ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 145

Pa laeonto logi ca l Society of J apan
April 30, 1987

Co-Editors

Hisayoshi IGO and Tsunemasa SAITO

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

All communication relating to this journal should be addressed to the

PALAEONTOLOGICAL SOCIETY OF JAPAN% Business Center for Academic Societies,
Yayoi 2-4-16, Bunkyo-ku, Tokyo 113, Japan

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 145, pp. 1-9,5 Figs., April 30, 1987

825. LITTLE KNOWN AMMONITE GRANDIDIERICERASFROM HOKKAIDO(STUDIES OF CRETACEOUS AMMONITES FROM HOKKAIDO-LVIII)*TATSURO MATSUMOTO
c/o Department of Geology, Kyushu University 33, Fukuoka 812

and
RINJI SAITO
S. G. Giken, 2-11 Ono-ue, Kumamoto 862

Abstract. The ammonite genus Grandidiericeras of the Puzosiinae (Desmoceratidae)
was represented by only a single species which occurred rarely from the Campanian (Upper
Cretaceous) of Madagascar. We describe in this paper another new species on the basis of several
large specimens obtained or observed years ago from the Coniacian of the Ikushumbets district,
Hokkaido. This denies the previous thoughts that the genus was a special offshoot of the
Puzosiinae in a local province, although we should search for more material and reliable evidence to make clear its phylogenetic origin.

Introduction

Palaeontological descriptionMore than 50 years ago one of us (R. S.)
was devoting himself to a study of Cretaceous
strata and ammonites of the Ikushumbets (nowcalled Mikasa) district when he was a student of
Hokkaido University (Sapporo). The results
were written in two volumes of manuscripts
which have not been published but kept in
the university. Taxonomic results in them
are now out of date and some of the collected
specimens are missing. There is, however, alarge ammonite which has been kept carefully.
This has been noticed by the other of us (T. M.),
who has recently studied it in comparison witha similar ammonite stored in Tohoku University (Sendai). In due course, we have cooperated
with each other to replenish the old collections
with new knowledge that the large ammonites
are referred to Grandidiericeras, little known
genus of the Puzosiinae. This paper is to describe
the result of our study.

Family Desmoceratidae Zittel, 1895*

Received March 19, 1986; read June 15, 1986 at
Kitakyushu Museum of Natural History.

Subfamily Puzosiinae Spath, 1922
Genus Grandidiericeras Collignon, 1961
Type species: -Grandidiericeras grandidierorum Collignon, 1961 by original designation.
Diagnosis:-Fairly involute and rather narrowly umbilicate shell, with high whorl andnarrowly arched venter. Numerous crowded
ribs of unequal length but of similar strength;
long ones arising at or near the umbilical rim
and gently flexuous on the flank; shorter ones
branched or intercalated at various points ofthe flank; all the ribs curved forward on theouter part to a certain degree depending on
species. Constriction absent or very faint onouter whorls.
Body-chamber of large macroconch may bebroadened, with divergent flanks and broadly
rounded venter, and smooth on the surface.
Suture similar to that of Puzosia, being finely
and deeply incised in mature shell.

Tatsuro MATSUMOTO and Rinji SAITO

2

Comparison and remarks: As Collignon(1961) pointed out, this genus is similar toAustiniceras in shell-form, but it does not showsuch a distinct differentiation of major andminor ribs as that of Austiniceras. It seems
to have a peculiar shell-form of macro conch.
It is distinguished from Mesopuzosia in its
more involution and absence or faintness ofconstrictions in the main part. Its phylogenetic
origin is uncertain, although it was regarded by
Collignon as an offshoot from Austiniceras.
The genus is represented at present by a few
species.
Grandidiericeras nagaoi sp. nov.
Figures I, 2, 3-la-Ic, 4-la-Ib

Holotype:-GMH. No. 12008, obtained by R.
Saito in 1932 from the green sandstone (GS2of Matsumoto, 1965; 1984) at loco Ik 966d on
the River Ikushumbets, about 500 m downstream from the mouth of the tributary called
Kami-ichi-no-sawa, Mikasa district.
Paratype:-IGPS. 98917, without locality record, but its rock matrix is very similar to thatof the holotype.
Diagnosis: -Shell very large, consisting of
fairly involute whorls which expand with highratio. Umbilicus narrow for the subfamily,
encircled by steep or nearly vertical wall. Whorl
higher than broad, elongated ovoid in section,with subrounded umbilical shoulder and gently
convex flanks which converge gradually torather narrowly arched venter.
Ribs gently flexious on flanks, moderately
projected on venter, numerous and crowded,
consisting of longer and shorter, branched orintercalated ones. No constriction on the obTable 1.

servable last whorl of the phragmocone.
Suture of Puzosia pattern, having asymmetrically tripartite, large L, which is much
deeper than E, smaller and oblique U2 and remarkably descending auxiliaries (suspensive lobe,
U3=S).
Body-chamber of probable macroconch muchdifferent from phragmocone in having nearlysmooth and broad shell with divergent flanks
and broadly rounded venter.
Observation:- The holotype is wholly septate
and the umbilical seam of the succeeding fullone whorl is traced. Should the umbilical ratio(UID) be assumed as 0.21, the entire shellwould be about 900 mm in diameter. The
para type is somewhat larger than the holotype,but still septate.
The ratio of the increase in height is 1.73
and that of radius 1. 71 per half a whorl in theholotype. This is very high for the subfamily.
Moreover, the outer whorl overlaps two thirds(in height) of the inner whorl. Accordingly, theumbilicus is narrow for the subfamily Puzosiinae,
being 21 to 20 percent of the shell diameter inthe holotype. The expansion ratio of the whorlheight is smaller (1.55) and the umbilical ratio(U/D) is somewhat larger (0.24) in the para type.
This can be regarded as variation.
For some reasons the inner nuclear part ofthe shell is not well preserved in these two
specimens. As far as the well observable outerwhorl of the phragmocone is concerned, there
are no periodic constrictions nor flares. This isunusual for the Puzosiinae, but a low flare which
probably corresponds to a constriction is seenon the inner whorl of the paratype at a point390" preceding to the preserved end.
The ribs are numerous. In the holotype

Measurements (in mm).

Specimen

DiameterUmbilicus

HeightBreadth

B/H

GMH 12008 (1)GMH 12008 (2)IGPS98917( -180°)348.5 (1)290.0 (I)545.0 (1)380.0 (1)70.0 (.20)
61.0 (.21)
133.0 (.24)-100. (.26)

176.5 (.51)
142.0 (.49)
250.0 (.46)-170.0 (.45)-120 (.34)-97 (.33)-168 (.33)

0.68
0.68
0.67
>0.56

(1) at M in Figure 1; (2) at m in the same figure; -: approximate>95825. Little known ammonite Grandidiericeras

Figure 1. Grandidiericeras nagaoi sp. nov.
Diagrams of the holotype: lateral view (A) and whorl-sections (B, C) at M and m. M, m: Two positions ofmeasurements. a and b-c: two places where injury is traced. Scale bar: 20 mm.
(T. M. & R. S. delin.)3

4

Tatsuro MA TSUMOTO and Rinji SAITO

they number 60 on its venter within a half
whorl up to point M and 55 up to point m.
They are of unequal length, crowded and nearlyas narrow as or slightly narrower than the interspaces. Long ribs arise from near the umbilicalmargin but are not stronger than shorter ones.
The shorter ribs are intercalated between or
branched from the longer ones on the outerand also on somewhat inner parts of the flank.
The mode of ribbing of the paratype looks
similar to that of the holotype, although it issomewhat obscured on the weathered internalmould.
The ribs are gently flexuous on the flankand moderately projected on the venter. On theleft side of the holotype the normal curvatureof the ribs are modified by injuries, at a in
Figure 1 and for about 90° from b to c in thesame figure. This is a rather rare case, since
examples of injured large ammonites of the
Puzossinae are very few in our experience,
although we know more examples of injured
small shells. The paratype has no sign of injury.
Regrettably the smooth body-chamber was
not brought back to the institution. There was,however, another huge specimen embeddedin the same sandstone. Its phragmocone wasquite similar to the holotype, but its bodychamber was extraordinarily broadened, withdivergent flanks and a broadly rounded venter,as shown in Figure 2, and was nearly smoothon the surface. This specimen is now missing
from the University of Hokkaido Collection.
Comparison and discussion:-On the groundof compressed and fairly involute shell, modeof ribbing and the absence of constrictions
or flares on the ribbed outer whorl, this species
is assigned to the genus Grandidiericeras Collignon, 1961. It is, however, much larger andless compressed than the type species, G. grandidierorum Collignon.
One of us (T. M.) once studied the holotypeof that species (Collignon, 1961, pI. 17, figs. 1,
la; this paper Figure 5), MHN. 3915, from
the Middle Campanian of Madagascar. Its dimensions at about 30° behind the preserved end
and D=149.4 (1), U=41.0 (.27), H=65.2 (.44),

Figure 2. Grandidiericeras nagaoi sp. nov.
Cross-section of another large specimen fromthe type locality. Inner whorls may be somewhat distorted. Scale bar: 50 mm. (R. S. delin.)

B=31.5 (.21), B/H=0.48. The preserved lastpart of the body-chamber is somewhat deformed. At about 90° behind the preserved
end in the undeformed part B/H is 0.54, being
still smaller than that (0.68) of our specimens.
The flanks are rather flattened and the venteris narrowly arched in the Madagascar specimen
as in typical examples of Austiniceras. Owing
to unfavourable preservation, the absence or825.

Little known ammonite Grandidiericeras

Figure 3. Crandidiericeras nagaai sp. nov.
Lateral (la) and ventral (lb) views of the holotype, GMH. 12008 from loco lk 966d Cof T. M.) , co llec ted by R.
Saito ; scale bar: 50 mm ; part of sut ure (I c) drawn by R. S. scale bar: 20 mm.

56

Tatsuro MATSUMOTO and Rinji SAITO

Figure 4.
Grandidiericeras nagaoi sp. nov.
Lateral (la) and frontal (lb) views of the para type, IGPS. 98917; scale bar: 50 mm.

825. Little known ammonite Crandidiericeras
presence of constrictions on the inner whorlsof the holotype is not clearly observable. Anyhow, our species is distinct from the species
from Madagascar.
Desmoceras montisalbi Laube et Bruder,1887 (p. 222, pI. 24, figs. 1a, b), from theTuronian of Bohemia, was regarded by Collignon
as possibly Crandidiericeras, but listed underAustiniceras in another page. Its holotype isabout 40 cm in diameter and smaller than ours.
It seems to have major ribs and accordingly it
is probably a species of Austiniceras. In fact,
Wright and Kennedy (1984, p. 60) listed D.
montisalbi as a synonym of A. austeni, although
the Bohemian specimen seems to be too muchsecondarily compressed for precise identification.
As in the case of Puzosia and Mesopuzosia,
a dimorphic pair must exist in Crandidiericeras.
The holotype of C. grandidierorum is not verylarge, about 150 mm in diameter, but has abody-chamber. Presumably it may represent
an adult microconch, although its apertural
margin is not preserved. We presume that themacroconch of that species is larger and may
have a broader and smoothed body-chamber,as suggested by our example. This should however, be examined by the actual specimen to
be searched for in the future.
In the case of C. nagaoi, the large specimens
described by us must have been macro conchs.
Especially, the much broadened body-chamber
illustrated in Figure 2 suggests to us that it isa mature female shell which may have contained
a large egg or a number of eggs. Then, what
was the micro conch which made a pair withthis macro conch?
In the Coniacian of Hokkaido, Mesopuzosia
yubarensis (limbo) occurs fairly commonly.
It is seemingly similar to the phragmocone of
C. nagaoi in the compressed and fairly involute
shell-form and numerous ribs. On the average,
it has a more compressed whorl and wider umbilicus and its ribs are more remarkably projectedon the venter. Moreover, the periodic constrictions and flares persist to the adult stage in
M yubarensis as in other species of Mesopuzosia.

7Grandidiericeras grandidierorum
Collignon.
Whorl-section of the holotype. Scale bar: 10mm.
(T. M. delin.)
Figure 5.

The large body-chamber of its probable macroconch has not divergent flanks but is suboval
in cross section as in other Mesopuzosia. Thus M
yubarensis has no relation to C. nagaoi. We
should search for the microconch of C. nagaoi.
Occurrence: - The locality of the holotype
collected by R. Saito is the same as loco Ik
966d of Matsumoto (1965, fig. 2). The exposed
bed is the green sandstone (marked as GS2)
above the zone prolific of Reesidites minimus(Hayasaka et Fukada) and assigned to the baseof the Conician by Matsumoto (1984, fig. 2).
The bed cropped out above the running waterof the River Ikushumbets, but it is now submerged under the artificial lake of the Katsurazawa dam. Another specimen illustrated in
Figure 2 was also in the same bed and Matsumoto also found still another large specimenof probably the same species at the same locality.
It is worthy to note that several huge individuals
were embedded in the green sandstone of a
restricted exposure. This bed is intercalated
between finer silty sediments. It may be allowed
to imagine that an environment of somewhat
shallow sea with sandy bottom may have beenfavourable for mature females of this species
to come in to set their eggs attached to algae
or something grown on this substratum andthat they may have died for some reason at
this place.

8

Tatsuro MATSUMOTO and Rinji SAITO

More specimens should be searched for inother places.
Concluding remarks
Although most genera of the Puzosiinae occur
commonly and show a widespread distribution
in various regions of the world, Grandidiericeras
has been reported very rarely. It was represented
by only two specimens of one species from theCampanian of Madagascar. This situation andits peculiar characters have given us thoughtsthat it may be a local and special offshoot in
the evolutional history of the Puzosiinae.
Now the genus includes at least two species,
its distribution is extended to Japan and its
stratigraphic range downward to the Lower
Coniacian. The mode of occurrence of thedescribed species in Hokkaido denies its true
rareness and the scarcity of available specimens
are probably due to our inadequate collection.
In other words, we should search for morematerial and reliable evidence to make clear thephylogenetic origin of this kind of little known
ammonite.
Acknowledgements
This species is dedicated to the late Professor
Takumi Nagao who gave us instructive suggestions when we started to do a research work.

We owe much to Professor Makoto Kato of
Hokkaido University and Professor Tamio
Kotaka of Tohoku University who have afforded facilities for this study, and to Mr. Sumio
Kumano, Dr. Kenshiro Ogasawara and Mr.
Shohei Otomo for their kind help in the respective institutions. Miss Yoshimi Tanigawa assisted
us in preparing the typescript.
Repositories:-Abbreviated as follows in thispaper: GMH. Geological & Mineralogical Collections, Hokkaido University, Sapporo; IGPS.
Institute of Geology and Palaeontology, Tohoku
University, Sendai; MHN. Museum Nationald'Histoire Naturelle, Paris.
References cited
Collignon, M. (1961): Ammonites neocretacees duMenabe (Madagascar). VII-Les Desmoceratidae.
Ann. Ceo I. Madag., vol. 31, p. 1-115, pis. 1-32.
Laube, G. C. and Bruder, G. (1887): Ammoniten derbOhmischen Kreide. Palaeontographica, vol. 33, p.
215-239, pis. 23-39.
Matsumoto, T. (1965): A monograph of the Collignoniceratidae from Hokkaido. Part 1. Mem. Fac. Sci.
Kyushu Univ., Ser. D, vol. 16, no. I, p. 1-80, pis.
1-18.
- - (1984): The so-called Turonian-Coniacian boundary in Japan. Bull. Ceol. Soc. Denmark, vo!. 33,
p. 171-181.
Wright, C. W. and Kennedy, W. J. (1984): The Ammonoidea of the Lower Chalk. Part 1. Monogr.
Palaeontogr. Soc., London, p. 1-126, pis. 1-40
(Pub!. no. 567, part of vol. 137 for 1983).

Hokkaido ~tiilJjt[, Ikushumbets Okushunbetsu) ~l1AF~Ij, Kami-ichi-no-sawaza wa niJi, M i kasa ~Jf..

J:-O)ir(, Katsura-825. Little known ammonite Grandidiericeras~tiflf.jililli~:ojd!\);117 /-9'f:+ -{ r Grandidiericeras . .: (7)/iI!,li"7 9'"-1/7, -I; J\'-(7)I-_ifl\lJ'IEif~-I; /- /{c::.. 7 /- illi(7) 1 HU: W"':f~ Coil ignon( 1961) fJ' Puzosi inae (7) 11m; i:: L -tiltHIII Lt.:fJ\ filil:~WIJfJ{'J

BI il -C \' 1;,:fJ'"" t.:o t.'iIiM'~t k{l:r-{:~ II,H-f:* UlfJE L t.: t;'{:f.: 1l1.1f" {- (7)fili-t tH.:fJ'fl},f;)tM L, 4,I,i,(7) f:l ,f..:I:t;lt ~~f9IJ i:: ;,.1;,: L -C': ':I:~~<I&L t.:o 'Ifi~~ -('~~;I~iI*Jrl(ljIH~JlI11f~, f<:~:i(7)lj}jfJ'J,Wx:'il'nj~ L, :I~i A x Ii 'J}-Ilrj( (7) ~'.fIj1J j: I) L :t",IJ}} Ii -'<"-'<" J, \' fJ' {- (7)1;iJl ~ I:}.:ib'J't:,.· <. Y < L 1& WJI: Ii <(FilfJ'9€jfLt:,.·\,~,,f..:I,~(7)~;J·I'I:-tij;-to f~:rt:Hi G.grandidierorumCollignon j: I) Lli~fJ'
I::k~
J!*f~i(7)*MfJ'-'<'" 11.;\'0 tEiJ§-C--li'jj}li~~fl:i)~:'kL, rp"ifJ')1.}jI:IIIJlt-Clfl:kL -CIl:, ')1.)fli'!-L-")f;J¥/;t:,.·1f~;IX'!-lE_-t~o fI,UI:Hii::li)]IJHi-C-, G.nagaoisp.nov. C Lt.:o Puzosia-'<" Mesopuzos i a (7)t~g. i:: fiiJfilll:, :f.:MrI,l: L :k 2 '\'1 (7) d i morph i sm fJ';h ~ t:,.. G, .:.: I: ¥fH'-f(7)~ WIJli"77o::J /- 7-C--;h 7) -j LfJ' U-Jrc,-t ~ :: 7o::J:'- 7Ii*if-C'";h ~ottlll 5" .L.-W~;t~IH: ~lr#~1J III ,f..:i*t '!- Witfili-t ~ Ue!i'J;'6!l'J (I oc. Ik966d (7) GS 2) '1' I: Hl!&fllilf$:ilI':
L t.:(7)/iHillilli Matsumoto(l984) fJ'-::J c::.. 7::.--7:.- (7)+£!l'l;ffl, i:: L t.: L (7) -C'";h ~"7 Kh -C" L B I$: -Co L Grand id i e ri ce rns (7)Jt';(B~M!tII(7)·I1:;tI\fJ':.t;;lil' -C";h I), .: (7) t.: Y:l I$:I,~(7) ~il*-'<"ifd"cJ::(7) f3i:ill!'-")"lt Ii all G fJ' -C'"t:,.. \' i t.: m:rt: tof((7) "7 7 0 ::J :.- 7 (7)foiJJ.f(7)·11:;ll\fJ'*~ t:,.-.: i:: L ,j\]
/1, -C, "fi&(7)-!*1'l:fJ'.!6·-'?t-r;h ~t~4:jf!'ll\ . mJiH.j;)-:

<,

+

0

0

.:

0

0

0

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 145, pp.10-15, 3 Figs., April 30, 1987

826. POIKILOSAKOS (OLDHAMINIDINA, BRACHIOPODA)

FROM THE PERMIAN OF NORTHEAST JAPAN*
JUN-ICHI TAZAWA
Department of Earth Sciences, Faculty of General Education,
Niigata University, Niigata 950-21

and
YUKIHIRO T AKAIZUMIKoyodai 4-33-22, Izumi, Miyagi Prefecture 981-31

Abstract. The oldhaminoid brachiopod genus Poikilosakos is recorded for the first timefrom the Japanese Permian. The new species Poikilosakos kamiyassensis is described from theMiddle Permian Kanokura Formation (Member KNl) of Kamiyasse, southern Kitakami Mountains, northeast Japan. This species is a large, transversely wider Poikilosakos that may be anadvanced form, closely related to Poikilosakos tschernyscllewi Fredericks, 1926 from theLower Permian of the central Ural Mountains, U.S.S.R.

. septata, Verbeekina verbeeki, Codonofusiella explicata and Parawelltzelella(Parawentzelella) canalifera;
KN2: Sandstones and arenaceous or argillaceous, impure limestones (150 m),
with numerous fossils of fusulinids
and brachiopods such as Monodiexodina matsubaishi, Chusenella chosiensis, Streptorhynchus pelargonatus,
Stenoscisma humbletonensis and Spiriferellina crista fa;
KN1: Shales with layers of sandstone andconglomerate (500 m).
Most of the Member KN1 is poorly fossiliferous,
but fossils are rich at certain levels. The shale
containing Poikilosakos and other brachiopods,
bryozoans and trilobites is about 4 m in thickness, situated at 130 m below the base of theMember KN2 composed of a greenish-grey, finegrained sandstone with Monodiexodina matsubaishi.
The genus Poikilosakos was proposed by
Watson in 1917 with Poikilosakos petaloides
Watson from the Wayland Shale (Graham Formation) at Graham, Young County, north-central
Texas as type species. And the following seven

Introduction

The purpose of this paper is to indicate thepresence of a primitive and rare oldhaminoid
Po ikilosakos in the Middle Permian of Japan.
The specimens described here as Poikilosakos
kamiyassensis, sp. nov. were collected from adark grey shale in the lower part of the lower
Kanokura Formation (Member KN1; Monodiexodina kofuganensis Zone of Minato et al.,1978) at locality KF212 in the middle Matashirosawa Valley, a small tributary of the Shigejisawa Valley, Kamiyasse, Kesennuma City,
Miyagi Prefecture, northeastern Honshu (Figure 1).
In the Kamiyasse district the Kanokura Formation is about 1,100 m in thickness (Tazawa,
1973, 1976), and can be subdivided as follows
in descending order (Figure 2):
KN4: Shales with layers of sandstone andlimestone (320 m);
KN3: Massive limestones with layers ofconglomerate, sandstone and shale(130 m), containing Lepidolina multi-*

Received September 1, 198610

826. Poikilosakos from Japan11

II, 1 31' E=-==-::: .... :=':':':'.:;:
Yatsumoridairayam a

~ A

•

D.

B

§§ C

D. Kurosawa-yama

0:.»~:":'.~:;[23J

E
KAMIYASSE

~

".f>

-;

<l1

..

38' 53'N0I

kilometpr
1
I..... , ...

1==:::':::.:;'~
0.....J~Loc. KF212

KNl

r--- ......... :- :Figure 1.

.......

200 m

Map showing the fossil locality (KF212).

[

species of this genus are at present known fromthe Upper Carboniferous (Upper Pennsylvanian)
to the Middle Permian of the United States(Texas, Kansas), Soviet Union (Ural Mountains),
Indonesia (Timor) and Japan (Kitakami Mountains): P. petaloides Watson, 1917, P. tschernyschewi Fredericks, 1926, P. variabile Wannerand Sieverts, 1935, P. in/ormis Cooper and
Grant, 1974, P. sp. I Cooper and Grant, 1974,
p sp. 2 Cooper and Grant, 1974, and P kamiyassensis, Tazawa and Takaizumi, sp. nov. The morphology and classification of Poikilosakos havebeen discussed fully by Watson (1917), Dunbar
and Condra (1932), Williams (I953, 1965) andCooper and Grant (1974); and the life habit
has been reconstructed by Rudwick (I 971).
In the present study, the brachiopod specimens were collected by the junior author (Y.T.),and the systematics was prepared by the seniorauthor (J.T.). All the specimens are stored in
the Institute of Geology and Palaeontology,
Faculty of Science, Tohoku University, Sendai.

000000100oFigure 2. Columnar section of the Kanokura
Formation of the Kamiyasse district, showing thestratigraphic position of the fossil locality (KF212).
A: massive limestone; B: bedded impure limestone;
C: shale; D: sandstone; E: conglomerate. (Redrawn,
and adapted from Tazawa, 1973).

Systematic descriptions
Order Strophomenida Opik, 1934
Suborder Oldhaminidina Williams, 1953
Superfamily Lyttoniacea Waagen, 1883
Family Poikilosakidae Williams, 1953
Genus Poikilosakos Watson, 1917
Poikilosakos Watson, 1917, p. 212; Dunbar and Condra,
1932, p. 270; Williams, 1953, p. 287; 1965, p. H519;
Cooper and Grant, 1974, p. 389.

Type species:-Poikilosakos. petaloides Watson,
1917, from the Graham Formation of Graham,

12

lun-ichi TAZA WA and Yukihiro TAKAIZUMI

north-central Texas; Plattsmouth Limestone at
south of Williamsburg, Kansas; Neal Ranch
Formation of the Glass Mountains, west Texas(Watson, 1917; Dunbar and Condra, 1932;
Rudwick, 1971; Cooper and Grant, 1974).
Species other than type species assigned to
the genus:-Poikilosakos tschernyschewi Fredericks, 1926, from the Sakmarian Stage of Krasnoufimsk, central Ural Mountains, U.S.S.R.
(Fredericks, 1916, 1926).
Poikilosakos variabile Wanner and Sieverts,
1935, from the Middle Permian (= lower Punjabian, after Waterhouse, 1976) of Basleo,
western Timor (Wanner and Sieverts, 1935).
Poikilosakos inform is Cooper and Grant,
1974, from the Skinner Ranch Formation of
the Glass Mountains, west Texas; Bone Spring
Formation of the Sierra Diablo Mountains,
west Texas (Stehli, 1954; Cooper and Grant,
1974).
Poikilosakos sp. 1 Cooper and Grant, 1974,
from the Neal Ranch Formation of the Glass
Mountains, west Texas (Cooper and Grant,
1974).
Poikilosakos sp. 2 Cooper and Grant, 1974,
from the Word Formation of the Glass Mountains, west Texas (Cooper and Grant, 1974).
Poikilosakos kamiyassensis Tazawa and Takaizumi, sp. nov., from the lower Lower Kanokura
Forma tion (Mem ber KN 1) of Kamiyasse, southern
Kitakami Mountains, northeast Japan.
Diagnosis:-Small, simplest Poikilosakidae.
Pedicle valve nearly flat and completely attached.
Pedicle valve interior having about 2 pairs oflateral lobes and 1 pair of anterior lobes; bothof which irregularly developed and showing avery rough symmetry about median plane.
Remarks:-Poikilosakos is the simplest andmost primitive oldhaminoid, bearing a few

irregular, short and broad lobes in the latilobate
stage of Cooper and Grant (I 974), and asymmetric diductor muscles in the pedicle valve.
In the United States this genus has been recorded from the Upper Pennsylvanian to theMiddle Permian, but in Asia and Russia it occurs
from the Lower or Middle Permian. Poikilosakos
dzulfensis Sarytcheva, 1964, described fromthe Upper Permian (Dzulfian) of the Transcaucasus, U.S.S.R. may be the young of Leptodus Kayser, 1883 (Cooper and Grant, 1974,
p.390).
Pseudoleptodus Stehli, 1956 is distinguishedfrom Poikilosakos by its elongate, larger, conicalor sub conical shaped shell, and in having moreadvanced lobes, which regularly and symmetrically developed and strongly inclined towards
anterior.

Poikilosakos kamiyassensis, sp. nov.
Figure 3-la-7 cMaterial:-Eight, imperfect specimens, pedicle
valve internal moulds, collected by Takaizumi
from the lower part of the Lower Kanokura
Formation (Member KN1) at locality KF212 in
the middle Matashirosawa Valley, Kamiyasse,
southern Kitakami Mountains, northeast Japan,
IGPS coli. cat. nos. 99009-99016. Holotype:
IGPS coli. cat. no. 99010, illustrated in Figures
3-7a-c.
Diagnosis:- Large, transverse Poikilosakos;
pedicle valve interior with long, narrow, often
irregularly branched lobes.
Description:-Shelllarge in size for the genus.
Pedicle valve subcircular in young shells, becoming transversely wider in adult shells. Lengthof pedicle valve about 21 mm, width of pedicle
valve about 34 mm in the holotype; length of... Figure 3. Poikilosakos kamiyassensis Tazawa and Takaizumi, sp. nov., from the Middle Permian Kanokura
Formation (Member KNl) of Kamiyasse, southern Kitakami Mountains, northeast Japan. la-c. Internal mouldof pedicle valve and the rubber cast, IGPS coli. cat. no. 99009; la, b: mould (la xl, Ib x2); Ic: rubber cast(x2), 2. Internal mould of pedicle valve, IGPS colL cat. no. 99012 (xl), 3. Internal mould of pedicle valve,
IGPS coiL cat. no. 99015 (xl), 4a, b. Internal mould of pedicle valve, IGPS colI. cat. no. 99016 (4a xl, 4b x2),
Sa, b. Internal mould of pedicle valve, IGPS colL cat. no. 99011 (Sa x I, Sb x2), 6. Internal mould of pedicle
valve, IGPS colI. cat. no. 99013 (xl), 7a-c. Internal mould of pedicle valve and the rubber cast, IGPS colI. cat.
no. 99010 (Holotype); 7a, b: mould (7a xl, 7b x2); 7c: rubber cast (xl).

826.

Poikilosakos from Japan

13

la

1c

1b

2
3

5a

4a

4b

5b
6

7a

7c

14

fun-ichi TAZAWA and Yukihiro TAKAIZUMI

pedicle valve about 20 mm, width of pedicle
valve about 22 mm, width of hinge line 3.1 mm,
length of right diductor scar 2.2 mm in an immature but well-preserved specimen (IGPS coli.
cat. no. 99009).
Pedicle valve interior slightly concave tonearly flat, and the surface marked faintlywith fine pustules. Hinge line short and straight,
having a thick hinge ridge at posterior side.
Triangular areas (dental areas of Watson, 1917)
at just anterior to each side of hinge line whichis slightly concave and sculptured with finelongitudinal striae. Diductor scars asymmetricalabou t median plane; larger right one smooth,long, narrow, and sheathed on its sides entirely;
smaller one on left side, near posterolateral
margin of visceral region, more widely diverging
towards anterior than the right one. Visceralregion wholly enclosed by a thin wall, forming
in maximum two lateral lobes and one anterior
lobe on each side of valve. Lateral lobes slightly
inclined towards anterior. Both lateral andanterior lobes long, narrow, and often irregularly
branched. Interspaces between lobes very shallow
and broad. Median indentation strongly developed, reaching to about four-fifths valve
length.
External features of pedicle valve and bothinternal and external features of brachial valve
unknown.
Remarks:- The present materials are lacking
mould or cast of the pedicle valve ex terior andalso those of the internal and external partsof the brachial valve. However, the internal
structures of the pedicle valve are well preserved, especially in the specimen numbered
IGPS coli. cat. no. 99009, and they show thecharacters of the genus Poikilosakos.
Poikilosakos kamiyassensis, sp. nov. seems
to be an advanced form, and most resembles
P. tschernyschewi Fredericks, 1926 from theLower Permian (Sakmarian) of the central
Ural Mountains in its size and shape and inhaving long, narrow lobes. But in the Russain
species, the lobes are less frequently branched
and more symmetrically developed.
P. informis Cooper and Grant, 1974 fromthe Lower Permian (Wolfcampian and leonardian) of west Texas has long, narrow and irregularly branched lobes, and is regarded to bean evolved Poikilosakos species. The American
species is, however, more elongate in shell
outline, and the lobes are more irregular thanthe Kitakami species.
P. variabile Wanner and Sieverts, 1935 from
the Middle Permian exotic limestone block inBasleo, western Timor is much smaller in size,
and is clearly distinguished from the present
species.
The type species, P. peta!oides Watson, 1917
is the earliest and most primitive Poikilosakos,
and is easily distinguished from kamiyassensis
by its smaller dimensions and the massive lobes.
Acknowledgements
We are indebted to Prof. Koji Nakamuraof Hokkaido University and Prof. Yoshiyuki
Hasegawa of Niigata University for criticalreading of the manuscript, and Mr. Shohei
Otomo of Tohoku University for his help inphotography. To these people we offer ourthanks.
References
Cooper, G. A. and Grant, R. E. (1974): Permian brachiopods of west Texas, 2. Smithson. Cont. Paleo·bioi., no. 15, p. 233-793, pIs. 24-191.
Dunbar, C. O. and Condra, G. E. (1932): Brachiopodaof the Pennsylvanian System in Nebraska. Nebraska Coel. Surv., Ser. 2, Bull. 5, p. 1-377, pIs.
1-44.
Fredericks, G. (1916): The palaeontological notes, 2.
On some Upper Palaeozoic Brachipoda of Eurasia.
Mhn. Com. Ceoi., N. 5., !iv. 156, p. 1-87, pIs. 15 (in Russian).
--(1926): New Lyttoniinae from the Upper Carboniferous of Krasnoufimsk. Ann. Soc. Paleol1t.
Russie, tom. 6, p. 83-89.
Kayser, E. (1883): Obercarbonische Fauna von Lo-Ping.
In Richthofen, F. von, China, Bd. 4, p. 160-208,
pIs. 19-29, D. Reimer, Berlin.
Minato, M., Kato, M., Nakamura, K., Hasegawa, Y.,
Choi, D. R. and Tazawa, J. (1978): Biostratigraphy
and correlation of the Permian of Japan. Jour.
Fac. Sci, Hokkaido Univ., Ser. 4, vol. 18, nos.
1-2,p.II-47.

826. Poikilosakos from Japan
Opik, A. A. (1934): Obcr Klitamboniten. Tartu Unh'.
(Dorpat), Acta Comm., Ser. A, vol. 26, no. 3, p.
1-239, pis. 1-48.
Rudwick, M. J. S. (1971): The functional morphologyof the Pennsylvanian oldhaminoid brachiopod
Poikilosakos. Smithson. Cont. PaleobioL, no. 3,
p. 267 -282, pis. 1, 2.
Sarytcheva, T. G. (1964): Oldhaminid brachiopods
from the Permian of Transcaucasia. Paleont. Zh.
(1964), no. 3, p. 58-72, pis. 7, 8 (in Russian).
Stehli, F. G. (1954): Lower Leonardian Brachiopodaof the Sierra Diablo. Bull. A mer. Mus. Nat. Hist.,
vol. 105, art. 3, p. 262-358, pis. 17 -27.
--(1956): Notes on oldhaminid brachiopods. Jour.
Paleont., vol. 30, no. 2, p. 305-313, pis. 41, 42.
Tazawa, J. (1973): Geology of the Kaimiyasse area,
southern Kitakami Mountains. Jour. Ceol. Soc.
Japan, vol. 79, no. 10. p. 677-686 (in Japanese).
--(1976): The Permian of Kesennuma, Kitakami
Mountains: A preliminary report. Earth Science(Chikyu Kagaku), vol. 30, no. 3, p. 175-185, pis.
1-3.

Kamiyasse

J:Aiffi. Kesennuma

15

Waagen, W. (1883): Salt Range fossils, 1. Productus
Limestone fossils: Brachiopoda. Palaeont. Indica,Ser. 13, vol. 1, pt. 4, fasc. 2, p. 391-546, pis.
29-49.
Wanner, J. and Sieverts, H. (1935): Zur Kenntnis derperm is chen Brachiopoden von Timor, 1. Lyttoniidae und ihre biologische und stammesgeschichtliche Bedeutung. N. Jb. Miner. Col. Paliiont., Bd.
74, Abt. B, p. 201-281, pis. 6-9.
Watson, D. M. S. (1917): Poikilosakos, a remarkable
new genus of brachiopods from the upper CoalMeasures of Texas. Ceol. Mag., vol. 54, p. 212219, pI. 14.
Williams, A. (1953): The morphology and classificationof the oldhaminid brachiopods. Jour. Washi. Acad.
Sci, vol. 43, no. 9, p. 279-287.
--(1965): Oldhaminidina. In Moore, R. C. ed.,Treatise on Im'ertebrate Paleontology, Part H(Brachiopoda 1), p. H51O-H521, GeoL Soc.
Amer., New York and Univ. Kansas Press, Lawrence.

5<\fIllm. Matashirosawa

x.lIYflllil\. Shigejisawa

11:liMft.

)/t.:ftS2js:0"-":'It.-.L.*JiEIllii.lEUi Poikilosakos (:;tlt.-r'/, ~ -j-~§): rt4fm.:ftJ·.wJt!!.. ·1:j~W,St(fi1.J
9'ffli"-":'II".L.*ll"r1tIl-Hlli (K N 1 fflil!ll) o "i'iE'7;' .,. ft
I!l-r'/;t.:. f.L it l-I.::JiEH1~[jM(';'- ~ 'IlliiJEJIl Poiki losakos 7;(~g!.t** ~ iLt.:, .:. iL ~ Poikilosakos kamiyassensis i:: (,ilt L ~c!liJti"".o,2js:¥il;t**t~l''lj11~liWI1: <. :?Hil!:P-lfflil':: 1'1M."IH.:: 7H;!(i"" MHI:!'i:~ '~)',' (lobe) Nt"').:. i:: -C-lifiIJ£-11t ., it.o, jf;fl!llJ(n.:: l;t. r'J '7 It.-wJt!!.0rffli"-":'It.-.L. *7;'., ITc,1iJt ~ itt.: Poik il osakos tsche rnyschewi Fredericks, 1926 I.:: 1& b J: < fll,-C-B I). Poikilosakos 0~:7;'-C'IHt:'1i:«10jfl.iftLt.:H[-C­if,.o i:: ~ i. ., f.L.o,
IHil-{*,,~- . r~ii >R,$ii'i
iiimJ:Aifli~ift::ltiJl!XI1l.JJ'lllil-U'::-B~'l.

Trans Proc. Palaeont. Soc. Japan, N. S., No. 145, pp. 16-31,7 Figs., April 30, 1987.

827. NOTES ON FORBESICERAS (AMMONOIDEA) FROM HOKKAIDO(STUDIES OF CRETACEOUS AMMONITES FROM HOKKAIDO-LX)*
Tatsuro Matsumoto
c/o Department of Geology, Kyushu University 33, Fukuoka 812

Abstract. In this paper three species of the ammonite genus Forbesiceras which occurredin the Lower Cenomanian of Hokkaido are described and figured. They are F. largilliertianum(d'Orbigny), F. beaumontianum (d'Orbigny) and a new species. The last one is well defined on
the basis of at least eleven specimens from one and the same locality in Mikasa. It is allied toF. obtectum (Sharpe) and F. subobtectum (Stoliczka) but distinct in its own peculiar characters as described below.
Through this study a clioscaphitoid shape of the adult shell of Forbesiceras has become
distinct. The dimorphism which has been noticed by previous authors can be approved also
by examples in Japan, but my observation is yet insufficient to draw up the true feature.

is extended to another specimen obtained
from the Shumarinai area, northwestern Hokkaido, by Shunji Hayashi who transferred it
to the collection of Katsujo Yokoi in Kenbuchi.
In 1952 I studied preliminarily a specimen
which was obtained by Dr. Rinji Saito fromthe lower part of the Mikasa Formation andstored in Hokkaido University. This was listed
as Forbesiceras aff. obtectum (Sharpe) (Matsumoto, ed., 1954, p. 16) but is now missing
regrettably and excluded from the description
in this paper.
Before going further, I wish to thank sincerely
the above gentlemen for their generosity to letme study freely the valuable specimens in theircollections. Thanks are extended to Dr. Masayuki Noda and Mr. Seiichi Toshimitsu for theirkind help in taking photographs; also to Miss
Yoshimi Tanigawa for her assistance in preparing the typescript.
In the descriptions below, the following
letters are used for the dimensions. The measurements are in mm.
D=diameter, U=umbilicus, H=whorl-height, h=whorl-height at a point 180 0 earlier, B=whorlbreadth, R=radius, r=radius at a point 1800
earlier.

Introduction
Ammonites of the genus Forbesiceras sometimes occur in the Cenomanian sediments ofcertain facies in Hokkaido, but they have beenleft undescribed. One of the reasons for thedelayed situation was a difficulty in getting
a proper concept of the previously establishedspecies. This has been much relieved by the
recent work of Wright and Kennedy (1984)and I report in this paper the result of my study
with palaeontological descriptions.
The material for this study is mainly the
specimens which were obtained from the lower
part of the Mikasa Sandstone Formation exposed in the Ikushumbets Velley of central
Hokkaido. They belong to the collections ofTakemi Takahashi (TTC.), the Muramotos'(MC.) [Tatsuo and Kikuwo Muramoto], HajimeInoue and Yoshitaro Kawashita (YKC.), allin Mikasa; also those of Kenji Sanada and Yasujiro Kera in Sapporo; some other specimens
in the Geological Collections, Kyushu University(GK.) from the same formation in the Ikushumbets and adjacent Ashibetsu areas. My study*

Received July 18, 1986; read January 31, 1987
at Shizuoka University.

16

827.

Forbesiceras from Hokkaido

Palaeon to logical descriptions

Superfamily Acanthocerataceae de Grossouvre,
1894
Family Forbesiceratidae Wright 1952
Genus Forbesiceras Kossmat, 1898
Type species :-A I11mollites largilliertialls d 'Orbigny, 1841 (designated subsequently by Diener,
1925, p. 180).
Rel11arks:-The systematic position of Forbesiceras has been properly allocated by Casey(1965, p. 461) to the Acanthocerataceae as a
derivative from the Lyelliceratidae Spath, 1921,
through Neophlycticeras Spath, 1922 (a memberof the Lyelliceratidae) and then Paradolphia
Casey, 1965 (an ancestral member of the Forbesicera tidae).
The diagnosis of this peculiar genus has been
given concisely and adequately by Wright and
Kennedy (1984, p. 89). They have noted thata species of Forbesiceras is markedly dimorphic
in size, but they have not mentioned about
the length of the body-chamber and the outlineof the apertural margin.
Through this study, I have noticed in someexamples of at least two species that the bodychamber is approximately about 180 0 in length,that its expansion ratio of whorl-height decreases in the last stage where the umbilical seamegresses markedly and that the adult shell shows
accordingly a clioscaphitoid outline.
In connexion with the above features, I
have endeavoured to find evidence for the
dimorphism. The difference in size between
the presumed microconch and macroconch
may be great in some species (e.g., F largilliertianum) but does not seem to be so great
in some others (e.g., a new species described
below). In comparison with the microconch,the macroconch seems to have a broader whorlwith somewhat more convex flanks in theadul t stage.
In view of some tendency to the differentiation of the ornaments between the inner andouter parts of flank, I expected at first such amarkedly dimorphic difference in the apertural

17

margin as that observed in some ammonitesof the Oppeliidae, but this does not seem tooccur in Forbesiceras. So far as I have examined,
the apertural margin is simple, showing only
an ocular sinus, even in the case of the presumed
microconch. Anyhow, I confess that the observation about the dimorphism in Forbesiceras is
yet insufficient.
The genus Forbesiceras is geographicallywidespread. Its occurrence has been recorded
from Europe, central Asia, the Middle East,
north, south and west Africa, Madagascar,southern India, Texas, California and Japan(Hokkaido and Shikoku). The genus ranges
almost throughout the Cenomanian stage, but
the stratigraphic range of a species is shorter.
According to Wright and Kennedy (1984),
for instance, F beaW1l0lltial111m is widespreadin the Lower Cenomanian, although it does
not occur abundantly; F largilliertianum isalso widespread in the Lower Cenomanian
but in England it occurs also in the Zone ofAcanthoceras jukesbrowllei of Middle Cenomanian; F obtectum is well recorded from theMiddle Cenomanian of various regions but
may appear earlier: F bicarinatum Szasz, 1976
is so from the Upper Cenomanian Zone of
Calycoceras guerangeri and ranges into theZone of Metoicoceras geslinianum.
Forbesiceras largilliertianum (d'Orbigny)
Figures 2-1a-d1841. Ammonites Largilliertianus d'Orbigny, p. 320,
pI. 95.
1864. Ammonites Largilliertianus d'Orbigny; Stoliczka,
p. 94, pI. 49, fig. 1.
1898.
Forbesiceras Largilliertianum (d'Orbigny);
Kossmat, p. 125.
1964. Forbesiceras largillierti Cd'Orbigny); Collingnon,
p. 19, pI. 321, fig. 1409.
1984. Forbesiceras largilliertianulll (d'Orbigny); Wrightand Kennedy, p. 89 (with full list of synonymy),
pI. 11, figs. 2-6; pI. 12, figs. 1-3,9; pI. 16. fig. 2;
text-figs. 12A-L; 13A-Z; 14A-H.

Material:-A single specimen, TTC. 510704(T. Takahashi ColI.) from loc. Ik 8800p. Its
replicas are in the Museum of Mikasa and also

18

Tatsuro MATSUMOTO

in the Geological Collections, Kyushu University.
Description:-The phragmocone ends at about
the diameter of 63 mm and the body-chamberis preserved for about a half whorl. The preserved
end is probably the original apertural margin.
The spiral outline is changed at about 90° after
the last septum, so as to lower the ratio of whorlheight expansion and to let the umbilical seamegress nearly straight forward and then slightly
incurved, resulting in a clioscaphitoid shape.
Keeping pace with this, the highly compressedshape of the whorl, with B/H=0.44, is somewhat relieved and the adoral half of the bodychamber has gently convex flanks, with B/H=
0.57, and a broadly rounded venter on which
the median raised line and ventrolateral keels
weaken and then disappear.
The body-chamber looks almost smoothon the internal mould of its posterior part but
has numerous, dense, fine subcostae and lirae on
the outer flanks and venter of the rest main part.
On the inner flank there are several radial elevations disposed at wide intervals. They are somewhat bullate around the umbilicus and extend
but weaken outward to the middle of flank.
The numerous fine subcostae on the outer flankare gently concave or somewhat prorsiradiate.
Some of them are extended from the inner ribs
showing a gentle flexuosity. They cross theventer transversely. The apertural margin isparallel to the simple line of the subcostae as
mentioned above and has an ocular sinus.
The visible part of the phragmocone is quite
involute, much higher than broad, subtrapezoid
in section and broadest below the mid-flank,with a narrow and nearly flat venter demarcatedby ventrolateral keels. The ribs on the outerflank are narrow and somewhat prorsiradiate.
They are more distinct, less crowded and lessnumerous (15 or 16) in the preceding quarter
than those in the last quarter of the septate
whorl. The ribs form small, clavate tubercles
at the ventrolateral keel and then pass acrossthe venter with weakening. A faintly serrated,
low keel-like elevation is partly discernible along
the siphonal line. There are widely spaced sub-radial ribs on the inner flank, showing a gentle
sinuosity together with some outer ribs on
their extension. Partly exposed sutures arethose of Forbesiceras pattern.
Measuren7ents:D

U

H

B

B/H

h

H/h

40.4
23.0
(1) 90.0(.45)(.26) 0.57 39.1 1.03
1.6
47.2
21.0
(2) 77.2 (.02)(.61)(.27) 0.44 29.5 1.60
39.1
17.0
(3) 63.3(.62)(.27) 0.43 23.7 1.65
(1): preserved end, (2): 90 0 earlier than (1), (3): at thelast septum, i. e. about 180 0 earlier than (1).

COn7parison and discussion:-Based on theabove described characters, this specimen is
identified with F largilliertianun7 (d'Orbigny),which has been described amply by Wrightand Kennedy (1984). It is certainly an exampleof microconch, because of its small size (D=63mm at the end of phragmocone) and reduced
ornament of the body-chamber. It is, however,somewhat different from the illustrated British
example of an adult microconch (Wright and
Kennedy, 1984, pI. 12, fig. 9) in that it hasdense and fine outer lirae or subcostae andwidely spaced and blunt inner ribs on the mainpart of the body-chamber instead of more
distinct reduction of the ornament. This may
be due to the state of preservation and also avariation within a species. The clioscaphitoid
shape of the body-chamber, with an egressedumbilical seam at the last stage, has not beenrecognized in the incomplete specimens from
Europe.
A fragmentary specimen from the Lower
Cenomanian sandstone of the Monobe area
(Shikoku), which I called Forbesiceras (?) sp.
aff. F beaun7ontianun7 (d'Orbigny) (Matsumoto,
1982, p. 35, pI. 4, fig. 3), is not a named species
because of almost closed, very narrow umbilicus. It may be better compared with an immature shell of F largilliertianum in which ribs
are not so fine as those of the mature one. It
was obtained by T. Kozai together with Turrilites(Mesoturrilites) aff. T. (M) aumalensis Coquand
and Ostringoceras cf. 0. bechii (Sharpe).

827. Furbesiceras from Hokkaido

19

Occurrence:- The described single specimen
was obtained by T. Takahashi from a nodule
at loco Ik 8800p, derived from the lower partof the Mikasa Sandstone Formation exposed ina stream called the Hachi-no-sawa, Migi-futamata(recently called the Ganseki-zawa by somepeople), in the upper reaches of the Kami-ichino-sawa, a tributary of the River Ikushumbets,
Mikasa district of central Hokkaido.
Forbesiceras beaumontianunz (d'Orbigny)
Figures 2-2a-d1841. Ammonites Beaumontianus d'Orbigny, p. 328,
pl. 98, figs. 1, 2.
1964. Forbesiceras largillierti (d'Orbigny); Collignon,
p. 60, pI. 334, fig. 1499 only.
1965. Forbesiceras beaumontianum (d'Orbigny); Casey,p. 460, fig. 173.
1984. Forbesiceras beaumontianum (d'Orbigny); Wrightand Kennedy, p. 91, pI. 12, figs. 7, 8; pI. 13, fig. 1;
text-figs. 15A-C; 16A-F (with full list of synonymy).

Material:-A single specimen, H 28 in K.
Yokoi Collection (Kenbuchi). As it is partly
damaged, it is carefully embedded in a plateof gypsum. Its younger part is removable.
Description:- The last septum is at D=80 mm
and only the posterior portion of the bodychamber is preserved. The trace of the umbilicalseam suggests that the body-chamber may
have exceeded 200 0 and accordingly the entire
shell diameter may have been 150 mm or more.
The umbilicus is open narrowly (about 7%of D) in the phragmocone and enlarged in thebody-chamber upto 23 mm (probably over 10%of D) at the last stage. The expansion ratio of
whorl is high (1.7 or 1.8 111 a half whorl). As
the right side of the outer whorl is not wellpreserved, the ratio B/H cannot be precisely
measured, but it must be small. In younger
stages the flank becomes flat and the venter isnarrow and flat, being demarcated by ventrolateral shoulders. Later the flank is gently convex
and the venter seems to widen.
Numerous fine ribs on the outer flank areslightly prorsiradiate and gently curved forward.
They form small tubercles at the ventrolateral

A
B
Figure 1. Forbesiceras mikasaense sp. nov.
Outline of the holotype in cross-section. A: the lastquarter of the body-chamber; B: along the maximum
diameter through the middle of the body-chamber.
(T. M. delin.)
Scale-bar: 10 mm.

shoulder, crossing the venter vertically. The ribdensity increases gradually as the shell grows.
For example, there are 15 outer ribs in a quarter
whorl at D=35 mm, 20 at D=43 mm and 34 at
D=90 mm. The ventrolateral tubercles are shortly
clavate in earlier stages but minutely nodate

20

Tatsuro MATSUMOTO

1b1c

82 Z Forbesiceras from Hokkaido
later.
The inner ribs around the umbilicus are lessnumerous, more distant and coarser than theouter ones. Some of them are extended to or
branched into outer ribs, showing a gentle
sinuosity, but the extension is not so clearlytraced in some others.
This specimen is covered by an inner shelllayer for the most part. The sutures are observable through a semi-transparent shelly substance. Their pattern is similar to an example
illustrated by Casey (1965, fig. 173c), showing
an adventitious lobe in the saddle between E
and L.
Measurements:-oU
H
B
B/H R/r(1) 85.5 5.9 (.07) 51.2 (.60)
1.8(2) 43.5 3.0 (.07) 26.5 (.61) 10.6 (.24) 0.40 1.7(1): 30 0 ahead of LS (last septum), (2): 180 0 prior toLS.
Comparison and discussion:-On the groundof the above described characters this specimen is undoubtedly identified with F. beaumontianum (d'Orbigny), which has recently beenredescribed by Wright and Kennedy (1984).
It resembles especially the one from the Lower
Cenomanian Mantelliceras mantelli Zone, andNeostringoceras carcitanense Subzone of southern England, illustrated by them (ditto, pI. 13,
fig. 1). The two specimens are nearly of similar
size and have similar ornamentation, but theformer has the last suture at D=80 mm, whereas
the latter with diameter of at least 90 mm iswholly septate. The authors did not indicate
clearly the criteria to distinguish a micro conchfrom a macroconch of this species. It is difficult
to determine whether the described specimen
from Hokkaido should be regarded as a microconch or a smaller example of macroconch.
Occurrence:-The described specimen (H25)21

was found in a nodule scattered as a boulder in
the Sanju-sen-zawa, a branch stream of the River
Shumarinai, Uryu-gun, northwestern Hokkaido,
by Shunichi Hayashi who affiliated it kindly to
K. Yokoi's Collection. Several species of ammonites which suggest the early Cenomanian
age were obtained from the same stream (seeMatsumoto and Inoma, 1975).
Forbesiceras mikasaense sp. nov.
Figures I, 3-la-c, 4-la-c. 5-la-2b. 6-la-5

Material:-(1) Holotype, TTC. 390413 (Figures 3-1a-c; Figure 1), from loco Ik 1100.
Paratypes (2) Me. Ik 1101-c (Figures 4-1a-c)and (3) H. Inoue's specimen (on display atMikasa Museum), both adult shells like (1); TTe.
410626 (Figures 5-1a-b), (5) TTC. 400728(Figures 6-3a-c), (6) TTC. 410710 (Figures
6-4a-c), (7) GK. H 8108 (Figure 6-5) (collectedby T. Muramoto and me), (8) TTC. 400426(Figures 6-2a-c) and (9) TTC. 390412 (Figures
6-1a-c) which are gradually smaller and represent earlier growth-stages; also (10) Y. Kera's No.
129 (Figures 7-2a-b) and (11) K. Sanada's(Figures 7-la-c) and (12) GK. H8125 [=TTe.
400523] ; all from loco Ik 1100-Ik 1101. Fiveother comparable specimens, (13) TTC. 370805(Figures 5-2a-b) from Torii-zawa, (14) YKe.
470501, (15) GK. H 5424 from loco Ik 1054,(16) GK. H 8109 from the Kami-ichi-no-sawa(boulder) obtained by a student of Mikasa
High School, and (17) GK. H 8110 collected by
Keisaku Tanaka from loco p. 65 in the Porokoashibetsu.
Diagnosis:-Adult shell similar to F. obtectum(Sharpe) and F. subobtectum (Stoliczka) in
having the ribs which bend strongly backward
on the outer flank but such ribs appear later
and are lower and broader. Immature shell

f- Figure 2. I-a-d. Forbesiceras largilliertianum (d'Orbigny)
TIC. 510704, from lac. Ik 8800p, Mikasa area; lateral (1a), frontal (I b) and ventral (lc, Id) views, xl. Venter isshown successively by Ib, Id and Ic, with some overlap.
2a-d. Forbesiceras beaumontianum (d'Orbigny)
H 28 of K. Yokoi CoIL, from the Shumarinai area; lateral (2a) and ventral (2b) views of outer whorl, x I; lateral(2c) and frontal (2d) views of inner whorl, with some overlap with (2a), x 1.2
Photos (Figures 1-6), without whitening, by courtesy of Dr. M. Noda. Arrow: position of the last suture.

22

Tatsuro MA TS UMO TOu

Figure 3. Forbesiceras mikasaense sp. nov.
Holotype, TIC. 390413, from la c. lk 1100, Mikasa area ; lateral (la), fro ntal (lb) and ventral (I c) views, x O.77.
1c shows the venter of the last two thirds of the body-chamber.

827. Forbesiceras from Hokkaido
similar to that of F chevillei (Pictet et Roux).
Description:-Adult shell fairly large, normally about 180 to 200 mm in diameter. Bodychamber about 180 0 in length, broader thanphragmocone with more convex flanks and wider
venter. In its last part the expansion ratio of
whorl-height decreased and the umbilical seamegressing nearly straight forward, resulting ina clioscaphitoid shell-form; the growth-lines
on the last part remarkably concave on the
inner flank, suggesting ocular sinus, and curved
gradually to be rectiradiate on the outer flank,
without ventral projection or sinus.
Main part of the body-chamber and thepreceding last part of the phragmocone ornamented with blunt (low and weak) ribs, which
are gently concave on the inner flank, bent
strongly at about the mid-flank, rursiradiate
and convex on the outer flank; also train of
tubercles at the ventrolateral shoulders and amedian ventral keel sometimes with weak serrations. These ventral ornaments weaken as theshell growth and disappear on the last part
where the venter is flatter and wider than thatof the preceding main part and the ventrolateralshoulders are subrounded (Figure 1).
In the preceding, late middle growth-stage,
the whorl is quite involute, showing high ratioof whorl-height expansion, and much higher
than broad, with very gently convex flanks,
maximum breadth at about mid-flank andnarrow venter. Several ribs at wide intervals
on the inner flank, narrow, somewhat prorsiradiate and gently concave, ending at or disappearing before reaching the mid-lateral tubercles,
which are somewhat bullate but later morerounded but weaker. Ribs on the outer flankat this stage slightly prorsiradia te to nearlyrectiradiate and fairly broad, with gentle slope
to the anterior, but steeply inclined backward.
Two to three outer ribs correspond to each
mid-lateral tubercle, with branching or intercalation. At the end of this stage, i. e. for a shortwhile passing to the late stage described above,
the outer ribs consist of mixed radial and somewhat rursiradiate ones, the latter of whichsoon become predominant, whereas the mid-23

lateral tubercles become indistinct. The outerribs form clavate tubercles at the ventrolateralshoulder and numerous rib lets, 3 to 5 for eachclavus, pass transversely across the venter, wherea weak keel-like elevation runs along the siphonalline.
In the early middle growth-stage, from theshell diameter of about 20 mm up to 60 mm
or so in some examples, the shell-form similar
to that described above, the outer ribs generally
more numerous, narrower and curved more
distinctly forward than in the late stage, though
there may be individual variation in density
and coarseness; the mid-lateral tubercles also
numerous, forming a spiral train in some examples (e.g., TTC. 400426), more or less bullate,generally showing one by one correspondance
to the outer ribs but for occasional intercalationor bifurcation of the ribs; the ribs on the innerflank narrow, occurring at wide intervals, gently
concave and somewhat prorsiradiate, forming
a sinuosity or even somewhat falcoid form
together with some of the outer ribs on theirextension; the ventrolateral tubercles pointed
to shortly clavate according to the breadth ofthe outer ribs; ventral ribs weak and single,
running transversely across the narrow venter
between the ventrolateral tubercles; may be
doubled in the passage substage to the latestage of multiple riblets. The median elevationon the siphonal line absent in earlier substage
and discernible very weakly later.
In the early stage of still smaller size, thewhorl is compressed, with smooth and flat
main part of the flank; short outer ribs strongly
prorsiradiate, forming minute tubercles at theedges of narrow venter. Still earlier, below
5 mm or so in diameter, the shell is smoothand the ventrolateral shoulder subrounded.
Remarks:- There is some extent of variationin this species. As the specimens were obtained
from one and the same bed in a small quarry
and they have essentially the same charactersin common, I regard them as belonging to one
and the same species, even if there is some difference in minor points.
The most remarkable aspect of variation may

24

Tatsuro MA TSUMOTOu+

Figure 4. Forbesiceras mikasaense sp. nov.
Paratype, Me. 1l01-C, from loco lk 1101 , Mikasa area; lateral CIa), frontal (Ib) and ventral (I c) views, x ca 0.7.

827. Forbesiceras from Hokkaido
be concerned with the ornament. For example,
a fine specimen (Figures 7-1a-c) in K. Sanada's
Collection has unusually finer and weaker ornaments than those in others of the corresponding
size, i. e. phragmocone of the middle growthstage. Its inner ribs are very weak but occur atwide intervals and similarly subradial; its midlateral tubercles are extremely bullate anddelicate, each of which corresponds to 3 or 4
outer ribs already at such an early stage of small
diameter where one by one correspondence isnormal in others; also the tubercles become
obsolete in an earlier stage than in others; theouter ribs are also more numerous and weaker,
although they broaden gradually as the shell
grows. Its shell-form is comparatively morecompressed than that of others. Although themain part of its body-chamber is unpreserved,
the specimen is comparable with No. 129 of
Kera's Collection, which may represent a microconch (see discussion below).
On the other hand, TTC. 400426 (Figures
6-2a-c), the 8th specimen, has coarser ribs,
coarser and more rounded lateral tubercles andcomparatively broader whorl than the normal
ones.

Comparison and discussion:- This species canbe grouped with F. obtectum (Sharpe, 1853)(see Wright and Kennedy, 1984, p. 94) and F.
subobtectum (Stoliczka, 1864) (ditto, p. 95)
in that the ribs swing back remarkably in thelate growth-stage. In these two species thisfeature is shown already in the septate whorl
and continues for a considerably long period
in which the mid-lateral tubercles are distinctly
developed at the bending point of the ribs,
whereas in our species the bending is muchdelayed to appear at the last stage of thephragmocone and characterizes the main partof the adult body-chamber; also the mid-lateral
tubercles weaken when the bending begins
and are scarsely discernible or almost obsolete
and the ribs are also blunt in the stage of bending. In general the ribs are narrower but more
distinct in F. obtectum and coarser and muchstronger in F. subobtectum than those of F.
mikasaense. Moreover, the adult whorl is typically broader in this species than that in F. obtectum and narrower than in F. subobtectum,
although there is some extent of variation withrespect to the whorl-breadth.
We should now consider the dimorphism inA1easurements:B
H/h
H
B/H
Specimen
D
U
-43
-0.49
-88
near end
1.54
49.4 (.28)
0.47
105.0 (.59)
5.0 (.03)
100° from LS
179.0
0.43
37.5 (.27)
1.87
87.8 (.64)
137.0
at LS
-0.45
-53 (.27)
118.0 (.60)
7.0 (.04)(2) near end
197.5
-0.47
-44 (.30)
1.87
92.5 (.63)
6.0 (.04)
148.0
near LS
51.0 (.28)
0.47
1.47
109.0 (.59)184.0(3) 90° from LS-149.0atLS
29.5 (.27)
0.40
2.05
73.8 (.67)(4) near LS
110.0
-1.78
0.46
26.0 (.29)
1.0 (.01)
57.0 (.63)(5) near end
90.0
17.8 (.27)
0.42
1.85
42.7 (.64)67.0(6) near end
0.44
1.78
16.5 (.28)
37.4 (.62)-60.0(7) near end
10.0 (.30)
0.47
1.74
21.4 (.63)
33.8(8) near end
2.8 (.27)
0.44
1.54
6.3 (.60)
10.5(9) near end
28.0 (.25)
0.39
1.89
72.0 (.65)
110.0(10) at LS
24.5 (.25)
0.38
1.83
64.0 (.64)
1.2 (.01)
100.0(11) at LS
0.4415.4 (.28)
1.67
35.0 (.63)56.0(12) _60° from end
0.41
29.0
71.0
(13) near end
0.38
22.0
_90°
58.0
0.34
1.89
34.5 (.22)
102.0 (.65)
158.0(14) 90° from LS
1.82
26.5 (.21)
0.33
80.0 (.64)
1.0 (.01)
125.0
at LS
Specimens (1)-(14): see Material; end: preserved end; LS=Last suture; -: approximate because of restoration.

(1)

25

26

Tatsuro MA TSUMOTO

...

827.

Forbesicerasfrom Hokkaido

this species. If I compare F mikasaellse with
F obtectum, its holotype and the first twoparatypes with D= 180- 200 mm could be regarded as macroconchs. They show a comparatively larger ratio of B/H and the bodychamber
has fairly convex flanks. I have not yet seen asmaller example in our material which would
be comparable in size with such British specimens as figured by Wright and Kennedy (l984,
pI. 14, figs. 1, 2) in which ribs begin to swing
back at whorlheight of about 40 mm. According to them (ditto, p. 95), a microconch has
an estimated diameter of 130 mm. This may benearly comparable with the 10th specimen, i e.
no. 129 of Y. Kera's Collection, an adult shell
which shows an egressing umbilical seam at thelast part, with maximum diameter of about 135
mm (deficient portion restored). It is 110 mm indiameter at the end of the phragmocone andsomewhat more compressed (B/H=0.39) thanothers. The 4th specimen, TTC. 410626, with
D=110 mm at LS and B/H=OAO, and also thelIth, with D=100 mm and B/H=0.38 at LS,
may be comparable with the 10th specimen,
although the main part of the body-chamber is
not preserved in these two specimens. I would
state that these three examples could possibly be
regarded as micro conches of F mikasaense.
Should this be the case, the difference between
the microconch and macroconch would be by
no means great, if not absent, in this species.
Up to the middle growth-stage there is no
significant distinction between this species andF chevillei (Pictet et Renevier, 1866), which
has been redefined by Wright and Kennedy(1984, p. 93). When I treated smaller, incomplete septate shells alone, I thought that they
could be identified with F nodosum Crick,1907 or F. sculptum Crick, 1907, based on my
examination of the Crick's types from South
Africa at the British Museum (N. H.). Wright and~27

Kennedy (l984) have regarded the two species
named by Crick as synonyms of F chevillei andshown, on the basis of the British material, that
F chevillei has no ribs of F obtectum type but
becomes smooth in the late growth-stage (ditto,p. 94, pI. 13, fig. 2; text-fig. 17). The smaller,
incomplete specimens from Mikasa are now
well connected with larger adult specimens
obtained from the same bed. They are all examples at various growth-stages of one and thesame species. Unless the adult specimen of
F mikasaellse be found from the type localityof F chevillei in Switzerland, I shold rely on
Wright and Kennedy's observation and conclude
that F mikasaense is a well defined new species.
Occurrence: - The holotype and the para types(2) to (11) occurred in a bed of sandstone
at loco Ik. 1100-Ik 1101, Katsurazawa quarry,
Mikasa, on the right (northern) side of the River
Ikushumbets. The bed belongs to the Zone ofMantelliceras japonicum and is early Cenomanian(see Matsumoto et al., 1969, p. 287; Matsumoto,1975, p. 157). Five other specimens were obtained at nearby localities in the same zone
or in the presumable extension of the same ~one.
The occurrence of at least 11 specimens
in the same bed at the same locality (a small
quarry) may imply that the species was not
rare. Since the quarry was abandoned and a
new road was constructed, it has become difficult to collect fossils from this locality. Itshould be also noted that even when the quarry
was in operation, the 11 specimens including
4 adult ones, were obtained by five friends ofmine at different times through their laborious
hunting. On the other hand, more examples ofthis species may have been obtained by otherpersons with whom I have no acquaintance.
These situations suggest that it is difficult toestimate precisely to frequency of occurrence.

Figure 5. Forbesiceras mikasaellse sp. nov.
la-b. Paratype, TTC. 410626, from loco lk 1100, Mikasa area; lateral (1a) and ventral (1 b) views, x ca 0.9.
2a-b. Forbesiceras cf. F. mikasaense sp. nov.
TIC. 370805, from the Torii-zawa, Mikasa area; lateral (2a) and ventral (2b) views, xl.
The two specimens show a passage from the chevillei-nodosum type middle growth-stage to the mikasaense
type late stage, although the earlier whorls are badly crushed and dislocated in TTC. 370805.

Tatsuro MATS UMOTO
28

827. Forbesiceras from Hokkaido
References cited
Casey, R. (1965): A monograph of the Ammonoidea of
the Lower Greensand. Part VI. Monogr. Palaeontogr. Soc., 1964, p. 399-546, pIs. 67-90.
Collignon, M. (1964): A tlas des fossiles caracteristiquesde Madagascar (Ammonites), fasc. 11 (Ci~nomani­en). 152 pp., pIs. 318-375. Service Geol., Tananarive.
Crick, G. C. (1970): Cretaceous fossils of Natal. In
Anderson, W., Third and final report of the Ceological Survey of Natal and Zulu land, p. 161250, pIs. 10-15, London.
Diener, C. (1925): Ammonoidea neocretacea. Fossiliulll
Catal. (1: Animalia), vol. 29, 244 pp.
Kossmat, F. (1895-1898): Untersuchungen tiber die
Siidindische Kreideformation. Beitr. Paliiont. Ceol.
Ost.-Ung., vol. 9 (1895), p. 97-203 (1-107),
pIs. 15-25 (1-11); vol. 11 (1897), p. 1-46
(108-153), pIs. 1-8 (12-19); vol. 11 (l898),
p. 89-152 (154-217), pIs. 14-19 (20-25).
Matsumoto, T. (ed.) (1954): The Cretaceous System in
the Japanese Islands, 324 pp., 36 pIs., Japan Assoc.
Prom. Sci. Res., Tokyo.
--(1975): Additional acanthoceratids from Hokkaido. Mem. Fac. Sci, Kyushu Univ., (D), Ceol,
vol. 22, no. 2, p. 99-163, pIs. 11-23.
- - (1982): Upper Cretaceous ammonites from theMonobe area, Shikoku. In Matsumoto, T. andTashiro, M. (eds.): Multidisciplinary researchin the Upper Cretaceous of the Monobe area,
Shikoku. Palaeont. Soc. Japan, Spec. Pap., no. 25,29

p. 31-52, pIs. 1-7.
--and Inoma, A. (1975): Mid-Cretaceous ammonites
from the Shumarinai-Soeushinai area, Hokkaido.
Mem. Fac. Sci., Kyushu Univ., (D), Ceol., vol. 23,
no. 2, p. 263-293, pIs. 38-42.
- - , Muramoto, T. and Takahashi, T. (1969): Selected
acanthoceratids from Hokkaido. Ibid., vol. 19, no.
2, p. 251-296, pIs. 25 -38.
Orbigny, A. d'. (1840-1842): Paleontologie fran~aise;
Terrains Cretaces. vol. I, Ci~phalopodes, p. 1-120(1840); 121-430 (1841); 431-662 (1842); pIs.
I-lSI, Paris.
Pictet, F. J. and Renevier, E. (1866): Notices geologiques et paIeontologiques sur Ie Alpes Vaudoises
et les regions environnantes. IV. Cephalopodes deCheville. Blill. Soc. Valldoise Sci. Nat., vol. 9, p.
93-114, pIs. 3-5.
Stoliczka, F. (1863-1866): The fossil Cephalopoda of
the Cretaceous rocks of southern India: Ammonoidea, with revision of the Nautilidae. Mem.
Ceol. SlIYV. India, Palaeollt. Indica, vol. 3, p.
41-65, pIs. 26-31 (1863); p. 57-106, pIs. 32-54(1864); p. 107-154, pIs. 55-80 (1865); p. 155216,plL 81-94(1866~
Szasz, L. (1976): Nouvelles especes d'ammonites dansIe Cenomanien de la region de Hateg (Carpates
meridionaIes). Dari de seama ale sedintelor, vol.
62, p.169-174, pIs. 1-4.
Wright, C. W. and Kennedy, W. J. (1984): The Ammonoidea of the Lower Chalk. Part I. Monogr.
Palaeontogr. Soc. London, p. 1-126, pIs. 1-40
(Publ. No. 567, part of vol. 137 for 1983).

Ashibetsu fo'~U, Ganseki-zawa '615iR., Hachi-no-sawa Ji.(7)if(, Ikushumbets ~~7]U, Kamiichi-no-sawa l:.-(7)iR, Katsura-zawa t~iR, Kenbuchi oriUiJlll, Mikasa .::.~, Poroko-ashibetsu~1>Frjl1i~U, Sanju-sen-zawa .::. -/-fJi!iR, Sapporo *L~lt Shumarinai *~i1'J.

... Figure 6. Forbesiceras mikasaense sp. nov.
Paratypes showing early to middle growth-stages, all from loco Ik 1100-ilk 1101, Mikasa area.
1. TTC. 390412; lateral (1a), frontal (1b) and ventral (lc) views, x ca 3.5. 2. TTC. 400426; lateral (2a), ventral(2b) and frontal (2c) views, x ca l.6. 3. TIC. 400728, lateral (3a), ventral (3b) and frontal (3c) views, xl.
4. TIC. 410710; lateral (4a) view, xO.9; ventral (4b) and frontal (4c) views, xl. 5. GK. H 8108, collected by
T. Muramoto and T. Matsumoto; lateral view, xl.l.

Tatsuro MATS UMOTO
30

827. Forbesiceras from Hokkaido

31~tifJ):ii\tRE?Mi:n~J( Forbesiceras I':~,'-C: B4:!pG i, Forbesiceras liRET6;Q" SJni'd:~jJ; ~ Woj ~e!t;Q''d:;Q' '? t,: t~ n, ihj:7j.(7)Cj!:~iJ· G7i!1v C"~tJi\ ~ h -C" t~, ~[illi'!limJR;~ ("He C (7)holotype ;!tV"I=Ml,,< (7)JJX:tfJtll(7)i,(7)1:: A)· H2fs:%7..ut . j:j: J: Ii· J!l.:EB~* . fWNEltia . JllrEB*al\~ (tJ,J: C), ;!tV"I= t*f~- . ~j:j:ilil),j( (B) (7):;tR;Q''/i'i'L' L -C tR~ . ~Jf; Lt~ N "'~2fs: H£
f1liL-Cr~'?t~(7)-C", -=hHJfjEL, ;j;:(7)3fif[~fa'(ljIjL, <'lei!!':' ~jJ;Lt~, .fhli A. F.largillie rt ianum (d'Orbigny) (~'tf:ljlj III iJittJl,t~j!{i'Ji'5)jrli~RE), B. F. beaumont ianum (d'Orbig-ny) (*If4JI*J:t1Jl.tJI,t), C. F. mikasaense sp. nov. (~j!Ii<j,''5)jrli~, Mantelliceras japonicum'ffi':-1: /7-=.7 /I>}\'rlif,) -C"if:, 6, Alil fli;Jf*t'::';Q', f;:j!;1f;Q{J: < ~ ;> O:J:-- ;>(7)JJX:AA~ ; B I;l:fW'd:RE

I±l t: ;Q{JIfl.~B1 'd:JfYIlj' ~ jJ;T ; C lit& i, J-. <, 9'lf.JtIl i -C"li F. chev i II e i ( Pi c te t et Roux) 1= ~J(
ft:J.T6iJ" JJX:~!\JtIl(7)~li.f(7)fill(7)J: oj 1=:iJZiilf-C"7J.· <, mIJllii9'f.'l1.'{"f&1iI=IlEfl!lT6""-(7),¥=~(7)Jl1J;Q'
3VJtT6*fjl&~7f.T, -=(7)Ml(7)!ffillllmJli, F.obtectum(Sharpe) 1= if:, 6 i,iJ', .fhJ: I) I±lJJtJtll;Q'i!! <, Ip];\!Z";Q'~4i" ; F. subobteclun (Stoliczka) (7)±i!Jil-(7)J: oj l=tJl. <gt < 7J."', A I:: C I=~,'-Cli, JJX:~!\~(7)f£m;Q'*~~ (7)tf~ '{", Clioscaphiles ~(7)*,iM(7)w,:ft~jJ;T-= I:: ; ~D*,*li~
Ii lUXS1Jil.*4i -c"if:, 6 -= I:: 'd: 1::", ftE*(7)ifJ):7j.(7)j'f# '{"Ii J: < V;Q' '? -C" 7J.·iJ· '? t:. ::.. I::;Q" ~ [ill (7) i,(7)-C",¥IJUJl Lt~, -=(7)~ffir)('iJil.fl:l= Lt:';Q', J:lie:;tR(7).:."H~I= J: 6piT;Q'~ vn-C*~ <, i*"l;ji~I:: • • (7)~~i,'?-C.~T6o 'd:~~~mmL-Cr~'?~~2fs:(7)~jJ;~ • • L~~~if:,6::"1::~~mV"T6o~2fs:~~~ Figure 7.
Forbesiceras mikasaense sp. nov.
Two atypical examples obtained from the type locality.
la-c. Phragmocone, with fine ornamentation and much compressed whorl, in K. Sanada's Collection; lateralCIa), frontal (lb) and ventral (lc) views, x7/8. 2a-b. Adult shell, No.129 of Y. Kera's Collection, somewhat
smaller and more compressed than the holotype; lateral C2a) and frontal (2b) views, x7/8.

32

PROCEEDINGS OF THE PALAEONTOLOGICALSOCIETY OF JAPAN

8 *i5"~~~~ 1981 ~~~ • lit~
B*il1=.¥J.J~~~~· ~~t.M987~ 1 ~30B-2~1BK~~*~~~R~l~~~~I~~m*~**-,J,--r:~tHlli~.nt.: (~1JIl~ 231 :f5)o,,;;:,.',r.~gA I rJrUE~t'::'Mt7.>1=.¥J.JQ)*{I:.

~jI t .:t:" .nt.::.~;iI-r 7.> ${tI: J

i!!:~A± Jlm-. fM~,Jlli$= • 'Hit~

iI.m~~&AkJr.~eK~~7.>B*~.Q)&

Ii: ............................... .JA~~~
Jr.~eI1JiM~Q)*{1: t ([jH~${1\= ... .~iR¥~
Jr.=~;(if~L!k{I:EMQ)~jlt.::.A&.n7.>${tI: ....

· ................................ *:fr~1.ffll)
Neogene climatic features and events ofnorthern China ................ Liu Gengwu
Ill· *VIt*JUJ{Q)iIlI:Ilt t li!IJ;(ifflQ)$;JL~mtJ, &A
t.:${tI: ............. , .......... 'H2:~l1!l:~flI)
Jr.-=~([ij1=.PiIl1LiI)¥J.JMQ)f!rjl........ ~Iii\f~~

OOM!*tM~~ IiHt$&i!I.2@~~~~([ij.K~-r7.>~~,,;;:,.',r.~gA(Wagga Wagga, Australia) ............. .

· ................... 'J'ii1ii~~ • ± Jlm- ft!!
• 3 @11E1=.;(if~!k~~*~ (Geneva, Switzerland) .............................. ii1ii~i'f1f
Symposium on the Cretaceous Stratigraphy
and Palaeontology in the North China (if!
~,*/l!m) .............. ;;1q1~!Jij • EB:t1
~

}'lIJ

jl

~

~

B*Q) 7 ~"7 ,r.~Q)lItj%!!7Hfl .......... L1! JJ 1.fz
iifj~:IIH.~

Angiosperm paleobotany-.'j!{~ t llii4W.J~ t Q)~};';i:-............................ lIJ)j#-li\(flt
~

lit

11 A

~

-:n ,-C ....................... .
. .. .. .. .. .. .. ·*:t1~!Jij •{'fiR Jlm
Aurila-Mutilus Jiit (1l'~!k) Q)W!:~iiim~ ..
~EBJtJlm • ilf2:fr{WZ
Aurila-Mutilus Jiit (1l'~!k) Q)*k!C~~~f*. ....................... ilf2:fr{WZ • ~EB JtJlm
1l'~!k Cythere JiitQ)1=.~U~Q)~ft~ t .:t:"Q)flr,,'t.::.
~~7.>:i:~ ........................ ~~ '/?:fIlffiJri!!:Q) Stylosphaerinae lII!f4t.::. -:n '-C ..... .
................................... i!!i:t1!JijT
T,r. :,.' *m.~ 1 IJ it I±I Lt.: Receptaculitid t.:t:"Q)7HJU:Q)&1i: ....... ·'JCT~l'i'J • ~EBJlm±¥J.JQ)~{I:Et.::.

~~~IIMit{I:E"\" 7" v 7lofJ" g:7,r. .,;;f4t.::. ":n '-C ..

· ..•...•.............•.........•• 1*I1Il11iJt:t:M
B*if!1=.f\:;Q) Ptilophyllum Jiit ............. .
· ... *:t1~!Jij • *7E~T • *~1Ji!: tx:. -g~*lil'i'J
T~!li'<Q)r$l~r~*JjtTIIMtJ, &itlli Lt.:~JHllii•••••••••• dli*_-·••••••••••••

Cretaceous corbulids from Japan. Part III.
Corbula and Nipponicorbula ...... Kozai, T.
BlII!*,c~jijJ!l, "Trigonia deckeina" Kubota t.::.

'?t '-C .................. EBf\:;lEZ • if!:t1~!ijQ).~7t:;ffj t fJiIlt.::. '?t,
-C ................................ ii1ii*~!ij
BlII!eJ41it~7 :/.:£:7'1 r Polyptychoceras ~Q)7t1!tt.::.~-r 7.> :PH~iM" ........•..... !f-JII~>:ij:l =- 7 .,;; 7 :,.' • 7 :,.'.:£: 7' 1 r
Prionocyclocerast.::.'?t,-C .......................... =l:i!i\(~*nit Forbesiceras (BlII!~7:,.'.:£:7'1 r) t.::.
'?t,-C ............................ ~*~~~
Dosinia (Kaneharaia)

Tiny Ammonite Worthoceras from Hokkaido.............. Matsumoto, T. and Yokoi, K.
7·:rv71lJH.::.ii~7.>=~jg: (dimorphism) t.::.,?

t,-C.~ ...... t~*~flI)· ii1ii~JEt~. JIIrm::t:~~Dimorphism in Hauericeras, a Cretaceousammonite genus .......... Matsumoto. T.,
Toshimitsu, S. and Kawashita, Y.
i!!iK¥i'f• • Q) .,;; T ~ -t: :,.' 711 Lingula ana tina~[jjQ)jI~m~ ......... ,1J'iR~1=. • ~t1: MJ
v\1fEQ Millerella 1itit Weiningia Jm~JE.
JifH.::.'?t,-C .............. ~EBff-· t~*;fI:lz
if!Jrk!C1j~~~!G'1I (~JIj(IIM) t::.it-r7.> =- v:,.'
f4~1!tQ)7t~ ...................... ~.~~Wlif!1fr1it Hipparion (g .... f4·PiIl1L~n Q)*k!C~f*(.K.779~t~-:7.,;;7Q)~'ofJ"K'?t ,-0 .................. iJ.UIlJ!i;A • {'f:fr~~
Thyasira bisecta Q)it:IJ.:tJ, &btJ,7.>':: t ..... .
................................. t~Ii5ID$G-flI)*~BlII!e~jijJ!l,Q)= 9 7Q)~~t~,i&~l:i ..

33....... " ............... 1II~iEz • f'~1II tl'r'j] 'j]* ~ 'j]*1 (Phacosoma japonicum) q)W!:q)}jj(;~~WHJT c -t' q)tl~~"¥:((.J,lf.~ . ............ .

.. .. .. .. .. .... W1i)fl-}jj(; • ;;tcf~,/H'· *~,';!;',,;H
i1!iiW Ef *?HIHfrttc::*i!€~fJO't~flIIq)Jjj(W!:I'::' -:n,-C ............ lZIr.&t!t • mlIlJJltIllt· Wlffil-rPt
7',r. /';f.C!llJEM Orecopia kobayashii Kase andNishida q)~~fJfti!:; ................ Jmitfihi:!t~I;jt7U~~rn~*Jjj(T.pq)1!\lilm-tt /' :z*-{:M~ II ....

........................ :JfilJJltx • f'~lIIf$-tl!
~~~q)~.~.~~ft~M •....................
~ J{f III'& t!t • ~HE

tl'. ~ i;t JII ~fIl • 1:!fjljIB

Miocene physeteriel teeth assemblage fromNakamachi, Naka-gun, Ibaraki Prefecture· ... Hasegawa, Y., Koda, Y. and Kasai, K.
~J111lri ffi-it!2~ q)m:j@;q)JEfMiq)li1f'§t: ............. .

Ef~~·* l!1fL.!IlL

piJJiW· ~ 1llt1>'!llJ~~q)W!:offilm~~~~~¢h"¥:((.J£~-~~~
ltrMI.::.~~¢~fI![~~- ............ ~III;fIJt:

H~JIjj~~fJTt.:. J: ¢ 9c~It~f\:;q)jt~~1E~HH'::' ":>1.'(Umbonium (S.) giganteum) q)W!:I'::'.7;.l?h¢Mt~~~ .......... ..

~titajti!l !f1;-¥!1!jJi\i'~J1'J!1!!llilt q)itfiWlIl q) J'lM ft~M

m.~:lI'/'''14'--tt::f....... " ............... liIilIl ~. ± ~zg....... ........... ~~~j[Biffi*c7 /'-{:-;J-1 r Tetragonites q) fi(J I'::'":>I.'-C ............................ MLIJJltJ'{;!llJEMJjj(W!:q)~w(ft~~';f.C~~~~'~M7/'-{:-;J-1rq)7~~'~q)i'ljUlBmil!1 ............ 4Z!BLjt· fflilIl7i1=.

r Nipponites q)~~1Jq);m
Wl11:c&M'!.\11: ...................... ~* ~JmiJEjI)~q)D:\(MJI1J~iIJt ... ~? - /' c -t' q) -{: 7'IV . .••~'M'~~ 7 /'-{:-;J-1•..• ··.· .•.•.• ·· .•. ···· •••..•..•.•• mI'Ii']$~
Laqueidae t.::.:t-ovt ¢ 7 P,I. r Y - ••••

JmiJE!lliJ~................................... ~.-f±i'fWi '7 ~ .:>. Y Metacrinus rotundus q)~q)nli:~~& c -t'q)~IiEB''.I;lf.~ .............. *i1lt!t1=.
;i§1ili\11:-tt /' :Z'llFf,fi:q) ecomorphology c 7 , , ?
I v lX5G ....•••......•••.•..•..•..•. .p~
1j!:
Sagenopteris inequilateralis Oishi q) cuticle........................ ~ fit",· *-tt~Wl
iWffil~t1:I1J:l1!!C::1i;f.C~.IfMt~ q)itili~iIli c -t'q)~lil{~Jj[ ('T¥fl) ........................... .

.......... tlf;IIIM::t:M • ~rm~~~ . 1J1l. ~~Jjj(-¥~q)J!fJi'~o / i*:~ll:fitJ'lm.!a .. :WiIiilf~~
Pif.1J~Jj[I'::':t-ovt ¢ ~W!:q)~M ................. .
........................ l"!.UlE- ..tl! r~flB• &:z7q)~.· • • ~~~~K£~<~~'l4'- - ita~fti1Iq)tl~Jj[MfJT .......... *~,'it'.jt~~mllltiJ. l?.7;.t.:J!fJi'tltii1rWlq) ita 7.KiIli l!'rjl)-/irI1J~jiJi}11 ~I'::' ":>1. '-C .......... ~tt;f~¥.f
1 ~-tt /' ::f'Ftmiff\:;"¥=iJ· l?.7;.t.:7tfJi't!tital"F~-!Jlq)~~WMfJT ........................ 'H§Il~·:JfoJit:· ftc.!fu.· 'H~-~· ~m~Z~~.~ll:fK~c~<iWffilAffl.WlfJi'~~q)~.

l!'rft ............................. . ~ti~~
MIII~::t:.WiWi1!iffilK~~~¢~.~~itJ'lM~~.................... .. i1-14I§rl· 'Nih 'Ii']~ffl~ iWitar'7&~~~ita~q)m.~&~~R.!all:f~........................... . M5G;W~

W~~i1!iffilitalliltq)&~:f-j:rL.!all:f •................

........................ fff;f~~ • it!2Jjj( li1f...... ~!1I;jtT
fJf:$. it!2tiftllz

fjg~-¥~.pfJi't!t1l'm.!aMI'::' ":>1. '-C~iiIJf.1Jq)1l'm.!aM~ ........ ;m· . .. !IlL

-C ............................... ,1J,it!2r~r• (-t'q) 2) ........................ Jf;*Wl[g~t#&jtq) J!fJi'l!tt.::.:t-ovt ¢ iffil.1!l11:J'lMM~q) I1i1li c-t'q)~t'£ .............. .. liF~'iTm • ~f± 'I\lt~.~&~~K£~<~'7:z'71'j]q)if~1E~
c~,e.m.!&q)j'ffi~ ........ ;#:1: jft£. *~,'it'.jt

Ef*$q)ffl.1=. Mollusca q)~.~&~~ ........
...................... ~i;tJII -'¥.. *~,'it'.jt
1=.~ft~iJ· l?.7;.t.:~m.!$*tJejt:1!iq)t~jt • tI~iI!t~
A ............................... ,1J"!"rfi'l'*7~-{:~q)*~r':Z-:lI'-t'q)4-~a~Mc...................... ft1!i;t~zg*:W1ili\:l1!!~&~i'f:rL.!a q)j\Iif3!:ft ............... .
....................... .miR. ~. ~t.!l! l"F¥:'Iili\:l1!!~&1=.:ff:rL.!aq) s *;m;l,H.::.:t-ovt ¢ ~~I'::' ":>I.'-C .................... ~iIiilft:~· ~t.!l! l"F
Polynemamussium alaskense I'::' ft!iff l.. -C 1=.~~¢&~i'f:rL.!at.::.":>I.'-C .... J¥*gA'z· ~t.!l! l"Ft'£~q)~f,f,-~~!1I;~1:~~~7.K11:~iliMK:t-ovt¢&~q)~~c&~W!:q)~nt~m ................ ~~ ~ffli:l1!!11 (7',r. /'*) q):z / ~ /' roo .......... ..
· ....................... ~~~~ • 'tCit~r~.I1J:l1!!a~iW*,

EEfm-.~*:l1!!lliltK:t-ovt¢;; ~ ,*,cD:\(!ft.!aIlFf ................ :t~lIIm~~ ~ ,*cD:\(!ft.!a Tricolocapsa plica rum c
Tricolocapsa conexa q) I1fIl:((.JJIJ~~ft ..... .
................................... f'~~ m
Fi~I1~q)l¥lh}11::ff:rL.!aI'::' J: ¢ :l1!!'i!fif~I'::' ":>1. '-C· . . . . . . . . . . . .. ± ~-. !f.lX~ • ~*~r.~~J:~.7;.~ft.~q)~il!1-Ef~I1D~~~

iU.RiiiJ· Jii[;#: -'¥.
...... 'H~ m
JJnAjt,ilEq).pfJi'llt-tt /' ::fft~ ................. .
........................ r'IIIJiA • *~~M
~tlfajt1:ffilBiffi*it1 / ~, A ~fJj-~.J:ll:J'lq) 1 fiI!
m ........ , ....................... tIJJ'{;~=f~~~H~-¥~iliil1Jq)=f*l!l~:WIIiJ· I? 7-tt 7l* 'j]'
1 f.4 Hartungia sp. q)itili .. · ............ ·.. .................... /ir1Il ilt· *~,Jlli$~
iIJt.$.~ffli:l1!!fti1I7.K~ 'T i;tiJ· I?it~ ¢ J'lJlJ.!aft~I'::''':>I.'-C ......................... ·'tCit~rl.. -C- .................. i1!i~titajtl.:.:t-ovt¢ffitt~*&~I1Ff

34

:it
00
"1ffLElu::.M-t :M-*@i c t:7':k .......... ~t!!! iF

tltlf,SA .. )i7Jcm~~~~~~llrmM7~7~vif~~iolt~ii~!I1IJ:lt!!I!J

tltlf,SA-/:/,.r.:;?AO):±'~.................................. ~~{,5rJll
ffilill7ot,-ij-"'?Y-rK;t.;ttQ~~tt~R~K~Q:ttI?'ffi{'¥f\'; ................ Ji€EIl:t:R • f:k5Cfj]~~ra'+.~

r ~ -1 7·j~!L*0){!i'dtl::'"')1, 'LJ

ffilill 7 ot 'Y -ij-"'? P·-rl::.;t.;tt QW~7J';(flO)f{£~ ....

~~{ijflJ].................. 'i'Ji~{DfIJ]

ffilill7ot'Y-ij-"'?Y-rK;t.;ttQ-r://~EO)~~~:ttI?JlI[c'¥f\'; ....................... ·IHilEll~jiA:;

ffilill7ot'Y-ij-"'?Y-rK;t.;ttQ~~~R~0)~~~:ttI?JlI1. .............................. ::It!!!

rr,

mlill7ot,-ij-"'?Y-rK;t.;ttQR.~EO)~~~:ttI?
JlI1. ..................... .~j:§m~ tl!iU~!ii:•~1fWIDfo

New members approved by the Council Meeting held on January 29, 1987.
Ordinary Members:
Motoyama, Isao; Taguchi, Eiji; Azuma, Yoichi; Kojima, Satoru; Veno, Katsumi; Murakami,
Shiod; Sasaki, Takashi; Saito, Shigeru; Kashima, Kaoru; Morita, Kanichi; Kera, Masatoshi;
Kera, Yasuji; Wakamatsu, Hisanori; Kikuchi, Masanobu; Kanazawa, Kenichi; Veno, Hikaru.
Fellows:
Adachi, Shuko; Abe, Katsumi; Amano, Kazutaka; Okada, Hisatake; Ono, Keiichi; Kaiho,
Kunio; Sashida, Katsuo; Sugiyama, Tetsuo; Taketani, Yojiro; Hatta, Akio; Matsui, Seiichiro;
Yazaki, Sumio.
Deceased Members:Sunouchi, Ikuo; Makiyama, Jiro (Honorary Member).

1987-if 136@J f91J~

jill

Hli

00

E:I

~i~$j6**W B

1987iJ'.6 Ji 20 B -21 B

1987-if 4 }'j 5 B

it00

fijf *.TI:t.!!j:~tg,{>;'+;I)' C, r:1I1I:I)O)::!Jj\')'J{~ll::t= >j.- I) i L t:.o -: tU= 1'-1"-:> -CliO¥:O)l'i!lJ:Ji (Plate) (j:T« -C jiJl~ (Figure) I: >j.- I) iTO) -C", fl:E O)¥J'{>j.' I:' Ht. J., jYi1';-(j:~*O) rlJ I: fk ~ (j: 15 x 20cm O)~(i:JHl r"J t= An-C <t! ~ \ '0 t:.t! L -: J: I) 'J' ~ \ d#f,-(j:ff~O)* ~ ~ -C"fPf\, i -It h,;/}1, 1Jl!-t ~ ;ffi~T J., i#f}(j:>j.' J.,« < I)Jl5cm~ J., \' (j: 7 cmO)~[i)lijl"J t= An -C < t!~ \ '0

n

t-;

:.

tJ

t

I)

*lfliltJ:jl.:J:: t= (j: UU'i:1H"~ -:> -C t, f,') -t,:fj-t= J: J., ~~5((j:, 'llif!i) I: L -C )n]--',j-I= (j:t~.x ~ n>j.'I') I:~I) iTo *'.}0)825 I: 8270)=~iB5c(j:-:nl=tlH\Ij!\,t:.LiT;/}{, No.1431:f,1);f£I=*iil~0)ll/,{'l" J~J.'ff9i) I: L -c-tIH&\ ,t:. L it L t:. (~~~ i U~)o

1 9 8 7

iF 4 ,i 25"

I'll

1 9 8 7{r- 4 Jl 30 II

fe

ISSN

II

!VJJ

8 *"f:~4jLmk;' !1-rJ.1(jliHH1~

0031-0204'* 't "* 'Wil,' •
t,-

*

B
il ~ ~ ~ ~:X::lJ\ [){ ~t ~ 2-4-16

~

(',11

ji't*J$~!i'iE'*i3n~~ ~ .~f[: .~F.P
2,5001'):J!O¥.

,\jIIJif

8 4 78 O~)

ilfi 03-817-5801)~iIl',:;:;iE'l'f HI fir i,]* :lJ( *iii ,%'1111"* *r txi ilf ~n Jill] ** Jot ~ 1±('If!:[K ~ :E ~t 2 0) 13',iii;

FE

i1il~t03-991-3754)

Transactions and Proceedings of the PalaeontologicalSociety of Japan

New Series No. 145

April 30, 1987

CONTENTS
TRANSACTIONS
825. MATSUMOTO, Tatsuro and SAITO, Rinji: Little known ammonite Grandidiericeras
from Hokkaido (Studies of Cretaceous ammonites from Hokkaido-LVIII) ....... .
826. TAzAwA,

Jun-ichi and TAKAlZUMI, Yukihiro: Poikilosakos (Oldhaminidina,

Brachiopoda) from the Permian of northeast Japan. . . . . . . . . . . . . . . . . . . . . .. 10827. MATSUMOTO, Tatsuro: Notes on Forbesiceras (Ammonoidea) from Hokkaido(Studies of Cretaceous ammonites from Hokkaido-LX) . . . . . . . . . . . . . . . . . . ..

16

PROCEEDINGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

32