ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan

New SeriesNo. 183

September 30, 1996

Co - Editors

Kei Mori and Kunihiro Ishizaki

Language Editor

Martin Janal (New York)

Editorial Board

Shiro Hasegawa (Hokkaido University), Hiromichi Hirano (Waseda University), Kunihiro Ishizaki (Tohoku
University), Tomoki Kase (National Science Museum), Kei Mori (Tohoku University), Kenshiro Ogasawara(University of Tsukuba), Yoshihiro Tanimura (National Science Museum), Yukimitsu Tomida (National Science
Museum), Kazuhiko Uemura (National Science Museum), Akira Yao (Osaka City University)
Officers for 1995- 1996

President: Tsunemasa Saito
Councillors: Kiyotaka Chinzei, Takashi Hamada, Yoshikazu Hasegawa, Itaru Hayami, Hiromichi Hirano,
Hisayoshi Igo, Noriyuki Ikeya, Junji Itoigawa, Tomoki Kase, Tatsuaki Kimura, Itaru Koizumi, Kei Mori ,Hiroshi Noda, Ikuwo Obata, Kenshiro Ogasawara, Tomowo Ozawa, TsunemasaSaito, Yokichi
Takayanagi, Kazushige Tanabe, Akira Yao
Members of Standing Committee : Kenshiro Ogasawara (General Affairs), Tomoki Kase (Financ e), Kei Mori (Editor in
Chief, TPPSJ), Kunihiro Ishizaki (Co - Editor, TPPSJ), Hiromichi Hirano (Planning), Hiroshi Noda (Membership; Co Editor, Special Papers), Noriyuki Ikeya (Foreign Affairs), Kazushige Tanabe (Editor, "Fossils"), Juichi Yanagida(Editor in Chief, Special Papers), Tatsuaki Kimura (Friends of Fossils)
Secretaries : Katsumi Ueno, Shuko Adachi (General Affairs), Masanori Shimamoto (Editorial of TPPSJ), Yasunari
Shigeta (Finance), Makoto Manabe (Planning), Katsuo Sash ida (Membership), Robert M. Ross (Foreign Affairs),
Kazuyoshi Endo (Editorial of "Fossils"), Akihiko Matsukuma, Takeshi Ishibashi (Editorial of Special Papers),
Tamiko Ohana (Friends of Fossils)
Auditor : Ryuichi Majima
Copyright Statement

The appearance of the code at the top of the first page of an article in this journal indicates that for any
kinds of copying the copier must obtain permission from the following organization which has been delegatedfor copyright for clearance by the copyright owner of this publication :The Copyright Council of the Academic Societies
41 - 6 Akasaka 9- chome, Minato- ku, Tokyo, 107 Japan
Phone : 81 - 3- 3475 - 4621
Fax :81 - 3- 3403 -1738

Cover: A terminally resorbed maxillary tooth of iguanodontids (Ornithischia: Ornithopoda). The specimen is .
from the Kuwajima Formation , the Neocomian section of the Tetori Group, in Shiramine- mura,
Ishikawa County, Ishikawa Prefecture, the west coast of Central Honshu, Japan (Shiramine - mura
Board of Education, Coli . Cat. No. SBEI 001 , 23 mm in dorsoventral length).

All communication relating to this journal should be addressed to the

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

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp.485-499, 7 Figs., September 3D, 1996

© by the Palaeontological Society of Japan 1996

Early loop ontogeny of some Recent laqueid
brachiopods
MICHIKO SAITO
Paleobiological Laboratory, Geological Institute, Faculty of SCience, University of Tokyo, 7-3-1 Hongo,
Bunkyo-ku, Tokyo, 113 Japan

Received 14 July 1995; Revised manuscript accepted 10 April 1996
Abstract. The early loop ontogenies of nine Recent laqueid species from Japanese waters were
examined using scanning electron microscopy. Although juvenile specimens representing certain earlyloop stages were not available for some species, all the examined species appear to share roughly thesame early stages of loop development as described by Richardson (1975). However, some differences
and characteristic features exist in the early stages of loop ontogeny, such as the disposition of the septal
flanges and presence or absence of septal bifurcation, characters which appear to be invariable at thegenus level. A prime example is the case of the affinity between Laqueus and Frenulina, which haveoccasionally been included in the same subfamily. Inspections of loop morphology of early growth stages,
especially of the above characters, indicate that these two genera may not be as closely related aspreviously thought.
Comparison of relative timing of loop development as standardized by shell length reveals some variation
within a species, but no major variation among species. Heterochrony is evident in one laqueid species,'Frenulina' sp., in which adult individuals have a loop of juvenile morphology in other species.
Key words: Brachiopods, Laqueidae, loop development, ontogeny, heterochrony
Introduction
In terebratulide brachiopods, the lophophore is supported
by a calcareous brachidium, or loop. The form of the loop
undergoes considerable change during ontogeny, and boththe form of the loop and its mode of development have beenof prime importance in terebratulide classification. For
example, Richardson (1975) investigated relationships among
long-looped Cenozoic terebratelloid genera belonging to the
Dallinidae, Laqueidae, and Terebratellidae, and proposedthat patterns of resorption of the ring (an element of the loop
at an earlier developmental phase) can be used as a diagnostic character to separate these families.
MacKinnon (1993) has drawn attention to the potential forstudies of early loop ontogeny to provide valuable clues forestablishing phylogenetic relationships in terebratulide brachiopods. However, the early growth stages of many
species have not yet been satisfactorily studied.
This paper describes the loop development of nine extant
species belonging to the family Laqueidae based on material
from Japanese waters. The loop development of laqueid
brachiopods has been described by several authors such as
Atkins (1959) for Terebratalia transversa, Hatai (1939) for
Coptothyris grayi, Konjukova (1948, 1957) for Laqueus californicus and Terebratalia coreanica, and Richardson (1973a) for
Frenulina sanguinolenta. However, none of these studies

utilized scanning electron microscopy (SEM) which allows
detailed observations of microstructures even for very small
specimens. Gunji (1987) studied the mechanisms of loop
ontogeny after the late haptoid (or diploform (MacKinnon,
1993)) phase for dallinid and laqueid species, and explained
the inter-specific variations in terms of developmental constraint. But inter-specific variations before the haptoid
phase remained unquestioned. The present investigation,utilizing SEM, aims to describe and compare the morphology,
particularly of early growth stages, growth patterns, andrelative timing in the development of the loop of the laqueid
species available to this study.
Material and Methods
Samples of a total of nine laqueid species were available
for this study (Table 1).
They include both living and dead specimens. With living
specimens, care was taken in the removal of soft tissues
using domestic grade bleach (sodium hypochlorite: approximately 5% (vIv)), as described by Mackay et aI. (1994). After
opening the conjoined valves of dead specimens using ascalpel blade, dorsal valves were placed briefly in the bleachsolution. Each specimen was then washed, allowed to dry,
and mounted on SEM stub. Specimens were coated with
Pt-Pd alloy prior to observation by scanning electron micro-

Michiko Saito

486

Table 1.

Samples used in this study.

Species

All localities are in Japan.

Locality

Depth

Status125-193 m
80-186 m
82-144m
52- 98 m
72- 76 m
50m
32- 35 m
50-75 m22-75 m12- 40 m
20- 30 m
52- 98 m
104-106 m

D
L
D
L
D
D
D
D
D
D
L
D
L

Terebratulida
Laqueidae
Laqueus sp.
Laqueus rubel/us (Sowerby)
Pictothyris picta (Dillwyn)
Pictothyris sp.
Terebratalia coreanica (Adams and Reeve)
Coptothyris grayi (Davidson)
Frenulina sanguinolenta (Gmelin)'Frenulina' sp.
Jolonica nipponica Yabe and Hatai

off Hachinohe, Tohoku
Sagami Bay
off Hachinohe, Tohoku
off Shimoda
off Tsukumi, Bungo Channel
Otsuchi, Tohoku
Wakkanai, Hokkaido
Otsuchi, Tohoku
Wakkanai, Hokkaido
Miyako Island, Okinawa
Ogasawara Islands
off Shimoda
Izu Islands

Abbreviations in the 'Status' columm: L=living specimens when collected; D=dead specimens when collected.
scope (Hitachi S-2400S). All of the specimens utilized
except one (specimen 28498 in the collection of Tohoku
University) are housed in the University Museum of the
University of Tokyo (UMUl).

Loop terminology
Loop development is a continuous process, but for ease of
description, loop ontogeny has been treated as a series oftransient phases. The terminology applied in this study
follows that of Richardson (1975) and MacKinnon (1993) withminor amendment (Table 2).

Table 2.

Results
Loop development of the examined species
Laqueus rubellus (Sowerby)
None of the available specimens of Laqueus rubel/us
exhibited the earliest growth phases of the loop.
Annular phase
A specimen 3.8 mm long (the shell length describedhereafter is that of the dorsal valve, and denoted as L) shows
the loop pattern of phase 5 with a ring and complete
descending branches.

Definitions of the loop development phases used in this study.

Prebrachidial phase: Dorsal valve without any brachidial structures.
Axial phase (early): Phase of loop development with a low medium septum.
Axial phase (late): Phase of loop development with a septal pillar and flanges. This development of septal
flanges is distinctive feature for laqueid brachiopods.
Cucullate phase: The formation of the septum and the hood.
Annular phase: The presence of a ring in place of the hood.
Haptoid phase: The anterior fusion of the attachments of the ring and the descending branches.
Bilacunar phase: The presence of two lacunae in dorsal segments of the band forming the ring.
Bilateral phase: The presence of two pairs of connecting bands, lateral and latero-vertical.
Latero-vertical phase: The presence of latera-vertical connecting bands only.
Trabecular phase: The presence of lateral connecting bands only.
Teloform phase: The absence of any connecting bands so that the loop is free of the septum.

Figure 1. 1-6. Laqueus sp. 1: Specimen UMUT RB19818 (L=0.6 mm: L is the length of the dorsal valve). 2:
Posterior view (L=1.9 mm), specimen UMUT RB19819. 3: Dorsal view (L=2.0 mm), specimen UMUT RB19820. Part of thehood is broken. 4: Posterior view (L=2.7 mm), specimen UMUT RB19821. The descending branches from both septal pillar
and crura have just united. 5: Oblique view (L=4.4 mm), specimen UMUT RB19822. The transverse band of the ring isbroken. 6: Specimen UMUT RB19823 (L=4.2 mm), dorsal view. The transverse band of the ring is broken. 7-8.
Pictothyris picta. 7: Specimen UMUT RB19824, dorsal view (L=1.2 mm). The right hand part of the shell is broken. The
septal pillar is the first brachidial structure to appear and the cardinal process is also differentiated at this stage. 8: Detailsof the septal pillar in Figure 1-7 showing the small septal flanges on the posterior edge.

1015.

~

SOOllmLoop ontogeny of Recent laqueid brachiopods

487

488

Michiko Saito

Bilacunar phase
A specimen (L=4.6 mm) exhibits the loop of the bilacunar
phase.
Bilateral phase
Specimens larger than 5.9 mm in shell length show theadult loop pattern (bilateral phase).

Laqueus sp.
Prebrachidial phase
The smallest specimen approximately 0.6 mm long displays no loop-supporting structures (Figure 1-1). Socket
ridges are well developed.
Axial phase (late)A specimen of 1.9 mm in length has an anteriorly bifurcate
septal pillar (Figure 1-2). A pair of posterolaterally divergent
septal flanges extend from the posterior edge of the septal
pillar. Crura, bearing short crural processes, project fromnear the base of each inner socket ridge. Short segmentsof descending lamellae diverge anterolaterally from the distal
ends of the crura.
Cucullate phase
In the next smallest specimen (L=2.0 mm, Figure 1-3) ahood forms on the posteroventral edge of the septal pillar
which is bifurcate along both anterior and ventral edges.
Two small septal flanges project from the posterior edge ofthe hood. Lower down on the septal pillar the rudiments ofthe descending lamellae appear as a pair of narrow triangular fins with smooth ends.
Annular phase
Shells of 2.7-4.6 mm in length show complete descending
branches extending from the crura to the septal pillar and aring having traces of flanges (Figure 1-4). As the shelllength increases, the flanges become smaller due to resorption. The anterior edge of the septal pillar is strongly
bifurcate and spinose.
Bilacunar phase
At the bilacunar phase (L=3.8-4.6 mm) a pair of lacunae
are present in the dorsal segments of the bands that form thering (Figure 1-5). At a shell length of 4.2 mm (Figure 1-6) the
lacunae are enlarged and the growing (anterior) edge or thedescending lamellae become progressively more divergent.
Pietothyris pieta (Dillwyn)
Axial phase (early)
The first structure to appear, associated with the formationof the loop, is the septal pillar which forms as a thickeningof the midsection of the dorsal valve approximately 1.2 mm
long (Figure 1-7). In this specimen, the socket ridges are
low and the cardinal process is beginning to develop. The
septal pillar is relatively wide and bears a pair of septal
flanges on the posterior edge (Figure 1-8).
Annular phase
A specimen 3.2 mm long shows complete descending
branches, and the ring (Figure 2-1). The anterior edge of the
septal pillar is spinose but non-bifurcate.
Haptoid or bilacunar phase
A spcimen 3.9 mm long has a loop in the haptoid orbilacunar phase, with two lacunae in the dorsal segmentpartly broken or the band forming the ring (Figure 2-2). The
ascending and the descending branches are connected.
Bilateral phase
Specimens ranging 6.0-6.9 mm in length shows the bilateral loop pattern (Figure 2-3) with two pairs of connecting
bands, lateral and latero-vertical.
Latero-vertical phase
Specimens larger than 8 mm in length show the adult loop
pattern (latero-vertical phase), with latero-vertical connecting bands only.

Pietothyris sp.
Prebrachidial phase
The smallest specimen (L=0.6 mm) displays no loopsupporting structures (Figure 2-4). Socket ridges are low
and the cardinal process is not developed.
Axial phase (early)
The next smallest specimen (L= 0.8 mm) has a low septal
pillar, but cardinal process is not yet developed (Figure 2-5).
Axial phase (late)A specimen 1.5 mm in length shows well-developed, laterally directed septal flanges and a high septal pillar. At thisgrowth phase, the ventral (growing) edge of the septal pillar
is non-bifurcate, but just anterior of the septal flanges anarrow triangular area develops. The edges of the flanges
and the anterior triangular border attached to the flanges aresmooth (Figure 2-6). In another specimen of length 1.5 mm,a slight depression begins to form on the ventral surface ofthe triangular area, and very small secondary layer fibers
appear within its margins (Figure 2-7). This indicates the
beginning of a groove to form a hood (Figure 2-8). The
cardinal process begins to develop during this stage, andFigure 2. 1-3. Pietothyris pieta. 1: Lateral view (L==3.2 mm), specimen UMUT RB19825. 2: Anterior view of dorsalinterior, specimen UMUT RB19826, (L==3.9 mm), showing the bilacunar phase. Most of the ring is broken. 3: Specimen
UMUT RB19827 (L==6.9 mm), anterior view, showing the bilateral phase. Although most of the loop is broken, lateralconnecting bands and right latero-vertical connecting band are seen. 4-8. Pietothyris sp. 4: Specimen UMUT RB19828(L==O.6 mm), dorsal view. 5: Dorsal view (L==O.8 mm), specimen UMUT RB19829. The septal pillar has formed, but the
cardinal process is not yet developed. 6: Detail of the septal flanges of specimen UMUT RB19830 (L==1.5 mm). 7: Detailof the septal flanges, dorsal view (L==1.5 mm), specimen UMUT RB19831. Secondary shell mosaic is developed in thetriangular depression just in front of the septal flange. 8: Details of the flanges, dorsal view (L==1.7 mm), specimen UMUT
RB19832. The ventral edge of the septal pillar bifurcates to form a groove which is overlapped in turn by the septal flanges
thereby forming a hood.

1015.

Loop ontogeny of Recent laqueid brachiopods

489

490

Michiko Saito

rudiments of the descending branches appear on the septal
pillar and as extensions of the crura (Figure 3-1).
Cucullate phase
A specimen 2.1 mm long presents a small hood (Figure 32). The hood becomes deeper, and the shape becomes
more rounded with growth (Figure 3-3). The crura and thedescending branches extend further toward one another andposterior resorption of the septum also occurs.
Annular phase
The specimen UMUT RB 19836 (L=2.3-2.5 mm, Figure 34) shows the ring with rudiments of the flanges and still
unconnected descending branches. In specimens of shelllength ranging from 2.8 to 3.1 mm, the descending branches
are complete.
Haptoid phase
In specimens 3.4-3.8 mm in length, the leading edges of
the ring and the descending branches unite and being toseparate from the septal pillar (Figure 3-5). These specimensof Pictothyris sp. are similar to P. picta when 3.9 mm long.
Bilacunar phase
At a shell length of 4.9-5.2 mm (Figure 3-6) the fusedascending and descending loop elements extend well forward of the septal pillar and lacunae perforate the anterior
and dorsal segments of the ring.
Bilateral phase
A specimen approximately 7 mm long has the loop in thebilateral phase, with lacunae perforating the anterior anddorsal segments and lateral connecting bands extending
from the septal pillar to the inner edges of the descending
branches.
Latera-vertical phase
Through resorption of the lateral connecting bands (Figure3-7), the descending branches become completely free fromthe median septum (latera-vertical phase). Specimens larger than 8 mm in length exhibit this adult loop pattern.

Terebratalia coreanica (Adams and Reeve)
Two small specimens of Terebratalia coreanica collected at
Otsuchi Bay provide some knowledge concerning the loop
development of Terebratalia coreanica.
Annular phase
The smaller specimen (L=3.3 mm) shows the ring which
retains the rudiments of the flanges (Figure 3-8). The
anterior part of the median septum is bifurcate and the
cardinal process is well developed. This growth phase of

the loop is similar to that seen in Laqueus sp. at shell lengthsof 2.7-4.6 mm (Figure 1-4).
Bilacunar phase
In the larger specimen (L=4.7 mm), although both thedescending branches and almost the entire ring are broken,
the posterior part of the septum and lacunae in the lower partof the ring can be identified (Figure 4-1, 4-2). The loop
pattern at this growth phase is similar to that described for T.
transversa at a shell length of 6.4 mm (Atkins, 1959).
Trabecular phase
Specimens with a shell length of more than 8.1 mm show
the adult loop pattern (trabecular phase).

Coptothyris grayi (Davidson)
Axial phase (late)
The youngest specimen of Coptothyris grayi (L=1.3 mm)
displays a low median septum (Figure 4-3). The anterioredge of the septum is bifurcate, and on the posterior borderof the septum, a pair of small, ventrolaterally directed septal
flanges are developed (Figure 4-4). The leading edge of theflanges and the middle part of the septum are smooth. Bothsocket ridges and a low, transversely oval cardinal process
are developed; a pair of rudimentary crura is also present.
In a specimen 1.8 mm in length (Figure 4-5), the ventral(growing) edge of the septal pillar is prominently bifurcate.
The bifurcation widens slightly posteriorly until it terminates
against, and appears to be overstepped by the mediansection of the septal flanges. Within the zone of septal
bifurcation, small secondary layer fibers appear.
Cucullate phase
At a shell length of 2.4 mm, the septal flanges form theposterior border of the hood. Crura extend from areas at thebase of the inner socket ridges (Figure 4-6).
Annular phase
Although most parts of the loop are broken, the loop
pattern of a specimen 3.2 mm long (Figure 4-7) displays abifurcate medium septum and part of the ring. The loop
pattern of this specimen indicates some similarity to that ofLaqueus sp. at 2.7-4.6 mm, L. californicus at 5.2-5.5 mm(Konjukova, 1957), and T. transversa at a shell length of 5.4
mm (Atkins, 1959).
Bilacunar phase
In a specimen 4.7 mm long, lacunae perforate the ring, andthe anterior part of the septum is strongly bifurcate, butanterior fusion of the growing edges of the ring and the

Figure 3. 1-7. Pictothyris sp. 1: Specimen UMUT RB19833 (L=1.8 mm), dorsal view, showing a small hood, septal
flanges, extending crura, and small plates (future descending branches) on the septal pillar. 2: Specimen UMUT RB19834(L=2.1 mm), posterior view. The anterior end of the hood is beginning to expand. 3: Posterior view, specimen UMUT
RB19835 (L=2.3 mm). 4: Posterodorsal view, specimen UMUT RB19836 (L=2.5 mm), showing the ring with rudiments of theflanges, descending branches are not united. 5: Lateral view, specimen UMUT RB19837 (L=3.8 mm). 6: Specimen
UMUT RB19838 (L=4.9 mm), details of the loop. 7: Detail of junction between the left descending branch (right-hand sidein the figure) and the septum, specimen UMUT RB19839 (L=7.8 mm). As a result of resorption of the lateral connecting
band, the right descending branch has become completely free from the median septum. 8. Terebratalia coreanica.
Oblique view. Specimen UMUT RB19840 (L=3.3 mm). The descending branches and the top part of the ring are broken.

1015.

Loop ontogeny of Recent laqueid brachiopods

491

492

Michiko Saito

descending branches has not yet occurred (Figure 4-8).
Teloform phase
Specimens larger than 7.8 mm in length show the adultloop pattern (teloform phase).
Frenulina sanguino/enta (Gmelin)
Prebrachidial phase
In a specimen 0.7 mm long, no loop-supporting structure ispresent (Figure 5-1). At this growth phase, low socket
ridges are seen and a rudiment of the cardinal process andthe anterior borders of the developing hinge plates aredeveloped as thickenings on the valve floor.
Axial phase (early)
At a dorsal valve length of 1.0 mm, the area of the cardinal
process is defined, higher socket ridges are developed, andthe septal pillar begins to form on the valve floor (Figure 52).

Axial phase (late) to bilateral phase
Further development of F. sanguino/enta (Figures 5-3-8)
follows that of Australian populations in the patterns described by Richardson (1973a). The axial phase (late) of F.
sanguino/enta (Figure 5-3) is unique among examined
speCies because the direction of the flanges is downward.
This feature will be discussed later.
'Frenulina' sp.
'Frenulina' sp. from off Shimoda was first reported byHarada and Mano (1960), as Frenulina sanguino/enta (Gmelin).
They noted that Frenulina sanguino/enta is a common brachiopod and distributed in the waters of Hawaii, Australia, thePhilippines, Okinawa Islands, etc., and that their finding was
the first from Honshu, the main island of Japan. But, as
discussed later, the population that was thought of as F.
sanguino/enta by Harada and Mano (1960) is now considered
to belong to a new species of a new genus (D. MacKinnon,
personal communication), so it is designated here as'Frenulina' sp.
Axial phase (early)
The smallest specimen (L=O.7 mm) displays a low median
septal pillar which, at this stage, is essentially smooth andnon-fibrous (Figure 6-1).
Axial phase (late)A specimen 0.9 mm long shows a high, plate-like septal
pillar with small, laterally directed septal flanges (Figure 6-2),

Cucullate phase
At shell lengths of 1.5-1.8 mm, the ventral edge of the
septal pillar becomes bifurcate and is overlapped posteriorly
by the septal flanges thereby forming a depression (Figure 63), giving rise to the hood (Figure 6-4).
Annular phase
In shells between 2.3 and 2.8 mm in length, the hood
becomes a ring still bearing rudiments of the flanges (Figures
6-5, 6). At this stage the descending branches are not yet
complete. The cardinalia is similar to that of young specimens of Laqueus sp. and Pictothyris sp. in some features
such as the morphology of the inner hinge plates andabsence of the cardinal process. An individual 4.2 mm longshows more extensive descending branches and the ring
(Figure 6-7).
Specimens larger than 4.7 mm in length (the largest specimen ever collected is 5.8 mm in length) show the annularloop pattern with a ring and complete descending branches(Figure 6-8). In most adult specimens a ventral segment of
the ring is resorbed, so the ring is commonly incomplete, but
occasionally the ventral parts of the ascending lamellae may
unite secondarily to once again form a complete ring.
J%nica nipponica Yabe and Hatai
At present, juvenile specimens of J%nica nipponica are
not available. Some adult specimens of J%nica nipponica
collected from the Izu Islands have been examined. These
specimens (the smallest one being 6.3 mm in shell length)
show a loop in the bilacunar phase as described by Richardson (1975).
Comparison of loop developmental patterns
The size range of shell length for each phase of loop
development has been plotted for each speCies examined inorder to compare loop development amongst the various
laqueid species (Figure 7). However specimens at certain
phases are presently unavailable for some species (e.g.
juvenile phases of J. nipponica). From the available data
(Figure 7) it appears that all examined species share essentially the same early stages of loop development as described by Richardson (1975), but there were some differences
within speCies with respect to the shell sizes at which
particular phases of loop development were attained. For
example, in Frenulina sanguino/enta, ontogenetic variation in
the rate of loop development can be seen. The second

Figure 4. 1-2. Terebratalia coreanica. 1: Specimen UMUT RB19841 (L=4.7 mm), ventral view. The lacunae are seen
although the top part of the ring is broken. 2: Details of the loop in Figure 4-1. 3-8. Coptothyris grayi. 3: Ventral viewof specimen 28498 (L=1.3 mm), in the collection of Tohoku University. 4: Detail of the flanges in Figure 4-3, oblique view.
5: Details of the flanges in specimen UMUT RB19843 (L=1.8 mm). Secondary layer fibers appear on the middle part of theedge of the septum. 6: Specimen UMUT RB19844 (L=2.4 mm), oblique view. 7: Oblique view (L=3.2 mm), specimen
UMUT RB19845. Although most parts of the loop are broken, the anterior division and resorption of the posterior part of themedium septum are seen. 8: Specimen UMUT RB19846 (L=4.7 mm), details of the lacunae. Even though anterior fusionof the attachments of the ring and the descending branches has not occurred, the lacunae are perforating the bands of thering and bifurcation of the septum progresses.

1015.

Loop ontogeny of Recent laqueid brachiopods

493

Michiko Saito

494

point is that no major discrepancy among species exist in therelative timing of loop development. The developmental
patterns of 'Frenulina' sp. is unusual because, as discussed
later, the adult individuals possess an annular loop, which istypical of juvenile individuals in other species.

Discussion
It is important to note that there is some ontogenetic
variation in the loop development within species. In
Frenulina sanguino/enta, for example, several specimens ofapproximately 4 mm length indicate four different loop
phases (Le. annular phase, haptoid phase, bilacunar phase,and bilateral phase). These similar-sized specimens differ
not only in their shape, thickness and size but also in thetiming of the modification of the ring and/or septum as
described by Richardson (1973a). One explanation for thisvariation may be that the growth speed vastly varies amongindividuals in this species. Gunji (1987) found three types ofloop structure within a single species Nipponithyris atra, andattributed this variation to the very wide deviation of growth
speed in N. atra. However, as the mode of absolute growth
has not been known for Frenulina sanguino/enta or for otherbrachiopod species, this hypothesis is yet to be tested.
Although the earliest loop phases are not presently known
in some species, it seems likely that all nine laqueid species
examined trace virtually the same early phases of loop
development, which are comparable to the loop development pattern for laqueids described by Richardson (1975).
However when looked at more closely, some differences
between taxa are apparent.
For example, anterior bifurcation of the septal pillar isobserved in some species but is not observed in otherspecies. Richardson (1975) suggested that in Dallinella
obso/eta, Fallax dallinitormis, Dallina septigera, and Laqueus
calitornianus, it is doubtful whether the septum bifurcatesanteriorly, because in these species the appearance ofsplitting could be confused with the anterior fusion of attachments of the ring and the descending branches (Le. haptoid
phase). However, in the species observed in this study, it isevident that the anterior split in the septum occurs before thegrowing (anterior) edges of the ring and the descending
branches fuse to form a haptoid loop. In Laqueus sp.,
specimens of the axial phase exhibit the anterior bifurcationof the median septum. The early anterior division of themedian septum also occurs in C. grayi and T. eoreanica, but
is not observed in the other species. In Pietothyris pieta,
Pietothyris sp., and F. sanguino/enta, by contrast, their haptoid
and bilacunar loop phases show a non-bifurcate median
septum projecting anteriorly between the divergent ascending and descending lamellae (Figures 2-2, 3-5, 5-6). This
indicates that in these three species the anterior fusion of
attachments of the ring and the descending branches
occurred without any anterior bifurcation of the septum, andthe loops of these species developed in a way different tothat of Laqueus sp., C. grayi, and T. eoreanica.
Another feature of interest is the disposition of the flanges
in the axial and cucullate phases. The direction of the
septal flanges is downward forward of the dorsal valve floor
in F. sanguino/enta, but lateral in the other species examined.
It may be worth pointing out that Laqueus and Frenulina were
included in the same subfamily Kingeninae by Richardson(1975) mainly based on the loop pattern of the adult phases.
However as mentioned before, Laqueus sp. and F. sanguino/enta differ in the early phases in such characters as
the presence or absence of bifurcation of the septal pillar
and the disposition of the septal flanges. The flanges in
Laqueus sp. are laterally directed but in F. sanguino/enta thedirection of the flanges is downward. These differences inthe early loop phase indicate the possibility that thesegenera are more distantly related than previously believed.
A comparison of the loop ontogeny of 'Frenulina' sp. fromoff Shimoda with the ontogenies of the other species reveals
that 'Frenulina' sp. resembles F. sanguino/enta externally, butdiffers significantly in adult loop pattern and mode of loop
development.
In young shells of 'Frenu/ina' sp., the valves are equallyconvex, and the lateral profile of the shell is rather flat,
however the shells become more convex with growth.
Specimens of 'Frenulina' sp. with a ventral valve larger than
5 mm in length exhibit the thickened convex form, and their
growth lines become crowded at the shell margins. Haradaand Mano (1960) investigated the metamorphosis of'Frenulina' sp. by breeding, and observed matured gonads inthe specimens with ventral valve length from 5 mm up to 7
mm. For the reasons given above, it is thus possible tostate that 'Frenulina' sp. attains the adult stage by the time aventral valve length of 5 mm has been reached.
Turning now to the loop patterns of 'Frenulina' sp., thisspecies seems to be already at an adult stage when it has

Figure 5. Frenulina sanguinolenta. 1: Specimen UMUT RB19847 (L=O.7 mm), ventral view. 2: Ventral view (L=1.0mm), specimen UMUT RB19848. Small septal pillar begins to emerge and the future cardinal process and the anteriorborders of the developing hinge plates are indicated by thickenings on the valve floor. 3: Specimen UMUT RB19849 (L=
1.3 mm), posterior view. Low socket ridges are seen. The direction of the flanges is downward. 4: Oblique view (L=2.2mm), specimen UMUT RB19850. The hood with septal flanges. 5: Specimen UMUT RB19851 (L=3.3 mm), showing
anteriorly spinous septal pillar and the ring. The crura and the descending branches extend. 6: Lateral view, specimen
UMUT RB19852 (L=4.3 mm). Lacunae are perforating the bands of the ring. Scale Bar=1 mm. 7: Specimen UMUT
RB19853 (L=4.4 mm) showing the anterior separation of the fused attachments and lacunae perforating the anterior anddorsal segments of the ring. 8: Lateral view, specimen UMUT RB19854 (L=6.6 mm). The adult loop.

1015. Loop ontogeny of Recent laqueid brachiopods

495

496

Michiko Saito

the loop at a stage which is seen only in juveniles in otherlaqueid species. The fact that there is no fossil record for'Frenulina' sp., while all the other genera examined except for
Frenulina are known from Neogene-Pleistocene deposits(Muir-Wood et aI., 1965) suggests that 'Frenulina' sp. is
probably a recently established species derived from anancestor with a 'normal' loop like that observed in other
Recent species. As figure 7 indicates, there is no major
variation in the size ranges of early loop developmental
phases amongst the examined species, but in 'Frenulina' sp.,loop development prematurely stops at the annular phase asa result of precocious sexual maturation. Viewed in thislight, 'Frenulina' sp. can be regarded as a paedomorphic
species that evolved by a process of progenesis (Alberch etal., 1979; McKinney and McNamara, 1991).
The pattern of early loop development in 'Frenulina' sp. hassome similarities with that of Pietothyris pieta, Pietothyris sp.,and Frenulina sanguinolenta in such features as the nonbifurcate septal pillar. Especially, the form of the median
septum of 'Frenulina' sp. is similar to that of Pietothyris sp.,
but the cardinalia resembles that of young phases of Laqueus sp. in some features such as morphology of the hinge
plates and absence of cardinal process. Although closeaffinity among 'Frenulina' sp., Pietothyris sp. and Laqueus sp.
is strongly suggested, the relationships among these three
species is an unsettled question.
It is interesting to consider the interspecific variations of
the loop in terms of developmental constraint as describedby Gunji (1987). He showed that in haptoid phase andphases later than bilacunar (Le. bilateral, latero-vertical,
trabecular, and teloform), loop transformation depends on thelocation of the 'loop center' and that interspecific variationsof the loop ontogeny may be explained by shifting of the'loop center'. It is, however, difficult to directly apply theconcept of developmental constraint to the early stages prior
to the haptoid phase, because the loop elements discussed
by Gunji (1987) are only seen in the late haptoid phase oflater. Although the factors responsible for the variations in

the early loop development are unknown, they should be
important in understanding loop ontogeny.
Differences and similarities in the early loop developmental
phases described herein demonstrate that they can be used
to assess general relationships at the generic level, but amuch more comprehensive study on both Recent and fossil
forms and on a number of congeneric species is required inorder to infer detailed relationships amongst laqueid brachiopods as a whole.

Summary
1. All the laqueid species examined appear to exhibit
roughly the same phases of loop development as thosedescribed by Richardson (1975). However some morphological differences are seen in the early phases of theloop development. Although Laqueus and Frenulina aresometimes included in the same subfamily mainly based on
the adult loop pattern, the early loop patterns of these two
species are rather different. This fact suggests that thesegenera may not be as closely related as previously considered by Richardson (1975).
2. The following early loop characters are considered
important in considering phylogenetic relationships of laqueid brachiopods: disposition of the septal flanges, presence or absence of bifurcation of the median septum, andthe timing of separation of fused ascending and descending
loop branches from the septal pillar.
3. Some intraspeCific variations are observed in therelative timing of loop development for example, in F. sanguino/enta
4. There is no major variation between the examined
species in the relative timing of loop development. However, the loop developmental pattern of 'Frenulina' sp. isunusual, suggesting a heterochronic relationship with otherspecies. It seems likely that 'Frenulina' sp. has been derived
from a process of progenesis.

Figure 6. 'Frenulina' sp. 1: A low non-fibrous septal pillar in specimen UMUT RB19855 (L=O.7 mm). 2: Obliqueview, specimen UMUT RB19856 (L=O.9 mm) with septal pillar and small septal flanges. 3: SpeCimen UMUT RB19857 (L=
1.5 mm), showing the ventral edge of the septal pillar and the extension of the flanges beginning to form a depression. 4:
SpeCimen UMUT RB19858 (L=1.9 mm). 5: Specimen UMUT RB19859 (L=2.4 mm), showing a ring with rudiments of theflanges. 6: Lateral view, specimen UMUT RB19860 (L=2.8 mm). 7: Specimen UMUT RB19861 (L=4.2 mm), oblique view.
The descending branches are not fused. 8: The adult stage loop with an incomplete ring and complete descending
branches (L=4.7 mm). Specimen UMUT RB19862.

1015.

Loop ontogeny of Recent laqueid brachiopods

497

Michiko Saito

498~ lLaQueus rubellusl __________=-._Bt0
ooc(oCi~ii....ii....iii.~iii!'!D..!!'iii_'!!ii!..!C)~~O....--.....___.__...__....__....__.....___..__....__.....__....__.....__...___...1.
Be ........-.-.-.........................-.-..............······-······························-0···············............................

4------------------1

2~-----------------------------------------------1

trO'~~~~~~~~~~
1LaQueus SP.I-

R~

F--.-----------------j

4 -.........-.-.......- ..-..-...-.....................-.·--·-0-···--··-08-·-·······-0-·························.........- ......- ..--..-..-..-.-....-.-.--.-...-..--.-..-.........-.-....-....
2 ············-····-·-··-·-·-···--·--··-··········-8····.......-.-..--...- ........-.-...............-..- ...- ..-.........--..-.......--.....-.-.-.-..- ......- ..--..-......-..- ....-.....
o ·······-·····-·-·-0-·-·········-···-···········-··-·-·...............- .......-.......- ....-...........................- .....-...........-..--...................-.-..---.......-.--.-.....................-....
~··\Pictothyris===

pietar-·····...···· . --....--.....-....-....-..................-......

Bt
Beo--.~C~O~_ _ _ _ _ _ _ _ _ _ _ _ _ __

~ 00

4

C

0

24------0~-~-=-------·-------------~~o~~~~==~======~
lPictothyris soJ..... ---.
~--

B

B~~----------~OO~O~acolDO--~------------~
4·~------~Q)~O~0~
2.4------~o----=~~---------------------------------i

Ol~~~~~~~~ebratalia coreaniea I
000 OCDDOIIX) ... ",Me. ·0
R~~------------~o-----------------~
4 .-.....-.--..--_.......--...-..........-..-...........·············-·O--·····p.··--·······················--·.-............-..-.....-..-...........-.-.----...-.-.-.-..- .•....................•.
2~_ _ _ _ _ _ _ _ ~0_. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.-1o0~ ]'Frenulina' so.l
Bt

Be;-----------~O~~~=m=)~aD~O~-----------------i
4i1-----------~~~~~~~~----------------------__i20== ~~~-~~~O---------------------_1

0

0- .....- ......-.-.....- ......- ..-.-...................-.....................- .....-.....-..........- ..............--..- .............-...-._..-.-........-.......--..-.......----..-..-..-..--.-......

~: )Jolonica nipponica I ...._.__ ....__.._..._.._.._........._..__._.....______._.__.__._._..__._..__..__._.._._.__.__--.. . ---.. . .-.. . . -..-..-..-.. . . -..-.-.. . . . -···--·-·-·······--·-····-··-0·······-···-0-·..··-0-0-··-0-·-········--·-··-·-..-----·-··..·-·-·-·---..4.;-----------------------------------------iR~-

2- .-.._ . - -...-.-.......---..-...-.-.-..-...--.._--.---...- ..- -.............- -..- ..-.-.-.-.--.-.-..-.-.-..- - - -...---.--.

011=~~~;~1====~==~=;=;~~~,======;===~~~~~~
0.4

1

10

100

Length of Dorsal Valve (mm)Figure 7. Size of each loop developmental phase plotted for the examined laqueid species. Each point indicates an individual
specimen with the phase of loop development indicated. The right end of the plot for each species corresponds to the speCimen of
the maximum shell length so far collected for each species. Abbreviations in the vertical axis: Pb=Prebrachidial phase, Axe = Axial
phase (early), AxI=Axial phase (late), Cu=Cuculiate phase, An=Annular phase, Hp=Haptoid phase, Bc=Bilacunar phase, Bt=
Bilateral phase, Lv=Latero-vertical phase, Tb=Trabecular phase, Te=Teloform phase.

1015.

Loop ontogeny of Recent laqueid brachiopods

Acknowledgments
The author wishes to thank Dr. K. Endo (University ofTokyo) for critical reading of the first draft, and Prof. K.
Tanabe, Dr. T. Oji (University of Tokyo) for their helpfuladvice. I wish to thank Dr. M. Arita (Geological Survey ofJapan), Mr. H. Fukuda (Tokyo Metropolitan University), Mr. T.
Miyauchi (Wakkanai City), Prof. S. Ohta and Mr. E. Tsuchida(Ocean Research Institute, University of Tokyo) for their help
in collecting samples, and Dr. 0.1. MacKinnon of University ofCanterbury, New Zealand for advice on techniques of sample
preparation and providing me with important suggestions.
This study was supported by a grant from the Fujiwara
Natural History Foundation.

References citedAlberch, P., Gould, S.J., Oster, G.F. and Wake, D.B., 1979:
Size and shape in ontogeny and phylogeny. Paleobiology, vol. 5, no. 3, p. 296-317.
Atkins, D., 1959: The growth stages of the lophophore andloop of the brachiopod Terebratalia transversa (Sowerby). Journal of Morphology, vol. 105, no. 3, p. 401-426.
Gunji, Y., 1987: Metamorphosis of the loop in Cenozoic
dallinacean brachiopods and its developmental constraint. Lethaia, vol. 20, p.239-255.
Hatai, K.M. 1938: A note on a Cenozoic Brachiopoda,
Coptothyris grayi (Davidson). Jubilee Publication in theCommemoration of Prof. H. Yabe, M.I.A. 60th Birthday,vol. 1, p. 99-118,1 pI. Tokyo.
Hatai, K. 1940: The Cenozoic Brachiopoda from Japan.
Science Reports of the Tohoku Imperial University,
Second Series (Geology), vol. 20, p.1-413, pis. H2.
Harada, I. and Mano, R., 1960: Frenulina sanguinolenta(Gmelin), a brachiopod, found in the southern coast of499

the Izu Peninsula. Collecting and Breeding, vol. 22, p.
37 -40. (in Japanese).
Konjukova, E.D., 1948: The post-embryonic development of
the shell and of the brachial apparatus of certain Pacificbrachiopods. Bulletin of Academic Science of U.S.S.R.
(Biol.), vol. 2, p. 213-224. (in Russian).
Konjukova, E.D., 1957: Brachiopods of Far Eastern seas.
Researches Concerning the Far Eastern Seas of the
U.S.S.R., vol. 4, p. 5-84. (in Russian).
Mackay, S., MacKinnon, 0.1. and Williams, A., 1994: Ultrastructure of the loop of terebratulide brachiopods.
Lethaia, vol. 26, p. 367 -378.
MacKinney, M.L. and McNamara, K.J., 1991 : Heterochrony(the evolution of ontogeny). 437 pp. Plenum Press, NewYork.
MacKinnon, 0.1., 1993: Loop ontogeny and ultrastructure inbrachiopods of the family Terebratellidae. In, Kobayashi, I., Mutvei, H. and Sahni, A. ed., Structure, Formationand Evolution of Fossil Hard Tissues, p.31-40. Tokai
University Press, Tokyo.
Muir-Wood, H.M., Elliott, G.F. and Hatai, K., 1965: Mesozoic
and Cenozoic Terebratellidina. In, Moore, R.C. ed.,Treatise on Invertebrate Paleontology, Part H, p.816857. Geological Society of America and the Universityof Kansas Press.
Richardson, J.R., 1973a: The loop development of thebrachiopod Frenulina sanguinolenta (Gmelin 1790).
Proceedings of the Royal Society of Victoria, vol. 86, p.
11H16.
Richardson, J.R., 1973b: Studies on Australian brachiopods.
The family Laqueidae (Terebratellidae). Proceedingsof The Royal Society of Victoria, vol. 86, p.117-125.
Richardson, J.R. 1975: Loop development and the classification of terebratellacean brachiopods. Palaeontology,
vol. 18, p. 285-314.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp. 500-521, 8 Figs., September 30, 1996
© by the Palaeontological Society of Japan 1996

Miocene decapod crustacea from the Chichibu
Basin, Central JapanHISAVOSHI KATO
Natural History Museum and Institute, Chiba, 955-2, Aoba-cho,' Chiba, 260 Japan

Received 17 July 1995; Revised manuscript accepted 14 May 1996
Abstract. Seventeen fossil decapods are described from the Miocene of the Chichibu Basin, Saitama
Prefecture, Central Japan. The decapods occur in the Ushikubitoge Formation, Nagura Formation andYokoze Formation. The following five are new: Trachycarcinus inflatus, Cancer sakamotoi, Itoigawaia
chichibuensis, Maja mori;, Miosesarma nagurense. Six decapod assemblages are recognized in thebasin. The fauna is characterized by the predominance of muddy bottom inhabitants of the lower
sublittoral zone, represented by the Miosesarma nagurense sp. nov. assemblage from the Nagura
Formation. The occurrence of Maja morii sp. nov. is the first fossil record of the genus from the northern
Pacific region.
Key words: Miocene, Crustacea, Decapoda, new species, Chichibu Basin, decapod assemblage.
Introduction

Tertiary strata of the Chichibu Basin have been studied indetail for over 60 years (Hayakawa, 1930; Watanabe et al.,1950; Ijiri et al., 1950; Arai, 1960; Kanno, 1960; Hyodo,
1986; Latt, 1990; Takahashi, 1992, etc.). It is well known
that they yield numerous crabs. These fossil decapods,
however, have never been described and studied up to thepresent, although many other fossil groups have been studied in detail.
Recently, 120 species of decapod crustacean fossils were
described from the Cenozoic of Southwest Japan and theirfaunal changes in relation to climatic change were discussed (Karasawa, 1993). Nevertheless, knowledge of thedecapod fauna from the Cenozoic of Northeast Japan is still
fragmentary, with several records by Nagao (1932, 1941, etc.),
Imaizumi (1951, 1958a, 1958b, 1961, 1962, etc.), Takeda andFujiyama (1984) and Takeda et al. (1984).
The present study presents one of the faunal aspects of
the Miocene fossil decapod assemblages from Northeast
Japan.

ment rocks. It consists of a basal conglomerate and sandstone with inliers of the Tomita Siltstone Member and the
Nenokami Sandstone Member. Decapod fossils were foundin the loose sandy siltstone immediately above the basal
conglomerate of the Ushikubitoge Formation distributed in~ ~hiChib~
JV
c~ (
+
()

~

Tokyo

Basin

.
-

36

,,,.,~

General outline of geology in the study area

Tertiary deposits in the Chichibu Basin are distributed in
an area about 15 km from east to west and 12 km from northto south (Figures 1,3). The three major stratigraphic units of
the Tertiary established by Arai (1960) and Kanno (1960) are
the Ushikubitoge Formation, Oganomachi Group and the
Chichibumachi Group, in ascending order (Figure 2). All ofthem are marine depOSits.
The Ushikubitoge Formation unconformably overlies base-oI

Figure 1.

5

I

10 K

I

m

Map showing location of the study area.

_'* I

Terrace deposits

Thickness

0..

;:::I

e
OF'
:.a Yokoze onnatIOn~

5B

I-=-:::::-::-=-=-=-=-:::::-=_~

I 2000m+

E
;:::I

.0

~

:.au

9

e

91
~

o·
o

CD
Q.I

c

.

Q.I
u
o

Nagura FonnatIOn

N8:;

I-L-_-":::"~":"~_~':z;;;·,·~v;~.
I--------~~~

620m

m

::J

CD

poorly sorted conglomerate,
tal us breccia
tuff

~
0)

~I

I §- I Ogano Fonnation
e

o

:.a

~

E
o
§
OJ)

o
~

;>,1
~

1

CN3-4
NN4-5

/'
MiyatoFonnation-- - - -

IS

~

1600m

~

iii

alternating beds of sandstoneand sil tstonealternating beds of siltstoneand sandstoneII

medium- to fine grainedsandstone~~siltstone, mudstoneIIcoarse grained sandstone~

conglomerate

~

CD

o

III

"0

8.
(J)

sandy siltstone

~

0..

a3
o

:::r
o·
:::r
B'

c
OJ

IIIs·

Cretaceous Sanchu Graben
Chichibu System(Paleozoic and Mesozoic)*
Takahashi,
1992

Figure 2.

*****

Takahashi Hyodo,
et ai., 1989
1986

Synthetic stratigraphy and columnar section of Miocene formations of the Chichibu Basin.

Arrows indicate decapod fossil bearing horizons.

v.

o

502

Hisayoshi Kato

the northwestern part of the basin and in the Nenokami
Sandstone Member extending into the northeastern part ofthe basin. The Tomita Siltstone Member yields many
molluscan fossils, but no decapod fossils. According to~Yokoze Fonnation~

Nagura Formation

~
..c:
U

Co

Kanno (1960), the main part of the Ushikubitoge Formation
was deposited in a shallow marine environment. The
Nenokami Sandstone Member was deposited in shallow,
warm to temperate water. Kanno described the molluscan

N

Ogano Formation

~

E :::

00
c:

o""

Miyato Fonnation

OJ)

Nenokami Sandstone
MemberTomita Siltstone
Membermain partUs

Yoshidagawa . - . - - River

Arakawa
River __

Yz-4
Yz-s
Yz-6

Yokozegawa
River

o

4 km

=-====--===--==--

Figure 3.

Map showing decapod fossil localities on the geological map of the study area.

1015.

Miocene decapods from Chichibu Basinassemblage of the Tomita Siltstone Member and inferred
depths greater than 200 m. The microfossil evidence
however, suggests an inner neritic environment (Ujiie andlijima, 1959; Takahashi, 1992).
The Oganomachi Group conformably overlies the Ushikubitoge Formation. It is characterized by thick turbidite
sediments, consisting mainly of alternating beds of siltstoneand sandstone that were deposited in bathyal environments(Takahashi, 1992). Megafossils are very scarce in thisgroup, and decapod fossils were not obtained.
The Chichibumachi Group comprises the Nagura andYokoze Formations. The Nagura Formation is dominated byfossiliferous, gray to light gray, massive to weakly bedded
sandy siltstone which was deposited in a shallow-water
environment (Kanno, 1960; Latt, 1990; Takahashi, 1992).
Molluscan fossils are common in this formation and abundant decapod fossils occurred in the middle to upper part
(Figure 2). The uppermost part of this formation is boundedby whitish tuff beds (Tadenuma Tuff Beds' in Hyodo, 1986).
The overlying Yokoze Formation is composed of massive
sandy siltstone and coarse-grained marginal deposits of thesedimentary basin, such as poorly sorted conglomerate andtalus breccia. This formation locally contains abundantmolluscs and occasional decapod fossils. Although it is
widely accepted that the molluscs from the coarse-grained
sediments indicate a rocky or sandy bottom of warm, shallow
water, the depositional environment of the uniform sandy
siltstone distributed in the central part of the basin is still
controversial. A deeper environment (Kanno, 1960), a
semipelagic basin plain (Latt, 1990), and a shallow, inner
sublittoral environment (Takahashi, 1992) have all beensuggested.
In general, the sediments of the Oganomachi Group
become coarser towards the southern border, intercalating a
number of conglomerate layers. In contrast, those of the
Chichibumachi Group becomes coarser either towards thesouthern and eastern border, intercalating numerous thickconglomerate layers.
The geologic age of these strata is given in Figure 2.
Takahashi (1992) showed that the planktonic foraminifera
obtained from throughout the Tertiary of the basin indicate
zone N. 8 of Blow (1969). According to Takahashi et al.
(1989), the calcareous nannofossils from the Ushikubitoge
and Miyato Formations indicate zones CN 3-4 of Okada andBukry (1980) or NN 4-5 of Martini (1971). Hyodo (1986) andHyodo and Niitsuma (1986) suggested that the normal polarity
observed in the upper part of the Oganomachi and Chichibumachi Groups is correlated with the ocean magnetic
anomaly 5B.
The total thickness of the Tertiary sequences in this region
attains a maximum of more than 5,000 meters. The thickness of each formation is given in Figure 2.
Decapod fossil preservation
The occurrence of decapod fossils in the Chichibu Basinmay be placed into three categories. 1) Decapods that arepreserved in nodules thought to represent burrows. Many
Upogebia sp. specimens were preserved in this condition.

5032) Decapods sporadically buried in sandy siltstone free of
calcareous nodules or concretions. Many crabs arearticulated, indeed, most crabs from the basin are preservedin this condition. They are more or less depressed, andsome crabs are preserved in the open molt position (Schafer,
1951; Bishop,1986a). Since even these fragile exuviae are
more or less articulated, these crabs may be autochthonous.
3) Crabs as disarticulated or fragmentary remains. Thismode of occurrence was frequently observed in coarsegrained sediment (weakly consolidated sandy siltstone andconglomerate) of the Yokoze Formation.
Decapod assemblages
About 800 fossil decapods were collected from 33 localities which are listed in Table 1. Six decapod assemblages
can be recognized on the basis of dominant species. Thisfaunal analysis based on the characteristic species reveals
the presence of two different decapod assemblages even in
the sandy siltstone of the Nagura Formation; they are similar
in appearance.

1. Upogebia sp. assemblage
This assemblage is defined by the predominance of
Upogebia sp. which often shows in situ preservation.
Upogebia sp. was commonly found in cemented burrows.
Some carapaces were found retaining those abdominal parts
which are very fragile and easily detached after death.
Most of the Japanese living and fossil species of Upogebia
are known from intertidal to sublittoral environments (Sakai,
1982; Karasawa, 1993). This assemblage was observed
only in the basal part of the Ushikubitoge Formation, andconfirms the conditions of the lower part of this formation
described by Kanno (1960) from the molluscan evidence as
those of 'the Shirasu Sandstone Member'.
Co-occurring molluscan fossils: Nucula sp., Lucinoma sp.,
Acila sp., Macoma sp., Mya sp., Orectospira ? sp., and Thracia
sp.
Locality and horizon : Us (basal part of the Ushikubitoge
Formation).
2.

Carcinoplax antiqua assemblage
The Carcinoplax antiqua assemblage is defined by theabundance of C. antiqua. This assemblage is recognized in
the Nenokami Sandstone Member and Nagura Formation.
However, the modes of occurrences are slightly different
between the two horizons. In the Nenokami Sandstone
Member this assemblage includes Munida sp. which isconsidered to be a relatively deeper water taxon, and isassociated with relatively diversified molluscs. On thecontrary, in the Nagura Formation this assemblage yields lessdiversified molluscan and co-occurring decapod taxa. The
Carcinoplax antiqua assemblage is here considered a sandy
bottom assemblage of the lower sublittoral zone on the basisof the molluscan evidence by Kanno (1960; 1980) and thepresent study.
Co-occurring molluscan fossils: Acila sp., Saccel/a sp.,
Modiolus? sp. Felaniel/a sp., Chlamys sp., Mizuhopectenchichibuensis, Venericardia (Cyclocardia) pacifera, Macoma

v.

l2

Table 1. List of fossil decapods from the Chichibu Basin.
Ushikubitoge Formation.

Locality numbers correspond to those in Figure 3.

Us: main part of the

Total number of specimens
Formation

Us

Nenokami Sandstone
Member (Nk)

~~

Us

2

Upogebia sp.

I

4

3

4

18

12

8

13

9

21

6

14

IO

3

IS

20

16

17

II

7

I

19

5

2

1

4

3

7

10

5

1

2

Mursia tak4hashii hnaizurni

8

2

Trachycarcinus inflatus n. sp.

38

2

1

1

4

sp.2

Munida sp. cf. M. nishioi

Cancer sakamotoi n. sp.

10

1

?

23

sp.

6
1

1

:::r::

i

2

1

1

14

1

1

3

?

2

4
2

i

3

2

Itoigawaia chichibuensis n. sp.

II

Minohellenus? sp.

12

2

2

3

?

?
2

2

Medoeus? sp.
Carcinop/ax antiquo Ristori

C.

5

6

7

Callianopsis sp. 1

C.

2

\3

Eucal/iax sp.

C.

Yokoze Fonnation (Yz)

Nagura Formation (Ng)

25

3

?

1

17

17

1

sp.

1

16

7

2

4

?

5

2

8

1

1

1

Typhlocarcinodes? sp.

1
2

Xanthoidea fam. gen. et sp. indeL

Maja morii n. sp.
Miosesarma nagurense n. sp.

Tolal number of specimens

1

9

1

4

27

184 5

1

9

10

101

10

4

1

10

1

3

3

2

1

3

3

1015.

Miocene decapods from Chichibu Basinsp., Cultel/us izumoensis, Turritel/a sp. Tectonatica sp.,
Galeodea sp. and Dentalium sp.
Locality and horizon: Nk-1,2 (Nenokami Sandstone Member of the Ushikubitoge Formation); Ng-5, 19 (Nagura Formation).

3. Miosesarma nagurense sp. nov. assemblage
This assemblage is defined by the predominance of
Miosesarma nagurense sp. nov. and contains Carcinoplax
antiqua and Mursia takahashii. At several localities the
Nagura Formation yields abundant M. nagurense having wide
ranges of carapace width (e.g. 6 mm-27 mm at Ng-13).
These facts and the mode of preservation indicate that theassemblage may be autochthonous or nearly so. Considering the evidence of microfossils by Takahashi (1992) andmolluscan fossils in this study, the environment of thisassemblage is supposed to be a muddy bottom setting in the
inner sublittoral zone. This interpretation corresponds to thefact that the Miosesarma japonicum-C. antiqua assemblage
in the late Early Miocene of southwestern Japan is considered to be comprised of sandy or muddy inhabitants of thelower sublittoral zone (Karasawa, 1993).
Co-occurring molluscan fossils: Acila sp., Portlandia sp.,
Yoldia rhombica and Cultel/us izumoensis.
Locality and horizon: Ng-13, 6,10,14.
4.

Trachycarcinus inflatus sp. nov. assemblage
This assemblage is composed mainly of Trachycarcinus
in flatus sp. nov., Cancer sakamotoi sp. nov., M. takahashii,
Itoigawaia chichibuensis sp. nov. and Callianopsis sp. 1, andcontains Munida sp. and Eucal/iax sp. It is characterized by
the absence of Miosesarma nagurense sp. nov. and C.
antiqua, and shows apparently high species diversity incomparison with the other assemblages in the basin. At
locality Ng-4, this assemblage is accompanied by abundantmolluscan fossils, including conjoined valves of the large
pectinid Mizuhopecten kimurai. Therefore, this assemblage
indicates a sublittoral environment. The microfossils of
Takahashi (1992) and the molluscan fossils of the present
study, however, suggest a slightly deeper environment than
the former two assemblages. Despite the absence of T.
inflatus, Ng-18 has a similar species composition.
Co-occurring molluscan fossils: Acila sp., Portlandia
watasei, Lucinoma sp., Mizuhopecten kimurai, Cultel/us
izumoensis, Periploma sp. and Apol/on yabei.
Locality and horizon: Ng-4 (Nagura Formation).
5.

Xanthidae assemblage
Xanthid crabs, comparable with Medaeus, occurred inloose silty sandstone of the upper part of the Yokoze
Formation (Yz-6). This formation, exposed near the southern and eastern borders of the basin, intercalates a numberof conglomerate beds and talus breccia that occasionallycontain abundant rocky shore molluscs and hermatypiccorals. These conglomerates rarely contain poorly preserved dactyli and fixed fingers of xanthid crabs. At YZ-6, a few
meters above and below the decapod horizon are intercalated cobble to granule conglomerate beds which containabundant rocky shore gastropods such as Turbo sp. and505

Conus sp. This assemblage is characterized by the
epibionts on the rocky shore or sandy bottom in the marginal
area of the basin.
Co-occurring molluscan fossils (Yz-6): Concochele disjuncta, Lucinoma sp., and Cuspidaria sp.
Locality and horizon: Yz-5,6 (yokoze Formation).

6.

Callianopsis spp. assemblage
In contrast with marginal coarse sediments, the thick andmonotonous sandy siltstone of the Yokoze Formation
exposed in the central part of the basin yields frequent
Callianopsis spp. in association with fossil burrows. Therefore this assemblage consists of autochthonous endobionts
of muddy bottoms in the central part of the basin.
Co-occurring molluscan fossils: Solemya sp., Portlandia
sp., Lucinoma sp., and Periploma sp.
Locality and horizon: Yz-4 (yokoze Formation).
Discussion

The decapod fauna in the Chichibu Basin is represented
by the predominance of muddy bottom inhabitants in shallow
water environments as a whole. Recognition of six
decapod assemblages signifies relatively high diversity of thefauna, considering that most of the decapods occurred inlimited lithofacies (mainly sandy siltstone). While many ofthe decapod genera also occur in the Lower to Middle
Miocene of Southwest Japan (11 out of 15 genera in Karasawa, 1993), the fauna shows less similarity on the species
level (only 2 out of the 17 species). Tropical species reported from the early Middle Miocene of Southwest Japan, e.g.
Ozius collinsi (Karasawa, 1992), Thalassina anomala (Karasawa and Nishikawa, 1991), Euryozius spp. (Karasawa, 1993)
and Daira perlata (Karasawa, 1993), were not found in thebasin studied, nor was Scylla ozawai Glaessner, 1933, which
was a subtropical-tropical species described from theKadonosawa Formation in Iwate Prefecture and several
localities in Southwest Japan.
The most characteristic feature of the decapod assemblages from the Chichibu Basin is that almost all the specimens occurred in limited lithologic facies of limited stratigraphic horizons (Nenokami Sandstone Member and Nagura
Formation; Table 2). At some localities (Ng-10, 13) the
Nagura Formation yielded very abundant Miosesarma nagurense, occasionally exceeding in number the associatedmolluscs. Bishop (1986b) discussed such decapoddominated assemblages, and classified the mode of occurrences of decapods into 1) uncommon remains in molluscan
fossil assemblages, 2) common remains in molluscandominated fossil assemblages and 3) dominant elements in
decapod assemblages (e.g. the Upper Cretaceous Dakoticancer Assemblage by Bishop, 1986a; 1986b, etc., which isconsidered to have been caused by optimal conditions forthe crab).
The predominance of Miosesarma in the Chichibu Basinmay represent a similar mode of occurrence to the Dakoticancer Assemblage with respect to the numerical dominance of crabs over molluscs. Since the Dakoticancer
Assemblage is found in quite limited stratigraphic horizons

Hisayoshi Kato

506

Table 2. Stratigraphic distributions and dominant decapod species of each formation.
No. ofmaterials % Life Mode Bottom character

Formation

No. of specie~
and material

Yokoze F.

8(19)Miosesarma nagurense n. sp. 6
4
Callianopsis sp. 2

32
21

13(650)Miosesarma nagurense n. sp. 368
81
Carcinopiax antiqua
Trachycarcinus inflatus n. sp. 44
Mursia takahashii
35

epibenthos
57
12 epibenthos
6.4 epibenthos
5.8 epibenthos

silty sandsilty sand-medium sandsilty sandsilty sand11
iosesarma nagurense n. sp. 9

56
22
20

epibenthos
epibenthos
epibenthos

silty sand-fine sandsilty sand-medium sandsilty sand-fine sand13

92

endobenthos

sandy silt

Nagura F.

Dominant species

epibenthos
endobenthos

silty sandsilty sand

Ogano F.
Miyato F.
\

Nenokami Ss. M.
\ Tomita Silts. M

Ushikubitoge F.

1\

Carcinopiax antiqua

5(45)
2(13)

~nidaSP'

30'Upogebia sp.

(3 m to 7 m thick) over widespread areas (15 km2 to 1,500 km2)
and occurs repeatedly, it is probable that this pattern represents periodic blossomings of the oppotunistic decapod
species in consequence of the change of the environmental
conditions, as noted by Bishop (1986b). On the other hand,the stratigraphic horizons of the Miosesarma nagurense sp.
nov. assemblage are not so limited and the lateral extensionof the distribution of the assemblage is not clear.
The density of decapod crabs in the Chichibu Basin is not
great as compared to recent submarine decapod communities (e.g. Thorson, 1957). Therefore, the abundance of thedecapod fossils in the basin may have been due to sedimentary conditions which by chance favored their preservation.
Some other decapod-dominant assemblages in Japan thatare mainly composed of endobiont Thalassinidea 'shrimps'
remain to be studied.
Acknowledgments
I wish to express my sincere gratitude to Professor Kei
Mori of the Institute of Geoenvironmental Science, Graduate
School of Science, Tohoku University, for helpful suggestions, continuous encouragement throughout this study, andcritical reading of the manuscript. Deep gratitude is also
expressed to Professor Rodney M. Feldmann and Ms. Carrie
Schweitzer-Hopkins of Kent State University, Ohio and Dr.
Joe S.H. Collins of London for their critical reading of themanuscript and many useful comments. I wish to express
my hearty thanks to Professors Tsunemasa Saito andKunihiro Ishizaki of Tohoku University for their useful suggestions and encouragement. I wish to thank Mr. Osamu
Sakamoto of the Saitama Museum of Natural History forsupporting the field survey and providing valuable comments.
Thanks are also due to Dr. Hiroaki Karasawa of the
Mizunami Fossil Museum, Dr. Masatsune Takeda of the

National Science Museum, and Drs. Akira Asakura andTomoyuki Komai of Natural History Museum and Institute,
Chiba for valuable suggestions regarding the systematic
placements of several decapod taxa. Sincere thanks arealso due to Drs. Masanori Shimamoto and Yoshikazu Nodaof Tohoku University, and Dr. Masaki Takahashi of theGeological Survey of Japan. The author is much indebted
to Mr. Yuji Takakuwa of the Gunma Museum of Natural
History, Mr. Kiyohiko Ogai, Kazo City and Mr. Yoshiaki
Mizuno, Nagoya City, for assistance in collecting and loan of
specimens.

Systematic descriptions
The described and figured specimens are deposited in thecollection of the Institute of Geology and Paleontology,
Faculty of SCience, Tohoku University, Sendai, 980-77
Japan (IGPS coil. cat. no. 102438-102442, 102713-103102).
Order Decapoda
Infraorder Thalassinidea Latreille, 1831
Superfamily Callianassoidea Dana, 1852
Family Upogebiidae Borradaile, 1903
Genus Upogebia Leach, 1814

Type species.-By monotypy Cancer stellatus Montagu,
1808 (ICZN Opinion 434).
Geologic range.-Cretaceous? to Recent.
Upogebia sp.
Figures 4-1a-3b

Material.-IGPS coil. cat. no. 102438-102443.
Occurrence.-Ushikubitoge Formation.
Oescription.-Carapace with trilobed front. Rostrum tri-

1015.

Miocene decapods from Chichibu Basin

angular with an obtuse apex; two or three series of granules
and a narrow median furrow. Lateral longitudinal ridge
tuberculated and broadened in anterior part; gradually
becoming narrower in posterior part. Lateral longitudinalgroove deep in anterior part; slightly divergent backward.
Cervical groove distinct. Posterior thoracic region with arow of granules along cervical groove in lateral part of dorsal
surface and lateral surface.
First and 2nd abdominal somites longer than 3rd-6th
somites.
First legs subchelate, equal in size and shape. Inner andouter surfaces of manus moderately swollen, rectangular inoutline. Proximal and upper margins of inner surface fringed by row of granules. Outer surface of manus irregularly
granulated; granules dense in lower half, clustered to form
wrinkles. Fixed finger small, acutely triangular in lateralview, but dentition unknown. Carpus rectangular in upper
view, outer surface with two shallow longitudinal grooves.
Remarks.- The present species is similar to the Recent
Upogebia major (De Haan, 1839) from Japan in the featuresof the rostrum and propodus of the first leg, but detailed
comparison between the two is difficult, because of theabsence of the dactylus of the first leg.
Family Callianassidae Dana, 1852
Subfamily Eucalliinae Manning and Felder, 1991
Genus Eucalliax Manning and Felder, 1991
Type species.-By original designation Callianassa quadracuta Biffar, 1970.
Geologic Range.-Eocene to Recent.

Eucalliax sp.
Figures 4-4a, bMaterial.-IGPS coil. cat. no. 102713-102717.
Occurrence.-Nagura Formation.
Description.-Slightly smaller right chela with acute, long
fixed finger. Manus of right chela short; lower part of outersurface bearing clusters of tubercles; lower margin fringed
by granules; lower proximal margin moderately archedoutward. Fixed finger slightly shorter than manus, moderately curved upward; inner surface with broad, longitudinal
depression and two or three granules on basal part.
Larger left chela stubby with short fixed finger. Distal partof outer surface of manus divided into upper thickened
angle, middle part and base of fixed finger. Fixed finger
about half as long as manus. Dactylus strongly bent downward; a strong, longitudinal keel on outer surface and large
tubercles above keel.
Remarks.- The chelae of the present species resemble
the larger chelae of CalJianopsis spp. However, it is distinguishable from Callianopsis spp. by the absence of a large,
triangular tooth on the proximal part of the fixed finger, andhaving a remarkably small fixed finger on the left chela.
The present species is easily distinguished from Eucalliax
miyazakiensis Karasawa, 1993 from the Pliocene MiyazakiGroup which have chelae that are nearly equal in shape with507

very short fixed finger.
Family Ctenochelidae Manning and Felder, 1991
Subfamily Callianopsinae Manning and Felder, 1991
Genus Callianopsis De Saint Laurent, 1973
Type species.-By monotypy Callianassa goniophthalma
Rathbun, 1902.
Geologic range.-Eocene to Recent.

Callianopsis sp. 1
Figures 4-5, 6Material.-IGPS coil. cat. no. 102721-102729.
Occurrences.-Nagura Formation; Yokoze Formation
Description.-Manus of larger cheliped rectangular inlateral view, slightly longer than high; lower part of outersurface with dense mammillated tubercles near base of fixed
finger; inner surface with longitudinal depression at base of
fixed finger. Fixed finger gently curved upward; outersurface with a rim bearing two small socket-like projections
directed distally, along prehensile margin. Prehensile edge
slightly flattened with large triangular tooth on proximal, andsubconical tooth near longitudinal midpoint. Dactylus stout,
about two-thirds length of manus; slightly longer than fixed
finger; upper margin bearing two or three tubercles near
proximal articulation. Strong keel in middle part of outersurface extending longitudinally; several tubercles arranged
on keel proximally. Two or three small socket-shaped
tubercles above, and three or four similar ones below keel.
Inner surface with a longitudinal keel; lower part bearing
broad, longitudinal depression and several small tubercles
clustered near proximal articulation. Carpus rectangular;
about one-third as long as, and slightly narrower thanmanus; lower distal angle slightly indented inward. Merus
one and a half times as long as carpus, outer surface
flattened, with two medial, longitudinal ridges. Ischium
slender with fringed lower margin.
Smaller cheliped slender, elongate; about half as long aslarger one. Fixed finger broader than dactylus with shallOWlongitudinal depression on inner surface; sporadical pits
arranged longitudinally on lower margin. Dactylus roundedin cross section, with deep longitudinal groove and several
pits on inner surface.
Remarks.- The chelipeds of the present species are
similar to that of Callianopsis muratai (Nagao, 1932) from theUpper Eocene Poronai Group, in general proportions and inhaving a triangular tooth near the base of the fixed finger ofthe larger cheliped. The present species is, however, clearly distinguished from C. muratai by exhibiting a more tuberculated outer surface on the manus and having a weakly
developed dactylus which is shorter than the manus.

Callianopsis sp. 2
Figures 4-7,8Material.-IGPS coil. cat. no. 102730-102733.
Occurrence.- Yokoze Formation.

Hisayoshi Kato

508

Description.-Manus nearly quadrate; slightly broader
than long. Lower part of outer surface bearing conicaltubercles of various sizes near base of fixed finger. Several
tubercles also exist near base of dactylus, some of whichcluster to form irregular pustules. Fixed finger about twothirds length of manus; stout with a blunt apex and oval incross section; lower margin strongly curved upward andslightly curved inward. Prehensile edge flattened; subconical, weakly vaulted tooth on it slightly proximal to
mid length. Two or three pits on a longitudinal rim alongprehensile margin and several small pits along lower margin.
Dactylus slightly longer than fixed finger; strongly turned
downward; a strong ridge, with three or four socket-like,flattened tubercles above, extending along midpart of outersurface. Conical tubercles developed on outer surface
around articulation; fused into large pustules.
Remarks.- This species resembles Callianopsis sp.1 in the
tuberculation on the outer surface of the manus and inhaving a longitudinal ridge with socket-like tubercles on theouter surface of the dactylus. However, Callianopsis sp. 2 iseasily distinguishable from C. sp.1 in having irregularly
developed large pustules and a thick, strongly curved fixed
finger.

Infraorder Anomala Boas, 1880
Superfamily Galatheoidea Samouelle, 1819
Family Galatheidae Samouelle, 1819
Subfamily Galatheinae Samouelle, 1819
Genus Munida Leach, 1820

spine directed forward at anterolateral angle. Hepatic
region with a broadly triangular lateral spine. Epibranchialregion with three lateral spines. An acute spine at posterolateral corner of gastric region.
Chelipeds oblong, slender, tuberculated. Propodus
densely covered with asymmetrical tubercles directed distally.
Remarks.-Munida sp. most closely resembles M. nishioi
Karasawa, 1993 from the Middle Miocene Yatsuo Group in
the general shape and dorsal striations of the carapace.
However, the present species is slightly different from M.
nishioi in having densely tuberculated chelipeds. The rostrum is not preserved in any specimens obtained up to now.
Since the precise comparisons and exact determination
require the rostrum and spines on the anterior part of thecarapace, the definite identification may have to be reserved.
Infraorder Brachyura Latreille, 1803
Section Heterotremata Guinot, 1977
Superfamily Calappoidea De Haan, 1833
Family Calappidae De Haan, 1833
Subfamily Calappinae De Haan, 1833
Genus Mursia Desmarest, 1823
Type species.-By monotypy Mursia cristiata H. Milne
Edwards, 1837.
Geologic range.-Oligocene to Recent.
Mursia takahashii Imaizumi, 1952

Figures 4-10--13
Type species.-By monotypy Pagurus rugosus Fabricius,1775 (ICZN Opinion 712).
Geologic Range.-Paleocene to Recent.

Mursia takahashii Imaizumi, 1952, p.88-95, figs. 1-4; 1958b, p.
309, figs. 1-3; 1959, p. 15-21, fig. 6; Sakumoto et aI, 1992, p.

Munida sp. cf. M. nishioi Karasawa, 1993

Material.-IGPS coil. cat. no. 102757-102780.
Occurrences.-Nagura Formation; Yokoze Formation.

Figure 4-9
Material.-IGPS coil. cat. no. 102744-102756.
Occurrences.-Nenokami Sandstone Member; Nagura
Formation.
Description.-Carapace, excluding rostrum, slightly longer
than broad; narrowing both anteriorly and posteriorly.
Orbitofrontal margin strongly arched forward. Dorsal surface of carapace rugose. Rostrum, spine missing, withnarrow base. Supraorbital spine separated clearly fromrostral spine at the base. Small median spine on frontal
region. A pair of slightly larger spines directed forward oneither side of medial one. Regions well defined. An acute449-50, pI. 61, figs. 4, 5; Karasawa, 1993, p.46, pI. 8, fig. 4.

Superfamily Cancroidea Latreille, 1803
Family Atelecyclidae Ortmann, 1893
Genus Trachycarcinus Faxon, 1893
Type species.-By monotypy Trachycarcinus corallinus
Faxon, 1893 (ICZN Opinion 73).
Geologic range.-Oligocene to Recent.

Figure 4. 1-3. Upogebia sp. 1: a and b. inner and outer views of manus of left chela. IGPS 102440, Us, X 1.5. 2: aand b. do~sal and ~ateral views of carapace. IGPS 102439, Us, x 1.2. 3: a and b. dorsal and lateral views of carapace
and abdominal somltes. IGPS 102~, Us~ x 1.0. 4. Eucalliax sp. a and b. outer and inner views of chelae (plaster cast).
IGPS 102713, Ng-4, X1.0. 5-6. Callianops/s sp. 1. (plaster cast). 5: chelipeds. IGPS 102727, Ng-18, X 1.0. 6: chelipeds.
IGPS 102721, Ng-4, X1.0. 7-8. Callianopsis sp. 2. 7: outer view of left chela. IGPS 102730, Yz-4, X 1.2. 8: outer viewof left chela. IGPS 102731, YZ-4, X1.2. 9. Munida sp. cf. M. nishioi Karasawa. dorsal view of carapace. IGPS 102755 Ng21, X1.2. 10-13. Mursia takahashii Imaizumi. 10: outer view of left chela. IGPS 102773, Ng-9, X 1.2. 11: dorsal vi~w ofcara~ace. IGPS 102770, Ng-10, x1.0. 12: dorsal view of carapace. IGPS 102771, Ng-9, X 1.0. 13: carapace withchellpeds. IGPS 102772, Ng-9, x 1.0.

1015. Miocene decapods from Chichibu Basin

la

Ib

509

Hisayoshi Kato

510

Trachycarc;nus ;nflatus sp. nov.

Figures 5-1a-4
Material.-IGPS coil. cat. no. 102781-102806. Holotype:
IGPS, coil. cat. no. 102783 (carapace). Paratypes: IGPS,
coil. cat. no. 102784 (carapace, plaster cast); 102784 (rightchela).
Occurrence.-Nagura Formation.
Etymology.-From the elevated dorsal regions.
Diagnosis.- Trachycarcinus with dense, flattened granules
on elevated dorsal regions. Dorsal regions terrace-shaped,
marked by deep furrows. Surface of manus of male larger
cheliped smooth, without granules.
Description.-Carapace pentagonal in outline; Slightly
longer than wide. Dorsal surface strongly convex. Dorsal
regions well marked by deep furrows, strongly elevated with
dense, flattened granules. Protogastric region strongly
convex. Mesogastric region triangular, separated frommetagastric region by a shallow furrow. Hepatic region
strongly granulated. Cardiac region consisting of two conical swellings arranged transversely. Intestinal region weakly elevated with sparse granules. Posterior margin broad.
Carapace transversely constricted behind intestina1 region.
Rostrum with three spines directed forward, slightly upturned.
Median rostral spine produced slightly more forward thanlaterals. Inner supraorbital spine triangular, without granules. Outer supraorbital and postorbital spines acute.
Anterolateral margin with four spines including postorbitalone. Postorbital spine directed forward. Second spine
near posterior end of hepatic region, directed obliquely
forward. Third and 4th spines on lateral margin of epi- andmesobranchial regions, directed laterally. Each spine ornamented by granules variable in size.
Manus of male larger cheliped oblong with smooth surface. Dactylus slender, distinctly longer than fixed finger.
Both fingers without remarkable granules or grooves. Six toseven conical teeth observed on the cutting edge of
dactylus.
Remarks.- The present new species closely resembles
Trachycarcinus huziokai Imaizumi, 1951 from the Miocene
Oguni Group of Yamagata Prefecture in the general shapeand ornamentation of the carapace and in the shape of themale larger cheliped. Besides the type locality, Imaizumi(1958a) has documented eight localities of T. huziokai fromthe Early to Middle Miocene of Japan including the Chichibu
Basin. Karasawa (1990) added an additional locality for thisspecies from Southwest Japan.
Examinations of the plaster cast from the outer mould of

the carapaces, however, reveal that the present material isclearly distinguishable from T. huziokai by having terraceshaped dorsal regions of the carapace with flattened granules that are marked by deep furrows, and male larger chela
without remarkable granules on the inner and outer surfacesof the manus and fingers without grooves.
Among the living species, T. crosnieri Guinot, 1986 resembles the present new species in the general arrangement of
the dorsal regions and shape of the anterolateral spines, butdiffers in the shape of the rostral spines. Trachycarcinus
alcocki (Doflein, 1904) resembles T. in flatus in the generaloutline of the carapace, but possesses spiniform large tubercles on the lateral margin and dorsal surface of the carapace.
Family Cancridae Latreille, 1803
Genus Cancer Linnaeus, 1758
Type species.-By subsequent designation of Latreille,
1810; Cancer pagurus Linnaeus, 1758.
Geologic range.-Miocene to Recent.

Cancer sakamoto; sp. nov.
Figures 5-5-9b
Cancer sanbonsugii Imaizumi, 1962, p. 235, 237, pI. 40, figs. 2, 3, 7
(paratypes nos. 1, 2, 5 by original designation).
not. Imaizumi, 1962, p. 233, 234, pI. 40, figs. 1, 4, 5 (holotype,paratype no. 3).

Material.-IGPS coli. cat. no. 102807-102833. Holotype:
IGPS, coil. cat. no. 102807 (inner cast and outer mould ofcarapace). Paratypes: IGPS, coil. cat. no. 102808 (carapace with chelipeds); 102809 (carapace with cheliped).
Occurrence .-Nagura Formation.
Etymology.-In honor of Mr.Osamu Sakamoto who hasmade large contributions to paleontology of the Chichibu
Basin.
Diagnosis.-Moderate-sized Cancer with variable sized
granules on restricted dorsal regions. Anterolateral teeth
with pointed tips; separated from each other by closed
fissures. Manus with a ridge armed with three subconicalteeth on upper margin and four longitudinal granulated ridges
on outer surface.
Description.-Carapace transversely oval in outline.
Regions covered with scattered granules of variable size;
well divided by deep, wide furrows. Proto- and mesogastricregions most convex. Hepatic region bearing a triangular
node. Epibranchial region bearing two tubercles among

Figure 5. 1-4. Trachycarcinus inflatus sp. nov. 1: paratype, a and b. outer and inner views of right chela. IGPS
102781, Ng-4, x1.0. 2: paratype, dorsal view of carapace (plaster cast). IGPS 102784, Ng-4, X 1.0. 3: holotype, dorsal
view of carapace. IGPS 102782, Ng-4, X 1.2. 4: dorsal view of carapace. IGPS 102783, Ng-4, X 1.2. 5-9. Cancer
sakamotoi sp. nov. 5: dorsal view of carapace. IGPS 102811, Ng-9, X1.0. 6: paratype, a, band c. left cheliped, dorsal
and ventral views of carapace with chelipeds. IGPS 102808, Ng-4, X 1.0. 7: holotype, carapace (plaster cast), IGPS
102807, Ng-4, x1.0. 8: paratype, outer view of left chela, IGPS 102809, Ng-4, X1.5. 9: a and b. outer and inner viewsof right chela. IGPS 102812, Ng-4, X1.0. 10. Cancer sp. a and b. outer and inner views of right chela. IGPS 102834, Ng4, X1.0. 11. Itoigawaia chichibuensis sp. nov. holotype, dorsal view of carapace, IGPS 102837, Ng-4, X 1.0.

1015.

Miocene decapods from Chichibu Basin

511

8
la

9a
Ib

6a
9b

2

lOb

512

Hisayoshi Kato

scattered granules. Mesobranchial region possessing two
granulated tubercles. Metabranchial region with two or
three swellings. Two conical nodes situated transversely on
cardiac region. Frontal margin with five spines including
small, but clearly acutely triangular inner supraorbital ones.
Medial one smallest and depressed. Anterolateral margin
bearing nine acutely pointed spines separated from eachother by short closed fissures; fringed by granules. Second
and 4th spines slightly smaller than neighboring spines.
Posterolateral margin bearing three or four blunt, upturned
spines diminishing in size posteriorly.
Chelipeds nearly equal in size and shape. Manus withfive granulated carinae extending longitudinally on upper
margin and outer surface; the uppermost, on upper marginpossessing three subconical, granulated spines; second
obscure with sparse granules; 3rd and 4th distinct, densely
granulated. Fixed finger with five conical teeth, suboval insection; lower margin straight, thickened; tip slightly
upturned. Inner and outer surfaces of fixed finger grooved
along lower margin and lined with pits along opposing
margin. Dactylus with blunt, conical teeth on cutting edge;coarsely granulated on upper margin near proximal articulation ; three longitudinal grooves with rows of pits on outersurface and near lower margin on inner surface. Carpus
possessing five granulated carinae. Merus triangular incross section.
Remarks.-Critical examinations of the type series ofCancer sanbonsugii Imaizumi, 1962 from the Middle Miocene
Matsukawa Formation ("Odaira Formation" in Imaizumi's
description) of Fukushima Prefecture, together with material
subsequently collected from the type locality and specimensfrom the Chichibu Basin, led to the conclusion that the type
series included two distinct species. Of Imaizumi's specimens, his holotype and paratype no. 3 (p. 233, 234, pI. 40,
figs. 1, 4,5) are here considered to belong to C. sanbonsugii,
and paratypes nos. 1, 2 and 5 (p. 235, 237, pI. 40, figs. 2, 3, 7)
to the new species C. sakamotoi.
C. sakamotoi closely resembles C. sanbonsugii in thegeneral shape of the carapace, but may be distinguished byhaving a densely granulated rather than smooth dorsal
surface of the carapace, and in having granulated andcarinated chelae. Among the species living in Japanesewater, C. amphioetus Rathbun, 1898 resembles C. sakamotoi
in having strongly elevated dorsal regions as already suggested by Imaizumi (1962). Moreover, C. sakamotoi resembles the Recent C. gibbosulus (De Haan, 1833) from Japan in
the shape of frontal and anterolateral spines of the carapace.

Cancer sp.
Figures 5-10a, bMaterial.-IGPS coil. cat. no. 102834.
Occurrence.-Nagura Formation.
Description.-Manus long with six longitudinal carinae onouter and upper surfaces. Uppermost one on upper margin
bears nine triangular spines. Third, 6th and 9th spines,
smaller than others. Each spine finely granulated. Second
carina gently swollen. Third extending along boundary
between upper and outer surfaces. Third to 6th carinae
weakly developed. Fixed finger covered with densely
mammillated tubercles on both surfaces, slightly inclined. A
row of pits lie within a groove on outer surface. A broad,shallow groove with a row of pits on middle part and a row
of slightly larger pits at base of cutting edge discernible on
inner surface. Cutting edge armed with seven teeth ofvariable size.
Outer and inner surfaces of carpus covered with a microscopic mesh of pores, bounded by a strong carina. Outerangle of upper surface forming a large spine projecting
distally.
Remarks.- This species resembles Cancer (Cancer) tomowoi Karasawa, 1990 from the Miocene Mizunami Group in
the general proportion and ornamentation of the outer surface of the chela, but there are some differences between
the two in the following: the cutting edge of the fixed fingerof the present species is armed with seven teeth while C. (C.)
tomowoi has five teeth; the upper margin of the manus hasnine spines, whereas C. (C.) tomowoi possesses only three.

Superfamily Portunoidea Rafinesque, 1815
Family Portunidae Rafinesque, 1815
Subfamily Polybiinae Ortmann, 1893
Genus Itoigawaia Karasawa, Sakumoto and
Takayasu, 1992
Type species.-By monotypy Portunites minoensis Karasawa, 1990.
Geologic range.- Miocene.

Itoigawaia chichibuensis sp. nov.
Figures 5-11 ; 6-7a-12

Material.-Holotype: IGPS coil. cat. no.102837 (carapace): Paratypes: IGPS coil. cat. no. 102840 (chelipeds);
102843 (male abdomen and thoracic sternites).
Occurrence. -Nagura Formation.
Etymology.-From the Chichibu Basin.

Figure 6. All figures except 7 are natural size. 1-6. Minohellenus? sp. 1-3: a and b. outer and inner views ofdactylus of right cheliped, 1: IGPS 102858, Ng-4. 2: IGPS 102859, Ng-4. 3: IGPS 102861, Ng-4. 4: a, band c. inner,outer and upper views of left fixed finger, IGPS 102860, Ng-4. 5: a and b. outer and inner views of right manus, IGPS 102862,
Ng-4. 6: a and b. dorsal and ventral views of carapace, IGPS 102863, Ng-4. 7-12. Itoigawaia chichibuensis, sp. nov. 7:
a, band c. inner, outer and upper views of left fixed finger. IGPS 102838, Ng-4, x1.2. 8: left manus, IGPS 102839, Ng4. 9: right chela, IGPS 102840, Ng-4. 10: female abdomen, IGPS 102842, Ng-4. 11: fifth pereiopod, IGPS 102841, Ng-4.
12: male abdomen and thoracic sternum, IGPS 102843, Ng-4.

1015. Miocene decapods from Chichibu Basin

5 13

Ib

3b

2b

4c

5a

7b

5b

7c

II

514

Hisayoshi Kato

Diagnosis.-Itoigawaia with broadly triangular inner supraorbital angle and acutely pointed outer supraorbital spine.
Upper surface of manus bounded by two keels.
Description. -Carapace broader than long; covered allover with dense granules which coarsen in anterior portion ofcarapace. Regions well defined. Frontal and hepatic
regions depressed in contrast to swellings of gastric andbranchial regions. Protogastric region broad, strongly convex; steeply sloped anteriorly. Meta- and mesogastricregions well marked. Urogastric region depressed. Cervical groove between gastric and branchial regions broad,deep, granules less developed. Epibranchial region strongly
convex, forming broad, arched ridge terminating near cervical furrow. Mesobranchial region strongly convex. Cardiac region gently convex. Frontal margin with four acutespines. Median pair projecting slightly beyond laterals.
Outer supraorbital spine acutely triangular, projected forward.
Suborbital spine acute with broad base, directed forward.
Anterolateral margin gently convex with five subequal
spines. First (exorbital) sharp, directed forward. Second to
4th almost equal in shape and size. Fifth directed obliquelyanteriorly. Posterior margin narrow, slightly convex.
Chelipeds subequal in size and shape. Manus relatively
short, hexagonal in cross section. Upper surface marked by
two keels with distal projections; inner projection developed
into a conical spine. Fixed finger triangular in lateral view;
cutting edge bears 10 teeth; lower margin almost straight,
but tip slightly upturned; outer and inner surfaces with tworows lined with small pits. Dactylus weakly curved downward; cutting edge armed with 13 or more small teeth.
Merus of walking legs broad; dactylus longitudinallycarinated. Dactylus of fifth leg flattened, typically ovate inoutline; propodus also flattened; carpus without carina.
Telson of male abdomen broader than long; proximal
margin indented into much broader 6th somite. First-4th
somite of female abdomen forming pleats. Third thoracic
sternite rectangular, longer than broad in both left and right
portion.
Remarks.-Itoigawaia chichibuensis is characterized byhaving a large carapace which is covered with coarse
granules. This species is distinguished from the type Itoigawaia minoensis (Karasawa, 1990) from the Lower Miocene
Mizunami Group in having a large, triangular inner supraorbital spine, an acutely projecting outer supraorbital spine andangular chelae with densely serrated fingers. In I. chichibuensis the dorsal surface of the carapace has welldefined regions which are more elevated than in I. minoensis.
Itoigawaia umemotoi Karasawa, 1993 from the Mizunami
Group resembles the present new species in having acutefrontal spines and a large, fan-like carapace; I. chichibuensis differs from I. umemotoi by having the large inner supraor-

bital spine and two keels and projections on the uppersurface of the chelipeds.
Genus Minohellenus Karasawa, 1990
Type species.-By monotypy Charybdis (Minohellenus)
quinquedentata Karasawa, 1990.
Geologic range.-Oligocene to Miocene.

Minohellenus? sp.
Figures 6-1a---6b
Material.-IGPS coil. cat. no. 102858-102869.
Occurrence.-Nagura Formation.
Description.-Carapace suboval in outline. Front narrow,separated from supraorbital spine by a distinct notch.
Upper orbital margin concave, rounded; interrupted laterally
by two fissures. A distinct transverse ridge extending frommesogastric region to hepatic region. An arched ridge
formed by epi- and mesobranchial regions extending from
5th anterolateral spine terminates at cervical furrow.
Manus relatively short; exhibiting, in part, a meshy surface. Fingers robust, stout, oval in cross section. Fixedfinger triangular in lateral view; cutting edge armed with arow of strong teeth, of which proximal two or three haveconical, flattened crushing surface. Dactylus strongly arcuate downward and slightly curved inward with five longitudinal rows of pits; cutting edge armed with seven conicalteeth, proximal most tooth largest.
Remarks.- This species is recognized by the features ofthe fronto-orbital margin, well developed transverse ridges
on the carapace and stout fingers with conical crushingteeth on the cutting edges. The present species is quite
different from the type Minohellenus quinquedentatus Karasawa, 1989 from the Miocene Mizunami Group and M.
macrocheilus Kato and Karasawa, 1994 from the Oligocene
Ashiya Group in having the large chelae with stout fingers
mentioned above.

Superfamily Xanthoidea MacLeay, 1838
Family Xanthidae MacLeay, 1838
Subfamily Euxanthinae Alcock, 1898
Genus Medaeus Dana, 1851
Type species.-By monotypy Medaeus ornatus Dana, 1852
(lCZN Opinion 712).
Geologic range.-Miocene to Recent.

Figure 7. 1. Medaeus? sp. dorsal view of carapace. IGPS 102895, Yz-6, X 1.0. 2. Typhrocarcinodes? sp. dorsal
view of carapace, left chela and walking legs. IGPS 102973, Ng-18, x 2.0. 3. Carcinoplax sp. carapace with right cheliped.
IGPS 102972, Ng-6, x1.5. 4-8. Carcinoplax antiqua (Ristori). X 1.0. 4: carapace with chelipeds. IGPS 102922, Ng-9. 5:
a and b. dorsal and ventral views of carapace and chelipeds. IGPS 102923, Ng-9. 6: carapace with cheliped. IGPS
102924, Ng-9. 7: carapace with right cheliped and walking legs. IGPS 102925, Ng-9. 8: a and b. outer view of chelae
and dorsal view of carapace. IGPS 102965, Ng-3.

1015.

Miocene decapods from Chichibu Basin

5 15

8a

Hisayoshi Kato

516

Medaeus? sp.
Figure 7-1
Materia/.-IGPS coli. cat. no. 102895-102896.
Occurrence.- Yokoze Formation.
Description.-Carapace transversely octagonal in outline.
Front broadly projected forward; anterior margin slightly
concave but not divided into two lobes. Lateral angle offrontal I~be forming forwardly directed spine. Inner orbital
spine distinct but hiatus indiscernible. Regions well definedby deep sculpture, but anterior portion of carapace almost
eroded. Proto-, meso- and metagastric, cardiac, epi-, mesoand metabranchial regions tumid, covered with granules
densely. Mesogastric region nearly regularly triangular.
Metagastric fused with mesogastric region at median longitudinal. Epibranchial region clearly defined by deep furrow.
Fused cardiac and intestinal region lozenge-shaped; widest
in preserved regions. Posterior margin long.
Orbital margin badly preserved. Anterolateral margin
bearing five spines. First (external orbital spine) and 2ndacutely triangular, nearly equal in size. Third and 4th
apparently small. Fifth largest and acutely triangular, projecting laterally.
Remarks.-The present species resembles the Recent
Medaeus serratus Sakai, 1965 from Japan in the generalshape of the carapace, but differs from M. serratus in theabsence of the V-shaped frontal notch and in having afrontal spine on the lateral frontal angle. This species isdistinguished from other Medaeus species in the absence ofthe frontal notch and in having the posterior margin unusuallywider than that of the living species. Additional specimensof this species are necessary in order to make an exact
generic assignment.
Family Goneplacidae MacLeay, 1838
Subfamily Carcinoplacinae H. Milne Edwards, 1852
Genus Carcinop/ax H. Milne Edwards, 1852
Type species.-By subsequent designation by Glaessner,
1929; Cancer (Curtonotus) longimanus De Haan, 1833.
Geologic range.-Eocene to Recent.

Carcinop/ax antiqua (Ristori, 1889)
Figures 7-4--8
Curtonotus antiqus Ristori, 1889, p. 4.
Carcinoplax antiqua Glaessner, 1933, p. 17; Imaizumi, 1961, p.

164, text-fig. 4, pI. 12, pI. 13, figs. 1-11, pis. 14-5, pI. 16, figs. 45, pI. 17, figs. 2-11; 1969, pI. N-8, fig. I; Fujiyama, 1982, p.
370, figs. 1834-5 ; Karasawa, 1990, p.23-25, pI. 7; Sa-kumoto et al., 1992, p. 451, pI. 62, fig. 3, pI. 63, fig. I.
Carcinoplax senecta Imaizumi, 1961, p.172, pI. 18, figs. 1-3.
Materia/.-IGPS coil. cat. no. 102897-102971.
Occurrences.-Nenokami Sandstone Member; Nagura
Formation; lower part of the Yokoze Formation.
Remarks.-There are remarkable size differences between
specimens from the Nenokami Sandstone Member and fromthe Nagura Formation. The carapace width of those fromthe Nenokami Sandstone Member ranges between 12-25mm while those from the Nagura Formation measure 14-44. mm' (typically 23-38 mm). Similar size differences between. materials from two horizons are also observed in Munida sp.

Carcinop/ax sp.
Figure 7-3
Material.-IGPS coil. cat. no. 102972.
Occurrence .-Nagura Formation.
Description.-Carapace rounded hexagonal in outline;
weakly convex dorsally. Hepatic region discernible.
Protogastric region broad, weakly swollen. A pair of shortridges situated transversely at boundary between frontal andprotogastric regions. Furrow between proto- and mesogastric regions discernible. Anterior part of mesogastric region
tapering into median furrow. Metagastric region narrow,indistinguishable. Cervical groove distinct. Cardiac regionslightly swollen. Frontal region separated into two lobes by
a furrow, however, frontal margin nearly straight without
distinct notch. Orbital margin broad, rounded. Inner supraorbital angle clearly separated from lateral angle of frontal
margin. Outer supraorbital margin tumid dorsally. Anterolateral margin gently convex outward with three spines including postorbital one. Postorbital spine largest, directing
forward. Second and 3rd anterolateral spines faintly visible.
Anterolateral margin slightly narrower than posterolateralone. Posterolateral margin slightly convex. Posterior margin straight.
Right cheliped slender. Cutting edge of fixed finger withapproximately ten small, blade-shaped teeth. Upper surface of carpus broadly rectangular in dorsal view.
Remarks.-The present species is quite different from the
known fossil species of Carcinoplax in having a more circular
carapace, a broad orbital margin and faintly anterolateralspines. In having a circular carapace, the extant species C.
angusta Rathbun, 1914 from the South China Sea bears someresemblances to Carcinoplax sp., but differs in having astrongly tumid carapace.

Figure 8. 1-7. Miosesarma nagurense n. sp. 1: a and b. inner and outer views of right chela. IGPS 103074, .Ng-6,
x2.5. 2: paratype, ventral view of male abdomen and thoracic sternum. IGPS 102974, Ng-13, X1.2. 3: dorsal view offemale carapace with chelipeds and walking legs. IGPS 103075, Ng-16, X 1.0. 4: paratype, dorsal view of carapace withwalking legs (plaster cast). IGPS 103081, Nk-2, X 1.0. 5: holotype, dorsal view of male carapace with chelipeds andwalking legs. IGPS 102976, Ng-9, x 1.0. 6: dorsal view of female carapace with cheliped and walking legs. IG~S 102~75,
Ng-13, X 1.0. 7: dorsal view of carapace with chelipeds and walking legs. IGPS 103080, Ng-.8, x1.2. 8-9. M~Ja mon~ sp.
nov. x1.0. 8: paratype, dorsal view of carapace. IGPS 103101, Ng-13. 9: holotype, dorsal view of carapace With cheliped
and walking legs. IGPS 103100, Ng-13.

1015.

Miocene decapods from Chichibu Basin

517

Hisayoshi Kato

518
Subfamily Rhizopinae Miers, 1886
Genus Typhlocarcinodes Alcock, 1900

Type species.-By monotypy Typhlocarcinus integrifrons
Miers, 1881.

Typhlocarcinodes? sp.
Figure 7-2
Materia/.-IGPS coil. cat. no. 102973.
Occurrence.-Nagura Formation.
Description.-Carapace oval in outline without any projection or spine along margin; moderately convex; dorsal
surface covered all over with irregularly pointed granules.
Frontal margin hardly distinguishable. Orbits not recognizable on dorsal surface. Cervical groove shallow. Cardiac
region discernible.
Left chela very small. Observable part of chela about half
as long as carapace length. Manus swollen, showing irregularly granulated upper surface. Fixed finger with strong
keel on lower margin of outer surface. Walking legs also
granulated.
Remarks.- The present species .may be assigned toTyphlocarcinodes by having a granulated carapace which is
wider than long, smooth margins of the carapace without
projections or spines, and orbits which cannot be observed
from the dorsal surface. However, the poor preservation of
the present material renders it difficult to determine its exact
generic position.

longitudinally. Metagastric region also highly convex with alarge, conical tubercle. Urogastric region with a conicaltubercle noticeably smaller than others. Cardiac region
marked by broad, plain furrows; strongly convex with alarge, conical tubercle in middle part. Intestinal regionswelling into conical elevation. Hepatic region narrowly
convex; marked by broad, plain furrows. Branchial regionswith large numbers of variable sized tubercles. Sinuous
swellings consisting of large tubercles extending parallel tobranchiocardiac groove. Metabranchial region with small
tubercles and granules; less developed than mesobranchialand intestinal swellings. Supraorbital eave with sparse
granules. Antorbital spine acutely triangular, directing laterally. Intercalated spine short (about half length of antorbital
and one third length of postorbital spines). Postorbital spine
triangular, directed anteriorly; anterior surface excavated.
These three spines closely approximated. Propodus of leftchela straight; outer surface longitudinally carinated. Fingers thin with acutely pointed tips. Walking legs long,
slender. Merus cylindrical. Carpus and manus slightly
flattened.
Remarks.-Maja morii most resembles the fossil species
Maja biaensis L6renthey in L6renthey and Beurlen, 1929 from
the Middle Miocene of Hungary, in the general arrangementof tubercles and lateral spines on the carapace. However
M. morii is readily distinguished from M. biaensis in having asingle tubercle on the posterior end of the carapace. The
present record documents the first occurrence of a fossil
Maja species in the northern Pacific region.

Superfamily Majoidea Samouelle, 1819
Family Majidae Samouelle, 1819
Subfamily Majinae Samouelle, 1819
Genus Maja Lamarck, 1801

Section Thoracotremata Guinot, 1977
Superfamily Grapsoidea MacLeay, 1838
Family Grapsidae MacLeay, 1838
Subfamily Sesarminae Dana, 1851
Genus Miosesarma Karasawa, 1989

Type species.-By subsequent designation under theplenary powers; Cancer squinado Herbst, 1788 (ICZN opinion
511)
Geologic range.-Miocene to Recent.

Type species.-By monotypy Miosesarma japonicum Karasawa, 1989.
Geologic range.-Miocene.

Maja marii sp. nov.

Miosesarma nagurense sp. nov.
Figures 8-1a-7

Figures 8-8, 9Materia/.-Holotype: IGPS coil. cat. no. 103100 (carapace,left chela, merus and carpus of walking legs). Paratype :IGPS coil. cat. no. 103101 (carapace).
Occurrence.-Nagura Formation.
Etymology.-In honor of Professor Kei Mori, who supported
the present study and made useful suggestions.
Diagnosis.-Maja with moderately long and slightly divergent rostrum. Three orbital spines approximated. Posterior
margin of carapace bearing single conical tubercle.
Description. -Carapace pyriform. Rostrum with acutespines slightly divergent. Regions well defined. Medianlongitudinal, branchial and hepatic regions strongly convex.
Protogastric region bearing two longitudinal series of conicaltubercles, extending to base of rostrum. Mesogastric region
strongly convex with two large, conical tubercles arrangedCamptandrium ? sp.

Fujiyama, 1982, p.370, pI. 185, fig. 1840.

Materia/.-IGPS coil. cat. no. 102974-103095. Holotype:
IGPS coil. cat. no.102976 (carapace with chelipeds andwalking legs). Paratypes: IGPS coil. cat. no. 102974 (carapace, thoracic sternum and abdomen); IGPS coil. cat. no.
103081 (carapace with walking legs).
Occurrences.-Nenokami Sandstone Member; Nagura
Formation; lower part of the Yokoze Formation.
Etymology.-From the Nagura Formation, which yields
abundant specimens.
Diagnosis.-Miosesarma with a triangular process onmesobranchial region in which mesobranchial sharp, oblique
ridge terminated. Hepatic region depressed.
Description.-Carapace quadrilateral in outline, about
three-fourths as long as wide. Dorsal surface moderately

1015.

Miocene decapods from Chichibu Basinconvex. Frontal region bilobed. A pair of short but strong
ridges arranged transversely at boundary between frontal
and protogastric regions. Hepatic region depressed.
Protogastric region gently convex. Bottle-shaped
mesogastric region wei] .defined; surface slightly flattened;
tapering anteriorly into median furrow. Cardiac region transversely hexagonal; well marked and convex. Epibranchial
lobe transversely tumid with a sharp ridge extending from 3rd
anterolateral spine to mesobranchial lobe. Mesobranchial
lobe strongly tumid with a sharp ridge extending from 4th
anterolateral spine into transversal ridge; terminated in atriangular process. Cardiac and branchio-cardiac furrows
distinct. Frontal margin narrow (about 0.24-0.26 of carapace width). Inner orbital margin slightly concave at baseof frontal lobe; outer orbital margin sinuous, reaching topostorbital angle. Anterolateral margin bearing four spines
including postorbital angle. First largest, thorn-shaped,
flattened, directed forward. Second small, directed obliquely anteriorly, with pOinted tip. Third large with tip pointing
upward. Fourth rudimentary, at lateral end of mesobranchial ridge. Posterolateral margin slightly convergent.
Penultimate somite of male abdomen not broad; slightly
longer than 3rd to 5th somites. Telson narrow; slightly
indented into penultimate somite.
Manus of mature male cheliped elongated, triangular incross section. Fixed finger with acutely pointed tip, slightly
curved downward and inward. Cutting edge of finger poorly
preserved. Walking legs long.
Merognath of third maxilliped nearly rectangular. Ischiognath larger than merognath; with nearly right-angled
posterointernal angle; external half depressed. Exopodite
short.
Remarks.-Miosesarma nagurense sp. nov. is readily distinguished from the type Miosesarma japonicum Karasawa,
1989 from the Miocene Mizunami Group in having thehepatic region depressed and a triangular process on themesobranchial region. The dorsal surface of the present
new species is more unevenly convex and regions are better
defined than are those of M. japonicum. The chelipeds ofmature specimens show distinct sexual dimorphism. The
chelae of mature females are tiny and slender, whereas themale ones are long and stout.
References cited

Alcock, A., 1898: Materials for a carcinological fauna of
India. No.3. The Brachyura Cyclometopa. Part I.
Family Xanthidae. Journal of the Asiatic Society ofBengal, vol. 67, part 2, no. 1, p. 67 - 233.
Alcock, A., 1900: Materials for a carcinological fauna of
India. No.6. The Brachyura Catametopa or Grapsoidea. Journal of the Asiatic Society of Bengal, vol.
69, part 2, no. 3, p. 280-456.
Arai, J., 1960: Part I. Sedimentology. In, Arai, J. and
Kanno, S. The Tertiary System of the Chichibu Basin,
Saitama Prefecture, central Japan. p. i-v, 1-122, i-v, 30
pis. The Japan Society for the Promotion of Science,
Ueno, Tokyo.
Biffar, T.A., 1970: Three new species of callianassid shrimp(Decapoda, Thalassinidea) from the western Atlantic.

519

Proceedings of the Biological Society of Washington,

vol. 83, no. 3, p. 35-49.
Bishop, GA, 1986a: Taphonomy of the North American
decapods. Journal of Crustacean Biology, vol. 6, no. 3,
p.326-355.
Bishop, GA , 1986b: Occurrence, preservation, and biogeography of the Cretaceous crabs of North America. In,
Gore, R.H. and Heck, K.L. eds., Crustacean Issues, vol.
4, Crustacean Biogeography, p. 111-142, A.A. Balkema,
Rotterdam.
Blow, W.H., 1969: Late Middle Eocene to Recent planktonic
foraminiferal biostratigraphy. In, Bronnimann, P. andRenz, H.H. eds., Proceedings of the First International
Conference on Planktonic Microfossils, Geneva, 1967,

vol. 1, p.199-421. E.J. Brill, Leiden.
Boas, J.E.V., 1880: Studier over Decapodernes Slaegtskabsforhold. Videnskabernes Selskabs Skrifter, vol. 5, no.
6, p.5-210.
Borradaile, L.A., 1903: On the classification of Thalassin idea. Annals and Magazine of Natural History,
Series 7, vol. 7, no. 53, p. 534-551.
Dana, J.D., 1851 : On the classification of the Cancroidea.
Silliman's American Journal of SCience and Arts, Series

2, vol. 12, p.121-131.
Dana, J.D., 1852: Crustacea.

In, United States Exploring
Expedition During the Years 1838, 1839, 1840, 1841,
1842 Under the Command of Charles Wilkes, U.S.N.,

vol. 13, 1620 p.
Desmarest, A.G., 1823: Crustaces Malacostraces. In, A.G.
Desmarest, Dictionnaire des Sciences Naturelles, vol.
28, p. 138-156. F.G. Levrault et Le Normant, Strasbourg
and Paris.
Doflein, F., 1904: Brachyura. In, Carl Chun, Wissenschaftliche Ergebnisse der Deutschen Tiefsee Expedition auf
dem Dampfer "Valdivia" 1898-1899, vol. 6, p. i-xiv, 1-

314, figs. 1-68, pis. 1-57. Jena.
Fabricius, J.C., 1775: Systema entomologiae, sis tens insectorum classes, ordines, genera, species, adiectis
synonymis, locis, descriptionibus, observationibus. 832

p. Libraria Kortii, Flensbergi and Lipsiae.
Faxon, W., 1893: Preliminary descriptions of new species of
Crustacea. Bulletin of the Museum of Comparative
Zoology, Harvard College, Cambrige, vol. 24, no. 7, p.
149-220.
Fujiyama, I., 1982: Cenozoic Crustacea (Decapoda). In,
Fujiyama, I. et al. eds., "Fossil Catalogue for Student",
574 p. Hokuryukan Ltd., Tokyo. (in Japanese)
Glaessner, M.F., 1929: Crustacea Decapoda. Fossilium
Catalogus, vol. 41, 464 p., W. Junk, Berlin.
Glaessner, M.F., 1933: New Tertiary crabs in the collectionof the British Museum. Annals and Magazine of Natural History, Series 10, vol. 12, p. 1-28, 6 pis.
Guinot, D., 1977: Propositions pour une nouvelle classification des Crustaces Decapodes Brachyures. Comptes
Rendus Hebdomaires des Seances de I'Academie desSciences, Paris, Serie 0, vol. 285, p.1049-1052.
Guinot, D., 1986: Une nouvelle espece du genre Trachycarcinus, T. crosnieri sp. nov., de Madagascar (Crustacea
Decapoda Brachyura). Bulletin du Museum nationald'histoire naturelle Paris, Serie 4, vol. 7, Section A, no. 4,

p.805-817.
Haan, W. de, 1833-1850: Crustacea. In, von Siebold, P.F.,
Fauna Japonica sive Descriptio Animalium, quae in520

Hisayoshi Kato

Itinere per Japoniam, Jussu et Auspiciis Superiosum,qui Summum in India Batava Imperium Tenent, Suscepto, Annis 1823-1830 Collegit, Notis, Observationibus et
Adumbrationibus lJIustravit, p. i-xvii, I-XXXI, 1-24, pis. 155. A-Q, Apud auctorem, Lugduni-Batavorum.
Hayakawa, C., 1930: On the Tertiary in the Chichibu Basin.
The Journal of the Geological Society of Japan, vol. 37,
p.185-208. (in Japanese)
Herbst, J.F.w., 1782-1804: Versuch einer Naturgeschichte
der Krabben und Krebse nebst einer systematischen
Beschreibung ihrer verschiedenen Arten. 274 p., 225 p,
66 p. G.A. Lange, Berlin and Stralsund.
Hyodo, H., 1986: Geology and paleomagnetism of the
Neogene System in the Chichibu Basin, Saitama Prefecture, central Japan. Geoscience Reports of Shizuoka University, vol. 12, p. 115-152. (in Japanese withEnglish abstract)
Hyodo, H. and Niitsuma, N., 1986: Tectonic rotation of the
Kanto Mountains, related with the opening of the Japan
Sea and collision of the Tanzawa block since Middle
Miocene. Journal of Geomagnetism and Geoelectricity, vol. 38, p. 335-348.
Ijiri, S., Fujita, Y. and Toyama, K., 1950: Tertiary System in
the Chichibu Basin. Bulletin of the National Science
Museum, no. 29, p.1-68. (in Japanese)
Imaizumi, R., 1951: Trachycarcinus huziokai n. sp. from
Yamagata Prefecture. Short Papers from the Instituteof Geology and Paleontology, Tohoku University, no. 3,
p.33-40.
Imaizumi, R., 1952: Mursia takahashii n. sp. (Brachyura) from
Goishi in the Sendai Area. Short Papers from theInstitute of Geology and Paleontology, Tohoku University, no. 4, p.88-95.
Imaizumi, R., 1958a: The distributions of Trachycarcinus
huziokai Imaizumi, 1951. The Journal of the GeologicalSociety of Japan, vol. 64, p.267. (in Japanese)
Imaizumi, R., 1958b: Fossil crab from the Yanagawa Formation. The Journal of the Geological Society of Japan,
vol. 64, p.309. (in Japanese)
Imaizumi, R., 1959: Evolution of Mursia. Chikyu Kagaku,
vol. 45, p.15-22. (in Japanese)
Imaizumi, R., 1961 : A critical review and systematic descriptions of known and new species of Carcinoplax fromJapan. Science Reports of the Tohoku University, 2ndSeries (Geology), vol. 32, no. 2, p.155-193, pis. 12-21.
Imaizumi, R., 1962: Miocene Cancer (Brachyura) of Japan.
Science Reports of the Tohoku University, 2nd Series(Geology), Special Volume, no. 5, p.233-246, pI. 40.
Imaizumi, R., 1969: Miocene Crustacea from the Noto
Peninsula, Ishikawa Prefecture. Atlas of JapaneseFossils, no. 4, N-8, Tsukijishokan, Tokyo. (in Japanese)
Kanno, S., 1960: Part 2. Paleontology. In, Arai, J. and
Kanno, S., The Tertiary System of the Chichibu Basin,
Saitama Prefecture, Central Japan, p. i-iv, 123-396, i-ix,
21 pis. The Japan Society for the Promotion of Science, Ueno, Tokyo.
Kanno, S., 1980: The Chichibu Basin, In, Igo, H., Kanno, S.,
Sindo, S. and Watanabe, K. eds., "Kanto Region" inJapanese Regional Geology, p. 92-100. Asakura
Shoten, Tokyo. (in Japanese)
Karasawa, H., 1989: Decapod crustaceans from the
Miocene Mizunami Group, central Japan. Part 1.
Superfamily Thalassinoidea, Leucosioidea and Grap-

sidoidea. Bulletin of the Mizunami Fossil Museum, no.
16, p. 1-28, 3 pis.
Karasawa, H., 1990: Decapod crustaceans from thePart 2.
Miocene Mizunami Group, central Japan.
Section Oxyrhyncha, Cancridea and Brachyrhyncha.
Bulletin of the Mizunami Fossil Museum, no. 17, p. 1-33,
8 pis.
Karasawa, H., 1992: The crab Ozius collinsi sp. nov. (Xanthoidea: Decapoda: Crustacea) from the Miocene
Katsuta Group, southwest Japan. Tertiary Research,
vol. 14, no.1, p.19-24.
Karasawa, H., 1993: Cenozoic decapod Crustacea fromsouthwest Japan. Bulletin of the Mizunami Fossil
Museum, no. 20, p. 1-92, 24 pis.
Karasawa, H. and Nishikawa, I., 1991: Tha/assina anomala(Herbst, 1804) (Thalassinoidea: Decapoda) from the
Miocene Bihoku Group, southwest Japan. Transactions and Proceedings of the Palaeontological Societyof Japan, New Series, vol. 163, p.852-860.
Karasawa, H., Sakumoto, T. and Takayasu, K., 1992: A new
portunid genus Itoigawaia (Decapoda: Crustacea) from
the Miocene of southwest Japan. Bulletin of the
Mizunami Fossil Museum, no. 19, p. 455-457, 1 pI.
Kato, H. and Karasawa, H., 1994: Minohellenus macrocheilus sp. nov. (Decapoda: Crustacea) from the
Oligocene Ashiya Group, Kyushu, Japan. Bulletin of
the Kitakyushu Museum of Natural History, no. 13, p. 5158,1 pI.
Lamarck, J.B.PAde, 1801: Systeme des animaux sansvertebres, au tableau general des classes, des ordres etdes genres de des animaux···. viii, 432 p. Paris.
Latreille, PA, 1802-1803: Histoire naturelle, generale etparticuliere, des crustaces et des insectes. vol. 3, 468
p. F. Dufart, Paris.
Latreille, PA, 1810: Considerations generales sur I'ordre
naturel des animaux composant les classes des Crustaces, des Arachnides, et des Insectes, avec un tableau
methodique de leurs genres, disposes en families.
444 p. F. Schoell, Paris.
Latreille, PA, 1831 : Cours d'Entomologie, ou de I'histoire
naturelle des Crustaces, des Arachnides, desMyriapodes et des Insectes. Exposition methodiquedes ordres, des families et des genres des trois premieres classes, p. i-xiii, 1-568, atlas 26 p., 24 pis. Roret,
Paris.
Latt, K.M., 1990: The Tertiary Chichibu Basin: its sedimentation and tectonic development. Science Reports of
the Institute of Geoscience, University of Tsukuba,
Section B, vol. 11, p. 23-68.
Leach, W.E., 1814: A tabular view of the external charactersof four classes of animals, which Linne arranged underInsecta; with the distribution of the genera composing
three of these classes into orders. Transactions of theLinnean Society of London, vol. 11, p.306-400.
Leach, W.E., 1820: Galatheadees. In, Desmarest, A.G. ed.,Dictionnaire des Sciences Naturelles, vol. 11, p.49-56,
F.G. Levrault et Le Normant, Strasbourg and Paris.
Linnaeus, C., 1758: Systema naturae per regna tria naturae,
secundum classes, ordines, genera, species, cum characteribus, differentiis synonymis, locis. Edition 10, vol. 1,
p. i-iii, 1-824. Holmiae.
L6renthey, E. and Beurlen, K., 1929: Die fossilen
Decapoden der Lander der Ungarischen Krone.

1015.

Miocene decapods from Chichibu Basin

Geologica Hungarica, Series Palaeontologica, Fasciculus 3, 420 p.
MacLeay, W.S., 1838: Illustrations of the Annulosa of South
Africa. On the Brachyurous decapod Crustacea broughtfrom the Cape by Dr. Smith. In, Smith, A. ed., Illustrations of the Zoology of South Africa, p. 53-71. London.
Manning, R.B. and Felder, D.L., 1991: Revision of the American Callianassidae (Crustacea: Decapoda: Thalassinidea). Proceedings of the Biological Society ofWashington, vol. 104, no. 4, p. 764-792.
Martini, E., 1971 : Standard Tertiary and Quaternary calcareous nannoplankton zonation. In, Farinacci, A. ed.,Proceedings Second Planktonic Conference, Rome, p.
739-785.
Miers, E.J., 1881 : On a collection of Crustacea made by H.
Maltzan at Goree Island, Senegambia. Annals andMagazine of Natural History, Series 5, vol. 8, p. 204-220,
259-281,364-377, pis. 13-16.
Miers, E.J., 1886: Report on the Brachyura collected by
H.M.S. "Challenger" during the years 1873-76. The
Voyage of H.M.S. Challenger, Zoology, vol. 17, p. i-I, 1362.29 pis.
Milne Edwards, H., 1837: Histoire naturelle des Crustaces,
comprenant I'anatomie, la physiologie et la classificationde ces animaux. 532 p. Paris.
Milne Edwards, H., 1852: Observations sur les affinites
zoologiques et la classification naturelle des Crustaces.
Annales des Science Naturelles (Zoologie), Serie 3, vol.
18, p.109-166, 2 pis.
Montagu, G., 1808: Description of several marine animals
found on the South Coast of Devonshire. Transactionsof the Linnean Society of London, vol. 9, p.81-114.
Nagao, T., 1932: Two Tertiary and one Cretaceous Crustacea from Hokkaido, Japan. Journal of the Faculty of
Science, the Hokkaido Imperial University, Series 4, vol.
2, no. 1, p. 15-22, 1 pI.
Nagao, T., 1941: On some fossil Crustacea from Japan.
Journal of the Faculty of Science, the Hokkaido Imperial
University, Series 4, vol. 6, no. 2, p. 85-100, 1 pI.
Okada, H. and Bukry, T., 1980: Supplementary modificationand introduction of code numbers to the low-latitude
coccolith biostratigraphic zonation (Bukry 1973,1975).
Marine Micropaleontology, vol. 5, no. 3, p. 321-325.
Ortmann, A., 1893a: Die Decapoden-Krebse des Strassburger Museums, Abtheilung : Brachyura 1. Zoologische
Jahrbucher, Abtheilung Systematik, Geographie und
Biologie, vol. 1, no. 7, p. 23-88, 1 fig.
Ortmann, A., 1893b: Die Decapoden-Krebse des Strassburger Museums, Abtheilung: Brachyura 2. Zoologische
Jahrbucher, Abtheilung Systematik, Geographie und
Biologie, vol. 1, no. 7, p. 411-495, 1 fig.
Rafinesque, C.S., 1815: Analyse de la Nature, ou Tableau del'Univers et des corps Organises. 224 p. Palermo.
Rathbun, M.J., 1898: The Brachyura collected by the U.S.
Fish Commission Steamer Albatross on the voyage from
Norfork, Virginia, to San Francisco, California, 18871888. Proceedings of the U.S. National Museum, vol.
21, p.567-616.
Rathbun, M.J., 1902: Descriptions of new decapod crustaceans from the west coast of. North America. Proceedings of the U.S. National Museum, vol. 24, p.885-905.

521

Rathbun, M.J., 1914: A new genus and some new species ofcrabs of the family Goneplacidae. Proceedings of the
U.S. National Museum, vol. 48, p.137-154.
Ristori, G., 1889: Un nuovo crostaceo fossile del Giappone.
Atti della Societa Toscana di Scienze Naturali, vol. 7, p.
4-6.
Sakai, K., 1982: Revision of Upogebiidae (Decapod a,
Thalassinidea) in the Indo-West Pacific Region.
Researches on Crustacea, SpeCial number, 1, p.1-106.
Sakai, T., 1965: On two new genera and five new species ofxanthoid crabs from the collection of His Majesty theEmperor of Japan made in Sagami Bay. Crustaceana,
vol. 8, part 1, p. 97-106.
Saint Laurent, M. de, 1973: Sur la systematique et laphylogenie des Thalassinidea: definition des families
des Callianassidae et des Upogebiidae et diagnose decinq genres nouveaux (Crustacea, Decapoda).
Comptes Rendus Hebdomadaires des Seances de
I'Academie des Sciences, Paris, Serie 0, vol. 277, p.
513-516.
Sakumoto, T., Karasawa, H. and Takayasu, K., 1992:
Decapod crustaceans from the Miocene Izumo Group,southwest Japan. Bulletin of the Mizunami Fossil
Museum, no. 19, p. 441-453, 3 pis.
Samouelle, G., 1819: The Entomologist's Useful Compendium, or an Introduction to the Knowledge of British
Insects, etc. 496 p. T. Boys, London.
Schafer, w., 1951: Fossilisations-Bedingungen brachyurer
Krebse. Abhandlungen Senckenbergischen Naturforschenden Gessellschaft, vol. 485, p.221-238.
Takahashi, M., 1992: Geologic setting of the Miocene
Chichibu Basin in the Neogene tectonics of central
Japan. Bulletin of the Saitama Museum of Natural
History, vol. 10, p. 29-45. (in Japanese with English
abstract)
Takahashi, M., Nagahama, H. and Tanaka, Y., 1989: Age ofthe lower part of Neogene sedimentary rocks in the
Chichibu Basin, as dated by calcareous nannofossils.
Fossils (Palaeontological SOCiety of Japan), no. 46, p.19. (in Japanese with English abstract)
Takeda, M. and Fujiyama, I., 1984: A new majid crab from
the Miocene Matsuyama Group, Saitama Prefecture,
central Japan. Bulletin of the National Science
Museum, Series C, vol. 10, no. 2, p. 49-53.
Takeda, M., Oishi, M. and Fujiyama, I., 1984: A record of
Pliocene cancrid crab, Cancer minutoserratus Nagao
from the Yushima Formation, Iwate Prefecture, with anote on subgeneric diversity of Cancer in Japan.
Bulletin of the Iwate Prefectural Museum, no. 2, p. 157183.
Thorson, G., 1957: Bottom communities (sublittoral or shallow shelf). In, Hedgepeth, J. ed., Treatise on marine
ecology, vol. 1, Ecology. Geological Society of America, Memoir, 67, p.461-534.
Ujiie, H. and lijima, H., 1959: Miocene foraminifera from the
Akahira Group, Saitama Prefecture, Japan. Bulletin of
the Chichibu Museum of Natural History, no. 9, p. 69-90.
Watanabe, K., Arai, J. and Hayashi, Y., 1950: Tertiary geology of the Chichibu Basin. Bulletin of the Chichibu
Museum of Natural History, no. 1, p.29-92. (inJapanese)Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp.522-527, 3 Figs., September 30, 1996
© by the Palaeontological Society of Japan 1996

Early Late Permian (Wordian) non-ammonoid
cephalopods from the Hamrat Duru Group,
central Oman Mountains
SHWI NIK0 1 , ALAIN PILLEVUIT2 and TAMIO NISHIDA3
lDepartment of Environmental Studies, Faculty of Integrated Arts and SCiences, Hiroshima University,
Higashihiroshima, 724 Japan
21nstitute of Geology and Paleontology, University of Lausanne, BFSH 2, 1015 Lausanne-Dorigny, Switzerland
3Department of Earth Science, Faculty of Education, Saga University, Saga, 840 Japan

Received 15 October 1995; Revised manuscript accepted 1 May 1996
Abstract The Wordian Rustaq Formation is a unit of the Hawasina Nappes in the central Oman
Mountains, and contains a diverse pelagic fauna. Four species of non-ammonoid cephalopods aredescribed herein: orthocerids Brachycyc/oceras rustaqense sp. nov. and Bitaunioceras cf. zonatum(Gemmellaro), nautilid Liroceras sp. and bactritid Bactrites ? sp. One of these, Brachycyc/oceras rustaqense, represents the youngest record of the genus, previously known unquestionably only from theCarboniferous. The fauna indicates affinity to the Timor and Sicily faunas.
Key words: Orthocerids, nautilid, bactritid, central Oman Mountains, Wordian
Introduction

During the Late Cretaceous obduction of the Semail
Ophiolite, Tethyan margin sediments were thrust onto the
Arabian continental margin in the Oman Region (e.g. Glennie
et al., 1973; Robertson and Searle, 1990). The allochthonous units of sedimentary origin are called the Hawasina
Nappes and subdivided into the following six groups:
Ramaq, AI Buda'ah, Hamrat Duru, AI Aridh, Kawr and Umar
(Bechennec et al., 1988; Pi lIevu it, 1993). This report,
preceded by a preliminary report in the account of Pillevuit(1993), deals with non-ammonoid cephalopods obtained fromreddish cephalopod limestone of the Rustaq Formation of
the Hamrat Duru Group. The Permian ammonoid fauna of
the formation indicates a close resemblance to those fromthe west Mediterranean (Sosio fauna, Gemmellaro, 18871888) and Timor (Haniel, 1915), suggesting the Hawasina
Basin corresponds to a seaway along the northern margin of
Gondwana (Blendinger et aI., 1992). This faunal exchange
between the Hawasina Basin and Timor is also supported by
the investigation of the trilobite fauna by Pillevuit (1993).
The Rustaq Formation, defined by Pillevuit (1993), crops
out in the viCinity of Rustaq village in the central Oman
Mountains (Figure 1). This stratum represents the lowest
part of the Hamrat Duru Group, and consists of pillow lavas
and carbonate rocks indicating a pelagic environment. The
cephalopod limestone containing a thin barren dolomite is
2.6 m thick (Figure 2). Besides cephalopods, the Rustaq

fauna includes conodonts, ostracodes, crinoids, trilobites andserpulids. Blendinger et al. (1992) assigned a Wordian (early
Guadalupian, early Late Permian) age to the fauna, based onammonoids, including Sicanites schopeni (Gemmellaro),
Agathiceras suessi Gemmellaro and Sociocrimites insignis(Gemmellaro), and conodonts.
The specimens studied are deposited in the
paleontological collections of the Geological Museum of
Lausanne (MGL), Switzerland.
Systematic paleontology

Class Cephalopoda Cuvier, 1797
Subclass Nautiloidea Agassiz, 1847
Order Orthocerida Kuhn, 1940
Superfamily Orthocerataceae M'Coy, 1844
Family Brachycycloceratidae Furnish, Glenisterand Hansman, 1962
Genus Brachycyc/oceras Miller, Dunbar and Condra, 1933
Type species.-Brachycycloceras normale Miller, Dunbar
and Condra, 1933.

Brachycycloceras rustaqense sp. nov.
Figures 3-1-5
Cycloceratid (? Brachycycloceras) Pillevuit, 1993, p.114.

1017.

Permian cephalopods from OmanAs Suwayq

523

40 KM

Semail Ophiolite
Umar Gp.
Kawr Gp.
AI Addh Gp.

tHamrat Duru Gp.

1
('CJ

c::

III

('CJ

~

('CJ

:I:

III
Q)

Q.
Q.
('CJ

z

Autochthonous
Arabian Platform

Figure 1. Map showing fossil locality (arrow), and geology of the central Oman Mountains (modified from
Bechennec et al., 1990).

Diagnosis.-Species of strongly annulated Brachycycloceras with depressed cross section; annulations form adapicallateral sinus; siphuncular position between center andventer.
Description.-Single deciduous phragmocone, 40.8 mm inlength, of strongly annulated exogastric shell with depressedcross section, shell diameter of slightly deformed adoral end
approximately 28 mm in lateral diameter (breadth) and 21 mm
in dorsoventral diameter (height); annulations form deep
adapical sinus on lateral side, 2-3 annuli bear in length equal
to corresponding dorsoventral diameter; sutures with shallow but broad ventral lobes ; septa thin with weak cUNature ;camerae short, width (max.)/Iength ratio of camerae approximately 6-8 in dorsoventral section of adoral shell; siphuncle
narrow, between center and venter in position with suborthochoanitic short septal necks, length of septal necks ranges
from 0.5 to 0.9 mm; connecting rings not preseNed; nocameral and/or siphuncular deposits detected.
Discussion.-Although examined specimen is a fragmentary deciduous phragmocone abraded on the apical dorsalside, the distinctive shell shape and siphuncular structure
and position confirm generic identification. The known
stratigraphic distribution of Brachycycloceras was previously
restricted to sediments ranging from the Namurian (Phillips,
1985) to the Upper Pennsylvanian (Furnish et al., 1962). Onlya questionable record of a Lower Permian species of thegenus has been reported from western Australia (Teichert,
1951). This Wordian specimen thus represents the youngest

record of this genus, so this discovery from the Oman
Mountains is noteworthy.
Brachycycloceras rustaqense sp. nov. differs from all otherdescribed Brachycycloceras species in having a depressedshell cross section and the lateral sinus of the annulations.
Etymology.- The specific name is derived from the Rustaq
Formation, where the species occurs.
Material.- The holotype, MGL 72026.
Superfamily Pseudorthocerataceae Flower and Caster, 1935
Family Pseudorthoceratidae Flower and Caster, 1935
Subfamily Spyroceratinae Shimizu and Obata, 1935
Genus Bitaunioceras Shimizu and Obata, 1936

Type species.-Orthoceras bitauniense Haniel, 1915.

Bitaunioceras cf. zonatum (Gemmellaro, 1890)
Figures 3-6-11
ct. Orthoceras zona tum Gemmeliaro, 1890, p.45, pI. 11, figs. 9-11,
pI. 12, figs. 19, 20.
Bitaunioceras sp. Pillevuit, 1993, p.114.

Description.-Orthocones with gradual shell expansion,angle of expansion approximately 3-4 degrees; cross section circular; largest specimen (MGL 72027) of phragmocone attains 20.0 mm in diameter; surface ornamentation of relatively coarse transverse lirae forming salients;

Shuji Niko et a/.

524

..

"

6m

: :.::::":-

Oolitic limestone

Limestone
5 I

/

/

/

//
Dolom ite

Cephalopod limestone

DolomiteC e p h a I 0 po d lim est 0 n e

from 0.48 to 0.46, septal necks suborthochoanitic to orthochoanitic, short, 1.1 mm long in well- preserved neck ; connecting rings not preserved; internal molds of phragmocone
and body chamber bear transverse, shallow constrictions
caused by periodic thickenings of shell wall, and transverse,
straight to partly zigzag wrinkled layer ; no cameral and/ or
siphuncular deposits detected.
Oiscussion .-The specimens of Bitaunioceras cf. zona tum
from the central Oman Mountains closely resemble B.
zona tum (Gemmellaro) from the Middle Permian of Sicily in its
general shell shape, nature of surface ornamentation andwell- developed wrinkled layer. The unknown adoral siphuncular structure of the type specimens leads to thetentative specific assignment of the specimens.
Prior to the present description, Bitaunioceras had beenrecorded from Sicily, southern Urals, Timor, Japan, northern
Mexico, and Texas (Niko and Nishida, 1987). The genus
was widespread in the Tethyan region and the southern
margin of the Boreal region during Sakmarian to
Guadalupian times.
Materia/.-Two specimens, MGL 72027, an incomplete
phragmocone, 65.7 mm long, and MGL 72028, a fragment ofimmature body chamber, 30.8 mm long.
Order Nautilida Agassiz, 1847
Superfamily Clydonautilaceae Hyatt in Zittel, 1900
Family Liroceratidae Miller and Youngquist, 1949
Genus Liroceras Teichert, 1940
Type species.- Coloceras liratum Girty, 1911.

Pillow lavas with

Liroceras sp.

intra-pillow limestone

Figures 3- 12, 13-SOm

Figure 2. Stratigraphic section of the Rustaq Formation,in the Rustaq area.

length of fragmentary body chamber of immature specimen(MGL 72028) 30.8 mm and adoral shell diameter 15.9 mm ;sutures not observed, but obvious obl iquity not recognized indorsoventral section; camerae long, width (max.)/ Iength
ratio of camerae ranges from 1.1 to 1.3, septa exhibit considerably strong curvature ; siphuncular position subcentral,
minimum distance of central axis of siphuncle from shellsurface per shell diameter in dorsoventral section ranges

Oescription .- Single subglobose nautilicone with 21.5 mm
in shell diameter, whorl breadth/ height ratio 1.86 ; coilingextremely involute with umbilicus comprising less than 10
percent of diameter; whorl section reniform, roundedventrally and laterally ; shell surface smooth, lacking inconspicuous ornament without growth lines; suture simple,
nearly straight.
Oiscussion.- The specimen probably represents an immature portion of the shell. The lack of those diagnostic
features which appear in the adult shell precludes specificdetermination.
Materia/.- A specimen, MGL 72029.

Figure 3. 1- 5. Brachycycloceras rustaqense sp. nov., holotype, MGL 72026, 1 : ventral view, 2: lateral view, venter onright, 3 : septal view of adoral end, venter down, 4: dorsoventral polished section, venter on left, 5 : details of siphuncle. 611. Bitaunioceras cf. zona tum (Gemmellaro), 6- 9, MGL 72027, 6: ventral view, 7 : view of apical end, venter down, 8:
dorsoventral polished section, venter on left, arrow indicates shell constriction, 9 : details of septal neck, 10, 11, MGL 72028,
10 : side view, arrow indicates shell constriction, 11: intemal mold of body chamber showing wrinkled layer. 12, 13. Lirocerassp., MGL 72029, 12 : lateral view, 13 : apertural view. 14,15. Bactrites ? sp., MGL 72030, 14 : dorsal view showing dorsal
carina, 15: lateral view, venter on right. 4, 8 = x 2, 5, 9, 11 = x 6, all other figures = x 1.5.

1017. Permian cephalopods from Oman

525

14

Shuji Niko et a/.

526
Subclass Bactritoidea Shimanskiy, 1951
Order Bactritida Shimanskiy, 1951
Family Bactritidae Hyatt, 1884
Genus Bactrites Sandberger, 1843

Type species.-Bactrites subconicus Sandberger, 1843.

Bactrites? sp.
Figures 3-14, 15
Description.-Single incomplete body chamber of orthoconic shell, 39.8 mm in length, with circular cross-section,
weak dorsal carina; angle of shell expansion approximately
9 degrees; surface ornamentation with weak transverse
lirae.
Discussion.-The combination of carina and transverse
ornamentation of the shell surface, which is characteristic ofsome bactritids; such as the body chamber of Bactrites
peytonensis Mapes (1979, pI. 8, figs. 4-14, pI. 9, figs. 2, 3, 6-8,
12,13,15,17-19, pI. 14, figs. 7, 8, 10) and Ctenobactrites mirus
Shimanskiy (1954, pI. 9, figs. 1, 2), indicates that the specimen
can be assigned to the Family Bactritidae. In addition, thelacking of the coarse costae and/or lirae suggests the Oman
species belongs to Bactrites rather than Ctenobactrites.
Materia/.-A specimen, MGL 72030.

Acknowledgments
This study was supported by Swiss National Science
Foundation, Foundation Georgine Claraz and Lausanne
University. We thank Dr. Hilal Bin Mohd AI Azry for assistance in the field.

References cited
Agassiz, l., 1846-1847: Nomenclatoris zoologici index
universal is. Jent and Gassmann, Soloduri, 393 p. (notseen)
Bechennec, F., Le Metour, J., Rabu, D., Villey, M. andBeurrier, M., 1988: The Hawasina Basin: a fragment ofa starved passive continental margin, thrust over the
Arabian Platform during obduction of the Semail Nappe.
Tectonophysics, vol. 151, p.323-343.
Bechennec, F., Le Metour, J., Rabu, D., Bourdillon-deGrissac, CH., Wever, P. de, Beurrier, M. and Villey, M.,
1990: The Hawasina Nappes: stratigraphy, palaeogeography and structural evolution of a fragment of thesouth-Tethyan passive continental margin. In, Robertson, AH.F., Searle, M.P. and Ries, A.C. eds., The
Geology and Tectonics of the Oman Region, p.213223. Geological Society Special Publication, No. 49.
Blendinger, W., Furnish, W.M. and Glenister, B.F., 1992:
Permian cephalopod limestones, Oman Mountains:evidence for a Permian seaway along the northern
margin of Gondwana. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 93, p.13-20.
Cuvier, G., 1797: Tableau elementaire de I'histoire naturelle
des animaux. Privately published, Paris, 710 p. (notseen)
Flower, R.H. and Caster, K.E., 1935: The stratigraphy andpaleontology of northwestern Pennsylvania. Part II :Paleontology. Section A: The cephalopod fauna of
the Conewango Series of the Upper Devonian in New
York and Pennsylvania. Bulletins of American
Paleontology, vol. 22, p.199-271.
Furnish, W.M., Glenister, B.F. and Hansman, R.H., 1962:
Brachycycloceratidae, novum, deciduous Pennsylvanian nautiloids. Journal of Paleontology, vol. 36,
p. 134H356, pis. 179-180.
Gemmellaro, G.G., 1887-1888: La fauna dei calcari con
Fusulina della valle del Fiume Sosio nella provincia diPalermo. Giornale di Scienze Naturali ed Economiche,
Palermo, vol. 19, p. H06, piS. HO.
Gemmellaro, G.G., 1890: La fauna dei calcari con Fusulina
della valle del Fiume Sosio nella provincia di Palermo.
Giornale di Scienze Naturali ed Economiche, Palermo,
vol. 20, p. 37 -138, pis. 1H9.
Girty, G.H., 1911: On some new genera and species ofPennsylvanian fossils from the Wewoka Formation of
Oklahoma. Annals New York Academy of Science,
vol. 21, p.119-156.
Glennie, K.w., Boeuf, M.G.A., Hughes Clarke, M.w., MoodyStuart, M., Pilaar, W.F.H. and Reinhardt, B.M., 1973:
Late Cretaceous nappes in Oman Mountains and theirgeologie evolution. The American Association ofPetroleum Geologists Bulletin, vol. 57, p.5-27.
Haniel, CA, 1915: Die Cephalopod en der Dyas von Timor.
Palaontologie von Timor, Lieferung 3, Abh. 6, p.1-153,
pis. 46-56.
Hyatt, A., 1883-1884: Genera of fossil cephalopods. Proceedings of the Boston SOCiety of Natural History, vol.
22, p. 253-338.
Hyatt, A, 1900: Class 5. Cephalopoda. In, Zittel, KA von,Text-book of paleontology, vol. 1, p. 583-689. (reprinted
by Macmillan and Co. Ltd., London, 1927).
Kuhn, 0., 1940: Palaozoologie in Tabellen. Fischer, Jena,
50p.
Mapes, R.H., 1979: Carboniferous and Permian Bactritoidea(Cephalopoda) in North America. The University of
Kansas Paleontological Contributions, Article 64, p.175, pis. 1-41.
M'Coy, F., 1844: A synopsis of the characters of the Carboniferous limestone fossils of Ireland. Privately published,
274 p. (reprinted by Williams and Norgate, London, 1862)
Miller, AK., Dunbar, C.O. and Condra, G.E., 1933: The
nautiloid cephalopods of the Pennsylvanian system in
the Mid-Continent region. Nebraska Geological Survey, Bulletin 9, Second Series, p.1-240, pis. 1-24.
Miller, AK. and Youngquist, W., 1949: American Permian
nautiloids. The Geological Society of America, Memoir
41, p.1-218, pis. 1-59.
Niko, S. and Nishida, T., 1987: Early Permian cephalopods
from the Mizuyagadani Formation, Fukuji district, central
Japan. Transactions and Proceedings of Palaeof]tological SOCiety of Japan, New Series, no. 146, p. 3541.
Phillips, D., 1985: The nautiloid Brachycycloceras in theUpper Carboniferous of Britain. Palaeontology, vol. 28,
p.235-242.
Pillevuit, A., 1993: Les blocs exotiques du Sultanat d'Oman.
Memoires de Geologie (Lausanne), no. 17, p.1-249.
Robertson, AH.F. and Searle, M.P., 1990: The northern
Oman Tethyan continental margin: stratigraphy, struc-1017.

Permian cephalopods from Oman

ture, concepts and controversies. In, Robertson,
A.H.F., Searle, M.P. and Ries, A.C. eds., The Geology
and tectonics of the Oman Region, p.3-25. Geological Society Special Publication, No. 49.
Sandberger, G., 1843: Schilderung der palii.ontologischen
Verhii.ltnisse der alteren Formationen Nassaus. Versammlung Deutscher Naturforscher und Aerzte Mainz,
Berict 20, p.154-160.
Shimanskiy, V.N., 1951: K voprosu ob evoliutsii verkynepaleozoishikh pryamkh golovonogikh (On the evolution of
the Upper Paleozoic straight nautiloids). Doklady
Akademii Nauk SSSR, vol. 79, p.867-870, p1.1. (inRussian)
Shimanskiy, V.N., 1954: Pryamye nautiloidei i bactritoidei
sakmarskogo i artinskogo yarusov Yuzhnogo Urala(Straight nautiloids and bactritoids from the Sakmarianand Artinskian stages of the southern Urals). Akade-527

mia Nauk SSSR, Trudy Paleontologicheskogo Instituta,
vol. 44, p. H56, pis. H2. (in Russian)
Shimizu, S. and Obata, T., 1935: New genera of Gotlandianand Ordovician Nautiloids. The Journal of the Shanghai Science Institute, Section 2, Geology, Palaeontology,
Mineralogy, and Petrology, vol. 2, p. HO.
Shimizu, S. and Obata, T., 1936: Remarks on Hayasaka's
Protocycloceras dr. cyclophorum and the Permian andCarboniferous orthoconic nautiloids of Asia. Journal of
the Geological Society of Japan, vol. 43, p.11-29. (inJapanese with English abstract)
Teichert, C., 1940: Contributions to nautiloid nomenclature.
Journal of Paleontology, vol. 14, p.590-597.
Teichert, C., 1951 : The marine Permian faunas of western
Australia (an interim review). Palaontologische Zeitschrift, vol. 24, p.76-90.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp. 528-539, 5 Figs., September 30, 1996
© by the Palaeontological Society of Japan 1996

Middle Triassic (Anisian) foraminifers from the Kaizawa
Formation, southern Kanto Mountains, JapanFUMIO KOBAYASHI
Institute of Natural and Environmental Sciences, Himeji Institute of Technology,
Sanda, Hyogo, 669-13 Japan

Received 21 December 1995; Revised manuscript accepted 20 May 1996
Abstract This paper concerns the systematic paleontology and faunal comparison of newly foundAnisian foraminifers in the Kaizawa Formation distributed in the Iwai-Kanyo area, southern Kanto
Mountains. The Nishitama Group including the Kaizawa Formation in the northern part of Itsukaichi is acoherent stratigraphic unit ranging in age from the latest Permian to possibly Early Jurassic. The
formation shows many diagnostic lithologic characters indicating shallow sheH deposits, and is quite
different from those of the surrounding Jurassic formations containing numerous exotic blocks of oceanic
origin.
The foraminiferal fauna consists of 25 species assignable to 16 genera having a close Tethyan faunalaffinity. Among them, Glomospira densa (Pantie) and Meandrospira dinarica Kochansky-Devide andPantie are especially important stratigraphically as well as biogeographically, because they are zonal
indicators restricted to the Anisian of the Muschelkalk and contemporaneous limestones in Europe to West
Asia. Most of the other species are common to those reported from the Middle Triassic of the Tethyan
Realm.
Key words: Anisian foraminifers, Tethyan faunal affinity, Kaizawa Formation, Iwai-Kanyo area, Kanto
Mountains
Introduction
Triassic strata with ammonoid, various pelecypod andgastropod fossils are narrowly distributed in the Iwai area,
one of the classical and important fields for the study ofJapanese Triassic stratigraphy and paleontology (e.g. Ichikawa and Kudo, 1951). In the southern part of the Kanto
Mountains, isolated distribution of Upper Triassic strata withpelecypods is also known in the west of Ome (Takagi, 1944 ;Ozawa and Hayami, 1969). These strata show many lithologic characters diagnostic of shallow shelf deposits, and are
in striking contrast to the surrounding formations composedof Jurassic sandstone and shale including numerous exotic
blocks. No invertebrate megafossils have been found inthese Jurassic terrigenous clastic rocks.
Recently, I have found Middle Triassic foraminifers from
oolitic limestone and conglomeratic limestone in the IwaiKanyo area, the northern part of Itsukaichi. The limestone
had been thought to be referable to the uppermost Permian
Oguno Formation by Ozawa and Kobayashi (1986). The
uppermost Permian to Upper Triassic stratigraphy in this area
is re-examined in detail, and the Anisian Kaizawa Formationis newly proposed for the limestone and associated conglomeratic limestone, sandstone, and black shale (Kobayashi
and Ozawa, in press).

Although several hundreds of papers on the JapaneseUpper Paleozoic foraminifers, mostly fusulinaceans, havebeen published and over a century has passed since
Naumann (1881,1885) first reported Triassic fossils fromJapan, Triassic foraminifer research is exceedingly scarce.
Only two papers on the Triassic foraminifers have been
published. One is a brief note by Goto (1986) on theoccurrence of Meandrospira from the Kozuki-Tatsuno Belt,
Southwest Japan. The other is concerned with the composition and characteristics of the Late Triassic faunacontained in the exotic limestone blocks of the Southern
Chichibu Belt by Kristan-Tollmann (1991).
The distinguished foraminifers from the Kaizawa Formationconsist of 25 species assignable to 16 genera and show an
intimate Tethyan faunal affinity. Some of them are thought
to be stratigraphically important, and have been described orillustrated from the Middle Triassic limestones of the various
regions of the Tethyan Realm.
This paper focuses on the systematic paleontology of the
Middle Triassic (Anisian) foraminifers of the Kaizawa Formation. Faunal composition and its comparison with otherregions of the Tethyan Realm are discussed.
All the specimens illustrated and listed in this paper are
stored in the collection of the Division of Earth Sciences,
Museum of Nature and Human Activities, Hyogo.

1018.

Anisian foraminifers from Kaizawa, Japan

Geologic setting
The Nishitama Group was originally introduced by Ozawa
and Kobayashi (1986) for Middle Carboniferous to Lower
Jurassic shelf deposits in the southern Kanto Mountains.
The group in the Iwai-Kanyo area is composed of six formations in ascending order: the Oguno (Dorashamian), Iwai
(Scythian), Kaizawa (Anisian), Arai (Carnian), Kayakubo (Norian), and Kanyo (Norian possibly ranging up to Lower Jurassic) (Kobayashi and Ozawa, in press). The surrounding
formations are composed of upper Lower to Middle Jurassic
terrigeneous clastic rocks and oceanic exotic blocks ofbasaltic rocks, limestone and chert ranging in age from late
Early Carboniferous to Late Triassic. Geologic structure,litho- and bio-facies of limestone and sandstone are quite
different between the two. Moreover, diverse tectonostrati-

--=-~

529

graphic subdivision of these Jurassic accretionary complexes has been offered by various authors (Takashima andKoike, 1984; Ozawa and Kobayashi, 1986; Sakai, 1987)
Remarkable lithologic characters of the Nishitama Groupin the Iwai-Kanyo area are intercalations of impure limestone
containing detrital quartz grains, molluscan- and plant-bearing sandstone and shale, intraformational conglomerate withacidic to intermediate igneous rock pebbles and lack ofbasaltic rocks and chert. These features are strongly indicative of a deposit in shallow shelf environments. Althoughthese six formations are now fault bounded on each other, it
is considered that each younger formation had originallyrested unconformably upon the older one. The geologic
map of the Iwai-Kanyo area is shown in Figure 1.
The Kaizawa Formation, typically exposed in the south of
Kaizawa, is narrowly distributed from Iwai to Arai trending NW- ~ --- -illIill] Kanyo Formation~-:-.:.- -...: ~ conglomerate of the-_-=_

Kanyo Formation- _ -~---

Figure 1.

Nishitama Groupexcluding the Kanyo Formation

Geologic map of the Iwai-Kanyo area.

Fumio Kobayashi

530

to SE (Figure 2). It is isolatedly distributed near Kanyo(Figure 3). The Kaizawa Formation attains more than 20 min thickness, and is composed of limestone, conglomeratic
limestone, sandstone, and black shale, but their frequencies
are variable in places. Sandstone and shale less dominantly crop out due to differential erosion. Limestone cobbles to.......

......

pebbles of the conglomeratic limestone are exclusively ofDorashamian and Anisian age. All the limestone and mostof the cobbles to pebbles of Anisian age are dark gray andare classified into ooid grainstone cemented with sparrycalcite. They contain large quantities of well-sorted quartz
grains both in the matrix and nucleus of ooids. Anisian'.

: .... ; ....

":Kaizawa Formation:Iwai Formation

Tk :Takamizuyama GroupM u :Musashi Group
T :Tertiary formations zl!
Figure 2. Geologic and topographic map of the Iwai area.
localities in this area.

100

200 m

1,10-17,20-23, and 27 are foraminifer fossil

1018.

Anisian foraminifers from Kaizawa, Japan531. .' ..... "'Ka", .. :.....,'. '. rT,kjTakamizuyama G.
.'

,,"

.
.....

IKa/ Kanyo Formation:::..I~Kaizawa F.

:.::.>[~Oguno F.
".... ':: : 440..

'.; 420.

::::.:/~! " .

:. 400 c........,:..

....

:

...
...:' .:'..... '380

.

"

:'

"

:....

:'

......

:

"

'0,

I

.......

..

.... :

'

",

..

"

.•.••• I,:,.'

· ~·:·~· . ·::·k~·····::····(.::.................. "\..
'"", . . . . . . . . . . . ' : : . '.:•••••••••••••

0"·

0'

........

Ka'0,::-::::',09.......
:

"

:'

I"

.' ..

.......

..

,Ka\ /'.

'.

'. .......

'.
,

.

0
I

,,:

1 00

I

300

200
I

I

Figure 3. Geologic and topographic map of the Kanyo area.

pebbles to cobbles of algal grainstone and algal packstone
are also observable in places. Those of Dorashamian age
are gray to light gray and mostly of algal grainstone. Detrital
quartz grains are characteristically contained in almost all of
the limestone and conglomeratic limestone.
Limestones, especially algal limestones, of this formation
are highly fossiliferous. They yield algae, foraminifers,
bryozoans, sponges, crinoids, pelecypods, gastropods,
ostracods, conodonts, and others. Foraminifers are com-400
I

'5~~\~ \.. ,

~

.'

I

29-31 are foraminifer fossil localities in this area.

mon to rare in algal limestones. In almost all foraminifers
scattered in 06id grainstone the outer whorls of the tests areworn.
Composition and comparison of foraminifer fauna
Foraminifers occur at several levels of the limestone andconglomeratic limestone of the Kaizawa Formation. Localities yielded them in the Iwai and Kanyo areas are shown inFumio Kobayashi

532

ered to be stratigraphically important and restricted to theAnisian of the Muschelkalk and contemporaneous limestones widely distributed in Europe to West Asia (e.g.,Premoli Silva, 1971 ; Zaninetti et al., 1972; Gaidzicki et al.,
1975; Zaninetti, 1976; Trifonova, 1978a). In Southeast to
East Asia, G/omospira densa and species allied to Meandrospira dinarica are reported from the Anisian limestones ofPeninsular Malaysia (Gaidzicki and Smit, 1977), Guizhou (He,1984), Hubei (Lin and Zheng, 1978) and others. Although thetaxonomic treatment of the genus Arenovidalina has been

Figures 2 and 3, respectively. Distinguished 25 taxa from 17
localities are shown in Table 1. The present fauna exhibitsa striking Tethyan affinity. Although the faunal compositionand number of taxa occurring are variable, significant differences in composition are not recognizable.
Among the foraminifer species, G/omospira densa (Pantie)
is the most dominant species. Meandrospira dinarica Kochansky-Devide and Pantie is also common in the present
fauna. The occurrence of these two species in the Kaizawa Formation is worthy of note, because they are consid-

Table 1.
2 and 3.

Anisian foraminifers from the Kaizawa Formation.

Locality numbers correspond to those in Figures

1 10 11 12 13 14 15 16 17 20 21 22 23 27 29 30 31
Ammodiscus sp.
G/omospira densa
G/omospira sp.
G/omospirella irregu/aris
Rectog/omospirella sp.
Ma/ayspirina ct. fontainei
Duotaxis sp.
Gaudryina ct. triadica"Endothyra" cf. kuepperi
Endothyridae gen. et sp. indet.
Triadodiscus sp.
Triadodiscus? sp.
Arenovidalina amy/ovo/uta
Arenovidalina sp.
Au/otortus ? sp.
Involutinidae gen. et sp. indet.
Meandrospira dinarica"Meandrospira" deformata
Austroc%mia ct. marschalli
Austroc%mia sp.
Cryptoseptida ? sp.
Nodosaria expolita
Nodosaria spp.
Dip/otremina astrofimbriata
Dip/otremina sp.

X

X
X
X

X
X
X

?

X

?

X

X

X

X

X
X

X
X

X
X

X

X

X
X

?

X
X
X

?
X
X
X

X
X
X

?

X
X

X

X
X
X
X
X

X

?
X

?

X

?

X
X

X

X
X

X
X

X

X

X
X

X
X

?
?

X

X
X

X
X

X
X

X
X
X

X

X
X
X
X
X

X
X
X
X

X

X
X
X

~i.gure 4. 1,2. Ammodiscus sp., 1: Lac. 10, 02-02926a, 2: Lac. 27, 02-02947a, x120. 3-14. G/omospira densa(Pantlc), 3: Lac. 10, 02-02923a, 4: Lac. 10, 02-02926b, 5: Lac. 12, 02-02867, 6: Lac. 12, 02-02869a, 7: Lac. 10, 0202921 a, 8: Lac. 27, 02-02949a, 9: Lac. 10, 02-02917a, 10: Lac. 15, 02-13247, 11: Lac. 10, 02-02925a, 12: Lac. 27, 0202949b, 13: Lac. 31,02-02882,14: Lac. 30, 02-02879,3,4= x70; 5-14= x 80. 15,16. G/omospira sp., 15: Lac. 29, 0202874,16: Lac. 30, 02-02878, x80. 17,18. G/omospirella irregularis (Moeller), 17: Lac. 12, 02-02869b, 18: Lac. 27, 0202946a, x 80. 19. Rectoglomospirella sp., Lac. 1, 02-02952a, x 80. 20-22. Malayspirina cf. fontainei Vachard, 20: Lac.
10, 02-02923b, 21: Lac. 10, D2-02926c, 22: Lac. 12, 02-02866a, x80. 23,24. Gaudryina cf. triadica Kristan-Tollmann,
23: Lac. 23, 02-13162, 24: Lac. 10, 02-02918, x 80. 25,26. Duotaxis sp., 25: Lac. 12, 02-02871a, 26: Lac. 12, 0202868a, x80. 27-31. "Endothyra" cf. kuepperi Oberhauser, 27: Lac. 10, 02-02921b, 28: Lac. 10, 02-02917b, 29: Lac. 10,
02-02926d, 30: Lac. 10, 02-02920a, 31: Lac. 12, 02-02871b, x80. 32. Endothyridae gen. et sp. indet., Lac. 12, 0202866b, x80. 33,35. Triadodiscus? sp., 33: Lac. 21, 02-13178, 35: Lac. 1, 02-02950, X100. 34. Triadodiscus sp.,Lac. 1, 02-02952b, x100. 36,37. ArenovidaJina sp., 36: Lac. 10, 02-02927, X120, 37: Lac. 31, 02-02882c, x80. 38.
Aulotortus? sp., Lac. 1, 02-02951 a, x80. 39. Involutinidae gen. et sp. indet., Lac. 1, 02-02951b, X120.

1018. Anisian foraminifers from Kaizawa, Japan

533

534

Fumio Kobayashi

widely different among authors (Loeblich and Tappan, 1964 ;Zaninetti, 1976; Trifonova, 1978a; Pillar, 1983), this genus isalso an excellent stratigraphic indicator of the Anisian.
ArenovidaJina amylovoluta He, originally described fromsouthern Sichuan, was distinguished from A. chialingchiangensis He, the type species of the genus, by larger numbersof whorls and larger tests (Ho, 1959). This species is characteristic of the present fauna, and mostly associated with
G/omospira densa and Meandrospira dinarica.
In addition to these three species, this formation yields
some diagnostic species showing longer geologic ranges,
and also described and illustrated in various regions of the
Tethyan Realm. Endothyra kuepperi was originally described from the Carnian of the Easten Alps (Oberhauser,
1960), but it is also reported from the Anisian of the western
Carpathians (Salaj et aJ., 1967) and southern Poland (Gaidzicki and Zawidzka, 1973). Diplotremina astrofimbriata wasestablished in the Ladinian of the Eastern Alps (KristanTollman, 1964). Later, it was ascertained that the species isalso obtainable from the Pelsonian, biostratigraphicallyequivalent to the G/omospira densa Zone in the lower part of
the Muschelkalk, of southern Poland (Gaidzicki et al., 1975)
and also from the Anisian of Guizhou (He, 1984).
The above foraminifers of the Kaizawa Formation aresafely assignable to an Anisian age. This age assignment
is not in conflict with the occurrence of Neogondolellabulgarica (Budurov and Stefanov) in the lenticular conglomeratic limestone in association with Meandrospira dinarica andothers. This conglomeratic limestone was formerly regarded as part of the Arai Formation by Ozawa and Kobayashi(1986).
The present foraminifer fauna also contains forms morphologically similar to well known species in Europe that are
not always indicative of the Anisian. The chronostratigraphic distribution of Gaudryina triadica Kristan-Tollman andAustrocolomia marschalli Oberhauser has been considered tobe limited to the Upper Triassic (Carnian to Rhaetian).
"Meandrospira" deformata Salaj is probably identical withthe original materials from the Upper Anisian of the western
Carpathians (Salaj et al., 1967) and those from the Lower
Anisian of the Muschelkalk of southern Poland (Gaidzicki etaJ., 1975). In East and Southeast Asia, G/omospirellairregularis (Moeller) is known from the Anisian of southern
Sichuan (Ho, 1959) and eastern Burma (Bronnimann et al.,1975). Materials from these two localities are similar toalmost all of those referable to the genus G/omospirella from. the Kaizawa Formation. The genus Malayspirina proposedfrom the Upper Ladinian to Carnian of Peninsular Malaysia
by Vachard (Fontaine et al., 1988) is diagnostic in its thickagglutinated wall and planispirally to plectospirally coiled
early stage continued by biserially to nearly uniserially uncoiled second stage with an abrupt change of coiling. The
present materials are closely similar to the Malaysian ones,
but the former seem to have smaller tests and a more
distinguishable early stage than the latter.
Other foraminifers are rather poorly oriented and sufficientnumbers of materials are not prepared. However, they areillustrated herein so that they can be compared with theTriassic fauna of other regions and the entire aspect of thepresent fauna shown. Although specific and generic identifications are difficult, they resemble materials described orillustrated from Triassic limestones in many places of the
Tethyan Realm.
As mentioned above, the conglomeratic limestone of the
Kaizawa Formation consists of Upper Permian as well as
Anisian pebbles. The Anisian fauna is quite distinctive, andis easily distinguished from the Upper Permian one in its
composition. The Anisian foraminifers have smaller tests
and lower frequency of occurrence in comparison with theUpper Permian ones. Limestone lithofacies and composition of other invertebrate fossils are also different between
the Upper Permian and Anisian.
Systematic paleontology
Descriptive remarks based on the materials from the
Kaizawa Formation are given of nine important taxa. The
taxonomic arrangement of the species principally follows theclassification by Loeblich and Tappan (1988), with slight
modification.
Order Foraminiferida Eichwald, 1830
Suborder Textulariina Delange and Herouard, 1896
Superfamily Ammodiscacea Reuss, 1862
Family Ammodiscidae Reuss, 1862
Genus Glomospira Rzehak, 1885

Glomospira densa (Pantie)
Figures 4-3-14

Pilammina densa Pantie, 1965, p.189, pI. 1, figs. 1, 2, pI. 2, figs. 19; Salaj, Biely and Bystricky, 1967, pI. 1, fig.7; Premoli

Figure 5. 1-10. Arenovidalina amy/ovo/uta Ho, 1: Loc.29, 02-02874a, 2: Loc.20, 02-13204, 3: Loc.lO, 02-02924a,
4: Loc.21, D2-13185, 5: Loc.23, 02-02885, 6: Loc.21, 02-13184, 7: Loc.10, D2-02921c, 8: Loc.11, 02-13277a, 9: Loc.
15, 02-13246, 10: Loc.lO, D2-02925b, 1-3= X1OO; 4-6= X120; 7-10= X 80. 11-18. Meandrospira dinarica KochanskyOevide and Pantie, 11: Loc. 11,02-13278,12: Loc.12, 02-13299,13: Loc. 27, 02-02946b, 14: Loc. 29, 02-02874b, 15: Loc.
1, 02-02951c, 16: Loc.lO, 02-02920b, 17: Loc.11, 02-13277b, 18: Loc.27, 02-02947b, X120. 19-21. "Meandrospira"deformata Salaj, 19: Loc.lO, 02-02924b, 20: Loc.12, 02-13300, 21: Loc.20, 02-13208, X 80. 22. Austrocolomia ct.
marschalli Oberhauser, Loc. 10, 02-02926e, x80. 23. Austroc%mia sp., Loc. 21, 02-13180, xBO. 24,25. Cryptoseptida?
sp., 24: Loc.lO, 02-02922,25: Loc.12, 02-02869c, xBO. 26,27. Nodosaria expolita Trifonova, 26: Loc.12, 02-02868b,
27: Loc. 11, 02-13279a, X 100. 28-30. Nodosaria spp., 28: Loc. 27, 02-02948a, 29: Loc. 27, 02-02949c, 30: Loc. 11,0213279b, x BO. 31-36. Diplotremina astrofimbriata Kristan-Tollmann, 31 : Loc.27, 02-02948b, 32: Loc.10, 02-02920c, 33 :Loc.12, 02-02869d, 34: Loc.12, 02-02866c, 35: Loc.12, 02-02870, 36: Loc.1, 02-02953, X 80. 37,38. Diplotreminasp., 37: Loc. 27, D2-02947c, 38: Loc. 27, 02-02947d, x BO.

1018. Anisian foraminifers from Kaizawa, Japan

535

Fumio Kobayashi

536

Silva, 1971, p. 325, 326, pI. 21, figs. 1-3, pI. 22, figs. 3, 4.
Zaninetti, 1969, p.27-29, pI. 4,
figs. A, B, C.
Glomospira densa (Pantie). Bronnimann et al., 1973a, p.307,
308, figs. 1-7, 10, 11; Bronnimann et al., 1973b, p.466, pI. 47,
figs. 3, 4; Gaidzicki et al., 1975, pI. 2, figs. 5-9; Zaninetti,
1976, p.89-91, pI. 2, figs. 17, 21 ; Gaidzicki and Smit, 1977,
pI. 3, figs. 4-9; Trifonova, 1978a, pI. 2, fig. 3; He, 1984, p.
422, pI. 1, figs. 1-7.

Glomospira ct. densa (Pantie).

Descriptive remarks.-Although Pantie (1965) proposed a
new genus Pilammina with P. densa from the Anisian ofMontenegro as the type species, it is considered generally to
be a junior synonym of G/omospira Rzehak. The present
species has been described or illustrated from various
regions of the Tethyan Realm, and is one of the most reliableindicators of an Anisian age. The present materials are
identical with them. Compared with the specimens found inalgal limestone, those contained in ooid grainstone have asmaller test and a rather irregular test outline. These
differences are evidently due to abrasion of the outer test.
Occurrence.-Common to rare at Locs. 15 and 31, and rareat Locs. 1, 10, 12, 13, 14 (?), 20,21,23,27,29, and 30.

Malayspirina fontainei Vachard in Fontaine et al., 1988, p. 157, 158,
figs. 5a-d, i, j, 0, figs. 6e, h.
Descriptive remarks.-Generic identification of Malayspirina requires longitudinal sections, because its chambers arecoiled nearly planispirally in the early stage, then uncoiled
and arranged linearly in the second stage. A randomly cut
section of this genus is similar to that of Earlandinita, Endothyranella or Endothyra, depending on the orientation of thesection.
The present materials closely resemble the following forms
illustrated from West and Southeast Asia: Endothyranella sp.
associated with Meandrospira pusi/la (He) and others from theAnisian of Pakistan (Zaninetti and Bronnimann, 1975); Endothyranella sp. from the Carnian to Norian of Turkey (Altiner
and Zaninetti, 1981); Earlandinita soussii Salaj, E. cf. soussii
Salaj and E. ? sp. from the Anisian to Ladinian of Peninsular
Malaysia (Gaidzicki and Smit, 1977). These forms closely
resemble Malayspirina fontainei newly proposed by Vachard(Fontaine et al., 1988) from the Ladinian to Carnian of
Peninsular Malaysia. The present materials have, however,a smaller test and more distinctive early stage than theoriginal ones of Malayspirina fontainei.
Occurrence.-Rare at Locs.10, 12 and 27.

Genus Glomospirella Plummer, 1945

Glomospirella irregularis (Moeller)
Figures 4-17,18
G/omospirella irregularis (Moeller). Ho, 1959, p. 398, 412, pI. 4,
figs. 14-23; Bronnimann et al., 1975, p.10, pI. 3, figs. 7-10,

Suborder Fusulinina Wedekind, 1937
Superfamily Endothyracea Brady, 1884
Family Endothyridae Brady, 1884
Subfamily Endothyrinae Brady, 1884
Genus Endothyra Phillips, 1846

12-14,16,18.

"Endothyra" cf. kuepper; Oberhauser
Descriptive remarks.- The present specimens are char-acterized by a thick biumbonate test consisting of an undivided tubular chamber streptospiral in the early stage andlater becoming planispirally enrolled. They are similar to
G/omospirella irregularis (Moeller) described from the Anisianof southern Sichuan (Ho, 1959) and eastern Burma (Bronnimann et al., 1975) in size and morphology of the test. The
amount of material is insufficient for thorough comparison
with previous descriptions of the species.
Occurrence.-Rare at Locs.1O (?), 12 and 27.
Superfamily Lituolacea de Blainville, 1827
Family Lituolidae de Blainville, 1827
Subfamily Ammomarginulinae Podobina, 1978
Genus Malayspirina Vachard, 1988

Malayspirina ct. fontainei Vachard
Figures 4-2D--22
Compared.Endothyranella sp.

Zaninetti and Bronnimann, 1975, pI. 35, figs.

13-15.
Earlandinita? sp. Gaidzicki and Smit, 1977, pI. 7, figs. 6, 9.
Earlandinita cf. soussii Salaj. Gaidzicki and Smit, 1977, pI. 7, fig.
7.
Earlandinita soussii Salaj. Gaidzicki and Smit, 1977, pI. 7, fig. 8.
Endothyranella sp. Altiner and Zaninetti, 1981, pI. 85, figs. 4-8.

Figures 4-27-31
Compared.Endothyra kuepperi Oberhauser, 1960, p.16, pI. 3, figs. 7, 14, 22 ;Gaidzicki and Zawidzka, 1973, pI. 1, fig. 14; Zaninetti,1976,
p. 126, 127, pI. 8, figs. 20-25; Gaidzicki and Smit, 1977, pI. 8,
figs. 7, 8; Trifonova, 1978b, pI. 2, fig. 8.
Neoendothyra kuepperi (Oberhauser). Salaj et al., 1967, pI. 1, fig.
11.
"Endothyra" kuepperi Oberhauser.

Zaninetti, 1969, p. 41-43, fig.
7, pI. 6, fig. c.
"Endothyra" aft. kuepperi Oberhauser. Premoli Silva, 1971, p.
337, pI. 27, fig. 4.
Endothyra malayensis Gaidzicki and Smit, 1977, p.324, pI. 8, figs.
1-3.
Endothyranefla ? sp. Gaidzicki and Smit, 1977, pI. 8, figs. 4, 5.
Endothyranefla sp. Gaidzicki and Smit, 1977, pI. 8, fig. 9.
Descriptive remarks.-Endothyra keupperi was originallyproposed for "Endothyra" characterized by having a calcareous agglutinated wall, plectospirally coiled inner whorls andnearly planispirally coiled last whorl from the Carnian of theEastern Alps (Oberhauser, 1960). Triassic species assigned
to Endothyra, including this species, by previous authors can
not be easily distinguished from Late Paleozoic ones by theirmorphologic differences except for the composition andthickness of the wall. The wall of the former group is muchthicker than that of the latter in comparison with test size,

1018.

Anisian foraminifers from Kaizawa, Japanand is composed of calcareous aggulutinated materials
instead of microgranular calcite. Although the genericassignment of this species is uncertain, it is tentatively
included in "Endothyra" with a query as most previous
authors have done.
Four forms described or illustrated from the Anisian to
Ladinian of Peninsular Malaysia by Gatdzicki and Smit
(1977), Endothyra kuepperi, E. ma/ayensis Gatdzicki and Smit,
Endothyranel/a sp. and E.? sp. resemble each other. They
are thought to be conspecific, because the last whorl of "E."kuepperi expands rapidly as compared with the inner ones,
and is not completely coiled planispirally. Therefore, alesser number of chambers in the last whorl and seemingly
uncoiled or evolute terminal chamber as shown in excentric
sections of the Malaysian forms may be ascribed to different
orientations of thin sections.
Occurrence.-Common to rare at Loc.10, and rare at Locs.
12,14 (?), and 27.

537

Meandrospira dinarica Kochansky-Devide and Pantie
Figures 5-11-18
Meandrospira dinarica Kochansky-Devide and Pantie. Salaj eta/., 1967, pI. 1, figs. 13a, 19; Bronnimann et a/., 1973a, p. 313,
314, pI. 20, figs. 8, 11, 12; Bronnimann et a/., 1973b, p. 469, pI.
46, figs. 11, 15, pI. 47, fig. 10; Gatdzicki et a/., 1975, pI. 9, figs.

5-9; Zaninetti, 1976, p.133-135, pI. 1, figs. 12-14 ; Gaidzicki
and Smit, 1977, pI. 4, fig.7; Trifonova, 1978a, pI. 2, fig. 7;
He, 1984, p. 427, pI. 3, figs. 4-9.
Meandrospira? dinarica Kochansky-Devide and Pantie.
Zaninetti, 1969, p. 47-49, pI. 4, figs. E, F.
Citaella dinarica (Kochansky-Devide and Pantie). Premoli Silva,
1971, p. 324, pI. 20, figs. 2, 4-8.

Suborder Involutinina Hohenegger and Piller, 1977
Family Involutinidae Butschli, 1880
Genus Arenovida/ina Ho, 1959

Descriptive remarks.-Zigzag bends of the tubular second
chamber are not so markedly recognizable in the present
materials as in previously described ones. However, they
are closely similar to the European materials and safely
identified with this species in many respects, though very few
completely axial and equatorial sections were prepared.
Occurrence.-Common to rare at Loc.10, and rare at Locs.
1,11,12,13 (?), 23,27, and 29.

Arenovida/ina amy/ovo/uta Ho"Meandrospira" deformata Salaj

Figures 5-1-10

Figures 5-19-21

Arenovidalina amy/ova/uta Ho, 1959, p. 401, 415, 416, pI. 7, figs. 10-

Meandrospira deformata Salaj. Salaj et a/., 1967, p. 122, pI. 2, figs.

3a-3d.

17.
Ophtha/midium?

amy/ova/uta (Ho).

Zaninetti, 1976, p. 141, pI. 3,

deformata Salaj.

Gaidzicki et a/., 1975, p. 290,

pI. 7, figs. 9-16.

figs. 12, 13.
Au/otortus amy/avo/uta (Ho).

Meandrospira?

Lin and Zheng, 1978, p.48, pI. 10,

figs. 28, 29.
Descriptive remarks.-Ho (1959) erected the genus
Arenovida/ina from the Anisian of southern Sichuan, anddiscriminated four species by slight differences in test sizeand shape and degree of expansion of the second tubularchamber. However, comparison of their corresponding
whorls indicates that the significant differences which Ho(1959) insisted on are not clear among the four Chinese
forms. Smaller forms like Arenovidalina chia/ingchiangensis
may merely represent incomplete or immature specimens oflarger forms like A. amy/ova/uta. Au/otortus chialingchiangensis (Ho) and A. amy/ova/uta (Ho), described from the Lower
Triassic of Hubei by Lin and Zheng (1978), closely resemble
each other, and are hardly distinguishable by slight differences in their size and shape of tests.
The present materials are tentatively assigned to A.
amy/ova/uta until the validity of the four Chinese species is
examined in the type locality.
Occurrence.-Rare at Locs.1, 10, 11, 15-17, 20-23, and 29.

Suborder Miliolina Delage and Herouard, 1896
Superfamily Cornuspiracea Schultze, 1854
Family Cornuspiridae Schultze, 1854
Genus Meandrospira Loeblich and Tappan, 1946

"Meandrospira" deformata Salaj.

Zaninetti, 1976, p.138, pI. 1,
figs. 20-22; Resch, 1979, pI. 4, fig. 20.

Descriptive remarks.- The present materials are common
in appearance to the originally and subsequently describedones in a meandrospiral COiling restricted to inner whorls,
followed by irregular coiling in outer ones. Detailed reconstruction of test characters needs more specimens.
Occurrence.-Rare at Locs. 10, 12, and 20.

Suborder Lagenina Delage and Herouard, 1896
Superfamily Robuloidacea Reiss, 1963
Family Ichthyolariidae Loeblich and Tappan, 1986
Genus Austroc%mia Oberhauser, 1960

Austroc%mia cf. marschalli Oberhauser
Figure 5-22
Compared.Austroc%mia marschalli Oberhauser, 1960, p.38, pI. 1, figs. 42-

46,52.
? Austroc%mia marschalli Oberhauser. Trifonova, 1978b, pI. 3,
fig. 4.
? Austroc%mia aft. marschalli Oberhauser. Fontaine et a/.,1988, fig. 5q.
Descriptive remarks.-A few distinctive specimens
obtained have straight sutures, with distinct abrupt shoulders
perpendicular to the long axis of an elongate test with morethan 6 chambers. The upper surface of each chamber isFumio Kobayashi

538

smooth and domed posteriorly. From these features, they
are possibly referable to this species, but have smaller andslenderer tests in comparison with the type material from theCarnian of the Eastern Alps (Oberhauser, 1960). Abrupt
shoulders diagnostic to the original materials are indistinct orabsent in single specimens illustrated from Bulgaria(Trifonova, 1978b) and Peninsular Malaysia (Fontaine et a/.,1988). Further examination of more materials are necessary
to exactly identify them with the original ones.
Occurrence.-Rare at Loc.10.
Superfamily Duostominacea Brotzen, 1963
Family Duostominidae Brotzen, 1963
Genus Diplotremina Kristan-Tollmann, 1960

Diplotremina astrofimbriata Kristan-Tollmann
Figures 5-31-36
Diplotremina astrofimbriata Kristan-Tollmann, 1964, p. 64, 65, pI.

14, figs. 1-4; Premoli Silva, 1971, p. 340, 341, pI. 27, figs. 1, 5,
6, pI. 28, figs. 1,2; Gaidzicki et a/., 1975, pI. 6, figs. 4-7 ;Zaninetti, 1976, p. 186, 187, pI. 17, fig. 5; Gaidzicki and Smit,
1977, pI. 10, fig. 9; He, 1984, p.426, pI. 4, figs. 1-7; Skoutsis-Coroneou et a/., 1990, pI. 2, figs. 11, 12.

Descriptive remarks.-Several horizontal and oblique sections and an oblique vertical section are obtained. Althoughdetails of test construction and the test characters are
unknown because of insufficient numbers of individuals andno free specimens, such structural patterns as convex spiralside, opposite side with deeply lobed umbilicus, chambers
gradually increasing in size, fimbriated sutural end toward
umbilicus and calcareous finely granular wall seem to be
essentially the same as those of the type material from theLadinian of the East Alps (Kristan-Tollman, 1964). However,
it is difficult to compare apertural characters between thetwo.
The general aspects of the present materials closely
resemble the illustrations shown by Gaidzicki et a/. (1975)
from the IIlyrian (upper Anisian) of the Muschelkalk of southern Poland. Diplotremina sp. in this paper is distinguishedfrom the present species by having more chambers and theindistinctive fimbriated suture of the former.
Occurrence.-Rare at Locs.1,12,13 and 27.

References cited
Altiner, D. and Zaninetti, L., 1981: Le Trias dans la region de
Pinarbasi, Taurus oriental, Turqui: unites lithologiques,micropaleontologie, milieux de depot. Rivista !taliana
di Paleontologia e Stratigrafia, vol. 86, no. 4, p. 705-738,
pis. 78-88.
Bronnimann, P., Cadet, J.-P. and Zaninetti, L., 1973a: Sur lapresence d'involutina sinuosa pragsoides (Oberhauser)(Foraminifere) dans I'Anisien superieur probable deBosnie-Herzegovine meridionale (yougoslavie). Rivista !taliana di Paleontologia e Stratigrafia, vol. 79, no. 3, p.
301-323, pis. 19-24.
Bronnimann, P., Cadet, J.-P. and Zaninetti, L., 1973b: Sur
quelques foraminiferes de l'Anisien (Trias moyen) deBosnie-Herzegovine meridionale, Yougoslavie. Rivista
Italiana di Paleontologia e Stratigrafia, vol. 79, no. 4, p.
461-472, pis. 46-48.
Bronnimann, P., Whittaker, J.E. and Zaninetti, L., 1975:
Triassic foraminiferal biostratigraphy of the KyaukmeLongtawkno area, northern Shan States, Burma. Rivista !taliana di Paleontologia e Stratigrafia, vol. 81, no. 1, p.
1-22, pis. 1-3.
Fontaine, H., Khoo, H.P. and Vachard, D., 1988: Discovery ofTriassic fossils at Bukit Chuping, in Gunung Sinyum
area, and at Kota Jin, Peninsular Malaysia. Journal ofSoutheast Asian Earth Sciences, vol. 2, nos. 3/4, p. 145162.
Gaidzicki, A. and Smit, O.E., 1977: Triassic foraminifersfrom the Malay Peninsula. Acta Geologica Polonica,
vol. 27, no. 3, p. 319-332, pis. 1-10.
Gaidzicki, A., Trammer, J. and Zawidzka, K., 1975: Foraminifers from the Muschelkalk of southern Poland.
Acta Geologica Polonica, vol. 25, no. 2, p.285-298, pis.
1-12.
Gaidzicki, A. and Zawidzka, K., 1973: Triassic foraminifer
assemblages in the Choc nappe of the Tatra Mts. Acta
Geologica Polonica, vol. 23, no. 3, p.483-490, pis. 1-6.
Goto, H., 1986: Reconsideration of the Permian Tatsuno
Group in the southern part of the Kozuki-Tatsuno Belt,
Hyogo Prefecture, Southwest Japan. Journal of theGeological SOCiety of Japan, vol. 92, no. 9, p. 663-674.
(in Japanese with English abstract)

He, Y., 1984: Middle Triassic foraminifera from central andsouthern Guizhou, China. Acta Palaeontologica Sinica,
vol. 23, no. 4, p.420-431, pis. 1-4. (in Chinese andEnglish)Acknowledgments
I would like to express my cordial thanks to Dr. Koichiro
Ichikawa, Professor Emeritus of Osaka City University, Dr.
Hisayoshi Igo, Professor of the University of Tsukuba and Dr.
Tomowo Ozawa, Associate Professor of Nagoya University
for their critical reading of the manuscript. Deep appreciation is due to Dr. Chikao Kurimoto, Geological Survey ofJapan for his kind cooperation in collecting the literature on
foraminifers. A part of this study was financially supported
by a Grant-in Aid for Scientific Research (C) of the Japanese
Ministry of Education, Science and Culture (Project No.
05640521).

Ho, Y., 1959: Triassic foraminifera from the Chialingkiang
Limestone of south Szechuan. Acta Pa/aeont%gica
Sinica, vol. 7, no. 5, p. 387-418, pis. 1-8. (in Chinese andEnglish)Ichikawa, K. and Kudo, A., 1951 : Triassic formations in thesoutheastern part of the Kanto Mountains. In, Geological Survey of Japan ed., Triassic stratigraphy of Japan,
Report of the Geological Survey of Japan, spec. no., p.
26-32. (in Japanese)

Kobayashi, F. and Ozawa, T., in press: Stratigraphy of the
Nishitama Group (uppermost Permian to Triassic) in the
Iwai-Kanyo area, southeast Kwanto Mountains, Japan.
Humans and Nature, no. 6.
Kristan-Tol/mann, E., 1964: Die Foraminiferen aus den
rhatischen Ziambachmergein der Fischerwiese bei
Aussee im Salzkammergut. Jahrbuch der Geologi-

1018.

Anisian foraminifers from Kaizawa, Japanschen Bundesanstalt, Sonderband 10, p. 1-182, pis. 1-39.
Kristan-Tollmann, E., 1991: Triassic Tethyan microfauna in
Dachstein limestone blocks in Japan. Saito Ho-on Kai
Special Publication, no. 3 (Proceedings of Shallow Tethys 3, Sendai, 1990), p. 35-42, pis. 1-4.
Lin, J.X. and Zheng, Y.M., 1978: Triassic foraminifers. In,
Hubei Institute of Geological Sciences ed.,
Paleontological Atlas of Central South China, no. 4 (Microfossils), p. 43-49, pis. 9, 10. Geological Publishing
House, Beijing. (in Chinese)
Loeblich, AR.Jr. and Tappan, H., 1964: Sarcodina, chiefly''Thecamoebians'' and Foraminiferida. In, Moore, R.C.
ed., Treatise on Invertebrate Paleontology, Protista 2, pt.
C, 900+31 p. Kansas University Press, Lawrence.
Loeblich, A.R.Jr. and Tappan, H., 1988: Foraminiferal Genera
and their Classification. 970 p., 847 pis. Van Nostrand
Reinhold, New York.
Naumann, E., 1881: Ober das Vorkommen von Triasbildungen im nord lichen Japan. Jahrbuch der Kaiserlichen
K6niglichen Geologischen Reichsansta!t, vol. 31, p. 519528.
Naumann, E., 1885: Uber den Bau und die Entstehung derjapanischen Inseln. 91 p. R. Friedlander und Sohn,
Berlin.
Oberhauser, R., 1960: Foraminiferen und Mikrofossilien<incertae sedis> der ladinischen und karnischen Stufe
der Trias aus den Ostalpen und aus Persien. Jahrbuch
der Geologischen Bundesanstalt, Sonderband 5, p.546, pis. 1-6.
Ozawa, T. and Hayami, 1.,1969: Triassic Oxytoma bed in thesuburbs of Ome City, Kwanto Mountains. Transactions
and Proceedings of the Palaeontological SOCiety ofJapan, New Series, no. 73, p.32-40, pI. 3.
Ozawa, T. and Kobayashi, F., 1986: Stratigraphy and geologic structure of the Paleozoic and Mesozoic strata inthe southern part of the Kwanto Mountains, central
Japan. Bulletin of Hyogo University of Teacher Education, vol. 6, p.103-141. (in Japanese with English
abstract)
Pantie, S., 1965: Pilammina densa n. gen., n. sp. and otherAmmodiscidae from the Middle Triassic in Crmnica(Montenegro). Geoloski Vjesnik, vol. 18, no.1, p.189193.
Piller, w.E., 1983: Remarks on the suborder Involutinina
Hohenegger and Piller, 1977. Journal of Foraminiferal
Research, vol. 13, no. 3, p.191-201.
Premoli Silva, I., 1971: Foraminiferi anisici della regione
giudicariense (Trento). Rivista Italiana di Paleontologia
e Stratigrafia, vol. 77, no. 3, p. 303-351, pis. 19-30.
Resch, w., 1979: Zur Fazies-Abhangigkeit alpiner Trias-

Foraminiferen. Jahrbuch der Geologischen Bundesansta!t, vol. 122, no. 1, p. 181-240, pis. 1-5.
Sakai, A, 1987: Geology of Itsukaichi District. 75 p., geological sheet map at 1 : 50,000. Geological SUNey ofJapan. (in Japanese with English abstract)
Salaj, J., Biely, A and Bystricky, J., 1967: Trias Foraminiferen in den Westkarpaten. Geologicke Prace, vol. 42, p.
119-136, pis. 1-8.
Skourtsis-Coroneou, V., Trifonova, E. and Tselepidid, V.,
1990: Foraminifera sequences from the Anisian (Hallstatt faCies) of the Epidaurus area, Peloponnesus(Greece). In, Takayanagi, Y. and Saito, T. eds., Studies
in Benthic Foraminifera (Proceedings of the Fourth International Symposium on Benthic Foraminifera, Sendai,
1990), p.361-367. Tokai University Press, Tokyo.
Takagi, Z., 1944: A new find of Pseudomonotis ochotica
from northwest of Ome-machi and its neighboring
geology. Journal of the Geological SOCiety of Japan,
vol. 51, no. 609, p.196-198. (in Japanese)
Takashima, K. and Koike, T., 1984: Stratigraphy and geological structure of the Mesozoic strata in the
Gozenyama-Itsukaichi area, southeastern part of the
Kanto Mountains. Science Reports of the Yokohama
National University, Section II, no. 31, p.29-49. (inJapanese with English abstract)
Trifonova, E., 1978a: The foraminifera zones and subzonesof the Triassic in Bulgaria. I. Scythian and Anisian.
Geologica Balcanica, vol. 8, no. 3, p.85-104, pis. 1-4.
Trifonova, E., 1978b: The foraminifera zones and subzonesof the Triassic in Bulgaria. II. Ladinian and Carnian.
Geologica Balcanica, vol. 8, no. 4, p.49-64, pis. 1-5.
Zaninetti, L., 1969: Les foraminiferes du Trias de la region
de l'Almtal (Haute-Autriche). Jahrbuch der Geologischen Bundesanstalt, Sonderband 14, p.1-155, pis. 1-12.
Zaninetti, L., 1976: Les foraminiferes du Trias. Essai desynthese et correlation entre les domaines mesogeens
europeen et asiatique. Rivista Italiana di Paleontologia
e Stratigrafia, vol. 82, no. 1, p. 1-258, pis. 1-24.
Zaninetti, L. and Bronnimann, P., 1975: Triassic foraminiferafrom Pakistan. Rivista !taliana di Paleontologia e Stratigrafia, vol. 81, no. 3, p. 257 -280, pis. 31-36.
Zaninetti, L. and Baud, A., 1972: Essai de zonation d'apres
les Foraminiferes dans l'Anisien moyen et superieur desPrealpes medianes rigides (Prealpes romandes, Suisse,
et Prealpes du Chablais, France). Eclogae Geologicae
Helvetiae, vol. 65, no. 2, p. 343-353.
Zhang, L.x., 1939: Some new facts concerning the Triassic
formations at Iwai near Itsukaichi, Province of Musashi.
Journal of the Geological Society of Japan, vol. 46, no.
546, p. 113-116. (in Japanese)m,

Arai AA':J:l:, Guizhou jHI'i, Hubei fii/J:lt, Itsukaichi Ii B
Kaizawa JR tR, Kanyo JlfJ!, Kayakubo ~Kozuki -.t.fj, Nishitama g§~~, Oguno *~lI!f, Ome wffij, Sichuan IZ!3JII, Tatsuno ~lI!f

m,

539

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp. 540-543, 1 Fig., September 30, 1996
© by the Palaeontological Society of Japan 1996

SHORT NOTES

A little known species of Inoceramus (Bivalvia)
from the Turonian (Cretaceous) of Hokkaido
TATSURO MATSUMOTO
c/o Department of Earth and Planetary Sciences, Kyushu University 33, Fukuoka, 812-81 Japan

Received 10 January 1996; Revised manuscript accepted 20 May 1996

Inoceramus kamuy Matsumoto and Asai has been recently
established on a number of specimens from the Lower
Turonian of Hokkaido (Matsumoto and Asai, 1996). Thereis, furthermore, another little known species from the lower
part of the Turonian in Hokkaido. A short note is given here
on it.

Paleontological description
Genus Inoceramus Sowerby, 1814
Type species.-Inoceramus cuvierii Sowerby, 1814.
Inoceramus aft. I. tuberosus Keller, 1982

Figures 1 A-F
Material.- The description below is based primarily on GK.
H8320 collected by K. Tanabe, H. Hirano and T.M. in 1973
from the siltstone exposed at loc. R4519 in the lower courseof the Nakakinenbetsu River of the Obira [Obirashibe] area,
northwestern Hokkaido. GK. H8320 is a medium-sizedindividual of conjoined left and right valves. It is associatedwith several imperfect smaller (probably young) shells.
There are also a few other specimens which are referable tothis species.
Repositories of the described speCimens are as follows:
GK= Type Room, Department of Earth and Planetary
Sciences, Kyushu University, Fukuoka 812-81
IGPS = Institute of Geology and Palaeontology, Tohoku
University, Sendai 980-77
Terminology.-For the terms to describe morphologicalcharacters and their abbreviations, I follow generally those ofrecent papers, except for ,B=beak angle or apical angle
instead of angle of umbonal inflation (see Matsumoto andAsai, 1996, table 1).
Description.- The shell is medium-sized, ineqilateral andsomewhat inequivalve, with the left valve more inflated than
the right. The beak is prosogyrous; the left beak is morestrongly incurved over the hinge line than the right. The
apical angle is less than 90' and may be measured as 85' to
65' in accordance with the curved outline of the apical part.
The growth axis is nearly straight, forming an angle of about
55' with the hinge line, and divides the disk in half. The left
valve is much inflated and the right valve is moderately so.
The umbonal part, which is demarcated by a constriction
from the main part, is especially inflated; hence the left
umbo appears to be hemispherical and the right one domelike in lateral and posterior views. The anterior side of thevalve is steeply inclined, partly vertical to the plane ofcommissure, and is somewhat concave below the umbo.
The anterior margin is, thus, gently sinuous and bent rather
abruptly to the semicircular ventral margin, which in turn
passes to the moderately to gently convex posterior margin.
The hinge line is fairly long, with s/I about 3/4, and forms theangle (y) of 100' (in youth) to 125' (later) with the posterior
margin. The posterodorsal wing is narrow and inclined inyouth, but later it becomes broader and flatter. The anterior
hinge angle (a) is roughly 100', if the sinuosity of the anterior
margin is ignored. The ratio L/H decreases gradually withgrowth in the young stage and becomes nearly constant(about 0.8) in the middle and late growth stages.
The comarginal major ribs are normally moderately strong,but some of them are rather weak. They are more distinct
when associated with deeper grooves which occur at periodic intervals. The grooves are disposed on both the left
and right valves at corresponding positions and accordingly
can be interpreted as marking periodic arrests of growth;hence they can be called constrictions. Some of the majorribs are bifurcated or intercalated. Minor rings are discernible even on some parts of the internal mould. They are

Figure 1. Inoceramus aff. I. tuberosus Keller. GK. H8320 from lac. R4519. A: lateral view of the left valve (LV) withposterodorsal view of the right valve (RV), B: lateral view of RV with posterodorsal view of LV, C: dorsal view of both valves(BV) with LV below, D: dorsal view of BV with LV above, E: anterior view of BV, F: posterior view of BV, with the externalmould of a small RV in a broken part of the nodule. Figures are natural size. Photos by courtesy of M. Noda without
whitening.

1019. A little known species of Inoceramus

541

Tatsuro Matsumoto

542
Table 1.
Valve

h

I/h

H

n

~

~

~

~

~

70

52

.80

25

.45

.36

~

~

~

5

Right

63

55

.87

Linear dimensions are in mm.

Measurements of Inoceramus aft. tuberosus
L

L/H

b

b/I

b/H

s

s/I

y

43
43

.74
.78

125"
125"

55"
55"

Outline of the shell is partly restored.

impressed more clearly on the external mould. On theanterior side they are much crowded and become finelamellae or lirae.
In the last part (with H = 55-75 mm) the major ribs tend to
weaken, the interspaces somewhat broaden and the minor
rings become faint. This probably indicates the adult to oldstage.
IGPS. 22725 from the Obira area (though without apinpointed locality) was described as an example of Inoceramus concentricus var. costatus Nagao and Matsumoto(1939, p.270, pI. 27, fig. 2). It consists of both valves and isdifferent from I. costatus (lectotype [ibid., pI. 24, fig.1J andsome other examples) as redefined by Tamura andMatsumura (1974, p.49) in its more rounded shell shape,stronger and coarser ribs, and distinct posterior wing. It
closely resembles the middle-aged part of the above described GK. H8320 and is probably an example of thisspecies. The ribs are more distinct in the right valve of
IGPS. 22725 than in that of GK. H8320, but this is due to thesecondary abrasion of the latter. Even in the latter the ribs
remain more clearly on the less abraded anterolateral andposterolateral portions. Also the ribs of moderate intensity
are impressed on the external mould of a smaller shell whichis associated with GK. H8320 in the same nodule.
Measurements.-See Table 1.
Comparison and discussion.- The specimens from Hokkaido described above are similar to the holotype of Inoceramus tuberosus Keller (1982, p.69, pI. 2, fig. 5), from theLower Turonian of Germany, in the inflated and roundedvalve and the general configuration of the ornament. One
specimen of Inoceramus striatus Mantell illustrated by Geinitz(1872, p. 41, pI. 13, fig. 10 only) is regarded by Keller as anotherexample of I. tuberosus, but it is also a left valve. Keller has
stressed the knobby shape of the umbonal part. As theanterior or dorsal view was not illustrated, the charactercannot be exactly compared with ours. Geinitz' figure
shows an imperfect preservation of the beak. Even in the
figure of the holotype, a partly eroded state of the knobby
umbo seems to be shown. In our specimens the umbonal
part is much inflated and appears to be hemispherical ordome-like in lateral and posterior views, but the beak ispointed at its apex. In the German papers the apical end is
not shown and I doubt that the knobby feature might havebeen produced secondarily from the much inflated umbonal
part. At any rate, without examining the actual specimens,
I cannot decide the specific identity or difference between
the speCimens from Japan and Germany. Moreover, thenumber of samples in the available material is too small inboth regions to get a proper concept of a species. For thetime being, I have to call our speCies Inoceramus aff. I.
tuberosus or simply I. aff. tuberosus. This means that our

species is closely allied to I. tuberosus, but that, in this case,it mayor may not be identical with I. tuberosus.
I. aff. tuberosus is certainly related with Inoceramus reduncus Pergament from the Middle and Upper Cenomanian of
the Pacific region of Russia and Hokkaido (see Matsumoto
et a/., 1988, p. 383), but the former has more rounded andmore inflated valves than the latter. I. reduncus tends togrow along the growth axis to form a very high outline.
Such a form (morphotype) is commonly found in a fairly highlevel (if not at the top) of the Cenomanian sequence in
Hokkaido, as shown by several examples from the Oyubari
and Ikushunbetsu areas (Nishida et aI., 1993, pI. 6, fig. 3, pI. 7,
fig. 1 ; unfigured specimen from Ikushunbetsu). The
younger part of this morphotype resembles I. aff. tuberosus inshell shape but has much weaker ornament. In later growthstages I. reduncus has smaller ratios of L/H and b/H thanthose of I. aff. tuberosus, although there is some variation
within the species.
I interpret that I. aff. tuberosus of a later geological age isprobably a descendant of I. reduncus. As described above,
GK. H8320 has the characters of the adult stage. It is nota young shell of I. reduncus. I. aff. tuberosus may be so to
speak a relict of the I. reduncus group.
Occurrence.- The siltstone exposed at loc. R4519 is referred to Member Mj (Lower Turonian) by Tanaka (1963), but
Tanabe et a/. (1977) referred it to "Mjk", because Members Mj
and Mk are hardly discriminated in that portion of the Obiraarea. A fairly well-preserved ammonite occurred in thesame stratum. It is identified with Damesites laticarinatus
Saito and Matsumoto, which is rather long-ranging from late
Cenomanian to somewhere in mid-Turonian. More accurate
age indicators (ornate ammonites or MytiJoides) were notfound there. Hence, the siltstone of loc. R4519 is either
Lower Turonian or early Middle Turonian.
The rare occurrence of I. tuberosus in the Lower Turonianof Germany and that of I. aff. tuberosus in the lower part of
the Turonian in Hokkaido is in high contrast to the abundance of Mytiloides spp. The group of I. reduncus may
have declined in early Turonian time for environmental
reasons. In fact, there was a marked event (the so-called
OAE) at the end of the Cenomanian, as is observed on the
excellent outcrops along the Shirakin River [= HakkinzawaJ route of the Oyubari area (see Hasegawa, 1995;
Toshimitsu et a/., 1995, fig. 1). Also in the Taki-no-sawaroute I observed the black mudstone above the I. nodai bed
and not far below the bed with Pseudaspidoceras flexuosum
Powell (see route map of Nishida et a/., 1993, fig. 5).

Acknowledgments
I thank Drs. Kazushige Tanabe and Hiromichi Hirano for1019.

A little known species of Inoceramus

their cooperation with me in field work, Dr. Masayuki Noda
for his fine photography and valuable discussion on relevant
inoceramids, Drs. Ireneusz Walaszczyk 0/Varsaw) and Haruyoshi Maeda (Kyoto) for their kind information about Geinitz'
paper, and Dr. Kunihiro Ishizaki and Miss Kazuko Mori for
their help in preparing the manuscript.
References cited

Geinitz, H.B., 1872: In Geinitz, H.B., 1872-75: Das Elbthalgebirge in Sachsen. Teil 2. Der mittlere und obere
Quader. Palaeontographica, vol. 20, p.1-245, pis. 1-46
[p.1-52, pis. 1-13, 1872]'
Hasegawa, T., 1995: Correlation of the Cenomanian/Turonian boundary between Japan and Western Interior of
the United States. Journal of the Geological Society ofJapan, vol. 101, p.2-12.
Keller, S., 1982: Die Oberkreide der Sack-Mulde bei Alfeld(Cenoman-Unter Coniac). Lithologie, Biostratigraphie
und Inoceramen. Geologisches Jahrbuch, Reihe A,
Heft 64, p.3-171, pis. 1-8.
Matsumoto, T. and Asai, A., 1996: An early Turonian(Cretaceous) new species of Inoceramus (Bivalvia) from
Hokkaido. Transactions and Proceedings of the
Palaeontological Society of Japan, New Series, no. 181,
p.375-387.
Matsumoto, T., Asai, A., Hirano, H. and Noda, M., 1988:
Some inoceramids (Bivalvia) from the Cenomanian(Cretaceous) of Japan-III. Transactions and Proceedings of the Palaeontological Society of Japan, New

543

Series, no. 149, p. 378-395.
Nagao, T. and Matsumoto [Matumoto], T., 1939: A monograph of the Cretaceous Inoceramus of Japan. Part I.
Journal of the Faculty of Science, Hokkaido University,
series IV, vol. 4, p.241-299, pis. 23-34.
Nishida, T., Matsumoto, T., Maiya, S., Hanagata, S., Yao, A.
and Kyuma, Y., 1993: Integrated mega- and microbiostratigraphy of the Cenomanian Stage in the Oyubariarea, Hokkaido-with special reference to its upper andlower limits-Part 1. Journal of the Faculty of Education, Saga UniverSity, vol. 41, no. 1, part 2, p.11-57. (inJapanese with English abstract)
Tamura, M. and Matsumura, M., 1974: On the age of the
Mifune Group, central Kyushu, Japan, with a descriptionof ammonite from the group by T. Matsumoto. Memoirof the Faculty of Education, Kumamoto UniverSity, vol.
23, section 1, p. 17-56, pI. 1.
Tanabe, K., Hirano, H., Matsumoto, T. and Miyata, Y., 1977 :Stratigraphy of the Upper Cretaceous deposits in the
Obira area, northwestern Hokkaido. Science Report of
the Department of Geology, Kyushu University, vol. 12,
no. 3, p. 181-202. (in Japanese with English abstract)
Tanaka, K., 1963: A study on the Cretaceous sedimentationin Hokkaido, Japan. Report of the Geological Surveyof Japan, no. 197, p.1-122, pis. 1-3, maps 1-2.
Toshimitsu, S., Matsumoto, T., Noda, M., Nishida, T. andMaiya, S., 1995: Towards an integrated mega-, microand magneto-stratigraphy of the Upper Cretaceous in
Japan. Journal of the Geological Society of Japan, vol.
101, p. 19-29. (in Japanese with English abstract).

Hakkin-zawa B~iR, Hokkaido ~tWJ![, Nakakinenbetsu cjJilc;%;lIU, Obira [Obirashibe] 'PF [;t t:"'7 S/~], Oyubari 7;:57.&, Shirakin B~, Taki-no-sawa r.gO)iR.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp. 544-546, 1 Fig., September 30, 1996
© by the Palaeontological Society of Japan 1996

SHORT NOTES

Triassic aulacocerid (Mollusca: Cephalopoda) from thecentral Oman Mountains
SHWI NIKO\ ALAIN PILLEVUIT2 and TAMIO NISHIDA3
lDepartment of Environmental Studies, Faculty of Integrated Arts and Sciences, Hiroshima University,
Higashihiroshima, 724 Japan
21nstitute of Geology and Paleontology, University of Lausanne, BFSH 2, 1015 Lausanne-Dorigny, Switzerland
3Department of Earth Science, Faculty of Education, Saga University, Saga, 840 Japan

Received 3 December 1995; Revised manuscript accepted 10 May 1996

The aulacocerid cephalopod species Atractites arabicus
sp. nov. was discovered from a limestone conglomerate
exposed in the "Rustaq Ouest" area, approximately 5 km
west of Rustaq village, central Oman Mountains. This area
is characterized by the presence of the thrust sheets, called
Hawasina Nappes, of Tethyan origin formed during the Late
Cretaceous obduction of ophiolite complex onto the Arabiancontinental margin (e.g., Robertson and Searle, 1990). The
limestone conglomerate overlies siliciclastic sequences
containing Halobia, and is situated in the basal portion of the
Hawasina Nappes (Pillevuit, 1993).
The specimens studied are deposited in the Paleontological collections of Geological Museum of Lausanne(MGL), Switzerland.
Systematic paleontology
Order Aulacocerida Stolley, 1919
Family Xiphoteuthididae Naef, 1922
Genus Atractites Gumbel, 1861
Type species.-Atractites alpinus Gumbel, 1861.

Atractites arabicus sp. nov.
Diagnosis.-Species of Atractites with nearly symmetricalrostra, position of phragmocone slightly shifts to ventral sidefrom central axis of rostrum; angle of phragmocone expansion approximately 5 degrees.
Description.-Nearly symmetrical rostra of alveolar region
with smooth surface; profile conical to cylindriconical, angleof expansion approximately 2 degrees in apical part ofholotype, paratype exhibits subparallel sides, outline cylindriconical; cross section of rostrum slightly compressed inlateral direction, lateral/dorsoventral ratio of rostrum approximately 0.94; largest speCimen (holotype) attains 12.5 mm indorsoventral rostrum diameter; rostra mostly composed ofcoarse crystal of carbonates caused by recrystallisation, but
mammillary growth pattern partly recognized; alveolus pen-etrates throughout preserved rostrum; phragmocone orthoconic with approximately 5 degrees of angle of expansion,slightly compressed in cross section, slightly shifts venterfrom central axis of rostrum in position, lateral/dorsoventral
ratio of phragmocone approximately 0.93; surface of
conotheca smooth; septa convex adapically with moderately strong curvature; width/length ratio of camerae somewhat variable, ranges from 1.9 to 3.4; siphuncle position at
ventral margin, cylindrical with weak constrictions at septal
neck, small, its maximum diameter/phragmocone diameterin dorsoventral section approximately 0.12; septa of ventral
side of siphuncle very small, low simple mound-like indorsoventral section; septal necks short, 0.49 mm in length
in apical paratype (corresponding dorsoventral diameter ofphragmocone 5.1 mm), prochoanitic with retrochoanitic projections, connected by laminated and well-calcified connecting rings; inner surface of siphuncle coated withorganic membrane (conchiolinic?); no cameral and/or siphuncular deposits detected.
Discussion.-Fischer (1951) reported an aulacocerid possessing a holochoanitic siphuncle from the Norian (Upper
Triassic) of Nevada. He proposed the genus Choanoteuthis
on the basis of its unique siphuncie. In contrast, Jeletzky(1966) stated that Atractites ausseanus (Mojsisovics, 1871) and
Fisher's speCimen have prochoanitic and feebly retrochoanitic septal necks, and that the holochoanitic appearance is caused by strong calcification of the connecting
rings. The connecting rings of the present specimens arealso strongly calcified and layered, thus its structure is apt tomislead. However, detailed observations, mentioned in theabove description, support Jeletzky's view that the genus
Choanoteuthis is regarded as a synonym of the genus
Atractites. The siphuncular tube of the present speCimens
is double-layered (connecting ring and inner layer of organic
membrane), but lacks an intercalated porous prismatic layer
in contrast to belemnoids (Obata et al., 1980) and the apicalshell of Dictyoconites (Bandel, 1985).
Atractites sp. described from the Anisian (Middle Triassic)of Afghanistan by Kummel and Erben (1968) is externally34.

Triassic aulacocerid from Oman

545

I
6

9

3

7

5

11

Figure 1. Atractites arabicus sp. nov. from the Matbat Formation. 1- 5. holotype, MGL 72031 , 1 : dorsal
outline, x 1.5, 2: left profile, x 1.5, 3 : cross section at position indicated by arrow given in 1, x 2, 4: dorsoventral
polished section, venter on left, x 2, 5: external mold of phragmocone showing smooth surface of conotheca, x 2.
6- 11. paratype MGL 72032, 6 : left profile, x 1.5, 7: septal view at position indicated by arrow given in 6, x 1.5, 8 :dorsoventral polished section, venter on right, x 2, 9 : dorsoventral thin section showing siphuncular structure, x 12,
10: details of septal neck and connecting rings, arrow indicating ventral septum, x 50, 11 : longitudinal thin section
showing mammillary growth pattern of rostrum, x 6. 1,2,5- 7, coated with ammonium chloride.

similar to A. arabicus sp. nov., but apparently differs in
distinctly orthochoanitic septal necks, larger apical angle ofphragmocone (6- 9 degrees vs. approximately 5 degrees in A.
arabicus) and centrally located phragmocone. Previously
there were no records of aulacocerids from Arabia (Doyle,1990).
Etymology.- The specific name is derived from Arabia.
Materia/.- The holotype, MGL 72031, is an incomplete
rostrum and phragmocone, 66.6 mm in length. The paratype, MGL 72032, is an incomplete rostrum and ph ragmocone, 33.0 mm in length.
Occurrence and age.-The two specimens were collectedfrom a reddish limestone boulder (up to 2 m in diameter) in alimestone conglomerate bed. The sequence is correlativewith the Unit III of the Matbat Formation in the Hawasina
Window. Based on the associated ammonoids, Krystyn (personal communication) considers the age of the boulder to belate Ladinian to early Carnian.

Acknowledgments
Thanks to Dr. L. Krystyn (University of Vienne) for identification and information of the "Rustaq Ouest" ammonoids.
Dr. P. Doyle (University of Greenwich) read the original manuscript.

References cited
Bandel, K., 1985 : Composition and ontogeny ofDictyoconites (Aulacocerida, Cephalopoda) .
Palaontologische Zeitschrift, vol. 59, p. 223- 244.
Doyle, P., 1990: The biogeography of the Aulacocerida(Coleoidea). In , Paliini, G., Cecca, F., Cresta, S. andSantantonio, M. eds ., Atti del Secondo Convegno Inter-546

Shuji Niko et al.

nazionale, Fossili, Evoluzione, Ambiente, p.263-271.
Editore Comitato Centenario Raffaele Piccinini, Pergola.
Fischer, AG., 1951 : A new belemnoid from the Triassic of
Nevada. American Journal of Science, vol. 249, p.
385-393, pis. 1, 2.
Gumbel, C.W., 1861: Geognostische Beschreibung desbayerischen Alpengebirges und seines Vorlandes.
950 p. Verlag von Justus Perthes, Gotha.
Jeletzky, JA, 1966: Comparative morphology, phylogeny,
and classification of fossil Coleoidea. The Universityof Kansas Paleontological Contributions, Mollusca, Article 7, p.1-162.
Kummel, B. and Erben, H.K., 1968: Lower and Middle
Triassic cephalopods from Afghanistan. Palaeontographica, Abteilung A, vol. 129, p.95-148, pis. 19-24.
Mojsisovics, E. von., 1871: Ueber das Belemnitiden-Geschlecht Aulacoceras Fr. v. Hauer. Abhandlungen derKaiserlich-Koniglichen geologischen Reichsanstalt, vol.
21, p. 41-57, pis. 1-4.

Naef, A, 1922: Die fossilen Tintenfische. 322 p. Verlag
von Gustav Fischer, Jena.
Obata, I., Tanabe, K. and Fukuda, Y., 1980: The ammonite
siphuncular wall: its microstructure and functionalsignificance. Bulletin of the National Science
Museum, Tokyo, Series C (Geology and Paleontology),
vol. 6, p.59-72, pis. 1-3.
Pillevuit, A., 1993: Les blocs exotiques du Sultanat d'Oman.
Memoires de Geologie (Lausanne), no. 17, p.1-249.
Robertson, AH.F. and Searle, M.P., 1990: The northern
Oman Tethyan continental margin: stratigraphy, structure, concepts and controversies. In, Robertson,
A.H.F., Searle, M.P. and Ries, A.C. eds., The Geology
and Tectonics of the Oman Region, p.3-25. Geological Society Special Publication, No. 49.
Stolley, E., 1919: Die Systematik der Belemniten. Jahresbericht des Niedersachsischen geologischen Vereins,vol. 11, p. 1-59. (not seen)

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 183, pp. 547-550,2 Figs., September 30, 1996

© by the Palaeontological Society of Japan 1996
SHORT NOTESPreliminary note on the rediscovery of "Neoschwagerina(Sumatrina) multiseptata Deprat" from Akasaka, JapanZAW WIN and SUMIO SAKAGAMI
Graduate School of Science and Technology, Chiba University, Chiba, 263 Japan
Konakano 48, Akiruno-shi, Tokyo, 190-01 Japan

Received 28 December 1995; Revised manuscript accepted 5 May 1996

Deprat (1912) first introduced and described a new neoschwagerinid species with specialized morphologic characters from the Sisophon Limestone of Cambodia as Neoschwagerina (Sumatrina) multiseptata which was later allocated variously: some workers assigned it to the genus
Yabeina Deprat (1914), and others who follow Lee (1933) to his
genus Lepidolina Lee. In 1914, Deprat further reported theoccurrence of this species from the Akasaka Limestone ofJapan. According to him, this species in the Akasaka camefrom the limestone horizon which is stratigraphically above
the limestone division characterized by Neoschwagerina(Yabeina) globosa (Yabe).
Later, the Akasaka Research Group (1956) reported theoccurrence of a possible specimen of this missing fusulinefrom the Akasaka Limestone in association with Yabeina
igoi. Using the materials collected by the group, Morikawa
and Suzuki (1961) described and conferred that specimen to
Yabeina multiseptata (Deprat). Unfortunately, as their specimen and illustration were not good enough, it was very
difficult to make any clear-cut diagnosis and most fusuline
workers are not convinced of their identification and description. Honjo (1959) also carried out a paleontological study ofthis limestone unit but could not confirm any occurrence ofmultiseptata.
From that time onward, most paleontologists believed that
Deprat (1914) might have described this species based on his
specimens from Cambodia having mistaken them as being of
Akasakan derivation. They concluded that multiseptata
constitutes a fauna or bioseries different from that of Yabeina
globosa and that there is no possibility that multiseptata
occurs together with the Yabeina globosa fauna. Even
though Yamagiwa and Saka (1972) reported the co-occurrence of multiseptata with Yabeina aff. globosa in sandstonelenses within argillaceous rocks exposed along the Toyacoast of the Shima Peninsula, Mie Prefecture, Japan, mostworkers viewed it as an exceptional case.
These situations described above led most fusuline
workers to regard the species multiseptata as a species of
the genus Lepidolina rather than of the genus Yabeina.
These workers believed that Lepidolina and Yabeina respectively occur in different lithofacies on account of theirdifferent ecological traits and, consequently, never occur

together. This way of thinking resulted in the faunal provinciality of Lepidolina and Yabeina.
The so-called "Lepidolina" multiseptata, treated as
Yabeina (Lepidolina) multiseptata in the present article andrepresented by specimens showing sufficient morphologic
features for specific diagnosis, was discovered from an
isolated limestone outcrop in the Akasaka area, the type
locality of the genus Yabeina (Figures 1 and 2). A few
doubtful specimens of multiseptata were also detected fromthe northeastern part of the limestone plateau.
The spirotheca of the present specimens is composed ofa tectum and very thin keriotheca, ranging in thickness from0.01 to 0.03 mm. Secondary transverse septula are short,thin and somewhat irregular in shape, but a few of them areclub-shaped. Generally one, or rarely two, secondary transverse septula are present between the adjacent primary
ones. These secondary transverse septula are seen starting from the third or fourth volution to the outermost one.
Three to five axial septula are present between the adjacentsepta. The largest proloculus noticed among the present
specimens is 0.4 mm in diameter.
This species occurs in the dark gray, massive to poorly
bedded bioclastic micritic limestone that exhibits apparent
nodular structure. Petrographically, this limestone is algalforaminiferal wackestone-packstone composed of abradedbioclasts of dasycladacean algae, fusulines, bryozoans andother unidentifiable shells encased in a micrite matrix.
This species occurs together with Yabeina igoi andYabeina aff. globosa within an approximately 5 cm-thickzone fairly crowded with fusulines. Yabeina igoi which,according to Morikawa and Suzuki (1961), may be synonymous with Y. ozawai of Honjo (1959) is the leading faunal
constituent among the fusulines, and multiseptata follOWS as
the second. A few specimens of Neoschwagerina minoensis are also noted.
On the basis of its fossil assemblage, this Yabeina igoiYabeina (Lepidolina) multiseptata fauna is assignable to theYabeina igoi subzone of Morikawa and Suzuki (1961).
According to them and the present field observation, thissubzone is situated stratigraphically below the Yabeina katoi
and Yabeina globosa subzones.
It is now necessary to reconsider the previous views ofZaw Win and Sumio Sakagami

548

Yabeina Deprat, but now to the genus Lepidolina Lee by
most students. Originally, Lee (1933), using Deprat's illustrations of multiseptata as the type specimen, defined Lepidolina as a new genus almost entirely devoid of keriotheca
in its wall. However, Skinner and Wilde (1954) and Ishii and
Nogami (1964) disapproved of Lee's diagnosis because of thefact that their topotype specimens do possess an unusuallythin, but distinct, keriotheca both in the wall and septula as
in the case of Yabeina.
Although the validity of "Lepidolina" should have been
automatically null and void since that time, Ozawa (1970)
advocated its validity. He stated 'This difference in ecological habitat and chronological prosperity between both subfamilies (Neoschwagerininae and Lepidolininae) is noteworthy. This is one of the main reasons I separate Colania andLepidolina from the Neoschwagerininae.....". However, asa result of the present discovery, it is now evident that theso-called Lepidolina occurs together with Yabeina in a single
limestone sample regardless of inferred ecological factors.
Conclusively, the present discovery is a step toward asolution of the generic status problem of "Lepidolina".
Concerning its taxonomic position, we advocate, at least forthe present, the view of Yabe (1964a, b, 1965, 1966a, b) who
discussed this taxonomic problem in detail and concluded
that "Lepidolina" with the type species multiseptata should
be reserved as a subgenus of Yabeina Deprat. Apart fromits taxonomic problem, the present discovery points out thatthe species multiseptata is found in the Akasaka area fromthe limestone in association with Yabeina igoi, but not fromthe limestone typical of the Yabeina globosa subzone.
Figure 1. Index map showing locality of Yabeina (Lepidolina) multiseptata bearing limestone outcrop. (part of 1 :25,000 scaled topographic map of Ogaki City by GeographicalInstitute of Japan)

biostratigraphic position and biogeographic distribution ofmultiseptata, and its taxonomic position in the light of thepresent discovery.

It obviously shows that the species

multiseptata represents the lowest part of the Yabeina zone

in the Akasaka area, but not the same or higher level thanthe Yabeina globosa subzone as previously inferred by mostauthors. This discovery thus supports the view of Hanzawa
and Murata (1963) who placed the multiseptata zone below
the Yabeina globosa zone.
Contrary to the previous general notion of some fusuline
provincialists, the present discovery also clearly points outthat multiseptata can be found in association with somemembers of the Yabeina fauna. Even though further confirmation is probably necessary, it can be said that the
paleobiogeographic provinciality of these latest neoschwagerinids does not seem so prominent as previously
thought.
The species multiseptata was once assigned to the genus

Acknowledgments
The authors are deeply indebted to Yoshiaki Kimata of the
Gifu-ken Sekkai Kogy6 Kyod6 Kumiai, Ogaki City, Japan, for
his kind permission of trespassing on the limestone-quarrysites of the Akasaka area, and favorable arrangement forcarrying out field survey. Special thanks are also due toTakashi Sato of the Kinsho-zan Sekkaiseki K6zan who
accompanied and kindly assisted the first author in the field.
The authors would like to extend their sincere thanks to Dr.
Yoshihiro Mizuno, Department of Earth Sciences, Faculty of
Science, Chiba University, for his kind help in various ways
and constructive comments. The first author wishes toexpress his sincere thanks to Professor Toshiyuki Yamaguchi, Department of Earth Sciences, Faculty of Science, Chiba
University, for giving constructive comments, and also to the
Ministry of Education, Science and Culture of Japan forproviding a scholarship grant.

References cited
Akasaka Research Group, 1956: Geological studies of the
Akasaka limestone. Earth Sciences, no. 26, p.10-1B.

Figure 2. Yabeina (Lepidolina) multiseptata (Deprat) and associated neoschwagerinids. 1-4. Y. (L.) multiseptata, allfigures are x30 except 4 which is x40, slide nos. 3-1C-26, 3-1C-2, 3-1C-1 and 3-1C-25. 5. Yabeina igoi Morikawa andSuzuki, slide no.3-1C-B, x15. 6. Y. aft. globosa, slide no.3-1C-3, x 20.

"Neoschwagerina (Sumatrina) multiseptata" from Akasaka

549

550

Zaw Win and Sumio Sakagami(in Japanese with English abstract)
Deprat, J., 1912: Etude des Fusulinides de Chine et d'indochine et classification des calcaires a fusulines.
Memoires du Service Geologique de L'lndochine, vol. 1,
pt. 3, p.1-76, pis. 1-9.
Deprat, J., 1914: Etude des Fusulinides du Japon, de Chineet d'indochine. Etude comparative des Fusulinides d'
Akasaka (Japon) et des Fusulinides de Chine et d'indochine. Memoires du Service Geologique de L'lndochine, vol. 3, pt. 1, p.1-45, pis. 1-8.
Hanzawa, S. and Murata, M., 1963: The paleontological andstratigraphical consideration on the Neoschwagerininae
and Verbeekininae with the description of fusulinid
foraminifera from the Kitakami Massif, Japan. The
Science Reports of the Tohoku University, Ser. 2 (Geology), vol. 35, p.1-31, pis. 1-20.
Honjo, S., 1959: The Neoschwagerinids from the Akasaka
Limestone (Paleontological study of the Akasaka limestone, 1st Report). Journal of the Faculty of Science,
Hokkaido University, Ser.4 (Geology), vol. 10, no. 1, p.
111-161, pis. 1-11.
Ishii, K. and Nogami, Y., 1964: Contribution to the geology
and paleontology of Cambodia. Part 1. Permian
Fusulinids. Journal of Geoscience, Osaka City University, vol. 8, p.9-37, pis. 1-8.
Lee, J.S., 1933: Taxonomic criteria of Fusulinidae with notes
on some new Permian genera. Memoirs of the
National Research Institute, (Geology), no. 14, p.1-21,
pis. 1-5.
Morikawa, R. and Suzuki, Y., 1961: Fusulinids from the

Akasaka Limestone (part 2). The Science Reports of
the Saitama University, Ser. B, vol. 8, no. 1, p. 43-70, pis.
4-22.
Ozawa, T., 1970: Notes on the phylogeny and classificationof the superfamily Verbeekinoidea. Memoirs of theFaculty of Science, Kyushu University, Ser. D, vol. 20, p.
17-58, pis. 1-9.
Skinner, J.w. and Wilde, G.L., 1954: Fusulinid wall structure.
Journal of Paleontology, vol. 28, no. 4, p.445-451, pis.
45-52.
Yabe, H., 1964a: Lepidolina problems. Proceedings of theJapan Academy, vol. 40, no. 3, p. 213-219.
Yabe, H., 1964b: Problems on the genus Lepidolina (Part 1).
Fossils (Palaeontological Society of Japan), no. 8, p. 134139. (in Japanese)
Yabe, H., 1965: Problems on the genus Lepidolina (Part 2).
Fossils (Palaeontological Society of Japan), no. 9, p. 3655. (in Japanese)
Yabe, H., 1966a: Lepidolina problems; Supplementary
notes. Proceedings of the Japan Academy, vol. 42, no.
2, p. 141-145.
Yabe, H., 1966b: Problems on the genus Lepidolina (Supplement). Fossils (Palaeontological Society of Japan), no.
12, p.47-55. (in Japanese)
Yamagiwa, N. and Saka, Y., 1972: On the Lepidolina Zone
discovered from the Shima Peninsula, Southwest Japan.
Transactions and Proceedings of the PalaeontologicalSociety of Japan, New Series, no. 85, p.260-274, pis.
31-32.

551

PROCEEDINGS OF THE PALAEONTOLOGICALSOCIETY OF JAPAN

B:if;:iI~!Jo/J~~m 145 @]{1lJ~iI~, 6 J=I 29 B-----30 B f;:~7~:k~L'OO{iIU~ nt.: (~1JD1lf 147 i;) 0~ttm~B f,!ijLl1~5~$~~~...t1l (r-----$$$~®'t) ~~~lrfL!EM t iI~:tjl~7t··········· .ijg~{~:9c • ~~}llll9a~-Ij-)\ 1) >'i¥i$?;b 0 7tiB~~~m=*.1LLl1l1r$iI)~~'-'
t.:~YJJ~ Cyclocardia crebricostata (=&ffiO 1I::E~§£~·····················/J\31:mHlll9a~ • ~EB{j!-a~ • ~~}llll9a~~*li&fT· IJ\~

1*7Y7~$·iI~~~!Jo/J~~tT~~~~AJ;j§. Yu. Gladenkov· K. Barinov.................................... i!t~.A.: EBrR*4i-· flllifJ ~V >,M'y '7 .b.OO{~~jH~··················EBrR*4i- • flllifJ ~:Iill:i&!E1I::Ef;:i!l!;-:5 <~.JII*~$$iI~:Wtm.1H~* •~£I:i!lfl:*f1lij~~~f;::5t1!iT ~~m=*?ffi:l;&11 • ~f*EBII~i¥i$~t...t* t ~.l:t~····································~EBJ!iW~£I:i!lfl:*f1lij~~~f;::5t1!iT ~ $~®'t~f*EBlliI) ~ ~:Iill:i&!E

7 >''E / -1 r1l::EiI) ~ l:d.:*7 Y7 ~~Jv.b.*~-----=§,:*~iI
tiB~"""""""""""""""""""""""""""'" 7.i<ft ~ Z~£I:i!lfl:*f1lij~tiB~f;::5t1!iT ~ $~®'t~f*EBlliI) ~ ~~~1f~Jv.b.*~$WI*11~!EiI~!Jo/JtiB~t~.}lltiB*~~7!fj{............................................ ····~EB:m~ • E#{j!~WliI~1-t-lj- >' :f1I::E~:7HIi t -t- ~r..~~f;: -:::> \')l...................................................... ·········~JII 1}
iI~!Jo/J~~iI) ~ 17-t.:~Jv.b.*~~i¥i$~t...t* t m.5'!-~*...................................................... ·········EBrR*4i::1.-'7 V7*$~$~1-t1j!Jo/JtiB~, :lO J: lfBBU~1j!Jo/JtiB~

ftw· £I:i:if;:~* • EB$*-a~~**~~ • ~i1filitlE ••.1LX*

1I::Ern:tEM~······························~**~~· **ftW

fL!E Ammonia tochigiensis (Uchio) ~~I±l t -t-~~~················································ • .1LX*· £I:i:if;:~*~£I:i!lfl:\')b ~ rIJ~$~®til) ~~T ~+~Ej3mtm···1JDi1fi~{~lit~tiB~~tmP.jGr$$~®'t~1I J: ~ ~I±l '-'t.::k~1j!Jo/J1I::E

M····················································· ....... *$ ~:L1EfJi~~~tt~ t j(~:!Bf;: J: ~ f![fji~ff ~ JJ&T:L1Ef1l~~~iI~:tjl,~iE-~#!Ifl::Pt~~tiB~OO~~1I ~{1lH;: '-' l -...................................................... ······$JII~~MEt~T1ili!Jo/J~~7!fj{~· ~~1I::E:5t1!i~t~~~...................................................... ·········*ttJiIY3
MWlBBU~~*7 Y7~7 >''E-j--1 ~ 7;t t'~tx1*iJJ!Jo/J1I::E
t~~~iI~!Jo/JtiB~·····················fl}lllEW· f,!ij:fi1j ~:if;:nB~*~~.N~, f,!ij.N~, ~*~~~iJJ!Jo/JMt-t-..................................... EB1-tlEz:k~Wfftlb!Jo/J1I::E iI) ~ 17-t.: B:if;: t *7 y 7 ~ B~*~~!Jo/JtiB~~~I¥J:5t1!i""""~f;: -:::> \ , l l.................. ~i1fi~r& • *~fi1f:~ t !iUJi~:tjl···**~#!Ifl::Pt~~tiB~ ffi! 1I::EM~~Ilif~:5t1!i-~f;:WJm~~*1I::E
M~ f;: -:::> \, I I - ....................................... $ JII ~~ME

Palaeozoogeographic implication of fossil Angulyagrasp. (Gastropoda, Viviparidae) and Physunio sp.
(Bivalvia, Unionidae) in the molluscan faunal composition in'the Siwalik Group of Nepal................................................ Damayanti Gurung

jliif$ffi- • ftllifJ1}x
Vallupus T I) ~ 1) - (Y.:z. '7 *~:Iill:i&!EtiB~l25:) t *7 y7~$~1-tT~ ~~~ A·································flllifJ ~ODP B:if;:tm:J 7 f;: 17- ~*7y7~$·iI~~T~~~~A:m~~fitil~!Jo/J~

5?ffi~*~~f;::lO ft ~ mll9*~~WI ~~jlf'~1ffL!E Neo-~~ 1) >' ~ ················································:kilfi""&*~~ 7 t;1f: t B:if;:1U£I:i·································*tt~

globoquadrina JM~~iJJ ···············*7t51!ll!- • ~EB*~
r$E~* B!;J[rlJlli£'7 ~::1. 1) 11::E t -t-~iI~!Jo/J~I¥J~~~-.

7y7*~~:lO~~MWlB~e~fn~'7>'A7~-.b.

T.:z. :1' v 'Y =r V >' 7" t ::t 7 A ~ v -1 C >' 7" ..... '~rR:t±{11JD*~ P.jG f;: :lO ft ~ ~'@.:!B ~ ~~ ..................... B'r*4ix$. iI~~:Iill:i&!EiI)~17-t.:*7y7~iI~~~iJI............................................................... J\~

fIB

T1-AIb!Jo/JM~M~·······································im*;j§

Katsumi Takayasu • Keiji Matsuokan ~ i¥*'Ti!t~WI-----J!!~i!tMWI ~ J.:E

~1I::EM~~i¥i~t~11::·································iI~51rr················································:kJi!§.W~· B±:aE~*~:k~JBJEm Gigantoproductus ~iI~!Jo/JtiB~............................................................... ~Df(f.S'.*~.!Ifl:.tmE~:!B~:lO~~E~*:J/r>'~~II~...................................................... ·········.tt~Jt§~Jv .b.*~1\M-Ij- >' :f~-Ij- >,:J' t ;b >':1' 1) 7*~§£

552...................................................... ·········IT~¥$-Y -1 ~~~mv(' '/ -Y }v /' ~lj:ih~O) Ratburi EI.k-5iJ> t? ffE···························mip Dr.!!~ • 1EM iii· ~*%-fl~7';- if / ,/~ t ::1 ~ jf /~ O)1t:fill.O)lt~············Ij\iffi1!fj'.g:mLk~Nk~fin~~~U~/'~D.-~O)~.~~-1/'F*V7+"C-N~NciIMcto~t?ffE~6~I.$-=t i1~tJlo/]j:ih:@'$i¥J~~···I.!l!fMf~ • ~Jlrg~ . ~:j:j:~­-Y -1 ~~t*$tJ x-1 r1JJlI3<'~h:ffEm Lt.::~}vk*c7 /'''C-t-1
l' f;:-:J\r>c ···~JII~z· E.m ~. Nikorn Nakornsri~tI.rlJj:ih, *lirJtj:ih~iJ> t? 0)~T&M~}vk*c7 /'''C / -1 F';:*~~~···:j:iiiffiMf~ • !JXJif~T • I.!l!fMf~ • k -t A. I)-1 /' F.t, V7+"C-}v~0) Kolbano Complex iJ> t?ffE~ 6
MMB£m*c Tethys type' Non-tethys type ~~~............... ···mffiMf:!'J5 • k -t A. I) • !JXJi{~T • I.!l!fMf~

Paratirolites ............................................. 7kJ! I§z

AmrlJ~.~rlJm~t?ffEm~6=.;:~·~2~~~~~t~~~mj:ih~O)~ ·i11:W (~O) l)--=';:*O)-5f§:&rJ'~~~1tED.-·········J\~

B13' *l*mi!tT .!JX*}$~~~mj:ih~O) ~ • i11:W (~O) 2) -~}v k*c:m:i!t~~~1tED.-·· ............ ·~l*mi!tT • J\~ B13'!JX*}$

R:j:j:.D~$-=.;:*wmM.0)7/'''C-t-1I'1:.m~i¥J~~··········································E.m~. ~mllil~

g*~~m~E*MAl*~0)-=~rlJ*~0ffEmLk-=.;:~

1&M 0) 7 /' "C -t -1 l' f;: -:H> c······················· .!f:iZ!l!ff}tlt!
r'§J~~1ZcJIIj:ih~ffj(x:~*m*O),~~.DffEm/\~fflItJi'illO) 1:m:fif;:-:J\r>c···············rlJ~~u.]!;~· El*:¥M' $*~-T
ii¥Rj:ih~O)*~. ffElf:fnjJ~1tE···················· ·:f'~1mffi E2:~J!l!~m~lBJj:ih!l!fO)fD'*.D (I.$B£m* Maastrichtian)l."~ -:J iJ>? t.:: Enchodus gladiolus (~';- § X/'::1 F '/ A.

14) O)m 2 ~*···························:fr*lE~ • iffi~J!­~;f.&~O)~iri!tJllir • 7...flJ.ffE.:¥' /' /\ -Y"iJ ~~~JfHtEf;:

m.

-:J P c .. ···································· .~*~~ • rlJ J7g~%-= 1m • D -+(I. ff~ ~ :m:~) iJ> t? ffE mL t.:: Cosmopolitodus hastalis (Agassiz) -!f;'ff;: Cosmopolitodus hastalis o)*~f;:/mJ!l! L c - ........................... *$~1:
The earliest record of a choristodere from East Asia
(the middle Early Cretaceous Okurodani Formation,
Tetori Group, Shokawa, Gifu, Japan)........................... Makoto Manabe • Susan E. Evans
m:j:j:~MfrlJr1JO)~~.D~t:fr. (T$B£m*)ffEmO)~.

iJ ~!j~i'H;:-:Jv>c: .:y¥~··················:sy:rlJ

ltt· *¥$-

BrlJ~illO)~~.DT$B£m*~$~.ffEmo)iJ~.o)~• t 1:. J¥: .:y¥~ ...................................... ·:SY:rlJ 1tt*iFffir1JMfJ'z:. 0) ,~.1tE····························· .Ililj~~~
A new species of fossil Albatross (Aves: Procellariiformes: Diomedeidae) from the middle Miocene ofJapan and comments on the palaeontological recordof the Diomedeidae ........................... Paul G. Davism~~JfI3!ff~~*llIlMffE Imatotaria ~1tEf;: -::H>c················································g~m1t • Ij\;j;fB13=~1:~~@ml:tm~-$1:[QJ'Ii@ml:tm~-$1:iJ& v>~h-~Hi~0)~'1i0)~1tf;: ff -? jjJi~0)J1:t1t··· ............... :lfIi!J II*~~.~~.0)~tt~~~*~m~~~6~?-~-1~+W!lJW. ~fjIJ f;: - .......................................... Ei3ti§®:W
mJli~~L.O)*~i¥JmJa t ~ 0)J1:t1tJl:i¥J~~~O)~~................................................... :lfIi!

m*l' I) 7 A. • ~ 2 ~ *cmwr,,~Ji!li t ~tiffi -1 /' /j> ~ /' F 0) Lias •............................................................... :f'~1lilj ~:="2 -~-~ /' rq;:~ft 6~~~~~O)fJ1.tk t r'§J*~~mlD.···························~:j:j::m-=fl~ • f§ffi-aB13 • Ij\33:- A
t'rM~~ .:lfIi! flJ*' Sporli, K.B.
Grant-Mackie, J.A. • Hollis, c.J.
:=.. 2 - ~ - ~ /' F Whangaroa j:ih~ (Waipapa Terrane)0)+ 't' - l' .iJ> t? 0)~~~1tE................................ ·t'rM~~ • ;f§ffi-aB13 .:lfIi! flJ*
Ij\33: - A • Sporli, K.B .• ~:j:j::m-=fl~:=.. 2 -~-~ /' F, Kawhia j:ih:ilJj (Murihiku Terrane) 0)~T$ ~ 2 ~ *iJ> t? 0)~~~1tE···············f§ffi-aB13 .:lfIi! flJ*· Grant-Mackie, J.A.
Ij\33:- A • t'rM~~ • ~:j:j::m-=flB
Paleoceanography of Late Cretaceous "Indian Ocean"as reconstructed from planktonic foraminiferal
faunas" .................................. Maybellyn A. Zepeda
9li!1m.D~ ~ U!l!l1t5l&.DiJ> t? ffE L t.:: "t? -tt Ivtk coprolite"

f;:-:Jv>c .. ··································:lJotfi '$. !f-JII~~;:f /j -1f}v JJ" -1 14 =t?z:J"! 0)t ~. f;: -:J \r> c............................................... ·3fffi®:A • M~BJ3~

1JmE.

~:@i¥JmU~~~~~~~t?hk@~®1:=t?z:~.O)i11:

g t :ii1t······ ............................................. JlI~'*1:~Eli!J~O) HOM/HOX /j ~ A*~ :t if '/ /j AJ:lf~T................................................ -=p :kflB • Ji~-{iMTD .t, '/ l' f;: ~ ? cf*~ L t.::~1lWl$~ f;: ~ ft ~ fJ1.1:~Jfff'lifi:rL~f;:-:J\r>c .. ······················±.mlEift· ~ffi:k~
fJ1.1:EI.k.-t / /~ /'7 l' /' Gephyrocapsa oceanica O)~
1t~~~ ..... ............................. ·····~JI!f~T • :f'~lliljm~%J33:~-5~li@:j:ih~O) ~M~irt!tJ"! 1tEM········ ·~l*1TA~~ml2:!3*ffE~*=t?z:J"!, Lamprotula 0)J"!~:m~················································/j\;j;fM1t • T f1fffllt
w~~O)ni;,I.fjJ"!.J:liitD.·········1$:fr¥T • *ffi m553

m8 @litE ~ :=.?,- ~ 7 • 7ffl*"llIE~~~ji*JU~~~~.................................................. 'i!tffiSA: ~

~

554

Palaeontological Society of Japan (PSJ) Standing Committee Actions

During its meetings on April 20, and June 15, 1996, the PSJ Standing Committee enacted
the following changes to its membership, according to the new rule.
New members elected (April 20, 1966) ;Yasuko Fukuda,
Hiroki Hayashi,
Kayuri Nagaoka,
Takehisa Tsubamoto,
Tsutomu Sato,
Eriko Satou,
Mahito Watanabe,
Titima Charoentitirat.
New members elected (June 15, 1966) ;Takaomi Hamada,Kazuyoshi Moriya,
Ryosuke Nakamura,Kazuyuki Nozu,
Chinatsu Sanada,
Chiharu Shimizu,
Mikiko Ukita,
Tetsuya Tanaka,
Takumi Tsujino,
Shigetaka Yamaguchi, Kensuke Yasui,
David Chesanow,
Gurung Damayanti.
Paul G. Davis,
New Patron member (June 15, 1966) ;Kanagawa Prefectural Museum of Natural History.
Resigned members (April 20, 1966) ;Tomio Arakawa,
Eiichi Uchida,
Resigned members (June 15,1966) ;Yoshito Nakashima,
Hitoshi Nakagawa,Hiroko Suzuki.
Change to overseas member;
Tamaki Sato.

Ryuichi Uchimura.
Yoshihisa Nohmi,

,~-'---------- ___ "-.,-.~-_---""-"'-"'- 1'T*T~ .,--.. -.,-"--,'--.-..,------..-.----.-.-~t!

I © 1997 ifif~fi, 1997 if 1 Jj 30 B ~2 Jj 1 B f::, :&Am*~.f!l[~~~-e~110)T5E-eT ~~$l"j6c17-i!

tfi 12 Jj 5 B (&'¥r) friI6bW D-eT i;t jO 4 Jj fUf'JO) 181 i5f:: jO v' -C, :=. 0)~~$l"j6c17-~ B if· 10i
Jj 5 B t i;t -::> -C jO D ~ TiJ), 12 Jj 5 B iJ)lE l" v' B f;t-C'T jOb If l" -CUlE¥JI: l" ~ T o tI.
; © 1997 if-WU~fi, 1997 if 6 Jj f::, M.~mE!~~~tmtJ?;-c'1ffl110)T5E-C'T 0t©B*:tlli~~~%104if~Vllj*~ (~mlRd; 1997if10Jj 10 B-12 B) fi, B*r!l~tm~~f~iJ)o) :I~1JDl"t~J~l@J~Vllj*~ti;tD ~To B*r!l~~~~fi~Mr:pf::V:/J.Rs/'/.b.i'~1itl!v't~l,,~To V t:/J.Rs/'/1997 if 3 Jj -C'f::jO$l"j6c171,,'0I © 1998 ifif~ • *,~~&lfrq]ifO)% 147 @]-WU~0)1ffl11:tllii'~~ l" -C jO D ~ T o ;I.
I $j67t (Tm~JJii:m· V :/J.Rs/t/ .b.j£00i~JZS117t): T 169-50 **~~mlZ:E§lf!.frsEB 1-6-1
If!.frsEB*~q;JCw~~~:tlli~~:¥: 1JZJ!TsLJ]! (f'J*1*)i
I Fp~v,i?tb-\t7t 1JZJ!TsLJ]!: Tel. 03-5286-1516 Fax 03-3207-4950
II
E-mail hhirano@mn.waseda.ac.jp
ii
0

I

0

0

I
I

.b.j£OOi~fi

~

!

r~

!

I
I

!

I

~~

~ (f'J*1*~*): Tel. 03-3364-7104

i

Fax 03-3364-7104

1

E-mail manabe@kahaku.go.jptI~---------------------------------------------------~*~O)~fi~~T~.m~,~ftO)~.~~~,~$~M~~~.MM~i;t;lf~.M~

ftzp; o)~.iJ)~-C; h -CV' ~ To fI:(£O).M~ft fir§cO)Jm D -C'To

E

1 :/ j-:';t, V 7EtEl31*A~:t±oo*~~ if A 1*A~:t±~::i t 11 1'1'1 rtJ JL E! ~ ~ 1W tm i§
1'" 1 t' ::J :/ -tt }v l' :/ }- # E tEl3 Iffl ~ 1* A ~ :t±Si l' I~ /'.I. t Si-EiIl3IfflJE~~t±
W 00 E tEl3 1* A ~ :t±
2. ::L -SiY AI ~-1~:tJtLlf,§~

EtEl3~i~Iffl~1*A~t±~~~JLAtE!~O)1W~i§(7 1 '/ X;f JIOOi)

1996 ~ 9 FJ 25 B

EP

ijU

1996 ~ 9 FJ 30 B

9B

1T

ISSN

0031-0204~

fi ~iT ill 183 %
2,500 F9~

B
=r 113**"* ~ :>c"*~ *.if<iJ~ ¥ ~

B

$

*
m

~15

B *~~¥)}¥~¥~E

1W

t'lll

I2S:

~;) -16 - 9

0 ~ m~ / ~ - ~03-5814-5801. *c~

ED ,\llU~

T'984 fliJ#rIJ::6'UI25:1\T (l) §j§1I!J 8-45

'fft*"t±:llffiiJPijlj:f*;c\~t±'fft*" **~*t± 022-288-5555 *~ 03-3455-4415

i§Transactions and Proceedings of the PalaeontologicalSociety of Japan
September 30, 1996

New Series No. 183,,.
CONTENTS
TRANSACTIONS
1015. Michiko Saito: Early loop ontogeny of some Recent laqueid brachiopods . .... .. .... . .. 485
1016. Hisayoshi Kato : Miocene decapod crustacea from the Chichibu Basin, Central Japan
500
1017. Shuji Niko, Alain Pillevuit and Tamio Nishida : Early Late Permian (Wordian) non - ammonoid cephalopods from the Hamrat Duru Group, central Oman Mountains .. .. . . .. . . . . 522
1018. Fum io Kobayashi: Middle Triassic (Anisian) foraminifers from the Kaizawa Formation ,southern Kanto Mountains, Japan

528

SHORT NOTES
34.

Tatsuro Matsumoto: A little known species of Inoceramus (Bivalvia) from the Turonian(Cretaceous) of Hokkaido . ........... .... .. . . .... . . ... . . ... . .... .. . ................ 540

35.

Shuj i Niko, Alain Pillevuit and Tamio Nishida: Triassic aulacocerid (Mollusca: Cephalopoda) from the central Oman Mountains .. ..... . .. .. ............. ... .. .. . . ... . ...... 544

36.

Zaw Win and Sumio Sakagami : Preliminary note on the rediscovery of "Neoschwagerina(Sumatrina) multiseptata Deprat" from Akasaka, Japan .. .. ........... .. . ......... , ... . 547

PROCEEDINGS .... . ..... . ............................................ . . . .... 551