ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New Series

No.

167

Palaeontological Society of Japan
September 30, 1992

Co-Editors

Tsunemasa Saito and Kei Mori

Language Editor

Martin Janal (New York)

Editorial Board
Kunihiro Ishizaki (Tohoku University), Yukio Isozaki (Yamaguchi University), Tomoki Kase
Itaru Koizumi (Hokkaido University), Yasumochi Matoba (Akita
University), Kei Mori (Tohoku University), Hiroshi Noda (University ofTsukuba), Tsunemasa Saito(Tohoku University), Y okichi Takayanagi (Ishinomaki Senshu University), Kazushige Tanabe(University of Tokyo), Yukimitsu Tomida (National Science Museum), Kazuhiko Uemura (National(National Science Museum),

Science Museum)

Officers for 1991-1992
President: Kiyotaka Chinzei
Honorary President: Teiichi Kobayashi
Councillors: Kiyotaka Chinzei, Takashi Hamada, Yoshikazu Hasegawa, Itaru Hayami,
Hiromichi Hirano, Hisayoshi Igo, Noriyuki Ikeya, Junji Itoigawa, Tomoki
Kase, Makoto Kato, Tatsuaki Kimura, Haru Koizumi, Kei Mori, Hiroshi Noda,
Ikuo Obata, Kenshiro Ogasawara, Tomoo Ozawa, Tsunemasa Saito, Yokichi
Takayanagi, Kazushige Tanabe
Members of Standing Committee: Hiromichi Hirano (General Affairs), Tomoki Kase
(Finance), Tsunemasa Saito (Editor in Chief, TPPSJ), Kei Mori (Co-Editor, TPPSJ),
N oriyuki Ikeya (Planning), Hiroshi N oda (Membership; Co-Editor, Special Papers),
Kazushige Tanabe (Foreign Affairs), Itaru Hayami (Editor, "Fossils"), Toshiyuki
Yamaguchi (Associate Editor, "Fossils"), Juichi Yanagida (Co-Editor, Special Papers),
Tatsuaki Kimura (Friends of Fossils)
Secretaries: Akito Asai, Tatsuo Oji (General Affairs), Masanori Shimamoto (Editorial of
TPPSJ), Hiroshi Kitazato (Planning), Katsuo Sashida (Membership), Yukimitsu
Tomida (Foreign Affairs), Katsumi Abe (Editorial of "Fossils"), Takeshi Ishibashi(Editorial of Special Papers), Tamiko Ohana (Friends of Fossils)
Auditor: Kuniteru Matsumaru
The fossil on the cover is Trilophodon sendaicus Matsumoto, an extinct elephant, which
was described from the Pliocene Tatsunokuchi Formation developed in the vicinity of
Sendai, Northeast Honshu, Japan. (lGPS colI. cat no. 87759 (A), length about 18.5 cm)
All communication relating to this journal should be addressed to the

PALAEONTOLOGICAL SOCIETY OF JAPAN
c/o Business Center for Academic Societies,
Honkomagome 5-16-9, Bunkyo-ku, Tokyo 113, Japan

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 167, pp.1165-1179, 15 Figs., September 30,1992

940. FOSSIL NONARTICULATED CORALLINE ALGAE AS DEPTH
INDICATORS FOR THE RYUKYU GROUP*Y ASUFUMI IRYU
Institute of Geology and Paleontology, Tohoku University,
Aobayama, Sendai 980

Abstract. Fossils of nonarticulated coralline algae occur in the coral limestone of the
Pleistocene Ryukyu Group distributed in Yoron, Okierabu, Toku and Kikai Islands. Four
fossil nonarticulated coralline algal assemblages are compared with their Recent coralline
algal depth distribution in the Ryukyu Islands. Each assemblage represents a particulardepth range. Depositional environments inferred from the Pleistocene coralline assemblages accord well with those based on hermatypic corals and benthic foraminifera.
Key words. Nonarticulated coralline algae, depth indicator, species assemblage, Pleistocene, Ryukyu Group.

corallines occur abundantly as crusts in thecoral limestone or as an aggregated form offoraminiferal-algal nodules (rhodoliths)
forming a distinct lithofacies called therhodolith limestone. Heydrich (1900) firststudied these fossil corallines in the Ryukyu
Group and described Lithothamniscum nahaense, an important constituent of the flora.
However, taxonomic works were undertaken
later by Ishij ima (1938, I 942a, 1942b, 1944,1954), who described 16 nonarticulated and
27 articulated coralline algal species.
Minoura (1979a, 1979b) and Minoura andN akamori (1982) investigated a sedimentological aspect of the rhodolith limestone
and Iryu (1984, 1985) revised these results
based on a study of Recent rhodoliths. Sincepaleoenvironmental significance of the fossil
corallines in the coral limestone has not been
examined, however, they have not widely
been used as paleoenvironmental indicators.
In contrast, Noda (1976) and Nakamori(1986) used benthic foraminifers and hermatypic corals as paleoenvironmental indicators, and mapped the distribution of biota
and various sediment types in the reef-

Introduction

Nonarticulated coralline algae (Corallinaceae, Rhodophyta) play an importantframework-building role, together with hermatypic corals, in Tertiary to Recent reef
formations. For example, they may cover
more than 30% of the reef surface in somemodern reefs (Littler, 1973a, 1973b; Iryu andMatsuda, 1988). Intensive ecologic studies
on the nonarticulated corallines in the modern tropical reef environment have been conducted since the 1960's. This enables us tomake use of these organisms for paleoenvironmental interpretation. Studencki (1979)
and Bosence and Pedley (1982) analyzed
depositional environments of algal-related
biofacies mainly based on the coralline morphology, while Mankiewicz (1988) and Jonesand Hunter (1991) used the coralline assemblages as a depth indicator.
The Pleistocene Ryukyu Group, reef complex deposits, consists of limestones andrelated terrigenous sediments. The fossil"Received December 14, 1989; revised manuscript
accepted July 10, 1992
1165

Yasufumi Iryu

1166

1~;;~~===t==l==r::JKyYijUiSiSHif(jU-ZIJ 32'M.

o'~MAGE-JIMA:0 ~~r---+-----~---4----~.*.~---+~30':~~KIKAI-JIMA-,r-----~----~~--~~------~28'

OKIERABU-JIMA: I>~TOKUI-NO-SHIMA
I
0{ ·~YORON-JIMA

n-----i---__}-__~L-._·.·~~~~~.O~KI~NA~W~A~~~H26'
ISHIGAKI-JIMA
I! : ..h~MiYAKO-JIMA• .0:.;1 SHIMOJI-JIMA.

HATERUMA -J I MA~~::~;=====;t;=====t;====~~=====t;=====jj22'

120'

122'

124'

Figure 1.

Map showing locations of the study area.

complex facies at the time of deposition of the
Ryukyu Group.
This paper aims at establishing the usefulness of fossil nonarticulated coralline algae
in a coral limestone facies as depth indicators
for the Ryukyu Group; that is to establish a"coralline bathymeter," in the following
manner. The distribution of living corallines in the reefs around the Ryukyu Islands isreviewed. These data, coupled with thosefrom Guam (Gordon et al., 1976) and
Hawaii (Adey et al., 1982), form a basis toselect depth-indicative species from the fossil
corallines occurring in the Ryukyu Group.
This in turn enables to circumscribe discrete
species assemblages, each of which represents
a particular depth range. Paleobathymetricaccuracy based on the coralline assemblages
will then be tested against those derived fromthe coral communities (Nakamori, 1986) andbenthic foraminiferal assemblages (Noda,
1976).
The taxonomy used for identifying corallines coming under the subfamilies Litho-

126'

128'

130'

132'E

phylloideae and Melobesioideae is that of
Woelkerling (1988), with some later nomenclatural modification, such as disposition of
Titanoderma proposed by Campbell andWoelkerling (1990). However, the extended
generic concept of Spongites (subfamily Mastophoroideae), which encompasses the genera
Porolithon, Hydrolithon, and Pseudolithophyllum sensu Adey (1970) as heterotypicsynonyms of Spongites (Penrose and Woelkerling, 1988), is not adopted and the latter
three genera are conserved.
Living nonarticulated coralline algae
The reef complexes around the Ryukyu
Islands are divided into three basic topographic zones; reef flat, reef slope, and island
shelf. N onarticulated coralline algae are
distributed in all three zones (Figure 2).
Reef Flat

No quantitative investigation on the coralline algae inhabiting the reef flat has been
conducted. The following evidence is avail-940.

Fossil nonarticulated coralline algae as depth indicators

1167

Neogolliolitholl collicumN.
frutescens
Spollgites sp. A
POrolitilO1l ollkodes

P.

sp. A

HydrolitllOll reillboldii
Mastophora rosea
Fosliella farillosa
Plleophyllum sargassii
LitllOpllyllum illsipidumL.
moluccellSe
Mesophyllum erubescellS
M. purpurascells
Lithothamllioll australe
L.
sp. A

Seagrass

Algal Turf!it Sargassllnl....----.

Depth (m):'.~'.,""'.,.:...::::::===:::;:;>==~.....,.-----~

u:

'$a:
~

to

.:

'iii
e
u
'&i
...
a:

.... 0.... 10.

.... 20~::J.... 30

0

...Cl

'0

.... 40

w

'&i
...
a:

.... 50

I-Reef _ _~~I.~ Reef ~ISland _ _
Flat
Slope
Shelf
Figure 2. Schematic diagram showing distribution of nonarticulated coralline algae in reefs around thepresent-day Ryukyu Islands

able on the distribution of coralline algae at
a qualitative level.
(1) Eighteen species coming under nine genera of the nonarticulated coralline algae are
identified (lryu, 1991 a, 1991 b). They are
Neogoniolithon conicum (Dawson) Gordon,
Masaki et Akioka, N. Josliei sensu Matsuda(1989), N. Jrutescens (Foslie) Setchell et
Mason, Spongites sp. A ( = Spongites sp. A in
Iryu and Matsuda (1988», Porolithon onkodes (Heydrich) Foslie, Porolithon sp. A (=Porolithon sp. A in Iryu and Matsuda (1988»,
Hydrolithon reinbofdii (Weber van Bosse andFoslie) Foslie, Mastophora pacifica (Heydrich) Foslie, M. rosea (c. Agardh) Setchell,
Fosliella Jarinosa (Lamx.) Howe, Pneophylfum sargassii (Foslie) Chamberlain, Lithophyllum insipidum Adey, Townsend et Boykins, L. kotschyanum Unger, L. mofuccense(Foslie) Foslie, L. pallescens (Foslie) Foslie(= L. okamurai Foslie), Mesophyllum
erubescens (Foslie) Lemoine, M. mosemor-phum (Foslie) Adey, and M. syrphetodes?
Adey, Townsend et Boykins.
(2) Some species show a wide range in theirdistribution and others are found in a particular habitat. Neogoniolithon conicum, Spongites sp. A, Porolithon onkodes, 'Porolithon sp.
A, Hydrolithon reinbofdii, L. insipidum, andL. mofuccense grow abundantly on well-illuminated rocky substrata and rubble in mostof the reef flat except for near-shore seagrassbed (lryu and Matsuda, 1987). The habitats
of N. Jrutescens, M. rosea and L. pallescens
are very limited: N. Jrutescens is found in
the shore-side-half of the moat, covering
gravels which originated from calcified skeletons, to form open to densely branched algal
nodules; L. pallescens is seen in places
through which strong currents flow such as
the strait of the Kabira Cove (Matsuda,1987); M. rosea occurs in and around theSargassum thicket flourishing on the seawardmargin of the reef crest.

Yasufumi Iryu

1168

SO

"""
0:$!

40

Co!)

30

~

20

'-'
~

«
~
:>

0

u

10

10

DEPTH (m)~ Neogoniolithon conicum

WZI Porolithon onkodes
E2J Hydrolithon reinboldii~ Lithophyllum sp. A_ Other Corallines~ Spongites sp. A
flZJ Porolithon sp. A~ Lithophyllum insipidum
IIIIIIIIIl Mesophyllum purpurascens

Figure 3. Coverage and density (number of thalli/c.a. 3,200 m 2 ) distribution of nonarticulated coral1ine
algae. Data from Iryu and Matsuda (1988).

Reef Slope

Eighteen species coming under seven genera are recognized. They are Neogoniolithon
colli (= Rhizolamellia colli Sheveiko), N.
conicum, N. fosliei, N. fosliei sensu Matsuda(1989), Spongites sp. A, Porolithon onkodes,
Porolithon sp. A, Hydrolithon laeve? (=Hydrolithon sp. in Iryu and Matsuda (1988»,
H. reinboldii, Hydrolithon sp. A, Mastophorapacifica, Lithophyllum insipidum, L. kotschyanum, L. moluccense, Lithophyllum sp. A( = Lithophyllum sp. A in Iryu and Matsuda(1988», Mesophyllum erubescens, M. purpurascens, and M. syrphetodes ?
Iryu and Matsuda (1988) measured thestanding crop of the nonarticulated coralline
algae on well-illuminated flat rocky substrata
in the forereef environment down to 30 m
depth and their results are summarized asfollows (Figure 3). The mean total coverageand density are 33.0% and 5.6 thalli/IOO cm 2 ,respectively, throughout the investigateddepth range. The dominant species are N.
conicum, Spongites sp. A, P. onkodes and L.
insipidum. Neogoniolithon conicum is distributed throughout the observed depth

range, not showing a regular pattern in its
standing crop distribution, and its mean density ranks first of all the species. Spongites
sp. A has the greatest mean coverage and its
standing crop is highest at 15 m depth.
Porolithon onkodes and L. insipidum are mostabundant at 1 m depth, but they decrease
markedly with increasing depth and are
entirely absent below 20 m.
Based on such a depth distribution, three
nonarticulated coralline algal assemblages are
discriminated; Assemblage I, II and III.
Assemblage I is distinguished by abundant P.
onkodes and L. insipidum and its depth
ranges 0-15 m. Assemblage II is characterized by the common to abundant occurrenceof Spongites sp. A. Depth range of Assemblage II is between 15 and 25 m, where P.
onkodes and L. insipidum are scarce down to
20 m and are entirely absent below that.
Assemblage III, observed deeper than 25 m, isdelineated by the common growth of N.
conicum. Spongites sp. A is seldom found,
whereas M. purpurascens with extensive thalliis sporadically distributed in this depth range.
The coralline-algal flora has not been inves-

940.

Fossil nonarticulated coralline algae as depth indicators

tigated at depths from 30 to 50 m.
Island Shelf

Extensive investigations of biota and sediments by such authors as Nohara et al.
(1979), Iryu (1984, 1985), Iryu and Hayasaka(1985), Matsuda and Tomiyama (1988), andTsuji et al. (1989) have revealed that therhodoliths, nodules composed predominantlyof non articulated coralline algae, are distributed commonly on the deep forereef toisland shelf in waters from 50 to 200 m deeparound the Ryukyu Islands. Recently, Matsuda et al. (1992) showed the distribution,
abundance, and composition of rhodoliths
based on 119 grab samples taken around
Okinawa-jima at depths from 50 to 200 m.
The rhodoliths are found from 70 sites in
depths from 50 m to 135 m. The mean coverage of the rhodoliths is about 45 % in thatarea. These rhodoliths are spheroidal, ellipsoidal, or rarely a disclike shape, 5-10 cm (upto 15 cm) in mean diameter, and consist
mainly of thin crustose forms of nonarticulated coralline algae and the encrusting foraminifer Gypsina plana (Carter), both ofwhich are closely superposed to form a moreor less concentric or irregular internal structure. Twenty-eight species of the nonarticulated coralline algae have been identified,N

1169

coming under the genera Spongites,
Hydrolithon, Lithoporella, Lithophyllum,
Mesophyl/um, and Lithothamnion. Of these,
Lithothamnion is the most dominant anddiverse, comprising 11 species. The nonarticulated coralline algae grow commonly,
covering 40 to 50% of the surface of therhodoliths at depths less than 120 m, whereas
G. plana predominates in depths exceeding
120 m.

Fossil non articulated coralline algae
Field Setting

Fossil nonarticulated coralline algae werestudied from the Yoron-jima, Shimohirakawa
and Kamishiro, Sakibaru, and Takigawa
Formations on Yoron-jima, Okierabu-jima,Toku-no-shima, and Kikai-jima, respectively.
There were 14 localities in Yoron-jima, 11 inOkierabu-jima, 10 in Toku-no-shima and 9 in
Kikai-jima (Figures 4,5,6 and 7). Okierabu-jima and Kikai-jima were selected forN+

Okierabu-jima

Yoron-jima+ooFigure 4. Map showing localities of samplingsites and their coralline-algal assemblages (whiteletter in solid circle) in Yoron-jima. Lines drawn inthe map are roads.

2 km

Figure 5. Map showing localities of samplingsites and their coralline-algal assemblages (whiteletter in solid circle) in Okierabu-jima. Lines drawn
in the map are roads.

Yasufumi Iryu

1170
Toku-no-shima

N

Kikai-jima

N

+

+

o

1 km
~

o

Figure 6. Map showing localities of samplingsites and their coralline-algal assemblages (whiteletter in solid circle) in Toku-no-shima. Lines
drawn in the map are roads.

2 km

Figure 7. Map showing localities of samplingsites and their coralline-algal assemblages (whiteletter in solid circle) in Kikai-jima. Lines drawn inthe map are roads.

Table 1. List of fossil nonarticulated coralline algae. Unit of occurrence in the table refers to the percentageof thin sections in which each species was present to the total number of sections examined.

~
Species

NeogolJiolWwIJ fosliei

S. E

Okierabu-jimaKamishiro F.

o ... t\lC'l~... C\lM..,.InCOr--CDOI ........ .,... ........

»»»»»»»

w~~tlHE~~~~~w~

000

O.

Yoron-jima

Voronllma ~'.

N. (osliei SetlSU Matsuda (1989)
Spongites sp. A
Porolit/lOn onkodes
P.

Hydrolit/JOIJ improcerumH.

reinholdii~~eu:fojt'IOPIJYllUm spp.

LlthoporelJa meJobesiaides

Mastophoro pacifica
LithopJzyllum itrslpidum
L. tesellatum
L. sp. B
L.

...

sp.A

spp. (branched form)

Mesop/Jyllum erubescensM.
purpumscens
LltJwtharmJioll australe
L. fimafutlense

L. sp.A
ArchaeoJithothamlJium erythraeum

0
0
0

0
0
000

DO 0
DO

0

•DO ...

DO
0
0
0 0
0
00 000. 00.0000 00000"'00
0
DOD 0 DO
0 0

...

...

0

.......... 0 .....

00'" 0
DO 00

0

0

ODD

0

0

0

DO

0
0'"
00
0
DO
0
0'"
DO
"'0
0

DO
0

000.0000 ......
0

0

DO

0
0

0

Number of sections examined 2114141110121414121330152121
Assemblage BBABACAABCABAC

comparison of paleoenvironments inferredfrom fossil corallines with those based on
fossil corals by Nakamori (1986), and somespecimens were collected from the same outcrops where he examined fossil corals.
Yoron-jima was also investigated for comparison with benthic foraminifers by Noda
(1976). Toku-no-shima was chosen because

...
0

0
DO

DO
0 0
00
0 ... 000
0000000000
00000

DOD

0

DO

............

00000
000
0 "'0'"
0'"0 0000 DO
DO
0
0 DODO'"
0

00

...

DOD

0

...-C\lM..,.lt)<Cr--CCcn ....

1-1-1-1-1-1-1-1-1-1-

0 ...

O.t..OOD...

00000000
DO
DOD
0

...0

0
DO
DO
00

• 00

Takigawa F.

Saklbaru F.

0

0'"
0
0

Klkal.jlma

Toku-no-shima

0

0
00
DO
0
00
0
00
00 ... 000000
0
DO
0000

...

0000

.................
000 DODoa

0000 ...... 00.0
DODD

0

"'0

......

DO"'0 000000"'000 00000
00000 .... 0 ... 0
0
0
0 000
O.

0

NM..,.It)CO,...c:ocn ....

~:::.::::.::~~~:w::~~

00000
0 0

... 0000000000... DO 0 DO

0000000.0
DO 0.0.... 00.0
000 DO00 0
0 0
DO00.0 0 . 4 0
DO
0 DODD

2435

351722 3113 212540 17

171630 1716 21 24 23 21 26

30251823 2022 26 22 21BB

ABACADCAAC

BAABBAABAACCOOBBCBB

fossil corallines occur in the best state ofpreservation among the Ryukyu Islands.
The stratigraphy of these islands has been
discussed by previous works (Yoron-jima,
Noda (1976), Iryu (1986); Okierabu-jima,
Iryu et al. (1992); Toku-no-shima, Iryu andYamada (1991); and Kikai-jima, Nakamori(1986)).

940.

Fossil nonarticulated coralline algae as depth indicators

moluccense, L. tesellatum Lemoine, Mesophyllum erubescens, M. purpurascens, Lithothamnion australe Foslie, L. funafutiense(Foslie) Foslie, and Archaeolithothamnium
erythraeum (Rothpletz) Foslie. It can beconcluded that the coral1ine-algal floral composition of the Ryukyu Group is almost thesame as that of modern Indo-Pacific reef
regions. There are some differences in thecoral1ine-algal species composition between
Recent and Pleistocene floras in the Ryukyu
Islands. Neogoniolithon conicum, for example, is very abundant in the present-day
Ryukyu Islands, whereas it is not found fromthe Pleistocene Ryukyu Group. On theother hand, N. fosliei, which has a very low
level of standing crop in the modern reefs, israther common in the Pleistocene.
Hydrolithon sp. A and Lithophyllum sp. B
are new to science and wil1 be described
elsewhere. Hydrolithon improcerum (Foslie)
Foslie has been reported only from the Atlantic Ocean, and this is the first discovery of

Floristic Characteristics

Some 955 thin sections were examined inthis study. Eighteen species coming under
11 genera of fossil nonarticulated coral1ine
algae whose thal1i appear to be in situ werecounted and listed (Table I). This list does
not include the coral1ines which seem to havegrown in a cryptic, shaded environment as
judged from their growth directions; such
cryptic flora is beyond the scope of my investigation of the modern coral1ine-algal distribution and thus is of no use for establishinga "coral1ine bathymeter". Fragments of 2
branched (N. frutescens and L. moluccense)and 1 leafy (N. colli) species are also recognized, although not counted and listed.
Among those species known from the Ryukyu
Group, the fol1owing species have been reported from reefs in the present-day Indo-Pacificregion: Neogoniolithon colli, N. fosliei, Poro-lithon onkodes, Hydrolithon reinboldii, Lithoporella melobesioides (Foslie) Foslie, Mastophora pacifica, Lithophyllum insipidum, L.
.cb"""

~

~

~

~
c;:.

~r-,.,;

Legend

--

--,

~

~

~~

~~

~

g

fIICi

,~

Wl 11 i?>

1171

'--'

.....~0,

-:...

\ Dt

~ ~

~
>

o
,

I

!

1

I

5 mm
,

Figure 8.
Sketch of a typical example of Assemblage A in E6 (Okierabu-jima). a: Neogoniolithon
fosliei; b: Spongites sp. A; C: Porolithon onkodes; d: Porolithon ? sp.; e: Hydrolithon sp. A; f:
Pseudolithophyllum sp.; g: Lithophyllum tesellatum; h: Lithophyllum spp. (branched form); i: Mesophyffum erubescens; j: Lithothamnion funafutiense; k and I: other nonarticulated coralline algal species; m:corals.

Yasufumi Iryu

1172

it from the Pacific region. The use of thinsections for coralline identification renderedit impossible to distinguish some branchedforms of Lithophyiium such as L. kotschyanum and L. pallescens and they are indicated as "Lithophyllum spp. (branchedform)" in the list.
Fossil Assemblages

Figure 9. Sketch of a typical example of
Assemblage B in IE2 (Okierabu-jima). Legend in
Figure 8.

Figure 10.

Porolithon onkodes, Neogoniolithon fosliei,
Spongites sp. A, and Lithothamnion austraie
are chosen as depth-indicative species,
because they occur from the Ryukyu Group
commonly to abundantly and their distribution is very limited in the modern reef environment not only in the Ryukyu Islands but
also in Guam (Gordon et ai., 1976) and
Hawaii (Adey et ai., 1982). Based on thepresence or absence of these species, four
fossil coralline species assemblages aredelineated (Assemblages A, B, C and D) andtheir depth ranges are given as follows.
Assemblage A is characterized by the presence of P. onkodes (Figure 8). This species
is widely distributed in shallow waters of thetropical Pacific Ocean (Adey et ai., 1982;

Sketch of a typical example of Assemblage C in E25 (Okierabu-jima).

Legend in Figure 8.

940.
Table 2.

Fossil nonarticulated coralline algae as depth indicators

Delineation of the nonarticulated coralline
algal species assamblages and their depth
ranges.
Depth Range (m)

0-20

~age
SpeCIes•••••• • •• • • ••• • • ••

PorolitlJoll ullkodes
sp. A

1'.

Lithophyllul1l illsipidumL.
tesrl/atumL

spp. (branched form)
Litlwthal1miolJ australe
flllltlfutiellse
sp. A

L
L

•

RhodolithComparison of depth indicated by the
nonarticulated coralline algal species
assemblages with that by coral communities by N akamori (1986). The upperand lower bars in each column show thedepth ranges determined by the nonarticulated corallines and by the corals,
respectively.

Depth (m)

20

B

A

Algal
Ass.

50

35

C

El
E3

~

E5
ro

.§

~

.a
~

.!!

.:<
0

EG
EIO
E13

~

--

E 17
E20
E 25
K2

-

K3
K4
ro

K5

.§
;0
~

'"

50+

••
•••
••

NeuxulliulitllOll tosliei
N.
(osliei smSIl Matsuda (1989)
Spull.~ites sp. A

Table 3.

Z0-35 35·50+

Ass. A Ass. II As,. C Ass. I)

KG
K7
KB
K9

--

Kl0
Coral
Com.
Depth (m)AIBICh
10 15

D

I
30

E

D

1173

Foslie, 1929; Gordon et al., 1976; Iryu andMatsuda, 1987, 1988; Lee, 1967; Lemoine,
1911; etc.). Most of its occurrence isrestricted to depths shallower than 20 m.
The extent of areal coverage and abundanceof Lithophyllum insipidum are very similar tothat of p. onkodes in the Recent Ryukyu
Islands (Iryu and Matsuda, 1988). Laterobservation reveals, however, that this species
grows rarely at depths from 20 to 30 m in the
Ryukyu Islands. In Hawaii, a few specimensof this species were found from a 15 to 35 m
depth range, although it is principally ashallow-water species (Adey et al., 1982).
Consequently, it seems that L. insipidum is
not a suitable species to use as a depth indicator for the Ryukyu Group. Assemblage A isthought to have been distributed in depths
down to 20 m. The assemblage, which isindicative of the moat environment, wasexpected to be distinguishable from theAssemblage A on the basis of occurrence of
Neogoniolithon frutescens which grows abundantly and whose habitat is restricted within
the moat area of the present-day Ryukyu
Islands. This has not been realized because
an in situ thall us of N. frutescens has notbeen found from the Ryukyu Group.
In Assemblage B, P. onkodes is totallylacking and Neogoniolithon fosliei or Spongites sp. A is found instead (Figure 9). Spongites sp. A is abundant at depths from 0 to 25
m and is rarely observed to a depth of 30 m in
the Recent Ryukyu Islands. This is synonymous with at least a part of N. fosliei sensu
Adey et al. (1982) which is restricted todepths less than 25 m in Hawaiian reefs.
However, this species is not so abundant in
the Pleistocene as in the Recent Ryukyu
Islands. N. fosliei, which occurs abundantlyin the Ryukyu Group, is also selected asa depth indicator. Gordon et al. (1976)
recorded it to depths of 35 m in Guam.
Assemblage B is considered to have existed at
depths from 20 to 35 m.
Assemblage C is composed of species having a wide depth range, such as Lithophyllum

1174

Yasufumi Iryu

tesellatum, Lithothamnion funafutiense andbranched forms of Lithophyllum spp. (Figure10). The absence of P. onkodes, N. fosliei
and Spongites sp. A characterizes Assemblage
C and indicates that this assemblage wasdistributed at depths greater than 35 m.
Rhodoliths are not found from the outcrop
where Assemblage C is observed. In themodern Ryukyu Islands, rhodoliths are foundfrom deep forereef regions exceeding 50 m indepth, where they are distributed sporadically. It is highly probable that this assemblage existed in the depth range from 35 to 50
m or deeper.
Assemblage D is also composed of widedepth-range species and lacks P. onkodes, N.
fosliei, and Spongites sp. A. It is distinguished from Assemblage C in that Lithothamnion australe occurs in association with
Lithothamnion sp. A. In the stratigraphic
section characterized by Assemblage D,
rhodoliths are sporadically scattered in outcrop. Lithothamnion australe is distributedat depths greater than 30 m and occurs veryfrequently at depths greater than 60 m in
Hawaii (Adey et al., 1982). It is thoughtthat Assemblage D existed in the deep forereef environment, exceeding 50 m depth,
where hermatypic corals were highly reduced
in number and abundance was replaced byrhodoliths (Table 2).
Comparison with Coral communities

N akamori ( 1986) recognized five fossil
coral communities (Communities A, B, C, D
and E) in the coral limestone of the Ryukyu
Group based on generic comparison andsedimentological features. Community A
was thought to have been distributed in themoat to the reef crest of the fringing reef or in
the protected shallow water of patch reefs.
Community B was considered to have existed
in the reef edge which stood at almost sea
level. The Communities C, D, and E wereinterpreted as inhabiting water depths from 0
to 15 m, from 10 to 30 m, and from 30 to 100
m on the reef slope, respectively. In order tocompare the bathymetric interpretations der-ived from coralline algae and corals, fossil
coralline algae were collected from nine outcrops on Okierabu-jima and nine on Kikaijima from which Nakamori (1986) examinedfossil corals. The depositional environments
determined by the algae accord well withthose based on corals at 13 localities (Table3), but there are disagreements amongst theremaining five outcrops. This is because thealgal Assemblage C indicates environments
deeper than those suggested by the corals(EIO, K2, K3 and K8). Assemblage C isdiscriminated by negative evidence; namely
three shallow (P. onkodes, Spongites sp. A,
and N. fosliei) and two deep (L. australe andLithothamnion sp. A) water algal species are
not observed. Because the 35 to 50 m depth
range, where Assemblage C is considered tohave been situated, is beyond the safety limitof conventional SCUBA diving, ecologic
information available on living corallines
may not necessarily be sufficient to provide
accurate distributional data. The coralline
bathymeter should be improved in thisrespect. It is concluded that the depositional
environments indicated by algae generally
agree with those based on corals and that thefossil corallines can be as excellent depth
indicators as corals.
Comparison with Foraminiferal assemblages

Noda (1976) discriminated three benthic
foraminiferal assemblages (Assemblages A, B
and C) in the Ryukyu Group on Y oron-jima.
He stated that the Assemblage A characterized an "off-reef floor facies" and the Assemblages Band C a "reef facies". But no quantitative bathymetric data were given for each
assemblage. This makes it difficult to compare quantitatively bathymetric interpretations derived from foraminifera and coralline
algae. However, the fact that their interpretations agree can be verified qualitatively bycomparing the distributional patterns of theflora and fauna. The foraminiferal assemblages are distributed nearly concentrically:
Assemblage C occurs in an area around
Ritcho where the basement rocks are exposed

940.

Fossil nonarticulated coralline algae as depth indicators

at present; areas of Assemblages B and A
surround the Assemblage C area successively.
The distribution of the coralline-algal assemblages is highly concordant with that of foraminifera. In other words, these floral
assemblages are also distributed more or lessconcentrically. Assemblages Band Care
distributed around the area of Assemblage A.
Therefore, paleoenvironments determined by
the nonarticulated coralline algal assemblage
do not contradict those suggested by benthic
foraminifera.

Discussion
Although nonarticulated coralline algae
are distributed from tropical to boreal latitudes and from intertidal to more than 200 m
depths in the modern marine environment,
many geoscientists considered them to betropical shallow-water organisms. Adey and
MacIntyre (1973) pointed out such misunderstandings and gave principles forpaleoecologic interpretation based on thecoralline algae. An increasing number ofstudies since the 1960's on the coralline
population and zonation, coupled withworks on systematics, in northern waters(Adey, 1966; Adey et al., 1976) and in thetropics (Lee, 1967; Littler, 1973a, 1973b;
Littler and Doty, 1975; Gordon et al., 1976;
Adey et aI., 1982; Minnery, 1990) haveshown that the ecologic specificity of many
coralline taxa and morphological groups.
This indicates the great potential of the coralline algae as paleoenvironmental indicators.
In particular, paleontologists have paid attention to ecologic specificity in such things asmorphology of coralline crusts and branches
and generic floral composition.
The coralline growth form, in particular, isthought to be indicative of paleoenvironment,
especially hydraulic energy, based on thefollowing two relationships observed in thepresent-day marine environment:(1) The branching of the thallus increases
with increasing turbulence, namely, densely

1175

branched forms are found in turbulent areas
and open-branched forms in quiet areas. In
such cases, the apices of the branches of dense
forms grow laterally, in response to abrasion,and fuse with adjacent branches to form analgal nodule called a rhodolith (Bosellini and
Ginsburg, 1971; Bosence, 1976, 1983;
1985a).
(2) The high-energy coralline-algal frameworks are constructed from closely superposed thick crusts and mutually fused thickly
branched thalli, whereas those from shelteredenvironments are more delicate and open in
their construction, being composed of thinnerbranches and crusts (Bosence, 1985b). The
subtidal zonation according to coralline
morphologies growing on stable substrata intropical and nontropical regions made by
Steneck (1986) indicates that thick forms
predominate over thin ones at shallower
depths while the reverse relationship isobserved in deeper waters.
These relationships were used to determine
hydraulic conditions of coralline algal bioherms and biostromes by Studencki (1979)
and Bosence and Pedley (1982). However,these observations are not adopted in thisstudy. The relationship (1) is consideredinadequate to adopt because of the following
two reasons. Firstly, this relationship isapplicable to algal-related sediments containing many in-situ thalli of branched species of
nonarticulated coralline algae. Such autochthonous thalli occur less abundantly in the
Ryukyu Group and thus the relationship is oflittle use for this group. Secondly, it is still
uncertain whether the branching species
found from the Ryukyu Group, such as Porolith on sp. A, Lithophyllum spp., and Mesophyllum erubescens, show a similar relationship between branch morphology andhydraulic conditions such as exists in themodern marine environment. My observation of living corallines in the reefs of the
Ryukyu Islands shows that the branch morphology of Porolithon sp. A and Lithophyllum pallescens is highly stable. This means

1176

Yasufumi Iryu

that the relationship (1) does not hold well in
all the branched coralline species. The relationship (2) seems to show a general andrough relationship between the morphology
of corallines forming frameworks and hydraulic conditions or depth and to have many
exceptions. I can give the following example
as disproof. In the reefs of the modern
Ryukyu Islands, it is common that the thickcrustose species, such as Neogoniolithon fosliei
and Spongites sp. A, are closely superposed toform thick robust frameworks at around 15 m
depth on the reef slope, whereas thin andleafy corallines inhabit the basal dead portion of the dendroidal hermatypic corals toform a delicate and open framework on the
more turbulent outer and inner reef flats.
This evidence does conflict with the relationship (2). Consequently, the relationship (2)also can not be used for establishing the kindof paleoenvironmental interpretation attempted in this study.
The floral composition at generic level has
been used for delineating paleobathymetry ofalgal-related deposits (Jones and Hunter,1991). A schematic chart given by Adey
(1979) and Adey et al. (1982) representing
the relative abundance of coralline generawith respect to depth given has been used as aworking standard for paleobathymetry insuch studies. However, Adey (op. cit.) defined neither assemblages nor zones relative to
specific depth ranges. Workers, therefore,
had to interpret the paleobathymetry ofalgal-related deposits, the object of their own
studies, by comparing their floral composition with Adey's scheme. This will possibly
lead the workers to more or less arbitrary
interpretations. Actually, Mankiewicz(1988) pointed out the occurrence of thein-situ branching Mesophyllum as one of theimportant documentation for the determination of water depth at the time of Halimeda
accumulation; she stated that "Adey et al.
(1982) showed that in modern (Atlantic) reef
environments, Mesophyllum typically occurs
in water depths greater than 50 to 60 m."

This figure ignores the fact that the branching
Mesophyllum species, such as M. erubescensand M. canariense, are distributed at shallower depths in the Atlantic and thus seems
to be arbitrary. Therefore, I have presented
a stricter delineation of fossil assemblages andtheir specific depth ranges to avoid suchvagueness.
The coralline bathymeter proposed in thispaper is likely to be applicable to the Pleistocene reef limestones in the broader IndoPacific region, because most of the species
used for the delineation of the assemblages,
such as Porolithon onkodes, Neogoniolithon
fosliei and Lithothamnion australe, have awide geographic distribution in modern
marine environment and are thought to havea similar distribution in Pleistocene time. Insummary, my study indicates that the fossil
coralline-algal assemblages provide a reasonable paleobathymetric information on thedepths of deposition of the Pleistocene reeflimestone complex.
Conclusions
Four fossil nonarticulated coralline algal
species assemblages were discriminated fromthe coral limestone sequence of the Pleistocene Ryukyu Group. Each assemblage
indicates a specific depth range.
Paleoenvironments inferred from thesealgal assemblages accord well with thosederived from coral communities and benthic
foraminifera. It is considered that the nonarticulated coralline algae are excellent depth
indicators, and we can reconstruct detailed
paleoenvironments by applying the coralline
bathymeter.
Acknowledgment
I am most grateful to Professor Kei Mori of
the Institute of Geology and Paleontology,
Tohoku University, for his valuable suggestions and critical reading of the manuscript.
I am much indebted to Professor Paul Cop-

940.

Fossil nonarticulated coralline algae as depth indicators

per, Department of Geology, Laurentian
University, Canada and Professor Tsunemasa
Saito of the Institute of Geology andPaleontology, Tohoku University, for correcting the English text. Thanks are also expressed to Dr. Toru Nakamori of the same Institute and Mr. Shinya Matsuda of College of
Education, University of the Ryukyus, fortheir useful advice. Deep appreciation isexpressed to Mr. Masaaki Shishido of theInstitute of Geology and Paleontology, Tohoku University for making thin sections.

References
Adey, W.H., 1966: Distribution of saxicolous crustose corallines in the northwestern North Atlantic. Jour. Phycol., vol. 2, p. 49-54.
- - , 1970: A revision of the Foslie crustose coralline herbarium. Det Kong. Vidensk. Selsk.,
Skrif., no. I (annual volume in 1970), p. 1-46.
- - , 1979: Crustose coralline algae as microenvironmental indicators for the Tertiary. In, Gray, J.
and Boucot, A.J., eds., Historical biogeography,
plate tectonics and the changing environment, p.
459-464. Oregon State Univ. Press, Corvallis.
- - , and MacIntyre, I.G., 1973: Crustose coralline
algae: a re-evaluation in the geological sciences.
Geol. Soc. A mer., Bull., vol. 84, p. 883-904.
- - , Masaki, T. and Akioka, H., 1976: The distribution of crustose corallines in eastern Hokkaido
and the biogeographic relationships of the flora.
Bull. Fac. Fish. Hokkaido Univ., vol. 26, p. 303313.
- - , Townsend, R.A. and Boykins, W.T., 1982: The
crustose coralline algae (Rhodophyta: Corallinaceae) of the Hawaiian Islands. Smithsonian
Contr. Mar. Sci., no. 15, p. 1-74.
Bosellini, A. and Ginsburg., R.N., 1971: Form andinternal structure of Recent algal nodules(rhodolites) from Bermuda. Jour. Geol., vol. 79,
p.669-682.
Bosence, D.W.J., 1976: Ecological studies on two
unattached coralline algae from western Ireland.
Palaeontology, vol. 19, p.365-395.
- - , 1983: Coralline algal frameworks. Jour.
Geol. Soc. London, vol. 140, p.365-376.
- - , 1985a: The morphology and ecology of amound-building coralline alga (Neogoniolithon
strictum) from the Florida Keys. Palaeontology, vol. 28, p. 189-206.
- - , 1985b: Preservation of coralline-algal frameworks. Proc. 5 th Int. Coral Reef Congr.,

1177

Tahiti, vol. 6, p.623-628.
- - and Pedley, H.M., 1982: Sedimentology andpaleoecology of it Miocene coralline algal biostrome from the Maltese Island. Palaeogeogr.,
Palaeoclimatol., Palaeoecol., vol. 38, p. 9-43.
Campbell, S.J. and Woelkerling, Wm. J., 1990: Are
Titanoderma and Lithophyllum (Corallinaceae,
Rhodophyta) distinct genera? Phycologia, vol.
29, p. 114-125.
FosIie, M.H., 1929: Contribution to a monograph of
the Lithothamnia. 60p. Det Kong. Selsk.
Vidensk. Mus., Trondheim (after the author's
death, collected and edited by Printz, H.).
Gordon, G.D., Masaki, T. and Akioka, H., 1976:
Floristic and distributional account of the common crustose coralline algae on Guam. Micronesica, vol. 12, p.247-277.
Heydrich, F., 1900: Eine neue fossile Algae aus
Riukiu, L. nahaense sp. nov. Jour. Geol. Soc.
Japan., vol. 7, unpaged.
Iryu, Y., 1984: Discovery of Recent deep waterrhodoliths from the Ryukyu Islands, southwestern Japan, and its significance. Prompt. Rep.
Compreh. Sci. Surv. Ryukyu Archipelago, no. I,
p.47-55. (in Japanese with English abstract)- - , 1985: Study on the Recent rhodoliths aroundthe Ryukyu Islands. Ibid., no. 2, p. 123-133.
(in Japanese with English abstract)- - , 1986: Litho- and chronostratigraphy of the
Ryukyu Group on Y oron-jima. Geol. Soc.
Japan, Abstracts with Programs, 93rd Ann.
Meet., Yamagata, p. 131. (in Japanese)- - , 1991a: Algae and sea grasses of coral reefs
around Ishigaki Island and its adjacent area.
In, Mezaki, S., ed., The coral reefs of Ishigaki
Island, p. 73-86. WWF Japan, Tokyo. (inJapanese with English abstract)- - , 1991 b: Algae and sea grasses of the coral reefs
on the east of Kara-dake, Ishigaki Island, Ryukyu Islands. Ibid., p. 159-171. (in Japanese withEnglish abstract)- - and Hayasaka, S, 1985: Topography andmarine sediments in a range of rhodoliths.
Prompt Rep. Compreh. Sci. Surv. Ryukyu Archipelago, no. 2, p.117-121. (in Japanese withEnglish abstract)- - and Matsuda, S., 1987: Distribution of nonarticulated coralline algae in the reef environmentof the Ryukyu Islands. Kaiyo-kagaku, vol. 19,
p. 524- 529. (in Japanese)- - and - - , 1988: Depth distribution, abundanceand species assemblages of nonarticulated coralline algae in the Ryukyu Islands, southwesternJapan. Proc. 6th Int. Coral Reef Symp., Townsville, vol. 3, p. 101-106.
- - , Nakamori, T. and Yamada, T., 1992: A unit oflithostratigraphic classification of the Ryukyu

1178

Yasufumi Iryu

Group, Pleistocene reef complex deposits. Jour.
Sedimentol. Soc. Japan, no. 36, p.57-66. (inJapanese with English abstract)- - , and Yamada, T., 1991: A preliminary reporton Pleistocene sea level changes recorded in the
Ryukyu Group on Toku-no-shima andOkierabu-jima, Ryukyu Islands. In, Professor
Hisao Nakagawa Taikan Kinenjigyo-kai, ed..
Essays in Ceology (Professor Hisao Nakagawa
Commemorative Volume), p. 73-83. Toko
Printing Co. Ltd., Sendai. (in Japanese withEnglish abstract)
Ishijima, W., 1938: New species of calcareous algae
from several Tertiary and later limestone of the
Ryukyu Islands. Japan. Jour. Ceol. Ceogr., vol.
15, p. 13-16.
- - , 1942a: On the coralline algae from the Ryukyu
Limestone of Kotosho (Botel Tobago Island).
Taiwan Chigaku-kiji, vol. 13, nos. 2-3, p. 78-84.
(in Japanese)- - , 1942b: Fossil Lithoporella and its classification. Ibid., vol. 13, no. 4, p. 2-12. (inJapanese with English systematic description)- - , 1944: On some fossil coralline algae from the
Ryukyu Limestone of the Ryukyu Islands andFormosa (Taiwan). Mem. Fac. Sci. Taihoku
Univ., Ser. III, vol. I, p.49-76.
- - , 1954: Cenozoic coralline algae from the Western Pacific. 87 p. Yuho-do, Tokyo.
Jones, B. and Hunter, I.G., 1991 : Corals to rhodolites
to microbialites-a community replacement
sequence indicative of regressive conditions.
Palaios, vol. 6., p.54-66.
Lee, R.S.K., 1967: Taxonomy and distribution of the
melobesioid algae on Rongelap Atoll, MarshallIslands. Canad. Jour. Bot., vol. 45, p.9851001.
Lemoine, P., 1911: Structure anatomique desMelobesiees. Application 1i la classification.
Ann. l'Inst. Oceanogr., tome 2, p. 1-213.
Littler, M.M., 1973a: The distribution, abundanceand communities of deep water Hawaiian crustose Corallinaceae (Rhodophyta, Cryptonemiales). Pac. Sci., vol. 27, p. 281-289.
- - , 1973b: The distribution and community structure of Hawaiian fringing reef crustose Corallinaceae. Jour. Exp. Mar. Bioi. Ecol., vol. II,
p. 103-120.
- - and Doty, M.S., 1975: Ecological components
structuring the seaward edges of tropical Pacificreefs: the distribution, communities and productivity of Porolithon. Jour. Ecol., vol. 63, p.
117-129.
Mankiewicz, c., 1988: Occurrence and paleoecologic
significance of Halimeda in late Miocene reefs,
southern Spain. Coral Reefs, vol. 6, p. 271-79.
Matsuda, S., 1987: Nonarticulated coralline algae in

the Ryukyu Islands. Kaiyo-Kagaku, vol. 9, p.
162-167. (in Japanese)- - , 1989: Succession and growth rates of encrusting crustose coralline algae (Rhodophyta,
Cryptonemiales) in upper fore-reef environment
off Ishigaki Island, Ryukyu Islands. Coral
Reefs, vol. 7, p. 185-195.
- - and Tomiyama, T., 1988: An investigation of
Recent deepwater rhodoliths from the Ryukyu
Islands. Bull. Coll. Educ. Univ. Ryukyus, no.
33, p. 343-354. (in Japanese with English
abstract)- - , Iryu, Y. and Nohara, M., 1992 (in press):
Rhodoliths on the deep forereef of Okinawajima, Ryukyu Islands. Jour. Sedimentol. Soc.
Japan, no. 37. (in Japanese)
Minnery, G.A., 1990: Crustose coralline algae fromthe Flower Garden Banks, northwestern Gulf of
Mexico: controls on distribution and growthmorphology. Jour. Sed. Petrol., vol. 60, p.9921007.
Minoura, K., 1979a: Sedimentological study of Ryukyu Group. Sci. Rep., Tohoku Univ., 2nd Ser.
(Ceol.), vol. 49, p. 1-70.
- - , 1979b: Depositional environment of algalballs of the Ryukyu Group. Ceol. Stud. Ryukyu Islands, vol. 4, p.55-62. (in Japanese withEnglish abstract)- - and N akamori, T., 1982: Depositional environment of algal balls in the Ryukyu Group, Ryukyu Islands, southwestern Japan. Jour. Ceol.,
vol. 90, p. 602-609.
Nakamori, T., 1986: Community structure of Recent
and Pleistocene Hermatypic corals in the Ryukyu
Islands, Japan. Sci. Rep., Tohoku Univ., 2ndSer. (Ceol.), vol. 56, p. 71-133.
Noda, M., 1976: Ryukyu Limestone of Yoron-to(Yoron Island). Jour. Ceol. Soc. Japan, vol. 82,
p. 367-381. (in Japanese with English abstract)
Nohara, M., Ohshima, K., Yokota, S., Murakami, F.,
Iuchi, Y. and Ikeda, K., 1979: Marine sedimentsfrom the adjacent sea around the Okinawa
Islands. Environmental Research in Japan, vol.
2 (annual volume in 1979), p. 3-28. (in Japanesewith English abstract)
Penrose, D. and Woelkerling, Wm. J., 1988: A taxonomic reassessment of Hydrolithon Foslie, Porolith on Foslie, and Pseudolithophyllum Lemoine
emend. Adey (Corallinaceae, Rhodophyta) andtheir relationships to Spongi/es Kiitzing.
Phycologia, vol. 27, p. 159-176.
Studencki, W., 1979: Sedimentation of algal limestones from Busko-Spa environs (Middle
Miocene, Central Poland). Palaeogeogr.,
Palaeoclimatol., Palaeoecol. , vol. 27, p. 155-165.
Tsuji, Y., Sunouchi, H., Yamamura, T., Kodato, T.,
Yuki, T. and Iwamoto, H., 1989: Recent marine

940.

Fossil nonarticulated coralline algae as depth indicators

sediments and their depositional environments,
to the west of Miyako-jima, Ryukyu Islands.
Chikyu, vol. II, p. 612-617. (in Japanese)

1179

Woelkerling, Wm. 1., 1988: The coralline red algae.
268 p. Oxford Univ. Press, London.

Akazaki ~w,rr, Araki hLt:, Asado ijiJlp, Chabana *1t, China 9;015, Furusato tI!It, Goran
1&00, Gusuku:!$;, Higashi-ku *iK, Hyakunodai BZ il, Inutabu :;i\:EEl;fp, Itokina **15,

Kikai-jima ~3'F-!1i;, Nagamine 7k~, Nama mrs', Nishi t;t, Okidomari ¥tprEl, Okierabu-jima¥tp7k&li1l!1i;, O-yama :;kill, Ritcho 11:*, Sakibaru w,rr)JJl:, Serikaku iWJiflJjt, Shimohirakawa
T:if }If, Shimoshiro T:!$;, Shinjo *'T:!$;, Somachi.!f! 1IlJ, Sumiyoshi {± E, Tamina EEl .gr,
Takigawa it}lf, Toku-no-shima :iI!f-z!1i;, Tomori 1Af lJ, Wan f,%, Yaja ~~, Yakomo ~T-/B:, Yoron-jima ~§tfij!1i; .

• ¥~~~tI*~m.~L~~.®~~~~:.¥~!1i;~~.!1i;,#7k&li1l!1i;,~z!1i;,~3'F-!1i;F:::.5t;fpi" 0~fJ.9* • .f:j(~~,*,~.®~ ~::l ~1~E~~~ L tc. o m::tE~ • .f:j(71J!1i;)i!ijill
i'Ia~V.:.:tovt0.®~ ~::{ ~ ~ ~Jtt'i:iJ'G, FiiJ~~,*,v.:. 4 ":)~1~E.®~ ~::{ ~~1iHliU]1j
L, :t;h.::c;h~1~E~1i~5t;fp~~~:lt5E L tc. o 1~E.®~ ~::t ~lJ:f1i~~i"tl7j(~ft, 1~
E~ ~ ,"'lJ:f~v':' J: 0 :lt5Etl7j(~ UH:fW5JflJl¥rC';5 i), 1~E.®~ ~ ~ ~ iJ;tI~~, !f#v.:. tI
7j(~~tl'i.~ L~~ffl-c';50 C b'J;'F1j1jJj Ltc. o#~Hft)(

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 167, pp. 1180-1223, 18 Figs., September 30, 1992

941. LOWER AND MIDDLE TRIASSIC RADIOLARIANS FROM
MT. KINKAZAN, GIFU PREFECTURE, CENTRAL JAPAN*
KAZUHIRO SUGIYAMA
Department of Earth and Planetary Sciences, School of Science,
Nagoya University, Nagoya 464-01

Abstract. Well-preserved radiolarians have been obtained from the Lower and Middle
Triassic in Mt. Kinkazan, Gifu City, Gifu Prefecture, central Japan. They are represented
by three assemblages, namely the Parentactinia nakatsugawaensis assemblage (Spathian orolder), Hazmadia gifuensis sp. nov. assemblage (early Anisian) and Triassacampe caranata
assemblage (middle Anisian). On the basis of field observations, radiolarian dating andsome sedimentological examinations, the general stratigraphy in the studied area is tentatively reconstructed as a sequence of Lower Triassic black shale, siliceous shale to chert, andMiddle Triassic bedded chert in ascending order. The occurrence of Permian radiolariansin the studied area is also discussed. Twenty-six species are newly described and four new
genera are also proposed herein.
Key words.
central Japan

Radiolaria, Lower to Middle Triassic, Mt. Kinkazan, Gifu Prefecture,components of Permian radiolarian faunas(e.g. Ishiga et at. 1982a, 1982b; Kozur andMostler, 1989; Nazarov and Ormiston, 1985).
Complete lack of the information of radiolarian fossils near the Permo-Triassic boundary,however, prevents our precise tracing of theevolutionallineages across the P-T boundary.
Therefore, what effect the most severe mass
extinction during the Phanerozoic time hadon radiolarian phylogeny remains an unsolved problem.
The P-T boundary is also very interestinggeologically because many paleoenvironmental problems at that time remain unsolved. This situation is applicable to the
Paleozoic-Mesozoic sedimentary complex in
Japan, such as the Mino and Chichibu Terranes, and it seems mainly due to ourinsufficient knowledge about the Lower Trias-

Introduction
A large amount of knowledge concerning
late Anisian to Rhaetian radiolarians has
been accumulated chiefly in European Tethyan region (e.g. De Wever et at., 1979;
Dumitrica, 1978a, 1978b, 1982a, 1982b 1982c;
Dumitrica et at., 1980; Kozur and Mostler,
1972, 1978, 1979, 1981, Lahm, 1984), western
North American region (e.g. Pessagno andBlome 1980; Pessagno et at., 1979; Blome,
1983, 1984; Yeh, 1989) and western Pacificregion (e.g. Nakaseko and Nishimura, 1979;
Yao, 1982; Yao et at., 1980; Cheng, 1989;
Blome et at., 1987, Yeh, 1990). Thus, itappears that now we have enough faunal
information to reconstruct the phylogenetic
relationship between the Triassic and Jurassic
radiolarians.
On the other side, recent progress of
research on radiolarians has revealed rich

SIC.

In order to clarify the above-mentioned
taxonomic and geologic problems, I have
performed detailed field investigation in Mt.

'Received February 22, 1992; revised manuscript
accepted July 10, 1992
1180

941.

Lower and Middle Triassic radiolarians from central Japan

Kinkazan, Gifu Prefecture, central Japan,
from which Ando (1987) reported the occurrence of Middle Triassic to Early Jurassic
radiolarians in chert beds and Middle to Late
Permian radiolarians in siliceous shale beds.
He also reported the occurrence of siliceous
rocks which yield Early Triassic spicularradiolarians described by Sash ida (1983). I
have reexamined this area and collected morethan 1,000 rock samples of black shale,siliceous shale and chert beds abundantly
bearing Permian and Early to Middle Triassic
radiolarians. Consequently, many new facts
have been revealed on the geology of theLower to Middle Triassic in this area, especially mode of occurrence of Permian
radiolarians, and the obtained radiolarians
also permit me to develop some new ideas onradiolarian phylogeny, particularly on thephylogenetic relationship between the orders
Entactinaria and Nassellaria, which
Sugiyama (1990, 1991 a, 1991 b) has alreadytreated preliminarily.
The present study, as the first of a series,
focuses on describing three Early to Middle
Triassic radiolarian assemblages recognizedso far and the characteristic component
species of each assemblage, after a brief
mention of the geologic setting.
Geologic setting

Mt. Kinkazan, located approximately at
the center of Gifu City, consists of dominantchert beds with subordinate amount of blackshale, siliceous shale and sandstone beds. It
lies on the southern margin of the Mino
Terrane which is composed of the PaleozoicMesozoic sedimentary complexes of sandstone, shale, chert, limestone and greenstone(Mizutani, 1990), and belongs to the Complex
3 of Otsuka (1988) and Kamiaso Unit of
Wakita (1988). I have made a detailed field
investigation and sampling along routes A, B<> Nagara River

GI1u Castle

Mt. Kinkazan

LEGEND

Dauaternary
Iwato
Park

~ Paleozoic - Mesozoic~ sedimentary complex(mainly chert)
Drive Way

Figure 1.

1181

Index map showing the localities of three routes A, Band C.

Kazuhiro Sugiyama

1182

KIN 73I

grayish togreenishbedded chert
KIN 74,75

blackish to grayish
bed d e d c her t ----]"'i>J!Ui'~~~w::::::::KIN 60,61-65,~

.-:

-.)"

'~:

-'.'

Jurassic
chert

-I-

501

KIN 540-black muddy
chert

Fig. 3~N 050m'=====~

Figure 2. Route map of the route A, also showing the sampling locations (KIN),
mean that they were obtained from a continuous sections,and C (Figs. 1-3). Route A includes, Localities 2 and 3 of Ando et al. (1991), whereas
routes Band C contain their Localities I and4, respectively. I can unfortunatelly deal
only with route A in this study as a detailed
discussion is beyond the scope of this paper.
The results regarding the other two routes anda total discussion are hoped to be publishedin the near future.
In route A, bedded chert with a small
amount of black shale and siliceous shale
beds are well exposed along the roadcuts.
They are complicatedly folded and have someminor faults. Chert beds have considerable
variation in color, from black, gray, andgreen to red. Reddish chert is restricted in
the distribution to the northern-northeasternpart of this route; in contrast, grayish to
blackish chert predominates in the southernpart of the route. Blackish chert is rather
muddy and usually grades into black to
blackish gray, bedded siliceous shale. This
type of bedded chert is termed black muddy
chert in this study. The central part of theroute is almost entirely occupied by greenish
to grayish chert. Moreover, black shale andrelatively massive siliceous shale to chert
outcrop in some places.
Well-preserved late Middle to early Late
Permian and Early to Middle Triassic

Hyphenated numbers

radiolarians have been obtained from thisroute. As a result of the examination ofprincipal species composition, four radiolarian assemblages, one Permian and the others
Triassic, have been recognized. The Permian radiolarian assemblage is characterized
by abundant occurrence of Follicucullus
scholasticus Ormiston and Babcock. F.
monacanthus Ishiga and Imoto was also
obtained from the sample KIN 28. The age
is thus late Middle to early Late Permian,according to Ishiga (1986). Triassic
radiolarian assemblages are newly discriminated in this study, and named Parentactinia nakatsugawaensis (Pn) assemblage(Spathian or older), Hozmadia gifuensis sp.
nov. (Hg) assemblage (early Anisian) andTriassocampe coronata (Tc) assemblage(middle Anisian) in chronologic order. The
detailed definitions and characteristic speciesof each assemblage are fully discussed in thenext chapter.
Then one can easily recognize that there isa close relationship between lithofacies andradiolarian assemblages. For example,
black muddy chert yields representative
species of the Pn assemblage and so on. It isconsequently suggested that differences oflithofacies reflect differences of age, and thegeneral stratigraphy of route A is roughly

941.

Lower and Middle Triassic radiolarians from central Japan~.+---KIN

1183

56,57

f'-::;:<--black muddy chert

greenish to reddish
bedded chert
KIN 41,42,43,44,45

29,30,31,32,33,34,
35,36,37,38,39,40,
KIN 22,23,24,
25,26,27,28

black

to chert

KIN

N===::::I~Om ~0,=,

Figure 3.

Enlargement of the western part of the route A.

reconstructed as a sequence of black muddy
chert, grayish to greenish bedded chert andgreenish to reddish bedded chert in ascendingorder from Spathian to middle Anisian interval.
The development of other lithofacies andtheir relationship to the occurrence of Permian radiolarians remains uncertain. It isnoteworthy that Permian radiolarians from
Mt. Kinkazan area sometimes exhibit peculiar
overlaps which strongly conflict with theirpreviously known chronologie ranges, asmentioned by Ando et al. (1991). Besides
such a fact, personal investigations have
proved that they can co-occur even with
Triassic radiolarians in a single sample. In
order to clarify the problem, I describe in thefollowing lines the detailed litho- and biostratigraphy in the part of route A shown in
Figure 3, which corresponds to Loc. 2 ofAndo et al. (1991).
In Figure 3, five units are recognized basedon lithology and contained fossils, and they

are conveniently called units A to E. The
unit A is composed of black shale and sometimes yields poorly preserved, spherical
radiolarians. This unit rarely yields molded
Follicucullus scholasticus (KIN I). Similar
black shale beds corresponding to the Loc. 3
of Ando et al. (1991), exposed in the easternpart of route A in fault contact with theJurassic chert beds, also yield some Permian
radiolarians such as F. scholasticus, Pseudotormentus kamigoriensis De Wever and Caridroit (KIN 74 and 75). Ando et al. (1991)
mentioned that the unit A occurs in fault
contact with unit B, but the fault seems to bea negligibly small slip along the bedding
plane.
The unit B is composed of blackish tograyish, sometimes greenish gray, wellstratified siliceous shale to chert. It apparently resembles "Toishi-type" shale definedby Imoto (1984) but exactly differs in its
uniform content of organic remains. All thebeds dip nearly 90° and no intraformational

1184

Kazuhiro Sugiy ama

Figure 4. 1: Follicucullus scholasticus Ormiston and Babcock, ESN 14628 1, KIN 32. 2: Follicucullus
biparlilus Caridroit and De Wever, ESN 146238, KIN 18. 3·: Follicucullus monacanlhus Ishiga and Imoto,
ESN 146237, KIN 28. 4: Pseudoalbaillella globosa Ishiga and Imoto, ESN 146282, KIN II . 5 : Albaillella
Iriangularis lshiga, Kito and lmolO, ESN 14628 3, KIN 13. 6: Enlaclinia sp., ESN 146284, KIN 34. 7:
Ormistonella robusta De Wever a nd Caridroit, ESN 146245, KIN 32. 8: Ishigaum sp. , ESN 146285, KIN 22.
9 : Lalenlijislula (?) sp., ESN 146286, KIN 34. All scale bar = 50 ,urn.

folding is observable although some minor
faults exist. Ando et al . (1991) reported theoccurrence of only Permian radiolarians inthis unit (corresponding to their Locality
JMP 1334). However, I have revealed thatthey are commonly accompanied by thecomponent species of the Pn assemblages andeven Triassic-type conodonts. Moreover, thechronologic ranges of P. globosa Ishiga andImoto and Albaillella triangularis Ishiga, Kito
and Imoto , obtained from samples KIN 4 and
13 respectively, are restricted to the Middle
Permian and Late Permian, respectively(Ishiga, \986) .
The stratigraphic relationship between theunits B, C and 0 is not supported by the fossil
contents. The unit C is apparently massive
siliceous shale to chert, and exposed, with an
obscure boundary, between units Band 0 ona small scale. This unit contains only Permian radiolarians and correlates with the F.
monacanthus Range-zone to F. scholasticus
Assemblage-zone of Ishiga (1986).
Unit 0 is composed of black muddy chert,
and yields especially well-preserved radiolarians which are representatives of the Pn941.

Lower and Middle Triassic radiolarians from central Japan

11 85

Figure 5. (a): Polished surface of the sample KIN 32. Scale bar = I cm. (b): Etched surface of thesame sample. P=Permian exotic block. T = Triassic matrix. Scale bar = I cm. (c) and (d): Enlargementsof the parts shown in (b) . Scale bars = 200 ,urn. Arrows point Fo/licliclIlllls scholasliclis.

assemblage sometimes accompanied by some
Permian radiolarians which occur in the unit
B. Of special interest is that some beds ofthis unit include a large amount of cherty
exotic rocks which are commonly granule topebble, sometimes boulder in size and visible
to the naked eye (Figure 5) . Observation of
the etched surfaces on such peculiar beds hasrevealed that the component species of the Pn
assemblage occur only in the matrix , whereas
contained granules to pebbles yield only
Permian radiolarians. The beds naturally
contain much smaller, cherty clastic grains
which are quite easy to observe under the
microscope because they are much moresiliceous than the matrix (Figure 6) .
There are several meters of barren rock
between the units 0 and E. The latter unit iscomposed of greenish to reddish bedded chertand characterized by the occurrence of themembers of the Tc assemblage. A fault may
exist between both units because of the lackof the Hg assemblage. It is interesting thatthe sample KIN 44 of this unit also yields
Permian radiolarians.
Except for units A and C, it is apparent
from the above descriptions and Table I that
Permian radiolarian-bearing beds can beclassified into two types ; (1) the beds simultaneously yielding Triassic radiolarians and(2) the beds conformably over- and underlain
by Triassic radiolarian-bearing beds. The
latter obviously indicates an abnormal modeof occurrence of Permian radiolarians in the
Triassic beds. Concerning the former type, [must conclude that all the Permian radiolarians are either reworked fossils or from thePermian exotic rocks and clastic grains, basedon the facts confirmed in the units Band D .
This is the best explanation for the peculiar

11 86

Kazuhiro Sugiyama

Figure 6. Photomicrographs of cherty clastic grain in the sample KIN 32. l a and 2a; open ni co l, lb a nd
2b ; closed nicols, X 62.

co-occurrence of Permian radioralian s reported by Ando et al . (1991) . The preci se stratigraphic position of black shale represented byunit A is at the present time not well understood , but judging from field observation s
and the fo ssi ls it contains, it seems certainthat its position is the lowest of all the lithofacies. Consequently, the general stratigraphy of route A is reconstructed as follows inascending order: (I) bl ac k shale , (2)siliceous shale to black muddy chert rich in

Permi an reworked fo ss ils, with o r without
conspicuous exotic blocks, (3) gray togreenish-gray bedded chert and (4) greenish
to reddi sh bedded chert (Figure 7) . In thi s
study I provisionally consider th at (I) is
stratigraph ica lly just beneath (2). Unit C isregarded as an allochthonous block o r bl ocks
in the Lower Tri assic.

941.

Lower and Middle Triassic radiolarians from central Japan

Early to Middle Triassic radiolarianassemblages
As mentioned in the preceding chapter,
three Triassic radiolarian assemblages arerecognized in route A on the basis of principal species composition. They are chronologically as follows; (1) Parentactinia nakatsugawaensis assemblage, (2) Hozmadia
gifuensis assemblage and (3) Triassocampecoronata assemblage. In the following, diagnostic species are given and the age of each
assemblage is discussed.
Parentactinia nakatsugawaensis (Po) assemblage

This assemblage is well represented by theradiolarian microfauna obtained from black
muddy chert, and characterized by abundantoccurrence of Parentactinia nakatsugawaensis Sash ida. Other diagnostic species are
Hozmadia ozawai sp. nov., Tripedocorbis sp.
A, Zevius yaoi sp. nov., Tetrarchiplagia simplex sp. nov., Cryptostephanidium longispinosum (Sashida), Pseudostylosphaera
kozuri sp. nov., Archaeosemantis cristianensis
Dumitrica, Parentactinia okuchichibuensis(Sashida), Cenosphaera andoi sp. nov.,
Pegoxystris mizutanii sp. nov. and PantanelHum (?) virgeum Sashida. The occurrence ofZamolxis dumitricai sp. nov., Tetrarhopalus
itoigawai sp. nov., Triassobipedis (?) aetoides
sp. nov. and Polyentactinia (?) biacus sp. nov.
are common in some samples but usually rare.
The occurrence of following species is rare;
Poulpus nishimurae sp. nov., Zevius perarmatus sp. nov., Hinedorcus holdsworthi sp.
nov., Entactinia morii sp. nov., Parasensagon
leptaleus sp. nov., Parentactinia ramosus (Sashida), Polyentactinia (?) crux sp. nov.,
Pentabelus furutanii sp. nov., Pegoxystris sp.
A, Tiborella agria sp. nov. and Plajkerium (?)
antiquum sp. nov. Many other indeterminable entactinarian and spumellarian species
are present in this assemblage. Abundanceof entactinarian species marks this assemblage, whereas nassellarian and spumellarianspecies are relatively rare. This assemblage1187

is easily distinguished from the Hozmadia
gifuensis assemblage by lacking H. gifuensis
sp. nov.
This assemblage contains most of the Early
Triassic radiolarians described by Sashida(1983, 1991). Co-occurring conodonts fromsome samples represent the Neosnathodus
homeri assemblage of Koike (1981).
Accordingly the age of this assemblage isconsidered to be Spathian, but the lower limit
is still uncertain.
Hozmadia gifuensis (Hg) assemblage

This assemblage is defined by the predominant occurrence of Hozmadia gifuensis sp.
nov. Other characteristic species are Nofrema (?) gigantoceras sp. nov., Triassocampe (?) sp. A, Zevius spp. including
undescribed forms, Cryptostephanidium longispinosum (Sashida), Cryptostephanidium
sp. cf. C. verrucosum Dumitrica, Archaeosemantis cristianensis Dumitrica, Parentactinia nakatsugawaensis Sashida, Katorella
bifurcata Kozur and Mostler and Plajkerium(?) antiquum. Of these C. longispinosum, A.
cristianensis, P. nakatsugawaensis and Pia/kerium (?) antiquum are common to the Pn
assemblage. The occurrence of the first three
species in the Hg assemblage is, however, farless frequent than in the Pn assemblage, while
the last species is much more frequent in thisassemblage. The occurrence of Poulpus nakasekoi sp. nov. and spicular radiolarians
such as Tetrarchiplagia spp. is common to
rare. Moreover, many undescribed
polyentactiniids (?) and oertlispongids cooccur with above mentioned species. This
assemblage is distinguished from the Triassocampe coronata assemblage by lacking typical species of Triassocampe.
Although the age of this assemblage is notdirectly known, it is presumed to be early
Anisian because of the following two reasons: (1) The specific composition indicatesthat the Hg assemblage is undoubtedly
younger than the Pn assemblage and older
than the following Tc assemblage. (2) Mat-

Kazuhiro Sugiyama

1188

Table 1.

~

List of radiolarians from the route A. Abbreviations: b.-black shale; b.m.c.-black
muddy chert; Hg-Hozmadia gifuensis assemblage; Pn-Parentactinia nakatsugawaensis assemblage; Tc- Triassocampe coronata assemblage.

~
Species(!l-I

siliceous shale. chert (8)Uthofacles (Unit)b.

Rad. assemblagePn
Pn Pn Pn
Pn
Pn
Pn
P PnPn +P Pn PnPn +P P +P +P P +pPn Pn +P P P+pPnPnPPP P P P P~mple(KIN)

Tetrarr:hlplsg/a .'mp/ex "p. nov.
T.
"pCp).
Zamobtls dumlrrlcaJ "p. nov.
Hozmadfa ozawal sp. nov.
glfUansls "p. nov.
H.
Il'OulpuS n_ .../COI "p. nov.
P.
nlshlmume "p. nov.
Trlassocampe mytBmcoryo .p. nov.
comnata BraglnT.
"p. an. T. dlonllnl. Bragln
T.
.Cr)
"p.
A
Spongosll/carmlger _ell sp. nov.
scabllUrrflus sp. nov.
S.
Trt>edoco"'Is "p. A
Hlnedorcus holdswonhl "p. nov.
Nofrema (1) glg_mo "p. nov.
Trlassoblpedls (1) a9loldes sp. nov.
ZevbJs perarmatus "p. nov.
yaol .p. nov.
Z.
Entac"n/a molll .p. nov.
CryplOSlep/lanldlum /onglsplnosum (SBshlda).p. cr. C. venucosum Dumnrlca
C.
EpllnglUm manfredl Dumnrlca
T8I18JtropaiJs lIo/gawai sp. nov.
Pam_on I~eus sp. nov.
vat1ab111s (Nakaseko and Nishimura)P.
Pseudoaty/osphaem compacta (Nakaseko and Nishimura)P.
/tDzurt sp. noY.
P.
"p.A
sp(p).
P.
Archaeosem~s cr/srtanansls Dumllrlca
Palllntaclln/a nalallsugawaansls Sashlda
olaJChlchlbUensis (SBshlda)
P.
P.
ram.,... (Sash Ida)
Po/yentac"nfa (?) blaws .p. nov.
P. (1)CfUX sp. nov.
P. (1)&PIP)·
Pentabelus IUrutanU sp. nov.
ASITOCantnJS pulcher Kozur and Mostl.r
Canosp/laem andol sp. nov.
C.
c/athmra Parana
KalDtBHa bllUrcara Kozur and Mostler
OenJIspongus dlacan/hus sp. nov.
PegoxysD1s m/zutanH "p. nov.
P.
&p.A
OertUspongldae gan(n). et .p(p). Indet.
PenraneOiJm (1) vllf18Um Sashlda
PlaII<et1um (1) ant/quum 'p. nov.
P.(1)
"p.
TIboIllUa ""ria "D. nov.
Entactlnla sp(p).
Heg/er/a (1) &p.
CopIcyrma "p.
ISh/gaum sp.
LalanIJIIstufa (1) &pIp).
"NBZ8IDV8//8' sp.
Onnls_fa robUsra De Wever and Garldron
Poeudotormantus laIm/gollansis De Wever and Garldron
TtP/anospongus sp.
AlbalU8Ua D1snau/arls Ishlga. Kno and Imoto
FoBlcuculluss blpalfltuo Garldroft and De WeverF.
monacanthus Ishlga and ImotoF.
scholastlcus Ormiston and Babcock
F. .p. cr. F. V8IIIrlcosus Ormiston and BabcockF.
sp(P).
Poeudoall>lllll8Ha globosa Ishlga and ImotoP.
&pep).

...

1 2 3 4 5

Isiliceous sh .• ch. (C)..

6 7 8 9 10 1112131415 1617181920 2122232425 262728

.., ·
·
·
·
·
·
·
·
·
,
···· ···· ···· ··· .'· ···· ··· ·· ··· · ···· ·· ·· ..·:
··
··
···
I,
·
·
,
·
·
··
··, ,,···· ·····:e'· ••··· ····· .' · .'
···
····,
···
·
,, ,, ,,I

, ,, ,,
, ,,
,
, ,

, ,
, , ,
I

I

I

I

I

I

'

I

I
I

samples from acontinuous section

~

'.

··
··,
··,
····

· ..
·
.....• ........ •••••..
.
••••• • • .' .. .' .' .
·
·
..
.'
,

'

,

,,
,

,,
,

,

,
,

,,,
,
,

,

'

'

•

I
I
I
I

.,

,

.e:
I ••

•,
:-,

'.'

·,,, ·,,

..,.

,,
, Ie:
,, ,,,,,, ,,•••,,, ,, ,, ,,, ,,,, , ,'.':.:.,.,.
.:-:.:,'.', ,, ,, ,, ,, ,•
,
,, ,

:-:
, ,

·
.,
.,., .,.,.:· .,.,.:
:.:
.,.'
· :..
.'
• :.:
'
.
. .'· · · · ·· · . . ·· .
·•,,,,'.',,,

,'.',

,•

, ,

, ,
,, ,, ,,

, ,'.',
•

, ,,

I

,
,, , ,,, , ,,, ,,,:.: :.

~.:

941.

I

Lower and Middle Triassic radiolarians from central Japanb.m.c. (0)Pn Pnchert (E)

Pn

Pn

Tc

I

I

siliceous sh.. b. m. c.

Pn

Pn

I s.)

chert

1189

I b.

chert

Tc

P~~~~~~~~~~~nnn~nn~~~~~~~~~~~~~~~~p~~~~~nnn~npp,.,.

~~~~aM

,, ,,

I
I
I
I

'.'.

.e,e,
I
I
I

lei
I
I
I
I

_, lei ,e
I
I
I
'e

, ,
,,'.',,
,, ,,

I

I

1

I

I

I

lei

I

I

I

I

I

I

I

I
I

I
I

I
I

I
I

I
I

I

I

I

I

I

I

I

.'.'..:.:.:
lei

I

I

..

:.:

:.:.

I

I

I

I

I

I

I

I

I

I

'e

I
I

'

I

I

I

lei

... '.

I

,.'

I

:.

I

: ::

.,

1

lei

.,

I

1

I

I

I

I

,e

I

I

I

1

I

I
I

.'
I

I
f

I
I

I
I

I
I

I
I

I
I

I
I

I
I

I
I

I

I

I

I

I

I

J

I

I

I

I

I

I

I

I

I

I

I

I

I

I

:.:

I

I

I

I

I

I
I

I
I

I
I

,, ,, ,,,, ,, ,,,, ,, ,,
, , ,

I
I

:e'. e'e' 'e' •• 'e'

:

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

'
.
.' '. . '.'... :.'.
,.,

.. ..
I

I

I

,,
,,
'
,
, , '

,
,,,
I

I

I

, , , ,
: :.: .:, :, ,,, ,,,'.',, ,, , ,:. :.:,.'e , , , ,

I

I

I

,, ,,
lei I
, lei .e •••• I.e,
,, ,,
:
:
::
::
,
'e
.', ,,'e ,,, ,,,, ,, ,, :e e:e: , ,
,
,
,
,
, , ,
. 'e'
,,, ,,,e::e: .: : :, :.
, ,
,
e'
I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

•

..

I

'I

,...

: :.:. :.:.:.:.
, ,
, ..•
I. "
.e.e,e.e e·e·e·e·e e .. e.. e e.e. 'ele e'e. .
.,e ,.• .• ,e.e ,.• •.•.•. e.e,, .• ••,, ,, , , . ,: : :: : :e:_:e.: : : :. : :e:••"I.',,e.e.e
•..
,
, , ,
,, ,,
:-: : : .: : :: :::: ::::

...

I

I

'

I
I

•

I

.,

" .

.,

'I

,

It'

'.
I

,
,

,
,

,'.', ,

.,

I

,

'.
•
t
t

I'

..

I

I

I

,

,.

••

' •••

I

•

••

,.

'.'

' .

I

, , 'e'.
:.::.:• •

I'e.
• ,I lI e IIII

: : :.'.: •• :.: :.:. _:_:_:e' .' :.:: :: : ::::-:: :-: :::: :.:: :: : :::: ::I :-:.
Ie,. e,e,e,e'e' 'e' • • '
:
I
'e I

,
I Ie'.
,,, : : .: : :.:.
'e'.

"
"
"

, , ,
,, ,, ,,
, , ,

I

:.

: : : .:.:.:.:
I

"

I

I

.:.:

......

.~

I: : : :.
'e'.:, ,:_ e'e:_:_:_ : : :.:
, ,

, ,

, ,,
, ,
,,, ,,,,,, ,,,
,, ,,
,, ,,
,'.''
,, ,,
,,, ,,,, ,• • ~~~~~~aM~~~~GW~~g~~$g~~OO~~~~~~~~~~nnn~~

I

I

•

.

•

I

••

•

••

,, ,, ,,:.:
, ,, :,,, ,,, ,,,,, ,,,
, ,
1

•

::
:::
, , ,
.:, :.:, ,' • • • • '.'

, ,

I

••

'I"

,

I'

I.

I'

.,..

•

I
I

••
••

'I
I.

I
I

I

'I"

".".

I

•

,

••

I

I

, ••

I

•

I

•

I

'

,

'.

I

••

I
,

.'

:.:. :.:.:.: •• :.:.:.:. , . ,. :.:.:e:. :e: :.: •• : : :: : • I' " ' .
:: :::: :::: :.:,.,e,.,.
:e:. : : :: :::: :::: : : :: :: :e: .: , ,.e.e e,e .•. e .•• : . . . . . . . .
.e .• :•.• e.e, •. e.• e,e.e,e .• e. , .e,. e.e.e. : ,, ,'.',:_:_•.• ·e·_·.::e:_:e:.
e: :_:_: ,, ,' ,,, ._ .:.:.:.:_, . ,e,e .:.:e::.
._,.,e e:.:.:e:e,e .. e. e:e:'" :e: : :,, :e:e,,, ,,, ,,, ,,,,, ,, ,,,
: : .: : : :e e:::·::::e:e:e:e e:e: :e: e: : :: :, ,,,.'e e' 'e':.:_ .:.:.:e:. e:_:e:e:.::e:e:.:e
e:.:.:.:e e:e: : :e e: :, :.::, :, ,,, ,,, .:, :, :,,,, ,:: :::: :.:::_::.: : : e: : :: :::: : ,, ,, ,, ,, ,, ,, ,, .: ,.,.e' _... ,e •. e,e, ' . .
lei ,e'e e'e' .. ,.,' . , , , , , , , , , ,,, ,,, , , , , ,, ,,, , ,.e. ,•.• ,,, ,, ,,,, ,, ,,
e:, :, :, :.
,, ,, ,, :.
,, ,, , ,
• ,.•
I
'
"
,
.
.
.
"
I
'
"
,
,
,
, , ,
:.:
I'"
'.' ••••• , . I'
'I"
"
,
,
,
,
,
,
,, ,, ,,,,'e e,.'.'.'. . , ' I" ' . ' e'.' .. e: : :
'.'
, , ,
, , " ,,.1.'I • • '.' , 'e . , I I. I lei'e'", , ,, , Ie'I''I"'.' '.':. : : :: : '.'Ie:.
:.: :.:.:.:. .:e'e:: :.:.' .: : :. ,::: :::: ,, ,, ,,,'e'I"'. ::_:. 'e:, ,: 'e .: : Ie'. e'e' :.:_ .'.'e'.,, , , ,
,,
, ,
,, ,,
:, '.:,, ,~ ~ ~.
,.' , , : ::•

l'

•• _

I

,

.,

'I"

••

,, ,,
,, ,,
,, ,,,
, ,
,
,,,
,,
,,
,,

:.

_' ••

:
,

••

I

..

•

• ,e.

,
,

,

I

I

•

•••

:.: :.:: : :e'

,••••
, ,
:-:
, , :,,, ,, ,,, , ,,, ,, ,,, , ,,,, ,,, ,,,.'.' ,.

" . '

,

I

,

I

.'

•

I
I

:
I

I'
.,

,

.,"

l

I

,,
,
,,

:., ,

,, ,,
,.'
,, ,,
,,, ,,,

I

I..
'.'.'.'..'.
..

,, , ,'
I

••

I

.'"

....

I'

I'"

'.' • • ',, ,, ,,,, ,, ,,:, :.:, ,,,, ,,, ,,,, ,,,
, ,
,, ,,

'.

, ,
,, ,,
, ,
,,, ,,,

I

I

,.

I.

"

""

I

,.

I

I.

..

.'.'.'

,
,

.'

.'

,, ,,
, ,
,,, ,,,
, ,

. .'

,,
,, ,
, ,
,,, ,,,,,, ,,,,, ,,, ,,,, ,,,.',,,,, ,,,, ,,, ,,, ,,,
,
,,,
,

•

:••:

,, ,,
,, ,,
,,, ,,,

I.'.'.',, ,,,,, ,,,

:.'.
,, ,,
, ,

:.:.
, ,
,,

.'

,

,
,,Ie:,,
, ,

, ,

,,

"
"
"

,
'
, .,

II

..

, : :

,
I

,
,

, ,

,
• .

'.'.
I
,

I
•

Kazuhiro Sugiyama

1190

suda and Isozaki (1982) reported successive
occurrence of Anisian radiolarians in a bedded chert sequence in the Kamiaso area, Gifu
Prefecture. It seems that early AnisianTriassocampecoronata

"

'0

."

:E
u

Hozmadia
gifu.ensis'"'"<::a:I-

1::::::::::::=:1 .............. .........
:;;

;:
0
..J

PIT
:;;

z
<::
::;;

0.
0.

::::l

Follicucullus
scholasticus

a:
w
Q.

~

."

"
'0

F. m onacan thus:E

(after Ishiga, 1986)

siliceous sh. toblack muddy chert
black sha lebedded chert
siliceous sh. to chert(similar to "Toishi-type" sh.)Figure 7. Schematic illustration showing
reconstructed stratigraphy of the route A.

radiolari a ns from their Samples A to E, datedby conodonts, are similar to the component
species of the Hg assemb lage.
Triassocampe coronata (Tc) assemblage
This assemblage is characteri zed by abun dant occurrence of Triassocampe coronata
Bragi n and T. myterocorys sp. nov. Other
characteristic species are Hozmadia gifuensis
sp. nov ., Triassocampe sp . afr. T. diordinis
Bragin , Spongosilicarmiger most/eri sp. nov.,S. scabiturritus sp. nov. , Eptingium manfredi
Dumitrica, Pseudostylosphaera compacta(Nakaseko and Nishimura) , P . sp. A,
Cenosphaera clathrata Parona , Oert/ispongus
diacanthus sp. nov. and Plafkerium (?) antiquum . The occurrence of Pou/pus nakasekoi, Tetrarchip/agia spp., Parasepsagon variabi/is (Nakaseko and Nishimura) , Archaeosemantis cristianensis Dumitrica andParentactinia nakatsugawaensis is common
to rare. As accessory constituent species
Entactinia (?) sp. and Astrocentrus pulcher
Ko z ur and Mostler have been obtained fromsome samples. Moreover, indeterminable

(a)

(b)

AD

Figure 8. Schematic illustrations of internal spicule in na ssellarian cephal is. (a): Lateral view . MB =medi a n bar, A = apical ray (spine), D = dorsal ray (spine) , L = primary la tera l ray (spine) , I = secondary la tera lray (spine) , V =vertical ray (spine), Ax = ax ial spine. (b): Oblique dorsal view with arches connecting ra ys.
Fo r example, AV mea ns a n arch connecting A and V. Other arches a re a bbreviated in the same way.

941.

Lower and Middle Triassic radiolarians from central Japan

species of the genera Triassobipedis Kozur,
Bulbocyrtium Kozur and Mostler, Eonapora
Kozur and Mostler and Archaeosemantis
pterostephanus Dumitrica were also obtained
from a few samples not treated in this study.
This assemblage is easily distinguishedfrom the T. de we veri assemblage of Yao(1982) by the absence of T. de we veri, Yeharaia eleaans Nakaseko and Nishimura and soon. Co-occurring conodonts represent the
Neogondolella bu1garica assemblage of Koike(1981). Thus it is clear that the age of thisassemblage ranges at least from middle to lateAnisian. In addition, the following facts canbe pointed out: (1) Mizutani and Koike(1982) reported the occurrence oflate AnisiaQ
radiolarians containing T. de we veri (described as T. sca1aris) in bedded chert beds
distributed in the Unuma area approximately
15 km east of Mt. Kinkazan. (2) The component species of this assemblage are similar to
middle Anisian radiolarians from Samples F
and G of Matsuda and Isozaki (1982). (3) The
Tc assemblage is accompanied by a large
amount of detached oertlispongid spines.
However, strikingly bent spines of Oertlispongus inaequispinosus Dumitrica, Kozur andMostler, 1980, and Falcispongus calcaneum
Dumitrica, 1982a, which are late Anisian toearly Ladinian indexes according to
Dumitrica (1982a), are never present. On thebasis of these facts, it is concluded that theage of the Tc assemblage is middle Anisianand older than the T. deweveri assemblage.

Systematic Paleontology
Descriptive terminology of nassellarian
cephalic elements is given in Figure 8. It isalso adopted on some entactinarian species.
Specimens described in this paper are deposited in the Department of Earth and Planetary
Sciences, School of Science, Nagoya University (ESN).
Class Radiolaria
Order N assellaria

1191

Family Plagiacanthidae Hertwig, 1879,
emend. Petrushevskaya, 1971
Gen us Tetrarchiplagia Dumitrica, 1982c
Type species.- T. arboressens Dumitrica,
1982c.

Tetrarchiplagia simplex Sugiyama, sp. nov.
Figures 9-1 a, 1b

Description.-Eight spines arising from theends of MB, constructing an extremely
spicular form. A, D and two L straight,
commonly with four spinules which originate
from one level. Spinules conical, variable in .
length, always unbranched. A is the longestof the eight spines. D and two L nearly
equal in shape. Thickness of these fourspines either uniform or somewhat increasing
to the level of spinules beyond which theyrapidly taper. V straight, without spinules,
distally tapering, much thinner than A, D and
two L. The two I and Ax are present butvery short. Arches completely absent.
Remarks.- This species is distinguishedfrom previously known species of the genus
by the character of spinules which are conicalin shape and originate at one level.
Dimensions (in ,um).-Based on 46 specImens. Length of A; 65-95. Length of D ;30-60. Length of L ; 30-60. Length of V; 1030.
Holotype .-ESN 146126 (Figures 9-1a, 1b)from KIN 38.
Occurrence.-KIN 29, 30, 33, 34, 36, 38,40,
49, 51, 54, 56 and 108 (Pn assemblage) and
KIN 65 (Hg assemblage).
Genus Zamolxis Dumitrica, 1982c
Type species.-Z. corona Dumitrica, 1982c.

Zamolxis dumitricai Sugiyama, sp. nov.
Figures 9-2a-3b

Description.-Six spines arising from theends of MB. A, D and two L nearly equal inshape, possessing a circular cross section and1192

K azuhiro Sugiyama

941.

Lower and Middle Triassic radiolarians from central Japanone verticil at the middle. Spines gradually
increasing in thickness to the verticil andtapering beyond it. The verticil composedof four spinules of which the shorter ones areconical and the longer ones are curved
inward. The longer spinules are partly orcompletely united with others radiating fromother spines to form some arches. Secondary, delicate meshwork also developed
between them. V rod-like, without spinules,
shorter and thinner than A, D and two L. It
is almost as thick as the arches. Two I
completely missing. Ax short but distinct.
Remarks.- This species is distinguishedfrom Z. corona and Z. tardlls Dumitrica,
1982c, by possessing secondary meshwork
connecting the arches and forming a definablecephalic wall. Further the former species
differs from the latter two species in lacking asecond verticil on each spine. Stratigraphic
position of this species and T. simplex sp.
nov. is the lowest among hitherto known
plagiacanthids.
Dimensions (in ,um).-Based on 23 specimens. Length of A; 45-90. Length of D ;45-90. Length of L; 45-90.
Holotype.-ESN 146129 (Figures 9-2a, 2b)from KIN 40.
Occllrrence.-KIN 40 and 52 (Pn assemblage).
Etymology.- This species is named after
Dr. Paulian Dumitrica, Romania, in honor of
his great contribution to the study ofradiolarJans.
Family Poulpidae De Wever, 1981
Remarks.- This taxon was originallyestablished as a subfamily of Pylentonemidae
Deflandre, 1963, by De Wever (1981). However, Cheng (1986) revealed that Pylentonema~

1193

Deflandre, 1963, the type genus of Pylentonemidae, has a medullary shell, which is quite
different feature from Mesozoic monosegmented nassellarians belonging to Poulpinae.
According to his illustrations, archocyrtiids
seem to have a similar internal skeletal structure to Poulpinae, but no occurrences ofarchocyrtiid populations are known from thePermian. Thus one can conclude that those
Paleozoic and Mesozoic mono segmented nassellarians are homeomorphic forms. Takern ura (1986) referred poul pins to the Cenozoic family Acanthodesmiidae Haeckel, 1862,
also having a sagittal ring in the skeleton. In
my opinion, however, it is much more suitable to raise the original Poulpinae to family
rank since it is not known from the Upper
Cretaceous.
Genus Hozmadia Dumitrica, Kozur
and Mostler, 1980
Type species.-H. reticlilata Dumitrica,
Kozur and Mostler, 1980.

Hozmadia ozawai Sugiyama, sp. nov.
Figures 9-4a-5

Description. -Cephal is hemispherical tosubhemispherical, with an apical spine andthree feet. MB is situated approximately inthe lower third of the cephalis, from the endsof which arise A, D, two L, two I and V.
Cephalic wall commonly thin, fragile, withpores irregular in shape, size and arrangement, and with well expressed arches outside
it. The wall is rather thick near the basewhich is circular in shape and rimmed by two
AL and LL. The cephalis of immature or
partly dissolved individuals defined only by

Figure 9. la, Ib: Tetrarchplagia simplex sp. nov., ESN 146126, holotype, KIN 3S. 2a-3b:
Zamolxis dllmitricai sp. nov. 2a: ESN 146129, holotype, KIN 40. A is broken off. 2b: Enlargement ofMH, oblique basal view. 3a: ESN 146127, paratype, KIN 40, oblique basal view. 3b: Dorsal view. 4a5: Hozmadia ozawai sp. nov. 4a: ESN 146112, holotype, KIN 40. 4b: Basal view. Sa: ESN 146113,
paratype, KIN 50, ventral view. 6-8: Hozmadia gifllensis sp. nov. 6: ESN 146119, holotype, KIN 61.
7: ESN 146117,paratype, KIN 61. 8: ESN 1461IS,paratype, KIN 61. Scale bars: Iband2b=20,um;
others = 50 ,u m.

K azuhiro Sugiyama

1194

imperfect arches with loose, secondary meshwork. Apical spine aligned with A, rodlike, with circular cross section, acute indistal portion, and commonly long. Threefeet extending from two Land D, connectedwith the collar edge, divergent approximately
45' downward below the horizontal, gently
curved inward from the middle to distal part.
They are also circular in cross section. The
apical spine and feet sometimes bladed at themost proximal part. The two I and V connected with the cephalis above the collar
edge.
Remarks.- This species is distinguishedfrom previously known species of the genus
by having rodlike apical spine and feet, andits fragile cephalic wall. The variation of thedevelopment of cephalic wall is, however,quite wide in a population from one sample.
Dimensions (in ,um).-Based on 30 specimens. Height of cephalis; 60- 100. Widthof cephalis at the base; 60-90. Length of
apical spine; 45-65. Length offoot; 60-95.
Holotype.-ESN 146112 (Figures 9-4a, 4b)from KIN 40.
Occurrence.-KIN 6, 20, 21, 29, 30, 32, 33,
35-40, 49-52, 54-57, 100, 108 and 109 (Pnassemblage).
Etymology.- This species is named inhonor of Dr. Tomowo Ozawa of Nagoya
University, whose help and continued encouragement have contributed to this study.

Hozmadia gifuensis Sugiyama, sp. nov.
Figures 9-6-8

Hozmadia (?) sp. A-Y ao, 1982, pI. I, fig. 15.
Saitoum (?) sp.-Y ao et a/., 1980, pI. I, fig. 7(?) Hozmadia cf. reticu/ata Dumitrica, Kozur andMostler-Bragin, 1991, p. 97, pI. I, fig. 7(?) Hozmadia (?) sp. -Matsuda and Isozaki, 1982, pI.
3, figs. 29, 30.
(?) Hozmadia sp. -Bragin et a/., 1988, pI. 2, fig. 2.

(?) Pou/pus (?) sp. -Kido, 1982, pI. 2, fig. 9.
(?) Pou/pus sp. A-Cheng, 1989, p. 148, pI. 5, fig. 10.
(?) Nassellaria I-Sato et a/., 1986, pI. I, fig. 4.

Description .-Cephalis subhemispherical,
usually constricted at the base, with an apicalspine and three feet. Cephalic wall thick,rugged, pierced by a large number of circular
to oval, sometimes irregularly shaped poressurrounded by polygonally shaped frames
which bear small nodes at the junctions. On
the cephalic surface arches are traceable.
Collar edge, whose diameter is approximately
half the equatorial portion, is marked by acircular to subtriangular thick peristome.
Spicule construction as with the genus.
Apical spine commonly stout, tapered, variable in length. Its proximal part is more orless bladed and middle and distal parts are
rodlike. Feet divergent, directed approximately 45' downward below the horizontal;
their proximal part solid and three-bladed;
middle part bladed or non-bladed; and distal part circular in cross section, tapered, andmore or less curved inward. The feet incontact or not with the base of cephalis.
They may arise above the collar edge when
their blades are weakly developed.
Remarks.- The present species is distinguished from H. ozawai sp. nov. by having
solid cephalic wall and prominent blades on
the proximal part of the apical spine and feet.
Immature or dissolved individuals of thisspecies are, however, somewhat similar to thelatter species. They can be distinguished by
the position of feet, namely many specimensof H. gifuensis sp. nov. have them above thebase of cephalis in such cases. This species
differs from H. rotunda (N akaseko and Nishimura, 1979) in lacking blades on the distal
part of the apical spine. Moreover, theapical spine of H. gifuensis sp. nov. is less~Figure 10. la-2b: Pou/pus nishimurae sp. nov. la: ESN 146121, holotype, KIN 38. Ib: Basalview. 2a: ESN 146123, paratype, KIN 56. 2b: Basal view. 3a, 3b: Pou/pus nakasekoi sp. nov., ESN
146124, holotype, KIN 65. 4-Sb: Tripedocorbis sp. A. 4: ESN 146132, KIN 38. Sa: ESN 146130, KIN
38. Sb: Basal view. 6a-7: Triassobipedis (?) aetoides sp. nov. 6a: ESN 146148, holotype, KIN 50,
lateral view. 6b: Basal view. 7: ESN 146147, paratype, KIN 49, dorsal view.

941.

Lower and Middle Triassic radiolarians from central Japan

11 95

K azuhiro Sugiyama

1196

developed than that of the latter species.
One can regard this species as an intermediate
form between H. ozawai and H. rotunda, andall of them possibly represent one and thesame species through time. As it is difficult
to prove such a fact for the present, detailed
studies are necessary to solve the problem.
This species differs from H. reticulata inhaving a rather slender apical spine andthree-bladed rather than four-bladed feet.
Dimensions (in ,um).-Based on 35 specimens. Height of cephalis; 100-140. Widthof cephalis at the equatorial portion; 105150. Width of cephalis at the base; 70-100.
Length of apical spine; 70-130. Length offoot; 75-135.
Holotype .-ESN 146119 (Figure 9-6)
from KIN 61.
Occurrence.-KIN 58-62, 64-68 (Hg assemblage) and KIN 44, 69, 71 and 73 (Tc assemblage).
Etymology.- The name is derived from
Gifu City, type locality.

two Land D, nearly straight, diverging
approximately 30· downward from the horizontal, not bladed, three-pronged distally. V
extending to the collar edge, and prolonged
into a conical spine.
Remarks.- This species is similar to P.
hirsutus De Wever, 1982, in the general shape.
The former, however, differs from the latter inlacking bladed feet and having branches evenon the apical spine.
Dimensions (in ,um).-Based on 18 specimens. Height of cephalis; 40-70. Widthof cephalis at the base; 65-90. Length of
apical spine; 45-65. Length of verticalspine; up to 35. Length of foot; 35-65.
Holotype .-ESN 146124 (Figures 1O-3a,3b) from KIN 65.
Occurrence.-KIN 65 (Hg assemblage) and
KIN 42, 44, 45, 65 and 69 (Tc assemblage).
Etymology.- This species is named inhonor of Prof. Kojiro Nakaseko, the leading
person of radiolarian study in Japan.

Poulpus nishimurae Sugiyama, sp. nov.
Genus Poulpus De Wever, 1979
Type species .-P. piabyx De Wever, 1979.

Poulpus nakasekoi Sugiyama, sp. nov.
Figures 10-3a,3b

Description.-Cephalis subhemispherical,
relatively small, with an apical spine andthree feet. Cephalic wall perforate, more orless rough, with small nodes and arches wellmarked. Apical spine thin, rodlike, having
one verticil of three conical spinules at the
middle or distal part. MB lying in the baseof cephalis. D, two L and two I connectedwith the collar edge. Three feet arising from~

Figures 10-la--2b

Description.-Cephalis subhemispherical,
with an apical spine and three feet. Cephalicwall incomplete, generally defined by archeswith loose, secondary meshwork. MB lying
in the base of cephal is. Apical spine rodlike, with pointed end, variable in length,
extending from A. D, two L and two I
connected with the collar edge. Three feetlong, gently curved inward, diverging approximately 45· to 60· downward from the horizontal, not bladed, with pointed ends, arisingfrom the two Land D. V tied to the base of
cephalis, prolonged or not into a conicalFigure 11. 1-3b: Triassocampe myterocorys sp. nov. 1: ESN 146133, holotype, KIN 45. 2: ESN
146287, paratype, KIN 45. 3a: ESN 146136, paratype, KIN 45. 3b: Enlargement of the proximal part.
C=cephalis, T=thorax, A=abdomen. 4,9: Triassocampe (?) sp. A. 4: ESN 146144, KIN 65. 9: ESN
146145, KIN 68. 5,6: Triassocampe coronata Bragin, 5: ESN 146137, KIN 45. 6: ESN 146138, KIN
45. 7,8: Triassocampe sp. aff. T. diordinis Bragin. 7: ESN 146142, KIN 45. 8: ESN 146141, KIN 45.
10-12: Spongosilicarmiger scabiturritus sp. nov. 10: ESN 146162, holotype, KIN 45. 11: ESN 146161,
paratype, KIN 45. 12: ESN 146163, paratype, KIN 50. 13,14: Spongosilicarmiger mostlen sp. nov. 13:
ESN 146160, holotype, KIN 45. 14: ESN 146159, paratype, KIN 45. Scale bars: 3b=20 p'm; others=
50 p.m.

941.

Lower and Middle Triassic radiolarians from central Japan

11 97

K azuhiro Sugiyama

1198

SpIne.

Remarks.- This species is easily distinguished from the previously known species of
the genus by having rodlike apical spine andfeet, and incomplete cephalic wall.
Dimensions (in ,um).-Based on 22 specimens. Height of cephalis; 50-75. Widthof cephalis at the base; 65-85. Length of
apical spine; 45-80. Length of verticalspine; up to 30. Length of foot; 50-120.
Holotype .-ESN 146121 (Figures 1O-la,1b) from KIN 38.
Occurrence.-KIN 34, 37, 38 and 40 (Pnassemblage).
Etymology.- This species is named after
Dr. Akiko Nishimura in honor of her great
contribution to the study of Mesozoic andCenozoic radiolarians.
Family Ruesticyrtiidae Kozur
and Mostler, 1979
Genus Triassocampe Dumitrica, Kozur andMostler, 1980
Type species.- T. scalaris Dumitrica,
Kozur and Mostler, 1980 (a junior objectivesynonym of Dictyomitrella deweveri N akaseko and Nishimura, 1979).

Triassocampe myterocorys Sugiyama, sp. nov.
Figures 11-1-3b(7) Triassocampe (7) sp. G-Y ao, 1982, pI. 1, fig. 7.
-Matsuda and Isozaki, 1982, pI. 3, figs. 1-3, 2024.-Arakawa, 1986, pI. 5, figs. 1-3.

Descnption.-Cephalis very small, imperforate, conical to hemispherical, having anapical spine which is conical and often
obliquely directed. Collar stricture is commonly visible, but far shallower than following ones. Thorax wider than cephalis,
hemispherical, nodulated, usually pierced bysmall pores irregularly arranged. Abdomen
and the fourth segment barrel-shaped, wider
than thorax, with many pores scattered oraligned in transverse rows, and usually lacking the development of circumferential ridge.

Length of abdomen variable, either longer or
shorter than the fourth segment. Width ofabdomen more or less narrow than the fourth
segment. The fifth segment has morphologic
similarity either to the fourth or sixth one. It
sometimes has fairly intermediate features
between them. The sixth and all the subsequent segments subtrapezoidal in outline,with circumferential ridges just below constnctlOns. The circumferential ridges
become prominent distally. Pores variablefrom circular to polygonal in shape, usuallyaligned in one or two transverse rows below
each circumferential ridge. They are sometimes arranged without any regularity.
Remarks.- This species resembles T.
multinerforata (Kozur, 1984) in the morphology of thorax, abdomen and the fourth segment. The former is, however, distinguishedfrom the latter by lacking a stout, bladed
apical spine. Morphologic variety of thisspecies is very wide.
Dimensions (in ,um).-Based on 47 specimens. Length of apical spine; up to 25.
Height of cephalis and thorax; 30-45.
Width of thorax; 30-45. Height of abdomen; 15-30. Width of abdomen; 40-60.
Height of fourth segment; 25-35. Width offourth segment; 55-75. Height of fifth segment; 20-35. Width of fifth segment; 6080.
Holotype.-ESN 146133 (Figure 11-1)
from KIN 45.
Occurrence.-KIN 41,42,44-46,69, 70 and
73 (Tc assemblage).

Triassocampe coronata Bragin
Figures 11-5,6(7) Dictyomitrella sp. A-De Wever in De Wever et al.,
1979, p.90, pI. 5, figs. 12, 16.
Triassocampe (7) sp. aff. T. sp. A of Yao (1982)-Matsuda and Isozaki, 1982, pI. 3, figs. 4-9.Arakawa, pI. 5, figs. 5-7.
Triassocampe sp. A-Takashima and Koike, 1982, pI.
\, figs. 3, 4.-Kojima and Mizutani, 1987, p.265,
fig. 3; 1.
Triassocampe deweveri (Nakaseko and Nishimura,

941.

Lower and Middle Triassic radiolarians from central JapanI979)-Nishizono el al., 1982, pI. 3, fig. I3.(?)
Triassocampe dewel'eri-Kishida and Sugano, 1982, pI.
1, fig. 10.
Triassocampe coronala Bragin, 1991, p.99, pI. 1, fig.
15.

Description.-Cephalis dome-shaped, imperforate, larger than that of T. myterocorys
sp. nov. It sometimes bears a weak, wart-likeapical spine. Collar stricture almost indistinct outside. Thorax barrel-shaped in outline, either imperforate or pierced by scatteredsmall pores, more or less wider but shorter
than cephalis. Lumbar stricture slightly visible. Abdomen barrel-shaped to subtrapezoidal in outline, wider than thorax, nodose,
pierced by scattered or somewhat arranged
pores, without circumferential ridge. Eachpostabdominal segment subtrapezoidal in
outline, with imperforate stricture, nearly
uniform in length and width, having welldeveloped circumferential ridge in the upper
portion. Those circumferential ridges
become prominent in the distal segments. A
single row of circular pores situated justbeneath each circumferential ridge.
Remarks.- This species is distinguishedfrom T. myterocorys sp. nov. by the charactersof cephal is and pore arrangement. It resembles T. deweveri in the cephalic feature but
differs from the latter in having only a single
row of pores beneath each circumferential
ridge.
Dimensions (in J.lm).-Based on 35 specimens. Length of apical spine; up to 5.
Height of cephal is, thorax and abdomen; 6585. Width of abdomen; 55-65. Height offourth segment; 20-35. Width of fourth segment; 55-75. Height of fifth segment; 2035. Width of fifth segment; 55-85.
Occurrence.-KIN 41-46, 69-73 (Tc assemblage).
Triassocampe sp. aff. T. diordinis Bragin
Figures 11-7, 8
aff. Triassocampe (?) sp. aff. T. sp. H of Yao (1982)Matsuda and Isozaki, 1982, pI. 3, figs. 12-15, 17-

1199

19.
aff. Triassocampe diordinis Bragin, 1991, pI. 1, fig. 8 ;pI. 9, fig. 4.

Remarks.- This species is typically characterized by having' a single row of pores justbeneath the poorly developed circumferential
ridges. However, the features is so variable
that the species is possibly conspecific with T.
diordinis.
Occurrence.-KIN 45 (Tc assemblage).
Triassocampe (?) sp. A
Figures 11-4, 9Remarks.- The test is formed of many,
usually more than five, barrel-like segments
and a short apical spine may be present on the
cephal is. The occurrence is relatively common in the Hg assemblage, but completely
preserved specimens have not been obtained
yet and the details of pore features are at thepresent time not well understood. The general shape is somewhat resembles T. my terocorys sp. nov. but differs from the latter inlacking prominent circumferential ridges.
Occurrence .-KIN 60, 62, 64-66 and 68(Hg assemblage).
Family Silicarmigeridae Kozur
and Mostler, 1980
Genus Spongosilicarmiger Kozur, 1984
Type species.-S. italicus Kozur, 1984.

Spongosilicarmiger mostleri Sugiyama, sp. nov.
Figures 11-13,14

Description.- Cephalis subhemispherical,
imperforate, with rugged surface, sometimes
pierced by very small pores irregularly scattered. Apical spine composed of three parts;
distal part rodlike, tapering, nearly straight;
middle part porous, formed of four or more
longitudinal ridges connected by transverse
bars; proximal part robust, imperforate, rugged, probably hollow. Three feet long, thin,
rodlike, arising from the collar strictureKazuhiro Sugiyama

1200

which is usually hidden by spongy fabric or
granules, and connected with the transverse
ridges on thorax and postthoracic segments
through several thin bars. The postthoracic
segments long, nearly cylindrical, spongy,
with numerous small pores.
Remarks.- This species is distinguishedfrom S. italic us by its long and slender apicalspine. The middle of the apical spine of theformer species is homologous with that of thelatter which is characterized by marked
expanding.
Dimensions (in ,llm).-Based on 17 specimens. Length of apical spine; 180-230.
Thickness of apical spine in distal part: 1520. Thickness of apical spine in proximal
part; 25-35. Height of cephal is; 50-80.
Maximum width of cephal is ; 60-80.
Length of foot; 90-270.
Holotype.-ESN 146160 (Figure 11-13)
from KIN 45.
Occurrence.-KIN 44, 45 and 69 (Tc assemblage).
Etymology.- This species is named after
Dr. Helfried Mostler, Austria, in honor of his
great contribution to Paleozoic and Mesozoic
micropaleontology.

Snongosilicarmiger scabiturritus Sugiyama
sp. nov.
Figures 11-10-12

Description.-Cephalis subhemispherical,
rugged, pierced by numerous small pores, andhaving a robust apical spine. Apical spine.
usually subvertical; proximal to middle partporous, rugged, probably hollow; distal part
conical, rapidly tapered to a point. Threefeet extending from the base of cephalis may
be prolongations of D and two L. Thorax
and postthoracic segments hemmed by feet,rugged, porous, gradually increasing in thewidth distally, and often bearing transverse
ridges.
Remarks.- This species resembles S. nakasekoi Yeh, 1990, from which it differs inhaving perforated and rugged cephalic wall.

Dimensions (in ,llm).-Based on 31 specimens. Length of apical spine; 60-120.
Height of cephal is ; 60-90. Maximum widthof cephalis; 65-90. Length offoot; 35-100.
Holotype .-ESN 146162 (Figure 11-10)
from KIN 45.
Occurrence.-KIN 41, 44, 45,69, 70 and 72(Tc assemblage).
Family Tripedurnulidae Dumitrica, 1991
Genus Tripedocorbis Dumi trica, 1991
Type species.- T. ramulispinus Dumitrica,
1991.

Tripedocorbis sp. A
Figures 10-4-5b

Description.-Cephalis subhemispherical,
with an apical spine, three feet and a shortvertical spine. Cephalic wall fragile, piercedby circular to subcircular pores which are
randomly arranged. Density of the poresvariable among specimens. The base of the
cephalis not in a plane, rimmed by two Dt,
two Lt, two LV. LL missing. Apical spine
needlelike, nearly straight, arising from A,
and obliquely directed. V directing approximately 4Y upward from the horizontal, having a point contact with the base of the
cephalis, and forming an acute spine beyond
it. Three feet extending from D and two L,
typically rodlike, straight, more or less tapering distally, and directing approximately 4Yor more downward from the horizontal. In
some specimens proximal part of each foot isslightly bladed, then the blades are connectedwith others on neighboring foot by arches.
Remarks.-Although Dumitrica (1991)
defined the genus as one not having threebladed feet, the details of the proximal part of
the feet were often unobservable in my materials due to the poor preservation. Thus
some individuals having relatively thick feetpossibly belong to the genus Baratuna Kozur
and Mostler, 1981. This species resembles T.
blomei Dumitrica from which it differs in941.

Lower and Middle Triassic radiolarians from central Japan

1201

lacking thorns on the feet.
Dimension (in ,um).-Based on 25 specimens. Height of cephalis; 45-70. Widthof cephalis at the base; 40-60. Length of
apical spine; 20-45. Length of foot; 10-20
Occurrence.-KIN 2, 6, 14, 21, 29, 33-36,
39,40,47-50,52-54,56,97-100 and 108-111(Pn assemblage) and KIN 58 (Hg assemblage).

5b) from KIN 37.
Occurrence.-KIN 34, 37, 40 and 56 (Pnassemblage) and KIN 58, 60 and 65 (Hgassemblage).
Etymology.- This species is named afterDr. B.K. Holdsworth, University of Keele,
England, in honor of his great contribution
to the study of Paleozoic radiolarians.

Incerta Family

Genus Nofrema Dumitrica, Kozur
and Mostler, 1980
Type species.-N. trispinosa Dumitrica,
Kozur and Mostler, 1980.

Genus Hinedorcus Dumitrica, Kozur
and Mostler, 1980
Type species.-H. alatus Dumitrica, Kozur
and Mostler, 1980.

Hinedorcus holdsworthi Sugiyama, sp. nov.
Figures 12-5a,5b

Description.-Cephalis small, subhemispherical to hemispherical, poreless or pierced
by a small number of nearly circular, small
pores, having an apical spine and three feet,with or without a vertical spine. Apicalspine well developed, rodlike to conical,
tapered to a point. It is usually obliquely
directed, nearly straight or gently curved
upward in proximal part. Vertical spine isvery short, generally vestigial, and surrounded by small pores at the base, when it ispresent. Three feet directed downward, rodlike, probably extending from D and the twoL, arising from the collar stricture, and amalgamated with thoracic wall at the proximal to
middle part. Thorax long, barrel-shaped,with scattered, small, circular to irregularly
shaped pores.
Remarks.- The skeletal structure could
not be confirmed at this time. This species
differs from the type species in its rodlike
apical spine and feet.
Dimensions (in ,um).-Based on 15 specimens. Length of apical spine; 25-45.
Height of cephalis; 35-45. Maximum widthof cephal is ; 30-50. Length of foot; 40-80.
Holotype .-ESN 146158 (Figures 12-5a,

Nofrema (?) gigantoceras Sugiyama, sp. nov.
Figures 12-1-3

Description.-Cephalis large, porous, subhemispherical, with a stout, long apical spine.
Cephalic wall rugged, pierced by many small
pores. Arches sometimes faintly visible on
it. Apical spine gently tapering distally,
directed more or less obliquely, consisting of
bladed proximal part and rodlike middle todistal one. Thorax cylindrical, more or lessincreasing distally in width. Maximum
width of thorax generally less than that of
cephal is. Thoracic wall similar to cephalicone. Collar stricture marked externally by agentle change in contour, from which prolongations of D and two L extend downward.
They hem the thoracic wall proximally, andgradually detach from the wall to form three,rodlike feet.
Remarks.- The present species is distinguished from N. trispinosa by its much
expanded cephalis and by lacking constrictions on the thorax. This species differs fromhitherto known Spongosilicarmiger species in
its much larger cephalis. It is tentatively
assigned to Nofrema but may be an ancestralform of Spongosilicarmiger or independent ofboth the genera.
Dimensions (in ,um) .-Based on 45 specimens. Height of cephalis; 80-115. Maximum width of cephalis; 95-115. Height ofthorax; 75-120. Maximum width of tho-

1202

K azuhiro Sugiy ama

941.
rax; SO-70.

Lower and Middle Triassic radiolarians from central Japan

Length of foot; SO- 140.
146156 (Figure 12-1)

Holotype .-ESN
from KIN 61.

Occurrence.-KIN 60-62, 64 and 6S (Hozmadia gifuensis assemblage).
Genus Triassobipedis Kozur, 1984
Type species.- T. balatonica Kozur, 1984.

Triassobipedis (?) aetoides Sugiyama, sp. nov.
Figures 1O-6a-7

Description.-Cephalis elongated domeshaped, swollen in the upper half, and rather
tight in the lower half. Internal spicule composed of MB, A, D, two L, two I and V. Ax
mlssmg. MB situated approximately in thelower third of cephalis. The base of cephalis
circular in shape. Cephalic wall with circular to oval, sometimes irregularly shaped
pores disposed at random. They are usuallymuch denser in the upper half of the cephal is,whereas the peristome of cephalis is nearly
imperforate. Arches visible on the wall.
Apical spine extending from A is obliquely
directed but always situated in the sagittal
plane. It is acute, circular in cross section,
sometimes bladed at the proximal part.
Those blades corresponding to the terminals
of arches. The two L extend outside the wall
into two well-developed feet located much
above the cephalic base. They are rodlike,acute, circular in cross section, directed
obliquely downward, and situated at an angleof 120-ISO· to each other. With or without
the third foot which is vestigial and prolonged from D.
Remarks.- This species clearly differs fromT. balatonica in its porous cephalic wall andrather slender feet. Moreover, the feet of thisspecies do not contact the base of the cephal is1203

as with the latter species. It is probably atransitional form from Hozmadia to typical
Triassobipedis taking account of its generalshape and the presence of vestigial third footextending from D on some individuals. The
precise generic assignment thus remains questionable.
Dimensions (in ,um).-Based on 26 specimens. Height of cephal is; 90- 12S. Maximum width of cephal is; 7S-9S. Width of
cephalis at the base; 30-43. Length of
apical spine; SO- 7S. Length of foot arisingfrom L; 35-60.
Holotype .-ESN 146148 (Figures 1O-6a6c) from KIN SO.
Occurrence.-KIN 37, 38, 40,49 and Sl (Pnassemblage ).
Genus Zevlus Sugiyama, gen. nov.
Etymology.- The name is formed by arbitrary combination of letters, masculine gender.
Including species.-Z. yaoi Sugiyama sp.
nov. (type species) and Z. perarmatus
Sugiyama sp. nov.
Diagnosis.- Test commonly composed ofmore than two segments separated by shallow
constnctlOns. Distinct internal partltlOn
between segments absent. Cephal is commonly poreless, sometimes pierced by scattered small pores. Internal spicule has notbeen observed yet, but external two spines
which extend upward from the cephalis probably correspond to apical and vertical ones,
respectively. Apical spine always welldeveloped, more or less obliquely directed
especially in proximal part. Vertical spine
short, thin, sometimes vestigial or missing.
Thorax and the subsequent segments wider
than cephalis, having scattered pores, without
circumferential ridges. With or without

Figure 12. 1-3: Nofrema (?) gigantoceras sp. nov. 1: ESN 146156, holotype, KIN 60. 2: ESN
146288, paratype, KIN 60. 3: ESN 146157, paratype, KIN 61. 4,7: Zevius yaoi gen. et sp. nov. 4:
ESN 146152, holotype, KIN 38. 7: ESN 146153, paratype, KIN 38. Sa, 5b: Hinedorcus holdsworthi sp.
nov., ESN 146158, ho1otype, KIN 38. 6a, 6b: Zevius perarmatus gen. et sp. nov., ESN 146155, ho1otype,
KIN 37. 8, 9: Entactinia morii sp. nov. 8: ESN 146165, ho1otype, KIN 49. 9: ESN 146166, paratype,
KIN 49. Scale bars: 5b= 20.urn; others = 50 .urn.
~

Kazuhiro Sugiyama1204

other spines near the collar stricture.
Remarks.- This genus is distinguishedfrom Triassocampe by having large apicalspine and complete lack of deep constrictions
and circumferential ridge on segments. The
suprageneric assignment is not known yet.

Occurrence.-KIN 2, 34, 35, 37-40, 49, 54,
56, 100, 108 and 109 (Pn assemblage) and
KIN 58, 61 and 65 (Hg assemblage).
Etymology.- This species is named after
Dr. Akira Yao of Osaka City University inhonor of his great contribution to the study ofMesozoic radiolarians.

Zevius yaoi Sugiyama, sp. nov.
Figures 12-4,7Description.-Cephalis small, subhemispherical to hemispherical, poreless or pierced
by a small number of nearly circular small
pores, with an apical spine, with or without avertical spine, and without other spines.
Apical spine rodlike, usually obliquely directed at the proximal part, straight or gently
curved upward in the middle part, and terminated in a point. Vertical spine rodlike,directed obliquely upward, much thinner andshorter than apical one, sometimes vestigial
or miSSing. Even if it is invisible outside, theintersecting point of corresponding ray to the
cephalic wall can be inferred in most cases bya swell on the cephal is. Thorax and thesubsequent segments usually barrel-shaped,
always wider than cephalis, with many scattered pores of various size.
Remarks.- This species has a certain external morphology in common with Goestlingella illyrica Kozur, 1984. The former is, however, easily distinguished from the latter bylacking funnel-like abdomen. It also resembles Stichomitra (?) triassic a Dumitrica,
Kozur and Mostler, 1980, but differs from thelatter in having much larger thorax. Because
the internal spicule of this species has notbeen observed yet, further comparisons are
difficult to make at present.
Dimensions (in JLm).-Based on 40 specimens. Length of apical spi ne; 30- I 20.
Length of vertical spine; up to 30. Heightof cephalis; 25-40. Maximum width of cephalis; 35-50. Height of thorax; 30-50.
Maximum width of thorax; 50-70.
Holotype .-ESN 146152 (Figure 12-4)
from KIN 38.

Zevius perarmatus Sugiyama, sp. nov.
Figures 12-6a,6b

Description.-Cephalis subhemispherical,
nearly imperforate, with an apical, a verticaland two lateral spines. Apical spine rodlike,pointed, obliquely directed in the proximal
part, straight or gently bent upward in the
middle part. Vertical spine conical, directed
obliquely upward. Two lateral spines arising from just above the collar stricture arealso conical and very similar to vertical one.
Judging from the relative positions to apicaland vertical spines, they are probably prolongations of two I. Thorax and postthoracic
segments barrel-shaped, gradually increasing
in width distally, pierced by circular pores.
Pores randomly arranged, increasing in number and size distally.
Remarks.-In my material, there is only
one completely preserved specimen (holotype), on which the above description ismainly based. This species is easily distinguished from Z. yaoi sp. nov. by possessing
two lateral spines. It probably has the same
spicule construction as Anisicyrtis sp. A described by Gorican and Buser (1988/1989),
which also has four spines extending from A,
V and two I. They seem to be closely related
to one another. This species differs from
Triassocampe hungariaca (Kozur, 1984) inhaving a vertical spine, and rather short lateral spines. Moreover, lateral spines of thelatter species are prolongations of the two L,
according to the original description by
Kozur (1984).
Dimensions (in JLm).-Based on one specimen (holotype). Length of apical spine; 65.
Length of vertical spine; 25. Length of lat-

941.

Lower and Middle Triassic radiolarians from central Japaneral spine; 30. Height of cephalis; 40.
Maximum width of cephal is ; 40. Height ofthorax; 25. Maximum width of thorax; 50.
Holotype .-ESN 146155 (Figures 12-6a,6b) from KIN 37.
Occurrence.-KIN 37, 38, 40 and 49 (Pnassemblage) and KIN 58 (Hg assemblage).
Order Entactinaria
Remarks.- The order Entactinaria, generally characterized by possessing an internal
spicule and spherical shell, was proposed by
Kozur and Mostler (1982). However, many
investigators have not accepted their proposal
yet and have included this type of radiolarianin the spumellarians. It is, however, certainthat they are phylogenetically much closer tonassellarians than typical spumellarians, andshould be separated from the latter, althoughseparation at the order rank still remains
debatable.
Family Entactiniidae Riedel, 1967a
Genus Entactinia Foreman, 1963
Type species.-E. herculea Foreman, 1963.

Entactinia morii Sugiyama, sp. nov.
Figures 12-8,9Description.-Shell single, spherical, latticed, with relatively large, subcircular topolygonal pores of irregular size. Latticebars usually oval in cross section, bearing
small nodes at junctions. Immature individuals(?) have edged bars and the lattice work ismore or less imperfect. MB is eccentricallysituated in the shell, with three rays on eachend. The spicule system shows perfect triradial symmetry when one views along MB.
The rays mayor may not be prolonged into
rodlike spines. They are variable in length,
thicker than corresponding rays.
Remarks.- This species has a looser lattice
shell and simple spines compared with all
Permian species.
Dimensions (in ,um).-Based on 23 speci-

1205

mens. Diameter of shell; 110-160. Lengthof spine; up to 90.
Holotype .-ESN 146165 (Figure 12-8)
from KIN 49.
Occurrence.-KIN 40, 49, 50 and 56 (Pnassemblage ).
Etymology.- This species is named inhonor of Dr. Shinobu Mori of Nagoya University, whose help and continued encouragement have contributed to this study.
Family Eptingiidae Dumitrica, 1978aRemarks.- The suprafamily assignment is
problematic because it has both entactinarianand nassellarian features. I tentatively
include it in Entactinaria in this study
although the descriptive terminology of the
spicule system follows that of nassellarians.
Dumitrica (l978a) defined Eptingiidae as afamily possessing a sagittal ring and threespines prolonged from A and two L. In thiscase a problem arises with respect to thefamily assignment of Tetrarhopalus gen. nov.,
because it has four spines rather than three.
Except for this feature, however, it has somemorphology in common especially with
Cryptostephanidium Dumitrica, 1978a, andthey must be closely related. In this study,
therefore, the original diagnosis of this family
is tentatively enlarged to include Tetrarhopalus gen. nov.
Genus Cryptostephanidium Dumitrica, 1978aType species.- C. cornigerum Dumitrica,
1978a.

Cryptostephanidium longispinosum (Sashida)
Figures 13-1,2

Tripocyclina janonica Nakaseko and Nishimura,
1979-Blome et al., 1986, p1. 8.3, fig. 18.
Cryptostephanidium sp. A-Cheng, 1989, p. 148, p1. 6,
fig. 3.
Cryptostephanidium sp. D-Cheng, 1989, p. 148, p1. 7,
fig. 5.
Cryptostenhanidium sp. E-Cheng, 1989, p. 148, p1. 7,
fig. 6.
Cryptostephanidium (?) sp. B-Cheng, 1989, p. 148, p1.

1206

Kazuhiro Sugiyama

941.

Lower and Middle Triassic radiolarians from central Japan6, fig. 4.
Cryptostephanidium (?) sp. C-Cheng, 1989, p. 148, pI.
6, fig. II.
Spongostephanidium longispinosum Sash ida, 1991, p.
694, figs. 7-1-8.

Description.-Shell subspherical, more orless compressed, latticed, with small nodes at
the junctions of bars which form angular poreframe, and with three spines arising from A
and two L. Lattice bars circular to oval incross section. They are thin in immatureindividuals (?) and then often form rather
incomplete and nodular shell. 0, two I, V
and Ax connected with the shell wall.
Spines are acute, rodlike to conical, one ofwhich extending from A is somewhat longer
than the other two. Existence of sagittal ringpresently not confirmed.
Remarks.-Sashida (1991) assigned thisspecies to Spongostephanidium Dumitrica,
1978a. However, I have confirmed the presence of 0 which is a diagnostic feature of
Cryptostephanidium. It is notable that specimens with free sagittal ring have not beenfound so far. It is at present difficult todecide whether the absence of sagittal ring is
original or due to extracting procedure by HF
method.
Dimensions (in ,um).-Based on 19 specimens. Maximum diameter of shell; 65100. Length of spine extending from A; 45100. Length of spine extending from L; 3065.
Occurrence.-KIN 29, 30, 32-40,47-56,98100 and 108-111 (Pn assemblage) and KIN
58, 60-62, 64-67 (Hg assemblage).
Cryptostephanidium sp. cf. C. verrucosum
Dumitrica, 1978a

1207

Figures 13-3

Remarks.- This species is characterized by
its rough shell wall and proximally bladedspines, and is similar to C. verrucosum in thegeneral shape. However, it differs from thelatter species in having unequal spines ofwhich one arising from A is relatively longer.
Occurrimce.-KIN 58-61, 65 and 68 (Hgassemblage).
Genus Tetrarhopalus Sugiyama, gen. nov.
Etymology.-From the Greek tetra, four,and rhopalon, stick, masculine gender.
Type species.- T. itoigawai Sugiyama sp.
nov. (by monotypy).
Diagnosis.- Test is similar to Cryptostephanidium but differs from it in possessing
four spines prolonged from A, two Land V.
o either wartlike or completely absent. Ax
usually longer than D. Free sagittal ringpresent or absent in the shell cavity.
Remarks.- This genus is distinguishedfrom other eptingiid genera by possessing
four spines.

Tetrarhopalus itoigawai Sugiyama, sp. nov.
Figures 13-4a-6b

Description.-Shell spherical to subspherical, defined by some arches with coarse secondary latt~ce work. Small nodes often
developed at the junctions of lattice bars.
AV as with genus, delicate, fragile, muchthinner than other arches, forming a part ofsagittal ring. A, two L and V increasing
gradually in thickness to arches, and extending into four spines. Spines rodlike to conical, circular in cross section. They are variable in length, almost equal in shape, and+- Figure 13. 1,2: Cryptostephanidium longispinosum (Sashida). 1: ESN 146169, KIN 49. 2: ESN
146168, KIN 49, oblique lateral view. 3: Cryptostephanidium sp. aff. C. verrucosum Dumitrica, ESN
146172, KIN 61. 4a-6b: Tetrarhopalus itoigawai gen. et sp. nov. 4a: ESN 146175, paratype, KIN 56,
lateral view. 4b: oblique lateral view showing free arch AV pointed by arrow. 5: ESN 146173, holotype,
KIN 50, front view. 6a: ESN 146289, paratype, KIN 56, back view, focused on MB. 6b: Focused on V.
7,8: Pseudostylosphaera kozuri sp. nov. 7: ESN 146191, holotype, KIN 38. 8: ESN 146290, paratype,
KIN 49. All scale bars=50 pm.

Kazuhiro Sugiyama

1208

sometimes more or less asymmetrically arranged relative to the sagittal plane. D and Ax
as with genus.
Remarks.- The development of the shell,arches and length of the spines are quite
variable in a population from one sample.
Dimensions (in ,um).-Based on 27 specimens. Maximum diameter of shell; 70-120.
Length of spine; 20-90.
Holotype .-ESN 146173 (Figure 13-5)
from KIN 50.
Occurrence.-KIN 49, 50, 52 and 56 (Pnassemblage).
Etymology.- This species is named inhonor of Prof. Junji Itoigawa of Nagoya
University, whose help and continued encouragement have contributed to the present
study.
Family Capunuchosphaeridae De Wever,
1979
Remarks.- The family assignment of thefollowing genera follows Dumitrica (1984,1985).
Genus Parasepsagon Dumitrica, Kozur
and Mostier, 1980
Type species.-P. tetracanthus Dumitrica,
Kozur and Mostler, 1980.

Parasepsagon leptaleus Sugiyama, sp. nov.
Figures 14-4-5b

Description.- Test consisting of one cortical and one medullary shell, having fourspines. Internal spicule consisting of MB,
four basal rays and three or four apical ones.
Each end of MB with two basal rays and one
or two apical ones. Development of apicalrays commonly weak. All basal rays extending into spines. The basal rays gradually
increase in thickness from proximal verticil(corresponding to the junction of medullaryshell) to distal one (corresponding to thejunction of cortical shell). The spines are
thicker than corresponding internal rays, rodlike, tapered distally, circular in cross section,

arranged at right angles. Their proximal
part sometimes four-bladed. Cortical shelldiscoidal, formed of thin bars, often ambiguously defined. Medullary shell is also
obscure in the outline. Differentiation ofboth shells hardly recognized on poorly
preserved materials.
Remarks.-Dumitrica et al. (1980) designated that this genus is characterized by having
one cortical shell, one medullary shell andfour bladed spines. Against the definition,
this species lacks completely bladed spine andsolid shells, and these features are quite
different from previously known species of
the genus.
Dimensions (in ,um).-Based on 15 specimens. Maximum diameter of cortical shell ;60-130. Length of spine; up to 140.
Holotype .-ESN 146187 (Figures 14-5a,5b) from KIN 49.
Occurrence.-KIN 35, 37, 40,49 and 51 (Pnassemblage).
Genus Pseudostylosphaera Kozur
and Mostier, 1981
Type species.-P. gracilis Kozur and Mostler, 1981.

Pseudostylosphaera kozuri Sugiyama, sp. nov.
Figures 13-7,8

Description.- Test as with genus. Internal
spicule consisting of MB, four basal rays andthree or four apical ones. Each end of MB
has two basal and one or two apical spines.
Two of basal rays, one at either end of MB,
extending in counter directions and prolonged into equatorial spines outside. They
gradually increase in thickness from proximal
to distal verticils just like those of Parasepsagon leptaleus sp. nov. Two equatorial
spines much thicker than corresponding rays,
rodlike, tapering distally, with circular crosssection. Cortical shell ellipsoidal, formed ofloose lattice work, bearing small nodes at thejunctions of lattice bars. Medullary shell has
much looser lattice work, sometimes fairly

941.

Lower and Middle Triassic radiolarians from central Japan

indistinct.
Remarks.- This species is easily distinguished from other species of the genus by its
primitive morphologic features. Some individuals lack completely differentiated shells,
but the variation is considered to be
intraspecific. Two external spines are termed
not "polar" but "equatorial" spines just like
Cenozoic axoprunins, as discussed In
Sugiyama et al. (in press).
Dimensions (in ,um).-Based on 37 specimens. Major diameter of cortical shell; 60120. Minor diameter of cortical shell; 5090. Length of equatorial spine; 45-90.
Holotype .-ESN 146191 (Figure 13-7)
from KIN 38.
Occurrence.-KIN 29, 30, 32-40, 47-50, 52
and 54-56 (Pn assemblage).
Etymology.- This species is named after
Dr. Heinz Kozur, Hungary, in honor of his
great contribution to Paleozoic and Mesozoic
micropaleontology.

Pseudostylosphaera sp. A
Figures 14-1,2

Archaeospongoprunum sp. -Arakawa, 1986, pI. 7, fig.
2.
aff. Pseudostylosphaera sp. -Blome et al., 1986, pI. 8.
3, figs. 4, 5.

Description. -Cortical shell su bspherical,
nodose, pierced by a large number of small
pores. Two equatorial spines not in a line,
slightly directed downward. They are long,equal in length, gently tapered distally, sometimes slightly curved, and three-bladed. The
blades acute, much narrower than grooves,sometimes branched at the most proximal
part. Details of medullary shell uncertain.
Remarks.- The general shape of thisspecies is similar to that of P. tenuis (N akaseko and Nishimura, 1979) from which it isdistinguished by having equal polar spines.
It also differs from other species of the genus
by having much more acute ridges and moreor less obliquely directed polar spines.
Dimensions (in ,um).-Based on 15 speci-1209

mens. Maximum diameter of cortical shell :110-150. Length of equatorial spine: up to220.
Occurrence.-KIN 42, 44, 45, 69 and 71 (Tcassemblage).
Family Polyentactiniidae Nazarov, 1975
Remarks.- Nazarov and Ormiston (1985)
tentatively assigned the type gen us
Polyentactinia Foreman, 1963, to the Cenozoic family Orosphaeridae Haeckel. In my
Early to Middle Triassic materials, however,none have comparable dimensions to orosphaerids. They attributed the absence oforosphaerids from the Mesozoic probably to
extracting procedures. As a matter of fact,
however, much more delicate skeletons andfragments are easily obtainable from theMesozoic strata even through HF treatment.
It is thus quite reasonable to separate Polyentactinia from the Orosphaeridae based on
their stratigraphic distributions.
Genus Archaeosemantis Dumitrica, 1978b
Type species.-A. pterostephanus Dumitrica, 1978b.

Archaeosemantis cristianensis Dumitrica
Figures 14-3,6

Archaeosemantis pterostephanus (part.) Dumitrica,
1978b, p. 52, pI. 5, figs. 7, 8.
Archaeosemantis cristianensis Dumitrica, 1982c, p.
423, pI. I, fig. 11, pI. 3, fig. 11, pI. 4, figs. 5, 7, II,
pI. 6, fig. 2, pI. 7, figs. 3, 12, 13.
Archaeosemantis (?) sp. -Matsuda and Isozaki, 1982,
pI. 3, figs. 31, 32.
Archaeosemantis venusta Sash ida, 1983, p. 171, pI. 36,
figs. 1-9. -Sashida, 1991, figs. 5-4-8.
Archaeosemantis sp. aff. A. venusta - Sashida, 1991,
fig. 5-9.
Archaeosemantis sp. -Sashida, 1991, figs. 5-1-3.

Description.- Two forms of morphologic
variation are described below.
Morphotype A.-Four basal spines and two
to four apical spines possessing circular crosssection and acute tips, extending from bothends of short MB. Basal spines, two at each12 10K azuhiro Sugiy ama

941.

Lower and Middle Triassic radiolarians from central Japan"-

basal spines

Morphotype A

1211

basal spines

Morphotype B

Figure 15. Schematic illustration of two morphotypes of Archaeosemantis cristianensis. Dotted basal
spine in the morphotype A is homologous with a lateral spine with the same dot pattern in the morphotype
B. Dotted apical spine in the morphotype A is homologous with another lateral spine in the morphotype B.

end of MB, are almost equal in length, divergent downward approximately 45" from thehorizontal. They bent inwardly within theinterval between their proximal third andhalf, and never fuse terminally. They havemore or less nodular surface. The nodules
developed especially near the bending portion, sometimes forming short conicalspinules, and usually disappearing on the
distal part of spines. Apical spines, one
longer and one shorter at each end of MB, aremuch shorter than basal ones. They are
divergent upward approximately 20 to 45"
from the horizontal. Two longer spines of
one individual are always situated at the sameside to a meridional plane passing throughMB, and so are two shorter ones, so that thewhole spicule construction is bilaterally
asymmetrical to the meridional plane. The
surface of apical spines usually bears faintnodules but varies from smooth to nodular.
Shorter apical spines sometimes wart-like orcompletely absent.
0Morphotype B.-Two equal basal spines,
one shorter apical spine and one longer apicalspine arise from one end of MB. Theirmorphological characters are quite identicalto the corresponding half of morphotype A.
From the other end of MB arise one basal
spine, two lateral spines, and one apicalspine. The basal spine situated in a meridional plane passing through MB, having thesame features to the other two extending fromthe opposite end of MB. The two lateralspines more or less nodulated, equal in length
to the longer apical spine arising from the
opposite end of MB, and gently curved downward. The apical spine short, conical, directed upward, sometimes missing.
Remarks.- The spicule constructions of
the two above-described morphotypes areschematically illustrated in Figure 15.
According to my observations, there are
numerous intermediate forms between themorphotypes A and B. The transition frommorphotype A to B is caused by the rotation~
Figure 14. 1. 2: Pseudostylosphaera sp. A. 1: ESN 146178, KIN 45. 2: ESN 146180, KIN 45. 3,
6: Archaeosemantis cristianensis Dumitrica. 3: ESN 146194, KIN 38, morpho type A. 6: ESN 146195,
KIN 49, morphotype B. 4-Sb: Parasepsagon leptaleus sp. nov. 4: ESN 146188, paratype, KIN 37,
oblique lateral view. Sa: ESN 146187, holotype, KIN 49, basal view. Sb: Oblique lateral view. CS and
MS in 4 and 5b mean cortical shell and medullary one, respectively. 7a-l0: Parentactinia nakatsugawaensis Sashida. 7a: ESN 146197, KIN 49, oblique lateral view. 7b: Apical view. 8: ESN 146291, KIN 49.
9: ESN 146200, KIN 38. 10: ESN 146292, KIN 49, octaradiate form. Scale bars: 5b= 20 11m; others=
50 11m.

K azuhiro Sugiyama

1212

of half of morphotype A, which is approximately 4Y around the axis of MB, and simultaneous shortening of one basal spine. On
the basis of the fact that continuous transition
is easily traceable in a population, I consider
them as phenotypic variations of one and thesame species of A. cristianensis.
Dimensions (in ,um).-Based on 79 specimens. Height of morphotype A; 100-220.
Width of morphotype A; 70-150. Height ofmorpho type B; 100-210. Width of morphotype B ;70-150.
Occurrence.-KIN 2-8, 10, 14-16, 20, 21,
29-40, 47-57, 82-85, 90, 92, 93, 95-100 and
106-111 (Pn assemblage) and KIN 58-61, 6468 (Hg assemblage).
Genus Parentactinia Dumitrica, 1978b
Type species.-P. pugnax Dumitrica,
1978b.

Parentactinia nakatsugawaensis Sashida
Figures 14-7a--10
Unnamed spumellaria - Matsuda and 1sozaki, 1982,
pI. 3, figs. 33-35.
Parentactinia nakatsugawaensis Sash ida, 1983, pI. 37,
figs. 1-9. - Yeh, 1990, p. 12, pI. 4, fig. 9. -Sashida,
1991, p. 687, figs. 5-15,16,6-1,3-6.
(?) Pactarentinia koikei Sashida, 1991, p. 691, figs. 62,8-12.

Description.-Spicule composed of two
apical and two basal spines extending fromeach end of MB. Viewed along MB, typicalconstruction of spicule shows tetraradiate
profile, but it is sometimes viewed as octaradiate since the groups of spines radiatingfrom the two ends of MB are more or lessrotated with respect to one another. The
four apical spines usually consisting of two
shorter and two longer ones. The formergroup is conical to rodlike and without verticils, whereas the latter is rodlike, sometimes
as long as basal spines, and inclined to haveone verticil of spinules as the length increases.
All basal spines rodlike, straight, and bearing
one verticil of three or four spinules whichmore or less curve inward. Because the two
shorter apical spines are situated at the sameside relative to a meridional plane passing
through MB, the whole form always exhibits
an asymmetrical profile to the meridional
plane. Shell loosely latticed, commonly
resulted from the amalgamation of the
spinules on the basal spines. Secondary
meshwork connecting the spinules also developed to a certain degree. This shell is excl usively supported by basal spines and always
incomplete in the apical portion. The
nature and development of the shell is, however, quite variable. Thus some specimens
are exclusively characterized by the development of short, conical and unbranchedspinules and completely lack a lattice shell.
On the contrary, shell sometimes shows moreor less solid aspect, and may be supported byboth all basal and longer apical spines.
Remarks.- Recently Sashida (1991) described one new species Pactarentinia koikei,
which is similar to P. nakatsugawaensis but
has a shell supported by both basal andapical spines. In accordance with my observation, P. nakatsugawaensis has quite wide
variation regarding the shell development,
thus I consider that they cannot be distinguished only by the development of the shell.
Further investigation is necessary with respect
to this point. It is very interesting that someindividuals, having two long apical spines
which are almost equal to basal spines, aresimilar to the species of the nassellarian genus
Tandarnia Dumitrica, 1982c, since the longer
spines seem to correspond to L and I, whereas
the shorter ones are homologous with D and
Ax. The variational rotation around theaxis of MB indicates the phylogenetic closeness of this species and Archaeosemantis
cristianensis.
Dimensions (in ,um).-Based on 38 specimens. Diameter of shell; 70-150. Lengthof apical spine; up to 140. Length of basal
spine; 40- 200.
Occurrence.-KIN 2-8, 11,13, 14, 19-21,
29-40, 47-57, 76, 82-85, 89-93, 95-100 and941.

Lower and Middle Triassic radiolarians from central Japan

106-111 (Pn assemblage), KIN 59, 64-66 and68 (Hg assemblage) and KIN 69, 71-73 (Tcassemblage).

Parentactinia okuchichibuensis (Sashida)
Figures 16-2a,2bArchaeothamnulus okuchichibuensis Sash ida, 1991, p.
687, figs. 5-10-14.

Remarks.-Sashida (1991) mentioned that
this species is characterized by having pointcentered spines, four basal and one apical.
However, most specimens from Mt. Kinkazan
exhibit bar-centered profile with four basal
and one or two apical spines. Judging fromthe fact and its general shape, this species isclosely related to P. inerme Dumitrica, 1978b.
Occurrence .-KIN 30, 34-38, 40, 48-50,
52, 54, 97 and 108 (Pn assemblage).
Parentactinia ramosa (Sashida)
Figures 16-1
Archaeothamnulus ramosus Sashida, 1983, pI. 37,
figs. 10-12.

Remarks.- This species always exhibits
bar-centered profile, and the morphologic
variation shows the development of archlike
structure connecting distal portions of basal
spines. Thus this species should be assigned
to Parentactinia rather than Archaeothamnulus Dumitrica, 1982c (= Triassothumnus
Kozur and Mostler, 1981).
Occurrence.-KIN 37, 38 and 56 (Pn assemblage).
Genus Polyentactinia Foreman, 1963
Type species.-P. craticulata Foreman,
1963.

Polyentactinia (?) biacus Sugiyama, sp. nov.
Figures 16-3-5b

Descrzption.-Shell single, spherical toslightly ellipsoidal, loosely latticed, comprising an internal spicule. Lattice bars circular1213

to oval in cross section, often bearing nodes at
the junctions. MB eccentrically situated in
the shell. Four rays radiating from each endof MB. Two of them, opposite relative toMB, are tied to spines which arranged either
almost in a line or at an obtuse angle.
Spines rodlike to conical, tapered, thicker
than corresponding rays. One spine, situatednearer to MB than the other, is commonly
shorter. The other six rays connected withlattice bars, and not extending outside theshell.
Remarks.- This species is similar to
Pseudostylosphaera kozuri sp. nov. but differsfrom it in lacking a medullary shell. The
development of lattice shell is variable, andthe direction of the spines is also unstable.
Dimensions (in ,um).-Based on 29 specimens. Diameter of shell; 70-120. Lengthof longer spine; 40-100. Length of shorter
spine; up to 40.
Holotype .-ESN 146204 (Figure 16-4)
from KIN 50.
Occurrence.-KIN 31, 35-37,47-52 and 54(Pn assemblage).

Polyentactinia (?) crux Sugiyama, sp. nov.
Figures 16-6a-7b

Description.-Shell single, nearly spherical,
loosely latticed, comprising an internal
spicule, with four spines situated in theequatorial plane. Lattice bars circular tooval in cross section. Small nodes present at
the junctions of the lattice bars. MB is
eccentrically situated in the shell, each end ofwhich has two apical and two basal rays.
The former rays much shorter than the latter,
tied to the lattice bars, whereas the latter ones
extend into spines which are conical to rodlike, variable in length, and much thicker
than corresponding rays.
Remarks.- This species resembles Parasepsagon leptaleus sp. nov. but differs from it inlacking a medullary shell. It is distinguishedfrom P. (?) biacus sp. nov. by having fourspines rather than two.

1214

K azuhiro Sugiyama

941.

Lower and Middle Triassic radiolarians from central Japan

Dimensions (in ,um).-Based on 17 specimens. Maximum diameter of shell; 70-120.
Length of spine; up to 90.
Holotype.-ESN 146207 (Figures 16-6a,6b) from KIN 49.
Occurrence.-KIN 30, 35-37,40,49-51 and
53 (Pn assemblage).
Polyentactinia (?) spp.
Figures 17-1,2

Remarks.-In the Pn assemblage there are
numerous species provisionally assignable to
Polyentactinia but none are identified at the
specific level in this study.
Incerta Family
Genus Pentabelus Sugiyama, gen. nov.
Etymology.-From the Greek penta, five,and belos, dart, masculine gender.
Type species.-P. furutanii Sugiyama, sp.
nov. (by monotypy).
Diagnosis.- Internal spicule composed of
MB, A, D, two L, two I and Ax. V missing.
Five spines corresponding to the prolongations of A, two L and two I. D and Ax
short, connected with spherical shell, sometimes absent.
Remarks.- Nassellarian descri pti ve
terminology is conventionally used for thisgenus as for the eptingiid genera. It is, however, distinguished from the latter by lacking
V and having spines extending from the two I.
Detailed character of the shell is not established at this time. The family assignment is
uncertain.

Pentabelus furutanii Sugiyama, sp. nov.
Figures 17-3, 5a, 5b

1215

Description.-Shell pnmltlve, spherical,
formed of two AI, two Ll and LL and coarse,
thinner secondary lattice work connectingarch structure. Frontal side of internal
spiCUle also contributes to form a part of theshell. Lattice bars delicate, circular to ellipsoidal in cross section, bearing small nodes at
the junctions. A prolonged into a long,
rodlike spine. Two L and two I weakly bent
frontally at the verticil of arches, and prolonged into four acute spines of which theones arising from the two I are much shorter.
All spines thicker than corresponding rays,
tapered distally to a point, circular in crosssection. D, V and Ax as with genus.
Remarks.- The occurrence of this species
is rare in the Pn assemblage.
Dimensions (in ,um).-Based on 15 specimens. Diameter of shell; 70-115. Lengthof spine arising from A: 65-120. Length ofspine arising from L: 20-65. Length ofspine arising from I; up to 40.
Holotype.-ESN 146209 (Figures 17-5a,5b) from KIN 37.
Occurrence.-KIN 37, 40, 47 and 51 (Pnassemblage ).
Etymology.- This species is named after
Dr. Hiroshi Furutani of Hyogo Prefectural
Board of Education in honor of his great
contribution to the study of Paleozoic
radiolarians.
Order Spumellaria
Family Actinommidae Haeckel, 1862, emend.
Riedel, 1967bGenus Cenosphaera Ehrenberg, 1854
Type species.-C. plutonis Ehrenberg, 1854.

Cenosphaera andoi Sugiyama, sp. nov.

+-- Figure 16. 1: Parentactinia ramosa (Sashida), ESN 146185, KIN 37. 2a, 2b: Parentactinia okuchichibuensis (Sashida), ESN 146186, KIN 50. 3-Sb: Polyentactinia (?) biacus sp. nov. 3: ESN 146206,
paratype, KIN 49. 4: ESN 146204, holotype, KIN 50. Sa: ESN 146205, paratype, KIN 49. 5b:
Enlargement of MB. 6a-7b: Polyentactinia (?) crux sp. nov. 6a: ESN 146207, holotype, KIN 49, basal
view. 6b: oblique lateral view. 7a: ESN 146208, paratype, KIN 50, oblique basal view. 7b: Lateralview.

121 6

Kazuhiro Sugiy ama

941.

Lower and Middle Triassic radiolarians from central Japan

Figures 17-4,6

Description.-Single shell remarkably
porous, with more or less rugged surface.
Pores variable in shape, circular to irregular.
Pore frame variable in width, incomplete inmany parts, and often bearing small nodes.
Remarks.- This species is easily distinguished from C. clathrata Parona, 1890, by
its incomplete lattice work.
Dimension (in pm).-Based on 55 specimens. Diameter of shell; 60-250.
Holotype .-ESN 146215 (Figure 17-4)
from KIN 51.
Occurrence.-KIN 29, 31, 35-38,40,47 and
49-52 (Pn assemblage).
Etymology.- This species is named inhonor of Mr. Hideyuki Ando who first studied the geology of Mt. Kinkazan.
Family Oertiispongidae Kozur and Mostier,1980, emend. Kozur and Mostler 1981
Genus Oertlispongus Dumitrica, Kozur
and Mostler, 1980
Type species.-O. inaequispinosus Dumitrica, Kozur and Mostler, 1980.

Oertlispongus diacanthus Sugiyama, sp. nov.
Figures 17-10--12

Oertlispongus sp. - Bragin, 1991, pI. I, fig. 19.

Description.-Shell spongy, fragile, relatively small, spherical to subspherical, composed of numerous concentric layers, andbearing two polar spines and no conspicuousminor ones. The innermost structure of shellis unknown. Polar spines long, straight orslightly curved in the distal portion, tapered
distally, always circular in cross section;

1217

proximal part inserted in the shell and abruptly tapered to form a short cone on which
numerous thin thorns regularly arranged intransverse rows are observable when the shellis partly dissolved.
Remarks.- The occurrence of a completely
preserved individual, retaining a spongy shell,is very rare. The well-preserved part of theskeleton is usually restricted to the polar
spines as is the case with other oertlispongids.
Completely preserved individuals are easily
distinguished from other oertiispongids by its
two nearly straight polar spines. Such a feature of the polar spines is not applicable toany of previously designated oertlispongid
genera. In this study, therefore, the original
diagnosis of Oertlispongus is used in an enlarged meaning.
Dimensions (in pm).-Based on 51 specimens. Diameter of shell; 70-135. Lengthof polar spine; 160-330.
Holotype.-ESN 146229 (Figure 17-10)
from KIN 45.
Occurrence.-KIN 42-45 and 96 (Tc assemblage).
Genus Pegoxystris Sugiyama, gen. nov.
Etymology.-From the Greek pegos, solid,
and xystris, scraper, feminine gender.
Including species.-P. mizutanii Sugiyama
sp. nov. (type species) and an indeterminablespecies P. sp. A.
Diagnosis.-Shell composed of about fiveconcentric layers connected with one anotherby numerous beams radiating from the innermost layer in all directions. The shell surface bears relatively short, delicate minor
spines which are prolongations of the beams
and variable in length and shape of the crosssection. Two polar spines stout, long, usu-

~ Figure 17. 1,2: Polyentactinia (?) spp.
1: ESN 146293, KIN 49. 2: ESN 146203, KIN 47. 3, Sa,
5b: Pentabelus Jurutanii gen. et sp. nov. 3: ESN 146210, paratype, KIN 37. Sa: ESN 146209, holotype,
KIN 37. 5b: Apical view. 4,6: Cenosphaera andoi sp. nov. 4: ESN 146215, holotype, KIN 51. 6:
ESN 146214, paratype, KIN 37. 7: Pegoxystris sp. A., ESN 146219, KIN 49. 8, 9: Pegoxystris mizutanii
gen. et sp. nov. 8 ESN146221, holotype, KIN 37. 9: ESN 146223, paratype, KIN 50. 10-12: Oertlispongus diacanthus sp. nov. 10: ESN 146229, holotype, KIN 45. 11: ESN 146294, paratype, KIN 45. 12:
ESN 146295, paratype, KIN 45. All scale bars=50 Jim.

Kazuhiro Sugiyama

1218

ally unequal in length, extending from thecenter of shell, sometimes deviated from thepolar axis; proximal part increasing in thickness from the innermost layer to outside of
the shell, with polygonal cross section, sometimes slightly bladed; middle to distal partcircular in cross section, distally tapering.
With or without other spines extending fromthe equatorial portion of shell.
Remarks.- This genus differs from otheroertlispongid genera in having numerous
minor spines which are prolongations ofbeams and fewer concentric layers. The concentric structure of this genus also resembles
that of Paleozoic genera Copicyntra Nazarov
and Ormiston, 1985, and Provisocyntra N azarov and Ormiston, 1987. This genus is, however, distinguished from them by having two
characteristic polar spines.

Pegoxystris mizutanii Sugiyama, sp. nov.
Figures 17-8,9Description.- Test as with genus, without
equatorial spines. Minor spines densely distributed around the equatorial portion ofshell. They are circular to polygonal, sometimes bladed in cross section. Two polar
spines commonly in a line, sometimes at an
obtuse angle.
Remarks.- This species is characteristic for
the Pn assemblage.
Dimensions (in ,um).-Based on 25 specimens. Diameter of shell; 60-100. Lengthof longer polar spine; 70-200. Length ofshorter polar spine; up to 130.
Holotype.-ESN 146221 (Figure 17-8)
from KIN 37.
Occurrence.-KIN 29-31, 33, 35-40, 49, 51,
52, 56 and 109 (Pn assemblage).
Etymology.- This species is named after
Prof. Shinjiro Mizutani of Nagoya University
in honor of his great contribution to thegeology of the Mino terrane and Mesozoic
radiolarians.
Pegoxystris sp. A

Figures 17-7

Remarks.- This species is distinguishedfrom P. mizutanii by having a few or several
eq uatorial spines.
Occurrence.-KIN 29, 35-37,40,49 and 52(Pn assemblage).
Incerta Family
Genus Plafkerium Pessagno, 1979
Type species.-P. abbotti Pessagno, 1979.

Plafkerium (?) antiquum Sugiyama, sp. nov.
Figures 18-4-6

Slallrosphaera (?) sp. 8- Y ao el al., 1980, pI. 1, fig. 6.
(?) Slallrosphaera (?) sp. A- Yao el al., 1980, pI. 1,
fig. 5.
Slallrodoras (?) sp. -Mizutani and Koike, 1982, pI. 4,
figs. 1, 2.
(?) Slallrodoras (?) sp. -Sato el al., 1986, pI. 1, fig. 3.

Description.-Cortical shell subspherical,
more or less compressed, thick, spongy, composed of reticulated framework, consisting atleast of two layers; inner layer with densely
arranged small, polygonal to circular pores;
outer layer with rather loose pore frames
which bear relatively large, irregularly shaped
pores and small nodes at their junctions.
Details of medullary shell not known. Fourcoplanar spines not twisted, commonly atright angles; distal part thin, needlelike;
middle part rodlike or three-bladed: proximal part three-bladed. One spine is often
longer than the others. The blades on spines
often reduced to thin, cylindrical bars which
may be branched at the most proximal part ofthe spines. One of the branches on a spine
often extends directly toward one from adjacent spine to form a marginal ridge. Four
marginal ridges surround the cortical shell in
one plane resulting in a square outline. The
other branches connected with the poreframes of the cortical shell.
Remarks.- This species is distinguishedfrom previously known species of the genus
by its simple, not twisted spines. It seems

941.

Lower and Middle Triassic radiolarian s from central Japan

12 19

Figure 18. 1- 3 : Tiborella agria sp. nov . 1 : ESN 146232, paratype, KIN 38 . 2 : ESN 14623 1,
ho lo type , KIN 40. 3 : ESN 146230, paraty pe, KIN 40. 4- 6 : Plafkerium (?) anriquum sp. nov. 4: ESN
146233, paratype, KIN 40. 5 : ESN 146296, para type, KIN 56. 6 : ESN 146234, holotype, KIN 61.

that two morphotypic va ri atio ns a re present :One is characterized by spin es bl aded o nl y in
the proximal part, whereas the oth er has
nearly complete bl aded spines. The former
type commonly occurs in the Pn assemb lage
and the latter type is ab und ant in the H g and
Tc assembl ages.
Dimensions (in ,um). - Based o n 19 speci mens. Di ameter of cortical shell in th e planeof spines ; 100- 160. Len gth of spine; 70190.

Hololype.-ES N

146234(Figure 18- 6)

from KIN 61.

Occurrence. - KIN 29, 35, 39, 40, 54 and 56(Pn asse mbl age) , KIN 59 - 62 a nd 64- 68 ( Hgassemb lage) a nd KIN 42, 44- 46,69 a nd 71 - 73
(Tc assemblage).
Gen us Tiborella Dumi tri ca,
Kozur a nd Mostler, 1980
Type species. - T. magnidentata Dumitrica , Koz ur and Mo stler, 1980.

Kazuhiro Sugiyama

1220

Tiborella agria Sugiyama, sp. nov.
Figures 18-1-3

Description.-Cortical shell subspherical,
more or less compressed, latticed, bearing
nodes at the junctions of lattice bars, andhaving circular to irregularly shaped pores.
Medullary shell is delicate and somewhat
spongy, but its detailed structure is uncertain
owing to the poor preservation. Four cylindrical rays located in a plane, along two
rectangular axes, connecting medullary shellwith cortical one, and extending into spines
which are equal in shape and not twisted.
The distal to middle part of spines generally
thin, rodlike to slightly bladed, while theproximal one always bears four prominent
blades of which two are in the equatorial
plane and the other two are in a perpendicular plane. The equatorial blades extending
into those on adjacent spines to form four
marginal ridges on the side of cortical shell.
The perpendicular blades extending to thelattice bars forming the cortical shell.
Remarks.- This species differs from T.
magnidentata in having rodlike spines rather
than twisted ones. It is also distinguishedfrom Cecrops floridus Nakaseko and Nishimura, 1979, by lacking twisted spines withblunt or club-shaped distal ends.
Dimensions (in ,um).-Based on 25 specimens. Diameter of cortical shell; 75-110.
Diameter of medullary shell; 20-40.
Length of spine; 30-85.
Holotype.-ESN 146231 (Figure 18-2)
from KIN 40.
Occurrence.-KIN 32, 37, 38, 40, 49 and 56(Pn assemblage).
Acknowledgments
I would like to express my deep gratitude toProf. Junji Itoigawa of Nagoya University,
Drs. Pauli an Dumitrica of Institute of Geology and Geophysics, Romania, and Brian K.
Holdsworth, University of Keele, England,
who critically reviewed the manuscript andgave me valuable comments and suggestions.
I wish to express my hearty thanks to Drs.
Tomowo Ozawa and Shinobu Mori of
Nagoya University for their encouragement
and valuable suggestions during the study. I
would like to thank Dr. Hiroshi Furutani of
Hyogo Prefectural Board of Education for his
valuable advice on radiolarian taxonomy andencouragements. I am indebted to Prof. Toshio Koike of Yokohama National U niversity and Dr. Kozo Watanabe of Kohnodai
High School of Ichikawa City for
identifications of conodonts and helpfuladvice. Thanks are also due to Mr. Yusei
Kuroyanagi of Nagoya University for hiskindly preparing the microphotographs ofthin sections and valuable advice on thesedimentology and petrology of siliceous
rocks.
References
Ando, H., 1987: On the Permian clastic rocks from
Mt. Kinkazan Area, Gifu City. Geol. Soc.
Japan, Abstracts with Programs, 94th Ann.
Meet., p.278. (in Japanese)- - , Tsukamoto, H. and Saito M., 1991: Permian
radiolarians in the Mt. Kinkazan area, Gifu City,
central Japan. Bull. Mizunami Fossil Mus., no.
18, p. 101-106, pI. 9. (in Japanese with English
abstract)
Arakawa, R., 1986: Upper Paleozoic and Mesozoic
strata in the southeastern part of the Ashio
Mountains. Bull. Tochigi Pref Mus., no. 3, p.
1-37. (in Japanese with English abstract)
Blome, C.D., 1983: Upper Triassic Capnuchosphaeridae and Capnodocinae (Radiolaria)
from east-central Oregon. Micropaleontology,
vol. 29, no. 1, p. 11-49, pis. 1-11.
- - , 1984: Upper Triassic Radiolaria and radiolarian zonation from western North America.
Bull. A mer. Paleont. vol. 85, no. 318, p. 1-88.
- - , Jones, D.L., Murchey, B.L. and Liniecki, M.,
1986: Geologic implications of radiolarianbearing Paleozoic and Mesozoic rocks from theBlue Mountains province, Eastern Oregon. In,
T.L. Vallier, T.L. and Brooks, H.C., Geologic
Implications of Paleozoic and Mesozoic
Paleontology and Biostratigraphy, Blue Mountains Province, Oregon and Idaho. U.S. Geol.,
Surv. Prof Paper 1435, p. 79-93, pis. 8.1-8.3.
- - , Moore, P.R., Simes, J.E. and Watters, W.A.,

941.

Lower and Middle Triassic radiolarians from central Japan

1987: Late Triassic Radiolaria from Phosphatic
Concretions in the Torlesse Terrane, Kapiti
Island, Wellington. New Zealand Ceol. Surv.
Record, no. 18, p. 103-109.
Cheng, Y-N., 1986: Taxonomic Studies on Upper
Paleozoic Radiolaria. Natn. Mus. Nat. Sci.,
Taiwan, Spec. Publ., no. I, 311 p.
- - , 1989: Upper Paleozoic and Lower Mesozoic
Radiolarian Assemblages from the Busuanga
Islands, North Palawan Block, Philippines.
Bul!. Natn. Mus. Nat. Sci., Taiwan, no. I, p. 129175.
Deflandre, M.G., 1963: Pylentonema, nouveau genre
de Radiolaire du Viseen: Sphaerellaire ou Nassellaire ? C. R. Acad. Sci., Paris, ser. D, vol.
257, p. 3981-3984.
De Wever, P., 1981 : Une nouvelle Sous-famille, lesPoulpinae, et quatre novel les especes de Saitoum
Radiolaires mesozoiques tethysiens. Ceobios,no. 14 (I), p. 5-15.
- - , Sanfilippo, A., Riedel, W.R. and Gruber, 8.,
1979: Triassic radiolarians from Greece, Sicily
and Turkey. Micropaleontology, vol. 25, no. I,
p. 75-110, pis 1-7.
Dumitrica, P., 1978a: Family Eptingiidae n. fam.,extinct Nassellaria (Radiolaria) with sagittal
ring. D. S. Inst. Ceo!. Ceojiz, vol. 64, p.27-38,
pis. 1-4.
- - , 1978b: Triassic Palaeoscenidiidae andEntactiniidae from the Vicentinian Alps (Italy)
and Eastern Carpathians (Romania). Ibid., vol.
64, p. 39-54, pis. 1-5.
- - , 1982a: Triassic Oertlisponginae (Radiolaria)
from Eastern Carpathians and Southern Alps.
Ibid., vol. 67, p. 57-74, pis. 1-12.
- - , 1982b: Foremanellinidae, a new family ofTriassic Radiolaria. Ibid., vol. 67, p. 75-82, pis.
1-3.
- - , 1982c: Middle Triassic spicular Radiolaria.
Rev. Espanola Micropaleont., vol. 14, p. 401-428.
- - , 1984: Systematics of sphaerellarian radiolarians. In, Petrushevskaya, M.G. and Stepanjants,
S.D., Morfologiya, Ecologiya i evolYlllsiya
radiolyarii. Materialy IV simpoziuma evropeiskikh radiolyaristov EURORAD-IV, p.91-102
Nauka, Leningrad. (in Russian)- - , 1991: Middle Triassic Tripedurnulidae, n. fam.
(Radiolaria) from the eastern Carpathians(Romania) and Vicentinian Alps (Italy). Rev.
Micropaleont., vol. 34, no. 4, p.261-278.
- - , Kozur, H. and Mostier, H.,: Contribution to
the radiolarian fauna of the Middle Triassic of
the Southern Alps. Palaont. Mill. Innsbruck,vol. 10, no. I, p. 1-46.
Ehrenberg, G., 1854: Mikrogeologie. Leipzig,
xxviii +374 pp.
Atrls, 31 p., 41 pis. Fortestzung (1856), 88 pp.

1221

Foreman, H.P., 1963: Upper Devonian Radiolaria
from the Huron member of the Ohio shale.
Micropaleontology, vol. 9, no. 3, p.267-304, pis
1-9.
Gorican, S. and Buser, S., 1988/1989: Middle Triassic radiolarians from Slovenia (Yugoslavia).
Ceoloqija, 31, 32, p. 133-197.
Haeckel, E., 1862: Die Radiolarien (Rhizopoda
Radiolaria). Eine Monographie. xiv+572 p.,
iv+35 pis. Reimer, Berlin.
Hertwig, R., 1879: Der Organismus der Radiolarien.
In, Fischer, G., p. I-IV, 1-149, pis. 1-10. Jena.
Imota, N., 1984: Late Paleozoic and Mesozoic cherts
in the Tamba Belt, Southwest Japan (Part I).
Bull. Kyoto Univ. Educ., sec. B, no. 65, p. 15-40.
Ishiga, H. 1986: Late Carboniferous and Permian
radiolarian biostratigraphy of southwest Japan.
Jour. Ceosci., Osaka City Univ., vol. 29, art. 3, p.
89-100.
- - , Kito, T. and Imoto, N., 1982a: Late Permian
radiolarian assemblages in the Tamba district
and an adjacent area, Southwest Japan. Earth
Sci. (Chikyu Kagaku), vol. 36, no. I, p. 10-22.
- - , - - and - - , 1982b: Middle Permian
radiolarian assemblages in the Tamba district
and an adjacent area, Southwest Japan. Ibid.,
no. 5, p. 272-281.
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. 135-151. (inJapanese with English abstract)
Kishida, Y. and Sugano, K., 1982: Radiolarian zonation of Triassic and Jurassic in outer side ofsouthwest Japan. Ibid., p.271-300. (inJapanese with English abstract)
Koike, T., 1981 : Biostratigraphy of Triassic
conodonts in Japan. Sci. Rep., YokohamaNatn. Univ., sec. II, no. 28, p. 25-42.
Kojima, S. and Mizutani, S., 1987: Triassic andJurassic Radiolaria from the Nadanhada Range,
northeast China. Trans. Proc. Palaeonl. Soc.
Japan, N.S., no. 148, p. 256-275.
Kozur, H., 1984: New radiolarian taxa from theTriassic and Jurassic. Ceol. Paliiont. Mill. Innsbruck, vol. 13 (2), p.49-88.
- - and Mostler, H, 1972: Beitdige zur Erforschungder mesozoischen Radiolarien. Teil I: Revision der Oberfamilie Coccodiscacea HAECKEL
1862 emend. und Beschreibung ihrer triassischen
Vertreter. Ibid., vol. 2 (8/9), p. 1-60.
- - and, 1978: Ibid.. Teil II: Oberfamilie Trematodiscacea HAECKEL 1862 emend. und Beschreibung ihrer triassischen Vertreter. Ibid.,
vol. 8, p. 123-182.
- - and - - , 1979: Ibid.. Teil III: Die Ober-1222

Kazuhiro Sugiyama

familien Actinomacea HAECKEL 1862 emend.,
Artiscacea HAECKEL 1882, Multiarcusellacea
nov. der Spumellaria und triassische Nassellaria.
Ibid., vol. 9, p. 1-132.
- - and - - , 1981 : Ibid.. Teil VI: Thalassosphaeracea HAECKEL, 1862, Hexastylacea
HAECKEL, 1882 emend. PETRUSEVSKAJA,
1979, Sponguracea HAECKEL, 1862 emend.
und weitere triassische Lithocyc1iacea,
Trematodiscacea, Actinommacea und N assellaria. Ibid., Sonderbd., p. 1-208.
- - and--, 1982: Entactinaria subordo. nov., a
new radiolarian suborder. Ibid., vol. 11/12, p.
399-414.
- - and - - , 1989: Radiolarien und Schwammskeleren aus dem Unterperm des Vorurals. Ibid.,
sonderbd. 2, p. 147- 275.
Lahm, B., 1984: Spumellarienfaunen (Radiolaria)
aus den mitteltriassischen BuchensteinerSchichten von Recoaro (Norditalien) und denobertriassischen Reifingerkalken von
GroBrei ft i n g (Osterreich )-Systema ti k-Stratigraphie-. Miinchner Geowiss. Abh.,(A), I, 161 pp.
Matsuda, T. and Isozaki, Y., 1982: Radiolarians
around the Triassic-Jurassic boundary from thebedded chert in the Kamiaso area, Southwest
Japan. Appendix: "Anisian" radiolarians.
News of Osaka Micropaleont., Spec. Vol., no. 5,
p. 93-101. (in Japanese with English abstract)
Mizutani, S., 1990: Mino Terrane. In, Ichikawa, K.
et al., Pre-Cretaceous Terranes of Japan, publication of IGCP Project No. 224, p. 121-135.
- - and Koike, T., 1982: Radiolarians in the Jurassic 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. (in Japanese withEnglish abstract)
Nakaseko, K. and Nishimura, A., 1979: Upper
Triassic Radiolaria from Southwest Japan. Sci.
. Rep., Coli. Educ. Osaka Univ., vol 28, no. 2, p.
61-109.
Nazarov, B.B., 1975: Lower and Middle Paleozoic
Radiolaria of Kazakhstan. Akad. Nauk SSSR,
Orden a Trudovogo Krasnogo Znameni Geol.
Inst., Trudy, vol. 275, p. 1-202, pis. 1-21. (inRussian)- - and Ormiston, A.R., 1985: Radiolaria from theLate Paleozoic of the southern Urals, USSR andWest Texas, USA. Micropaleontology, vol. 31,
no. I, p. I-54, pis. 1-6.
- - and - - , 1987: A new Carboniferous radiolarian genus and' its relation to the multishelledentactiniids. Ibid., vol. 33, no. 1, p.66-73, pis.
1,2.
Nishizono, Y., Ohishi, A., Sato, T. and Murata, M.,

1982: Radiolarian fauna from the Paleozoic andMesozoic formations, distributed along the midstream of Kuma River, Kyushu, Japan. Newsof Osaka Micropaleont., Spec. Vol., no. 5,311326. (in Japanese with English abstract)
Otsuka, T., 1988: Paleozoic-Mesozoic sedimentarycomplex in the eastern Mino Terrane, Central
Japan and its Jurassic tectonism. Jour. Geosci.,
Osaka City Univ., vol. 31, art. 4, p. 63-122.
Parona, D.F., 1890: Radiolarie nei noduli se1ciosidel ca1care giurese di Cittiglio presso Laveno.
Soc. Geol. Italiana, Boll., vol. 9 (1), p. 1-46, pis.
1-6.
Pessagno, E.A., Jr., Finch, W. and Abbott, P.M.,
1979: Upper Triassic Radiolaria from the San
Hipolito Formation, Baja Carifornia. Micropaleontology., vol. 25, no. 2, p. 160-197, pis. 1-9.
- - and Blome, C.D., 1980: Upper Triassic andJurassic Pantanellinae from California, Oregon
and British Columbia. Ibid., vol. 26, no. 3, p.
225-273, pis. I-II.
Petrushevskaya, M.G., 1971: On the natural system
of Polycystine Radiolaria (Class Sarcodina).
In, Farinacci, A., ed., Proceedings II Planktonic
Conference, Rome, 1970, p.981-992. Tecnoscienza, Rome.
Riedel, W.R., 1967a: Some new families of Radiolaria. Proc. Geol. Soc. London, no. 1640, p. 148149.
- - , 1967b: Protozoa (Subclass Radiolaria). In,
Harland, W.B. et al., The Fossil Record, p. 291298. Geol. Soc. London.
Sashida, K., 1983: Lower Triassic Radiolaria fromthe Kanto Mountains, Central Japan. Part I :Palaeoscenidiidae. Trans. Proc. Palaeont. Soc.
Japan, N.S., no. 131, p. 168-178, pIs. 36,37.
- - , 1991: Early Triassic radiolarians from the
Ogamata Formation, Kanto Mountains, central
Japan. Part 2. Ibid, no. 161, p.681-696.
Sato, T., Murata, M. and Yoshida, H., 1986: Triassic
to Jurassic radiolarian biostratigraphy in thesouthern part of Chichibu terrane of Kyushu,
Japan. News of Osaka Micropaleont., Spec.
Vol., no. 7, p.9-23. (in Japanese with English
abstract)
Sugiyama, K., 1990: Early to Middle Triassic
radiolarian assemblages from Mt. Kinkazan,
Gifu City. Geol. Soc. Japan, Abstracts with
Programs, 97th Ann. Meet., p. 312. (in Japanese)- - , 1991a: Permian radiolarians from the Triassic
distributed in Mt. Kinkazan, Gifu City. Geol.
Soc. Japan, Abstracts with Programs, 98th Ann.
Meet., p. 148. (in Japanese)- - , 1991 b: Early to Middle Triassic radiolarians
from Mt. Kinkazan, Gifu Prefecture, central
Japan. Internal. Assoc. Radiolarian
Paleontologists, 6th Meet., Firenze, Abstracts, p.

941.

Lower and Middle Triassic radiolarians from central Japan77.

- - , Nobuhara, T. and Inoue, K., in press: Preliminary report on Pliocene radiolarians from theNobori Formation, Tonohama Group, Shikoku,
Southwest Japan. Jour. Earth Sci., Nagoya
Univ., vol. 39.
Takashima, K and Koike, T., 1982: Triassic radiolarian faunas in chert from some areas in Japan.
Ibid., Spec. Vol., no. 5, p.45-50. (in Japanese)
Takemura, A., 1986: Classification of Jurassic nassellarians. Palaeontographica, Abt. A, vol. 195,
p.29-74.
Wakita, K., 1988: Origin of chaotically mixed rockbodies in the Early Jurassic to Early Cretaceous
sedimentary complex of the Mino terrane, central
Japan. Bull. Geol. Surv. Japan, vol. 39, no. II,

1223

p.675-757.
Yao, A, 1982: Middle Triassic to Early Jurassic
Radiolarians from the Inuyama area, central
Japan. Jour. Geosci., Osaka City Univ., vol. 25,
art. 4, p. 53-70.
- - , Matsuda, T. and Isozaki, Y., 1980: Triassic
and Jurassic· Radiolarians from the Inuyama
area, central Japan. Ibid., vol. 23, art. 4, p. 135154.
Yeh, K., 1989: Studies of Radiolaria from the Fields
Creek Formation, east-central Oregon, U.S.A ..
Bull. Natn. Mus. Nat. Sci., Taiwan, no. I, p.43109.

- - , 1990: Taxonomic studies of Triassic Radiolaria from Busuanga Island, Philippines. Ibid., no.
2, p. 1-63.

Iwato !fipi. Gifu Ji&:.$., Mt. Kinkazan ~*W.
Ji&:.$..~*w~Tfi-~fi3.*l~.~~aft~~E:Ji&:.$..Ji&:.$.m~*w~~.!fi~ ~ G .ht-.:aft~{r.E:z.tU;j L. 3 -:>~aft~ff~ Hijt~1j L t-.:o -t.h G ft (I) Par-ml

entactinia nakatsugawaensis ff~ (Spathian), (2) Hozmadia gifuensis sp. nov. ff~ (early
Anisian), (3) Triassocampe coronata ff~ (middle Anisian) -C-;!; ~ 0 :IDl:ft~ {r.E:z. Jjh ,t-.:1liff\:~XEt.e G m;:::I~Uilt~Et9fj{~iJ' G, WilJ~:i1B~~fJJ1:.Et9t.e~FfftttXEEt9-C-ft;!; ~ iJ;. T1ft
iJ' GJllRt;::Tfi3.*~ (1) !(lfdsJ':{!fi. (2) ~.J':{!fi-?'-.,. - r, 1iZ.Lf~fi3.*~ (3).~:ti\?'-.,. - r cfl5f;~.hko itOti::i1B~iJ'G~G.ht-.:=.*c.:IDl:ft~{r.Et;::-:>\,'-C. -t~.:ti\:z.~ l: t-.:o ~ G.hk:lDl:ft~{r.E ~ ? t>. 4 ~~ 26 ~:fi:z.o3"tr«;~Et9t.e ~ ~ t;:: -:>\, ,-c~1(;:z.
:to.: t.e ~ t-.:ot~W;fI:J~Trans. Proc. Palaeont. Soc. Japan, N.S., No. 167, pp. 1224-1246, 9 Figs., September 30, 1992

942. TROPICAL MOLLUSCAN ASSOCIATION IN THE MIDDLEMIOCENE MARGINAL SEA OF THE JAPANESE ISLASDS:
AN EXAMPLE OF MOLLUSCS FROM THE OYAMA FORMATION,
TSURUOKA CITY, NORTHEAST HONSHU, JAPAN*
KENSHIRO OGASA W ARA
Institute of Geoscience, the University of Tsukuba,
Tennodai, Tsukuba 305
and

KAZUO NAGASAWA
Yamagata Prefectural Museum, Yamagata 990

Abstract. The early Middle Miocene molluscs of the Oyama Formation, Yamagata
Prefecture, Northeast Honshu, Japan, are considered to have occupied a marginal part of thetropical sea in northern Japan on the basis of biogeographic distribution of molluscan
associations including Geloina, Vicarya and Leporimetis. The molluscan fauna ischaracterized by the occurrence of Arcid-Potamid Fauna and abundant occurrence ofTellinidae (Macoma. Psammacoma. Tellina. Nitidotellina and Leporimetis) that are deepburrow detritus feeders. These peculiar occurrences in the Arcid-Potamid Fauna suggestthat there were well developed unconsolidated sandy mud bottoms in tidal flats of embayments where each species of the Arcid-Potamid Fauna and tellinid species had beenflourished. From a paleozoogeographical point of view, significant difference in faunal
association among correlatives with the Oyama Formation can be recognized between thoseof the areas of modern northwestern Yamagata Prefecture and southern Akita Prefecture, andalso between the Kadono area of Joban Coalfield and northward. This difference suggeststhat there were boundaries of tropical/subtropical marine conditions between these areas in
the early Middle Miocene. Leporimetis takaii from the Oyama Formation together withother occurrences in Japan are also discussed and described systematically.
Key words. Tropical, Neogene, Miocene, paleozoogeography, Oyama Formation,
Yamagata Prefecture(1986). Neogene molluscan studies of theJapanese Islands in the last three decades
allow us to consider their paleontologicaland geological significance from the viewpoints of paleoecology, paleozoogeography
and paleoclimatology.
In reference to such increased knowledge,
the molluscan association of the Oyama Formation was considered to be the most northern occurrence of tropical water molluscs ofthe early Middle Miocene in the Japanese

Introduction
Since Ogasawara and Tanai (1952) reported 19 molluscan species of 13 genera from the
Miocene Oyama Formation in Yamagata
Prefecture, a few additional paleontologicaland geological studies on the Oyama Formation have been done by Nishida and Chihara(1966), Tsuchiya et al. (1984) and Sato et al.
'Received June 8, 1992; accepted July 10, 1992
1224

942.

Tropical molluscs in the mid-Miocene marginal sea

Islands, mainly based on the geographicaldistribution of species/genera along theJapanese Islands (Chinzei, 1978, 1986;
Ogasawara, 1988). From the zoogeographical and paleoclimatological viewpoints,
the genera Geloina, Telescopium, Terebralia,
Ellobium and Globularia are keys to inferring
tropical-water conditions within the YatsuoKadonosawa (or Kadonosawa) faunal province in central to northern Japan (Chinzei,
1986; Tsuda et al., 1986).
The Geloina- Vicarya association of the
Oyama Formation was first reported by
Tsuda (1965) and Nishida and Chihara(1966) although they did not describe or
ill ustrate species.
In addition to this molluscan associationfrom the Oyama Formation of Yamagata
Prefecture, Hatai (1956) reported Globularia(?) monstrosa Hatai, which is synonymouswith G. nakamurai, from the Miocene
Takinosawa Formation in Okura-mura,
Mogami-gun, Yamagata Prefecture, which is
not so far from the locality of the Oyama
Formation. Although the Globulariabearing formation and its locality are not wellfollowed by any studies, the genus Globularia
is a representative of the tropical mangroveswamp fauna (Kobayashi and Horikoshi,
1958; Itoigawa et al., 1981; Taguchi, 1981 ;Majima, 1989).
On the other hand, typical molluscan associations of the so-called Arcid-Potamid
Fauna (Tsuda, 1965; Noda, 1973) which ischaracterized by such genera and species as
Vicarya, Vicaryella, Tateiwaia, Anadara
kakehataensis, A. makiyamai, Striarca uetsukiensis and so on, have been found fromvarious localities beyond the northern area of
Yamagata Prefecture (Noda, 1973; Chinzei,1986). Some of the most northern localities
yielded Vicaryella, one Potamidid mollusc is
V. teshimae Kanno and Ogawa from theTakinoue Formation in the Yubari district of
central Hokkaido (Kanno and Ogawa, 1964)
and the Furanui Formation, western part of
the Hidaka Mountains (Uchimura, 1991).

1225

However, fossil localities in the more northern parts of the Oyama Formation recorded
no Geloina species and also no tropicalmolluscan genera such as Terebralia, Globularia, Telescopium and Ellobium.
Consequently, the geographic distributionof the characteristic genera and species of the
Yatsuo-Kadonosawa Fauna in Japan suggeststhat the present locality of Yamagata Prefecture corresponds to the Middle Miocene tropical front area from a paleozoogeographicalviewpoint.
In the present paper, we mainly deal withthe molluscs newly collected from the Oyama
Formation during a field survey in Tsuruoka
City in 1990. In addition to this collection,
we report here some molluscs stored in
Yamagata Prefectural Museum which werecollected from the Oyama Formation at
Shimoshimizu and Oyama Park in 1969 by
Mr. Tamiya and others.
All of the specimens in the present work aredeposited in Yamagata Prefectural Museumof Yamagata City.
Geological setting
The Tertiary strata developed in the southwestern area in Tsuruoka City, Yamagata
Prefecture are restricted to Lower to Middle
Miocene and it covers unconformably the
pre-Tertiary granitic rocks. It is divided into
the Irakawa, Zempoji, and Oyama Formations, in ascending order (Tsuchiya et al.,1984) (Figure 1).
The Irakawa Formation, which is thelowest stratigraphic unit of the Tertiary in thearea, is composed of felsic and andesitic
pyroclastics, andesitic lava flows, sandstoneand siltstone intercalated with conglomerateand carbonaceous layers. The Irakawa Formation is a terrestrial deposit and yielded theAniai-type Flora (Tan ai, 1951).
The Zempoji Formation unconformably
overlies the Irakawa Formation and is composed of conglomerate, andesitic lava, felsic

Kenshiro Ogasawara and Kazuo Nagasawa

1226

Figure 1.
1984)Stratigraphic division

Lithology & Fossils

Kusanagi Formation(100-400 m)

hard siltstone intercalated with sandstone andfelsic tuff

Oyama Formation(200-450 m)

felsic-andesitic tuff,
tuffaceous sandstone, mudstone andconglomerate
Mollusca, Foraminifera

Zempoji Formation(200-500)

felsic-andesitic tuff, tuffaceous
sandstone and mudstone
andesitic lava, conglomerate
Daijima-type Flora

Irakawa Formation(300 m+)conglomerate, sandstone and mudstone
with carbonaceous mudstone
andesitic lava, felsic pyroclastics
Aniai-type Flora
Unconformity
Pre-Tertiary Granitic rocks

Lower to Middle Miocene stratigraphic divisions of the studied area (after Tsuchiya et ai.,

and andesitic tuffaceous sandstone and mudstone. This formation yielded many plantfossils belonging to the Daijima-type Flora(Tanai, 1951; Sato et al., 1986). The
Zempoji Formation is intruded by the Shorenji Dolerite which is rather widely distributedin the southwestern part of Tsuruoka City.
This dolerite is considered to have been
intruded at the time of deposition of the
Oyama Formation (Tsuchiya et al., 1984).
The Oyama Formation is mainly composedof conglomerate, alternation of tuffaceous
sandstone and siltstone, massive siltstone,
felsic lapilli tuff and tuffaceous sandstone,
and alternating sandstone and siltstone. It
attains about 300 m in thickness. This formation yielded not only molluscs but also
silicified wood and many plant fossils.
Molluscs occurred as molds and casts. The
Oyama Formation is conformably overlain
by the Kusanagi Formation which is mainlycomposed of hard siliceous siltstone.
Occurrence of molluscs
Three molluscan fossil localities of the
Oyama Formation in the present report are

Sakashita, Shimoshimizu and Oyama Park
(Figure. 2). Among these, the Oyama Park
locality is the same as the locality of Tsuchiya
et al. (1984). However, the other localities
are different from the previously reported
ones by Ogasawara and Tanai (1952) andNishida and Chihara (1966). These fossil
localities are correlatable with the middle toupper part of the Oyama Formation.
All molluscs of the present report occurred
as inner and outer molds or casts but thedelicate surface sculpture is rather well preserved. Almost all the bivalve molluscs such as
Anadara kakehataensis, Diplodonta ferruginata, Cyc/adicama cf. takeyamai,
Cyclina japonica, Clementia papyracea, Leporimetis takaii and Hiatula minoensis occur
as conjoined valves. Such molluscan occurrences in the Oyama Formation suggest, ingeneral, that the molluscs are autochthonous.
The exposure at Sakashita is composed ofalternating tuffaceous sandstone and siltstone(16 m thick), mollusca-bearing massive graysiltstone (22 m thick), alternation of
tuffaceous sandstone and siltstone (10 mthick), Vicarya-Anadara-bearing tuffaceous
silty sandstone (14 m thick) and tuffaceous

942.

Tropical molluscs in the mid-Miocene marginal sea

1227

Figure 2. Fossil locality map (Adapted from Geographical Quadrangle Map "Sanze" and "Tsuruoka,"scale I : 50,000, Agency of Land and Survey, Ministry of Construction)

Kenshiro Ogasawara and Kazuo Nagasawa

1228

Tuffaceous siltstone (silicified wood)
Pumiceous tuff
Tuffaceous sandstone with molluscan
fossils..

A

Alternating beds of' pumice tuff, siltstone and tuffaceous sandstoneJ

Tuffaceous siltstone

Siltstone with molluscan fossils..

B

Alternating beds of sandy tuff, tuffaceous
sandstone and siltstone(silicified wood)

10

5

Figure 3.

Geologic column at Sakashita showing the fossil-bearing horizons of the Oyama Formationsiltstone intercalated with fine tuff (4 mthick), in ascending order (Figure 3). Thissection is correlated to the middle to upper
part of the Oyama Formation. It is interesting that abundant conjoined valves of Cycladicama, Diplodonta and Leporimetis species
occurred from a siltstone of the lower part
(Horizon B), while abundant conjoined
valves of Anadara kakehataensis and Le-

porimetis takaii associated with Vicarya yokoyamai were collected from a silty sandstone of the upper part (Horizon A).
At Shimoshimizu, in a road cut on
National road Route No.7, weakly stratified
silty sandstone and mollusc-rich sandy siltstone about 10 m in total thickness are
exposed. Among the molluscs sporadicallyoccurring from the top of this cutting,942.

Tropical molluscs in the mid-Miocene marginal sea

bivalves are mostly conjoined. This locality
is the uppermost horizon of the present three
localities.
The third locality is a small cliff in thesoutheastern part of the Shimoike Pond in the
Oyama Park. Molluscs from this locality
were collected in 1969 by Tamiya et al. The
lithofacies of the locality is characterized byill-sorted silty sandstone irregularly containing granular conglomerate. In this locality,
conjoined bivalves of Anadara kakehataensis and Diplodonta Jerruginata aredominant in association with conjoined
bivalves of Leporimetis and Clementia. The
association is very similar to those of theother two localities in specific composition.

Molluscan associations
As shown in Table I, 30 moll uscan species
from the three localities in the Oyama Formation have been identified. Among these,

Anadara kakehataensis, Diplodonta Jerruginata, Cycladicama cf. takeyamai,
Cyclina japonica, Leporimetis takaii and
Hiatula minoensis are dominant. It is interesting that Leporimetis takaii occurs in all of
the localities although the lithofacies andmoll uscan associations slightly differ in each.
Moreover, Leporimetis takaii and its associations are most characteristic in comparison
with other localities that have yielded theKadonosawa Fauna in Japan. The othermolluscan species, except for some tellinid
bivalves, are very similar to those of theArcid-Potamid Fauna of the Kadonosawa
faunal association (Chinzei and Iwasaki,
1967; Chinzei, 1981, 1986; Itoigawa et al.,
1981, 1982; Taguchi, 1986).
Unfortunately, a few genera such as
Geloina, Striarca and tellinids that were previously reported from the Oyama Formation(Ogasawara and Tanai, 1952; Nishida andChihara, 1966) were not collected in thepresent study. However, the most characteristic species are included in the present collections. Moreover, it can be said that the1229

molluscan associations of each locality arevery similar to each other.
Consequently, a total of 30 genera and 40
species are identified from the Oyama Formation including the species reported previously. Among these, Leporimetis takaii (including L. nipponica (Oyama MS) as a synonym),

Nitidotellina kagayamaensis, Cultellus otukai
and C. oyamaensis were previously describedfrom the Oyama Formation by Ogasawara
and Tanai (1952).
Age and correlation

A nadara kakehataensis, Leporimetis takaii, Hiatula minoensis, Vicarya yokoyamai
and Cerithideopsilla yatsuoensis are verysignificant for age determination andpaleoenvironmental reconstruction of the
Oyama Formation.
Leporimetis takaii is considered to be apeculiar species within the Kadonosawa
Fauna. This species is known from theKurosedani Formation of Toyama Prefecture(Oyama, 1950), Yoshino Formation of Katsuta Group, Okayama Prefecture (Taguchi,1981), Sunakozaka Formation of IshikawaToyama Prefectures (Sasaki and Ogasawara,1986), Kunimi Formation of Fukui Prefecture (Nakagawa, 1989) and Tamagawa Formation of Ibaraki Prefecture (Noda et al.,1989).
Moll uscan associations containing Vicaryayokoyamai are very comparable with those of
the Kadonosawa Fauna of the early Middle
Miocene in Japan.
According to the biochronological compilation of Saito et al. (1986) and Oda (1986),
the Kadonosawa Fauna can be assigned anage range of 16.5 to 15 Ma, however the oldest
Neogene Vicarya species is known from the
Kunugidaira Formation of Joban coalfieldon Honshu Island (Kamada, 1962; Takahashi, 1984), is of Early Miocene age (19 Ma)(Ogasawara, 1988).
The Oyama Formation is also correlatable
to those of Globularia-bearing formation re-Kenshiro Ogasawara and Kazuo Nagasawa

1230
Table 1.

Molluscan fossils from the Oyama Formation, Yamagata Prefecture
Locality numbers

SpeciesIB

VA

Anadara (Hataiarca) kakehataensis Hatai and Nishiyama
Anadara sp.
Solamen cf. fornicatum (Yokoyama)
Crassostrea gravitesta (Yokoyama)"Ostrea" sp.
Diplodonta ferruginata Makiyama
Cyc/adicama cf. takeyamai (Otuka)
Cyc/adicama sp.
Vasticardium ogurai (Otuka)
Cardilia toyamaensis Tsuda
Cyclina japonica Kamada
Clementia papyracea (Gray)
Paphia cf. ohiroi Masuda
Leporimetis takaii (Ogasawara and Tanai)
Macoma aff. praetexta (v. Martens)
Macoma sp.
Tellina cf. notoensis Masuda
Tellina cf. osafunei Taguchi
Nitidotellina kagayamensis (Ogasawara and Tanai)
Psammacoma aff. awajiensis (Sowerby)
Hiatula minoensis (Yokoyama)
Cultellus izumoensis Yokoyama
Cultellus sp.
Teredo sp.
Vicarya yokoyamai Takeyama
Cerithideopsilla yatsuoensis Tsuda
Cerithidea sp.
Chicoreus cf. tiganouranus (Nomura)"Cirsotrempsis" sp.
"Natica" sp.

IA

2

3
F

VA

F
F

F
R

R

A

VA
VA
C
F
F
VA
C
F
A

F
C

F

C
A

C

A

C
F

F

C
F
R

F
VA

F
C

R

F
R

F

R

F
R

F

F

F

F
F

V A: more than 20 individuals, A: 19-10 individ., C: 9-5 individ., F: 4-2 individ., R: I individ.
Locs. IB, IA: Sakashita, Oyama·machi, Tsuruoka City. B. Lower horizon, A. Upper horizon.
Loc. 2: Shimoshimizu, Turuoka City
Loc. 3: Oyama Park, Oyama·machi, Tsuruoka City

ported by Hatai (1956) in terms of Miocene
climatic succession as it is assignable to tropical marine conditions.
The Oyama molluscan association is very
allied to those of the Kakehata and Dohassociation of the Kurosedani Formation(Hatai and Nisiyama, 1949: Oyama, 1950;
Tsuda, 1959, 1960), Ajiri and Shiogama Formations of Miyagi Prefecture (Nomura, 1935),
and also Kadonosawa Formation of Iwate
Prefecture (Otuka, 1934). It is also very similar to those of the Okushiri Formation (Tsuri-

942.

Tropical molluscs in the mid-Miocene marginal sea

kake Fauna; Uozumi and Fujie, 1966), Kunnui Formation (Kanno, Amano and Noda,
1988) and lower part of the Sugota Formation of Akita Prefecture (Ozawa et al., 1979;
Sasaki, 1991).

Paleoenvironment
The present molluscan collection from the
Oyama Formation is insufficient for a
detailed discussion of the depositional
paleoenvironments of the Oyama Formation,
but we focus on the zoogeographicalsignificance of the dominant molluscan
species and its association.
As compared with those of the Kadonosaw a Fauna, the most characteristic featuresof the Oyama Fauna is abundant cooccurrence with elements of the ArcidPotamid Fauna together with Leporimetis
takaii. Some modern specimens of Leporimetis spectabilis and its allied species are
known from tropical seas as far south as
Okinawa, where they live on fine sandy bottoms at littoral to very shallow water depths(Habe, 1977). By analogy, Leporimetis takaii can be considered a tropical species.
According to Taguchi (1981), who reconstructed the brackish interspecific associationof the Kadonosawa Fauna as exemplified by
the Bihoku Group in Southwestern Japan, theVicarya-Geloina Association included noLeporimetis species; however, he reported
Apolymetis sp. from the Bihoku Group.
However, Leporimetis species are known fromsome localities in the Japanese Islands
although not to the degree to which theyoccur in comparison with that of the Oyama
Formation. This difference probably resulted from bottom conditions, whether wellconsolidated or not, because Leporimetis is a
representative detritus feeder or deep burrower. Its peculiar external shape of ridgeand depression at central portion on shellsuggests some suitable adaptation formaintaining a life position in such unconsolidated muddy sand bottoms. In addition,

1231

occurrence of many tellinid species in association with Leporimetis takaii also suggeststhat soft muddy bottoms were well developed
at the time of deposition of the Oyama
Formation.
The Arcid-Potamid Fauna of the Kadonosawa Fauna is considered to have flourishedIII
brackish embaymental to lagoonalenvironments as many molluscan paleontologists have discussed (Tsuda, 1965;
Noda, 1973; Chinzei, 1978 and others).
Specific association of the Oyama Formationsuggests an environment similar to that cited
above, combined with rare occurrence ofCerithideoposilla yatsuoensis. Based on thepattern of conjoined occurrence of the specimens and species associations, the Oyama
Fauna suggests a principal environment inunconsolidated muddy bottoms in brackish
to open shallow seas. As Chinzei discussed,
Crassostrea may be specially adapted to live
in and on mud bottoms as they have chalkystructured shell (Chinzei, 1982a-b). On theother hand, Leporimetis may have adapted tolife in unconsolidated muddy bottoms by thedepressed portion of its shell surface. Undiscovered and/or very rare occurrence of Crassostrea from the Oyama Formation is explained by such environmental differences ascited above.
From a paleo-marine climatological pointof view, Geloina- Vicarya and associatedspecies indicate tropical-water conditions.
Geloina and other mangrove species such as
Globularia, Terebralia and Telescopium havenot been recorded in any strata north of thepresent Oyama Formation in the northwestern part of Yamagata Prefecture.
For instance, from the Dewa Hill area of
Akita Prefecture, the lower part of the Sugota
Formation yields Batillaria sp., Vicaryellanotoensis, A nadara sp. and Crassostrea
gravitesta (Sasaki, 1991) but Vicarya, Geloina
and Leporimetis have not been discovered.
Distorsio kotakai, one of the tropical tosubtropical species, was described from the
Yanagawa Formation, Fukushima PrefectureKenshiro Ogasawara and Kazuo Nagasawa

1232

together with many warm-water species, but it
was considered as subtropical based on molluscan associations (Ogasawara and Morita,
1990).
From the Tamagawa Formation in Ibaraki
Prefecture, a Vicarya-A nadara kakehataensis-bearing molluscan fauna was reported

.,
.2
·3 e4

0

Q

.22

_25 .

0

2~·24

.2.

o

.30

·31

·33
·3 •

• 35

37.-360

as- .39 0

·.0

."

o

.'2

·.3

o

o
.51

e

.50

e

rU1USKliU

o
o

o

·.2

'O'j~~

by Noda et al. (1989). However, Geloina
and other typical mangrove species were notdiscovered. However, Terebralia sp. whichis assignable to one of the representative
genera of the tropical mangrove swamp
fauna, was reported together with many constituent species of the Arcid-Potamid Fauna
from the Nakayama Formation distributed in
the Kadono district of Joban Coalfield by
Takahashi (1984). This Nakayama Faunaof the Joban Coalfield should be consideredas tropical following studies concerning themangrove swamp fauna (Taguchi, 1981;
Tsuda et al., 1986; Itoigawa and Tsuda,1986).
Therefore, it can be concluded that thetropical-sea front and/or tropical mangrove
front should be put at the following twoareas: the Oyama Formation in Yamagata
Prefecture and the Nakayama Formation in
the Kadono district, Fukushima Prefecture.
All localities which yielded the Kadonosawa
Fauna in northern Japan are shown in Figure
4. Among these, some localities have norecords of tropical mangrove species although
they occurred south of Tsuruoka in
Yamagata Prefecture and the Kadono districtof Fukushima Prefecture such as the Tamagawa Formation (No. 61; Noda et al., 1989)
and the Kozono Formation in Saitama Prefecture (No. 62; Majima and Takahashi,
1987; Majima, 1989). This should be interpreted at present as due to insufficient collection of molluscs or lack of exposures.

..,

Figure 4. Fossil localities to be correlated tothat of the Oyama Formation in northern Japan.
I. Takinoue, 2-4. Furanui, 5. Kunnui, 6-7. Tsurikake, 8. Ohanzai,9. Yoshioka, 10. Isomatsu & Fuyube,
II. Takahoko, 12. Benkeinai, 13-17. Tanosawa, 18.
Tanosawa (Takibuchi-damsite), 19-20. Sunakose,21.
Kuroishizawa, 22-24. Kadonosawa, 25. Oinosawa,
26. Hanawa, 27-29. Nishikurosawa, 30. Sunakobuchi, 31. Mikaeritoge, 32-34. Iioka, 35-40. Sugota,
41. Shunezaka, 42. Oyama, 43. Okura-mura, 44.
Shiogama & Ajiri, 45. Moniwa, 46. Hashimoto, 47.
Tsukinoki, 48-49. Zaoh, 50. Myozawabashi, 51.
Kamagui, 52. Kozai, 53. Yanagawa, 54-56. Orito,
57. Taira, 58-60. Nakayama (Kadono), 61. Tamagawa, 62. Kozono.

942.

Tropical molluscs in the mid-Miocene marginal sea

Paleogeography and shallow marine
zoogeographic divisions at the time theKadonosawa Fauna flourished (about 16 Ma)
are shown in Figure 5. This paleogeographic map is modified on the basis of Chiji
and IGCP-246 National Working Group ofJapan (1988) and Hayashida and Torii(1988), which was proposed from the viewpoint of paleomagnetic studies of southwestern Japan.
Concerning the geographic distribution of
one element of the Arcid-Potamid Fauna, it isnotable that the geographical distribution ofStriarca uetsukiensis extends farther norththan Chinzei considered (1986). Because thespecies is known from the Okushiri, Kunnui
and Kadonosawa Formations in northern
Japan, it is considered that Striarca uetsukiensis occurs both in tropical and subtropical seas.
Description of characteristic molluscan
species of the Oyama Formation
Phylum Mollusca
Class Bivalvia
Family Arcidae Lamarck, 1809
Genus Anadara Gray, 1847
Subgenus Hataiarca Noda, 1966
Anadara (Hataiarca) kakehataensis
Hatai and Nisiyama
Figures 7-18,-20a-c.

Anadara kakehataensis Hatai and Nisiyama, 1949, p.
88, pI. 23, figs. 8-10.
Anadara (Hataiarca) kakehataensis Hatai andNisiyama. Noda, 1966, p. 116, pI. 2, fig. 17, pI. 13,
figs. 7, 8, 10-15,21; Noda, 1973, pI. 18, figs. 116: Taguchi, 1981, pI. 2, figs. 1-5; Sasaki andOgasawara, 1986, pI. 5, figs. la-b, 4a-b; Noda
and Takahashi, 1986, pI. 5, figs. 1-11 ; Kanno,
Amano and Noda, 1988, p. 379-380, pI. 1, figs. 12; Nakagawa, 1989, pI. 1, fig. I.
A nadara (Hataiarca) cf. kakehataensis Hatai andNisiyama. Takahashi, 1984, pI. 1, fig. I.

Valve

LengthHeight

SS·I

lel\

47.40

35.01

ca.14.4

·2

right

42.60

34.01

ca. 8.4

28
28

·3

lert

47.40+

ca.38

ca.15.5

25+

-4

left

45.15

38.70

17.6

25+

·5

right

45.60

34.40

13.4

28

·6

lef\

ca.35

ca.28

·7

right

23.60

18.30

5.0

25+

·8

right

44.30

25+

deformedconjoined

conjoined

Remarks.- This species resembles Anadara daitokudoensis Makiyama, but isdiscriminated from the latter by a wellinflated and high shell with about 26 radialribs. The localities of Anadara kakehataensis were shown by Noda and Takahashi (1986).
This species is one of the representative
species of the Arcid-Potamid Fauna of Tsuda(1965), and is a brackish inner embaymental
tidal to very shallow water species as pointed
out by Noda and Takahashi (1986).
Geologic records.-Kunnui and Tsurikake
Formations in Hokkaido, Tanosawa andMaenokawa Formations of Aomori Prefecture, Kadonosawa Formation ofIwate Prefecture, Ajiri and Tsukinoki Formations of
Miyagi Prefecture, Meganebashi Formationof Yamagata Prefecture, Iwafune and Orito
Formations of Niigata Prefecture, Kurosedani and Sunakozaka Formations of Toyama
Prefecture, Higashiinnai, Sunakozaka andKawaminami Formations of Ishikawa Prefecture, Kunimi Formation of Fukui Prefecture,
Katsuta and Yoshino Formations of the
Bihoku Group of Chugoku district, Nakayama Formation of Fukushima Prefecture,
Asakawa and Tamagawa Formations of Ibaraki Prefecture, and Eoil Formation of
Korea.
Family Ungulinidae H. and A. Adams, 1857
Genus Diplodonta Bronn, 1831
Diplodonta ferruginata Makiyama
Figures 7-6a-c,-7a-c,-8.

Measurements (in mm)
Coil. no.

1233

Depth

No. of rib

Remarks

Diplodonta Jerruginata Makiyama, 1926, p. 157-158,
pI. 12, figs. 12, 13; Uozumi and Fujie, 1966, p.
150, pI. 12, figs. 8, 9: Itoigawa in Itoigawa et al.,

1234

Kenshiro Ogasawara and Kazuo Nagasawa

Paleogeography (ca. 16 Ma)

o
o
o
o
SF

warm water(tropical &subtropical)
cold water(cool-temperate)
land areas

Figure 5. Paleogeography and shallow marine zoogeographic divisions of the Kadonosawa Fauna at
about 16 Ma, showing the tropical front and/or mangrove swamp faunal front (TP) and subtropical front (SF).

942.

Tropical molluscs in the mid-Miocene marginal sea

1974, p. 76, pI. 19, figs. 5a-c; Itoigawa et al.,
1981-1982, p. 70, pI. 12, figs. 8a-b, 11 a-b; Nakagawa and Takeyama, 1985, pI. 17, fig. 1 ;Ozawa et al., 1986, pI. 14, fig. 10.
Taras ferruginata (Makiyama). Otuk a, 1934, p.616,
pI. 45, figs. 29, 40.
Felaniella ferruginata (Makiyama). Sasaki and Ogasawara, 1986, pI. 5, fig. 10; Nakagawa, 1989, p.
37, pI. 1, fig. 9.

Measurements (in mm)
Coil. no. Valve Length Height H/L Depth D/LRemarks

SK-I

right

21.70

20.00

0.92 10.4/2 0.24

not deformed

-2

right

22.60

18.50

0.82 12.0/2 0.27

weak. compressed

-3

right

19.40

20.60

1.06 10.4/2 0.27

deformed

·4

left

21.70

20.10

0.93

deformed

·5

left

24.00

21.40

0.89

6.0

0.25

-6

right

20.00

18.50

0.93

6.2

0.31

deformed

Remarks.-According to the originaldescription, the holotype was measured as
18.0 mm in length, 15.5 mm in height and 5.4
mm in depth. The form ratios of theholotype are 0.86 in Height/Length and 0.3 in
Depth/Length. Measurements of specimensfrom the Oyama Formation are shown above,and it is considered that the Oyama specimens
are an intraspecific variation of D. ferruginata, although they are more or lessdeformed. The species bears no lunule andno escutcheon with pointed beak.
As workers have differed on the genericplacement of this species, including it also in
Felaniella and Diplodonta, the presence of
escutcheon and external ligament are a good
key for identification. The Oyama specimens belong to Diplodonta mainly based on
the lack of escutcheon.
Genus Cycladicama Valenciennes, 1854
Cycladicama cf. takeyamai (Otuka)
Figures 7-1,-3; 9-8,-9.
Compared with; Joanisiella takeyamai
1938, p. 29, pI. 4, figs. 32-34, 37.

Measurements (in mm)

Otuka,

1235

Coil. no. Valve Length Height Depth H/L D/LRemarks

00-1

left

26.30

21.00

6.0

0.8

0.23

typical form

00-2

right

21.30

18.10

5.85

0.85 0.27

typical form

00-3

right

27.80

19.00

11.0

0.68 0.4

elongated

00-4

right

25.30

20.70

0.82

beak missed

00-5

right

16.70

15.20

8/2

00-6

right

25.55

18.50

13.2/2 0.72 0.26

elongated

00-7

left

24 .. 20

21.00

13.6/2 0.87 0.28

conjoined

00-8

left

24.40

19.10

0.78

depressed

0.91

0.24 conj. small type

Remarks.- The genus Joanisiella Dall,
1895 is considered to be preoccupied by
Cycladicama Valenciennes, 1884 as noted by
Habe (1977). According to original measurements, the Height/Length and Depth/
Length ratios vary from 0.79 to 0.96 and 0.28
to 0.4, respectively. The specimens from the
Oyama Formation are most allied to C. takeyamai but are large in size and less inflatedcompared with the type specimen.
Cycladicama meisensis (Makiyama) is very
close to the present species but the former
differs from the latter in having a well developed umbonal area.
Family Veneridae Rafinesque, 1815
Genus Clementia Gray, 1842
Clementia papyracea (Gray)
Figures 7-11a-b, -12,-13; 9-22, -30.

Clementia papyracea (Gray). Ogasawara and Tanai,
1952, p. 208, pI. 19, figs. 4, 5; Shuto, 1960, p. 140,
pI. 13, figs. 8, 11, text-figs. 5, 6, 9; Itoigawa in
Itoigawa, Shibata and Nishimoto, 1974, p. 93, pI.
27, figs. 6a-b.
Clementia japonica Masuda, 1955, p. 121, pi. 19, fig.
8; Masuda, 1966, pI. 35, fig. 30.

Measurements (in mm)
Loc. Shimoshimizu
Coil. no. Valve Length Height Depth H/L D/LRemarks

SS-I

right

ca.49.0 46.10 20.0/2 0.94 0.20

-2

right

44.10

43.00 24.0/2 0.98 0.27

-3

right

32.40

37.60

18.6/2 1.16 0.29

elongated

-4

right

34.2+

31.70

13.4/2-poster. miss.

-5

left

33.50

30.50

-6

right

28.00

20.30

9.0

not deformed

elongated

0.91

deformed

0.76 0.32

deformed

Kenshiro Ogasawara and Kazuo Nagasawa

1236

Remarks.- This species may have flourished on the muddy bottom of a shallow
warm-water sea. Clementia japonica described by Masuda from the Higashi-Innai
Formation is characterized by transversely
elongated shell (34 mm height, 44 mm lengthand 13 mm depth; H/L=O.77; D/L=0.30),
but it is considered to be an intraspecificvariation of the present species. The specimens from the Oyama Formation can not be
discriminated from the modern species C.
papyracea by its shell outline.
Family Tellinidae de Blainville, 1814
Genus Leporimetis Iredale, 1930
Leporimetis takaii (Ogasawara and Tanai)

6

Description.-Shell moderate, subtrigonal
to subquadrate, equivalve, inequilateral, andmoderately inflated with twisted posterior
end. Beak prominent and incurved. U mbonal area roundly elevated. Anterior dorsal margin long, slightly arched and connected with widely rounded margin. Posterior dorsal margin short, weakly arched anddescending into slightly truncated its margin.
Well-marked ridge and hollow running frombeak to posterior end, which is twisted.
Surface sculptured with distinct and rather
loose concentric striae. Ligament moderate
and narrow but distinctly marked. Lunulewide and large. Two cardinal teeth distinct
but small. Other inner structures unknown.

4

Valve Length Height Depth H/L D/L
right

24.05

17.00

10.8/2 0.71

right

32.20

24.90

0.77

right

34.20

28.20

right

43.80

34.80

0.22

0.82
9.8

0.79 0.22

32.85

10.04

0.85 0.26

not deform.

28.25

6.6

0.72 0.17

elongated

right

41.40

29.00

9.3

0.70 0.22

right

36+

31.45

deformedconjoined

13.00/2 0.84 0.21

right

31.45

26.55

left

34.60

26+

II

right

32.20

21.40

12

right

36.30

24.55

7.5/2 0.68 0.10

13

right

30.0

22.45 +

12/2

14

right

34.75

25.10

12/2

15

right

28.60

24.50

6.3/2 0.86

16

right

30.90

21.0+

10.0/2

17

left

42.20

29.80

6.7

conjojned

deformed
0.66
compressed

deformed
0.72 0.17

0.71

depressed
depressed

0.16

deformed

0.16

typical form
typical form

18

left

36.60

31.15 13.85/5 0.85 0.19

19

left

37.80

31.00

20

left

36+

31.4

16.0/2 0.82 0.21

ceformed

Loc. Sakashita (lower part)
8.6

0.71

right

31.80

22.65

right

32.60

23.00

0.71

0.27

iii

right

39.50

26.10

13.6/2 0.66 0.17

iv

right

22.00

20.80

0.95

high-type

right

32.0

23.4

6.8/2 0.73 0.11

compressed

vi

right

23.60

18.4

vii

right

30.0

22.4+

0.78
7.0/2

ventral miss.

deformed
0.12

compressed

Loc. Sakashita (upper part)
left

38.25

29.30

0.77

Bright

39.15

26.60

0.68

A

C

right

30.80

24.95

D

right

36.50

30.80

E

right

31 +

6.4

0.81

0.21

16.0/2 0.84 0.22

conjoined

F

right

39.0

13.4/20.17

conjoined

G

right

31.5+

9.4/2

conjoined

H

right

35.85

28.10

13.9/2 0.78 0.19

typical form

right

39.25

30.75

left

39.20

left

33.50

K

0.78 0.22

typical form

30.20

19.3/2 0.90 0.29

very inflated

8.8

12.4/2 0.84 0.17

conjoinedbroken

L

left

36.10

30.20

M

left

27.20

20ea.

N

left

26.80

o

right

23.20

deformed
deformed

17.70

4.5

0.76 0.19

Loc. Oyama Park
right

39.70

31.00

bright32.60

29.60 18.85/2 0.91

right

36.00

27.80

right

27.25

19.2 +

right

23.10

17.55

d
YM no.

38.50
39.30

10

Figures 8-3,-4,-14; 9-21,-23,-25,-26.

Apolymetis (Leporimetis) takaii Ogasawara andTanai, 1952, p. 209, pI. 19, fig. II.
Apolymetis (Leporimetis) nipponica Oyama (MS),Ogasawara and Tanai, 1952, p. 209, pI. 19, figs.
lOa-b; Sasaki and Ogasawara, 1986, pI. 6, fig.
20.
Apolymetis sp., Taguchi, 1981, pI. 3, fig. 2.

left
right

0.78
0.29

12.2/2 0.77 0.17

conjoined
conjoined

conjoined

0.76

Remarks
conjoined
conjoined

Remarks. -This species is characterized
by the ridge running from near beak to posterior end, slightly twisted posterior end andTropical molluscs in the mid-Miocene marginal sea

942.

3'

1237

B

A

. . ••
r

30

..

•
o •

...

10

•

+

2.

;:;..

....

X

"- 20

.:

w

x

+

,.

.-·.
• 1
+2

~

• 3

Q

.
6

,;.

·r

--

4

06

•
-

1
2

··.• 3

• 7

• 6

10

10

"

20

30
2.
lENGTH

3.

40

45mm

0

20

40

3.
30
LENGTH2.

45mm

Figure 6. Relationship between Length and Height (A), and Length and Depth (B) of Leporimetis takaii
Ogasawara and Tanai from various localities. I: Shimoshimizu, Oyama Formation, 2: Lower horizon (B)of Sakashita, Oyama Formation, 3: Upper horizon (A) of Sakashita, Oyama Formation, 4: Oyama Park,
Oyama Formation, 5: Kakehata, Kurosedani Formation, Toyama Prefecture, 6: Sunakozaka Formation,
Ishikawa Prefecture, 7: Tohno, Tamagawa Formation, Ibaraki Prefecture.

distinct fine concentric striae on the shellsurface. The shell with its twisted posterior
end and two small cardinals without lateral
tooth is identical to the genus Leporimetis
Iredale, 1930 (type species: Tellina spectabilis
Hanley) although the genus is very close to
the genera Hemimetis, Tellinimactra andPsammotreta in outline. The genera
Apolymetis and Florimetis are synonyms ofLeporimetis in the opinion of Coan (1971)
and Habe (1977).
Apolymetis nipponica Oyama (MS) illustrated and discussed by Ogasawara and Tanai(1952) is an invalid name because it was only
illustrated, not described. Moreover, A.
nipponica is considered to be an intraspecificvariation of A. takaii, described in the same
paper. Although Ogasawara and Tanai(1952) described the shell inflation in both
species as different, the Height/Length andDepth/Length ratios show a gradual change
within those specimens from the Oyama Formation as shown in Figure 6 (A-B). Thesevariation may be due mainly to deformation
during the fossilization process.
Leporimetis spectabilis lives in sandy bottoms of the tidal zone to more or less than 20

m depth south of Taiwan (Habe, 1977).
The specimens reported under the name of
Apolymetis sp. from the Yatsuo-Kadonosawa
Faunal Province are considered to be thepresent species. Some of them are examined
and measured as follows;
Loc. Kakehata, YalSuo·machi, Toyama Pref. (Kurosedani Formatitn)
No.

Valve

LengthHeight

Depth

H/L

D/L

Remarks

01

right

02

right

30.75

19.90

11.2/20.65

0.18

deformed

38.80

33.90

10.7/20.87

0.14

deformed

Loc. Sunakozaka, Ishikawa Prof. (Sunakozaka Formation)
51

left

33.35

27.00

5.6ca. 0.81

0.17

Loc. Tohno, Ohmiya-machi. Ibaraki Prof. (Tamagawa Formation·)

Loc. no.

Valve

LengthHeight

Depth

H/L

D/L

Remarks

8-1

left

31.20

27.50

8.2

0.88

0.26

no deform

8-1

right

16.70

12.00

E·2

left

19.60

15.60

E-2

right

25.20

19.20

10.4/20.76

0.21

not deform

E-2

right

30.10

25.00

11.4/20.83

0.19

beak miss.

E-2

right

15.00

11.80

0-1

left

40.90

29.90

0.19

deformed

0-2

left

28.2

21.0

0.74
0.73

0.72
0.80

0.79
7.6

0.73

0-3

right

13.20

9.6

C-I

right

37.0

25.40

E-4

right

34.55

26.70

7.0

0.77

0.20

no deform

E-4

right

32.20

22.90

13+/2 0.71

0.2+

conjoined* unpublished collections used

0.69

depressed

1238

Kenshiro Ogasawara and Kazuo Nagasawa

9

Figure 7. (All in natural size). 1,2,3. Cycladicama cf. takey amai (Otuka ), Loc. 1(8). 4. Nitidotellina
kagayamensis (Ogasawara and Tanai), Loc. \(8). 5,9. Macoma sp. , Loc. \(8) . 6a- c, 7a- c,8. Diplodonta!erruginata Makiyama, Loc. \(8). 10. Macoma aff. praetexta (v. Martens), Loc. \(8). lla - b, 12, 13.
Clementia papyracea (Gray), Loc. 2. 14,17. Paphia cf. ohiroi Masuda , Loc. 2. 15, 16, 19. Cyclina japonica
Kamada, Loc. \(A). 18, 20a- c. Anadara (Hataiarca) kakehataensis Hatai and Ni shiyama, Loc. \(A).

942.

Tropical molluscs in the mid-Miocene marginal sea

1239

2a

,

9a
9c

8

13a

13b

Figure 8. (All in natural size ). la - b, 2a - b, 5, 6a- b. Hiatu/a minoensis (Yokoyama), Loc. I(A). 3,4,
14. Leporimetis takaii (Ogasawara and T anai), 3, 14, Loc. 3, 4, Loc. I (A). 7, lIa - c. Vicarya yokoyamai
Takeyama, Loc. I(A). 8. Cerithideopsi//a yalsuoensis Tsud a, Loc. I(B) . 9a - c, 10, 13a- c. CU/lel/us izumoensis Yok oya ma, Loc. 2. 12. Cu /tel/us sp., Loc. I (B).

1240

Kenshiro Ogasawara and Kazuo Nagasawa

942.

Tropical molluscs in the mid-Miocene marginal sea

Family Psammobiidae Fleming, 1828
Genus Hiatula Modeer, 1793
Hiatula minoensis (Yokoyama)
Figures 8-la-b,-2a-b,-5,-6a-b; 9-27.

Soletellina minoensis Yokoyama, 1926, p. 221, pl. 28,
figs. 13, 15, 16; Masuda, 1955, pI. 19 fig. 9 :Kanno, Amano and Noda, 1988, pI. I, fig. 10.
Hiatula minoensis (Yokoyama), Ogasawara andNoda, 1978, p. 36-38, pl.4, figs. 10-12, 15, 17-19,
21, 22; Taguchi, 1981, pI. 2, fig. 12: Ozawa,
Nakagawa and Takeyama, 1986, pI. 14, fig. 4;
Okamoto, Hayashi and Katsuhara, 1989, pI. 6,
figs. 17-18.

Measurements (in mm)
Lac. Shimoshimizu
Call. no.

Valve

LengthHeightDepth

Remarks

001

left

60.60

33.40

ca.5

beak siLUal. 33.3

lert

47.20

24.60

Lac. Sakashita
00-1

1241

pI. 12, fig. 7; Hayashi and Miura, 1973, pI. I, fig.
22; Shibata in Itoigawa et al., 1974, p. 101, pI.
31, figs. 4, 5; Ogasawara, 1976, p.57-58, pI. 14,
figs. 16, 18; Ogasawara and Nomura, 1980, p. 89,
pI. II, figs. 5a-b, 9; Taguchi, 1981, pI. 2, figs. 13,
14; itoigawa et al., 1981-1982, p.104, pI. 20,
figs. 3a-b; Nakagawa, 1989, pI. I, fig. 10

Measurements (in mm)
Loc. Shimoshimizu

Call. no. Valve Length Height Depth H/L

D/L

0001-1

left

86.90

25.20

4.6

0.053

-2

lert

85.0

23.80

7.0/2 0.28

0.041 conjoined

-3

left

79.70

28.00 ca.IO/2 0.35

co.0.063 conjoined

0002-1

left

51.0

17.40

7.3/2 0.34

0.072 conjoined

-2

left

37.5

13.20

7.1/2 0.35

0.095 conjoined

-3

lert

38.70

10.60

2.6/2 0.27

0.085 elongated

0.29

Remarks

Loc. Fujina Formation, Shimane Prefecture
Holotype

left

44.0

15.0

0.34

conjoined

ventral derormed

-2

right

47.50

27.70

co. 14/2

not deformed

-3

right

43.00

19.60

8.1/2

elongated type

-4

right

45.35

23.70

9.4/2

not derormed

Remarks.- This species is usually associated with Vicarya, Anadara kakehataensis
and other characteristic species of the ArcidPotamid Fauna as noted by Noda and Takahashi (1986).
Family Cultellidae Davies, 1935
Genus Cultellus Schumacher, 1817
Cultellus izumoensis Yokoyama
Figures 8-9a-c,-IO,-13a-c; 9-29.

Cultellus izumoensis Yokoyama, 1923, p. 5, pI. 2, figs.
la-b; Yokoyama, 1925, p. 18, pI. 5, figs.2, 3;
Nomura, 1935, p. 220, pI. 16, figs. 16, 17; Otuka,
1941, p. 23, text-fig. 4; Kanno, 1956, p. 213, pI. 6,
fig. 8; Iwai, 1961, pI. I, fig. 19, iwai, 1965, p.45,
pI. 12, fig. 15; Uozumi and Fujie, 1966, p. 153,

Remarks.- Cultellus otukai and C.
oyamensis were both described as new species
from the Oyama Formation by Ogasawara
and Tanai (1952). Both are very similar tothe present species. These two species may
be synonyms, because they were describedbased on deformed specimens, although C.
oyamaensis is more narrowly bladed than C.
otukai. Moreover, their measurements anddescriptions do not agree with the originalillustrations. According to Kanno (1956),
C. otukai is characterized by narrowly bladedshell, and parallel dorsal and ventral margins,and he showed a H/L ratio of about 0.26 and1/4.2-1/4.3 for A/L (length of the anteriorside). However, it is quite difficult to separate these two specimens into different species
without measurements of shell inflation.

~
Figure 9. (All in natural size). 1,6,11. Paphia cf. ohiroi Matsuda, Loc.2. 2, 15, 19. Tellina cf.
notoensis Masuda, Loc. 2. 3,4. Solamen cf. fornicatum (Yokoyama), Loc. 2. Sa-b. Cardilia toyamaensis Tsuda, Loc 2. 7. Vasticardium ogurai (Otuk a), Loc.2. 8, 9. Cycladicama cf. takeyamai (Otuka),Loc. 1 (8), 10,17. Tellina cf. osafuei Taguchi, Loc. 1(8). 12, 14, 16, 18, 20. Macoma aff. praetexta (v.
Martens), Loc.2. 13, 24. Psammacoma aff. awajiensis (Sowerby), Loc.2. 21, 23,25,26. Leporimetintakaii (Ogasawara and Tanai), Loc. I(A). 22, 30. Clementia papyracea (Gray), Loc.2. 27. Hiatulaminoensis (Yokoyama), Loc. 2. 28. Chicoreus cf. tiganourana (Nomura), Loc. 1(8). 29. Cultellus
izumoensis Yokoyama, Loc. 2.

1242

Kenshiro Ogasawara and Kazuo Nagasawa
Class Gastropoda
Family Potamididae
Genus Vicarya d' Archiac
and Haime, 1854
Vicarya yokoyamai Takeyama
Figures 8-7,-11 a-c.

Vicarya verneuili yokoyamai Takeyama, 1933, p.
134-137, pI. 13, fig. 4.
Vicarya yokoyamai Takeyama. Kamada, 1960, pI. 30,
figs.3a-b, pI. 31, figs. 6, 7,10; Itoigawa et al.,
1981-1982, p.168-170, pI. 29, figs. Ila-13b;
Takahashi, 1984, pI. I, figs. 21-23; Sasaki andOgasawara, 1986, pI. 6, figs. lOa-b; Itoigawa andShibata, 1986, pI. 16, fig. 8; Kanno, Amano andNoda, 1988, p. 384-385, pI. 3, fig. I : Nakagawa,
1989, pI. 3, figs. 1-4; Iwamura Res. Group, 1989,
pI. 21, figs. 11-13.
Vicarya (Vicarya) yokoyamai Takeyama. Kamada,
1962, p. 151, pI. 18, figs. 13, 14.
Vicarya japonica Yabe and Hatai. Ozawa, Nakagawa
and Takeyama, 1986, pI. 12, fig. 8.

Remarks.- Two ill-preserved specimens
are examined. One of the specimens preserves 7 whorls and measures 29 mm in diameter and 67 mm + in height. Surface
ornamentation is characterized by three primarily spiral cords and nine horizontally
spired nodes in each whorl except for younger
whorls. These surface spirals compare wellwith the type specimen described by Takeyama (1933) and also the specimens fromthe Kurosedani Formation, Toyama Prefecture. Another specimen (5 whorls preserved,
Max. diameter ca. 17 mm and Height 34mm+) has also three spirals and roundly
elevated nodes just above the suture line.
Vicarya specimens are recorded from the
Ohami Formation in Yamagata Prefecture inassociation with Siratoria siratoriensis andother characteristic species of the Kadonosawa Fauna (Sato et al., 1986).
Genus Cerithideopsilla Thiele, 1929
Cerithideopsilla yatsuoensis (Tsuda)
Figure 8-8

Cerithidea (Cerithideopsilla) yatsuoensis Tsuda, 1959,
p. 84, pI. 4, figs. 2-4; Sasaki and Ogasawara,

1986, pI. 6, figs. 4a-b; Nakagawa, 1989, pI. 2,
figs.4a-b.

Remarks.- Two fragmental specimens are
examined. Surface is sculptured with three
spiral cords and very weak spiral lines justabove the suture. The main spirals haveabout 20 beadlike nodes. These spiral features are well comparable with the type specimen described from the Kurosedani Formation.
Cerithideopsilla minoensis Itoigawa is very
similar to this species but can be separated
from the present species in having about 1316 longitudinal plicae.
Acknowledgments
We would like to express our sincere appreciation to Prof. Hiroshi Noda, Institute of
Geoscience, the University of Tsukuba for his
helpful comments on an earlier draft and to
Dr. Louie Marincovich, Jr. of the U.S. Geological Survey, Menlo Park for his review ofthe manuscript.
Thanks are expressed to Mr. Shohei
Otomo, former Technical Staff of Tohoku
University for his photographic works, andDirector of Yamagata Prefectural Museum
for giving us a chance to examine the molluscan collections of the Oyama Formation.

References
Chiji, M. and IGCP-246 National Working Group ofJapan, 1988: Paleogeographic change andbioevents related to the opening of the Sea ofJapan. Jour. Paleont. Soc. Korea, vol. 4, no. 1.
p.55-60.
Chinzei, K., 1978: Neogene molluscan faunas in theJapanese Islands: An ecologic and zoogeographic synthesis. The Veliger, vol. 21, no. 2, p.
155-170.
- - , 1981: Marine biogeography of Japan during
Miocene: A reconstruction based on benthonicmolluscan faunas. Fossils, no. 30, p.7-15. (inJapanese).
- - , 1982a: Paleoecology of oysters (I). Ibid., no.
31, p. 27-34. (in Japanese with English abstract)- - , 1982b: Paleoecology of oysters (2). Ibid., no.

942.

Tropical molluscs in the mid-Miocene marginal sea

32, p. 19-27. (in Japanese)- - , 1986: Faunal succession and geographic distribution of Neogene molluscan faunas in Japan.
Palaeont. Soc. Japan, Spec. Papers, no. 29, p.
17-32.
- - and Iwasaki, Y., 1967: Paleoecology of shallow
sea molluscan fauna in the Neogene deposits ofNortheast Honshu, Japan. Trans. Proc. Palaeont.
Soc. Japan, N. S., no. 67, p.93-113.
Coan, E.V., 1971: The northwest American Tellinidae. The Veliger. vol. 14 (supplement), p. 163.
Habe, T., 1977: Systematics of Mollusca in Japan.
Bivalvia and Scaphopoda. 372 p. Zukan-no
Hokuryukan, Tokyo.
Hatai, K., 1956: A new Globularia (?) from Yamagat a Prefecture. Saito Ho-on Kai Mus., Res.
Bull., no. 25, p. 1-2.
- - and Nisiyama, S., 1940: A review of thepaleontology of Yamagata Prefecture (Uzen
Province), Northeast Honsyu, Japan. Ibid., no.
19, p. 139-148.
- - and - - , 1949: A new Tertiary Moll usca fromJapan. Jour. Paleont., vol. 23, no. I, p.87-94,
pis. 23-24.
Hayashi, T. and Miura, Y., 1973: The Cenozoic
sediments in the southern part of Okazaki City,
Central Japan. Bull. Aichi Univ. Educ., Nat.
Sci., vol. 22, p. 133-149, pis. 1-2. (in Japanesewith English abstract)
Hayashida, A. and Torii, M., 1988: Opening processof southwestern part of the Sea of Japan- An
attempt of paleogeographic reconstruction.

Gekkan Kaiyo-Kagaku (Monthly Marine Sci.),vol. 20, no. II, p.685-689. (in Japanese; title

translated)
Itoigawa, J. and Shibata, H., 1986: Molluscan faunaof the Setouchi Miocene Series, southwest Japan.
Palaeont. Soc. Japan, Spec. Papers., no. 29, p.
149-159, pis. 16-17.
- - , - - and Nishimoto, H., 1974: Molluscan fossils of the Mizunami Group. Bull. Mizunami
Fossil Mus., no. I, p.43-203, pis. 1-63. (inJapanese)- - , - - , - - and Okumura, K., 1981-1982:
Miocene fossils of the Mizunami Group, Central
Japan. 2. Molluscs. Monogr. Mizunami FossilMus., no.3-A, p. I-53, pis. I-52; Ibid., 3-B, p.

1-330. (in Japanese with English descriptions)- - and Tsuda, K., 1986 :Paleoecological significance of tropical molluscan assemblages inJapanese Miocene, with special reference tomangrove swamp assemblage. Monogr.
Muzunami Fossil Mus., no. 6, p. 171-182. (inJapanese with English abstract)
Iwamura Research Group, 1989: New localities ofVicarya in the Iwamura Basin, Gifu Prefecture,

1243

Japan. Bull. Mizunami Fossil Mus., no. 16, p.
II 7 - 120, pI. 21.
Iwai, T., 1961: The Miocene molluscan fossils fromthe area southwest of Hirosaki City, Aomori
Prefecture. Trans. Proc. Palaeont. Soc. Japan,
N. S., no. 41, p. 1-8, pI. I.
- - , 1965: The geological and paleontologicalstudies in the marginal area of the Tsugaru basin,
Aomori Prefecture, Japan. Bull. Educ. Fac.,
Hirosaki Univ., no. 15, p. 1-68, pis. 12-20.
Kamada, Y., 1960: On the associated occurrence ofVicarya and Vicaryella in the Japanese Tertiary,with the first description of a Paleogene species ofVicarya from Japan. Sci. Rep., Tohoku Univ.,
2nd Ser. (Geol.), Spec. Vol., no.4 (Prof s.
Hanzawa Mem. Vol.), p. 281-295, pis. 30-31.
- - , 1962: Tertiary marine Mollusca from the
Joban Coal-Field, Japan. Palaeont. Soc.
Japan, Spec. Papers., no. 8, p. 1-187, pis. 1-21.
Kanno, S., 1956: Fossil and recent species of thecultellid molluscs from Japan. Sci. Rep., Tokyo
Kyoiku Daigaku, Sec. C (Geol., Mineral.,Geogr.), no. 34, p. 209-218, pis. 5-6.
- - , Amano, K. and Noda, H., 1988: Vicarya andits associated molluscan fauna from the Kunnui
Formation in Oshamanbe, southwest Hokkaido.

Saito Ho-on Kai Spec. Pub. (Prof T. Kotaka
Commem. Vol.), p. 373-389, pis. 1-3.
- - and Ogawa, H., 1964: Molluscan fauna from
the Momij iyama and Takinoue districts, Hokkaido, Japan. Sci. Rep., Tokyo Kyoiku Daigaku, Sec. C (Geol., Mineral., Geogr.), no. 81, p.
269-294, pis. 1-4.
Kobayashi, T. and Horikoshi, M., 1958: Indigenous
Aturia and some tropical gastropods from the
Miocene of Wakasa in West Japan. Japan.
Jour. Geol. Geogr., vol. 29, nos. 1-3, p. 45-54, pis.
Majima, R., 1989: Cenozoic fossil Naticidae (Mollusca: Gastropod) in Japan. Bull. A mer.
Paleont., vol. 96, no. 331, p. 1-159, 14 pis.
- - , and Takahashi, H., 1987: Miocene molluscus
from the Kozono Formation, Saitama Prefecture,
Central Japan. Trans. Proc. Palaeont. Soc.
Japan, N.S., no. 148, p.246-255.
Makiyama, J., 1926: Tertiary fossils from northKankyo-do, Korea. Mem. Coli. Sci., Kyoto
Imp. Univ., Ser. B., vol. 2, no. 3, p. 143-160, pis.
12-13.
Masuda, K., 1955: Miocene Mollusca from Noto
Peninsula, Japan. Part I (I). Trans. Proc.
Palaeon!. Soc. Japan, N. S., no. 20, p. 119-127,
pI. 19.
- - , 1966 : Molluscan fauna of the Higashi-Innai
Formation of Noto Peninsula, Japan. II.
Remarks on molluscan assemblage and description of species. Ibid., no. 64, p.317-337, pis.
35-36.

1244

Kenshiro Ogasawara and Kazuo Nagasawa- - and Noda, H., 1976: Checklist and bibliography of the Tertiary and Quaternary Mollusca
of Japan, 1950-1974. 494p. Saito Ho-on Kai,
Sendai.
Nakagawa, T., 1989: Intertidal molluscan assemblage in the Miocene Kunimi Formation, Fukui
Prefecture, Central Japan. Bull. Fukui Pref
Mus., no. 3, p.23-45, 3 pis. (in Japanese withEnglish abstract)- - and Takeyama, K., 1985: Fossil molluscan associations and paleo-environment of the UchiuraGroup, Fukui Prefecture, Central Japan. Bull.
Mizunami Fossil Mus., no. 12, p. 27-47, pis. 1524. (in Japanese with English abstract)
Nishida, S. and Chihara, K., 1966: Neogene Tertiary
stratigraphy in the Nishitagawa Coal-field,
Yamagata-Niigata Prefecture, north Japan.
Contr., Dep. Geol. Mineral., Niigata Univ., no. 1,
p. 31-57. (in Japanese with English abstract)
Noda, H., 1966: The Cenozoic Arcidae of Japan.
Sci. Rep., Tohoku Univ., 2nd Ser. (Geol.), vol.
38, no. I, p. 1-161, pis. 1-14.
- - , 1973: Geological significance of Anadara(Hataiarca) kakehataensis Hatai and Nisiyama
in the Arcid-Potamid Fauna in Japan. Sci.
Rep., Tohoku Univ., 2nd Ser. (Geol.), Spec. Vol.
(Hatai Mem. Vol. ), no. 6, p. 205-215, pI. 18.
- - , Kikuchi, Y. and Nikaido, A., 1989: ArcidPotamid Fauna from the Tama-gawa River areain Ibaraki Prefecture. Geol. Soc. Japan,
Abstracts with Programs, 96th Ann. Meet., p.
354. (in Japanese)- - and Takahashi, H., 1986: Distribution of
Anadara (Hataiarca) kakehataensis and characteristics of the associated molluscan fauna in theearly Middle Miocene of Japan. Monogr.,
Mizunami Fossil Mus., no. 6, p. 49-58, pI. 5. (inJapanese with English abstract)
Nomura, H., 1935: Miocene Mollusca from
Siogama, Northeast Honsyu, Japan. Saito Hoon Kai Mus., Res. Bull., no. 6, p. 193-232, pis.
16-17.
Oda, M., 1986: Some aspects and problems concerned with microfossil biochronology for the
Neogene in Central and Northeast Honshu,
Japan. Essays in Geol. (Prof N. Kitamura
Commem. Vol.), p. 297-312. (in Japanese withEnglish abstract)
Ogasawara, K., 1976: Miocene Mollusca from
Ishikawa-Toyama area, Japan. Sci. Rep., Tohoku Univ., 2nd Ser. (Geol. ), vol. 46, no. 2, p.
33-78, pis. 11-15.
- - , 1988: Neogene bio-events in terms of warmand cold-water molluscs in Northeast Honshu,
Japan. Osaka City Nat. Hist. Mus., p.49-70.
(in Japanese with English abstract)- - and Morita, R., 1990: A new Miocene gas-

tropod species cooccurred with Paleoparadoxia
specimens from the Yanagawa Formation, Fukushima Prefecture, Northeast Honshu, Japan.
Saito Ho-on Kai Mus. Nat. Hist., Res. Bull., no.
58, p. 25-30, pI. 1.
- - and Noda, H., 1978: Arcid-Potamid fauna(Mollusca) from the Tsukinoki Formation, Sennan district, Miyagi Prefecture, Northeast Japan.
Saito Ho-on Kai Mus., Res. Bull., no. 46, p. 2144, pis. 3-4.
- - and Nomura, R., 1980: Molluscan fossils fromthe Fujina Formation, Shimane Prefecture, Sanin district, Japan. Prof S. Kanno Mem. Vol.,
p. 79-98, pis. 9-12.
Ogasawara, Kenzo and Tanai, T., 1952: The discovery of new Miocene fauna in the northern part ofNishitagawa Coal-field, Yamagata Prefecture,
Japan. Trans. Proc. Palaeont. Soc. Japan, N.
S., no. 7, p. 205-212, pI. 19.
Okamoto, K., Hayashi, Y. and Katsuhara, M., 1989:
Fossil Mollusca from the Miocene at Myoga,
Shobara City, a new locality of Geloina in
Shobara, and the relationship between Tateiwaia
species and substrata-study of the Bihoku
Group 11-. Bull. Mizunami Fossil Mus., no.
16, p. 43-53, pis. 5-7. (in Japanese with English
abstract)
Otuka, Y., 1934: Tertiary structures of the northwestern end of the Kitakami Mountainland, Iwate
Prefecture, Japan. Bull. Earthq. Res. Inst., vol.
12, pt. 3, p. 566-638, pis. 44-51.
- - , 1938 : Mollusca from the Miocene of Tyugoku, Japan. Jour. Fac. Sci., Imp. Univ. Tokyo, sec.
2, vol. 5, pt. 2, p. 21-45, pis. 1-4.
- - , 1941: Fossil Mollusca from Tazima, Hyogo
Prefecture, Japan. Japan. Jour. Geol. Geogr.,
vol. 18, nos. 1-2, p. 21-24.
Oyama, K., 1950: Studies of fossil molluscan
biocoenosis, No.1. Biocoenological studies on
the mangrove swamps, with descriptions of new
species from Yatsuo Group. Rep. Geol. Surv.
Japan, no. 132, p. 1-16, pis. 1-3.
Ozawa, T., Nakagawa, T. and Takeyama, K., 1986:
Middle Miocene molluscan fauna of the UchiuraGroup, Wakasa Province, southwest Japan.
Palaeont. Soc. Japan, Spec. Papers., no. 29, p.
135-148, pis. 12-15.
Ozawa, A., Ohguchi, T. and Takayasu, T., 1979:
Geology of the Asamai district. Quadrangle
Ser., scale 1: 50,000, Geol. Surv. Japan, 53 pp.
pis. 1-4. (in Japanese with English abstract)
Saito, T. et al., 1986: Neogene paleo-magneto-andmicrobiochronological scale of Northeast andCentral Japan. In, Kitamura, N. ed., Cenozoic
Arc Terrane of Northeast Honshu, Japan. 1
suppl. fig. Hobundo, Sendai. (in Japanese; title
translated)942.

Tropical molluscs in the mid-Miocene marginal sea

Sasaki, O. and Ogasawara, K., 1986: Intertidal molluscan assemblage from the Miocene Sunakozaka
Formation, Ishikawa-Toyama area, Hokuriku
district, Japan. Mem. Natn. Sci. Mus, Tokyo, no.
19, p. 79-89, pis. 5-6. (in Japanese with English
abstract)
Sasaki, T., 1991: Molluscan assemblages of the
Sugota Formation from Dewa Hill of Akita
Prefecture. Palaeont. Soc. Japan, Abstracts
with Programs, 1991 Ann. Meet., Sendai, p.34.
(in Japanese .. title translated)
Sato, H., Yamaji, A. and Ishii, T., 1986: Traverse
Route No. 22 of Tohoku Honshu Arc (AtsumiTsuruoka-Obanasawa-Matsushima). 26 pp, I geologic map, I Geologic section map. In,
Kitamura, N. ed., Cenozoic Arc Terrane ofNortheast Honshu, Japan. Hobundo, Sendai.
(in Japanese .. title translated)
Sato, Y., Yanagisawa, Y. and Yamamoto, T., 1989:
Arcid-Potamid fauna of the Myozawabashi Formation, Yamagata Prefecture, northeast Japan.
Palaeont. Soc.. Japan, Abstracts with Programs,
1989 Ann. Meet., Kyoto, p. 83. (in Japanese)
Shimakura, M. and Hatai, K., 1940: Notes on thegeology of the western part of Nisi-Tagawa district, Yamagata Prefecture (Uzen Province),
Northeast Honsyu. Saito Ho-on Kai Mus., Res.
Bull., no. 19, p. 149-152, pI. 6.
Shuto, T., 1960: On some pectinids and Venerids
from the Miyazaki Group (Palaeontologicalstudy of the Miyazaki Group-VII). Mem. Fac.
Sci., Kyushu Univ. Ser. D (Geol.), vol. 9, no. 3, p.
119-149, pis. 12-14.
Taguchi, E., 1981: Geloina/Telescopium bearing
molluscan assemblages from the Katsuta Group,
Okayama Prefecture-with special reference tobrackish faunal zonation in the Miocene ofJapan. Bull. Mizunami Fossil Mus., no. 8, p. 720, pis. 2-4.
Takahashi, H., 1984: Molluscan assemblages from
the Miocene Nakayama Formation in the
Kadono district, Joban Coal-Field, Fukushima
Prefecture. Fossils, no. 36, p. 1-17. (in Japanesewith English abstract)
Takeyama, T., 1933: Notes on the genus Vicarya,with description of two Japanese forms. Japan.

1245

Jour. Geol. Geogr., vol. 10, nos. 3-4, p. 129-144,
pI. 13.
Tanai, T., 1951: Geologic structure of northern areaof Nishitagawa Coal-field, Yamagata Prefecture.
Jour. Geol. Soc. Japan, vol. 57, no. 668, p. 157171. (in Japanese with Latin abstract)
Tsuchiya, N., Ozawa, A. and Ikebe, Y., 1984: Geology of the Tsuruoka district. Quadrangle Series,
scale I : 50,000. Geol. Surv. Japan, 77 pp. (inJapanese with English abstract)
Tsuda, K., 1959: New Miocene molluscs from theKurosedani Formation in Toyama Prefecture,
Japan. Jour. Fac. Sci., Niigata Univ., Ser. 2,
vol. 3, no. 2, p. 67-110, pis. 1-7.
- - , 1960: Paleo-ecology of the Kurosedani Fauna.
Jour. Fac. Sci., Niigata Univ., vol. 3, no. 4, p.
171-203.
- - , 1965: Neogene molluscan assemblages in the
Inner zone of Northeast Japan-with special reference to the Middle Miocene assemblages. Fossils, no. 10, p.20-23. (in Japanese)- - , Itoigawa, J. and Yamanoi, T., 1986: Mangrove swamp fauna and flora in the Middle
Miocene of Japan. Palaeont. Soc. Japan, Spec.
Papers., no. 29, p. 129-134.
Uchimura, R. 1991: Mixed zone of warm- and coldwater species at early Middle Miocene-An example of the Miocene Furanui Formation of Hokkaido. Palaeont. Soc. Japan, Abstracts with
Programs, 140th Regular Meet., Chiba, p. 48. (inJapanese .. title translated)Uozumi, S. and Fujie, T., 1966: Neogene molluscan
fauna in Hokkaido. Part 2. Description of the
Okushiri fauna associated with Vicarya, fromOkushiri Island, Southwest Hokkaido. Jour.
Fac. Sci., Hokkaido Univ., Ser. 4 (Geol. Mineral.), vol. 13, no. 2, p. 139-163, pis. 11-13.
Yokoyama, M., 1923: On some fossil Mollusca fromthe Neogene of Izumo. Japan. Jour. Geol.
Geogr., vol. 2, no. I, p. 1-9, pis. 1-2.
- - , 1925: Molluscan remains from the uppermost
part of the Joban Coal-Field. Jour. Coll. Sci.,
Imp. Univ. Tokyo, vol. 45, art. 5, p. 1-34, pis. 1-6.
- - , 1926: Molluscan fossils from the Tertiary of
Mino. Jour. Fac. Sci., Imp. Univ. Tokyo, Sec.
2, vol. I, pt. 7, p. 213-227, pI. 28.

1246

Kenshiro Ogasawara and Kazuo Nagasawa

Ajiri WJOC, Bihoku 1im~t, Chiganoura T~ / ifIj, Doh ±, Irakawa li+)I[, Kadono )jtll!f,Kakehata fMm, Katsuta ~EB, Kozono .ylil, Kunnui willi, Kunugidaira ff'FJZ, Kurosedani~llJ!;fr-, Kusanagi 1j!~, Nakayama cpW, Ohami :kWJ, Okura :*mt., Okushiri ~OC, Oyama:kW, Sakashita :!:NT, Shimoike Ttl!!., Shiogama m~, Shimoshimizu T1l1f7.K, Shorenji 1=.
ll~, Sugota ~mlEB, Sunakozaka 1i'y.y:!:N, Tamagawa :K)II, Tsurikake ~~, Tsuruoka ~[lUJ, Yanagawa ~)II, Yoshino i§'lI!f, Zempoji ~'3£~.
:;js:fBcp.JtEICP!fJTt!t~=-t>vt 0 i~M*liJ'i,lijHtE 0)~JZ1;f§; *~t:;js:j'I'I~[lUJmO):kLlJ~ J'i,!ijj{tE 0)

flU: W%~~[lUJm ~=-5t;fp-t 01JJ.JtEICP.JtEICP!fJTt!t:kW~0) J'i,!ijj{tE It Geloina, Vicarya, Leporimetis ~tJ: c·~~.7,.., ':::'.hGO)~0)t11=.4&.rtl!tE!j[5t;fp~=-~.-jvtli~fF-f0)~*#Jj~" /'!/ p fifa=-;f§~-t 0$iJ~~ -*- G.h0 0 .:::. O):kW~O) 9/.!ijj{tElt Arcid-Potamid Fauna c c Jb ~=­i*filll*i 1=.n1IIVt.1t~ -c';l; 0 ~ <0) Tellinids (M acoma, Psammacoma, Nitidotellina, Leporimetis) ~iJ~.@:-t 0 $-C'*l&1.-j vt G.h 0 0 .:::. 0) J: ? tdfllVtl¥J*l&1lt.:::. O):I1!!.~iJ~~FI3'*iJ' GI*i-n~~~=-*IEMO)1i'YJ{Vt.JfriJ~~iJ~"?
,t.:$~tl'iffi-t 0 0 t11=.!fb:l1!!.WI¥Jl!V~iJ' G.7,.. 0 C, :*W~ c f.*EB ~ l¥ifill 0) FI3', :& lf~~EREB:I1!!.~O) J:)jtll!f:l1!!.~O)CP W~ c -t- O)~tfillO)FI3' ~=-~I!JjUJ:
J'i,!ijj{tEmlVtJ:O)il';:!l:iJ~~i2/Jb G.h 0 0 .:::. O)il';:!l:IH}].JtEIcp.JtEICP!fJTt!t~=-t>vt 0 ~* c 3I1~*0)
m.li.~1=.!fbgO)~W~':::'.hGo)~K;l;"?kk/JbK1=.CkJbO)c~-*-G.h00~~~[lUJ
mO):*W~a~fF-fO)~*.cp3<f.i~O)~~tfill~=-;f§~ L -C, ,t.: Uaillfli.-jvt G.h 0 0 :;js:illfli-C'lt.:::.
.h G O)~~tlB~=-1JQ -*- -C :kW~t": vt-c'tJ: :;js:fB ii, G.@:-t 0 Leporimetis takaii ~=-C 0) 5t!ijj~I¥J~~ Jb IT"? t.:o<'0"

'J''i'tL~Uilz:9f!~ • :llt7*-a

Trans. Proc. Palaeont. Soc. lapan, N.S., No. 167, pp. 1247-1258, 5 Figs., September 30, 1992

943. FOSSIL DECAPOD CRUSTACEANS FROM THE
MANDA GROUP (MIDDLE EOCENE), KYUSHU, JAPANHIROAKI KARASA W A
Department of Earth and Planetary Sciences, School of Science,
Nagoya University, Chikusa, Nagoya 464-01

Abstract. Five species, Elicalliax yoshihiroi sp. nov., Prohomola japonica (Y okoyam a, 1911) gen. nov., Raninoides nodai sp. nov., Porilinites kallachiensis sp. nov. and
Branchioplax penlagonalis (Yokoyama, 1911) comb. nov. are described from the Middle
Eocene (Okinoshiman) Manda Group in Kattachi, Omuta City, Fukuoka Prefecture,
Kyushu, lapan. The decapod fauna from the Manda Group is closely related to those fromthe western and central Tethyan realms.
Key words. Decapoda, Crustacea, new species, new genus, Manda Group, Middle
Eocene, Kyushu.

Hom%psis japonicus Yokoyama, 1911, andthe palaeobiogeography of the species
involved is discussed.
Specimens prefiixed KMNH IVP are in the
Kitakyushu Museum of Natural History (6,N ishihonmachi 3-chome, Yahatahigashiku,
Kitakyushu, 805), ESN80005 is in the Department of Earth and Planetary Sciences, Schoolof Science, Nagoya University (Chikusa,
Nagoya, 464-01), and others are in the Noda
collection (294, Miike, Om uta, 837).

Introduction
The Middle Eocene Manda Group (Nagao,
1926) is distributed in the Omuta district,Middle Kyushu. This group contains a richmarine fauna and there have been several
palaeontological studies, such as molluscs by
Yokoyama (1911), Nagao (1928), Mizuno(1963) and Tomida et al. (1992) etc., andelasmobranchs by Yabumoto (1989). The
first crabs to be described were Homolopsis
japonicus Yokoyama, 1911 and X anlhilites
penlagonalis Yokoyama, 1911 from the Miike
Coalfield in Omuta City. Tomita et a/.
(1992) figured, but did not describe, three
species of crabs as Oncinopus sp., Carcinoplax sp. and Leucosia sp., all from the Manda
Group.
In this paper, I describe five species, threenew, in five genera of decapods from the
Manda Group, collected by S. Noda. In
addition, Yokoyama's two species from the
Manda Group are redescribed, a new genus,
Prohomola, is proposed to accommodate

Acknowledgments
I thank Professor J unj i Itoigawa of Nagoya
University and Dr. J.S.H. Collins of London
for critical reading of my manuscript. I also
thank Dr. Daniele Guinot of Laboratoire deZoologie (Arthropodes), Museum Nationald'Histoire N aturelle, Paris for useful comments about the new homolid genus, Messrs.
Sakae N oda and Yuei Y oshihiro of Omuta
City for offering the fossil decapod specimens,
and Mr. Yoshihiko Okazaki of the Kitakyushu Museum of Natural History for his useful
information and encouragement during my'Received luly 15, 1992; accepted July 27, 1992
1247

Hiroaki Karasawa

1248

N

t

~Kattachi

AriakeSea

Genus Eucalliax Manning and Felder, 1991

Type species.-By original designation
Callianassa quadracuta Biffar, 1970.
Geologic range.-Eocene to Recent.
Eucalliax yoshihiroi sp. nov.
Figures 2-1--6; 3-1--4

1km

Figure 1.

Locality map.

study.

Locality and geologic note
The Middle Eocene decapods were collected from the Kattachi Formation, Manda
Group exposed at Kattachi (130 28'52"E, 33°
00' 45"N), Omuta City (Figure I). In thisarea, the Manda Group overlying the Om uta
Group, is divided into the Kattachi and
Yotsuyama Formations in ascending order(Nagao, 1926; Matsushita, 1949; Tomida etal., 1992). According to Mizuno (1962,1964), the Manda Group is correlated with
the Okinoshiman stage, set chronologicallyby Ozaki et al. (1991) and Mizuno (1992) inthe late Middle Eocene (Bartonian).
Decapods occur in nodules of the lowermost sandstone of the Kattachi Formation inassociation with many molluscs, Crassatellites fuscus Yokoyama, Venericardia
nipponica Yokoyama, V. mandarica (Y 0koyama), Mazzalina miikensis (Nagao), Perotrochus eocenicus Kuroda and Urata, Aturia
nagaoi Kobayashi, A. matsushitai Kobayashi, and elasmobranchs, Carcharodon nodai
Yabumoto, Striatolamina macrota (Agassiz).
0

Systematic Palaeontology
Infraorder Thalassinidea Latreille, 1831
Superfamily Axioidea Huxley, 1879
Family Callianassidae Dana, 1852
Subfamily Eucalliinae Manningand Felder, 1991

Etymology.- From Yuei Y oshihiro whocollected the type specimen.
Diagnosis.-Chelipeds large, heterochelate ;propodus of major cheliped sparsely granulate on mesial and lateral surfaces; palmslightly broader than long; minor cheliped
slightly shorter than maj or cheliped;
propodus also sparsely granulate on mesial
and lateral surfaces; fingers elongate, longer
than palm; carpus short; merus rhomboidal, with longitudinal carina on lateralsurface.
Description.- The chelipeds are large andheterochelate. The propodus of the majorcheliped is about 1.6 times longer than broad.
The sharp dorsal and mesial margins aredentate. The gently convex mesial and lateral surfaces are sparsely granulate distally.
The palm is slightly broader than long andabout 1.3 times the length of the fixed finger.
The propodus of the minor cheliped is slightly shorter and more slender than that of the
major cheliped. The propodus which is
twice as long as broad bears irregular dentitions on the ventral and dorsal margins, andis sparsely ornamented with granules on thelateral and mesial surfaces, distally. The
palm is about 1.2 times broader than long andshorter than the elongate fixed finger. The
carpus is short. The merus, with a longitudinal carina on the lateral surface, is rhomboidal in lateral view and longer than broad.
The 6th abdominal somite is slightly wider
than long. There are two transverse sutures
extending one-fifth of the width on each sideat the distal third, and they unite with longitudinal sutures. On the posterior margin, acentral suture reaches the horizontal suture.

943.

Decapod crustaceans from the Eocene Manda Group

1249

Figure 2. Eucalliax yoshihiroi sp. nov. 1, branchial region and abdom inal segments, N oda collection(5954), a, dorsal ; b, left view . 2, propodus of right cheliped , paratype (KMNH IVP 300,002), a, latera l ; b,mesial view. 3, propodus of rig ht cheliped , paratype (KMNH IVP 300,003), lateral v iew. 4, propodus of leftcheliped, paratype (KMNH IVP 300,004), latera l view. 5, propodus of left a nd right chelipeds, ho lo type
(KMNH IVP 300,001). 6, right cheliped, paratype (KMNH IVP 300,005). All figures X 1. 5.

1250

Hiroaki Karasawa

Discussion.- The present new species isreadily distinguished from the Late Eocene
Callianassa muratai Nagao, 1932 and C.
elongatodigitata Nagao, 1941 from Hokkaido
in that the palm of the major cheliped isshorter and the minor cheliped is larger.
This species is one of the dominant elements from the Kattachi Formation, Manda
Group.
Repository.-KMNH IVP 300, 001(Holotype); KMNH IVP 300, 002-300, 009(Paratypes); Noda collection (5954).
Infraorder Brachyura Latreille, 1803
Section Podotremata Guinot, 1977
Subsection Archaeobrachyura Guinot, 1977
Superfamily Homoloidea de Haan, 1839
Family Homolidae de Haan, 1839
Genus Prohomola gen. nov.

Type species.-By monotypy Hom%psis
japonicus Yokoyama, 1911 ; Middle Eocene,
Japan; gender, feminine.
Etymology.-Indicating an early memberof the Homola Group.
Diagnosis .-Carapace longitudinally ovate,
tapering anteriorly; dorsal surface flattened,
granulated, without spines; mesogastric lobe
with a median tubercle; rostrum slender,
simple, downturned; pseudorostral spine triangular, short, projecting dorsally.
Discussion.- In the outline of the carapace,
the present new genus resembles Paromola
Wood-Mason and Alcock, 1891 emend.
Guinot and Forges (in press), but differs inhaving the dorsal surface without spines anda short pseudorostral spine which does notoverreach the rostral spine. Prohomo/a gen.
nov. is easily distinguished from the only
other hitherto known Palaeogene homolid
genus Palehomola Rathbun, 1926 because in
Palehomola the rostrum consists of twohorns. Prohomola has pseudo rostral spines
and the mesogastric lobe has a median tubercle, whereas the mesogastric lobe of Hom%psis Bell, 1863 and Zygastrocarcinus Bishop,
1983 has three nodes arranged in a triangle

and there are no pseudorostral spines.

Geologic range.-Late Middle Eocene(Okinoshiman).
Prohomola japonica (Yokoyama, 1911)comb. nov.
Figures 3-5-7

Homolopsis japonicus Yokoyama, 1911, p. 12, pI. 3,
fig. 4.
Paromola japonicus (Yokoyama). Jenkins, 1977, p. 4.
(non Paromola japonica Parisi, 1915)
Oncinopus sp. Tomita et al., 1992, pI. 17, fig. 10.
Zygastrocarcinus japonica (Yokoyama). Bishop and
Brannen, 1992, p. 321.

Diagnosis.-As for genus.
Description.- The carapace is longitudinally ovate in outline and tapers anteriorly.
The forwardly directed rostrum is downturned, slender and simple. The robust
pseudorostral spines are short, triangular, andproject dorsally. The anterolateral margins
with a sharp epibranchial spine, are gently
convex. The irregularly tuberculated
posterolateral margins are gently rounded.
The flattened dorsal surface is ornamented
with granules which vary in size. The
regions are well defined. A deep groove
separates the slightly swollen proto gastriclobes, each with two nodes transversely arranged, from the anterior mesogastric process.
There is a large median tubercle on the slightly convex mesogastric lobe. The inflated
urogastric lobe is bilobed. The narrow cardiac lobe, with a shallow median depression,
is longitudinally vaulted. The cervical andbranchiocardiac grooves are well developed.
Two nodes one above the other are present on
the gently convex hepatic lobe. The gently
elevated epibranchial lobes, divided by ashallow oblique groove, are bounded by thecervical, branchiocardiac and gastrocardiac
grooves. The meso branchial lobes are gently
convex. The metabranchial lobes are separated from the cardiac region by deep postcardiac markings and the intestinal lobe IS
flattened. The linea homolica is present.

943.

Decapod crustaceans from the Eocene Manda Croup

125 1

Figure 3. 1- 4, Euca lliax yoshihiroi sp. nov. 1, sixt h a bdomina l seg ment, paratype (KMNH IVP
300,006), X 2.3, dorsal view . 2, merus of left cheliped, para type (KMNH IVP 300, 007), X 2.0, lateral view.
3, propodus of right cheliped paratype (KMNH IVP 300,008), X J .5. , latera l view. 4, carpus of ri ght cheliped,
paratype (KMNH IVP 300,009), X 2.8 , latera l view. 5- 7, Prohomola japonica (Y okoyama, 1911) gen. nov.
5, ca rapace, N oda collection (5988) , X 2.8, dorsa l view. 5', rostrum of fi gure 5, X 6.2. 6, carapace, KMNH
IVP 300,0 10, X 3.2, dorsal view. 7, plaster cast of outer mo uld of KMNH IVP 300,010, x 4.8, dorsa l view .

Hiroaki Karasawa

1252

Remarks.-Yokoyama's (1911) originaldescription of this species was founded on asingle specimen taken at a depth of 489 feetfrom a shaft at the Miike Coalfield.
Repository.-KMNH IVP 300,010; Noda
collection (5988).
Superfamily Raninoidea de Haan, 1839
Family Raninidae de Haan, 1839
Genus Raninoides H. Milne Edwards, 1837
Type species.-By monotypy Ranina laevis
Latreille, 1825.
Geologic range.-Eocene to Recent.

Raninoides nodai sp. nov.
Figures 4-2-8

Etymology.-From Sakae Noda who collected the type specimen.
Diagnosis .-Carapace longitudinally
ovoid; dorsal surface smooth, with a weak
median ridge; orbitofrontal margin 0.75 ofcarapace width; anterolateral margin withlong hepatic spine.
Description.- The carapace is longitudinally ovoid in outline and the length, excluding the hepatic spine, is 1.5-1.6 times thewidth. The finely granulated dorsal surface
with a weak median ridge, is slightly convex
longitudinally. The regions are not defined.
The posterior gastric pits are present andattractor epimeralis muscle scars are weakly
marked. The wide orbitofrontal margin
occupies 0.75 of the carapace width. The
triangular rostrum is flattened and as long as
wide at the base. There are two deep fissuresin the upper orbital margin and the U-shaped
inner fissure is deeper than the V-shaped outerone. The outer orbital spine is bifid; theexternal branch, directed laterally, is broadly
triangular in outline and longer than the
sharply triangular internal branch. The
inner orbital spine on either side of the rostrum is shorter than the outer orbital spineand directed obliquely outwards. The
anterolateral margins are convex and there isa long hepatic spine projecting forwards andoutwards. Sigmoid posterolateral margins
converge posteriorly. The pterygostomian
regions are inflated and the long buccal area
tapers anteriorly.
Left and right chelipeds are present, butbadly preserved. The propodus has two forwardly directed acutely triangular spines on
the ventral margin and one on the dorsal
margin. The sharp fixed finger is as long as
the palm, strongly deflexed ventrally and has
6 teeth on the occludent margin. The slender dactylus is as long as the fixed finger andstrongly down-curved.
Discussion.- The present new species closely resembles Raninoides vaderensis Rathbun,
1926 from the Eocene of North America, butdiffers in having a weak median ridge on thedorsal surface and a long hepatic spine. R.
nodai sp. nov. appears to have a post-frontal
ridge, but it is much weaker than that of R.
vaderensis.
Raninoides nodai sp. nov. occurs in highdensity conditions at Kattachi.
Repository.-KMNH IVP 300, Oil(Holotype); KMNH IVP 300, 012-300, 015(Paratypes); Noda collection (N676).
Section Heterotremata Guinot, 1977
Superfamily Portunoidea Rafinesque, 1815
Family Portunidae Rafinesque, 1815
Subfamily Carcininae MacLeay, 1838
Genus Portunites Bell, 1858

Type species.-By monotypy Portunites
incerta Bell, 1858.
Geologic range.-Eocene to Miocene?
Portunites kattachiensis sp. nov.
Figures 5-1, 3

Etymology.-From "Kattachi", a fossilbearing locality name.
Diagnosis.- Portunites with nearly straight
frontal margin with 4 blunt lobes, anterolateral margin bearing 5 teeth, the last produced
laterally.
Description.- The carapace is hexagonal in943.

Decapod crustaceans from the Eocene Manda Group

1253

Figure 4. 1. Branchioplax pentagonalis (Yoko yama, 1911) comb. nov., carapace, KMNH IVP
300,017, x 1.5, dorsal view. 2- 8, Raninoides nodai sp. nov. 2, right cheliped, holotype, (KMNH IVP
300,011), x 3.8, lateral view. 3, carapace, paratype (KMNH IVP 300,012), X 3.0, dorsal view. 4, thoracic
sterna and third maxillipeds, para type (KMNH IVP 300,013) , x 2.0, ventral view. 5, carapace and leftcheliped, paratype (KMNH IVP 300,014), X 1.5, dorsal view. 6, carapace, paratype (KMNH IVP 300,015), X
1.5, dosal view. 7, carapace, holotype (KMNH IVP 300,011), X 2.0., dorsal view. 8, carapace, Noda
collection (N676), X 2.0, dorsal view.

1254

Hiroaki Karasawa

outline, the length is about 0.75 of the width.
The finely granulated dorsal surface is moderately convex. The regions are well defined.
The epigastric lobes are transversely ridged.
Broad, deep grooves separate the more convex
protogastric lobes from the anterior mesogastric process and mesogastric lobes. The
gently swollen mesogastric lobe is divided bya shallow median groove. The inflated
urogastric lobe is well defined and there is asmall boss between the urogastric and cardiac
lobes. The cardiac region is hexagonal in
outline; it is subdivided by a shallow median
depression and there are two nodes transversely arranged. A deep cervical groove separates the flattened hepatic lobes from thebranchial regions. The epibranchial lobes
are strongly developed into ridges arching
forwards and outwards to reach the last anterolateral tooth. The otherwise depressedmeso- and metabranchiallobes become tumid
surrounding the cardiac region. The orbitofrontal margin occupies about half of thecarapace width. The frontal margin, separated from a small supraorbital angle by a shallow V-shaped notch, is composed of four
blunt lobes; the inner pair, set close together
to a V-shaped median sinus are separated bya V-shaped notch from the bluntly triangularouter pair. The concave upper orbital margin is pierced laterally by two deep fissures.
Gently arched anterolateral margins have five
well separated triangular teeth; the first fourare directed forwards and the fifth laterally
directed. Gently concave posterolateral margins are as long as the anterolateral margins.
Discussion.-A thin orbital margin, a longanterolateral margin and proto gastric lobes
without transverse ridges easily distinguishthe present new species from Portunites hexagonalis Nagao, 1941 from the Late Eocene
Poronai Formation of Hokkaido. P. kattachiensis sp. nov. resembles P. sylviae Quayle
and Collins, 1981 from the Eocene Barton
Beds of England, but differs in having a wider
carapace, large protogastric lobes and the fifth
anterolateral tooth is strongly projected.

Repository.-KMNH IVP 300,
(Holotype); Noda collection (5927).

016

Superfamily Xanthoidea MacLeay, 1838
Family Goneplacidae MacLeay, 1838
Subfamily Carcinoplacinae
H. Milne Edwards, 1852
Genus Branchioplax Rathbun, 1916

Type species.-By monotypy Branchioplax
washingtonian a Rathbun, 1916.
Geologic range.-Eocene to Oligocene.
Branchioplax pentagonalis(Yokoyama, 1911) comb. nov.
Figure 4-1 ; 5-4-6
Xanthilites pentagonalis Yokoyama, 1911, p. 13, pI. 3,
fig. 3.
Carcinoplax sp., Tomita et al., 1992, pI. 17, figs. 5-8.
Leucosia sp., Tomita et al., 1992, pI. 17, fig. 9.

Diagnosis.-Carapace subquadrate, slightly
wider than long; dorsal surface gently convex; regions well defined by shallow
grooves; frontal margin straight with Vshaped median notch; orbital margin wide;
anterolateral margin with five teeth.
Chelipeds strongly heterochelate, covered
with fine granules.
Description.- The carapace is subquadrate
in outline and slightly wider than long. The
finely granulated dorsal surface is gently convex. The regions are well defined by shallow
grooves. The small epigastric lobes are
gently raised transversely and the proto gastriclobes are gently swollen and well separated
from the slender anterior mesogastric processby rather deep grooves, whereas a boundary
between the proto- and mesogastric lobes is
indistinct. The flattened mesogastric lobe
has two pairs of nodes on either side of the
midline. The urogastric lobe is narrow andseparated from the metabranchial lobes by
deep epimeral adductor muscle scars. The
cervical groove is conspicuous. There arethree nodes set in an inverted triangle on the
gently convex cardiac region. The flattened

943.

Decapod crustaceans from the Eocene Manda Group

1255

Figure 5. 1,3, Portunites kattachiensis sp. nov. 1, carapace, X 2.0, dorsa l view, Noda collection (5927).
3, carapace, ho lotype (KMNH IVP 300,016), X 2.8, dorsa l view. 2,4- 6. Branchioplax pentagonalis (Yokoyam a, 19 11) comb. nov. 2, carapace and left cheliped, Nod a collection (5927) , X 1.2, dorsal view. 4,
cara pace and left cheliped, KMNH IVP 300,01 8, X 1. 5, dorsa l view. 5, left and right chelipeds, thoracic sterna
and abdome n (pl aster cast) , KMNH IVP 300,019, X 1.5, ventral view, 6, carapace, ESN 80005, x 2.0, dorsal
view .

1256

Hiroaki Karasawa

intestinal lobe is small. Gently raised hepatic regions are well differentiated. The
epibranchial lobes are gently swollen andarched anteriorly. The meso- and metabranchial lobes are also gently swollen. The
orbitofrontal margin occupies 0.6-0.7 of thecarapace width. The frontal margin isstraight, divided medially by a V-shaped
notch, and finely granulated, and a shallow
sinus separates it from an obscure inner
orbital angle. The upper orbital margin is
wide and pierced by two shallow notches
laterally. Gently arched anterolateral margins are 0.4 of the width; there are five teeth
including the postorbital tooth; the 1st tooth
is small and triangular in outline; the 2nd is
the largest and broadly triangular in outline;
the 3rd-5th are forwardly directed and acutely triangular in outline, and the 5th is smallest. Gently convex posterolateral margins
are 1.2 times as long as the anterolateral
margins and the posterior angle is broadly
rounded into a slightly convex posterior
margin.
Abdomen of male: The 7th somite is triangular in outline. The 6th, longest, is wider
than long, with straight, parallel lateral margins. The 5th and 4th somites are also wider
than long and their lateral margins taper
anteriorly. The 3rd somite is narrow. The
2nd and 1st somites are not preserved.
Sternites I to 3 are missing and the 4th isbroken; sternites 5 and 6 are wider thanlong; the 7th is narrower than the preceding
two and the 8th is reduced in size.
The finely granulated chelipeds are strongly
heterochelate, the major being rather morethan half as long as the minor cheliped. The
slender dactylus is gently curved ventrally andthere seem to be four teeth diminishing in size
distally on the occludent margin. The fixed
finger is as long as the dactylus and possesses
a longitudinal shallow groove on theventrolateral surface. The palm is longer
than the dactylus.
The pereiopods are ovate in cross section.
Discussion.- Yokoyama (1911) originallydescribed this species on the basis of a single
broken specimen obtained from a depth of
484 feet of a shaft at the Miike Coalfield. Atthat time, he considered the species to be mostclosely allied to Xanthilites bowerbankii Bell,1858 from the Eocene of the Isle of Sheppey,
England. Examination of a recently obtained well-preserved carapace, remaining
associated chelipeds, thoracic sterna and a
fragmentary abdomen indicate that thisspecies should be transferred from Xanthilites
Bell, 1858 to Branchioplax Rathbun, 1916.
B. pentagonalis closely resembles B. washingtoniana Rathbun, 1916 from the Eocene of
Alaska (Rathbun, 1926; Tucker and Feldmann, 1989), but differs in having a longer
carapace and a finely granulated frontal
margin which is separated from an obscure
inner orbital angle by a shallow sinus. A
longer carapace and five anterolateral teeth
readily distinguish B. pentagonalis from B.
concinna Quayle and Collins, 1981 from the
Eocene Barton Clay of England. B.
pentagonalis differs from B. sulcata Muller
and Collins, 1991 from the Late Eocene
Szepvolgy Formation of Hungary by having
well defined dorsal regions of the carapace.
Repository.-KMNH IVP 300, 017-300,
019; ESN80005; Noda collection (5927).

Discussion
The Middle Eocene decapod fauna from
the Manda Group is represented by fivespecies; four species, Callianassa muratai
Nagao, 1932, C. elongatodigitata Nagao,
1941, Ranidina teshimai Fujiyama and Takeda, 1980, and Portunites hexagonalis
Nagao, 1941 have been described from theLate Eocene Poronai Formation of Hokkaido. Except for Portunites, decapods ofthe Manda Group have nothing in common
with those of the Poronai Formation. In
addition, the raninids are represented bydifferent genera.
Both Eucalliax and Raninoides have living
species, while Prohomola, Portunites and943.

Decapod crustaceans from the Eocene Manda Group

Branchioplax are restricted to the Palaeogene.
Whereas the fossil species of Eucalliax and
Prohomola are endemic, those of Raninoides,
Portunites and Branchioplax are recorded
from the Palaeogene of North America, Central America, Senegal, England and Hungary(Rathbun, 1926; van Straelen, 1933; Remyand Tessier, 1954; Quayle and Collins, 1981 ;Muller and Collins, 1991). Accordingly, theoccurrences of Raninoides, Portunites and
Branchioplax show that the decapod faunafrom the Middle Eocene Manda Group isrelated to the western and central Tethyan
realms.
References cited
Bell, T., 1858: A monograph of the fossil malacostracous Crustacea of Great Britain. Part I,
Crustacea of the London Clay. 44 p., II pis.
Palaeontographical Society, London.
- - , 1863: A monograph of the fossil malacostracous Crustacea of Great Britain. Part II,
Crustacea of the Gault and Greensand. 40 p.,
II pis. Palaeontographical Society, London.
Biffar, T.A., 1970: Three new species of callianassid
shrimp (Decapoda, Thalassinidea) from the western Atlantic. Proc. Bioi. Soc. Washington, vol.
83, no. 3, p. 35-49.
Bishop, G.A., 1983: Two new species of crabs,
Notopocorystes (Eucorystes) eichhorni andZygastrocarcinus griesi (Decapoda: Brachyura)from the Bearpaw Shale (Campanian) of NorthCentral America. Jour. Paleont., vol. 57, no. 5,
p.900-911.
- - , and Brannen, N.A., 1992: Homolopsis pikeae,
new species (Decapoda), a crab from theCretaceous of Texas. Jour. Crustacean BioI., vol.
12, no. 2, p. 317-323.
Fujiyama, I. and Takeda, M., 1980: A fossil raninid
crab from the Poronai Formation, Hokkaido,
Japan. Professor Saburo Kanno Memorial
Volume, p. 339-342, pis. 39, 40. Tsukuba.
Guinot, D. and Forges, B.R. de, (in press): Crustacea
decapoda: La famillie des Homolidae de Haan,
1839. In, A. Crosnier, ed., Resultats desCampagnes MUSORSTOM, Mem. Mus. natn.
Hist. nat., Paris.
Haan, W. de., 1833-1850: Crustacea. In, vonSiebold, P.F., Fauna Japonica sive Descriptio
Animalium, quae in Itinere per Japoniam, Jussu
et Auspiciis Superiosum, qui Summum in India
Batava Imperium Tenent, Suscepto, Annis 1823-

1257

1830 Collegit, Notis, Observationibus et A dumbrationibus lllustravit. i-xvii, i-xxxi, ix-xvi + 243
p., pis A-J, L-Q, I-55. Lugduni-Batavorum,
Leiden.
Jenkins, RJ.F., 1977: A new fossil homolid crab
(Decapoda, Brachyura), Middle Tertiary, southeastern Australia. Trans. Roy. Soc. South Australia, vol. 10 I, p. 1-10.
Latreille, P.A., 1825: Entomologie, ou histoire
naturelle des crustaces, des arachnides et desinsects. Genre de Crustaces Encyclopedie Methodique, Histoire Naturelle, vol. 10, 832 p. Paris.
Manning, R.B. and Felder, D.L., 1991: Revision of
the American Callianassidae (Crustacea:
Decapoda: Thalassinidea). Proc. Bioi. Soc.
Washington, vol. 104, no. 4, p. 764-792.
Matsushita, H., 1949: A summary of the Palaeogene
stratigraphy of northern Kyushu. Mem. Fac.
Sci. Kyushu Univ., ser. D, vol. 2, p.91-107.
Milne Edwards, H., 1837: Histoire naturelle desCrustaces, comprenant l'anatomie, la physiologie
et la classification de ces animaux. vol. 2,532 p.
Paris.
- - , 1852: De la famille des ocypodides(Ocypodidae). Second Memoire. Observations
sur les affinites zoologiques et la classification
naturelle des Crustaces. Ann. Sci. Nat., ser. 3(Zool.), vol. 18, p. 128-166, pis. 3,4. Paris.
Mizuno, A., 1962: Paleogene and Lower Neogene
biochronology of West Japan. Part II. Jour.
Geol. Soc. Japan, vol. 68, p.687-693. (inJapanese with English abstract)- - , 1963: Paleogene and Lower Neogene biochronology of West Japan. Part III. Jour. Geol.
Soc. Japan, vol. 69, p. 38-50. (in Japanese withEnglish abstract).
- - , 1964: Paleogene and Early Neogene molluscan
faunae in West Japan. Rep. Geol. Surv. Japan,
no. 204, p. 72 p.
- - , 1992: Reexamination of the biostratigraphic
divisions, Mizuno, 1962-'63, for the Paleogene inwestern Kyushu, based on current age determination data. Geol. Soc. Japan, Abstracts with
Programs, 99th Ann. Meet., p. 179. (in Japanese)
Miiller, P. and Collins, J.S.H., 1991: Late Eocene
coral associated decapods (Crustacea) from Hungary. Contr. Tert. Quatern. Geol., vol. 28, nos. 2,
3,47-92, 8 pis.
Nagao, T., 1926: Palaeogene stratigraphy of Kyushu, Japan. Part 6. Japan. Jour. Geol. Geogr., no.
452, p. 596-601. (in Japanese)- - , 1928: Palaeogene fossils of the Island of Kyushu, Japan. I. Sci. Rep., Tohoku Imp. Univ., ser.
2, vol. 9, no. 3, p. 97-128, pis. 17-22.
- - , 1932: Two Tertiary and one Cretaceous Crustacea from Hokkaido, Japan. Jour. Fac. Sci.,

Hiroaki Karasawa

1258

Hokkaido Univ., ser. 4, vol. 2, no. 1, p. 15-22, pI.
4.
- - , 1941: On some fossil Crustacea from Japan.
Jour. Fac. Sci., Hokkaido Univ., ser. 4, vol. 6,
nos. I, 2, p. 86-100, pI. 26.
Ozaki, M. and Hamasaki, S., 1991: Fission trackages of the Paleogene strata in the northern partof Fukuoka Prefecture, Southwest Japan. Jour.
Geol. Soc. Japan, vol. 97, no. 3, p.251-254. (inJapanese)
Parisi, B., 1915: I Decapodi giapponesi del Museo diMilano. II. Dromiacea. Atti Soc. ital. Sci. nat.,vol. 54, p. 102-116, pis. 2, 3.
Quayle, W.J. and Collins, J.S.H., 1981: New Eocene
crabs from the Hampshire basin. Palaeontology, vol. 24, no. 4, p. 733-758, pis. 104, 105.
Remy, J.M. and Tessier, F., 1954: Decapodes
nouveaux de la partie ouest du Senegal. Bull. Soc.
geol. France, ser. 6, vol. 4, p.185-191, pI. 11.
Rathbun, M.J., 1916: Description of a new genus
and species of fossil crab from Port Townsend,
Washington. A mer. Jour. Sci., vol. 41, p.344346.
Rathbun, M.J., 1926: The fossil stalk-eyed Crustaceaof the Pacific slope of North America. U. S. Nat.
Mus., Bull., no. 138, 155 p, 39 pis.

Straelen, V. van, 1933: Sur des crustaces decapodescenozoiques du Venezuela, Bull. Musee royald'Hist. nat. Belgique. vol. 9, no. 10, p. 1-14.
Tomita, S., Ishibashi, T. and Hara, M., 1992: A briefnote on the Paleogene of the Miike Coalfield in
the Omuta district, Middle Kyushu, Japan. Sci.
Rep., Dep. Earth Planet. Sci., Kyushu Univ., vol.
17, no. 2, p.25-43, pls2-18. (in Japanese withEnglish abstract)
Tucker, A.B. and Feldmann, R.M., 1990: Fossil
decapod crustaceans from the Lower Tertiary of
the Prince William Sound region, Gulf of Alaska. Jour. Paleont., vol. 63, no. 3, p.409-427.
Wood-Mason, J. and Alcock, A., 1891: Note on the
results of the last season's deep-sea dredging:natural history notes from H.M. Indian Marine
Survey Steamer 'Investigator,' Commander R.F.
Hoskyn, R. N., Commanding, no. 21. Ann. Mag.
Nat. Hist., ser. 6, vol. 7, p.258-272.
Yabumoto, Y. 1989. A new Eocene lamnoid shark,
Carcharodon nodai, from Omuta in Northern
Kyushu, Japan. Bull. Kitakyushu Mus. Nat.
Hist., no. 9, p. 111-116, pI. 1.
Yokoyama, M. 1911. Some Tertiary fossils from theMiike coalfield. Jour. Coli. Sci., Imp. Univ.
Tokyo, vol. 27, p. 1-16, 3 pis.

~ffi.fi~~M~~m+~~ • • :m~~*.ffim.~K~~~~~$~~.(#/a~) ~ffi.fi.~. J:: I) ~ L.t-: 3 ~:fl~%tr 5 :fl0)+~~ • • 11::::P-~8G~~ ~o.:.tiL Gft.,

Eucalliax yoshihiroi sp. nov. (7.. T -'£- f/ ~ $1-), Prohomola japonica (Yokoyama) gen. nov.
(;J< -'£- '7 $1-), Raninoides nodai sp. nov. (7 -1j- 1::: ;;If.::. $1-), Port unites kattachiensis sp. nov.
(;tf-tJ' ~ $1-), Branchioplax pentagonalis (Yokoyama) comb. nov. (= /' '::J r7 ;;If.::. $1-) -e;1;~o Raninoides, Portunites, Branchioplax ~O):f?tEft, ~ffi.fiO)+~~ • • 7., r7 TtJ;,~~~~m~,~~mKU~~~$·~$~-~7..~.o)+~~ • • 7"r7T~~~~;1;~k~~~~~om~*~Trans. Proc. Palaeont. Soc. Japan, N.S., No. 167, pp. 1259-1263, 3 Figs., September 30, 1992

SHORT NOTES

29.

PSEUDOSCHWAGERINA SKINNERI, N. SP. FROM NEAR KAMLOOPSIN BRITISH COLUMBIA, CANADA *KIMIYOSHI SADA
Faculty of Integrated Arts and Sciences,
Hiroshima University, Hiroshima 730
and

WILBERT R. DANNER
The University of British Columbia,
Department of Geological Sciences, 6339 Stores Road,
Vancouver, British Columbia, Canada V6T IZ4Carboniferous and Permian limestones ranging in age from late Early Carboniferous to
Middle Permian crop out in the Kamloops
area of British Columbia in Canada. The
Permian fusulinacean faunas in the limestones in this area have been reported byseveral workers (Thompson and Verville,
1950; Skinner and Wilde, 1966; Danner,
1970a, 1970b; Sada and Danner, 1974, 1976,1989).
An Early Permian Pseudoschwagerinafauna was described by Sada and Danner in?

FOREST,===~=,,;;;200 MILES

Kamloops

Figure 1. Map showing the fossil locality in the Ida Lake area (southwest side of McGregor Hill), near
Harper Ranch northeast of Kamloops in British Columbia.
'Received June 2, 1992; accepted July 10, 1992
1259

Kimiyoshi Sada and Wilbert R. Danner1260

1976 from Harper Ranch northeast of Kamloops in British Columbia and included
species Pseudoschwagerina robusta (Meek)
and P. sp. A (Sada and Danner, 1976, p. 217224, pI. 1, figs. 1-2, pI. 2, figs. 1-2). The
Harper Ranch Pseudoschwagerina fauna wascorrelated with the middle Wolfcampian
Pseudoschwagedna fauna of Zone E in the
McCloud Limestone in California (Skinnerand Wilde, 1965).
At this time we describe the unusual speciesof Pseudoschwagerina offered by the late Dr.
John W. Skinner in 1977, which had originally been collected by Danner from limestones cropping out in the Ida Lake area near
Harper Ranch northeast of Kamloops. This
Table 1. Measurements of Pseudoschwagerina skinneri, n. sp. (mm.)
Specimen

UHBHHR-I

UHBHHR-2

FigureLength
Width

I-I

1-2

15.25

16.25
10.05

F.R.
Pro!.

10.00
1.52
0040
0.50

1.61
0.30
0.35

Radius vector
Vo!.
I

0.50

0.25

2
3
4

0.80
1.75
2.70

0.65
lAO
2.75

5

3.55

3.75

6

4.35

4.55

7
5.00
Thickness of spirotheca

5.25

0
I
2
3
4
5
6
7

0.075
0.075
0.056
0.056
0.075
0.113

0.056
0.037
0.037
0.037
0.056
0.075

0.132

0.113

0.094

0.151

speciesis described hereinschwagerina skinned, n. sp.

asPseudo-Description of species
Subfamily Schwagerininae Dunbarand Henbest, 1930
Genus Pseudoschwagerina Dunbar
and Skinner, 1936

Type species.-Schwagerina uddeni
Beede and Kniker, 1924
Pseudoschwagerina skinneri, n. sp.
Figures 2-1-2,3-1

Holotype.-UHBHHR-l (Figure 2-1)
Description.- The shell of Pseudoschwagerina skinned, n. sp. is large and very highly
inflated fusiform with a straight axis of coiling and bluntly pointed poles. The lateralslopes are slightly convex. The shell of theholotype (Figure 2-1) is 15.25 mm. in lengthand 10.00 mm. in width, giving a form ratio of
1.52. The proloculus is large and sphericaland its diameter ranges from 0.30 to 0.50 mm.
The shell is coiled tightly in the inner twovolutions and beyond the third volution
expands rapidly. The radius vectors of thefirst to the seventh volutions in a specimen
illustrated as Figure 2-1 are 0.50, 0.80, 1.75,2.
70, 3.55, 4.35 and 5.00 mm., respectively.
The chamber height is almost the same
throughout the length of the shell except theextreme polar regions.
The spirotheca is composed of a tectum andcoarsely alveolar keriotheca. The spirothecal thickness of the holotype in the first to theseventh volutions is 75, 56, 56, 75, 113, 132,
and 94,um, respectively.
The septa are closely spaced in the first twovolutions and in the third to the last volutions the septa are more widely spaced.
They are fluted in the basal margins andextreme polar areas. The chomata are verysmall in the inner vol utions and indistinct inthe outer volutions.
Remarks.-It appears that the present

29.

Pseudosch wagerina skinneri from Canada

Figure 2. Pseudoschwagerina skinn eri , n. sp.
section , pa ratype, UHBHHR-2, X 10.

1, axia l secti o n, ho lo type, UHBHHR-I , X 10.

126 1

2, ax ial

Kimiyoshi Sada and Wilbert R . Danner

1262

Figure 3.

Pseudoschwagerina skinneri, n. sp. 1, sagitta l section, paratype, UHBHHR-3, X 10.

species is somewhat simi lar to the gen us
Robustoschwagerina in the size of the shel l.
However, it has not the globu lar nor thestrongly umbilicated shell. It is robustly
fusiform in shell shape and has a large
pro loculus. The inner two volutions aretightly coiled and the outer ones are highlyand strongly inflated. From this evidence,the present species can be referred to thegenus Pseudoschwagerina .
In 1976 we reported Pseudosch wagerina sp.
A associated with Pseudosch wagerina robusta (Meek) , Eoparafusulina and corals fromthe Harper R a nch area near Kamloops in
British Columbia. The present species somewhat resembles Pseudoschwagerina sp. A(Sada and Danner, 1976, p. 220, pI. 2, figs. 12). The former species, however, is distinguished from the latter by its larger shell ,larger proloculus, and more ra pid expansionof the she ll.
The present species is somewhat similar to
Pseudoschwagerina robust a (Meek) describedby Skinner and Wilde (1965 , p. 71 - 72, pI. 32,

figs. 14, pI. 33, figs. 1-6) and by Sada andDanner (1976, p. 217 - 219, pI. l , figs. 1- 2) ingeneral outline of the shell. However, theformer species differs from the la tter in hav ing
a larger shell and greater numbers of volution s.
The prese nt species is different from a ny of
the other known species of Pseudosch wagerina by its remarkable she ll.
Locality.- Material came from the so uthwest side of large limestone knob (McGregorHill) just north of Ida Lake and so uth of
Pinantan Lake located northeast of Kamloops .

References
Da nn er, W .R. , 1970a: Carboniferous system of th ewestern Cordillera of so uth eas tern Briti sh
Co lumbi a and northw es tern W as hington .

Compte Rendu, 6th Congress Internal. So·at.
Geol. Carbonif. , vol. 2, p. 599- 608.
- - , 1970b: Paleo ntologic and stratigraphic evidence fo r a nd aga inst sea floor spreading ando pe nin g a nd cl os ing oceans in the Pacifi c N o rth-

29.

Pseudoschwagerina skinneri from Canada

west. Geol. Soc. A mer., Abstracts with Program,vol. 2, no. 2, p. 84-85.
Sada, K. and Danner, W.R., 1974: Early and middle
Pennsylvanian fusulinids from southern British
Columbia, Canada and northwestern Washington, U.S.A. Trans. Proc. Palaeont. Soc. Japan,
N.S., no. 93, p. 249-265, pIs. 35-37.
- - , and Danner, W.R., 1976: Pseudoschwagerina
from Harper Ranch area near Kamloops, British
Columbia, Canada. Com. Vol. Found. Fac.
Integr. Arts and Sci., Hiroshima Univ., p.213228, pIs. 1-2.
- - , and Danner, W.R., 1989: Pseudoschwagerinasp. (n. sp.) from Kamloops area in British Columbia, Canada. Palaeont. Soc. Japan, Abstracts

1263

with Programs, 138th Regular Meet., p.41.
Skinner, 1.W., and Wilde, G.L., 1965: Permian biostratigraphy and fusulinid faunas of the Shasta
Lake area, northern California. Univ. Kansas,
Paleont. Contr., no. 39 (Protozoa, art. 6), p. 1-98,
pIs. 1-65.
- - , and Wilde, G.L., 1966: A new Permian
fusulinid from southern British Columbia,
Canada. A cad. Sci. U.S.S.R., Prob. Micropaleont., no. 10, p. 105-108, pIs. 1-2. (in Russian)Thompson, M.L., and Verville, G.J., 1950: Cache
Creek fusulinids from Kamloops, British Columbia. Contr. Cushman Found. Foram. Res., vol. I,
p. 67-70, pI. 8.

1264

PROCEEDINGS OF THE PALAEONTOLOGICALSOCIETY OF JAPAN

Palaeontological Society of Japan (PSJ) Council Actions
During its meeting on June 20, 1992, the PSJ Council enacted the followingchanges to its membership.
New members elected:
Hitoshi Furusawa,
Norio Kito,
Naoko Nikkawa,
Takayoshi Okajima,
Hiroshi Sawamura,
Georg Waldmann.

Hajime Honma,
Yolanda o. Maac,
Shinichi Nishinosono,
Kenichi Okushi,
Yayoi Shinada,

Yasuaki Isomura,
Nobuo Majima,
Akira Okajima,
Shinji Satou,
Tatsuya Takahashi,

New patron members;
The Kiseki Museum of World Stones,
Social Education Division, Itoigawa Municipal Board of Education.
Resigned members;(Fellow)
Kazuo Ohmura(Ordinary members)
Sumito Mizushima,
Noriko Nakazato.

Tsutomu Utashiro,

Jean Vannier,,._._._. ___ . ___ ._._. ___ . ___ . ___ ._._.4

fr •

~

JE .--.-----------.-.---.---.-.---.-.-.)

\

\

I

I
\

\

©1993 4-4-~ • ~~vi, 19934- 1 }j 29 B, 30 B, 31 B K.miEl:*:'¥:'C'lmft ~:h 'i -t a ~iJ&
$j6vi 12}j 10 B (~'l!f) frUm'C·-to ~iJ&$j60Y1Ji$I.J:~£vctJ:"?""(\"i-to ~L <vi
f1r.::fiJ 48"%~;:'~r~\"o©1993 4-{7U~ (~142 @]{7U~) vi, :*:~:fY:W:*:,¥:'C' 6 }j 1&*"vclmftO)T~'C'-t a

1
l
l
!
\

I
\

I

1
l
l
!
\

.
I
I

l
!

l
!

$j65t :\

=r 422~IlDlJJjU¥llDlm:*::fr 836~1lDl:*:,¥:lJ.'¥:-ffll:itl!.:£;I(W'¥::fY:'¥:

1

Fax. 054 (238) 0491l?lli:fr1WZ (P9~ 5801) ~tlE 7$ (P9~ 5810)

fi' 054\(237) 1111

1
(h~1*)\

I.l
I~.---.-------~---.-------------------~---.---------------~-----------------~-------~---~~~~~~(1991-1992)~Uffit::fiUffit 00 1m

1Jrnll 1z:g
i¥J~

fJ83
~;jljD

*~

h.Kt

'HR

t?r

~

§

$"l

~~

7$5

Wl-ffll -gX;';tIE (~ It:/lt)MM'M83 ¥J't

5fp~*~~~fl~~~6.mli, ~.~~.W~~, ~-ffll.M~~~.MM~~~lj~.M~.~~~~.il~~l ~n l~; ~ ~o fJ1.:tE~.M~.'j:r~cO)iffi t) l"~o*ffi.!,Jllm~W~.~~W~-1 /' F;:t, y 7EiEIl1*J:t~t±

I~Uft ~ ?t. ff A 1* J:t ~ t±ug
7" -1 ..y ::J /' -lj" }v 7' /' r-;Jt:tLHlm:V: § ?t.~~~ug'iff 00 E ffiI 1* J:t ~ :t±::fiiEll~imirm~1*J:t~t±

~

::fi

~

~

-=#::fiiElllm~1*J:t~t±

9€ h

1992~

9 Jl 25 13

~p

~~

1992~

9 Jl 30 13

96

IT

ISSN

0031-0204

l3*il:1.¥!.J~~¥fH5-· *c~~~

1 6 7 %
2,500 fIl

B M; E iEIl 1m ~ (W :j5tH~t g:~( 7 -1 '7.x.;t JIOO[)~

B* tl :1. il'm "tT'1l3:l!!:Ji\1'lIl*~j6 5 -~1 6- 913*~~~~-t:/;Jl-1*J
~

~

~

~

~~~~
~p

ftilU

~

~

03-5814-5801:miii1tlE·
Ji'I,

*

~

@:

I§ )lJ,iw ir m:5 it IR r:. T!l) El lI§ IBJ 8-45
t!t~I±l~~~~1*~~tl:

t!t~~~*tl: 022-288-5555 :l!!:Ji\ 3455-4415

Transactions and Proceedings of the PalaeontologicalSociety of Japan

New Series No. 167

September 30, 1992

CONTENTS
TRANSACTIONS
940. Yasufumi Iryu: Fossil nonarticu1ated coralline algae as depth indicators for
the Ryukyu Group .................................................. 1165
941. Kazuhiro Sugiyama: Lower and Middle Triassic radiolarians from Mt.
942.

943.

Kinkazan, Gifu Prefecture, central Japan .............................. 1180
Kenshiro Ogasawara and Kazuo Nagasawa: Tropical molluscan associationin the Middle Miocene marginal sea of the Japanese Islands: An example ofmolluscs from the Oyama Formation, Tsuruoka City, Northeast Honshu,
Japan .............................................................. 1224
Hiroaki Karasawa: Fossil decapod crustaceans from the Manda Group(Middle Eocene), Kyushu, Japan ...................................... 1247

SHORT NOTES
29.

Kimiyoshi Sada and Wilbert R. Danner: Pseudoschwagerina skinneri, n. sp.
from near Kam100ps in British Columbia, Canada ...................... 1259

PROCEEDINGS .......................................................... 1264