7i' ~ 7i'1Ii5.0).
rt!tA~IJli1~~'::- .!::~::.it? ~lik.n-t.n~~ii5f*A~it~'~ J: <&~ L -C~'7.Jt.:.lO-eib7.J. %'~::.
~U'~li, 7-1j-I)~J~:JJ7i'1'~J:?~::'. i'li:<rt!t')tJ:iM.) (mL-C15cmJ:I)i'li:H. i9GH:I:l~.n-C{, Mlfrt!t7.Jfjg:1JHIil.:t t.:fifiJ$!.!::. -r ~ ;If l' ~ J: ? ~::~.lO-C~ <m7.J 7J'h I)~::' (30 -40cm J: IJ ~H i9GHl:\ ~.nt.:ib.!:: Mlfrt!t7.J1Jg:1J~t&~ Lt.:~~.!:: ~it~ '-C:'ib"'? -C, ::.nGliil'Jifk~::'$alID..l~::.i9G~ 'I±\~.n 7.J 1it~~i'iii~ 'i'li:$~. %'~::Ii'J;Jj!):::}.;~ '-C P'J~=tc¥l.i1~Jfx I) f~7.J .M.:-?~~ii5f*A-C:'
ib7.J.
ft;p~~rt!tA~!t~~j[:i" 7.J t.:.lO~::'li, ~*.3!~A~~~ (t.:t!. L, *~ilfHift:>riS9E~::.rt!t7.JilI~
1t;jli~::.rll G.n 7.J) i1~, J\i {, ~~-e ib 7.J :: .!:: 7J~5J'7J'",? t.:. LIJ' L, :: ~ J: ? tJ:mt~~~::.~--:> <~j[:~::'li~l1f.7J~ib '), El1=.i't:J£:IX~ft;P~SliJjWl~tJ: c'~jj1L:1~i't:JtJ:illEj~!!,I::'~--:>~ ,t.:~j[: {, ibh-l!t-Crr.il[§J.ijifiE? :: .!:: 7J~~;!: L ~ '.

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 324-334,4 Figs., December 30, 1987

848. CRETACEOUS CAESTOCORBULA (BIVALVIA) FROM JAPAN*
T AKESHI KOZAI
Higashi Primary School, Kochi 782

Abstract Six species of the genus Caestocorbula Vincent, including three new species,
C. antiqua, sp. nov., C. monobensis, sp. nov. and C. ohtai, sp. nov., are described from ten
localities of the Cretaceous in Japan.

Introduction

grained sandstone in the upper part of the Tatsukawa Formation at a roadside exposure, about
800 m south of Hiroyasu, Katsuura-cho, Katsuura-gun, Tokushima Prefecture. Neocomian (Figure I-a).
Loc. 2. Medium to fine-grained sandstone in
the lower member of the Hibihara Formation,at an exposure near a path, about 500 m northof Doiban, Monobe-mura, Kami-gun, Kochi
Prefecture. Lower Aptian (Figure I-C).
Loc.3. Medium-grained sandstone in thelower member of the Hibihara Formation , at an
exposure near a path, about 1 km northwest of
Kaminaro, Monobe-mura, Kami-gun, Kochi Prefecture. Probably Lower Aptian (Figure I-C).

Hayami (in Hayami and Oji, 1980) has newly
introduced two species, C. shikamai Hayami and
C. minima Hayami, in Caestocorbula from the
Choshi district, Chiba Prefecture. Subsequently
Tashiro and Otsuka (I982) established C. obsoleta Tashiro et Otsuka from the Upper Himenoura Subgroup in Amakusa-shimojima Island,
Kyushu. In addition, Kozai (I986) mentionedthat "Pulsidis higoensis (Matsumoto)" is probably referable to Caestocorbula because of its
hinge structure and features of right valve.
In the present article six species including
three new species are described on the basis of
newly collected materials from ten localities
distributed in Kyushu, Shikoku and Kanto(Figure 1). The previously described species from
Choshi and Amakusa are also re-examined byadditional specimens being well preserved anddetail observations.
The specimens described in this paper are
mostly kept in the Geological Collections ofFaculty of Science, Kochi University (KSG),
Kochi and partly in the University Museum, theUniversity of Tokyo (UMUT), Tokyo.

Loc. 4. Medium-grained sandstone in thelower member of the Hibihara Formation at aroadside exposure, about 1 km northwe'st of
Kaminaro, Monobe-mura, Kami-gun, Kochi Prefecture. Probably Lower Aptian (Figure I-C).
Loc. 5. (= Loc. 7 in Tashiro and Otsuka
1980, 1982) Medium-grained sandstone in th:
uppermost formation of the Upper Himenoura
Subgroup, at an exposure near a path, about 350
m north of Masuno, Ushibuka City, Kumamoto
Prefecture. Maastrichtian (Figure I-B) .
. Loc.~. (~ Loc. 20 in Tamura, 1976, 1979)
Fme-gramed sandstone in the lower formationof Mifune Group, at a roadside exposure, about
150 m north of Masunoo, Mifune-cho, Kamimasuki-gun, Kumamoto Prefecture. Cenomanian(Figure I-D-1).

F ossiI localities
Loc. 1. (= Hy.5032 in Hayami, 1966) Fine*Received May 4, 1987; revised manuscript accepted
October 30, 1987; read February 3, 1985 at the
University of Tokyo.
324848. Caestocorbula from Japan

325

0- 1

Tsuzumugllkm

A

YokoseTazukawa

lkm

c

r

I ..... r.")....

\",-=

lkm

N

MI. Konoll.

lkm

Figure 1. Map showing fossillocalitics.
A=Katsuura area, Tokushima Prefecture. B=Amakusa-Shimojima area, Kumamoto Prefecture. C=Monobe area,
Kochi Prefecture. D=Mifune area, Kumamoto Prefecture. E=Choshi district (see Hayami and Oji, 1980). X=
Fossil locality .

Takeshi KOZAI

326

Loc. 7 (~ Loc. 5 in Tamura, 1976, 1979)
Fine-grained sandstone in the lower formationof Mifune Group, at a roadside exposure, about
1 km southeast of Asanoyabu, Mifune-cho,Kamimasuki-gun, Kumamoto Prefecture (Figure
I-D-2).
Loc. 8. (~ Loc. 11 in dittos) Fine-grainedsandstone in the lower formation of Mifune
Group, at a roadside outcrop, about 1.5 km eastof Kawauchida, Mifune-cho, Kamimasuki-gun,
Kumamoto Prefecture. Cenomanian (Figure
I-D-3).
Loc. 9. (~ Loc. 4 in dittos) Fine-grained sandstone in the lower formation of Mifune Group,
exposed on a river side, about 500 m east of
Kitakawauchi,
Yabe-cho,
Kamimasuki-gun,
Kumamoto Prefecture. Cenomanian (Figure
I-D-4).
Loc. 10. (= Loc. 2 in Hayami and Oji, 1980)
Choshi District. See Hayami and Oji, 1980, p.
421, Text-fig. 1.
Systematic description
Family Corbulidae Lamarck, 1818

corbula characterized by elongated area andflattened interior area.
Description:-Shell small, inequivalve, inequilateral, moderately inflated, longer than high;right valve larger than left; test moderately thick;anterior dorsal margin short, slightly curved;
posterior dorsal margin long, nearly straight or
broadly arched; ventral margin gently arched;umbo slightly prosogyrate, situated at about
one-third of shell-length in right valve but about
mid-length in left; area rostrated; surface covered
with fine concentric ribs, which are regularly
spaced, round-topped; interior of right valve
grooved with margin of left valve; interior ofarea flattened; hinge plate narrow; pallial line
indistinctly impressed, not sinuated; adductor
muscle scars clearly impressed, subelliptical;
posterior one larger than anterior; cardinal toothof right valve projected, heavy, rounded; resilial
pit excavated, rounded, located at anterior of
cardinal tooth; cardinal socket large, chondrophore slightly prominent.
Measurements (in mm):Specimens
KSG-K074. R.in.m.

L
S.O

H
4.1
3.1

Subfamily Caestocorbulinae Vokes, 1945

KSG-K07S. L.in.m.
KSG-K076. L.in.m.

Genus Caestocorbula Vincent, 1910

KSG·K077. R.in.m.

S.S
5.6
7.3+

KSG-KOSO. R.in.m.

7.5+Type species:-Corbula henckeliusiana Nyst
Remarks:-Vokes (1945) established Casestocorbulinae, and included the genera Caestocorbula and Pamlicorbula in it. Pamlicorbula
differs from Caestocorbula in having a shallow,
inconspicuous groove on the siphonal plate.
Later Parmicorbula is regarded as a subgenus of
Caestocorbula by Keen (in Cox et al., 1969).
Caestocorbula (s.1.) antiqua, sp. nov.
Figures 4-21-28

Materia/:-Holotype, KSG-K074, internalmould of right valve; Paratypes; KSG-K077,
KSG-K080, KSG-K081 and KSG-K085, internalmoulds of left valves; KSG-K082, external mouldof left valve; KSG-K083, external mould of rightvalve; all the specimens are collected from loco 1.
Diagnosis: -Small-sized species of Caesto-

B

3.5

HIL

U/L

S/L

2.7

2.2

0.51

0.34

0.2S

2.9
2.6

-

0.61
0.55

0.50
0.46

-

0.51

U

3.5

2.1

3.5

KSG-KOSI. R.in.m.

7.0+

3.6
3.2

KSG·KOS2. L.ox.m.

6.S

4.2

1.5

3.5

-

0.61

KSG-KOS3. R.ex.m.

6.9

4.3

2.0

2.5

-

0.62

0.36

-

KSG-KOSS. R.in.m.

6.9

3.5

2.7

I.S

0.51

0.39

0.26

2.1

L.=left valve, R.=right valve, in.m.=internal mould,
ex.m.=external mould, L=length, H=height, B=breadth,
U=distance from beak to anterior end, S=discrepancy
between right valve and left valve.

Remarks:-About 40 specimens were collected from loco I in the Tatsukawa Formation.
This species occurs together with brackish-watermolluscs as; Costocyrena otsukai (Yabe et
Nagao), Hayamina naumanni (Newmayr) andProtocardia ibukii Nakazawa et Murata. Caestocorbulid species have been hitherto only reported from marine deposits. Therefore this is
the first report of the occurrenee from nonmarine deposits. Although the siphonal plate
is not actually ascertained, the present species

848. Caestocorbula from Japanshows a similar hinge structure to that of the
known species of Caestocorbula.
The surface ornamentation in almost all the
specimens is weathered, but several specimens,
e.g. KSG-K082 and KSG-K084, show concentricribs clearly near the ventral margin. Concerntricribs are numbered about 9 in 1 mm. Ratios of
S/L are 0.28 (KSG-K074) and 0.26 (KSG-K085).
These values indirectly support the idea that thisspecies has siphonal plate. Because the siphonal
plate is not determined whether this species isreferred to the subgenus Caestocorbula (Caestocorbula) or C. (parmicorbula).
Comparison: -This new species is similar to
Caestocorbula minima Hayami, 1980, from the
Choshi district, Chiba Prefecture, in having the
sub pyriform outline, but has a more elongatedarea in the left valve than that of the latter. It
is also similar to Caestocorbula (Parmicorbula)neaeroides (Blanckenhorn, 1890) (in Vokes,
1945) from Aptian in the Lebanon Mountains,
Republic of Lebanon, in having fine concentricribs on the surface, but the latter has a moreelongated area than the former.
Occurrence:-Occasionally found at loco 1.
Neocomian.

Caestocorbula (?Parmicorbula) minima Hayami
Figures 4-21-23
1980. Caestocorbula minima Hayami, in Hayami andOji, p. 437-438, pI. 53, figs. 15, 16.

Material:-Holotype, left valve (UMUT MM
9764); Paratypes, left (UMUT MM 9766), right(UMUT MM 9765). These specimens were collected from the Kimigahama Formation in the
Choshi district, Chiba Prefecture by Hayami andOji.
Remarks: - This species was established byHayami (1980) based on 3 conjOined valves anda left valve from the Choshi Group, Chiba Prefecture. The surface ornamentation is well preservedin them, but hinge and other internal characters
are unknown. The siphonal plate is possiblypresent in them, judging from the discrepancy
of both valves. This species has a distinct pos-

327

terior carina in the left valve, but no posteriorcarina in the right.
This species is similar to Caestocorbula(Parmicorbula) striatula (Sowerby, 1827) (inVokes, 1946) from the Lower Greensand in England and Caestocorbula (Parmicorbula) aequilineata (Vokes, 1946) from the Aptian in the
Lebanon Mountains, in fine concentric ribs andelongated area, but latters have distinct posteriorcarina in both valves. However, the Japanese
species have no posterior carina in the right.
Occurrence:-Very rare, at loco 10. Barremian.

Caestocorbula (?Parmicorbula) shikamai Hayami
Figures 4-1-9
1980. Caestocorbula shikamai Hayami, in Hayami andOji, p. 436-437, pI. 53, figs. 8-12.
1986. Caestocorbula sp. cf. C. shikamai Hayami;
Tashiro and Matsuda, p. 385, pI. 1, fig. 31.

Material:-Holotype, right valve (UMUT MM
9735) illustrated by Hayami (1980, pI. 53, fig.
10) was collected from the Ashikajima Formation at Ashikajima, Choshi district, Chiba Prefecture. Additionally, 11 specimens are collectedfrom the Hibihara Formation in Kochi Prefecture (locs. 2, 3) for the following description.
Diagnosis:-Medium-sized species of Caestocorbula characterized by strongly inflated valves
and less rostrated area.
Description:-Shell medium-sized, strongly inflated, subtrigonal, a little longer than high; test
thick, heavy; right valve shortly rostrated, larger
than left; anterior-dorsal margin weakly concave;
ventral margin broadly arched, slightly sinuatednear area; postero-dorsal margin nearly straight;
umbo located at about mid length, slightly
prosogyrate; surface ornamented with concentricribs, which are round-topped, regularly spaced,
denser in posterior half than in anterior; internal
margin of right valve distinctly grooved as a
receptional scar of margin of left valve; innerareal part flat; cardinal tooth of right valve large;
resilial pit large and deep; adductor scars wellmarked in suboval; posterior adductor scarlarger than anterior one; chondrophore subtrigonal.

Takeshi KOZAI

328

Measurements (in mm):Specimens
KSG·KllO. R.in.m.
KSG-K Ill. L.in.m.
KSG·K 112. L.ox.m.
KSG-KIl3. L.in.m.
KSG·KI14. L.in.m.
KSG·KI15. R.in.m.
KSG·K 116. L.in.m.
KSG·K 118. L.in.m.

L

H

5.9
5.6
8.1
7.5
6.9
7.9
6.7
7.4

~.I

3.7
5.8
5.9
4.4

5.3
5.1
5.6

B

2.8

U
3.3
3.3
5.0
U
3.5
3.6
~.O

4.1

0.5

0.7

H/L

lI/L

S/L

0.65
0.66
0.72
0.89
0.65
0.67
0.76
0.71

0.56
0.59
0.62
0.64
0.51
0,46

0.08

0.59
0.55

-

-

0.09

Remarks:-This species was described byHayami (in Hayami and Oji, 1980) based on 11
sepcimens from Choshi Group, Chiba Prefecture.
As these specimens are preserved well, the external and internal features are well recognized.
The specimens from Choshi were at first treatedas Pulsidis higoensis (Matsumoto) by Shikama
and Suzuki (1972), but Hayami (in Hayami andOji, 1980) established Caestocorbula shikamai
for them.
The specimens from the lower part of the
Hibihara Formation are smaller than the typespecimen, but are safely identified with C. shikamai in their diagnostic features, such as strongly
inflated and less rostrated valve. The value of
0.08 or 0.09 in S/L is the smallest one among
the species of this genus from Japan.
This species was also described from the
Sakawa area, Kochi Prefecture by Tashiro andMatsuda, 1986.
Occurrence:-Occasionally found at loco 10.
Rare at loco 2 and common at loco 3. Aptian.
Caestocorbula (?Parmicorbula) monobensis,
sp. nov.

Diagnosis:-Medium-sized species of Caestocorbula characterized by absence of carina in
the left valve and the disk hollowed on the posterior part.
Description: -Shell inequilateral, moderately
inflated, longer than high; right valve larger,
more inflated and more rostrated than left one;test comparatively thick; anterior dorsal margin
nearly straight or gently concave; ventral margin
broadly arched; posterior dorsal margin sharply
curved in rear of umbo, longer than anterior
dorsal margin; anterior margin nearly semicircular: ventral margin gently arched; umbo ofright valve small prosogyrate, moderately prominented, situated at about mid-length of the shell;umbo of left valve somewhat prominent, situatedat some distance in front of the mid-length; surface covered with regular fine concentric ribs,
which are round-topped, regularly spaced, anddencer on the umbonal part of disk than on theventral part; disk hollowed on posterior part;internal margin of right valve grooved as a
receptional scar of margin of left valve; suporting buttress presented; internal area faintly or
shallowly grooved; hinge plate narrow, long
grooved on lateral part; pallial line indistinctly
impressed; posterior adductor scar elliptical,
moderately impressed, larger than anterior one;cardinal tooth of right valve triangular, heavy,round-topped; resilial pit triangular, deeply excavated; cardinal socket large, deeply excavated;chondrophore triangUlar, and thin.
Measurements (in mm):Specimens

Figures 3-1-·11
1986. Caestocorbula minima Hayami; Tashiro andMatsuda, p. 384-385, pI. 77, figs. 27-30.

Material:-Holotype, KSG-K063, internalmould of right valve; 11 paratypes, KSG-K064 KSG-K067 and KSG-K062, internal moulds ofright valves; KSG-K068, KSG-K072 and KSGK073, external moulds of right valves; KSGK069 and KSG-K070, internal moulds of left
valves; KSG-K071 ,external mould of left valve.
These specimens were collected from loco 4.

KSG-K063. R.in.m.
KSG·K062. R.in.m.
KSG·K064. R.in.m.
KSG-K065. R.in.m.
KSG-K066. R.in.m.
KSG-K067. R.in.m.
KSG·K068. R.eK.m.
KSG·K069. L.in.m.
KSG·K070. L.in.m.
KSG-K071. R.eK.m.
KSG-K072. R.eK.m.
KSG·K073. R.cK.m.

L
H
11.4
7.5
13.1+ 8.1
13.2 10.1
10.0
7.5
12.0
8.5
10.5
7.4
6.6+
11.7
12.2
7.8
6.0+
11.4
8.5
12.8
12.5+ 8.1
11.2
8.0

B

2.8

2.7
3.3
2.8

U
6.1
8.1
7.0
4.0
5.3

6.1
7.0
6.4
8.1
6.0
6.4

5
1.4
1.5
1.5
1.2
1.5
1.5

HIL
0.66

U/L
0.54

0.77
0.75
0.71
0.70

0.53
0.40
0.44

-

0.66

0.52
0.57
0.57
0.63

0.71

0.51

0.64

S/L
0.11
0.12
0.10
0.12
0.14

Observation:-About 30 specimens were collected from the lower part of the Hibihara For-

848. Caestocorbliia from Japanmation. Almost all of them show smooth surface,
but this is certainly due to predepositional abrasion. A few specimens (i.e. KSG-K072 and KSGK037) have clear concentric ribs. Right valves
are much more numerous than the left ones. The
ratio H/L is 0.71 on an average in the right valve
and 0.64 in the left valve. Ratio of U/L is 0.51
on an average in the right valve and 0.S7 in theleft. An average of U/L is 0.12. This consequenceis related to existence of siphonal plate. The
siphonal plate has not been recognized yet, but
it may have been existent in this species, because
the interior of right valve is grooved for the
reception of the left valve margin.
Comparison: - This species is similar to somespecies of C. (Parmicorbula) in the surface ornamentation, but it is difficult to decide whether it
belongs to C. (Caestocorbllla) or C. (Parmicorbula). This new species is somewhat similar
to Caestocorbliia shikamai Hayami in the inflated
valve, but is distinguished from the latter by its
more rostra ted area. In this respect, it is similar
to Caestocorbula minima Hayami, but it differsfrom the latter in more elongated area. As tothe external characters, the present species issimilar to Caestocorbula (Parmicorbllla) sinnosa(Stephenson, 1941), from the Woodbine Formation of Texas and Caestocorbula (Parmicorbula)neaeroides (Blanckenhorn, 1890) (in Vokes,
1945), from the Aptian of the Lebanon Mountains, Republic of Lebanon, but this species isdistinguished from the latters by more prominentumbo, more rostrated area in the left valve andsmaller ratio of siphonal plate in the whole
length of shell: 12 per cent of length in thisspecies, as compared with 20 per cent in thelatter two. It is fairly similar to Caestocorbula
antiqua, sp. nov. in the outline and elongatedarea, but the right valve is more rostrated in thelatter than in the former.
Occurrence:-Rare at loco 2 and common at
loco 4. Probably lower Aptian.

Caestocorbula (s. 1.) ohtai, sp. nov.
Figures 3-12-20
1964. Pulsidis higoellsis (Matsumoto); Ota, p. 153-

329

155, pI. 21, figs. 13-17.
1975. PlIlsidis higoensis (Matsumoto); Hayami, p. 145146.
1977. PlIlsidis higoellsis (Matsumoto); Tamura, p. 141,
pI. 10, figs. 1-6.

Material: -Holotype, KSG-KOSO, internalmould of right valve from loco 6; 11 paratypes;
KSG-K059 - KSG-K06I from loco 8 and KSGKOSI from loc. 6, internal moulds of right valves;
KSG-KOS2 from loco 8 and KSG-KOS7 from loc.
7, external moulds of right valves; KSG-KOS S,
KSG-KOS6, KSG-KOS8 from loc. 8 and KSGKOS3 from loco 7, internal moulds of left valves;
KSG-KOS4, external mould of left valve fromloc.8.
Diagnosis: -Small-sized species of Caestocorbula characterized by the well rostra ted rightvalve and the long sized inner areal part.
Description:-Shell small, moderately inflated,inequilateral, sub trigonal in outline, fairly longer
than high, with right valve larger than left; area
well rostra ted from umbo to postero-dorsal
margin; test comparatively thick; antero-dorsal
margin short and arched; postero-dorsal margin
slightly curved and excavated; anterior margin
convex; ventral margin broadly arched, moreor less concave at about two-thi.rds from anterior
extremity; umbo moderately prominent, slightly
prosogyrate, situated at about one-third of shelllength in right valve and nearly at middle in left;
carina blunt, extended from umbo to posterior
ventral corner; area narrow, long concave; internal mould sulcate from umbo to posterior ventral
margin; shell surface ornamented with regularly
spaced concentric ribs, wider than their interspaces, round-topped, and gradually crowded
from anterior part to posterior; interior of rightvalve grooved for reception of margin of left
valve; inner areal part long rised in median part
towards posterior extremity; supporting buttressprojected behind anterior adductor scar; hinge
plate rather wide and stout; pallial line distinctly
impressed, straight except for lower part of posterior adductor scar; adductor scars fairly large,
subelliptical, posterior one larger than anterior;
cardinal tooth of right valve triangular, roundtopped, separated from dorsal margin side by aTakeshi KOZAI

330

shallow groove; resilial pit large, triangular,situated behind the cardinal tooth, deeply excavated, larger than cardinal tooth; chondrophore small and scarcely prominent.
Measurements (in mm):Sp~cimens

KSG-KOSO. R.in m.
KSG-KOS1. R.in.m.
KSG-K051. R.ox.m.
KSG-KOS3. L.in.m.
KSG·K054. L.ex.m.
KSG-KOS5. L.in.m.
KSG-KOS6. L.in.m.
KSG-K057. R.ex.m.
KSG-K058. Lin.m.
KSG-KOS9, R.in.m.
KSG-K060, R.in.m.
KSG-K061. R.in.m.

L
9.1
9.9
8.5
7.1
7.5
7.1
7.5
8.7+
5.2
8.7+
8.5+
7.5+

H
4.9
5.7

B

4.6

l.8

U
5.3
.\.4
3.6
5.0
3.0
3.3+
4.7
5.0

l.7

U
3.0
3.5
2..7
4.1
4.1
4.4
4.6
3.7
3.3

H/L U/L S/L
0.54 0.33 0.27
2.5 0.58 0.35 0.15
- 0.54 0.31
- 0.68 0.58
- 0.71 0.55
- 0.62 0.62
- 0.48 0.61
- 0.57- 0.43- - 0.58 0.63

~.5

2.6

-

0.55- 0.310.67- --Remarks: -About 50 specimens were collected from the Goshonoura and Mifune Groups
in Kumamoto Prefecture. The specimens whichhave hitherto been called "Pulsidis higoensis(Matsumoto)" are referred to this species.
Matsumoto (1938) described Aloides higoensis based on three specimens from the Goshonoura Group in Kumamoto Prefecture. Later,
Ota (1964) established the genus Pulsidis andincluded Aloides higoensis in this genus, designating UMUT MM7755 (Matsumoto, 1983, pI. 2,
fig. 8) as its lectotype, but the hinge structureof this lectotype was not observed. Its surface
is sculptured, with regular concentric ribs, which
are a little more crowded in the posterior part.
In this respect the lectotype evidently differsfrom Ota's other specimens. Moreover the outline is nearly isosceles triangle in the former, but
subpyriform in the latter. On the other hand,
other two specimens of Matsumoto (1938, textfigs. 9a and 9b), i.e. UMUT MM 7841 and MM
7844, are similar to "Nipponicorbula mifunensis
Ota" or "Pulsidis okadai Ota" in the concave
disk on the middle part and subtriangular cardinal socket. To sum up, it is concluded that
Alaides higoensis Matsumoto, 1938 differs from
"Pulsidis higoellsis" in the sense of Ota (1964).
On the basis of above observations I propose
herein a new name for a species represented by
the Ota's specimens. The specimens treated by
Ota (1964) are deficient in the area of rightvalve. If this part is observed carefully, the innerareal part of the right valve is elongated andraised in the median part. That of left valve is
not raised, and the right valve is fairly elongatedthan the left. Average of SIL is 0.26. These facts
support the idea that this species had siphonal
plate which, however, is not preserved.
Tamura (1979) reported that this specis wascollected with Pterotrigonia (Ptilotrigonia)
mashikensis (Tamura et Tashiro) and Inoceramus
concentricus costatus Nagao et Matsumoto(the latter now emended as Birostrina tamurai
Matsumoto et Noda, 1986). According to Tashiro and Matsuda (1983), P. (P.) mashikensis occurred in the environments of brackish wateror shallow sea water. Consequently this species
must have favoured the environment of morehigher salinity than that of C antiqua, sp. nov.
Comparison: - This new species is similar to
Caestocorbula semina Vokes, 1946, from theAptian of the Lebanon Mountains, in the broadribs, but differs from the latter in the rostratearea and the median ridge on the inner areal
part of the right valve. It is similar to Caestocorbula antiqua, sp. nov. in its elongate area,
but evidently differs in having the ridge on the
inner area of the right valve.
Occurrence:-Common at locs. 6, 7, 8, 9.
Cenomanian.

Caestocorbula (?Parmicorbula) obsoleta
Tashiro et Otsuka
Figures 4-15-18, 20- 22
1982. Caestocorbula (Parmicorbula) obsoleta Tashiro
ct Otsuka, p. 18-19, pI. 5, figs. 15-18,20-22.

Material: - The holotype is an external mouldof right valve (KSG 3053) which was collectedfrom the upper part of the Upper Himenoura
Subgroup at Masuno, Ushibuka City, Kumamoto
Prefecture (ioc. 5) from where 14 specimens(KSG-KI19 - KSG-KI32) are also collected
for the present description.
Diagnosis:-Medium-sized species of Caestacarbula characterized by lack of the carina in
the left valve and less discrepancy between theright and left valves.

848. Caestocorbula from Japan

331

20

Figure 3. 1- 11. Caestocorbula (?Parmicorbula) monobensis, sp. nov. , internal mould s (1 , KSG-K063,
X2.5; 3, KSG-K066, X2.5; 5, KSG-K062 , X2 .5 ; 8, KSG-K069 , X2.5; 10, KSG-K065, X3). Gum cast of externa lmoulds (2, KSG-K071 , X2; 6, KSG-K-72, X2.5 ; 7, KSG-K068 , X2.5; 9, KSG-K073, X2.5). Gum cast of internalmoulds (4 , KSG-K070, X2.5; 11 , KSG-K064 , X2.5).
12- 20. Caestocorbula (s.l.) ohtai, sp. nov., gum cast of ex ternal moulds (12, KSG-K054 , X3 ; 13 , KSGK052, X2.5). Gum cast of internal moulds (15 , KSG-K060 , X2.5; 20, KSG-K058 , X5). Internal moulds (14 ,KSG-K050, X3; 16, KSG-K059 , X3; 17, KSG-K051 , X3; 18, KSG-K055 , X3; 19, KSG-K053 , X2).
21 - 28. Caestocorbula (s.l.) antiqua, sp. nov. , gum cast of external moulds (21, KSG-K084 , X3.5; 26 ,KSG-K082, X3.5). Gum cast of internal moulds (23 , KSG-K079 ; 25, KSG-K085 , X6; 28, KSG-K078 , X4).
Internal moulds (22, KSG-K074 , X3.5; 24, KSG-K077 , X3; 27, KSG-K075, X3.5).

332

Takeshi KOZAI

23
Figure 4. 1- 9. Ca estocorbula (?Parmicorbula) shikamai Ha yami, internal moulds (1 , KSG-K1l4 , X3;
2, KSG-KllO, X3 ; 3, KSG-K120 , X3 ; 5, KSG-K1l5 , X3 ; 6, KS G-K1l6 , X3 .5 ; 9, KSG-K1l3 , X3). Gum cast ofinternal mould (4 , KS G-KllB , X5.5). Gum cast of ex ternal mould s (7 , KSG-K1l2 , X3.5 ; B, KSG-K1l7 , X3.5).
10 - lB. Caestocorbula (?Parmicorbula) obsoleta Tashiro et Otsuka, gum cast of ext ernal moulds (10, KSGKI2B , X3; 11 , KSG-KI23 , X5). Internal moulds (12 , KSG-KI 27, X3.5 ; 13 , KSG-KI24, X4; 14, ISG-K126 , X4 ;15 , KSG-K129, X3.5 ; 16, KSG-KI22, X4 ; 17 , KSG-K125 , X3 ; 1B , KSG-K1l9 , X4.5).
19,20. A 10 ides higoensis Mstsumoto , left valve (19 , MM 7755 , X3). Internal mould (20 , MM 7755 , X3).
21 - 23. Caestocorbula (?Parmicorbula) minima Hayami, right valve (21 , MM 9764, X3). Left valv es (22 ,MM 9764 , X3 ; 23 , MM 9765 , X3).

848. Caestocorbula from Japan
Description:-Shell medium-sized, moderately
inflated, subtrigonal, a little longer than high;right valve a little larger than left; test thcik;
antero-dorsal margin broadly arched; posterodorsal margin weakly concave near the umbo;
ventral margin broadly arched; posterior margin
vertically truncated; umbo situated at about midlength of the valve, very prominent and slightly
prosogyrate or orthogyrous; surface ornamented
with concentric ribs; inner areal part flat; cardinal tooth of right valve triangular, strongly projected, but rounded at top; resilial pit large anddeep, situated behind the cardinal tooth.
Measurements (in mm):Specimens
KSG-K1l9. R.in.m.
KSG·KI20, R.in.m.
KSG·KI2I, L.ex.m.
KSG·KI22, L.in.m.
KSG-K123, L.ex.m.
KSG·KI24, R.m.m.
KSG·KI25, R.m.In.
KSG-K126, R.in.m.
KSG-KI27, L.in.m.
KSG-K129, R.in.m.

LH
7.5 4.9
8.3 5.5
6.9 5.1
7.3 6.0
9.2 6.9
6.2 4.9
10.2+ 8.2
7.1 3.3+
7.0 5.5
10.9 8.3

B

2.0

1.5

U
3.9
3.6
3.7
3.5
4.6
3.5

0.8
0.7

~.5

3.7
3.8
5.2

0.6

H/L U/L SIL
0.65 0.52 0.11
0.66 0.43 0.08
0.74 0.54
0.82 0.48
0.75 0.50
0.79- 0.56- 0.80- 0.44- 0.46+ 0.52
0.79 0.54
0.76 0.48 0.04

Remarks:-Numerous specimens were collected from the type-locality. Almost all of themlook smooth on the surface, owing to pre-depositional abrasions, but a few specimens (Le. KSGK123 and KSG-KI2S) have distinct concentricribs which are counted about 4 in the distanceof 1 mm along the height in the central part ofadult specimen, Ratio S/L is about O_OS whichis the smallest among species of the genus Caestocorblila. In this respect this species is similar to
Caestocorbliia shikamai Hayami, but the latterhas more strongly inflated valve and shorter area.
It is similar to Parmicorbliia vokesi Stephenson,
1953 from the Woodbine Formation of Texas,
in el~ngated area, but is distinguished from thelatter by its more longly rostrated left valve.
Occllrrcllce:-Abundant at loco 5. Maastrichtian.
Further remarks
In this paper six species of the genus Cacstocorbliia are described.

333

Brackish-water•• ·-'S'hallow-ma ri ne... ----------------:---- - - - - - - - - - - --- - - C.antlqua
C.ohtalC.monobensis
C.mlnima
C.obsoleta
C. 5 h i ka m a I

Figure 2. Environments of Caestocorbula in Japan.

I. The specimens belonging to the genus
Caestocorbliia in Japan occur in the brackishwater deposits and shallow-marine deposits.
From the environmental point of view, the six
species may be divided into two or three categories as shown in Figure 2.
2. The shallow-marine species have shellforms similar to those of Parmicorbula, but the
species which lived in the brackish-water haveshell forms which differ from Parmicorbula.
However, it is difficult to determine the subgenus
of either Parmicorbula or Caestocorbula, because
the siphonal plate is often unpreserved.
Acknowledgments
I wish to express my thanks to Professor
Masayuki Tashiro of Kochi University, for his
pertient instruction and reading the first draft.
Thanks are also due to Emeritus Professor
Tatsuro Matsumoto of Kyushu University, for
his critical reading the manuscript with encouragement, Emeritus Professor Yoshihisa Ohta
(Ota) of Fukuoka University of Education,
Professor Itaru Hayami of the University ofTokyo, Mr. Masao Otsuka of Kogen Junior-highSchool in Kumamoto, and Dr. Tomoki Kase of
National Science Museum for their kind helps
for this study.
References cited
Cox, L. R. et al. (1969): Treatise on invertebrate
paleontology. Pt. N. (2 vols). 952 p. Ceol. Soc.
America and Univ. Kansas.
Hayami, I. (1966): Lower Cretaceolls marine pelccypods of Japan. Part 3, Mem. Fac. Sci., Kyushu
UI/iv., Se/". D, vol. 17, no. 3, p. 151-249, pis. 22-

334

Takeshi KOZAI

26·.
--(1975): A systematic survey of the Mesozoic
Bivalvia from Japan. Bull. Univ. Mus., Ulliv.
Tokyo, no. 10, p. 1-228, pIs. 1-10.
--and Oji, T. (1980): Early Cretaceous Bivalvia fromthe Choshi district, Chiba Prefecture, Japan. Trans.
Proc. Palaeont. Soc. Japan, N. S., no. 120, p.
419-448, pIs. 51-53.
Kozai, T. (1986): Early Cretaceous Pulsidis (Bivalvia)
from Japan. Ibid., no. 144, p. 479-489, pI. 95.
Matsumoto, T. (1938): Geology of Goshonoura Islands,
Amakusa, with special reference to the Cretaceous
stratigraphy (in Japanese), with preliminary notes
on some of the more important fossils among the
Goshonoura fauna (in English). Jour. Ceol. Soc.
Japan, vol. 45, no. 532, p. 13-26, pIs. 1-2.
--and Noda, M. (1986): Some Inoceramids (Bivalvia)
from the Cenomanian (Cretaceous) of Japan - 1
new or little known four species from Hokkaido
and Kyushu. TrailS. Proc. Palaeont. Soc. Japan,
N. S., no. 143, p. 409-421, pIs. 81-85.
Ota, Y. (1964): On some Cretaceous corbulids fromJapan. Mem. Fac. Sci., Kyushu Ulliv., Ser. D,
Ceol., vol. 15, no. 1, p. 149-161, pIs. 20-21.
Stephenson, L. W. (1953): Larger invertebrate fossilsof the Woodbine Formation (Cenomanian) of
Texas. U. S. Ceol. Surv. Prof. Pap., 242, p. 1-226,
pIs. 8-59.
Tamura, M. (1977): Cenomanian bivalves from the
Mifune Group, Japan (Part 2). Mem. Fac. Educ.,

Kumamoto Univ., no. 26, Nat. Sci., p. 107-144,
pIs. 1-13.
--(1979): Cenomanian bivalves from the Mifunc
Group, Japan (Part 3). Ibid., no. 28, Nat. Sci. p.
59-74, pIs. 1-3.
Tashiro, M. and Matsuda, T. (1983): Stratigraphy andinhabited environments of the Cretaceous Trigonians in Japan. Kaseki (Fossils), no. 34, p. 1932 (in Japanese with English abstract).
--and - - (1986): Lower Cretaceous bivalves fromthe Sakawa area, Shikoku. TrailS. Proc. Palaeont.
Soc. Japan, N. S., no. 142, p. 366-392, pIs. 74-

77.
- - and Otsuka, M. (1980): Bivalve fossils from theUppermost Formation of the Upper Himenount
Subgroup in Amakusa-Shimojima Island, Kyushu(Part 1). Mem. Fac. Sci., Koclzi Ulliv., Ser. E, vol.
3, p. 7 -22, pIs. 3-5.
- - and - - (1982): Bivalve fossils from the Uppermost Formation of the Upper Himenoura Subgroup in Amakusa-Shimojima Island, Kyushu(Part 2). Ibid., vol. 3, p. 7-22, pIs. 3-5.
Vokes, H. E. (1945): Supraspecific groups of thepelecypod family Corbulidae. Bull. A mer. Mus.,
Nat. Hist., vol. 86, art. 1, p. 1-32, pIs. 1-4.
- - (1946): Contributions to the paleontology of the
Lebanon Mountains, Republic of Lebanon. Part 3.
The pelecypod fauna of the "Olive locality"(Aptian) at Abeih. Ibid., vol. 87, art. 3, p. 143215, pIs. 1-10.

Asanoyabu l:\l;j(, Doiban ±~~, Fukuda ffi\[], Hiroyasu J1;.'K, Kaminaro J::.~§, Katsuura ~lfIi, Kawauchida JII P-JEB, Kitakawauchi ~tJII P'J, Masuno .f.1!llllf, Matsunoo .f'~ / 1=., Mifune mI1Yd,
Monobe ¥l.J {ffl, Satoura !!. ilfi, Seto ifJi pi, Tashiro FIl f~, Tazukawa (Tatsukawa) 11. JII ,Tsuzumugi *j[~, Ushibuka lf~, Yabe $'i:{ffl, Yasumaru 'K:A, Yokose ltttifJi.

El *0) ~LiJIi:*il Caestocorbula ~~.:. -:n ,-c : ,: tL;J: -c:.~~ ~tL -c ~ t.: 'b 0) 'b ~/Jb-C, *:fII B.iJIi:*O)lO.t\!! ..i:V.1' Gil Lt.: Caestocorbula ~O)(t::fi~¥}~M L, -i"tL G ~ 61l1!~.:.~~ L, %1lI!0)!f,f1ft~JjfjGtJ,~.:. Lt.:o 61l1!0)<p~':'I;!:', 3 ¥rfiJi, C. antiqua, sp. nov., C. monobensis, sp. nov., C.
ohtai, sp. nov., iJ;~;J:tL7.>om:i1§ fi!:Trans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 335-345,4 Figs., December 30, 1987

849. MIDDLE CARBONIFEROUS ORTHOCERATACEAE AND
PSEUDORTHOCERATACEAE(MOLLUSCA:CEPHALOPODA)
FROM THE AKIYOSHI LIMESTONE, YAMAGUCHI PREFECTURE(MOLLUSCAN PALEONTOLOGY OF THE AKIYOSHI LIMESTONE GROUP-VIII)*
SHUJI NIKO
Department of Earth Science and Astronomy, College of Arts and Sciences,
The University of Tokyo, Komaba, Tokyo 153

TAMIO NISHIDA
Department of Earth Sciences, Faculty of Education, Saga University, Saga 840

and
YUKO KYUMA
Yagami Elementary School, Nagasaki 850-01

Abstract. The Akiyoshi Limestone Group (Early Carboniferous to Middle Permian) in
Yamaguchi Prefecture contains a diverse fossil molluscan fauna, including cephalopods. In thispaper, we describe for the first time 6 species of orthocerid cephalopods from the Isa area
where lies in the southwestern margin of the Akiyoshi Limestone Plateau (s.I.). Stratigraphic
levels and lithofacies of the cephalopods locality are divided into two types i.e., 1) Bioclastic
grainstone, rich in crinoid fragments, of the Pseudostaffella antiqua zone (Bashkirian) including
Brachycycloceras sp. indet. and 2) Coquinite of the Fusulinella biconica zone (Moscovian),limestone of which yields Brachycycloceras akiyoshiellsis, sp. nov., Geisonoceras sejunctus,
sp. nov., Geisollocerina cribrella, sp. nov., Striacoceras (?) sp. indet. and Reticycloceras (?) sp.
indet.

(Nishida and Kyuma, 1982, 1984, 1985, 1986;
Nishida et al., 1985; Kyuma and Nishida 1987).
Those series of papers have resulted in theidentification of 45 ammonoid species, including
5 new genera and 21 new species, however, so
far as other cephalopod taxa on a large quantity
i.e. Nautiloidea and Bactritoidea are concerned,
little work has previously been accomplished.
The purpose of this report is to describe 6 speciesof Nautiloidea induding Brachycydoceratidae,
Geisonoceratidae and Pseudorthoceratidae, representatives of which were collected by T.N. andy. K. in cooperation with many students of Saga
University from two localities (Loc. 1M 01; 1M60) in the Isa area of southwestern margin of the

In trod uction
Since Ozawa's classical paper in 1925 on
fusulinids, there are many paleontological works
on rich and varied Akiyoshi flora and fauna that
include algae, foraminifers, conodonts, echinoderms, brachiopods, bryozoans, corals, arthropods and molluscus. Among them, descriptionof cephalopods fauna in the Akiyoshi LimestoneGroup and from the slump blocks of limestone
in terrigenous sediments in the surrounding area
began with Nishida (1971) and was followed bylater paleontological and biostratigraphical studies*Received August 20, 1987; Studies on Japanese Trilobites and Associated Fossils-LVI.

335

Shuji NIKO, Tamio NISHIDA and Yuko KYUMA

336

Figure 1.

Location map of the Isa area, southwestern margin of the Akiyoshi Limestone Plateau (s.l.).

Akiyoshi Limestone Plateau (s.I.), Mine City,
Yamaguchi Prefecture (Figure 1).
The Akiyoshi Limestone is a large body(about 8 x 16 km across) of reef complex thatwas deposited on the top of a seamount throughthe late Tournaisian (Early Carboniferous) tolate Guadalupian (Middle Permian) age. It forms
a tectonic collage together with siliceous deposits(Beppu Group) synchronous with the limestonebody, and terrigenous clastic sediments (Tsunemori Group; Ota Group) of probably Middle toLate Permian, whose emplacement was ascribedto the subduction of pre-Late Triassic age (Kanmera, 1983; Kanmera and Nishi, 1983; Uchiyama
et al., 1986). The lithofacies and biostratigraphyof the Akiyoshi Limestone have been describedin detail (Ozawa, 1923; Toriyama, 1954, 1958;
Okimura, 1963; Eto, 1967; Ota, 1968; 1977;
Nagai, 1978; Matsusue, 1986). Thus, only abrief outline will be given here. Ota (1968) described 16 limestone-types on the basis of a reeflagoon dual concept and suggested that the

Akiyoshi Limestone might represent a carbonate
depositional environment of organic reef complex with a core of hermatypic corals, bryozoans
and algae, and analogous to the modern oceanic
fringing reef to atoll. Biostratigraphically, the
Akiyoshi Limestone is divided into 21 zones
based on the combination of fusulinaceans andsmaller foraminifera (Endostaffella) as a supplementary element in the pre-middle Visean part.
Besides one specimen (Brachycycloceras sp.
indet.) the cephalopods occur in coquinoid limestone in Loc. 1M 60 which consists mainly ofammonoid shell with thick fibrous spar crusts incavities ("Grossoolith") of early diagenetic origin
in reefy environment and is associated closelywith bafflestone and bindstone of true reef facies
of Ota's definition. In this rock, specimens of
Orthocerida are relatively rare in comparison
with ammonoids, and 9 individuals are recognizedso far, including Brachycycloceras akiyoshiensis,
sp. nov., Ceiso/loceras sejunctus, sp. nov., Ceisollocerilla cribrella, sp. nov., Striacoceras (?) sp.

849. Carboniferous cephalopods from Akiyoshi
indet. and Reticycloceras (?) sp. indet. Fusulinids
from this interval represent the Fusulinella biconica zone (Moscovian). On the other hand,
Brachycycloceras sp. indet. collected from Loc.
1M 01 of bioclastic grainstone, rich in crinoid
fragments, of the Pseudostaffella antiqua zone
(Bashkirian) .
Materials used in this paper are registered anddeposited in the Akiyoshi-dai Museum of Natural
History (ASM).
Acknowledgments.- We are deeply grateful toDrs. T. Kobayashi of the Japan Academy and T.
Hamada of The University of Tokyo for theirbeneficial discussion and critical reading of themanuscript. Many students, including Mr. Hirofumi Kuga, of Saga University were of great
help in collecting and adjusting samples for thisstudy.
Systematic paleontology
Superfamily Orthocerataceae M'Coy, 1844
Family Brachycycloceratidae Furnish,
Glenister and Hansman, 1964
Genus Brachycycloceras Miller,
Dunbar and Condra, 1933
Brachycycloceras Miller, Dunbar and Condra, 1933, p.
105-107; Demanct, 1941, p. 102; Flower, 1943,
p. 124; Shimer and Shrock, 1944, p. 539; Schmidt,
1956, p. 47; Balashov and Zhuravleva, 1962, p. 8485; Furnish, Glenistcr and Hansman, 1962, p. 13451347; Furnish and Glcnistcr, 1964, p. K232;Gordon,
1964, p. 107-108; Shimansky, 1968, p. 67.

Type species:-Brachycycloceras
normaleMiller, Dunbar and Condra, 1933.
Diagnosis: -Brachycycloceras consisting oforthoconic to gently cyrtoconic deciduous conchwith annulations and truncated mature conch.
Cross section circular to sub circular or quadrate.
Mature part breviconic, strongly inflated andweakly sculptured. Camerae relatively short.
Septa form shallow lobe at venter and dorsum,
and corresponding saddle on each flank. Siphuncle
subcentral to subventral and small; septal necks
short and suborthochoanitic. Siphuncular segments slightly expanded in camerae.

337

Remarks:-The generic description given
above is essentially the same as that of Furnish,
Glenister and Hansman (1962), which is acceptedwithout any emendation. The genus Brachycycloceras has been reported previously from thewestern Europe (Belgium; Germany), U.S.S.R.
(Moscow Basin; Urals; Kirgizskaya S.S.R.) andNorth America. The known specimens are confined to occur in the late Early to Late Carboniferous.
Brachycycloceras akiyoshiensis Niko,
Nishida and Kyuma, sp. nov.
Figures 2-1, 2

Material:-Holotype, ASM 51301 from Loc.
1M 60 (Fusulinella biconica zone).
Diagnosis:-Relatively large, slightly cyrtoconic Brachycycloceras with sub circular crosssection. Ornamented with weakly sinuous annulations and fine lirae.
Description:- The hologype, only known
specimen of Brachycycloceras akiyoshiensis, is a
deciduous portion, about 36 mm long. The
conch is slightly cyrtoconic with subcircular crosssection, expanding from about 10 mm to 17 x
18 mm over a length of the fragmented specimen. Prominently rounded and slightly sinuous
annulations occur both on shell surface andthe internal mould of shell. Annulations arenearly transverse to the conch axis; oral, five to
six annuli occupy a length equal to the adoralshell diameter. Interspaces of adjacent crest aremarked by a series of fine lirae, which are parallelto annulations.
Discussion:-The initial stages and mature portion of this species are not known; besides, nointernal structures are preserved. However, theslightly cyrtoconic and relatively large shell are
the most distinctive features separating Brachycycloceras akiyoshiensis from most of othersepcies of the genus.
Brachycycloceras normale Miller, Dunbar
and Condra (Miller et al., 1933, pI. 3, figs. 3-5:
Furnish et al., 1962, pI. 179, figs. 2-4, pI. 180,
figs. 7, 8, 10, 11) described from the Desmoinesian to Virgilian of the Midcontinent Region,

338

Shuji NIKO, Tamio NISHIDA and Yuko KYUMA

North America seems to be referable to B. akiyoshiensis, although the former has more rapidly
expanding orthoconic shell and smaller shell
diameter in corresponding stages. This species
somewhat resembles B. washingtonense Gordon(Gordon, 1964, pI. 5, figs. 4, 5, pI. 16, figs. 4, 5,
text-fig. 10) which was described from the
Fayetteville shale (Upper Mississippian) of
Arkansas, but differs in its more prominent
annulation and smaller shell size.

Brachycycloceras sp. indet.
Figures 2-5, 6Material:-ASM 51302 from Loc. 1M 01(Pseudostaffella antiqua zone).
Descriptive remarks: - The examined specimen
is a decollated 10ngicone, about 33 mm in length,
broken at the both ends. The conch is orthoconic
circular in cross section, which expanding from
5.0 mm to 12.2 mm over a length of the fragmented specimen. Surface is marked by a seriesof narrowly rounded annulations, which areslightly oblique to the long axis of the conch.
Septa are shallow, forming almost straight andtransverse sutures. Siphuncular structure of thisspecimen is not known.
This specimen is tentatively assigned to thegenus Brachycycloceras on the basis of its shell
shape and characteristic surface ornamentation.
Brachycycloceras subquadratum Shimansky(Shimansky, 1968, pI. 3, figs. 4, 5) from the
Visean and Namurian rocks of southern Urals
and Kirgizskaya S.S.R. somewhat resembles thisspecimen. But sub quadrate cross section, characteristic to B. subquadratum, is not observedin the present material.
Family Geisonoceratidae Zhuravleva, 1959
Genus Geisonoceras Hyatt, 1884

Geisolloceras Hyatt, 1884 (flower, 1939); flowr, 1939,
p. 163-164; Shimer and Shrock, 1944, p. 537:
Balashov and Zhuravleva, 1962, p. 85; Sweet, 1964,
p. K236-K237.

Type species: -OrtllOceras rivale Barrande,
1866.

Diagnosis: -Slender orthocone to gently cyrtocone with circular to subcircular cross section.
Sutures straight, transverse or slightly oblique,and surface marked by transverse bands. Siphuncle orthochoanitic to suborthochoanitic andcentral to subcentral. Cameral and endosiphuncular deposits well developed.
Discussion:- The genus Geisonoceras was established by Hyatt based on Orthoceras rivale
Barrande in 1884. Flower (I 964 ) regarded
Barrande's Orthoceras rivale as "a good Michelinoceras" and indicated that the boundary of
Geisonoceras and Michelinoceras is not clear.
We regard the genus Geisonoceras as a distinct
taxon based on not having a small and empty siphuncle, relatively long and thin necks, andsmooth shell surface characteristic to Michelinoceras. However, there is a possibility that the
species which have been attributed to Geisonoceras would be an artificial grouping. The specimens studied here are fragmentary and having
ill preserved internal structures, making taxonomic interpretation difficult. Thus, the present
identification is tentative.
Geisonoceras has previously been known from
North America, Eurasia and Asia of the Middle
Ordovician to Late Devonian.
Geisonoceras sejunctus Niko, Nishida
and Kyuma, sp. nov.
Figures 3-1-6

Material:-Holotype, ASM 51303 (Figures 31-3, 5, 6); paratype, ASM 5 1304 (Figure 3-4).

~ Figure 2.
1,2. Brachycycloceras akiyoshiellsis Niko, Nishida and Kyuma, sp. nov. Holotype, ASM 51301:
1, lateral view, venter on left, X2; 2, dorsal view, X2. 3,4. Reticycloceras (?) sp. indet. Figured" specimen, ASM
51309: 3, ventral (?) view, X3; 4, lateral view, venter (?) on left, X3. 5, 6. Brachycycloceras sp. indet. Figured
specimen, ASM 51302: 5, lateral view, venter on right, X2; 6, ventral view, X2. 7-8. Striacoceras (?) sp. indet.
Figured specimens, ASM 51300: 7, lateral view, X4; 8, vertical thin section, XlO.5; 9, partial enlargement at
septal foramen of Figure 2-8, XI3.5.

849. Carb oniferous cephalopods from Akiyoshi

339

340

Slzuji NIKO, Tamio NISHIDA and Yuko KYUMA

The specimens studied are form Loc. 1M 60

ceras teiclterti Flower (Flower, 1939, pI. 7, fig.

(FlIsulinella biconica zone).
Diagnosis: -Geisonoceras with slender ortho-

8, pI. 9. fig. 19) appears similar to the internal
structure of G. sejunctus. The Middle Devonian
form, collected from the Onondaga Limestone
in New York, is distinguished from Geisonoceras
sejullctus in having larger siphuncu1ar size andshorter septal necks.

cone, straight sutures and shell surface marked
by transverse, narrow imbricate bands. Siphuncle
central, relatively small; septal necks short andorthochoanitic; connecting rings cylindrical.
Descriptioll:-Holotype, ASM 51303; The
holotype is a portion of an orthoconic phragmocone, 25 mm long, with a circular cross section.
Diameter of the conch 8.5 mm near the apicalend. Shell surface marked by a series of transverse and narrow imbricate bands. Bands are flat,slightly irregular in width, and sometimes forming weak salient (Figure 3-2); their lower margins
abruptly delineated. Sutures are straight andtransverse. Curvature of septa is relatively deep.
This specimen revealed two and one-half cameraein the thin section. An apical camera occupies
a length to the adoral conch diameter, ado rally ,camera has a half length of the adoral conch
diameter. Siphuncle is central and relatively
small for the genus, 1.10 mm across. Septal necks
are short, stout and straight, joined by thin
cylindrical connecting rings. Both siphuncle
and camera are apparently devoid of organic
deposits.
Paratype, ASM 51304; This represents a portion of phragmocone in more earlier stages thanthe holotype. The conch orthoconic of 47 mm
long, circular in section which expands in alength of 39 mm from 6.0 mm to 8.5 mm. Surface is somewhat weathered, and ornamentationof the specimen is almost identical to that of
the holotype. Sutures and internal structures
are not observed.
Discussion:- The relatively long camerae andcylindrical connecting ring of Geisolloceras
sejunctus is, in some respects, atypical of Geisonoceras which possesses two to two and onehalf camerae par adoral conch diameter andexpanded connecting ring. In addition, the bandof surface ornamentation of the type species ofGeisonoceras rivale (Barrande) (Sweet, 1964,
fig. 169, 6) possesses many times the width incomparison with that of the examined specimen.
The only Middle Devonican species of Geisollo-

Genus Geisollocerilla F oerste, 1935
1935 Geisonocerina Foerste, p. 22; Shimer and Shrock,1944, p. 539; Flower, 1945, p. 682; Schmidt, 1956,
p.50.
1964, ? Geisonocerina, Sweet, p. K237.
1968, Geisonocerina, Shimansky, p. 69-70.

Type species:-Orthoceras wauwatosense Whitfield, 1882.

Diagllosis:-Geisonocerilla is applied to longiconic orthocones with a circular cross section.
Surface ornamented by fine transverse lirae, andsometimes occurs weak longitudinal lirae. Sutures straight, transverse or slightly oblique.
Camerae relatively long. Septal necks short,orthochoanitic to suborthochoanitic, joined bycylindrical connecting rings.
Remarks:-This genus was proposed byFoerste in 1935 for taxa with Geisonoceras-like
orthoconic cephalopods but distinguished inhaving the close raised transverse lirae insteadof bands. The internal structure of the typespecies has not been figured. The genus Geisollocerina has been reported previously from Upper
Ordovician to Middle Carboniferous.
Geisonocerilla cribrella Niko, Nishida
and Kyuma, sp. nov.
Figures 4-1- 8

Material:-Holotype, ASM 51305 (Figures 41, 2,4, 7); paratypes, ASM 51306 (Figures 4-3,
5, 6), ASM 51307 (Figure 4-8); unfigured specimen ASM 51308. The studied specimens wereobtained from Loc. 1M 60 (Fusulinella bicollicazone).
Diagnosis:-Geisollocerilla with slender orthocone and shell surface marked by slightly undulated transverse Iirae and weak longitudinal

849. Carboniferous cephalopods from Akiyoshi

341

1

4

Figure 3. 1- 6. Geisonoceras sejullctus Niko, Nishida and Kyuma, sp. nov. Holotype, ASM 51303: 1,
lateral view, X2; 2, partial enlargement of shell surface showing narrow imbricate bands and weak salients, X6;
3, polished cross section near the apical end, X5; 5, vertical thin section, X6; 6, partial enlargement at septal
foramen of Figure 3-5, X 13.5. Paratype, ASM 51304: 4, lateral view, X3.

342

Shuji NIKO, Tamio NISHIDA and Yuko KYUMA

Figure 4. 1 -8 . Geisonocerina cribrella Niko , Nishida and Kyuma , sp. nov. Holotype, ASM 51305: I,
lateral view, X3, 2, polished cross section near the apical end, X5; 4, ver tical thin section, X12; 7, partial enlargement of shell surface, X6.5. Para type , ASM 51306: 3, lateral view, X2; 5, partial enlargement of exfoliated partof shell showing ornamentation of "wrinkled layer", X6.6; 6, partial enlargement of shell surface at overlapped
part of ornamentation, X6. Paratype, ASM 51307 : 8, lateral view, X3 .

849. Carboniferous cephalopods from Akiyoshi
lirae. Siphuncle central; septal necks relatively
long and orthochoanitic; connecting rings slightly
expanded in camerae.
Description:-Holotype, ASM 51305: The
holotype consists of a phragmocone of longiconic orthocone, 21 mm long. Cross section of
the shell is oval probably because of the secondary deformation. Surfaces marked by a series ofslightly undulated transverse lime and weaklongitudinal lirae. Sutures are not observed, butthey are assumed to be transverse to the long axisof the conch. Camerae are relatively long; one to
one and one-half camerae occupy a length equal
to the adoral conch diameter. Siphuncle iscentral, cin;ular in cross section and with a diameter of 0.9 mm at the septal foramen. Septal
necks are thin, relatively long and orthochoanitic.
Siphuncle segments are slightly expanded incamerae. No cameral and siphonal deposits areevident.
Paratype, ASM 51306: The specimen is a
fragment of the body chamber, somewhat crushed, and about 46 mm long. Surface is ornamented by a series of slightly sinuous transverse lirae
sometimes forming salients (Figure 4-6). Longitudinal lirae are very weak, besides partly disappeared. On exfoliated part of the shell, "wrinkled
layer" appears to be developed on internal mould(Figure 4-5).
Paratype, ASM 51307: This is a portion of theorthoconic phragmocone, 24 mm long. Conchcircular in cross section, and its diameter near
the apical end is 6.7 mm. Well preserved surface
ornamentation is seen on this specimen. Surfaceof the specimen bears a series of transverse lirae
which are slightly sinuated and form weak salients. Fine longitudinal lirae also occur on theshell surface. These longitudinal lirae are developed only at interspaces of the transvers lirae.
No internal structures are observed.
Discussion: - The present species somewhat
resembles Geisonocerina homeocincta Shimansky(Shimansky, 1968, pI. 3, figs. 7,8) which occurs
in the early Namurian rocks of southern Urals.
However, the presence of longitudinal Ii rae
and weak salients of transverse Iirae make G.
cribrella the most easily recognizable features of343

this new species of Geisonocerina.
Somewhat similar surface ornamentation withthe examined specimens appears in some Carboniferous species of Dolorthoceras and Sueroceras.
However, these specimens are assigned to Geisonocerina, rather than the above-mentioned two
genera, because of their less constricted siphuncle
at the septal foramen.
Genus Striacoceras Flower, 1936

Striacoceras (?) sp. indet.
Figures 2-7-9

Material:-ASM 51300 from Loc. 1M 60(Fusulinella biconica zone).
Descriptive remarks:- The examined specimen
is a portion of the slender orthoconic phragmocone, 14 mm long. Cross section of the shell iscircular, and with apical diameter of 4.4 mm.
Surface is ornamented with cancellate markings
which are produced by intersecting longitudinal
and transverse Iirae. Sutures are slightly obliqueto the long axis of the conch. About one camera
occupies a length equal to the apical conch diameter. Curvature of septa is deep. Siphuncle iscentral and relatively large for the corresponding
shell diameter. Septal neck is long and orthochoanitic, joined by thin cylindrical rings. Bothsiphuncle and camerae are apparently devoid oforganic deposits.
In tentatively assigning this specimen to
Striacoceras, rather than Protokionoceras, because of its slender shell. And the lack of strongly prominent longitudinal ribs and its relatively
large siphuncle are the most distinctive features
separating Striacoceras (?) sp. indet. from thespecies of the subfamily Kionoceratinae.
Superfamily Pseudorthocerataceae
Flower and Caster, 1935
Family Pseudorthoceratidae
Flower and Caster, 1935
Genus Reticycloceras Gordon, 1960

Reticycloceras (?) sp. indet.
I:igurcs 2-3, 4

344

Shuji NIKO, Tamio NISHIDA and Yuko KYUMA

Material:-ASM 51309 from Loc. 1M 60(Fusulinella biconica zone).
Descriptive remarks:-Only a fragmentary
specimen is available for this study. This figured
specimen is an annulated orthocone, about 18
mm long. Cross section of the shell is depressed,
expanding from 10.5 x 8.5 mm to 11.8 x 10.5mm over a length of the fragment. Annuli are
weak, rounded and slightly oblique to the longaxis of the conch. In addition, surface is marked
by a numerous transverse lirae, and edges of lirae
are minutely and somewhat irregularly crenulated. No internal structures are preserved in thespecimen examined.
This specimen is questionably assigned to
Reticycloceras because of the similarity of its
surrace ornamentation to that of the R. croneisi
Gordon (Gordon 1960, pI. 27, figs. 9-11; 1964,
pI. 6, figs. 9-14, 25-28, 32).

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General geology of the Akiyoshi Limestone Group.
Ibid., no. 12, p. 1-33, pIs. 1-3.
Ozawa, Y. (1923): Stratigraphical study on the socalled Upper Chichibu Formation including the
Akiyoshi-dai Limestone. Jour. Geo/. Soc. Japan,
vol. 30, no. 357, p. 227-243 (in Japanese).
- - (1925): Paleontological and stratigraphical studies
on the Permo-Carboniferous limestone of Nagato,Part II, Paleontology. Jour. coll. Sci., Imp. Univ.,
Tokyo, vol. 45, no. 6, p. 1-90, pIs. 1-14.
Ruzhentsev, V. E., Shimansky, V. N., Zhuravleva,
B.A. and Balashov, Z. G. (1962): PYIKeHueB,
B. E., W.IIMaHcKldi, B. H., )KypaBJIeBa, <1>. A. II
BaJIall\OB, 3. f. OCHOBbi naJIeOHTOJIomii, MOJIJIIOCKII-fOJIOBOHOrlle I. i1agamellbcmoo A"ag.

345

Hay" CCCfJ Moclioa, CTp. 1 1~8, raoJI I 89.
Schmidt, H. (1956): Orthocone cephalopoden aus dem
deutschen Unterkarbon. Pa/iiollt. Zeitschr., vol. 30,
no. 1-2, p. 41 -68, pIs. 2-4.
Shimansky, V. N. (1968):
W.IJMmICKIJii. B. H.
KaMelilloyrollbllble Orl hocerat ida. Oncocerat ida,
Actinoceratida II Bactritida. AKag. Hay" CCCP,
Tpyabl na.zeo/im. i1Hcm., TOM 117, CTp. 1··
lSI, Tao.~. 1·20.
Shimer, H. W. and Shrock, R. R. (1944): Index fossilsof North America. New York, John Wiley, p. 1837, pIs. 1 -303.
Teichert, C, Kummcl, B., Sweet, W. C, Stenzcl, II. 13.,
Furnish, W. M., Glenister, B. F., Erben, H. K.,
Moore, R. C. and Zeller, D. E. (1964): Treatise
on invertebrate paleontology, Part K. Mollusca 3.
Moore, R. C., ed., Geo/. Soc. America and Kansas
Univ. Press, p. KI-K519.
Toriyama, R. (1954): Geology of Akiyoshi. Part I.
Study of the Akiyoshi Limestone Group. Mem.
Fac. Sci. Kyushu Ulliv., Ser. D, vol. 4, no. 1, p.
39-97.
--(1958): Ditto. Part III. Fusulinids of Akiyoshi.
Ibid., vol. 7, p. 1-264, pIs. 1-48.
Uchiyama, T., Sano, H. and Kanmera, K. (1986): Depositional and tectonic settings of cherts aroundthe Akiyoshi Limestone Group, southwest Japan.
Ibid., vol. 26, no. 1, p. 51-68, pIs. 6 -8.

Akiyoshi tkflf, [sa {)tftc, Mine ~19Ji.

tktr15 )jJ(¥i7J' I? (J)15 ER*C if' WJl!IUE.~ Orthocerataceae, Pseudorthocerataceae : tk 1'i15 IR:'0 Nlillf
7J' I? lillJtJE.m~~t?~·lild,,$.k{2/>Jj;lJ¥J.J{I::15./lF~.gjHI:l1' 7.:>. *~lfij"('li, tktrE(J)mgfj~~-:.{il.~1' 7.:>ff1'

ftc • • l~.WLk6.(J)~~~«~~~M(J)llJtJE.~~,tktr.~~~~~~E.1'7.:>. _JE.m{I::15 (J). W~ i:\!i:to l r.J ¥i -/{IIi, (I)Brachycycloceras sp. indet. ~. Wl' 7.:> Psendostaffella
CBashkirian) (J) #Ii S il- Jt ~-:. E; t; bioclastic grainstone, (2) Brachycycloceras
antiqua**akiyoshiensis, sp. nov., Geisonoceras sejunctus, sp. nov., Geisonocerina cribrella, sp. nov.,
Striacoceras (?) sp. indet., Reticycloceras (?) sp. indet. ~ • 11l l' 7.J Fusulinella biconica
CMoscovian)(J) coquinite ~-:'=7J~.n7.:>.

!'\'~T-~ffj . gfjlIlKIiIE - ~r.1jmTTrans. Proc. Palaeont. Soc. Japan, N. S., No. 148, pp. 346-359,4 figs., December 30, 1987

850. EARL Y SHELL MORPHOLOGY OF KARSTENICERAS(ANCYLOCERATID) FROM THE LOWER CRETACEOUS CHOSHI GROUP,
JAPAN AND ITS SIGNIFICANCE TO THE PHYLOGENY
OF CRETACEOUS HETEROMORPH AMMONITES*MASAKI MATSUKAWA
Department of Earth Sciences, Faculty of Science, Ehime University, Matsuyama 790

Abstract. Karsteniceras obatai, sp. nov., (Ancyloceratinae) from the Barremian Kimigahama Formation of the Choshi area, Kwanto district is described. The classification and phylogeny of heteromorph ammonites at supra-superfamily level is discussed on the basis of theinternal shell features of the early ontogeny in this species. K. obatai is allied to Karsteniceras
asiaticum (Yabe et Shimizu) in shell form; both possessing a ventral groove on the middle stageof each chamber, but the new species is distinguished by the stoutly ventra-lateral tubercles on
the ribbing at mid-whorl and by the numerous lirae on the later whorl. These two species are
considered to have derived from a common ancestral species. Some internal structural featuresof the nepionic stage of the shell of K. obatai are observable. One of the features, the siphuncular position, is interpreted as providing an important evidence for the classification and phylogeny of heteromorph ammonites at ordinal level, and that the existing classification of theseammonites is polyphyletic.

internal structural features of early shell ontogeny of the planispiral ammonites are moreeasily observed, because the adult shell partly
encloses its early shell growth. On the other
hand, the early whorls of heteromorph ammonites are not always partly enclosed in its adultshell and the record of early shell growth is often
separated from the adult part of shell or lost.
I have been fortunate enough to find internal
structural features of the early shell growth in anancyloceratid ammonite collected by H. Tsuda,from the Lower Cretaceous Choshi Group. From
this observation, I have reached the following
conclusions: i) these ancyloceratid specimens
belong to the genus Karsteniceras, ii) ammonites
may be divided into two groups on the basis of
the position of nepionic siphuncle.
This paper gives a detailed description, including internal structural features of these specimens
which are referred to a new species of the genus
Karsteniceras. The paper also discusses the classification and phylogeny of heteromorph ammo-

Introduction
The early ontogenetic stages of ammonoids
have been studied from the view-point of majortaxonomy and phylogeny, especially at ordinallevel, by several paleontologists (e.g. Drushtchits
and Doguzhayeva, 1974, 1981; Drushtchits et al.,1977a, b; Mikhailova, 1974, 1982; Tanabe et al.,
1979; Birkelund, 1981; Ohtsuka, 1986). Accordingly, it would appear that the evidence provided
by the internal structural features of early shell
growth are useful when there are differing opinions concerning the classification and phylogenyof heteromorph ammonites based on the septal
suture line. These studies, however, were concerned mainly with the development of planispiral ammonites and less so with the heteromorpha. The chief reason may be that the*Received June 27, 1986; revised manuscript accepted
October 25, 1987; read June 19, 1983 at Utsunomiya
University.

346

850. Early shell morphology of Karstenieeras

nites at supra-superfamily level on the basis ofobserved internal shell structure and previously
reported data by other workers.
At Choshi, the east end of the Kwanto dis.
trict, the Cretaceous outcrops occur over a small
area along the coastline facing the Pacific Ocean.
According to Obata and Matsukawa (1982), thesuccession can be subdivided lithologically into
five units, named the Ashikajima, Kimigahama,Inubouzaki, Toriakeura and Nagasakihana Formations in ascending order. The species to be
described in this paper was obtained from calcareous concretions in the mudstone of the
middle part of the Kimigahama Formation,
where it is associated with Crioeeratites (Emericieeras) emerici Leveille, Oleostephanus (Neoastieria) eadoeeroides (Karakasch), Barremites(B.) diffieilis (d'Orbigny), Holeodiseus sp. andother species. Thus, the ammonite fauna of theKimigahama Formation shows a close affinity
to that from the Tethyan realm, e.g. the stratotype of the Lower Barremian in France (Busnardo, 1965) and the Barremian of the Sably
Mine in the Crimea, Russia (Karakasch, 1907).
Accordingly, the Kimigahama Formation can be
assigned to the Lower Barremian.
I thank Drs. Ikuwo Obata (National Science
Museum, Tokyo), J. P. Thieuloy (Universite deGrenoble), J. Wiedmann (Universitiit Tilbingen),and H. G. Owen [British Museum (Natural
History)] for their critical reading of the manuscript. I am also indebted to Drs. Kazushige
Tanabe (University of Tokyo), and Masao Futakarni (Kunitachi Senior High School, Tokyo) for
providing fruitful discussion on certain problems.
Thanks are extended to Messrs. Hiroji Tsuda andTadashi Asada for their kind help in collecting
the fossils described herein. The study was
fmancially supported in part by the Science
Research Fund of the Japanese Ministry of
Education, Science and Culture (Monbusho)(Takayanagi, no. 334043 for Cooperative Research in 1978-1980; Obata, no. 56340041 for
Cooperative Research in 1981-1982; Matsukawa, no. 56740335 in 1981 and no. 61740463
in 1986).

347

Depository
The specimens with the prefix NSM are preserved in the Department of Paleontology,
National Science Museum, Tokyo.

Systematic description
Order Ammonoidea Zittel, 1884
Suborder Ancyloceratina Wiedmann, 1960
Superfamily Ancylocerataceae Meek, 1876
Family Ancyloceratidae Meek, 1876
Subfamily Ancyloceratinae Meek, 1876
Two opinions, by Casey (1960) and Wiedmann (1973), have been presented concerning
the classification of the superfamily Ancyloceratinae. Casey (1960, p. 19) stated that theAncyloceratinae (s.s.) consists of the ponderous
heteromorphs of the Aptian genera, i.e. Aneyloeeras, Tropaeum, Australieeras, Epaneyloeeras,
Ammonitoeeras and Lithaneylus. Wiedmann(1973) mentioned that Ancyloceratinae includes
Valanginian to Barremian micromorphs which
are called leptoceratids, i. e. Eoerioeeratites,
Menuthiocrioeeras, Karstenieeras and Hamulinites. Certainly, the evolutionary trend demonstrated by progression from ancyloceratid tocrioceratid coiling about ponderous heteromorphs of the Aptian Lower Greensand (Casey,1960) is different from that of leptoceratids
which does not show the tendency toward coiling. So, the leptoceratids are probably attached
to other subfamily with the exception of Ancyloceratinae, if Ancyloceratinae is defined as that
including only those ponderous heteromorphsof the Aptian genera. It is suggested that these
leptoceratids are grouped within the Subfamily
Leptoceratoideinae (Thieuloy, 1966), because
one of the Barremian leptoceratids described as
Leptoeeratoides by Thieuloy (1966) or by
Va~i(5ek (1972) is distinguished from other leptoceratids in having constrictions in the adult stage.
The constriction is, indeed, one of the criteria
fot classification at superfamily level as exemplified by Desmocerataceae. Leptoceratoidinae

Masaki MATSUKAWA

348(Thieuloy, 1966), however, was synonymouswith the Ancyloceratinae by Wiedmann (1973).
Accordingly, reexamination of the criteria forclassification at subfamily level concerning leptoceratids is necessary. As this is not an appropriate
place to discuss the criteria for classification atsuperfamily level concerning leptoceratids, I tentatively follow the lumping scheme of Wiedmann(1973).
Genus Karsteniceras Royo y Gomez, 1945

Type species: Ancyloceras beyrichii Karsten,
1858.

Generic characters: Whorls of small-size withthin shell and septal walls, coiled crioceraticone
or cyrtocone with open spire followed by aslightly curved shaft and hook. The initial onehalf to two whorls are closely coiled, followed
by loose coiling in a single plane. The adult shellshows nearly flat sides ornamented by strong
simple ribs which are interrupted along thesiphonal line terminating either in ventro-Iateral
tubercles or the rib may be merely slightly
effaced, possessing no ventro-Iateral tubercles,in the middle growth stage. The final portionof the body chamber is covered with numerous
lirae. The suture is ELUI, with slightly indented
trifid lobes.
Discussion: This genus was separated by Royoy Gomez (1945) from the genus Ancyloceras, on
the basis of having crioceraticone shells with nontuberculate ribs, and a Worthoceras-like saddle inthe suture-line. Some specimens which can be
assigned to Karsteniceras, collected from theBarremian Kimigahama Formation in Japan, haveboth of these characters, crioceraticone coilingand non-tuberculate ribs. In these specimens,
however, the characters are merely observable atonly the part of ontogeny described below as thelatter part of the third phase of shell growth.
Tuberculate ribs are recognizable on these specimens from the Kimigahama Formation at another ontogenetic phase. From the above characters, it may be inferred that Karsteniceras has avariable morphology throughout its ontogeny, aview held also by Dr. J. Wiedmann (personalcommunication, November 1985). The ontogenetic description, however, is probably notsatisfied within the description of the genus
Karsteniceras by Royo y Gome (1945).
The leptoceratid heteromorph ammonites,
which have been described either as Leptocerasor leptoceras-like ammonites, form two groups,
one ranging from the Berriasian to Valanginianand the other being restricted to the Barremian.
These two groups are interpreted as separate
subfamilies on the basis of their stratigraphic
interruption at Hauterivian, although they bothshow resemblances to each other (e.g. Thieuloy,
1966; Wiedmann, 1973). According to Wiedmann (1973), the former group, which ranged
from the Berriasian to Valanginian, consists ofthe genus Leptoceras only and is attached tothe subfamily Protancyloceratinae encompassing
such genera as Protancyloceras, Cochlocrioceras,
Vinalesites and Leptoceras. The latter groupoccurring in the Valanginian to Barremian isgrouped in the Ancyloceratinae including Eocrioceratites, Menuthiocrioceras, Karsteniceras andHamulinites.
The classification of leptoceratids based on
ontogenetic characters is judged as follows:
Karsteniceras (generic characters are described
as above) is closely allied to Leptoceras(Thieuloy, 1966, p. 287) from the Berriasianof Switzerland and southern France in its cyrtocone or criocone shell which shows, initially,normal coiling followed by a smooth shaft andlater cyrtocone coiling ornamented by ribbing.
These two genera can be distinguished, however,from each other by the presence in Karstenicerasof a ventral groove and distinct ventro-Iateral
tubercles in the middle growth stage and numerous lirae in the late growth stage.
The Barremian leptoceratids included inAncyloceratinae have been reduced in number
to two genera by Wiedmann (1973) based on
the coiling form. These are Karsteniceras Royoy Gomez, 1945 (=Veleziceras Wright, 1957 pro
Orbigllyiceras Royo y Gomez, 1945; =Leptocera to ides Thieuloy, 1966), which is crioceraticone, and Hamulinites Paquier, 1900 (=Eoleptoceras, Wrightites and Tzankoviceras Manolov,

850. tarly shelll11orphology of Karst ellic eras
1962) which is an ancyloceraticone. [t is possible, however, that the characters of surface
ornamentation are useful in the classification
at generic level. For example, Karsteniceras as
described above from Japanese material iscapable of being separated from Karsteniceras,
as defined by Royo y Gomez (1945), becaue thegeneric characters described by him are alreadypresent in the young stage. This feature of theJapanese material may merit a new name-in consequence. Leptoceratoides (Thieuloy, 1966),
such as the species described by Va~i~ek as
Leptoceratoides PUI11i!us (Uhlig) (1972, p. 54,
pI. 4, fig. 5) and L. subtilis (Uhlig) (1972, p. 54,
pI. 7, fig. 4, text-fig. 16), is distinguished from
Karsteniceras (Royo y Gomez, 1945) in having
constrictions in the adult stage.
Karsteniceras differs from the Barremiangenus Eoleptoceras described by Manolov (1962,
p. 532-533) from northern Bulgaria, which was
included in the genus Hamulinites by Wiedmann(I 973), in its style of coiling and ornamentation.
The coiling in the former is crioceraticone or
cyrtocone, but in the latter it is ancyloceraticone. In Eoleptoceras, the ribs pass over theventer without interruption at all growth stages.
This feature is only seen in Karsteniceras in thelater growth stage. The ventral groove and stout
ventro-Iateral tubercles on the middle stage of
growth in Karsteniceras are not developed in

Eoleptoceras.
Leptoceras, Eo leptoceras and Karsteniceras
are comparable in the configuration of the coiling in their initial one-half to two whorls and intheir slightly curved smooth shafts, and in theirpossession, suturally, of trifid lobes. These features are interpreted as indicating the phylogenetic affinity of these genera and that they
have a common ancestor as suggested by Wiedmann (1973).
The Barremian leptoceratids present diversiform coiling, ribbing and tuberculation. For
instance, Karsteniceras is characterized bycrioceraticone, interrupted ribbing with ventrolateral tubercles and link-like ribbing across theventer without tubercles in the middle growthstage. On the other hand, Eoleptoceras is char-349

acterized by ancyloceraticone coiling and linklike ribbing across the venter without tubercles.
These same features in both of the above genera
are observable in the Berriasian protancyloceratids as well as the Barremian leptoceratids.
Hil11antoceras for example is distinguished byits crioceraticone coiling, link-like ribbing acrossthe venter without tubercles and constrictions
with tubercles, whereas Leptoceras is characterized by cyrtocone or criocone coiling, link-likeribbing across the venter without tubercles.
Characteristic features of Protancyloceras are
cyrtocone and interrupted ribbing across theventer, whereas Vinalesites is typified by ancyloceraticone coiling and link-like ribbing acrossthe venter. The development of these similarmorphological characteristics in both the earlier
and later groups of leptoceratids suggests thatthese two groups adapted to their surrroundings
by using the same morphological strategy.

Karsteniceras obatai, sp. nov.
rigures 1, 2, 3-1-4, 4
1926. Ancy/oceras ? sp. Yabc and Shimizu, p. 17, pI.
15, figs. 12, 13.

Material: NSM-PM 9589, holotype; and NSMPM 9590, paratype; both collected by H. Tsuda.
These specimens were collected from loc. 7309.
Other para types were collected as follows: NSMPM 9591 collected by H. Tsuda, from loc. 7403;
NSM-PM 9592, and NSM-PM 9593 collected by
T. Asada from loc. 7433. All material was collected from the middle part of the Kimigahama
Formation at Isejigaura, Choshi City, Chiba
Prefecture. For descriptions of the localities
yielding these specimens, see Obata et al. (1975)
and Obata and Matsukawa (1982).
Specific diagnosis: Shell of small size, coilingcyrtocone being about 14 mm in maximum diameter of loose spire. Ornament of young shellis smooth, middle portion is ornamented by ribbing and the later portion is covered with numerous lirae. The ribs are rectiradiate, regularly
arranged, elevated, slender, and somewhat
sharpened at the top. The interspaces of ribs areMasaki MATSUKAWA

350

nepion ieeons t r iet ion

1mm
Figure 1. The early stage of Karsteniceras obatai Matsukawa. (a) Th e early part of NSM-PM 9590. (b)Drawing of a median section of the same specimen to show the position of the siphuncJe and septa.

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Figure 2. Karsteniceras obatai Matsukawa.
Diagramatic sket ch of NSM-PM 9590 (a) and 9589 (b, c, d), sho wing th e mode of coiling and ornamentation(a, b), whorl section (c) and suture (d) in its early ontogeny.

twice or thrice as broad as the ribs themselves.
Ontogenetic description: See Table 1.
(i) the first phase (protoconch and threequarters of the first whorl). This phase is divided
into protoconch and nepionic stages. The protoconch is roughly ellipsoidal in shape, being laterally expanded by the succeeding first whorl.
It is 0.32 mm (e.g. NSM-PM 9590) in maximum

diameter. A clear nepionic constriction occupies
323° (e.g. NSM-PM 9590) of the total rotation
angle from the axis of coiling. The nepionic sizeis 0.61 mm (e.g. NSM-PM 9590). Initially , thesiphuncle is located at the central part of thenepionic whorl but then shifts its position to
the ventral side rapidly as the shell grows. The
septa are ado rally convex and almost regularly

850. Early shell morphology of Karsteniceras
spaced from each other. The characters of thisphase can not be shown clearly in an electron
microscope photograph because the two specimens showing this initial stage are too badly
fractured. Figure l(a) is a photograph taken
under the microscope of the initial whorls of
NSM-PM 9590 with an accompanying explanatory drawing in reconstruction.
(ii) the second phase (the proximal part of
the first whorl and most of the second whorl).
This phase is normally coiled. The diameter ofshell is about 1.7 mm (e.g. NSM-PM 9590), andthe shell is narrowly umbilicate at the early 3.5
phi stage. The umbilicus is shallow with an inclined wall. The whorl section is initially roughly
elliptical, much broader than high in a form ratioof 1.8 (e.g. NSM-PM 9589), but changes to acircular shape during the growth of the second
whorl. The surface is smooth without any ornamentation. The siphuncle is wholly ventral inthis stage. The septa are about 12 in number,adorally convex and regularly spaced. The sutureline at this stage shows a shallowly bipartite
external lobe and lateral lobe.
(iii) the third phase (the proximal part ofthe second whorl to the end of the third whorl).
This phase is characterized by a loose cyrtocone
coil form together with the abrupt appearanceof strong ribbing at an early stage. The diameterof whorl is above ca. 2.00 mm. The whorl section
shifts from a circular shape to an oblong shapewith ventral groove, during the growth of theearly to middle stages in this third whorl. The
ventral groove disappears, however, at the proximal end of the third whorl. In the earliest stageof this phase, the surface is still smooth without
any ornamentation. In the middle stage, stout
sharp ribs with ventro-Iateral tubercles appear,
which are interrupted on the venter. This rib
pattern modifies towards the proximal end
producing ribs which cross the venter without
tubercles. The number of ribs increases to about
13 or 16. The sutural pattern can be expressedby the formula ELUI, and is characterized by atripartite U-shaped umbilical lobe and an asymmetrically bipartite lateral saddle.
(iv) the fourth phase (the fourth whorl). A

351

loose coil form with smooth surface, showing
a polygonal cross section, is characteristic of thisphase. The whorl becomes of equal height andbreadth with a ratio of 1: 1. The surface iscovered with numerous lirae.
Comparison: This new species is allied, in its
coiling characteristics, to Karsteniceras asiaticum(Yabe et Shimizu) which was originally describedfrom the Sanchu Terrane by Yabe and Shimizu(1926, p. 73, pI. 15, fig. 21) as Leptoceras asiaticum and which was revised subsequently by
Wiedmann (1973), but is distinguished mainly
by differences in the ornamentation. In theformer species, the ribs are rectiradiate, somewhat sharpened at the top, and interrupted on
the venter. In K. asiaticum, the ribs are rursiradiate, nearly flat on the outer whorl and without
ventral interruption. The ventro-Iateral tubercles
in the former species are stouter than those in
the latter. These two species are consideredhere to be derived from a single common ancestor. Karsteniceras beyrichii (Karsten), thetype species of the genus, from the Barremianof Colombia (Royo y Gomez, 1945, p. 460461; pI. 71, fig. 1) seems to resemble K. obataiin having crioceratid coiling and a ventral groove.
But K. beyrichii is distinguished from the latterby possessing link-like ribbing across the venterand narrow interspaces between ribs without
ventro-Iateral tubercles. K. beyrichii is also similar to Leptoceratoides pumilum (Uhlig) (Va~i~ek,
1972, p. 54, pI. 4, fig. 5) from Silesia (Poland)in showing crioceraticone coiling and a smooth
initial whorl. L. pumilum, however, shows shallow constrictions which are absent in Karsteniceras. Furthermore, the ribs are rectiradiate in
the former, whereas prorusiradiate in the latter.
Yet, if the classification of Barremian leptoceratids is based on Wiedmann (1973), Leptoceratoides would be synonymous with Karstelliceras.
Occurrence: Loc. 7309, a calcareous concretion contained in the mudstone bed at lsejigaura. In addition to the new species, Crioceratites(Emericiceras) emerici LveilIe and Lissollia spp.
occur in the same concretion.
Loc. 7403, a calcareous concretion included

352

Masaki MATSUKA WA

850. Early shell morphology of Karsteniceras
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AIIBWJONi~- Figure 3. Karsteniceras obatai, sp. nov. from the middle part of the Kimigahama Formation, Lower
Barremian. 1. NSM-PM 9591, paratype from lac. 7403 (H. Tsuda coll.). Lateral (a), front (b) and ventral (c)views, x3.0. 2. NSM-PM 9593, paratype from lac. 7433 (H. Tsuda call.). Ventral (a), front (b) and lateral (c)views, x3.0. 3. NSM-PM 9589, holotype from lac. 7309 (H. Tsuda call.). Ventral (a), lateral (b) and front (c)views, x6.0. 4. NSM-PM 9590, paratype from lac. 7309 (H. Tsuda coll.). Lateral (a, b), x6.0.

354

Masaki MATSUKA WA

in the mudstone at Isejigaura. In addition to thisspecies, Hypophylloceras sp., Eotetragonites sp.,

Crioceratites (Emericiceras) emerici Leveille,
Acrioceras? sp., Olcostephanus (Neoastieria)
cadoceroides (Karakasch), Lissonia sp., Neocomites? sp., Barremites (Barremites) difficilis(d'Orbigny), Barremites (Raspailiceras) cassida(Raspail), Barremites (Barremites) sp., Holcodiscus sp. also occur at the same horizon inthis locality. These calcareous concretions also
include many fragmented plant fossils.
Loc. 7309 is 350 metres south of Loc. 7403.
The above localities are all in Choshi City,
Chiba Prefecture. They are in the middle part of
the Kimigahama Formation; Lower Barremian.
Discussion
One of the major factors used in the classification of ammonties at the family and superfamily levels is the configuration of the septal
suture line. Opinions concerning the subdivisionsof the family groups of the Cretaceous ammonites, however, have been diverse. For instance,
it is clear from Kullmann and Wiedmann (l970),
Wright (l981) and Mikhailova (l982) that there
is a disagreement concerning the taxonomic
rank and position based on the septal suturalconfiguration and its ontogenetic development.
Especially, this is so in the case of the heteromorph ammonites. Their phylogeny is interpreted to be monophyletic by Kullmann andWiedmann (1970) and Wright (l981), but tobe polyphyletic by Mikhailova (1982). The
monophyletic phylogeny of the heteromorphs
is derived from the fact that the Ancyloceratina,
as a suborder, shows a consistent ELUI formulain their sutural pattern throughout their growthstage. On the other hand, the concept of a polyphyletic phylogeny is based on the view thatthe heteromorph ammonites are made up of two
types, one having bifid and the other trifid lateral and umbilical lobes. The former is shownby the Turrilitaceae and Scaphitaceae, which
therefore have something in common with
Lytoceratida. The latter is shown in the Ancylocerataceae, which therefore has something incommon with Arnmonitida. These two contrasting opinions on the phylogeny are consideredhere to be incapable of reconciliation because
each stand point is fundamentally dissimilar.
The internal structural features of early shell
growth is useful for the subdivision at orderlevel in the planispiral ammonites (e.g. Tanabe
et al., 1979). In the case of the heteromorphammonites, examples showing the internal shellstructural features of early shell growth are notalways reported in publications, because therecord of the early shell growth is not always
preserved intact with the adult shell, and may be
broken-off and separated. Table 2 gives thetabulation of the internal shell structural featuresof early shell growth including protoconch size,
spiral length of ammo nit ella and position of
siphuncle based on the description by Branco(1879-1880), Smith (l901), Drushtchits et al.
(l977b), Birkelund (l981), Drushtchits andDoguzhayeva (1981), Doguzhayeva and Mikhailova (l982) and this study. In Table 2, thosegenera which were discussed by these authors
are assigned to respective superfamilies byadopting the opinion of Wright (l981). The
protoconch size shows the following maximum
diameter: Ptychoceras and Karsteniceras is about
0.3 mm, Hypoturrilites, Deshayesites and Luppovia are some 0.4 and 0.5 mm. The spirallength of the ammonitella is as follows: Discoscaphites and Luppovia are about 300 0 ,Ptychoceras is some 3100 , and Karsteniceras
and Baculites are approximately 320 0 and
3400 , respectively. The siphuncle in these genera
occupies a ventral or central position: It is ventral in Discoscaphites, Deshayesites, Ammonitoceras, Leptoceras and Karsteniceras, whereas
it is central in Luppovia. In Baculites and Ptychoceras, the position of siphuncle is central
throughout the major part of the nepionicstage, but shifts to a ventral position at theend of this stage. From these observations,admittedly the data are rather poor, the present
author concludes that the protoconch size may
be small in Ptychoceras, middle size in Karsteniceras, and large in Hypoturrilites, Deshayesites
and Luppovia. The spiral length of the ammo-Table 2. Table showing the diagnostic characters in the early growth-stages of previously described genera and Karsteniceras.
Internal characters of nepionic stage

I

Superfamily

Genus

Abnormally coiled
stage

SutureI

Normally coil ed
sta,eeProtoconch

I

,

!

! Baei-tZites
Turrili taceae

f2

II

I

!

I

: Pr:ychoeePQs!3 H;

ScaphitaceaeI••.

ypoturn{"t.tes j!4DisaosaaPhites
i5
i Deshauesites!
..
-

i Deshayesitaceae

I

E LUI
(bifid lateral lobe)Istraight shaft

E LUI(E,L and U are bifid)I
two
I straightparall el shaft

E LUI

helical coiling2,..

- 2.511"I,

unkno"'n

345 0

2,..

! 0.28-0.29 I!

311 0

I

I ELU1 ..... ELP, P2 P3UvUd 1

normally flatside\d th coi 1 ed hookI

all stagetightly planispiral

I ELU2?I ..... ELU2?U3?U' ?1
I

unknown
4,..

IAncylocerataceae

18
Leptoceras'9... ~

I

_

.

"-0

.~_l"Sve""Lae. --1: Smith(1901),

are trifid)

I

2,..

I 0.39-0.40 !
I unknown iI

all stage

1(L,U and

0.43!
I unknown
I,,7, Luppovic.

!

in a planispiral

Position of

,

I

!1

I

I Spiral length

unknown299

0

I center ~ venter l e;;~II, center ~ vent.er 1
~
...
I
~
i

I

I

unknown

unknownI
I,

venterIloosely coilingin a planispiral2,..

ca. 0.5

300 0

centerE LUI(trifid)loosely coilingin a planispiral3.5,.. • 4,..

unknown

unknown

venterE LUI(trifid)loosely coili~gin a planisplral

3.5,.. _ 4,..

2,3,6: Drushtchits et al.(1977),

I

0~
~

~

....~

~
;:;.
~

~

4: Birkelund(1981),

8: Branco(1879-1880),~

venterventerE LUI(trifid)

7: Doguzhayeva &Mikhailova(1981),

~

::::
::;
5
-ti
,I <:);:;--

i

unknm·:n

I

I

0.3:

323 0

venter

'"5: Drushtchits & Dogu:hayeva(1981),

9: This study

Superfamily: adapted from Wright(1981)

'"

Ul
Ul

356

Masaki MATSUKA WA

nitella is small in Discoscapllites and L uppo via,
median in Ptycl!oceras, and large in Karsteniceras
and Baclilites. At the least, one can assert thatthe siphuncle occupies the ventral position in
the Deshayesitaceae, Scaphitaceae and Ancylocerataceae with the exception of Luppovia, andthe central position in the Turrilitaceae andLllppovia. The relationship in these ammonites
between the siphuncular position and planispiralcoiling tends to confirm the following conclusions. Some ammonites with a ventrally positioned siphuncle, except for Ammonitoceras,
have more tightly coiled whorl possessing of one
and three quarters to two coiling, whereas thegroup having a centrally positioned siphuncle
unties its whorl at about a coiling. Whatever
happens to be the case, the position of siphuncle
is considered here to show support for the
Wright (I 981) subdivision of the superfamily
based on the suture, except in the case of thegenus Luppovia. This view is different from
Mikhailova (1982). Luppovia possessing a central
siphuncle may be taken as a group which attempted to improve its siphuncle position in themanner as that observed among the primitive
cephalopods which varied their siphuncle at aventer, central or dorsal position. To our regret,any standard criteria for subdivision of thesuperfamily is considered to be not detectedfrom these data.
In the planispiral coiled ammonites, the position of the siphuncle is observed in numerous
species, and can be seen to be different at somesuperfamily and suborder levels. For example,
the Phylloceratina, consisting of Phyllocerataceae
and Ammonitina, of Acanthocerataceae, Desmocerataceae, Hoplitaceae, Haplocerataceae andPerisphinctaceae, possess a centrally positioned
siphuncle in the nepionic stage, and both the
Lytoceratina of Tetragonitaceae and Lytocerataceae has a ventrally positioned one (Obata
and Matsukawa, 1979; Tanabe etal., 1979,1981;
Drushtchits and Doguzhayeva, 1981). Thus, theposition of siphuncle is variable in both theheteromorph and planispiral ammonites. Ammonites may be divided into two groups on theposition of nepionic siphuncle. The first groupwith an initial siphuncle placed in a central posi-'
tion consists of the Phyllocerataceae, Acanthocerataceae, Desmocerataceae, Hoplitaceae, Perisphinctaceae and Turrilitaceae (part). The
second group with an initial siphuncle in theventral position consists of the Tetragonitaceae,
Lytocerataceae, Deshayesitaceae, Scaphitaceae,
Ancylocerataceae (part) and Turrilitaceae (part).
The initial siphuncular positions are consideredhere to be useful, therefore, in the determination of phylogeny in heteromorph ammonites.
From the view point of the siphuncle position,
it is possible to conclude that the heteromorphammonites are derived from two main stocks.
Ancylocerataceae, Deshayesitaceae, Scaphitaceae
and turrilitaceans composed of Diplomoceratidae
and Nostoceratidae are derived either from
Tetragonitaceae or Lytocerataceae, while turrilitaceans composed of Baculitidae and Ptychoceratidae originated either from Haplocerataceae
or Perisphinctaceae (Figure 4). Furthermore, on
the basis of tiny protoconch size represented in
the Ptychoceratidae and some other families inAmmonitina, such as Desmoceratidae, which are
the smallest in the heteromorph or planispiralammonites respectively, it may be warrantable tosuggest that they originated from a common
stock.
Concluding rematks
The ancyloceratid ammonites from the
Choshi Group described here represent a new
species of Karsteniceras of early Barremian age
in Japan. This species, named Karstelliceras
obatai Matsukawa, sp. nov., is allied to Karsteniceras asiaticum (Yabe et Shimizu) also of early
Barremian in age, from the Sanchu Terrane inJapan, in its coiling and the whorl section withventral groove on the middle stage shell. It
differs from K. asiaticum, however, in possessing stout ventro-Iateral tubercles on the ribs.
Some features of the internal shell structurein the nepionic stage in the new species areobservable. One of the notable characters isthat the siphuncle occupies the ventral position
from the early growth stage.

850. Early shell morphology of Karsteniceras

Cretaceous
Early
Late

J u r.

/.J (:'~.~~'>~
J,'5''.:,' ...

;(0 ),'i) ~.'"r:~,.'I','--':',~J,:.\.

:':~"" -. 1 ~ , ]I

Oeshayesi taceae

, '

Tert.

-

9'~f'
.~,

Tetragonitaceae
Ly tocerataceae
Ancylocerataceae

357

~'")"

3

I t.

\\

Scaphitaceae,I'----...l..-..
_ _ _ _ __

2

I

"
iI: I
L~ostoc.ratida. L~'{fftJ'IM
L ~i£lomoc.ratida.~-1--- Turrilitaceae

I

~

I

-

-:~a~~d-a;-:-- - - -.~, ~'; PtYChoc.r~;i~a.
.

)1

•

~

6 "..

Acan thocera taceae

"

I

I
I

:~~\

I
I
I

'I

10~'

Haplocerataceae

hinctaceae (:a~i:: tl~'::~11.r...

Phyllocerataceae

Q_12

1,4,7.8,12:Tanabe et aJ.(1979)

2:This study

3,10.11: Drushtchits & Doguzhayeva(1981)

9:0bata &Matsukawa(1979)

6: Drushtchits et a1.(1977)

5:Smith(1901)

Famiy tree: adapted from Wright (1981)
Figure 4.

Phylogenetic relationships of Cretaceous ammonites on the basis of siphunclc position.

358

Masaki MATSUKA WA

The siphuncle position of heteromorph ammonites in the early growth stage is recognized
to be of two types, ventral or central in position.
These features are compared with those in theplanispiral ammonites: in the Lytoceratina thesiphuncle occupies the ventral position, but inboth the Ammonitina and Phylloceratina, it
takes the central position in extreme youth. Accordingly, the heteromorph ammonites having
the siphuncle in the ventral position are considered to be allied to the Lytoceratina, whereas
those having the siphuncle in central position are
considered to have an origin in the Ammonitina
and/or Phylloceratina, as one possibility. These
interpretations suggest that the current assumed
phylogeny of the heteromorph ammonites ispolyphyletic.
References cited
Birkelund, T. (1981): Ammonoid Shell Structure. In
M. R. House and 1. R. Senior (eds.), Syst. Ass.
Special Vol. 18, "The Ammonoidea", p. 177 -214,
Acad. Press Co.
Branco, N. (1879-1880): Beitrage zur Entwickelungsgeschichite der fossilen Cephalopoden. Palaeontgr.,
vol. 26, no. 1, p. 19-50, pIs. 4-13, vol. 27, no. 2,
p. 17 -80, pIs. 4-13.
Busnardo, R. (1965): Le stratotype du Bam~mien. 1Lithologie et macrofaune. In Colloque sur Ie
Cretace inferieur (Lyon, September 1963). Mem.
B.R.G.M, vol. 34, p. 101-116.
Casey, R. (1960): The Ammonoidea of the Lower
Greensand. Part I. Palaeont. Soc., p. 1-44, pIs.
1-10.
Doguzhayeva, L. and Mikhailova, I. (1982): TIle genus
Luppovia and phylogeny of Cretaceous heteromorph ammonoids. Lethaia, vol. 15, p. 55-65.
Drushtchits, V. V. and Doguzhayeva, L. A. (1974):
Some morphologeneric characteristics of phylloceratids and Iytoceratids (Ammonoidea). Paleonto Jour., vol. 8, no. 1, p. 37-48, pIs. 3,4 (inRussian transl. English).
and - - (1981): Ammonite under the electron
microscope. Internal shell structure and system of
the Mesozoic Phylloceratina, Lytoceratina and 6
genera of the Early Creaceous Ammonitina. Izd.
Mosk. Univ., p. 1-192, pIs. 1-43 (in Russian).
and - - and Lominadze, T. A. (1977a): Internal
structural features of the shell of Middle Callovian
ammonites. Paleont. Zhur., vol. 12, 66, no. 3, p.
19-29, pI. 1 (in Russian).

- - , - - and Mikhailova, I. A. (1977b): The structure of the ammonitella and the direct development of ammonites. Ibid., vol. 12, no. 2, p. 57 -69,
pIs. 5, 6 (in Russian).
Karakasch, N. I. (1907): Le cretace inferieu de la
Crimee et sa faune. Soc. Imp. nat. St. Petersbourg,vol. 32, p. 1-482, pIs. 1-26 (in Russian with
French resume).
Kullmann, J. and Wiedmann, 1. (1970): Significanceof sutures in phylogeny of ammonoidea. Univ.
Kansas Paleont. Contr., Paper 47, p. 1-32.
Manolov, J. R. (1962): New ammonites from theBarremian of northern Bulgaria. Palaeontology,
vol. 5, p. 527-539, pIs. 73-76.
Mikhailova, I. A. (1974): Thc relationship between early
Cretaceous and late Cretaceous Hoplitaceae.
Review ot the Bulgarian Geological Society, vol.
35, part 2, 117 -132 (in Russian).
--(1982): The system and phylogeny of the higher
taxa of Cretaceous ammonoids. Paleont. Jour.,vol. 17, no. 2, p. 15-32 (in Russian transl. English).
Obata, I., Hagiwara, S. and Kamiko, S. (1975): Geological age of the Cretaceous Choshi Group. Bull.
Nam. Sci. Mus., ser. C, vol. 1, no. 1, p. 17 -36, pIs.
1-3 (in Japanese with English abstract).
- - and Matsukawa, M. (1979): Ontogeny and variation in Hypacanthoplites subcornuerianus, a Lower
Cretaceous hoplitid ammonite (Lower Cretaceousammonites from the Miyako Group 6). Prof
Saburo KANNO Mem. vol., p. 185-211, pIs. 23,
24.
and - - (1982): Integrated mega- and microfossil biostratigraphy of the Lower Cretaceous
Choshi Group, Japan. In Obata, I., Maiya, S.,
Inoue, Y. and Matsukawa, M., Bull. Natn. Sci. Mus.,
Ser. C, vol. 8, no. 4, p. 147-179, pIs. 1-6.
Ohtsuka, Y. (1986): Early internal shell microstructureof some Mesozoic ammonoidea: implications forhigher taxonomy. Trans. Proc. Palaeont. Japan,
N.S., no. 141,275-288, pis. 45-50.
Orbigny, A. d' (1842): Paleontologie fran~aise 1,
Cephalopodes. p. 1-662, pIs. 1-148, Paris.
Paquier, V. (1900): Recherches geologiques dans Ie
Diois et les Baronnies orientales. Trav. Lab. geol.
Fac. Sc. Univ., vol. 5, p. 149-556, pIs. 1-8.
Royo y Gomez, J. (1945): Fosiles del Baremiense
colombiano. Compl. Estud. Geol. Otic. Colombia,
vol. 6, p. 455-495, pIs. 70-74.
Smith,1. P. (1901): The larval coil of Baculites. Amer.
Naturalist, vol. 35, no. 409, p. 39-49.
Tanabe, K., Obata, I., Fukuda, Y. and Futakami, M.
(1979): Early Shell Growth in some Upper Cretaceous Ammonites and its implications to majortaxonomy. Bull. Natn. Sci. Mus., ser. C, vol. 5,
no. 4, p. 153-176, pIs. 1-6.

850. Early shell morphology of Karsteniceras
and Futakami, M. (1981): Early shellmorphology in some Upper Cretaceous heteromorph ammonites. Trans. Proc. Palaeont. Soc.
Japan, N.S., no. 124, p. 215-234, pis. 35-38.
ThieuJoy, J. P. (1966): Leptoceras berriasiense dumassif de la Grande-Chartreuse. Trav. Lab. Geol.
Grenoble, t. 42, p. 281-295, pis. 1,2.
Vasicek, Z. (1972): Ammonoidea of the Tesfn-Hradiste
Formation (Lower Cretaceous) in the Moravskoslezske Beskydy Mts. Rozpravy Ustrednfho ustavu
goiogickeho, vol. 38, p. 5-103, pis. 1-14.
Wiedmann, J. (1973): Ancyloceratina (Ammonoidea)
at the Jurassic/Cretaceous boundary. In Hal1am(ed.), Atlas of Paleobiogeography, p. 309-316.

""fll~B~*jj~'f)jltfgg Karstenicradlt,

J:V",

359

Elsevir Co.
Wright, C. W. (1957): In Moore, R. C. (ed r ), Treatiseon Invertebrate Paleontology, Part L, Mollusca,
Cephalopoda, Ammonoidea, Ll-L490, Geol. Soc.
Amer. & Univ. Kansas Press.
-(1981): Cretaceous Ammonoidea. In M. R. House
and J. R. Senior (eds.), Syst. Ass. Special vol. 18,"The Ammonoidea", p. 157-174, Acad. Press Co.
Yabe, H. and Shimizu, S. (1926): Cretaceous mol1uscafrom the Sanchu Graben in the Kanto Mountainlands, Japan. In Yabe, H., Nagao, T. and Shimizu,
S. Sci. Rep. Tohoku Imp. Un iv. , 2nd Ser. vol. 9,
no.2,~33-76,pIL 12-15.

(7;, ~ 0 k '7 A~li7;'.f:-t- 1 ") ~):mWlml:l7)jf~~H.:rI7)B~*,c¥t;-m-~7;'.f:-t-1 "17)*f.Jc!~ c "?-CI7)~rt: £j~'ft1!l.t!l7)/q/ ~ 7;'~'ri*JllI;/J'

t,ggtl:lLt.::7;,~ok'7AH,~},g;TQ¥t;-m-~7/.f:-t-1" If][~~5]JjL-C Karstenicerasobatai C fr;~, $/fflfl c L -C~[.~i,\( L t.::o .:r L -C, .:r l7)Jjj(;ffMWlI7)*,il7)l"J$t~Jl!t c 1Ct,~ f4Ht'"~.h. -Cl" Q.-m-~7/.f:-t-1rl7).:r.h.t~h~-C, .HJ:Q.*I7)H~I7)~.c*f.Jc~~.L~o':17)$/fflfll;j:, Karstenicerasasiaticum (YabeetShimizul '~~f1f!ATQo L;/J'L, .:r17)Jjj(;ffl=Jl
MI7)H~I7).~.$I7)~I7)~~~~Q~~.~~~~t~,:c,• • ~t~,:c~gW~.h.Qo~.~,Jjj(;ff.M~ .~(l7)m.~~-I7)*~~t,.~L~tl7)c~~t,.h.Qo~.~.*I7)-~~Jjj(;ffMWl.I7)I"J$.Jl!t~~.~hQo.:rl7)i~ • • • • I7)~~~~§TQc,.-m-~7/.f:-t-1,,"ct,.:rh;/J{n!ill~1R~'~~Qtl7)cl=Jl~'~fft~TQtl7)c=-~17)?17"~

g~~~Qo ':h~, ~-m-~7/.f:-t-1"~.:rI7)=-~17)?17'~t,~Ql7)c~.~,.f:-t-1 ";/J{~*f.JcL·~Q cT Q-~I7)~~m~ff,L -C1,'Q c~'~ t,hQ o• • ~7/~JlI~mErrata
No. 146, 830. YAJIMA, Michiko: Pleistocene Ostracoda from the Atsumi Peninsula, central
Japan
page

column

49
51
53
53
53
53
54
56
64
74
53
69
64

left
left
left
right
right
right
left
left
right
left
Fig. 4
Fig. 9
right

line

read

for

from bottom
the Takamatsu
the the Takamatsufrom bottom
autochthonous
authochthonousbisanellsis
bisanensi
from bottonbisanensis
bisanensi
3
11
2606
2605
12
2606
2605
from
form
9 from botton
Bicornuclztlzere
Bicornucytlzere
2CACa
15 from botton
10
1108
118
4 (Explanation)
200m
20 cm
Innver1 (Explanation)
Inner
between 16 and 17 lines the following synonymy is inserted.
5
4
4

Coquimba poga Hu, 1986, p. 122, 124, pI. 3, figs. 13, 16 -18, 21, 22, text-fig. 4a.

11

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1988-1f. 6 }=j 25 B - 26 B

1988-1f. 4 }=j 10 B

~ij{Ej3~9G : =;=113 J4tJ¥-1:~JtJiOR%;~2-4-16

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Transactions and Proceedings of the PalaeontologicalSociety of Japan
December 30, 1987

New Series No . 148

CONTENTS
TRANSACTIONS
840. TSUKAGOSHI, Akira and IKEYA, Noriyuki: The Ostracod genus Cythere O.F . Milller,
1785 and its species . . .. . . .... . . . .. . .. . ... • . . . . . . . : .... . . . . . ... 197
841. NlKO, Shuji and HAMADA, Takashi:

Adnatoceras from Middle Carboniferous of

the Ichinotani Formation, Fukuji district, cental Japan .. . .... . . . . .. . . . . . . . 223
842. YOSHIDA, Yasushi, OKIMURA, Yuji and KATO, Makoto : Early Carboniferous corals
from the Omi Limestone, central Japan .... . . . . . . . . . . . . . . ... . . . . ..... 228
843. MAJIMA, Ryuichi and TAKAHASHI , Hirokazu : Miocene molluscs from the Kozono
Formation, Saitama Prefecture, central Japan .. . . .. ... . . . . . . . . . . . . . . .. . 246
844. KOJIMA, Satoru and MlZUTANI , Shinjiro : Triassic and Jurassic Radiolaria from the
Nadanhada Range, northeast China .... . .. . . . . . . . . . .. . . . . .. .. ... . . .. 256
845 . TAZAWA , Jun·ichi: Attenuatella (Brachiopoda) from the Upper Permian of northeast Japan and its bipolar distribution . . . . . . . . . . .... . .... . . .... . . . ... . 276
846. MAEDA , Haruyoshi : Taphonomy of ammonites form the Cretaceous Yezo Group in
the Tappu area, northwestern Hokkaido , Japan . ..... .. . . .. . . .. . . . . . . . . . 285
847. KONDO , Yasuo : Burrowing depth of in faunal bivalves - Observation of living species
and its relation to shell morphology . .. .. .... . .... . ... . . . . . . . . . . . . . .. 306
848. KOZAl , Takeshi : Cretaceous Caestocorbula (Bivalvia) from Japan ..... . . . . . . . . 324
849 . NIKO, Shuji, NISHIDA, Tamio and KYUMA, Yuko:

Middle Carboniferou s Ortho-

cerataceae and Pseudorthocerataceae (Mollusca: Cephalopoda) from the Akiyoshi
Limestone, Yamaguchi Prefecture (Molluscan paleontology of the Akiyoshi Limestone Group-VIII) . . . ..... . . . . . . . .. . .. .. . . . .. .. . .. . ... . . . . . . . . . 335
850. MATSUKAWA , Masaki: Early shell morphology of Karsteniceras (Ancyloceratid)
from the Lower Cretaceous Choshi Group, Japan and its significance to the phylogeny of Cretaceous heteromorph ammonites ..... . .. . . ..... . . ..... . ... 346