ISSN 0031-0204

Transactions and Proceedingsof the,Palaeontological Society of Japan
New Series

No.

170

Palaeontological Society of Japan
June 30, 1993

Co-Editors

Tsunemasa Saito and Kei Mori

Language Editor

Martin Janal (New York)

Editorial Board
Shiro Hasegawa (Hokkaido University), Kunihiro Ishizaki (Tohoku University), Tomoki Kase
(National Science Museum), Toshiaki Maruyama (Yamagata University), Kei Mori (Tohoku University), Kenshiro Ogasawara (University of Tsukuba), Tsunemasa Saito (Tohoku University), Y ok ichi Takayanagi (lshinomaki Senshu University), Kazushige Tanabe (University ofTokyo), Yukimitsu Tomida (National Science Museum), Kazuhiko Uemura (National Science Museum), Akira Yao(Osaka City University)

Officers for 1993-1994
President: Hisayoshi Igo
Honorary President: Teiichi Kobayashi
Councillors: Kiyotaka Chinzei, Takashi Hamada, Yoshikazu Hasegawa, Itaru Hayami,
Hiromichi Hirano, Hisayoshi Igo, Noriyuki Ikeya, Junji Itoigawa, Tomoki
Kase, Makoto Kato, Tatsuaki Kimura, Itaru Koizumi, Kei Mori, Hiroshi Noda,
Ikuwo Obata, Kenshiro Ogasawara, Tomowo Ozawa, Tsunemasa Saito, Yokichi
Takayanagi, Kazushige Tanabe, Akira Yao
Members of Standing Committee: Kenshiro Ogasawara (General Affairs), Tomoki Kase
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Papers), Tamiko Ohana (Friends of Fossils)
Auditor: Hisaharu Igo
The fossil on the cover is Isocrinus (Chladocrinus) hanaii Oji, an Early Cretaceous(Aptian) crinoid, which was described from the Hiraiga Formation exposed at Haipe,
Tanohata-mura, Shimo-Hei County, Iwate Prefecture, Northeast Japan. (University
Museum of the University of Tokyo coil. cat. no. ME6950, paratype specimen, length
about II cm)

All communication relating to this journal should be addressed to the

PALAEONTOLOGICAL SOCIETY OF JAPAN. c/o Business Center for Academic Societies,
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Trans. Proc. Palaeont. Soc. Japan, N.S., No. 170, pp. 133-158, 10 Figs., June 30, 1993

953.

MIDDLE AND UPPER CARBONIFEROUS FUSULINACEANSFROM THE TAISHAKU LIMESTONEGROUP, SOUTHWEST JAPAN*
KATSUMI UENO
Institute of Geoscience, University of Tsukuba, Ibaraki, 305
andYOSHIHIRO MIZUNO
Division of Environmental Science, Graduate School of Scienceand Technology, Chiba University, Chiba, 263

Abstract. Middle and Upper Carboniferous fusulinacean biostratigraphy of the
Taishaku Limestone Group in the Unata area situated in the southern part of the Taishaku
Plateau, Hiroshima Prefecture, is examined and five fusulinacean zones; the Fusulinella
bingoensis, Fusulina quasicylindrica, and Obsoletes cf. obsoletus-Protriticites ovatus Zones in
the uppermost part of the Eimyoji Formation, and the Triticites (Rauserites) stuckenbergiJigulites dagmarae and Occidentoschwagerina chatcalica Zones in the lowermost part of the
Uyamano Formation in ascending order, are established. Based upon the faunal similarityof fusulinaceans between the Taishaku Limestone Group and the Carboniferous standard
and reference sections of the Russian Platform and other regions, the Fusulinella bingoensis
and Fusulina quasicylindrica Zones are correlated with the Myachkovsky Horizon of the late
Moscovian, the Obsoletes cf. obsoletus-Protriticites ovatus Zone with the lower Kasimovian,and the Triticites (Rauserites) slllckenbergi-Jigulites dagmarae and Occidentosch wagerina
chatcalica Zones with the Gzhelian in the Russian Carboniferous standard stratigraphic
scheme. This fact reveals that at least the lowermost part of the Uyamano Formation in the
Unata area, which has long been regarded as Permian, is in the Upper Carboniferous. In
this paper, all the identified fusulinaceans including one new species, Fusulinella bingoensis,
sp. nov., are described. The present report provides important evidence not only on the
Middle and Upper Carboniferous fusulinacean biostratigraphy of the Taishaku LimestoneGroup but also on the biostratigraphic significance of the Fusulina fauna in the Akiyoshi"Terrane."
Key words. Akiyoshi "Terrane," Fusulina Zone, fusulinacean biostratigraphy, Middle
and Upper Carboniferous, Taishaku Limestone Group.

preted to have originated in an oceanic
seamount during Late Paleozoic time. Afterthe pioneer works by Hanzawa (1941) andFujimoto (1944), many students paleontologically and biostratigraphically studied foraminifers, corals, calcareous algae, mollusks,
and bryozoans of the Taishaku LimestoneGroup. According to Okimura (1987), theTaishaku Limestone Group is biostratigra-

Introduction

The Taishaku Limestone Group, located in
the northeastern part of Hiroshima Prefecture,is one of the large greenstone-limestonebodies in the Akiyoshi "Terrane" in the Inner
Zone of southwest Japan and has been inter'Received May 25, 1992; accepted December 7, 1992
133

Katsumi Veno and Yoshihiro Mizuno

134

phically subdivided into 12 foraminiferal
zones. Paleontological and stratigraphicalknowledge of the Fusulina (or Beedeina) andTriticites Zones (upper Middle and Upper
Carboniferous) in the Taishaku LimestoneGroup, however, remains poor, especiallyknowledge of their faunal characteristics andstratigraphic relationship.
Recently, we investigated the Taishaku
Limestone Group in the Unata area, which isone of the Fusulina localities presented by
Hase el al. (1974), for the purpose of
elucidati ng the biostratigraphic significanceand faunal characteristics of the Fusulina
Zone as well as the stratigraphic relationshi p
between the Eimyoji and Uyamano Formations. We identified five fusulinacean faunas
from a late Moscovian to Gzhelian age in theuppermost part of the Eimyoji and the lower-

132°E

most part of the Uyamano Formations.
In the present paper, we discuss thefusulinacean biostratigraphy of the uppermost part of the Eimyoji and the lowermost
part of the Uyamano Formations in the
Unata area and the fusulinacean faunal succession near the Middle and Upper Carboniferous boundary in the Taishaku LimestoneGroup. Moreover, all the identified
fusulinaceans including one new species,
Fusulinella bingoensis, sp. nov., are described.
This report incl udes the first systematic
description of fusulinacean species comprising the Fusulina fauna in the Akiyoshi "Terrane" and provides many important data
concerning the biostratigraphic significanceof the Fusulina fauna and the stratigraphic
relationship between the Beedeina andFusulina Zones in the Akiyoshi "Terrane" in

134°E

36°N

Taishaku

•

o

o

lkm

I

133°14'E

Figure 1.

Index map of the Unata area in the Taishaku Plateau.

953.

Carboniferous fusulinaceans from Taishaku

the Inner Zone of southwest Japan.

koyama (1966, 1970), and Sad a et al. (1984).
Among them, Sada and Yokoyama (1970)
reported the fusu1inacean fauna of theFusulinella Zone in the Taishaku LimestoneGroup and described the following three
species; Fusulinella taishakuensis Sada, F.
biconica (Hayasaka), and Eoschubertella sp.
They correlated the Fusulinella fauna of the
Taishaku Limestone Group with those of the
Huang10ng (Huanglung) Limestone in South
China and the Upper Atokan in North Amer-

Review of foraminiferal biostratigraphyof the Taishaku Limestone Group
Biostratigraphic study of the Taishaku
Limestone Group by foraminifers arose fromthe pioneer works by Hanzawa (1941) andFujimoto (1944), and was furthered by Yokoyama (1959), Okimura (1966), Sad a (1967,
1969, 1972, 1973, 1975, 1977), Sada and Y 0-,,,"
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Figure 2. Map showing the localities of collected samples wit~. t.he indicati~ns of containe?
fusulinacean faunas. I: Occidentoschwagerina chatcalica fauna, 2: Tntlcltes (Rausentes) stuckenberglJigulites dagmarae fauna, 3: Obsoletes cf. obsoletus-Protriticit~s ovalUs fauna, 4 :. :usulina q.uasi?lindrica
fauna, 5: Fusulinella bingoensis fauna, 6: fauna uncertam, 7: rhyolo-dacltlc volcaniclastic rocks(Cretaceous).

136

Katsumi Veno and Yoshihiro Mizuno

ica.
Sada (1973) summarized the fusulinacean
biostratigraphy of the Permian division of the
Taishaku Limestone Group and establishedthe Triticites sp. A Subzone in the Pseudosch wagerina Zone as the lowermost biostratigraphic unit, which was correlated with thelower Wolfcampian in North America. He
determined that the Triticites sp. A Subzone(Pseudoschwagerina Zone) unconformably
overlies the Fusulinella Zone in the Taishaku
Limestone Group.
Later, Sad a (1975) distinguished four
fusulinacean zones in the Carboniferous division of the Taishaku Limestone Group, namely the Eostaffella kanmerai Zone in the
Dangyokei Formation and the Millerella
bigemmicula, Profusulinella toriyamai, andFusu lin ella taishakuensis Zones In the
Eimyoji Formation.
Hase et al. (1974) comprehensively investigated the stratigraphy of the Taishaku Limestone Group and recognized two distinctive
sedimentary facies, the central and marginalones. They explained that the central facies
represents shallow marine sediments on reef
proper and the marginal facies exemplifies
rather deep water sediments on fore-reef slope
to near-reef basin, which are derived mainly
from the former. They divided the central
facies of the Taishaku Limestone Group into
the following three formations in ascendingorder, namely the Dangyokei, Eimyoji, andUyamano Formations, and correlated theformer two with the Lower and Middle
Carboniferous and the last one with theLower to Middle Permian, respectively. In
that study, they noted that in the Unata area
the upper Eimyoji Formation (Fusulina
Zone) of late Middle Carboniferous age isunconformably overlain by the lower Uyamano Formation (Pseudoschwagerina Zone)of earliest Permian age and concluded that
the Upper Carboniferous Triticites Zone isentirely lacking even in the whole area of the
Taishaku Limestone Group.
Recently, Okimura (1987) reviewed thelitho- and biostratigraphy of the Taishaku
Limestone Group and distinguished theEimyoji Formation into the Millerella bigemmicula. Pseudostaffella antiqua, Profusulinella toriyamai, Fusulinella taishakuensis. andFusulina Zones in ascending order. He concluded, however, that paleontological knowledge of the Fusulina Zone in the Taishaku
Limestone Group still remains poor becauseof its restricted, narrow distribution.
Geologic setting and fusuIinacean
biostra tigrapby
The surveyed area, about 0.5 km south of
Unata on the left bank of the Simotaishakukyo Gorge, is located about 8 km southwestof Tojo (Figure 1). In this area, it is known
that the lower Uyamano Formation(Pseudosch wagerina Zone) and the upper
Eimyoji Formation (Fusulinella-Fusulina
Zone) of the central (main) facies of the
Taishaku Limestone Group are exposed andthe Fusulina Zone which is not well understood biostratigraphically in the Akiyoshi"Terrane" in the Inner Zone of southwest
Japan is distributed restrictedly (Hase et al.,1974). Rhyolo-dacitic volcaniclastic rocksof Cretaceous age (Hase et al., 1974) widely
cover the Taishaku Limestone Group in thisarea.
As shown in Figure 2, a total of 34 samples
were collected systematically and theirfusulinacean faunas and microfacies were
examined. The Taishaku Limestone Group
exposed in the Unata area is almost entirelycomposed of a massive and pure bioclastic
limestone and reaches about 40 m in thickness(Figure 3). It is currently divided into the
Eimyoji and Uyamano Formations. Sixteen
species belonging to I I genera offusulinaceans were extracted. Based upon
the stratigraphic distribution offusulinaceans, the Eimyoji Formation is further subdivided biostratigraphically into the
Fusulinella bingoensis, Fusulina quasicylindrica, and Obsoletes cf. obsoletus-Protriticites

953.

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t::::rI9t::s=£~ 1715

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f§2E 13o125~51looCarboniferous fusulinaceans from Taishaku

Fq

g:2S=:l23! :::::~.

J :'

Fb

.. ...... presumed
unconformity

Figure 3. Columnar section of the uppermost
part of the Eimyoji and the lowermost part of the
Uyamano Formations in the Unata area. Oc:
OccidenlOschlVagerina chatcalica Zone, T-J:
Triticites (R auserites) stuckenbergi-Jigulites dagmarae Zone, O-P: Obsoletes cf. obsolelus-Prolriliciles
ovalUS Zone, Fq: Fusulina quasicylindrica Zone,
Fb: Fusulinella bingoensis Zone.

ovatus Zones, and the Uyamano Formation
into the Triticites (Rauserites) stuckenbergiJigulites dagmarae and Occidentoschwagerina chatcalica Zones in ascending order (Figure 4).
The Fusulinella bingoensis Zone is thelowest stratigraphic unit in the surveyed area
and is at least about 10 m in thickness.
Algal-fusulinacean packstone is dominant
and algal-fusulinacean grainstone is common.
The fusulinacean fauna contains Fusulinella
bingoensis, sp. nov., Pseudofusulinella (Kanmeraia) ex gr. pulchra (Rauser-Chernoussova
and Beljaev), and Pseudofuslilinella (Kanmeraia) sp.
The Fllsulina qllasicylindrica Zone, about

18 m

thick,

conformably

137

overlies

theFuslilinella bingoensis Zone and yields
Fuslilina quasicylindrica Lee, Fllsulinella bingoensis, sp. nov., Pseudofllslllinella (K anmeraia) ex gr. pulchra (Rauser-Chernoussova
and Beljaev), Schubertella sp., and Nankinella sp. Algal-fusulinacean grainstone andalgal-fusulinacean packstone are predominant.
The Obsoletes cf. obsoletus-Protriticites
ovatus Zone conformably overlies the
Fusulina quasicylindrica Zone and is about
4 m thick. Algal grainstone and algalfusulinacean grainstone are dominant. The
diagnostic fusulinaceans in this zone are
Obsoletes cf. obsoletus (Schellwien) andProtriticites ovatus Putrja.
The Triticites (Rauserites) stllckenbergiJigulites dagmarae Zone is about 5 m inthickness and ooid-algal grainstone andalgal-crinoidal grainstone are predominant .
A fusulinacean faunal break exists between
the Obsoletes cf. obsoletus-Protriticites ovatus
and the Triticites (Rauserites) stuckenbergiJigulites dagmarae Zones. The unconformable stratigraphic relationship is, therefore,
assumed between the present zone and thesubjacent one, although no evidence of unconformity is observed in the field. The
following fusulinaceans are diagnostic:
Triticites (T.) sch wageriniformis Ra userChernoussova, T. (Rauserites) stuckenbergi
Rauser-Chernoussova, T. (R.) lucidus
Rauser-Chernoussova, Jigulites dagmarae(Rozovskaya), and Jigulites sp.
The Occidentoschwagerina chatcalica
Zone is at least 5 m in thickness and algalcrinoidal grainstone is dominant.
Fusulinacean fauna includes Occidentoschwagerina
chatcalica
Bensh,
Rugosofusulina sp. A, and Rugosofusulina?
sp. B. This zone may conformably overlies
the Triticites (Rauserites) stuckenbergiJigulites dagmarae Zone.

Katsumi Veno and Yoshihiro Mizuno

138

Uyama noEimyojiF.
Formation

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."

t:r

.Q

I

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I

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0

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N

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::::I
CD

Species

Fusulinella bingoensis, sp. nov.
Pseudofusulinella (Kanmeraia) ex gr. pulchra

P. (K.) sp.
Fusulina quasicylindrica
Nankinella sp.
Schubertella sp.
Obsoletes cf. obsoletus
Protriticites ovatus
Triticites (T.) schwageriniformis
T. (Rauserites) stuckenbergi
T. (R.) lucidus
Jigulites dagmaraeJ.

sp.

Occidentoschwagerina chatcalica
Rugosofusulina sp. A

R.? sp. B
Figure 4. Stratigraphic distribution of fusulinaceans in the uppermost part of the Eimyoji and thelowermost part of the Uyamano Formations in the Unata area. Abbreviations of zone names: see legendof Figure 3.

Correlation
Most of the fusulinaceans identified in the
Unata area are also rather common in or
closely related to other species occurring in
the Carboniferous standard or reference sections of the Moscow Syneclise, South Urals,
Donets Basin, Central Asia, and South
China. This makes it possible to discuss theprecise correlation of the fusulinacean zones
established in this study with those of the
Middle and Upper Carboniferous standard
stratigraphic scheme in the Russianstratotypes represented by Ivanova et al.

(1979) and Rauser-Chernoussova et al.
(1979). Correlation of fusulinacean zones inthis study with the Russian Carboniferous
standard stratigraphic scheme is shown in
Table I.
The index species of the Fusulinella bingoensis Zone is morphologically related to F.
vozhgalensis molokovensis RauserChernoussova and F. pseudobocki ovoides
Rauser-Chernoussova, both of which were
described from the lower Myachkovsky Horizon of the Moscovian in the Russian Platform(Rauser-Chernoussova et al., 1951). This
species is also closely similar to Fusulinella

953.

Carboniferous fusulinaceans from Taishaku

139

Table 1. Correlation of fusulinacean zones established in this study with those in the Russian
Carboniferous standard stratigraphic scheme.

:i
eX
t.LI

"-

Soko1iegorsky" Sch wagerina" l'ulgaris"Schwagerina" fusiformis..J

Noginsky

Daixina sokensis~

Pavlo-Posadsky

Jigulites jigulensis

Amerevsky

Triticites (R.) stuckenbergi

Rusavkinsky

Triticites (R.) rossicus

Yauzsky

Triticites (T.) arcticus

Dorogomilovsky

Triticites (T.) acullls~

Khamovnichesky

Montiparus montiparusu.i

Krevyakinsky

Protriticites pseudomontiparusObsoletes obsoletus

Obsoletes cf. obsoletusProtriticites Ol'atus

Fusulina cylindrica
Fusulinella bocki
Fusulinella eopulchra

Fusulina quasicylindrica

Myachkovsky------------------------------------.-------------

Podolsky

Fusulinella colaniae
Fusulinella vozhgalensis
Fusulina kamensis

<r::

Zone

.. _----------------.--------- ---------------------

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d)
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This study

Zone

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Rauser-Chernoussova et al., 1979
Horizon

11 u.i'"c0

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<r::

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0

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Occidentosch wagerina chatcalica---_._--------------------------------- --._-------

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chuanshanensis Lee and Chen from the
Huanglong Limestone of South China where
Fusulinella pseudobocki Lee and Chen, andFusulina quasicylindrica Lee are associated(Lee et al., 1930). Fusulina quasicylindrica
Lee from the Taishaku Limestone Group is
closely related to F. cylindrica (Fischer deWaldheim) which is considered to be an
important element among the fusulinacean
faunas in the upper Myachkovsky Horizon
and its equivalents (Rauser-Chernoussova etal., 1951; Sheng, 1958; Ivanova et al.,1979). For these reasons, the Fusulinella
bingoensis and Fusulina quasicylindrica
Zones are correlated with the Myachkovsky
Horizon of the Moscovian.
The succeeding zone contains Obsoletes cf.

Triticites (R.) stuckenbergiJigulites dagmarae

Fusulinella bingoensis

obsoletus (Schellwien) and Protriticites
ovatus Putrja. The former is a well known
species in the lower Kasimovian and its
equivalents in the Tethyan province (RauserChernoussova et al., 1979; Aisenverg et al.,
1979; Watanabe, 1991 and others). The
latter was originally described from the C~(=q (N)) and lower C~( =q (0)) Suites ofthe eastern Donbass (Putrja, 1948). It wasrecorded also from the uppermost Moscovian
and the lowermost Kasimovian of the Moscow Basin (lvanova et al., 1979). In general,
the Protriticites-Obsoletes fauna is considered
to be a good indicator of an early
Kasimovian age (Rauser-Chernoussova etal., 1979). Consequently, the Obsoletes cf.
obsoletus-Protriticites ovatus Zone seems to be140

Katsumi Veno and Yoshihiro Mizuno

correlated with the lower Kasimovian
Protriticites pseudomontiparus-Obsoletes obsoletus Zone in the Moscow Syneclise, Donets
Basin, and Central Asia (RauserChernoussova et al., 1979; Aisenverg et al.,
1979; Bensh, 1972).
The Triticites (Rauserites) stuckenbergiJigulites dagmarae Zone contains species
fairly identical to those recorded in the Carboniferous standard and reference sections in
Russia and other regions. One of the zone
species, Triticites (Rauserites) stuckenbergi
Rauser-Chernoussova, is a good index of thelower Gzhelian (Rauser-Chernoussova, 1958
and others). The other zone species,
Jigulites dagmarae (Rozovskaya), was originally described from the middle and upper
Gzhelian (Rozovskaya, 1950). The genus
Jigulites is, at present, considered to haveflourished in the lower and middle Gzhelian(Popov et al., 1985). Triticites (Rauserites)
lucidus Rauser-Chernoussova was recorded
from the lower Gzhelian Triticites stuckenbergi Zone (Rauser-Chernoussova, 1958;
Rozovskaya, 1958). Triticites (T.) sch wageriniformis is a rather long-ranging species
which occurs from the upper Kasimovian tothe lower Asselian (Rauser-Chernoussova etal., 1979). According to the abovementioned evidence, this zone is evidently
referable to the lower and middle Gzhelian.
The index species of the Occidentoschwagerina chatcalica Zone was originallydescribed by Bensh (1962) from the lowermost Permian of North Fergana, and also
recorded from the Asselian Occidentoschwagerina alpin a and "Schwagerina"moelleri-Pseudofusulina' fecunda Zones ofSouth Fergana (Bensh, 1972). Recently, thisspecies was reported from the Daixina postsokensis Zone which is equivalent to the lower
half of the Daixina bosbytauensis-Daixina
robusta Zone of late Gzhelian age(Davydov, 1990). Although the genus
Occidentoschwagerina is common in the basal
Permian, it is also an important element in
the upper Gzhelian (Popov et al., 1985).

The genus Rugosofusulina is common in theuppermost Carboniferous and lowermost
Permian (Popov et al., 1985). From theevidence mentioned above as well as thestratigraphic relationship with the subjacent
Triticites (R a use rites ) stuckenbergi-Jigulites
dagmarae Zone, and the fact that thefusulinacean fauna of the present zone does
not contain any Sphaerosch wagerina or
Pseudoschwagerina species which is considered to characterize the basal Permian(Watanabe, 1991), it may be correlated withthe upper Gzhelian.
It becomes obvious that the uppermost partofthe Eimyoji Formation in the Unata area iscorrelated with the uppermost Moscovian tolower Kasimovian, and the lowermost part of
the Uyamano Formation with the Gzhelian.
This means that at least the lowermost part of
the Uyamano Formation in this area, which
has long been considered to be Permian, is of
Late Carboniferous age. Moreover, a stratigraphic hiatus which is almost equivalent to
the middle and upper Kasimovian exists
between the Eimyoji and Uyamano Formations in this area.
The upper Moscovian in the Akiyoshi"Terrane" in the Inner Zone of southwest
Japan has long been represented as theBeedeina Zone, which is characterized by theoccurrence of the genera Beedeina, Fusulinella, and Pseudofusulinella, such as Beedeina
akiyoshiensis Zone by Ota (1977) and Ueno
(1989), and Beedeina akiyoshiensis, Fusulinella pseudobocki, and Pseudofusulinella hidensis Zones by Ozawa and Kobayashi (l990) in
the Akiyoshi Limestone Group and theFusulinella pulchra Zone by Watanabe (l973)
in the Omi Limestone Group. The equivalent zone is not known or less understood in
the Atetsu and Taishaku Limestone Groups.
In the present paper, we explained that theFusulina fauna in the Taishaku LimestoneGroup is surely referable to that in the
Moscovian Myachkovsky Horizon, probably
its upper part. On the contrary, theBeedeina fauna (Beedeina akiyoshiensis

953.

Carboniferous fusulina ceans from Taishaku

141Zone) in the Akiyoshi Limestone Group , forexample, is suggested to be referable to that in
the upper Podolsky Horizon (Ueno , 1989;
Ozawa and Kobayashi, 1990). It is concluded that the Fusulina fauna is younger than the
Beedeina fauna (Beedeina akiyoshiensis
Zone) in the Akiyoshi "Terrane," although
the stratigraphic relationship between the
Beedeina and Fusulina Zones is notconfirmed in the Taishaku Limestone Group.
This suggests that the Fusulina Zone can be
redefined as a fusulinacean genus zone in theuppermost Moscovian or the upper hal f of theBeedeina Zone.

Systematic description
All specimens identified in this paper aredeposited in the paleontological collectionsof the Institute of Geoscience, University ofTsukuba (JGUT).
Order Foraminiferida Eichwald, 1830
Suborder Fusulinina Wedekind , 1937
Superfamily Fusulinacea vonMoller, 1878
Family Schubertellidae
Skinner, 1931
Subfamily Schubertellinae
Skinner, 1931
Genus Schubertella Staff
and Wedekind , 1910

Schubertella sp.
Figures 5- 3- 8

Remarks.- The present species is closely
similar to Schubertella aff. kingi Dunbar andSkinner described by Ueno (1991) from thelower Kasimovian Quasifusulinoides
toriyamai Zone of the Akiyoshi Limesto ne
Group.
Figured specimens.-Axial sections ;IGUT-KU0466 , IGUT-KU0468, IGUTKU0469, JGUT-KU0470 , IGUT-KU0471.
Sagittal section; IGUT-KU0467 . All spec imens from Loc. SF 15.

Figure S. 1,2 : Nankinel/a sp. , axial sections,
IGUT-KU0464, IGUT-KU0465 . 3- 8. Schubemllasp., 3,5- 8: axial section s, IGUT-KU0466, IGUTKU0468 , IGUT-KU0469, IGUT-KU0470, IGUTK U047 1, 4 : sag illa l section , IGUT-KU0467.
All x 40.

Family Fusulinidae von Moller, 1878
Subfamily Fusulinellinae Staff
and Wedekind , 1910
Genu s Fusulinella vo n Moller, 1877

Fusulinella bingoensis Ueno a nd Mizuno ,sp. nov.
Figures 6- 1- 6

Diagnosis. - Large Fusulinella having athickly biconvex shell with broadly rounded
periphery, massive and highly asymmetricalchomata, and well defined tunnel path.
Coiling planispiral throughout.
Description. - Shell large for gen us andthickly biconvex with broadly rounded
periphery and bluntly pointed polar ends.
Mature specimens of 6 Yz to 7 volutions 4.45
to 5.60 mm in length and 2.25 to 2.60 mm inwidth , giving form ratios of 1.98 to 2.21.
A verage form ratio 2.10 for 4 specimens.
The holotype of 7 volutions 4.98 mm in

142

Katsumi Veno and Yoshihiro Mizuno

Figure 6. 1- 6. Fusulinel/o bingoensis Ueno a nd Mizuno, sp. nov. , 3: axial section of the hol o ty pe,
IG UT-K U0474, 1,6 : ta ngential secti o ns o f para types, IG UT-K U0472 , IGUT-K U0477 , 2: ax ia l secti o n ofparatype, IG UT-KU0473 , 4: sag ittal secti o n of para type, IGUT-KU0475 , 5: ax ial sectio n of immature
spec imen o f para type, IG UT-K U0476 , x iS. 7 : Pseudofusulin el/a (Kal1l17eraia) sp., ax ia l section , IGUTK U0478 , x 20.

length and 2. 25 in widt h with a form ratio of
2.21.
Shell uniformly expanded and plani spirall ycoiled throughout growth. Radius vectors of
the first to seventh volution of the ho lotype
0.10, 0.15,0.22 , 0.36, 0.56, 0.82, and 1. 14 mm ,and form ratios 1.20, 1.93, 2.30, 2.43 , 2.33 ,2.40, and 2.19, respectively.
Proloculus sma ll and spherical. Its o utside di ameter ranges from 0.120 to 0.150 mm ,averaging O. I 37 mm for 5 specimens.
Spirotheca rather thick and compo sed of atectum , thin diaphanotheca , and thick upperand lower tectoria. Thickness of spirothecaof the first to seve nth vo l uti on of the holotype
0.025 , 0.030,0.035 , 0 .050 , 0 .060 , 0.070, a nd
0.050 mm.
Septa weakly fluted on ly in extreme polar

region s. Chomata broad and massive, highly asymmetrical, and well developed in al lvo luti o ns except for the last half vo luti on .
They extend to polar region s while decreasing
in height. Tunnel side of chomata very
steep, but their outside slopes very gentle.
Tunnel path almo st straight. Tunnel anglesof the third to sixth vo luti on of the hol o type40, 45 , 38 a nd 45 degrees.
Remarks. - Fusulinella bingoensis, sp. nov.
is one of the largest species in the gen us. It is
clo se ly related with Fusulinella vozhgalensis
molokovensis and F. pseudobocki ovoides,
both described by Rau ser-Chernou ssova (inRauser-Chernou ssova et al. , 195 1) from thelower My achk ovsky Hori zo n of the Russian
Platform. The former, however, differs fromthe latter in having a larger shel l and more953.

Carboniferous fusulinaceans from Taishaku

massive chomata.
The present new species is similar to
Fusulinella chuanshanensis described by Lee
and Chen (in Lee et al., 1930) from the
Huanglong Limestone of South China. The
latter species, however, has a more compactly
coiled shell than does ours.
Fusulinella bingoensis, sp. nov. somewhat
resembles Fusulinella biconica (Hayasaka),
the well known species in the Moscovian
Fusulinella Zone of the Akiyoshi "Terrane,"
but can be easily distinguished from the latterin having a larger shell and form ratio.
Etymology.- The specific name is derived
from Bingo, the ancient name for the countryaround the eastern half of Hiroshima Prefecture, where the Taishaku Plateau is located.
Figured specimens.-Axial section of theholotype; IGUT-KU0474 from Loc. SF2.
Axial section of paratype; IGUT-KU0473
from Loc. SF2. Axial section of immature
specimen of paratype; IGUT-KU0476 from
Loc. SF2. Sagittal section of paratype;
IGUT-KU0475 from Loc. SF26. Tangential
sections of paratypes; IGUT-KU0472 from
Loc. SF2, IGUT-KU0477 from Loc. SFI6.
Genus Pseudofusulinella Thompson, 1951
Subgenus Kanmeraia Ozawa, 1967

Pseudofusulinella (Kanmeraia)
ex gr. pulchra(Rauser-Chernoussova andBeljaev, 1940)
Figures 7-1-30
Fusulinella pufchra Rauser-Chernoussova and Beljaev
in Rauser-Chernoussova el af., 1940, p.23-27,

73, pI. 5, figs. 1-6.

Description.-Shell medium for genus andelongate fusiform with bluntly pointed polarends and straight to slightly concave lateralslopes. Mature specimens having 6 to 7 Yz
volutions, 3.00 to 4.43 mm in length and 1.10
to 1.80 mm in width. Form ratio ranges
from 2.25 to 3.16, averaging 2.57 for 22 specimens.

143

Shell rather compactly coiled throughout
growth. Axis of coiling straight. Radius
vectors of the first to seventh volution of
typical oriented specimen (Figure 7-8a) 0.10,
O. I 5, 0.20, 0.29, 0.40, 0.53, and 0.72 mm, andform ratios 1.50, 1.80, 1.86, 1.90, 2.63, 2.82,
and 2.65, respectively.
Proloculus small and spherical. Its outside diameter ranges from 0.075 to 0.130 mm,
averaging 0.102 mm for 38 specimens.
Spirotheca thin and composed of a tectum,
diaphanotheca, and thin upper and lower
tectoria. Lower tectorium unobserved inouter one or two volutions of some specimens. Thickness of spirotheca of the first to
seventh volution of specimen mentioned
above 0.025, 0.025, 0.030, 0.030, 0.030, 0.035,
and 0.030 mm.
Septa almost plane or very weakly fluted
only in extreme polar regions. Septal countsof the first to sixth vol ution of one ill ustrated
sagittal section (Figure 7-13) 10,13,15,16,
18, and 21. Chomata highly asymmetrical,
small and high to broad and massive, andwell developed in all volutions except for thelast half volution of some specimens. Tunnel side of chomata very steep, overhanging insome cases, but their outside slopes moderate
to gentle. Tunnel path narrow and almost
straight. Tunnel angles of the second tosixth volution of above-mentioned axial section 19,20, 19,25, and 31 degrees. No axial
fillings present.
Remarks.- The following species are considered to comprise the species group of
pulchra; Fusulinella usvae Dutkevich, 1934;
Fusulinella pulchra Rauser-Chernoussova
and Beljaev, 1940; Wedekindellina prolifica
Kanmera, 1954; Wedekindellina? hidensis
Kanuma, 1958; Pseudofusulinella tempelensis Ross, 1965; Pseudofusulinella praeantiqua Wilde, in Nassichuk and Wilde, 1977.
Pseudofusulinella (Kanmeraia) ex gr. pulchra (Rauser-Chernoussova and Beljaev) canbe distinguished from "P. (K.) ex gr. itoi
(Ozawa) et subpulchra Putrja" proposed by
Ginkel (1987) in having a larger and more

Katsumi Veno and Yoshihiro Mizuno

144

elongate fusiform shell and larger form ratio.
Moreover, the former occupies a higher stratigraphic position than the latter.
Broad morphological variations in the
shape of chomata and thickness of spirotheca
are observed in the Taishaku specimens.
Specimens with broad, massive and highly
asymmetrical chomata and relatively thickspiro theca (e.g. Figure 7-29) are generally
found in micritic limestone, whereas specimens having high and small chomata andrelatively thin spirotheca (e.g. Figure 7-8a)
commonly occur in limestone with sparitic
matrix.
Figured specimens.-Axial sections;
IGUT-KUOS06, IGUT-KUOS07 from Loc.
SFI0, IGUT-KU0479, IGUT-KU0480,
IGUT-KU0482, IGUT-KU0484, IGUTKU048S, IGUT-KU0486, IGUT-KU0488,
IGUT-KU0489, IGUT-KU0490, IGUTKU0493, IGUT-KU0498, IGUT-KUOSOO,
IGUT-KUOS02, IGUT-KUOS04 from Loc.
SFlS, IGUT-KUOSOl, IGUT-KUOS03,
IGUT-KUOSOS from Loc. SF20. Sagittal
sections; IGUT-KU0481, IGUT-KU0483,
IGUT-KU0491, IGUT-KU0492, IGUTKU0496, IGUT-KU0497 from Loc. SFlS,
IGUT-KUOS08 from Loc. SFI9. Tangential
sections; IGUT-KU0494, IGUT-KU049S,
IGUT-KU0499 from Loc. SFlS.

Pseudofusulinella (K anmeraia) sp.
Figure 6-7

Remarks.- This unidentified species can beeasily distinguished from Pseudofusulinella(Kanmeraia) ex gr. pulchra (RauserChernoussova and Beljaev) in having a muchsmaller shell.
Figured specimen.-Axial section; IGUT-

KU0478 from Loc. SF2.
Gen us Protriticites Putrj a, 1948

Protriticites ovatus Putrja, 1948
Figures 8-11-13

Prolriliciles ovaWs Putrja, 1948, p. 93-94, pI. 1, fig. 9 ;Rauser-Chernoussova el al., 1951, p. 318-319, pI.
57, fig. 3; Mikhaylova, 1974, p. 46, pI. 1, figs. 1112,14.
I
Prolriliciles subsch wagerinoides Rozovskaya, 1950, p.
9-10, pI. 1, figs. 5-7.

Description.-Shell small and fusiform withrounded periphery. Mature specimens having
6 Yz to 7 volutions, 3.40 to 4.07 mm in lengthand I.S7 to 2.10 mm in width, giving form
ratios of 1.94 to 2.17. Inner few volutions
rather tightly coiled. Shell planispirally
coiled throughout growth. Proloculus smalland spherical, being 0.08S to 0.110 mm inoutside diameter. Spirotheca thin and consists of a tectum, poorly defined diaphanotheca, and upper and lower tectoria in inner
volutions, but of a tectum and rather thicklower perforated layer in outer ones. Septa
weakly fluted only in extreme polar regions.
Chomata massive and highly asymmetrical,
and well developed in all volutions. Tunnel
path somewhat irregular.
Remarks.-Protriticites ovatlls was originally described by Putrja (1948) from the q(=q (N)) and lower q (=q (0)) Suites ofeastern Donbass and can be distinguishedfrom P. globulus Putrja, the type species of thegenus, in having a smaller shell. The Taishaku specimens quite agree with the original
one by Putrja (1948).
Protriticites sllbsch wagerinoides describedby Rozovskaya (19S0) from the uppermost~
Figure 7. 1-30. Pseudofusulinella (Kanmeraia) ex gr. pulchra (Rauser-Chernoussova and 8eljaev), 1,
2,4, 6-8a, 10-12, 15,20,22-29: axial sections, IGUT-KU0479, IGUT-KU0480, IGUT-KU0482, IGUTKU0484, IGUT-KU0485, IGUT-KU0486, IGUT-KU0488, IGUT-KU0489, IGUT-KU0490, IGUT-KU0493,
IGUT-KU0498, IGUT-KU0500, IGUT-KU050I, IGUT-KU0502, IGUT-KU0503, IGUT-KU0504, IGUTKU0505, IGUT-KU0506, IGUT-KU0507, 3,5,9,13,14,18,19,30: sagittal sections, IGUT-KU0481, IGUTKU0483, IGUT-KU0487, IGUT-KU0491, IGUT-KU0492, IGUT-KU0496, IGUT-KU0497, IGUT-KU0508,
16,17,21: tangential sections, IGUT-KU0494, IGUT-KU0495, IGUT-KU0499, X 15, 8b: enlarged part of8a, x50.

953.

Carbonifel'OLIS fusulinaceans JI'OI11
r
Taishaku

14 5

"
I

8a

.

.

"

\,',

.. . .

;

. ".

13

146

Katsumi Veno and Yoshihiro Mizuno

part of the Middle Ca rbonifero us (q = Myachkovsky Horizon) and the lowermost part of
the Upper Carboniferous (q - a=C 3 A t ) of theRussian Platform h as massive chomata andrather tightly coiled inner volutions, andalmost the same dimension as Protriticites
ovatus Putrja. The former seems to be identical with the latter.
Figured specimens.-Axia l sections;
IGUT-KUOS 20, IG UT-KUOS 2 1. Sag ittal
sect ion ; fGUT-KUOS I 9. All specimensfrom Loc. SF21.
Genus Obsoletes Kireeva, 19S0

Obsoletes cf. obsoletus(Schellwien , 1908)
Figures 8- 1- 9, 10 (?)

Compare. Fusulina obsoleta Sche ll wien, 1908, p. 167 - 168, pI. 19,
fi gs. 5- 7.
NeoJusu line//a obsoleta (Schellwien). Lee, 1927, p.
18- 19, p I. 2, fig. 19.
Prolriliciles obsolelUs (Schellwien). Putrja , 1948, p.
94, pI. I, fig. 7; Ro zovs kaya , 1950, p. 10-11 , pI. I,
figs. 1- 4 ; Sheng, 1966, p. 37, pI. 5, fig. I (sa me as
pI. 10, fig. 12 of Sheng, 1958, p. 36- 37, 95 - 96) .
Obsoleles obsolelus (Schellwien). R a u se rChernoussova and Fursenko, 1959, pI. 7, fi g. 8

Figure 8. 1- 9,1O(?). Obsoletes cf. obsolelUs (Schellwien), 1,3,4, Sa, 6, 7,10 : axia l secti ons,
IGUT-KU0509, IG UT-KU05 11 , IGUT-K U05 12, IGUT-KU0513, IGUT-KU05 14, IG UT-KU05 15, IGUTK U0518 , 2,8,9: sagitta l section s, IGUT-KU05 10, IGUT-K U0516, IGUT-KU0517, X 15 , 5b: enlarged
pan of Sa , x 40. 11 - 13. PrOlriliciles ovalus Putrj a, 12a, 13 : axial section s, IG UT-KU0520, IGUTKU0521 , 11 : sag itta l sect ion , IGUT-KU05 19, X 15 , 12b : en la rged part of 12a, x 40.

953.

Carboniferous fusulinaceans from Taishaku(same as pI. 1, fig. 2 of Rozovskaya, 1950, p. lO11); Chen, 1963, pI. 1, figs. 2-3, pI. 2, fig. 3 ;Pasini, 1965, pI. 7, fig. 1 (same as pI. 19, fig. 7 ofSchellwien, 1908, p. 167-(68); Niikawa, 1978, p.
562-563, pI. 12, figs. 1-2; Fang, 1988, pI. 1, figs.
5-6; Ozawa and Kobayashi, 1990, pI. 3, figs. 1618; Ozawa et al., 1991, figs. 3-1-2 (same as pI.
3, figs. 16, 18 of Ozawa and Kobayashi, (990);
Watanabe, 1991, figs. 20-1-23, 22-1-3.
Obsoletes obsoletes (Schellwien). Grozdilova, 1966,
p. 263-264, pI. 2, figs. 1-2; Rozovskaya, 1975, pI.
12, figs. 5-6 (5: same as pI. 19, fig. 7 of SchelIwien, 1908, p. 167-168,6: same as pI. I, fig. 2 ofRozovskaya, 1950, p. 10-(1); Grozdilova et al.,1975, p. 52-53, pI. 11, fig. 2.
Obsoletes obsoleta (Schellwien). Loeblich andTappan, 1988, pI. 267, figs. 10-12 (same as pI. 19,
figs. 5-7 of Schellwien, 1908, p. 167-(68).
Obsoletes cf. obsoletus (Schellwien). Veno, 1991, p.
818, figs. 4-9-13.
Protriticites afr. obsoletus (Schellwien). Sheng, 1958,
p. 36-37, 95-96, pI. 10, fig. 12.
? Obsoletes obsoletes (Schellwien). Mikhaylova,
1974, p.47, pI. 1, fig. 13.

Remarks.- The Taishaku specimens possess a slightly larger shell than those previously referred to Obsoletes obsoletus (Schellwien)
including the origin,al ones. The referral to
Obsoletes obsoletus (Schellwien) is therefore
tentative.
The present species is probably conspecificwith Obsoletes cf. obsoletus (Schellwien) described by Ueno (1991) from the uppermost
part of the Protriticites sp. Zone of the
Akiyoshi Limestone Group, southwest Japan.
Figured specimens.-Axial sections;
IGUT-KUOS09, IGUT-KUOSII, IGUTKUOSI2, IGUT-KUOSI3, IGUT-KUOSI4,
IGUT-KUOSIS, IGUT-KUOSI8. Sagittal
sections; IGUT-KUOSIO, IGUT-KUOSI6,
IGUT-KUOSI7. All specimens from Loc.
SF21.
Subfamily Fusulininae von Moller, 1878
Genus Fusulina Fischer de Waldheim,
1829 emend. Ishii, 19S8

Fusulina quasicylindrica Lee, 1927
Figures 9-1-23

147

Fuslilina (Girtyina) qllasicylindrica Lee, 1927, p.3539, pI. 4, figs. 10-19; Lee and Chen in Lee et al.,1930, p. 133-134, pI. 12, figs. 8-14, pI. 13, figs. 14.

Girtyina qllasicylindrica var. brevis Lee, 1927, p.3940, pI. 5, figs. 1-2.
FlIslilina qllasicylindrica (Lee). Rauser-Chernoussoya in Rauser-Chernoussova et al., 1951, p.
305-306, pI. 52, figs. 2-4; Sheng, 1958, p. 48,
107-108, pI. 15, figs. 15-18, pI. 16, figs. 1-4;
Sheng, 1966, p. 46, pI. 6, fig. 6 (same as pI. 4, fig.
15 of Lee, 1927, p. 35-39); Sheng et al., 1976, pI.
3, figs. 17-21 ; Lin et al., 1977, p.29-30, pI. 6,
fig. 2; Wang et al., 1982, p.47, pI. 8, fig. 14;
Xie, 1982, p. 15, pI. 5, fig. 12; Zhang and liang,
1984, pI. 1, figs. 22, 26; Xia and Zhang, 1985, p.
61-62, pI. 7, fig. 1 ; Wang, 1987, pI. 1, fig. 28;
Zhang et al., 1987, p.257, pI. 4, fig. 5; Lin etal., 1991, p. 101, pI. 17, figs. 18, 19,21.
FlIslilina qllasicylindrica var. compacta Sheng, 1958,
p.48-49, 108, pI. 16, figs. 5-7; Sheng, 1966, p. 47,
pI. 6, fig. 10 (same as pI. 16, fig. 5 of Sheng, 1958,
p.48-49, 108); Wu et al., 1974, pI. 5, fig. 23;
Zhang and Wang, 1974, p.260, pI. 131, fig. 12;
Xia and Zhang, 1985, p. 62, pI. 6, fig. 8.
FlIslilina qllasicylindrica var. megaspherica Sheng,
1958, p. 49, 108, pI. 16, figs. 8-10; Sun et al.,1983, p. 15, pI. 3, fig. 14; Zhang et al., 1987, p.
257, pI. 4, figs. 6-7.
FlIslilina qllasicylindrica var. brevis (Lee). Sheng,
1966, p. 46-47, pI. 6, fig. 11 (same as pI. 5, fig. I of
Lee, 1927, p.39-40)
FlIslilina megaspherica Sheng. Li n et al., 1991, p.
100, pI. 17, figs. 14-16.
? FlIslilina quasicylindrica (Lee). Kanuma, 1958, p.
33, pI. 3, figs. 24-26.

Description.-Shell large for genus andelongate cylindrical with bluntly pointed
axial regions. Mature specimens having 6 to
8, rarely 8 Yz volutions, S.20 to 7.9S mm inlength and 1.70 to 2.80 mm in width. Formratio varies from 2.87 to 3.98, averaging 3.24
for II specimens.
Shell rather tightly coiled throughout
growth. Axis of coiling straight. Radius
vectors of the first to eighth volution of typical axial section (Figure 9-6a) 0.11,0.16,0.22,
0.28,0.38,0.50,0.66, and 0.88 mm, and form
ratios 1.09, 1.63,2.09,3.34,3.67,4.02,4.01,
and 3.93, respectively.
Proloculus commonly spherical, but rarely
somewhat irregular. Outside diameter of148

Katsumi Veno and Yoshihiro Mizuno

proloculus ranges from 0.160 to 0.265 mm,
averaging 0.212 mm for 27 specimens.
Spirotheca thin and composed of a tectum,
diaphanotheca, and poorly defined upper andlower tectoria. Thickness of spirotheca of
the second to eighth volution of abovementioned specimen 0.020, 0.025, 0.025, 0.030,
0.025,0.045, and 0.050 mm.
Septa thin, numerous, and intensely andregularly fluted throughout shell length
except for tunnel path. Septal counts of thefirst to eighth volution of one sagittal section(Figure 9-20) 12,20,24,27,35,40,43, and49 ?, respectively. Chomata small and commonly developed in only inner few volutions,but rarely observed in middle ones of somespecimens. Tunnel path narrow andstraight. Tunnel angles of the second toseventh volution of above-mentioned axial
section 13, 16, 17, 20, 20, and 26 degrees.
Weak axial fillings developed in most specimens.
Remarks.- The Taishaku specimens arealmost identical with the original ones of
Fusulina quasicylindrica Lee, except for having a slightly larger shell, more vol utions andslightly smaller form ratio.
Sheng (1958) proposed two new varieties,
compacta and megaspherica, for Fusulina
quasicylindrica Lee. The former is characterized by a compactly coiled shell and small
proloculus, and the latter by a larger
proloculus, somewhat loosely coiled shell,
and absence of axial fillings. These morphological characters, however, are seemingly
considered to demonstrate merely an
intraspecific variation.·
Fusulina quasicylindrica Lee can be distinguished from F. cylindrica (Fischer de Waldheim), the type species of the genus, in having
a larger shell and more volutions.

Figured specimens.-Axial sections (including slightly oblique sections); IGUTKU0543 from Loc. SF9, IGUT-KU0522,
IGUT-KU0524, IGUT-KU0525, IGUTKU0526, IGUT-KU0527, IGUT-KU0529,
IGUT-KU0530, IGUT-KU0531, IGUTKU0532, IGUT-KU0535, IGUT-KU0536,
IGUT-KU0537, IGUT-KU0538, IGUTKU0539, IGUT-KU0540, IGUT-KU0544
from Loc. SFI5. Sagittal sections; IGUTKU0523, IGUT-KU0528, IGUT-KU0533,
IGUT-KU0534, IGUT-KU054I, IGUTKU0542 from Loc. SFI5.
Family Schwagerinidae Dunbar andHenbest, 1930
Subfamily Schwagerininae Dunbar andHenbest, 1930
Gen us Triticites Girty, 1904
Subgenus Triticites Girty, 1904

Triticites (Triticites)
sch wageriniformis
Rauser-Chernoussova, 1938
Figures 10-13-15

Triticites sch wageriniformis Rauser-Chernoussova,
1938, p. 107-108, 155, pI. 3, figs. 1-3; Grozdilova
and Lebedeva, 1960, p. 177-178, pI. 32, fig. 4 ;Chen and Wang, 1983, p. 59-60, pI. 6, fig. 14, pI.
8, figs. 12-14, pI. 9, fig. I ; Zhou et al., 1987, pI.
I, figs. 9-10; Lin et al., 1991, p. 106-107, pI. 18,
figs. 16-18.
Triticites ( Triticites) sch wageriniformis sch wageriniformis Rauser-Chernoussova. Rozovskaya,
1950, p. 23, pI. 5, figs. 1-5; Rozovskaya, 1958, p.
88, pI. 3, fig. II
Triticites schwageriniformis parallelos Scherbovich,
1969, p.9-1O, pI. 2, figs. 6-10; Isakova andNazarov, 1986, p. 26-27, pI. 2, fig. I.
Triticites sch wageriniformis parallelos forma
compacta Scherbovich, 1969, p. 10, pI. 2, fig. 11.
Triticites sch wageriniformis sch wageriniformis
Rauser-Chernoussova. Mikhaylova, 1974, p.

~
Figure 9. 1-23. Fusulina quasicylindrica Lee, 1,3-5, 6a, 8-11,14-19,22,23: axial sections (including slightly oblique axial sections), IGUT-KU0522, IGUT-KU0524, IGUT-KU0525, IGUT-KU0526, IGUTKU0527, IGUT-KU0529, IGUT-KU0530, IGUT-KU0531, IGUT-KU0532, IGUT-KU0535, IGUT-KU0536,
IGUT-KU0537, IGUT-KU0538, IGUT-KU0539, IGUT-KU0540, IGUT-KU0543, IGUT-KU0544, 2,7,12,
13,20,21: sagittal sections, IGUT-KU0523, IGUT-KU0528, IGUT-KU0533, IGUT-KU0534, IGUTKU0541, IGUT-KU0542, X 10, 6b: enlarged part of 6a, X 50.

953.

Carboniferous fusulinaceans from Taishaku

149

~
-

3

23

150

Katsumi Veno and Yoshihiro Mizuno
54-55, pI. 3, figs. 7-8; Grozdilova el al., 1975, p.
57, pI. 13, fig. I.

Remarks.-Several subspecies have been
proposed for Triticites (T.) schwageriniformis
Rauser-Chernoussova. Among them,
Triticites (T.) schwageriniformis parallelos,
originally described by Scherbovich (1969)
from the upper Kasimovian and Gzhelian of
the Precaspian Syneclise, seems to beconspecific with Triticites (T.) sch wageriniformis (s.s.), judging from the original illustration.
Figured specimens.-Axial sections;
IGUT-KU0556 from Loc. SF32, IGUTKU0557 from Loc. SFI2. Sagittal section;
IGUT-KU0558 from Loc. SFI2.
Subgenus Rauserites Rozovskaya, 1948

Triticites (R a use rites ) stuckenbergi
Rauser-Chernoussova, 1938
Figures 10-1-5

Triliciles slUckenbergi Rauser-Chernoussova, 1938, p.
110-112, 155-156, pI. 3, figs. 4, 9; Grozdi1ova
and Lebedeva, 1960, p. 173-174, pI. 29, fig. 4 ;Mikhaylova, 1974, p. 59, pI. 4, fig. 6; Grozdi1ova
el al., 1975, p. 57, pI. 12, fig. 9 (same as pI. 29, fig.
4 of Grozdi1ova and Lebedeva, 1960, p. 173174); Rozovskaya, 1975, pI. 13, fig. 2 (same as pI.
3, fig. 4 of Rauser-Chernoussova, 1938. p. 110112, 155-156); Chen and Wang, 1983, p.66-67,
pI. 10, fig. 16, pI. 20, fig. 13; Xia and Zhang,
1985, p. 82, pI. 8, fig. 13; Loeblich and Tappan,
1988, pI. 284, fig. 10 (same as pI. 3, fig.4 ofRauser-Chernoussova, 1938, p.110-112, 155156); Fang, 1988, pI. 1, fig. 24; Xia in Ding elal., 1991, pI. 4, fig. 13; Watanabe, 1991, figs. 421-24,27,9-1-6.
Triticites (R auserites) stuckenbergi Ra userChernoussova. Rozovskaya, 1950, p.33-34, pI.
6, figs. 10-13; Rozovskaya, 1958, p. 94, pI. 6, fig.
4; Chuvashov et al., 1986, p. 77, pI. II, fig. 7 ;Ozawa and Kobayashi, 1990, pI. 4, fig. 12;
Ozawa el al., 1991, figs. 3-12-13.

Description.-Shell medium for genus andfusiform with bluntly pointed polar ends.
Mature shell of 6 to 7 Yz volution 4.50 to 5.15
mm in length and 2.13 to 2.55 mm in width'
giving form ratios of 2.05 to 2.14.

Early volutions somewhat tightly coiled ascompared with outer ones. Axis of coilingstraight throughout. Radius vectors of thefirst to seventh vol ution of oriented specimen
illustrated on Figure 10-1 ; 0.10,0.17,0.26,
0041, 0.62, 0.87, and 1.16 mm, and form ratios
lAO, 1.28, 1.66, 1.74, 1.94, 2.02, and 2.03,
respectively.
Proloculus small and spherical. Its outside diameter ranges from 0.120 to 0.190 mm,
averaging 0.145 mm for 4 specimens.
Spirotheca thin and composed of a tectumand keriotheca. Thickness of spirotheca of
the first to seventh volution of abovementioned specimen 0.015, 0.030, 0.030, 0.050,
0.070,0.075, and 0.045 mm.
Septa moderately fluted in polar regions,but intensity decreases toward central part ofshell. Chomata present in all vol utions
except for the last one in some specimens.
Tunnel angles of the first to sixth volution ofabove-mentioned specimen 29, 20, 20, 22, 28,
and 38 degrees.
Remarks.- Triticites (Rauserites) stuckenbergi was originally described by RauserChernoussova (1938) from the Upper Carboniferous of the Samara Bend in the Russian
Platform. Recently, Watanabe (1991) illustrated many specimens of the present species
from the Schwagerina? satoi Zone of the
Atetsu Limestone Group, southwest Japan.
The Taishaku specimens are almost identicalwith the Atetsu ones.
Figured specimens.-Axial sections;
IGUT-KU0545, IGUT-KU0546 from Loc.
SF31, IGUT-KU0547 from Loc. SF32.
Sagittal section; IGUT-KU0549 from Loc.
SF32. Tangential section; IGUT-KU0548
from Loc. SFI2.

Triticites (R allSe(ites) lucidus
Rauser-Chernoussova, 1958
Figures 10-6-8

Triticites llicidus Rauser-Chernoussova, 1958, p. 133134, pI. I, fig. 4.
Triticites (Rauseriles) lucidlls Rauser-Chcrnoussova.

953.

Carboniferous fusulinaceans from Taishaku

Figure 10. 1- 5. Triliciles (Rauseriles) stuckenbergi Ra user·C herno ussova, 1- 3: ax ial sect io ns,
IGUT-KU0545 , IGUT-KU0546, IGUT-KU0547 , 4 : ta nge nti a l sectio n, IGU T-KU0548, 5 : sagittal secti o n, IG UT-K U0549. 6- 8. Triliciles (Rauserites) lucidus Rauser-Chernoussova, 6,7: ax ia l sectio ns,
IGUT-KU0550, IGUT-KU0551 , 8 : sag ittal secti o n, IGUT-KU0552. 9- 11. Jiguliles dagmarae (Rozovskaya) , 9, 10 : ax ial sectio ns, IG UT-K U0553 , IGUT-KU0554, 11: sagittal section , IGUT-KU0555. 12:
Jigulites sp. , ax ial section , IGUT-K U0559. 13- 15. Trilicites (Triliciles) sch wageriniformis Rau serC herno ussova, 13,14: ax ial section s, IG UT-KU0556, IG UT-K U0557 , 15: sagitta l sectio n, IGUTKU055 8. 16,17. Occidentoschwagerina chatcalica Bensh, 16: ax ia l section , IGUT-KU0560, 17 : sag ittal
secti o n, IGUT-KU056 1. 18- 20. Rugosofusulina sp. A , 18: sagi tt al section , IGUT-KU0562, 19,20 : axia l
sectio ns, IGU T -KU05 63, IGUT-KU0564. 21 - 23. Rugosofusulina? sp. B, 21: sag ittal section , IGUTKU0565 , 22,23: ax ia l sections, lGUT-KU 0566, IGUT-KU0567. All X 10.

15 1

152

Katsumi Ueno and Yoshihiro Mizuno
Rozovskaya, 1958, p. 100, pI. 9, figs. 6-7.

Description.-Shell small and fusiform withbluntly pointed axial regions and gently
rounded periphery. Mature shell of 6 to 7
volutions 3.13 to 4.28 mm in length and 1.75
to 2.15 mm in width, giving a form ratio of
1. 79 to 2.11.
Axis of coiling straight throughout. Innerfew volutions rather compactly coiled, but
outer ones uniformly expanded. Radius
vectors of the first to seventh volution of one
axial section (Figure 10-6) 0.09,0.15,0.23,
0.38,0.57,0.81, and 1.08 mm, and form ratiosof 1.33, 1.47, 1.63, 1.56, 1.88, 1.94, and 1.96,
respectively.
Pro10culus small and spherical, being 0.085
to 0.130 mm in outside diameter.
Spirotheca thin and composed of a tectumand keriotheca. Thickness of spiro theca of
the first to seventh vol uti on of abovementioned specimen 0.015, 0.025, 0.040, 0.050,
0.060, 0.075, and 0.055 mm.
Septa moderately and regularly fluted
throughout length of shell, except for its
central part. Chomata small and developedin all vo1utions. Tunnel path narrow andalmost straight. Tunnel angles of the second
to seventh volution of specimen mentioned
above 22,21,23,23,28, and 31 degrees.
Remarks.- The Taishaku specimens areslightly larger in shell size than RauserChernoussova's original ones from the
Triticites stuckenbergi Zone of an early
Gzhelian age.
Figured specimens.-Axia1 sections;
IGUT-KU0550, IGUT-KU0551. Sagittal
section; IGUT-KU0552. All specimensfrom Loc. SF31.
Genus Jigulites Rozovskaya, 1948

Jigulites dagmarae (Rozovskaya, 1950)

Jigulites ? ex gr. dagmarae (Rozovskaya). Davydov,
1990, pI. 1, fig. 5.
Schwagerina dagmarae (Rozovskaya). Watanabe,
1991, figs. 9-12-18.

Description.-Shell medium for genus andinflated fusiform with broadly expanded
periphery and almost straight lateral sl~pes.
Mature specimens having 5 to 6 volutlOns,
5.20 to 5.53 mm in length and 2.78 to 2.88 mm
in width with form ratios of 1.81 to 1.99.
The first vo1ution tightly coiled. Shell
expands rather rapidly beyond the second
volution. Axis of coiling straight throughout growth. Radius vectors of the first to
fifth volution of one illustrated axial section(Figure 10-10) 0.18,0.30,0.51,0.81, and 1.18mm, and form ratios 1.05, 2.03, 1.96, 1.71, and1.75, respectively.
Proloculus almost spherical and measuresfrom 0.190 to 0.170 mm in outside diameter.
Spiro theca rather thick and composed of atectum and keriotheca. Thickness of spirotheca of the first to fifth volution of abovementioned specimen 0.030, 0.045, 0.060, 0.100,
and 0.080 mm.
Septa intensely and regularly fluted
throughout shell length, forming narrow andhigh septal loops. Chomata massive anddeveloped from the first to penultimate volution. Tunnel path narrow and somewhat
irregular.
Remarks.-Jigulites dagmarae was described by Rozovskaya (1950) from the q-d
and Pseudofusulina Horizons (middle andupper Gzhelian) of the Russian Platform.
Recently, Watanabe (1991) reported thisspecies from the Schwagerina? satoi Zoneof the Omi Limestone Group, central Japan.
Figured specimens.-Axial sections;
IGUT-KU0553 from Loc. SF33, IGUTKU0554 from Loc. SF32. Sagittal section;
IGUT-KU0555 from Loc. SF32.

Figures 10-9-11

Jigulites sp.

Triticites (Jigulites) dagmarae Rozovskaya, 1950, p.
39-40, pI. 8, figs. 6-7; Rozovskaya, 1958, p. 103,
pI. 10, fig. 6.

Figure 10-12

Remarks.- The

present

unidentified

953.

Carboniferous fusulinaceans from Taishaku

153

species can be distinguished from Jiguliles
dagmarae (Rozovskaya) in having a more
inflated and tightly coiled shell, more massive
chomata and smaller proloculus.
Figured specimen.-Axial section; IGUTKU0559 from Loc. SFI2.

larger form ratio and less expanded outer
volutions.
Figured specimens.-Axial section;
IGUT-KU0560. Sagittal section; IGUTKU056I. Both specimens from Loc. SF34.

Gen us Occiden tosch wagerinaMiklukho-Maklay, 1959

Subfamily Rugosofusulininae Davydov,
1980
Genus Rligosofuslilina RauserChernoussova, 1937

Occidentoschwagerina chatcalica
Bensh, 1962

Rugosofllsulina sp. A

Figures 10-16-17

Figures 10-18-20

Occidentoschwagerina fllslllinoides chatcalica Bensh,
1962, p. 220- 221, pI. 14, figs. 1- 2.
Occidentoschwagerina chatcalica Bensh. Bensh, 1972,
p. 115, pI. 26, figs. 1-2; Davydov, 1990, pI. 3,
figs. 3-4.

Remarks.- The present unidentified
species somewhat resembles Rugosofusulina
alpina (Schellwien), especially R. alpina var.
communis described and illustrated by Schellwien (1898). The former, however, differsfrom the latter in having more massive
chomata and more compactly coiled Inner
volutions.
This species can be distinguished from
Rugosofusulina prisca [(Ehrenberg) emend.
Moller], the type species of the genus, inhaving a larger shell and more expandedouter volutions.
Figured specimens.-Axial sections;
IGUT-KU0563, IGUT-KU0564. Sagittal
section; IGUT-KU0562. All specimensfrom Loc. SF34.

Descriptive remarks.-Shell small for genus
and fusiform with bluntly pointed polar ends.
Mature specimens of 5 to 6 volutions 5.60 to6.30 mm in length and 2.40 to 2.90 mm inwidth, giving form ratios of 2.33 to 2.63.
Inner few volutions tightly coiled. Outerones expand rather rapidly and become loose.
Proloculus small, being 0.050 to 0.070 mm inoutside diameter. Spirotheca thin and composed of a tectum and keriotheca, and showing some rugosity. Septa intensely andrather irregularly fluted throughout shelllength. Chomata observed only in Inner
volutions.
Occidentoschwagerina chatcalica was originally described by Bensh (1962) from North
Fergana. Later, it was recorded from theAsselian Occidentoschwagerina alpina and"Sch wagerina" moelleri-Pseudofusulina
fecunda Zones of South Fergana by Bensh(1972). Recently, this species was reported
from the uppermost Gzhelian Daixina postsokensis Zone of the Predonets Depression by
Davydov (1990).
Occidentoschwagerina tianshanensis described by Chang (1963) from Xinjiang is theclosest to the present species. However, theformer differs from the latter in having a

Rugosofllslllina ? sp. B
Figures 10-21-23

Remarks.- This species can be easily distinguished from Rligosofllslllina sp. A in
having a smaller and more elongate shell, andlarger form ratio. It is slightly similar tosome species of the genus Schagonella. In
this study, the present species is, therefore,
tentatively referred to the genus RugoSOflisulina.
Figuredspecimens.-Axial sections;
IGUT-KU0566, IGUT-KU0567. Sagittal
section; IGUT-KU0565. All specimensfrom Loc. SF34.

154

Katsumi Veno and Yoshihiro Mizuno
Family Staffellidae Miklukho-Maklay,
1949
Genus Nankinella Lee, 1934

Nankinella sp.
Figures 5-1-2

Remarks.- The present species somewhat
resembles Nankinella yokoyamai describedby Sada (1972) from the Profusulinella Zoneof the Taishaku Limestone Group. The
exact specific identification of this species,
however, is postponed owing to insuffi.ciencyof material.
Figured specimens.-Axial sections;
IGUT-KU0464, IGUT-KU0465 from Loc.
SF15.
Acknowledgments
We would like to express our cordial
thanks to Prof. Hisayoshi Igo of the University of Tsukuba for his critical reading of themanuscript. Thanks are also extended toProf. Sumio Sakagami of Chiba University
for his continuous guidance and encouragement, and to Mr. Masao Tanabe of Nitto
Funka K.K. for his kind convenience during
our field survey. The present study waspartly supported by the Grants-in-Aids for
Scientific Research from the Ministry of Education, Science and Culture.

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pI. 1. (in Russian)Rauser-Chernoussova, D.M., 1938: Verkhnepaleozoyskie foraminifery Samarskoy Luki i Zavolzh'ya. Trudy Ceol. Inst., Akad. Nauk SSSR,
vol. 7, p. 69~167, pis. 1~9. (in Russian and Eng-

lish summary and description)- - , 1958: Opyt sverkhdrobnogo raschleneniya razreza verkhnekamennougol'nykh otlozheniy v
rayone Kuybyshevskoy GES. Akad. Nauk
SSSR, Trudy Ceo!. Inst., vol. 13, p. 121~138, pis.
1~2. (inRussian)_ _ , Beljaev, G.M. and Reitiinger, E.A., 1940: 0
foraminiferakh kamennougol'nykh otlozheniySamarskoy Luki. Trudy Neft. Ceol.-Razved.
Inst., nov. ser., vol. 7, p. 1~87, pis. 1~9. (in Rus-

sian and English summary and description)
Fursenko, A.V., 1959: Osnovy
paleontologii, Obschaya chast', Prosteyshie. 482- - andp., 13 pis. Izdatel. Akad. Nauk SSSR, Moskva.

(in Russian)- - , Ivanova, E.A., Grozdilova, L.P. and Makhlina,
M.Kh. (in collaboration with Alksne, A.E.,
Kireeva, G.D., Konovalova, M.B., Meyen, S.V.,
Morozova, J.P., Rozovskaya, S.E., Faddeeva,
I.Z., Shamov, D.F., Shchegolev, A.K. andShcherbakova, M.V.), 1979: The Upper Carboniferous Series. In, Wagner, R.H., Higgins, A.C.
and Meyen, S.V. eds., The Carboniferous of the
U.S.S.R. Yorkshire Ceol. Soc., Occ. Publ., no. 4,
p. 147~174.
- - , Kireeva, G.D., Leontovich, G.E., Gryzlova,
N.D., Safonova, T.P. and Chernova, E.I., 1951 :Srednekamennougol'nye Juzulinidy Russkoy
Platformy i sopredel'nykh oblastey. 380 p., 58
pis. Akad. Nauk SSSR, Inst. Geol. Nauk,
Minist. Neft. Promyshlennosti SSSR, Izdatel.
Akad. Nauk SSSR, Moskva. (in Russian)Rozovskaya, S.E., 1950: Rod Triticites, ego razvitie istratigraficheskoe znachenie. Akad. Nauk
SSSR, Trudy Paleont. Inst., vol. 26, p. I ~ 78, pis.
I ~ 10. (in Russian)- - , 1958: Fusulinidy i biostratigraficheskoe raschlenenie verkhnekamennougol'nykh otlozheniySamarskoy Luki. Akad. Nauk SSSR, Trudy
Ceol. Inst., vol. 13, p. 57~120, pis. 1~15. (in Rus-sian)
- - , 1975: Sostav, sistema i filogeniya otryada
Fuzulinida. Akad. Nauk SSSR, Trudy
Paleont. Inst., vol. 149, pis. 1~35. (in Russian)
Sada, K., 1967: Fusulinids from the Millerella Zoneof the Taishaku Limestone (Studies of the stratigraphy and the microfossil faunas of the Carboniferous and Permian Taishaku Limestone in west
Japan, no. I). Trans. Proc. Palaeont. Soc.
Japan, N.S., no. 67, p. 139~147, pis. 12~13.

__ , 1969: Microfossils of the lowest part of the
Taishaku Limestone (Ibid., no. 4). Ibid., no. 75,
p. 119~129, pis. 12~13.
__, 1972: Fusulinids of the Profusulinella Zone of
the Taishaku Limestone (Ibid., no. 2). Ibid., no.
87, p. 436~445, pis. 52~53.
__ , 1973: Permian fusulinid zones in the Taishaku
Limestone Upland, west Japan. Mem. Fac.

Cen. Educ., Hiroshima Univ., ser. 3 (Studies in
Natural Science), vol. 7, p. 25~33. (in Japanesewith English abstract)__ , 1975: Late Mississippian and early Pennsylvanian fusulinid faunas of the Taishaku Limestone in west Japan. Bull. Soc. beIge Ceol.,tome 84, fasc. I, p. 5~9.
- - , 1977: Primitive fusulinacean faunas in central
and western Japan. Mem. Fac. Integrated Arts
Sci., IV, Hiroshima Univ., vol. 4, p. 17~25.
- - , Nomura, K. and Oho, Y., 1984: Primitive
fusulinacea from Dangyokei of Taishaku(Studies of the stratigraphy and the microfossil
faunas of the Carboniferous and Permian Taishaku Limestone in west Japan, no. 5). Trans.
Proc. Palaeont. Soc. Japan, N.S., no. 134, p.
388~392, pI. 75.
- - and Yokoyama, T., 1966: Upper Permian
fusulinids from the Taishaku Limestone in west
Japan. Ibid., no. 63, p. 303~315, pis. 33~34.
- - and - - , 1970: Fusulinids of the Fusulinella
Zone of the Taishaku Limestone (Studies of thestratigraphy and the microfossil faunas of the
Carboniferous and Permian Taishaku Limestone
in west Japan, no. 3). Mem. Fac. Cen. Educ.,

Hiroshima Univ., ser. 3 (Studies in Natural
Science), vol. 4, p. 39~44, pI. 1.
Schellwien, E., 1898: Die Fauna des karnischen
Fusulinenkalks. Theil II: Foraminifera.
Palaeontogr., Bd. 44, p. 237~282, pis. 17~24.
- - , 1908: Monographie der Fusulinen, Teil I.
Die Fusulinen des russisch-arktischen Meeresgebietes. Ibid., Bd. 55, p. 145~194, pis. 13~20.
Scherbovich, S.F., 1969: Fuzulinidy pozdnegzhel'skogo i assel'skogo vremeni Prikaspiyskoy Sineklizy. Akad. Nauk SSSR, Trudy Ceo!. Inst.,
vol. 176, p. 1~82, pls.I~18. (in Russian)Sheng, J.Z. (Sheng, J.c.), 1958: Fusulinids from thePenchi Series of the Taitzeho valley, Liaoning.
Palaeont. Sinica, N.S.B, no. 7, p. 1~119, pis. I~
16.
- - ed., 1966: Fusulinids of China. 177 p., 27 pis.
Sci. Publ. House, Beijing. (in Chinese)- - , Min, Q.K. and Wang, L.L., 1976: Fusulinidzones of the Middle Carboniferous Huanglong
Limestone at Jinsigang near Nanjing. Acta
Palaeont. Sinica, vol. 15, no. 2, p. 196~2 10, pis.
I ~3. (in Chinese with English abstract)
Sun, X.F., Gao, C.X. and Zhang, X.L., 1983:

953.

Carboniferous fusulinaceans from Taishaku

Fusulinida. In, Xi'an Inst., Geol. Mineral
Resour. ed., Paleontological Atlas of Northwest
China, Shaanxi, Gansu and Ningxia vol., no.2
(Upper Paleozoic), p. 3-40, pis. 1- 10. Geol. Publ.
House, Beijing. (in Chinese)
Ueno, K., 1989: Carboniferous and Lower Permian
foraminiferal biostratigraphy in the Akiyoshi
Limestone Group (Studies of the Upper Palaeozoic foraminifers in the Akiyoshi LimestoneGroup, southwest Japan, Part I). Bull.
Akiyoshi-dai Mus. Nat. Hist., no. 24, p. 1-39, pis.
1-8. (in Japanese with English abstract)- - , 1991 : Upper Carboniferous fusulinaceansfrom the Akiyoshi Limestone Group, southwest
Japan. Trans. Proc. Palaeont. Soc. Japan, N.S.,
no. 163, p. 807-827.
Wang, Y.H., 1987: Late Carboniferous fusulinids in
middle and lower Yangtze valley. Bull. Nanjing Inst., Geol. Mineral Resour., Chinese A cad.
Geol Sci., vol. 8, no. 2, p.85-91, pis. 6-7. (inChinese with English abstract)- - , Wang, L.L., Wang, J.H., Zhu, Z.G., Lin, G.W.,
Zhang. L.Z. and Quian. Q .• 1982: Fusulinida.
In, Nanjing Inst.. Geol. Mineral Resour. chiefly
ed., Paleontological Atlas of East China. no.2
(Late Paleozoic). p. 5- 108. pis. 1-30. Geol.
Publ. House. Beijing. (in Chinese)
Watanabe. K., 1973: Profusulinella assemblage in theOmi Limestone, Niigata Prefecture. central Japan(Studies of Carboniferous fusulinacean of Omit
Part I). Trans. Proc. Palaeont. Soc. Japan,
N.S .• no. 92, p. 371-394. pis. 51-53.
- - , 1991,' Fusuline biostratigraphy of the Upper
Carboniferous and Lower Permian of Japan,
with special reference to the CarboniferollsPermian boundary. Palaeont. Soc. Japan, Spec.
Papers, no. 32. p. 1-150.
Wu, W.S .• Chang. L.H. and Ching. Y.K .• 1974: The
Carboniferous rocks of western Kueichow.
Mem. Nanking Inst., Geol. Palaeont., no. 6. p.

157

72-87. pis. 1-8. (in Chinese)
Xia. G. Y. and Zhang. Z.c.. 1985: Protozoa. In.
Tianjing Inst., Geol. Mineral Resour. ed.,
Paleontological A tlas of North China, no. I(Paleozoic vol.). p. 32-150. pis. 1-35. Geol. Publ.
House. Beijing. (in Chinese)
Xie, S.G .• 1982: Protozoa. In. Geological Bureau of
Hunan ed., The Palaeontological Atlas of
Hunan, Geol. Mem., ser. 2, no. I. p. 2-73. pis. 135. Geol. Publ. House. Beijing. (in Chinese)
Yokoyama. T.. 1959: The geology of vicinity of
Taishaku Gorge. Scientific Researched Reportsof the Proposed Site Seminational Park in
Chugoku Mountainland, Tottori, Shimane andHiroshima Prefectures, p.29-42. pis. 12-14. (inJapanese)
Zhang. L.X. (Chang. L.S.), 1963: Verkhnekamennougol'nye fuzulinidy Kel'pina i sopredel'nykh
oblastey Sin'tszyana (II). Acta Palaeont.
Sinica, vol. II. no. 2. p.200-227. pis. 4-9. (inChinese and Russian)- - . 1974: Carboniferous Fusulinida. In. NanjingInst. Geol. Palaeont. ed., Stratigraphical andPaleontological Atlas of West South China, p.
256-265. pis. 130-133. Sci. Publ. House. Beijing.
(in Chinese)- - and Jiang, R.C.. 1984: Weiningian fusulinids
from Tangshan city. Hebei. Acta Micropalaeont. Sinica, vol. I. no. 2. p. 138-142. pI. I.
(in Chinese with English abstract)- - , Zhou. J.P .• Niu, B.X. and Wang. H .• 1987:
Weiningian fusulinids from the Zibo area of
Shandong. Ibid .• vol. 4. no. 3, p.247-264. pis.
1-4. (in Chinese with English abstract)Zhou, T.M., Sheng, J.Z. and Wang, Y.J .• 1987:
Carboniferous-Permian boundary beds andfusulinid zones at Xiaodushan. Guangnan. eastern Yunnan. Ibid .• vol. 4, no. 2, p. 123-160. pIs.
1-6.

Akiyoshi f:kE'. Atetsu ~ilJm. Dangyokei 1t1T:i.~. Eimyoji 7k1j}j~. Hiroshima $.~. Huanglong (Huanglung) ~~. Omi 1fW. Taishaku 1irfR. Tojo Jlt!1ilt. Simotaishakukyou r1irfR~. Unata ~ml83. Uyamano ~Jll!l!t. Xinjiang ~iJli·~~B*, *~~~*~U~~-L~~~*~~$m:@mB*~*. 1irfRam~~~ml83~.m~K~~~~1ir~E~~~W$~ffi~7kIj}j~~.~~~~a~Jll!l!t~.r~~iIVJ~£R1=.~~>a:-~WL. 7k1j}j~~$~':' Fusulinella bingoensis *. Fusulina quasicylindrica*, Obsoletes cf. obsoletus-Protriticites ovatus * >a:-, .:t L -C~Jll!l!t~$~':' Triticites (Rauserites) stuckenbergi-Jigulites dagmarae *. Occidentoschwagerina chatcalica *>a:-~5E L t.:o~{~E*~)j\jj~£RW~ c .:c A ::1 - ~1uJ~. m~? =} Iv. '"~:tt!!.. $~ 7 -:/ 7. m~$
00 tJ: c'-c:m !?;h -C \" ~ )j\jj~£RW~ c ~ .l:ttUj'!?, Fusulinella bingoensis * c FUSlilina
quasicylindrica *i.l~ Moscovian f&:JtIJ~ Myachkovsky Horizon ~.:., Obsoletes cf. obsoletusProtritcites ovalllS * i.l~ M' :JtIJ Kasimovian ~.:. Triticites (Rauseries) slllckenbergi-Jiglilites
dagmarae * c. Occidentoschwagerina chatcalica *i.l~ Gzhelian ~.:..:t;h~;h~ .l:t"C· ~ ~'* ';/

0

.:.

158

Katsumi Ueno and Yoshihiro Mizuno

lDx;f .lti':' J: IJ, *mEB:tilit:glt-c'I;l::7k~~1! c *LlI!1lf1! 1:U~U:f9='-l:tm Kasimovian ~ Jz <7f~.s-I*H*-c':f£ L -c:to IJ, i t.:ftOIET -9='tm",",lv.b.
C ~ tL -C ~ ,t.:*LlI!1lfl!lD-{flH:l::PtJ:*<

C {, l:tmEilR7%-c';l; 0 ;:. C iI~~ I? ii' C tJ: -? t.:o *gfilj-c'1;!: 1 ~JTfi (Fusulinella bingoensis, sp,nov,) ~43-tr 11 ~ 16 filDitY5iiil1!.9"J&~~~Jl!I!:i- 0 C C {, i':', fJn!:r1*lD l:tm~~J1!-E JY(!6Jfu~-c'I;l:;:' tL i -c';l; i IJ J: <J!!.~1fo~tL -C l'f.i:"ll'-?t.: Fusulina 1* C .f:lDt}jiiill!;g$F~lD~I!rr;~

i't:J2;~jH':' "J ~'-C {,)$"';: 0 0

l:!IlfIl9J~ • 7J(!Ilfi;*

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 170, pp. 159-185, 9 Figs., June 30, 1993

954.

THE RELATIONSHIP BETWEEN BATHYMETRIC DEPTH
AND CLIMATE CHANGE AND ITS EFFECT ON
MOLLUSCAN FAUNAS OF THE KAKEGAWAGROUP,CENTRALJAPAN*
TAKAMI NOBUHARA
Department of Earth and Planetary Sciences, School of
Science, Nagoya University, Nagoya 464-01

Abstract. Seven types of molluscan assemblages are recognized in the muddy sand andsilt facies of the Plio-Pleistocene Kakegawa Group, central Japan. Both facies are continuously distributed throughout late Pliocene to earliest Pleistocene times. The assemblages
have species compositions comparable to the living faunas in upper sublittoral to bathyal
depths under influence of the Kuroshio warm current. I trace the temporal distributions ofspecies characteristic of each bathymetric zone. Groups of warm-water species in the upper
sublittoral zone disappeared in steps through the time interval considered in this paper. By
contrast, warm-water species in the lower sublittoral zone and Japonic endemic species in all
depths occurred throughout the interval. The assemblages of the lower sublittoral andbathyal zones show no marked changes through time, and are closely similar to those of thepresent sea off central Japan. Next, to confirm the cooling effect on organisms in eachbathymetric zone, I also compare temporal distributions between taxonomically close species
and specify the habitats of the disappearing species, the other ecological characters being
similar. The comparisons indicate that the cooling effect was restricted to the upper
sublittoral zone. The results reflect fluctuations of the thermal structure of the sea off central
Japan during Plio-Pleistocene time.
Key words. Kakegawa Group, Kakegawa fauna, molluscan assemblage, cooling of sea
water, water mass structure, Plio-Pleistocene.

Group yields abundant marine molluscan
fossils and many paleontological studies havebeen made since the descriptive works of
Yokoyama (1923, 1926) and Makiyama(1927). The molluscan fauna consists ofcommunities in an open sea condition. It iscalled "the Kakegawa fauna" and is wellknown in Japan as the late Pliocene-earliest
Pleistocene warm-water fauna of southwestern Japan.
Tsuchi (1961) showed a stratigraphic range
chart of representative molluscan species of
the Kakegawa fauna. On the basis of temporal changes in the fauna, Tsuchi (1961)
divided the Kakegawa Group into four

Introduction
The Plio-Pleistocene Kakegawa Group is
exposed in the western part of Shizuoka
Prefecture, central Japan. It is one of thetype areas of the Neogene series along the
Pacific coast of Southwest Japan. The standard sequence has been established on thebasis of planktonic foraminiferal biostratigraphy (e.g., Saito, 1960; Ibaraki, 1986a, b),magnetostratigraphy (Yoshida and Niitsuma,
1976; Ishida et al., 1980), and fission track
dating (N ishimura, 1977). The Kakegawa'Received August 6, 1992; revised
accepted March 22, 1992

manuscript

159

160

Takami Nobuhara

stages, the Totomian, Suchian, Kechienjian
and Yuzanjian, in ascending order. Many
warm-water species are abundant in the Suchian stage. They are characteristic speciesof the Kakegawa fauna, such as Amus-

siopecten praesignis, Venericardia panda,
Chlamys satoi, Turritella perterebra and soon. Some of these species declined during
the Kechienjian stage and most of themdisappeared during the Yuzanjian stage.
Moreover, some Japonic endemic genera suchas Suchium and Siphon alia show morphological changes at the subspecific or
specific level through these stages (Makiyama,
1925,1941). Tsuchi (1990) suggested thatthese faunal changes are related to cooling of
the sea water. These cooling events wererecognized also as temporal changes in theplanktonic foraminiferal assemblage of the
Kakegawa Group (Ibaraki, 1986b).
The stratigraphic range chart of the moll uscan species shown by Tsuchi (1961), however,focused on key species whose temporal distributions are restricted to particular stages. It
is not clear from his chart which species occur
throughout the four stages. Moreover,almost all of the key species used for therecognition of the stages occur mainly inshallow, marginal facies such as the Dainichi
Formation. With respect to the deep
offshore moll uscan fauna, Chinzei (1980)
described molluscan associations characteristic of lower sublittoral to upper bathyal
depths along an isochronous tuff layer inrocks ascribed to the Kechienjian stage.
Paleontological studies of the deep offshore
fauna, however, hav~ not covered all the
Kakegawa Group, and the temporal change
in the deep molluscan fauna has not beenstudied. Therefore, the relationship between
bathymetric depth and the cooling effect onmarine organisms has not been examinedpreviously.
In this paper, I examine the temporalchange of molluscan assemblages in each
depth zone from the Suchian to the Yuzanjian. I recognize seven types offossil moll us-

can assemblages. Their depositional environments range from a muddy sand bottom inthe upper sublittoral zone to a silt bottom inthe bathyal zone. I compare assemblages ofdifferent ages that were deposited at similar
depths and with similar bottom characters.
Morphological change at the subspecific level
through time, however, is beyond the scope of
this report, because I could not obtainenough specimens to study these forms
biometrically. This study focuses on tracing
the temporal distributions of species characteristic of each depth zone to make clear thethermal fluctuations of the sea water throughtime in each depth zone.

Acknowledgments
Thif. paper represents the main part of my
doctoral dissertation submitted to Nagoya
University. I wish to express my sincere
gratitude to Professor Junji Itoigawa (Nagoya
University) for his instruction and guidance
throughout this study. I would like to thankDrs. Tomowo Ozawa and Shinobu Mori
(Nagoya University) for their valuable comments, which helped improve this paper. I
wish to thank Dr. Alan Beu (the New
Zealand Institute of Geological and Nuclear
Sciences) for reading the manuscript criticallyand making a number of helpful suggestions.
I am indebted to Drs. Hiroshi Kitazato(Shizuoka University), Yasuo Kondo (Kochi
University) and Seiichiro Matsui (Utsunomiya University) for their important suggestions on several points. Thanks are also
due to Messrs. Atsushi Ujihara, Keisuke
Inoue, Takeshi Saito (Nagoya University),
and Dr. Hiroaki Karasawa (Nagoya University), and Mr. Hisanori Wakamatsu (Power
Reactor and Nuclear Fuel Develop Corp) for
their assistance in my field work. This
research was supported in part by a grantfrom Fellowships of the Japan Society for the
Promotion of Science for Japanese Junior
Scientists (No. 1664).

954.

Molluscan faunas of the Kakegawa Group

Geologic setting of collecting
localities
The upper part of the Kakegawa Group isascribed to the Suchian to Yuzanjian stages.
Its lithofacies changes laterally. That is, anorthwestern shallow-sea facies grades laterally into a southeastern deep-sea facies (Figures 1,2). The northwestern part consists of
the Dainichi Formation (fine to mediumgrained sand), the Ukari Formation (finegrained sand and muddy sand), and the Soga
Formation (gravels, fine to medium-grained
sand, and muddy sand), in ascending order.
The southeastern part consists of the Horinouchi Formation (alternating beds of sandand silt of turbidite facies), and the Hijikata
Formation (massive silt), in ascending order.

161

The vertical change in the lithofacies possibly
results from a global eustatic sea-level change
during the Plio-Pleistocene (Masuda and
Ishibashi, 1991). The middle parts of the
Ukari and Hijikata Formations are at theclimax of the transgression, and the Soga
Formation was deposited during the regressive phase.
Several tuff layers have been traced throughthe different lithofacies, forming key horizonsin the Kakegawa Group. Of these, theHosoya Tuff and the Soga Tuff are important
key beds in the upper part of the Kakegawa
Group.
The Hosoya Tuff (Tsuchi, 1961) is interbedded in the lower part of the Ukari Formationand the uppermost part of the Horinouchi
Formation. The tuff has been dated at 1.9

LEGEND
138°E
I~

Terrace deposits

Ell\iill Ogasa Group

o

D
D
D

(illi][j]DKakegawa Group
Soga Formation
Hijikata Formation

Ukari Formation
Dainichi Formation
Horinouchi Formation

Tamari Formation
tuff bed

Figure 1. (A) Index map of the Kakegawa area. (B) Geological map of the studied. area, showing
sampling localities. (C I )-(C3) Enlargement maps showing sampling localities near Ukan, Hosoya, andKakegawa City.

Takami Nobuhara

162

NW
UKARI
I

HOSOYASE
KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATA

I

I

I

I

I

so

~j?:{{H Ogasa Group (conglomerate)

D
D

D

Datum 23 (1.6Ma)

Soga Fm. (gravels, sand and muddy sand)Datum 22 (1.87Ma)

Hijikata Fm. (silt)

Datum 21 (1.9Ma)

Ukari Fm. (sand and muddy sand)Datum 20 (1.95Ma)I l Dainichi Fm. (sand)rnIIIIIl Horinouchi Fm. (all. bed of sand and silt)
Iii Tamari Fm. (silt)

(

o

I

2km

• sampling point

Figure 2. Schematic stratigraphic section of the upper part of the Kakegawa Group, showing the
distribution of the sampling localities. The time scale was compiled from the data of magnetostratigraphy(Yoshida and Niitsuma, 1976), fission track age (Nishimura, 1977) and planktonic foraminiferal biostratigraphy (lbaraki, 1986b).

F.T. Ma (Nishimura, 1977), and its magneticmicro biostratigraphical position is near thebase datum of Globorotalia truncatulinoides
and the base of the Olduvai event (lbaraki,
1986b). The Soga Tuff (Tsuchi, 1961) isintercalated in the middle part of the Soga
Formation and the uppermost part of the
Hijikata Formation. Tsuchi (1976) set theboundary between the Suchian and Kechienjian stages at the base of the Hosoya Tuff.
The deposits of the Yuzanjian stage are theSoga Formation and the correlative uppermost part of the Hijikata Formation.
According to Ibaraki's (l986b) planktonic
foraminiferal biostratigraphy, Datum 23 (thesecond coiling-direction change in Pulleniatina spp. from sinistral to dextral) is
clearly identified near the boundary between
the Kechienjian and Yuzanjian stages. Ibaraki (1986b) estimated the age of the datum at

1.6 Ma on the basis of correlation to themagnetostratigraphical time scale.
Muddy sand to silt facies are recognized inevery stage: through the Suchian to Yuzanjian, as shown in Figure 2. I have investigated the molluscan fossil assemblages of thesefacies, i.e., of the Ukari, Hijikata, and Soga
Formations. They yield abundant molluscs
that live today in upper sublittoral to bathyal
depths.
Brief description of the fossil
molluscan assemblages
have collected molluscan fossils from 77
localities (Figure I), and obtained 124 species
in 78 genera (listed in appendix tables 1-3).
Before describing fossil moll uscan assemblages, a few remarks should be made concerning modes of fossil. occurrence. Kidwell954.

Molluscan faunas of the Kakegawa Groupet at. (1986) defined the following terms on
fossil Occurrences: autochthonous assemblage (composed of specimens derived fromthe local community and preserved in life
position); parautochthonous assemblage(composed of autochthonous specimens thathave been reworked to some degree but nottransported out of the original life habitat) ;allochthonous assemblage (composed of specimens transported out of their life habitats
and occurring in a foreign substratum). In
the open sea such as the "Plio-Pleistocene
Kakegawa sea", shells, in particular, thoseliving in upper sublittoral depths under the
influence of storms, can be easily reworked
and transported. Consequently, some assemblages may be composed of specimens ofdifferent origins. According to Kidwell etat. (1986), they are referred to as mixed
a utoch tho no us-para u toch th 0 n 0 us,
para u toch tho n 0 us-aIl och tho n 0 u s, 0 r
autochthonous-allochthonous. It is difficult,however, to recognize autochthonous specimens because most of the species identified inthis study are shallow-burrowers or epifauna
which are easily reworked. Moreover, if an
assemblage contains several species in thesame matrix sediment and their habitat depths
are distinct from each other, it is difficult todecide whether the assemblage is an actual
ecotone between the different depths or amixed one containing shells transported fromdifferent depths.
Therefore, I classify occurrence modes
mainly into two types, namely "A-type" and"B-type," for convenience. In the A-type
occurrence, shells are randomly distributed in
the matrix sediment. Shell clusters are also
often found but the shells in the clusters aresupported by the sediment, which is nearly
the same as that around the clusters. Moreover, the species composition is compatible
with the sedimentary facies. Most of theshells are likely to be parautochthonous,
although some might have been transported
from different depths. The B-type is shellconcentrations in lenses and cl usters. In

163

contrast with the A-type, the sediments in thelenses and clusters are clearly discriminatedfrom the matrix sediment around them.
Moreover, the species composition of theshells is incompatible with the sedimentary
facies around them. The assemblages areclearly recognized to be allochthonous.
I classify fossil molluscan assemblages in
the A-type occurrence into seven types on thebasis of the occurrences of some dominant
species and/or characteristic species (Figure3). The depositional environments of theassemblages range from an upper sublittoral
sandy bottom to a bathyal muddy bottom.
Paleobathymetric interpretation is mademainly based on the habitat depths of living
species shown by Habe (1977) and Higo
(1973). Special attention is paid to theoccurrence modes of bathymetrically key
species whose habitats are nearly restricted to
one bathymetric zone: upper sublittoral
depths (e.g., Clementia papyracea, Dosinia
troscheli); lower sublittoral depths (e.g.,
Cryptopecten vesiculosus, Nemocardium
samarangae); bathyal depths (e.g., Limopsis
tajimae, Carinineilo carini/era). Moreover,the depositional environments of the assemblages are cross-checked by Ishibashi's (1989)
study on sedimentary facies in the Kakegawa
area, because there is close relationshipbetween the assemblages and the lithofacies.
I. Amussiopecten praesignis-Scapharca
castel/ata assemblage (Loc. U9-14A)
This assemblage is found in a slightly
muddy, fine sand bed, about 2.5 m thick, at
U9-14A. This sand bed is intercalated in
muddy sand of the lowermost part of the
Ukari Formation. This assemblage is characterized by abundant shells of Amussiopecten praesignis (Yokoyama) and Scapharca castel/ata (Yokoyama). Disarticulated shells of A. praesignis are distributed with their commissure planes parallel tothe bedding but the shells do not form acluster or bed. In contrast, S. castel/ata are
crowded together in large shell clusters, over
10 cm thick and about 50 cm long. The

Takami Nobuhara

164

occurrence in the Dalnichi Fm.
(nearshore facies)
Mode of occurrences andrepresentative species

Faciesj assemblage,. . . .. '. -C',:~gJI

\ Habitat depth: Cucullaea labiosa granulosa -lo 10-30"'Scaph~rca castellata..

upper
sublittoral
zone

-lo

;"r:-}'i, .,AmUSSlOpectenpraeslgms 14

1

I"! ... r'Am=iOI'?',,"p=,g""
"J--:

«(9
C

CU

+
+ 0-203· .. ~: Venericardia panda~.~ ·ID~: Clem~ntia papy'racea: ~.
I,Paphw schnellwna.:..-. . ~"'·~{e: Glycymeris rotunda· @ ~~j.,)lHe;CrenulilimoPsis oblonga

c-> .

e\

. .

E

r - - - - .___;Amussiopecten praesignis-" . <.....~ ____:Dosinia troscheIi:". .C" :'i~: Clementia papyracea(~~ c (e:paPhia schnelliana{ . r--->@",-;-Ventricolariafoveolata

I

41

e;

e:Glycymeris rotundae?.

---- - - - - - - - - - - -- -(:Cie;;,enti;p;py~a-c~; -- -r.,~')-;" ~ :Dosinia troscheli0)~ §~til..,Paphia schnelliana@.. - .-, e:Ventricolariafoveolata
411 - '" ~ "~I -:Glycymeri~ rotunda. ~ . -:r--.....t:Nemocardlum samarangae
Yoldia similis

l;

1-"""
"i (eiN='iO. -d I
~

E

~

-lo

2

ll.

ll.

50-2000+ 5-20+ 0-20+ 10-100+ 30-300

oCJ)
"0

-lo

Glycymens albolmeata.·e ~··~F\I e:Clenu:ntiapap~racea· .... -ill . e: Paphw schnellwna~ ~ c/';"Glycymeris rotunda

E

ll.

*.w,

····r··
Venericardia panda~>~.",g-,--:Crenulilimopsis oblonga
~

5
6

7

.~

: s

mngmjko:Para.bathy~oma
lueh;JorJi:Maldyamaw coreamca/,_~:Limopsis tajimae_-/"' ~~"Lirnopsis tajimae;. '- ~iNeilonelia coixr ~ - r "';v f,Maldyamc:ia coreanica@_ - ~_I_\!Fulgorana mentiens,-_ ~ -_ .~:,,"_I .iN'''",l/n:Ennucula niponica_ -_ I iCarinineilo carinifera_d _iBarySpira suavisv

Ii<JDEXlithofacies

1:~;Xd fine sand

1-_>1 muddy sandD.

.

coarse slit

1---1fine slit

1 Depositional

J. of living specie~ environments+ 10-100+ 30-300
50-2000++ 10-50+ 0-20+ 10-100
30-100+ 30-300

upper
sublittoralzone
orecotone between
upper and lower
sublittoral zone

ecotone between
upper and lower
sublittoral zone

+ 0-20+ 10-50+ 10-100+ 30-100
30-30050-300100-250+ 30-200

lower
sublittoralzone
shelf-edge+ 50-200
to100-250
100-800 uppermost bathyal zone

100-800
50-600100-250
100-300
50-60050-1460
100-600
100-500

bathyalzone

mode of occurrencee.

articulated'"'-

disarticulated~~Jshell cluster~~ebivalves

well preserved gastropods
abundant

Figure 3. Molluscan fossil assemblages in the A-type occurrence and their depositional environments. Square: schematic occurrence mode in vertical sections normal to the bedding plane.

954.

Molluscan faunas of the Kakegawa Groupshells of Scapharca are well preserved anddisarticulated or articulated. Some articulated shells are open. Many shells ofCrenulilimopsis oblonga (A. Adams) are also
found, both in the shell clusters and in thefine sand matrix. Cucullaea labiosa
granulosa Jonas, Venericardia panda (Y 0koyama) and Chlamys satoi (Yokoyama)
occur also in the clusters and/or in matrix
sand.
Except for Crenulilimopsis oblong a, most of
the component species live in the upper sublittoral zone and/or are commonly found inshell beds in the Dainichi Formation, whichcorresponds to nearshore facies of Ishibashi(1989). The lithofacies of this bed is slightly
muddy and seems to be transitional between
nearshore fine sand facies of the Dainichi
Formation and offshore massive muddy sandfacies of the Ukari Formation. These facts
indicate that this assemblage was formed inupper sublittoral depths, mixed with reworked shells such as Scapharca castellata.

2. Paphia schnelliana- Clementia papyracea- Glycymeris rotunda assemblage (representative localities: UlO-98, UI2-9, ST8)This assemblage occurs in a muddy sandfacies in the lower part of the Ukari Formation and in the Soga Formation. This
assemblage is characterized by common
articulated shells of Paphia schnelliana (Dunker) and Clementia papyracea Gray. In
particular, C. papyracea which lives today at
depths of 0-20 m (Habe, 1977) frequently
shows vertical, posterior-up shell position.
Glycymeris rotunda (Dunker) also occurs
abundantly, with its shells articulated at somelocalities (U 12-9, U 10-98). These species
are associated with many species living today
only in upper sublittoral depths, and withspecies found commonly in the shallow-water
Dainichi Formation; for example, Glycymeris albolineata (Lischke), A mussiopecten
praesignis (Yokoyama), Venericardia panda(Yokoyama), and Dosinia troscheli Lischke.
These shells are well preserved and are randomly distributed together with the dominant165

species. Species living In lower sublittoral
depths, such as Nemocardium samarangae(Makiyama), also occur at ST8 but only a few
specimens have been found.
The species composition and the autochthonous occurrence of C. papyracea suggestthat this assemblage lived in upper sublittoral
depths, or in depths transitional between theupper and lower sublittoral zones.

3. Crenulilimopsis oblonga- Glycymeris
rotunda assemblage (representative localities:
U8-138, U9-148, UI3-1, UI4-2A, STIO)This assemblage occurs in a muddy sandfacies in the lower part of the Ukari Formation and in the Soga Formation. This
assemblage is characterized by abundantarticulated shells of Glycymeris rotunda(Dunker) and Crenulilimopsis oblonga (A.
Adams), the latter of which is rare or absent
in the Paphia schnelliana- Clementia papyracea- Glycymeris rotunda assemblage described above. The two dominant species
are randomly distributed and also form manyloose clusters, up to about 15 cm in diameter.
This assemblage also includes many species
living only in upper sublittoral depths, or
those found in the shallow-water Dainichi
Formation, just as the Paphia-Clementia-Glycymeris assemblage does. They are
Amussiopecten praesignis (Yokoyama),
Babylonia elata (Yokoyama), Scapharca
species, Glycymeris albolineata (Lischke),
Clementia papyracea Gray, Dosinia troscheli
Lischke, and so on. Except for Glycymeris
rotunda and Crenulilimopsis oblonga, species
living in the lower sublittoral zone occur insmall numbers in this assemblage: for example, Cryptopecten vesiculosus (Dunker) at
U 13-1 and U 14-2A. The shells of associated species are well preserved and randomly
distributed as are those of the dominant ones.
The species composition suggests that thisassemblage lived in upper sublittoral depths
or in depths transitional between the upperand lower sublittoral zones.
4. Glycymeris rotunda- Ventricolaria
foveolata assemblage (representative local-

166

Takami Nobuhara

Itles: 4I-type; UI-I, UI-2, UI-3. 4I1-type;U2-8, U2-1O, U6-15A)
This assemblage occurs in the muddy sandof the Ukari Formation at many localities,
where the typical offshore facies of Ishibashi(1989) is exposed. Shells of both upper andlower sublittoral elements occur abundantly,
with random distribution. The shells also
form many fist-sized loose clusters or matrixsupported shell beds up to about 15 cm thick.
This assemblage is characterized by the dominance of Glycymeris rotunda (Dunker) and
Ventricolaria Joveolata (Sowerby). Commonly associated species are Paphia schnelliana (Dunker), Crassatellites takanabensis
Shuto, Nassarius siguijorensis (A. Adams),
Cryptopecten vesiculosus (Dunker),
Cycladicama cumingii (Hanley), andNemocardium samarangae (Makiyama).
Compared with the three assemblages described above, shells of lower sublittoral
species are common in this assemblage. The
shells of the dominant species, Glycymeris
rotunda and Ventricolaria Joveolata, are wellpreserved and many articulated specimens arefound. The two species are representativesof the lower shelf fauna burrowing in mud atpresent, at depths greater than 40 m in Sagami
Bay (Horikoshi, 1957).
This assemblage is subdivided into two
types. The first type, designated the "4I-type
assemblage", includes many species living inupper sublittoral depths as well as those living in lower sublittoral depths. For example, Amussiopecten praesignis (Yokoyama),
Clementia papyracea Gray, and Solecurtus
divaricatus (Lischke) occur at UI-I, UI-2
and UI-3. By contrast, the second type,designated the "4II-type assemblage" is associated with species living in shelf-edge
depths, such as Yoldia similis Kuroda et Habeat U2-8 and U2-1O. At some localities (U24, U2-5), however, many shells of the upper
sublittoral depths are mixed into a 4II-type
assemblage, and the species composition istransitional between the two types. With
respect to the distributions of the two types in

the Ukari Formation, the 4I-type assemblage
occurs in the uppermost part (earliest regressive phase) whereas the 4II-type assemblage
occurs in the middle part (climax of the transgressive phase).
This assemblage corresponds to the
Glycymeris rotunda- Venus Joveolata Association of Chinzei (1980). He stated that theassociation is characteristic of lower sublittoral depths. Moreover, he noted that the association in the most western part of the distribution area (the 4I-type assemblage) is estimated to be a biofacies transitional from theshallower-water assemblage of the Dainichi
Formation. It is estimated here that some
4I-type assemblages are parautochthonous
assemblages of an ecotone between the upperand lower sublittoral zones. Others, however, probably lived in lower sublittoral
depths and include some shallower-watershells transported from upper sublittoral
depths.
5. Nassaria magnifica assemblage (representative localities: U6-1, U6-11, STI3,
MKCW6)
This assemblage occurs in the coarse silt
facies of the Hijikata Formation. Wellpreserved shells of gastropods are disseminated sporadically in the massive silt with random orientation. Many gastropod shells
have protoconchs. This assemblage is characterized by gastropod shells markedly
exceeding bivalve shells in numbers of both
species and individuals.
Nassaria magnifica (Lischke) is dominant,associated with some other gastropods, suchas Parabathytoma luehdorfi (Lischke), Makiyamaia coreanica (Adams et Reeve), Bathybembix argenteonitens cf. hirasei (Taki etOtuka), Fulgoraria species, and by many
minute unidentified gastropods. Several
bivalve species characteristic of deep-sea
facies, such as Limopsis tajimae Sowerby andYoldia similis Kuroda et Habe, also are associated with this assemblage. This assemblage has a composition similar to the Nassaria magnifica Association of Chinzei

954.

Molluscan faunas of the K akegawa Group(1980).
The dominant species, Nassaria magnifica,
lives now at depths of 30-200 m and someassociated gastropods such as Parabathytoma
luehdorfi also have similar habitat depths(Higo, 1973). This assemblage, however,contains many shelf-edge to bathyal elements
such as Makiyamaia coreanica and Limopsis
tajimae in the same matrix silt sediment.
Moreover, the localities of this assemblage are
distributed in the sedimentary facies of slope
and basin plain shown by Ishibashi (1989).
Good preservation of the shells and theirrandom orientation in the matrix sedimentindicate that these species were not transported and mixed so far from distinct environments. Therefore, it is reasonable to consider that this assemblage lived at shelf-edge
to uppermost bathyal depths.
6. Limopsis tajimae assemblage (representative localities: U6-8, U8-3, UII-2,
MKCW7)
This assemblage occurs at many localities
in silt facies through the Suchian to Yuzanjian stages. It is characterized by dominant
Limopsis tajimae Sowerby. Abundant individuals of L. tajimae are disseminated in silt,with random shell orientation. The shells
are well preserved and many articulated specimens can be found. The assemblage hassome gastropods associated, such as Makiyamaia coreanica (Adams et Reeve) andFulgoraria mentiens (Fulton), and also somenuculoid shells, such as Neilonella coix Habe.
This assemblage corresponds to the Limopsis
tajimae Association of Chinzei (1980).
Most of the component species extend theirhabitat depths to the bathyal zone. The
sedimentary facies at the localities are thoseof slope and basin plain shown by Ishibashi(1989), although some gastropods such as
Nassaria magnifica which live at depths shallower than 200 m are included at some localIties. Kondo (1989) reported a dense population of Limopsis tajimae at depths of about
280 m in Suruga Bay. Therefore, this assemblage is likely to have lived in upper bathyal167

depths.
7. Nuculoids-dominant assemblage (representative localities: U9-3, UI2-5, STI2,
STl7, HYI)This assemblage is characterized by dominant nuculoid bivalves. The shells are scattered sporadically in the massive silt of the
Hijikata Formation. They are generally
well preserved and many are still articulated.
This assemblage has various dominant species
at various localities; for example, Acila aff.
divaricata (Hinds) at UI2-5, Ennucula
niponica (Smith) at STI2, Neilonella coix
Habe at U9-3, and Neilonella coix and N.
japonica Okutani at HY I. Other nuculoid
shells such as Carinineilo carini/era (Habe),
Bathymalletia inaequilateralis Habe, andNuculana spp. are commonly associatedforms. Several specimens of Limopsis tajimae Sowerby are found at U9-3. Somegastropod species also are associated at U 125 and HY I including Parabathytoma luehdorfi (Lischke), Euspira plicispira (Kuroda),
Makiyamaia coreanica (Adams et Reeve),
Bathybembix argenteonitens cf. hirasei (Takiet Otuka), and Baryspira suavis (Yokoyama).
Several unidentified small gastropods are also
found at every locality.
Most of the component species live inlower sublittoral to bathyal depths, according
to the present data of Habe (1977) and Higo
(1973). Hickman (1984), however, suggested
that dominance of proto branch bivalves is acharacteristic feature of deep-sea commumtles. Moreover, this assemblage occur inthe sedimentary facies of slope and basin
plain shown by Ishibashi (1989). Good
preservation of the shells and their randomorientation suggest that they are autochthonous to parautochthonous. These facts
indicate that this assemblages lived in bathyal
depths.
All the assemblages described above areplotted on the schematic stratigraphic crosssection (Figure 4). Their distribution isnearly concordant with the change in lithofacies demonstrating the transgressive-Takami Nobuhara

168

SE

NW
UKARI
I

KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATAHOSOYA

I

I

I

I

I

7"

assemblages in the B-type occurrence( ); transported shell composition

assemblages in the A-type oc,curre~lce'-':':::~~::....!:=====;----------~
1. Amussiopecten praesignis Scapharca castellata

4. Glycymeris rotUlula Ventricolaria Joveolata(41; I-type, 4II; II-type)

2. Paphia schnelliana - Clemelllia
papyracea - Glycymeris rotunda
3. Crenulilimopsis oblonga Glycymeris rotunda

Figure 4.

5. Nassaria magnifica
6. Limopsis tajimae
7. nuculoids - dominant

I

o

I

2km

Distributions of the molluscan assemblages.

regressive cycle described by Ishibashi (1989).
In Ishibashi's (1989) figure 13, the Ukari,
Hijikata, and Soga Formations correspond tothe offshore, slope and basin plain, and submarine channel facies, respectively. However, Aoshima (1978) suggested that foraminiferal assemblages in nearshore conditions are found in the basal and uppermost
parts of the Ukari Formation and in the Soga
Formation. The distributions of the foraminiferal assemblages nearly correspond to
those of the molluscan -assemblages of 1-,2-,3-, and 41-types in Figures 3 and 4. These
assemblages contain many species living at
upper sublittoral depths. In addition, someassemblages in the allochthonous B-type
occurrence also contain the shallow species.
Therefore, as shown in this figure, I obtainedmaterial of assemblages representing theupper sublittoral to bathyal zones in each of
the Suchian to Yuzanjian stages. Using thismaterial, I can trace the temporal distribu-

tions of species characteristic of each depthzone.

Temporal distribution of species
characteristic of each bathymetric
depth zone
In order to clarify the relationship between
bathymetric depth and cooling effect on themolluscan fauna, I pay attention to the relationship between the temporal distributionsof species and their habitats (geographicaldistribution and bathymetric depth).
The geographical distribution of eachspecies reflects its tolerance for sea watertemperature. For species that are still living,
I use the following terms for water regimes,
based on the data on their geographical distributions along the Pacific side of Japan (Habe,
1977; Higo, 1973; Kuroda and Habe, 1952) :"Kuroshio" (O'-34'N), "Kuroshio-Japonic"(O'-35'N), "Southwestern Japonic" (3l'N-35'

954.

Molluscan faunas of the Kakegawa Group0-25 0 •\'

Kuroshiowarm
current

J Japonic
SJ Southwestern Japonic
KJ Kuroshio - Japonic
K Kuroshio

Figure 5. Terminology of the water regimes(based on geographic distribution) of molluscs living
now on the Pacific coast of Japan. Courses of ocean
currents are compiled after Natural Astronomical
Observatory (1992).

N), and "Japonic" (31°N-42°N) (shown in
Figure 5). In this paper, the species occupying the first two regimes are called "warmwater elements" and those occupying the last
two are called "Japonic endemic elements."
F or extinct species, "warm-water .elements"
are defined as taxa whose distributions extend
to tropical regions such as Taiwan and Okinawa Island (e.g., Amussiopecten praesignis,
Venericardia panda), and "Japonic elements"
are defined as taxa whose distributions are
restricted to Japan (e.g., Mizuhopecten tokyoensis).
The habitat depths are inferred mainly
from the data of living species (Habe, 1977;
Higo, 1973). The data, however, are synthesized from various reports in the sea around
Japan and some species possibly had narrower depth ranges in the local "PlioPleistocene Kakegawa sea." Moreover, somespecies are extinct ones. Therefore, the interpretations on habitat depths are supplemented by the depositional environments of the169

assemblages in which the species occurs. In
order to avoid a vicious circle, the depositional environments are cross-checked by
the results of the sedimentary facies analysis(Ishibashi, 1989) and of the study on foraminiferal assemblages (Aoshima, 1978), as
noted before. The species whose habitat
depths are cross-checked by these data aremarked with "#" in Figure 6.
Figure 6 shows examples of the temporal
distributions of characteristic species in eachbathymetric depth at representative localities.
As noted in the introduction to this paper,
the temporal change in the Kakegawa fauna
is defined partly by the stepwise disappearance of warm-water species, and almost all of
those are found commonly in the shallowest
facies such as the Dainichi Formation. In
the Kechienj ian and Yuzanj ian stages, however, muddy sand to silt facies are the dominant fossiliferous lithofacies, instead ofshallow-water sandy facies such as the Dainichi Formation in the Suchian stage. In
order to confirm that the stepwise disappearance was caused by- cooling, I compare thetemporal distributions of many species within
the same muddy sand facies in each stage,
depositional conditions being nearly equal.
From each stage, Suchian to Yuzanjian, I
have collected species assigned to the assemblages which are considered to have lived ona muddy sand bottom in the upper sublittoralzone, or in transitional depths between theupper and lower sublittoral zones. The
assemblages are (1) the Amussiopecten
praesignis-Scapharca castellata assemblage,(2) the Paphia schnelliana-Clementia
papyracea-Glycymeris rotunda assemblage,(3) the Crenulilimopsis oblonga-Glycymeris
rotunda assemblage and (4) the Glycymeris
rotunda- Ventricolaria foveolata assemblage(4I-type). The localities of these assemblages
nearly correspond to the distribution of thenearshore foraminiferal assemblages shown
by Aoshima (1978). I trace the temporal
distributions of species that live now in uppersu b1ittoral depths or whose occurrences areTakami Nobuhara

170

I YUZANJIAN

KECHIENJIANSUCHIAN

stage

depth
Nassarius dorsalUs (ROding)
Piacamen spp.
Anisocorbula scaphoides (Hinds)
Dendostrea ? crenulifera (Sowerby)
It I Oblimopa japonica (A. Adams)#1 Paphia amobilis (Philippi)
Cucullaea labiosa granulosa loons
Solecurtus divaricatus (Lischke)~~b~~oral

Clemen ria papyracea Gray

Saccella confusa (Hanley)#1 TORno. [uteostoma (Kiister)
ttl Chlamys satoi (Yokoyama)#1 Venericarmapanda (Yokoyama)
1# I Amussiopecten praesignis (Yokoyama)
II 1 Scapharca castellata (Yokoyama)
Dosinia (Phacosoma) troscheli Lischke

K
K-KJ
K1
K1

10
10
10
10
10
10
10-1

'W
'W

'W
*J?

IHosoya tuff

10-0----------.-_____________......_._.A.._--_._._ .... -_ .....- - - - ._---_ ... _-- .. ---.. --_ .. _-------------------------_._-----------.--.,----0 -••.••- - - - - - - - - - - - -....... -......_.-.---.--__............

.----+-e-~,--_---_---------j--.--.

.........e -...

_ ...•--......

a fragment

Onustus exucus (Reeve)

KJ
KI

10
51

*2 Crenulilimopsis oblonga CA. Adams)#2 Glycymeris rotunda (Dunker)
I C.;ryplopeclen veSJCU osus \UUnker)
KI
S1
10~f.~ al Venlricolariafoveolalo CSowerby)
su I or
Nemocardium samarangae (Makiyama)
S1
Ennucula niponica (Smith)51*3 Bathymallena inaeqllilateralis Habe
51
Carinineilo carinifera (Habe)51
shelf
Neilonella colx Habe
51edge toUmopsis tojimae Sowerby
bathyalS1
5J
Baryspira suavis (Yokoyama)
Maldyamaio coreanica (Adams et Reeve) S1#3 Nassaria magnifica (liscbke)a fragment.-....-..-.......---.-...-......

I \a fragment.-.-.~ __. -... _ _ . , - - - - - - - - ......... e_+_... __ . - .•...•.....••........•.•_~ _ _. , - - - - ' , - - -, - - - - - . .
... - - - .• • • • u. . . . . . . . . . . . . . __ •······er:-···.'____ ....

,--------0-.--0----...--.----.. ----.. . --.----.-------..1.-----#1 Mizuhopecten IOkyoensis (5.S.) (Tokunaga) "'1#1 M. lokyoensis hokurikuensis<Masudta)"'J

upper toCycladicama cumingU (Hanley)lower
Nassarius siquijorensis CA. Adams)
sublittoral Paphia schnelliana (Dunker)

tSoga tuff~--------------------------------.~~.,----------_____ .. _...

-6---~e-.,~_ _ _ _ _ _ _ ...........................- - . . . . . . . _ __.....- . A .

..... - ..........._ _ _ _ _ _ ,. _ _ _•••- - - - -. . . . . . . . . .- . . . . . . .- -_ _- _ . - . -..._ _ . . . . . , . A .

. - -.........-.--------...---0-0---••- - - - - - - - < 0 - - - - - - - - - - - .
e-e-A ...
...-.- .......-..........
.....-...
....... - . . . .t.-e-e

~---

.....

.- •.• - ..... -.- .. - ... - ... - - . - . -..., - - - - - - - . - . . . . . . . - -...... - - - - - . - . , - - - -e-'",----------.--.--e··.-<0-•.- - - - - - - - - - - - - - -.......

-"'-.-.:=.::-~~-~~-~=:::...~::::============= ....--.--- .....

----...- -...-......- - - - -,-----~e---..-.--.-.o_------ - - - -__Figure 6. Temporal distributions of the species characteristic of each bathymetric depth. Supplementary interpretation on habitat depths: #1 = species which commonly occur in the Dainichi Fm. andwhose occurrences are restricted to the assemblages of 1- to 4I-types in Fig. 3; #2 = species which now livein lower sublittoral depths and the deeper zones but also occur abundantly in the assemblages of 1- to
3-types; #3 = species which now lives on the shelf but also occur abundantly in the assemblages of 5- to
7-types. Water regimes for living species: K, KJ, SJ, J (see Fig. 5); those for extinct species: 'W =warm-water; *J =Japonic. Fossil occurrence: circle =A-type; triangle = B-type.

restricted to the four assemblages noted above
and to the Dainichi Formation. They can beassumed to have been upper sublittoral
species.
The assemblages in rocks of the Suchianstage include many warm-water elements suchas Amussiopecten praesignis, Venericardia
panda, Paphia amabilis, Placamen spp.,
Oblimopa japonica, and so on. A. praesignis
and V. panda are found at most of the localities representing the Suchian stage. In particular, Amussiopecten praesignis is abundantat some localities (e.g., UIO-9B, U13-I).

Some warm-water elements such as Nassarius
dorsatus, Anisocorbula scaphoides, and Dendostrea? crenulifera are found only at UIO9B, but many individuals of these species
occur at this locality.
In rocks of the Kechienjian stage, some of
the warm-water species listed above are notpresent. For example, the Glycymeris
rotunda- Ventricolaria Joveolata assemblage(4I-type) at Ul-l contains many species living in upper sublittoral depths and abundant
shells of Amussiopecten praesignis, whereas
other warm-water elements such as Venericar-

954.

Molluscan faunas of the Kakegawa Group

Figure 7. Characteristic species of each bathymetric depth (I). upper sublittora l depths. la, b,
Nassarius dorsaLUs (Roding) , x O.9, ESN50013, Lac. UIO-9B ; 2, Oblimopa japonica (A. Adams) , X 1. 5,
ESN50014, Loc. UI3-2; 3, Paphia amabilis (Philippi), x O.68, ESN50015 , Loc. U9-14B ; 4, Clemen tia
papyracea Gray, X 0.9, ESN500 16, Loc. ST8 ; 5, A nisocorbula scaphoides (Hinds), X 0.9, ESN50017 , Loc.
UIO-9B ; 6, Cucullaea labiosa granulosa Jonas, x O.65 , ESN50018, Loc. U8-l3B; 7, Chlamys satoi(Yokoyama), x 0.72, ESN50019, Loc. U9-14A; 8, Venericardia panda (Yokoyama), x O.68, ESN50020,
Loc. UI3-1 ; 9, Amllssiopecten praesignis (Yokoyama), x O.68, ESN50021 , Loc. U8-l3B ; 10, Mizllhopecten tokyoensis hokllrikuensis (Masuda) , X 0.75 , ESN 50022, Loc. U 12-6B.

17 1

172

Takami Nobuhara

dia panda and Oblimopa japonica are absent.
This is possibly due to the slight difference indepositional environments between the 41type assemblage and the other assemblages of
the 1-, 2-, and 3-types in the Suchian stage.
At U2-11, however, an allochthonous assemblage transported from the upper sublittoralor shallower depths is present in the B-type
occurrence, but it contains no shells of Venericardia panda or Oblimopa japonica.
In rocks of the Yuzanjian stage, several
assemblages in the A-type occurrence arefound to contain many species that live now
in upper sublittoral depths. Their dominantand subdominant species are the same as
those of the Suchian assemblages, i.e., Paphia

schnelliana, Clementia papyracea, Glycymeris rotunda, and Crenulilimopsis oblonga.
The warm-water Suchian species that areabsent from the previous Kechienjian stage
also are not found in these shallow Yuzanjian
assemblages. Amussiopecten praesignis
occurs in this stage but only rarely, as a
fragment, whereas its well preserved shells areabundant in the Suchian and Kechienjian
assemblages.
As noted above, some warm-water elementsin the upper sublittoral assemblages
disappeared in steps. In contrast to this,some Kuroshio-Japonic species survived in
the upper sublittoral zone through threestages. They are Clementia papyracea,
Solecurtus divaricatus, Saccella confusa andTonna luteostoma. S. divaricatus was notfound in Suchian rocks in this survey, but
Yoshida (1981) repor,ted the species from theDainich'i Formation. Japonic endemic elements such as Dosinia troscheli also survived
in the upper sublittoral zone through all threestages.
With respect to species living in upper tolower sublittoral depths (or which live now inthe lower sublittoral and the deeper zones but
also occur abundantly in fossil assemblages of
1-,2-, and 3-types in Figure 3), both thewarm-water and the Japonic endemic elements also occurred throughout all threestages, as shown in Figure 6.
This continuous occurrence is true of
species living in lower sublittoral to bathyal
depths. Warm-water elements living inlower sublittoral depths, such as Cryptopecten
vesiculosus, are found in all three stages.
Japonic endemic elements also occurred
throughout the three stages. Besides the
species cited as examples in Figure 6, manyother Japonic elements in these depth zones
are found throughout the three stages, such as
Yoldia similis and Fulgoraria mentiens. Chinzei (1980) studied the deep offshore fossil
molluscan fauna in rocks of the Kechienjian
stage and stated that it mostly is composed of
species living now in waters off central Japan.
These deep-water faunas seem to have beenpoor in warm-water elements throughout thesequence, including the Suchian stage, as
shown in Figure 6. Some of the Southwestern Japonic living species, however, for example Makiyamaia coreanica, have been reported from the Shinzato Formation of Okinawa
Island by Noda (1980). It appears likely that
their geographical distributions in Pliocene
age were very similar to those of the fossil
warm-water elements. Whether the species
are warm-water elements or not, the species
compositions of the deep assemblages seem tohave been stable throughout the three stages.
Thus, the effect of cooling on faunal change
seems to have been restricted to the upper
sublittoral zone. Some problems, however,remain. First, the deep assemblages containmany minute unidentified gastropods whose
temporal distributions are not clear. Secondly, the effect of cooling on organisms
possibly differs not only with habitat depth,
but also with other ecological parameterssuch as food source and whether they are
infaunal or epifaunal. Therefore, in order toconfirm the effect of cooling in each bathymetric zone, I compare the temporal distributions of some taxonomically close species thathave similar ecological characters (life habits,
food sources) but lived at different depths
and/or in different water regimes. The com-

954.

Molluscan faunas of the Kak egawa Group

Figure 8. Characterist ic species of each bathymetric depth (2). la - 6, upper to lower sub littoral
depths ; 7- 9, lower subli ttora l depths ; 10- 15, shelf-edge to bathyal depths. la, b, Nassarius siquijorensis(A. Adams), x O.9, ESNS0023 , Loc. U3-4 ; 2a, b, Crenu/i/imopsis ob/onga (A. Adams), X I.S , ESNS0024,
Loc. UI0-5 ; 3, Paphia schnelliana (Dunker) , x O. 8, ESNS002S , Loc. U6-ISA ; 4, Cycladicama cumingii(Hanley) , X 0.9, ESNS0026, Loc. U2-3 ; 5, G/ycymeris rotunda (Dunker) , X 0.8 , ESN S0027, Loc. U 1-3; 6,
Onustus exutus (Reeve) , X 1.1 , ESN50028, Loc. Ogz l ; 7, Cryptopecten vesicu/osus (Dunker), x O.9,
ESNS0029, Loc. U2-1 0; 8, Venlrico/aria foveo/ala (Sowerby), X 0.9, ESNS0030, Loc. U 1-3 ; 9, Nemocardium samarangae (Makiyama) , x O.9, ESN50031 , Loc. UI-3 ; lOa, b, Limopsis tajimae Sower by, x O.9,
ESNS0032, Loc. U6-12 ; 11, Nassaria magnifica (Lisc hke), x O.9, ESNS0033, Loc. MKCW6 ; 12, Baryspira suavis (Yokoya ma), x O.9, ESNS0034, Loc. MKCW7 ; 13, Makiyamaia coreanica (Adams etReeve), x O.9, ESNS003S , Loc. MKCW6 ; 14, Ennucula niponica (Smith), X 1.2, ESNS0036, Loc. STI2 ;15, Neilonella coix Habe, X I.S , ESNS0037, Loc. U9-3.

173

174

Takami Nobuharapari sons reveal which bathymetric zone andwhich water regime the disappearing species
lived in, all other ecological factors beingnearly equal. The result can be regarded as a
typical faunal change for a cooling event,which can be applied to all faunal components.
Figure 9a-d shows four examples of thecomparison of temporal distributions at all 77
localities· in this survey. Life habit of eachexample species has not been confirmed
except for life positions of some species.
Superfamilies of bivalves, however, have tended to remain constant with regard to feeding
types throughout their histories (Stanley,1968). Therefore, the feeding types of thefollowing four species groups are mainly inferred based on the feeding categories ofStanley (1968, 1970).
I) "Limopsis" species (non-siphonate suspension feeders) (Figure 9a)
Three living species, Oblimopa japonica (aKuroshio-Japonic element), Crenulilimopsis
oblonga (a Japonic element) and Limopsis
tajimae (a Southwestern Japonic element)
occur abundantly at the localities where eachspecies is found. Kondo (1987) showed thatthese three species are semi-infauna (partly
exposed) and/or shallow burrowers (2-3 cm
beneath the surface).
Oblimopa japonica occurs in the Kakegawa
Group only in the Crenulilimopsis oblongaGlycymeris rotunda assemblage containing
many upper sublittoral species, although
Recent Oblimopa japonica has been recorded
from depths of 10-400 m (Habe, 1977).
Therefore, it is reasonably inferred that Oblimopa japonica lived in the upper sublittoralzone and did not live in the deeper zones inthe "Plio-Pleistocene Kakegawa sea".
Crenulilimopsis oblonga lives today in depthsof 50-2,000 m (Habe, 1977). The fossils of
this species occur widely in sublittoral tobathyal facies. In particular, the species is
one of the dominant species of the

Crenulilimopsis oblonga-Glycymeris rotunda
Limopsis tajimae lives In

assemblage.

depths of 100-800 m (Habe, 1977), and fossils
correspondingly occur in shelf-edge to bathyal assemblages (the Nassaria magnifica, theLimopsis tajimae, and the nuculoidsdominant assemblages).
Comparison of the temporal distributionsof these three species indicates that Oblimopa
japonica disappeared near the base of the
Kechienjian stage but that the other two"Limopsis" occurred throughout the threestages. That is, the warm-water element in
the upper sublittoral zone disappeared,
whereas the Japonic endemic elements in the
deeper zones survived.
2) Paphia species (infaunal siphonate suspension feeders) (Figure 9b)
The temporal distributions of two living
species, Paphia amabilis (a Kuroshio-Japonicelement) and P. schnelliana (a Southwestern
Japonic element), are compared in Figure 9b.
Their actual life habits have not been observed. It is, however, most likely that they are
shallow burrowers, because their shell outlines and pallial sinuses resemble those of
Ruditapes philippinarum (Adams et Reeve)
which has been confirmed to be an active
shallow burrower by Kondo (1987).
Both species live today in sublittoral depths(P. amabilis, 10-70 m; P. schnelliana, 10-100m) (Habe, 1977). Fossil P. schnelliana iscommonly found in every sublittoral assemblage and its fossil occurrence agrees with its
living depth range. By contrast, fossil P.
amabilis is found only in assemblages
containing many upper sublittoral species (inthe Amussiopecten praesignis-Scapharca castel/ata assemblage, the Crenulilimopsis
oblonga-Glycymeris rotunda assemblage, andsome allochthonous assemblages). P.
amabilis also occurs in the Dainichi Formation (Yoshida, 1981). This occurrence indicates that P. amabilis lived only at upper
sublittoral depths in the Kakegawa area during the Pliocene.
The temporal distributions of these species
indicate that P. amabilis disappeared near thebase of the Kechienjian stage but that P.

954.

Molluscan faunas of the Kakegawa Group

NW

SE
KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATAHOSOYA
I

UKARI
I

175

I

I

I

I

Hosoya Tuffwarm

* Oblimopa japonica
o Crenulilimopsis oblonga,pe' ,"bIlHOM'jlower sublittoral- Limopsis tajimaebathyal' - 1- - - ,o); allochthonous B-type

Figure 9.

G ~'I_

Comparison of the distributions of taxonomically close species.
9a. Distributions of "Umopsis" species.

NW

SE
KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATAHOSOYA
I

I

I

I* Paphia amabiliso Paphia schnelliana); allochthonous B-type9b.

Distributions of Paphia species.

I

176

Takami Nobuhara

schnelliana occurred throughout the threestages. That is, the warm-water element in
the upper sublittoral zone disappeared,
whereas the Japonic endemic element occurred throughout the stages.
3) "Chlamys" species (epifaunal suspension feeders) (Figure 9c)
The temporal distributions of two species,
Chlamys satoi (a fossil species) and
Cryptopecten vesiculosus (a living species) arecompared in Figure 9c. Chlamys species are
generally considered to be sessiles withbyssuses (Hayami, 1990). Hayami (19S4)
stated that Cryptopecten vesiculosus is almost
certain to lie on the sea floor with the left
valve facing up, like many other byssate
pectinids, on the basis of their behaviour inaquaria.
Both species, Chlamys satoi and
Cryptopecten vesiculosus, are warm-water elements. According to Masuda (1962),
Chlamys satoi occurs in Neogene rocks in the
Miyazaki area in Kyushu, at Miyako Island
in Okinawa, and in Taiwan, as well as in the
Kakegawa area. Cryptopecten vesiculosus
lives now at 50-600 m in the KuroshioJaponic water regime (Habe, 1977). Its fossil
geographical distribution extends from the
Neogene of Boso Peninsula southwards to theSumagui Formation in the Philippine Islands(Masuda, 1962). Therefore, both species
lived in nearly the same water regime during
the Pliocene. However, their fossil occurrences confirm that their habitat depths weredifferent in the Kakegawa area during
Pliocene time. Chlamys satoi occurs only
in upper sublittoral facies (in the Amussiopecten praesignis-Scapharca castellata andPaphia schnelliana-Clementia papyraceaGlycymeris rotunda assemblages). By contrast, Cryptopecten vesiculosus is common inlower sublittoral facies (the Glycymeris
rotunda- Ventricolaria Joveolata assemblage)
and occurs rarely in the transitional facies
between the upper and lower sublittoralzones (the Crenulilimopsis oblongaGlycymeris rotunda assemblage).

With respect to the temporal distributionsin the Kakegawa Group, Chlamys satoi
disappeared near the base of the Kechienjian
stage while Cryptopecten vesiculosus occurred
throughout the three stages. Although theoccurrence of C. vesiculosus in the Yuzanjian
stage is the allochthonous B-type, the abundance and good preservation of the shells
indicate that the species lived near the deposition site during the Yuzanjian stage. Thus,of these two Chlamydinae, only the upper
sublittoral species disappeared near the baseof the Kechienjian stage, although both
species are warm-water elements.
4) Species of Amussiopecten and Mizuhopecten (epifaunal suspension feeders) (Figure 9d)

Amussiopecten praesignis, Mizuhopecten
tokyoensis (s.s.) and Mizuhopecten tokyoensis
hokurikuensis occur at many localities.
With respect to their life habits, Hayami(1990) suggested that individuals of thesegenera can swim by clapping their valves
together.
Masuda's (1962) data on the geographicaldistributions of these species suggested that
Amussiopecten praesignis is a warm-waterelement and that Mizuhopecten tokyoensis(s.s.) and M. tokyoensis hokurikuensis are
Japonic endemic elements. The water
regimes of these species are different but theirliving depths are estimated to have been thesame (in the upper sublittoral zone) on thebasis of their fossil occurrences. That is,these species occur in assemblages containing
many upper sublittoral species (the Amussiopecten praesignis-Scapharca castellata
assemblage, the Paphia schnellianaClementia papyracea-Glycymeris rotunda
assemblage, the Crenulilimopsis oblongaGlycymeris rotunda assemblage, and the
Glycymeris rotunda- Ventricolaria Joveo/ata
I-type assemblage). Co-occurrence of Amussiopecten and Mizuhopecten was observed atmany localities (U 1-3, U 1-5, U2-11, US-13B,
U9-14A, UI2-6B, and UI2-SA).
Amussiopecten praesignis commonly occurs

954.

Molluscan faunas of the Kakegawa GroupNWHOSOYA
I

UKARI
1

177

SE
KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATA
I

I

I

I

* Chlamys satoi• Cryptopecten vesiculosus
1

1

o

2

Figure 9.

); allochthonous B-type

Comparison of the distributions of taxonomically close species. (continued)
9c. Distributions of "Chlamys" species.

NW
HOSOYA

UKARI

I

I

SE
KAKEGAWA KECHIENJI GANSHOJI SHIMOHIJIKATA
I

I

I

I

Hosoya Tuff*

Mizuhopecten tokyoensis (s.s.)... Mizuhopecten tokyoensis hokurikuensis

A2lower sublittoral
bathyalrl----,1o"ppe""bll.o't~); allochthonous B-type

911.

Distributions of Amllssiopecten and Mizllhopecten.

81

178

Takami Nobuhara

in rocks of the Suchian and Kechienjian
stages. In rocks of the Yuzanjian stage,
however, only one small fragment of thespecies was found in the Nassaria magnifica
assemblage at MKCW6. By contrast, Mizuhopecten tokyoensis hokurikuensis occurs at
many localities in rocks of the Suchian andKechienjian stages and many disarticulated
specimens were obtained at ST 10 (in rocks of
the Yuzanjian stage). Mizuhopecten tokyoensis (s.s.) rarely occurs in rocks of the
Kechienjian and Yuzanjian stages. Masuda(1962) suggested that Mizuhopecten tokyoensis hokurikuensis is an ancestral form of M.
tokyoensis (s.s.). Therefore, in the upper
sublittoral zone, Japonic endemic elements
survived through all three stages, whereas thewarm-water element is likely to havedisappeared early in Yuzanjian time.
The common pattern recognized in thesefour examples is that the warm-water elements
living in the upper sublittoral zone disappeared near the base of the Kechienjian stage or
early in the Yuzanjian stage. By contrast,
other species, such as the warmwater elementsin the lower sublittoral zone and Japonic
endemic elements in all depth zones, survived
through all three stages.
These examples therefore demonstrate thatthe cooling effect of the sea water on thefauna in the Kakegawa area is restricted tothe upper sublittoral zone.
Water mass fluctuation causing thefaunal change
The cooling of sea water recognized by thefaunal changes seems to have occurred incorrespondence with regressive phases recognized by the vertical change of the lithofacies.
It is most likely that the fluctuation of sea
water temperature associated with eustatic
sea-level change caused the faunal change.
The results noted above, however, suggestthat the cooling effect was restricted to theupper sublittoral zone and that the thermalchange in the deeper zones was too small tocause marked faunal change.
The kakegawa fauna was under the controlof the "paleo-Kuroshio warm current" in thesame way as the present southwesternJapanese marine fauna is controlled by the
Kuroshio warm current. It cannot be considered that the warm-water current vanishedand was replaced by a cool current, because
the Kuroshio-Japonic species, such as
Clementia papyracea, Nassarius siquijorensis
and Cryptopecten vesiculosus, continuously
occurred throughout the three stages from
Suchian to Yuzanjian, as shown in Figure 6.
The difference in the faunal change between
depths is most likely to be related to the water
thermal structure in the nearshore-offshore
area under the influence of the "paleoKuroshio warm current." Chinzei and Aoshima's (1976) isotopic analysis along tuff
layers in the Kechienjian stage showed thatthe water thermal structure at the earliest
Pleistocene was quite similar to that of thepresent-day Kuroshio water. Almost all of
the localities for their analysis, however,yields molluscan assemblages only under the
influence of offshore, oceanic water. Therefore, the conditions of the water masses in thenearshore sea need to be considered for discussion on this selective faunal change.
The nearshore facies of the Kakegawa area
was under the influence of coastal water
during both the Suchian and Yuzanjian
stages, as reported by Aoshima (1978).
According to him, the indicators of a coastal
water mass, such as a low percentage ofplanktonic foraminifera and low species
diversity of benthic foraminifera, can be recognized in the Dainichi Formation, in thebasal and uppermost parts of the Ukari Formation, and in the Soga Formation. The
localities indicating the influence of coastal
water nearly correspond to the localities
yielding upper sublittoral species in this survey. Therefore, the upper sublittoral fauna
is likely to have been under the influence ofthe coastal water. By contrast, lower sublittoral and bathyal species were under the954.

Molluscan faunas of the Kakegawa Groupinfluence of oceanic Kuroshio water, as suggested by Aoshima's (1978) foraminiferal
indicators.
Coastal water is distinguished from
offshore, oceanic water by its low salinity(Aoshima, 1978). According to Horikoshi(1987), coastal water is formed by the influxof fresh water from the land during summer,
when the water masses are strongly stratified.
Horikoshi (1987) stated that coastal water
covers the inner shelf in the summer but
disappears in winter, when the sea surface iscooled and the water conditions areconvectional. Conditions of coastal water
are controlled by various factors such as terrestrial climate (atmospheric temperature andamount of precipitation), and topography ofcoastline (embayment, gulf, or open sea).
Changes in such factors could have intensified
the effect of cooling associated with eustatic
sea-level changes and could have caused thedifference of the faunal change between
depths.
For example, the Japanese terrestrial climate deteriorated from a warm temperate to amore arctic one with severe winters during thelate Pliocene to early Pleistocene interval, as
shown in the terrestrial floral change inOsaka, Aizu, and Niigata areas by Suzuki andNasu (1988). During this interval, the Tertiary type plants, such as Metasequoia and
Glyptostrobus, disappeared in steps, and someboreal elements, such as Pinus koraiensis andPicea jezoensis, appeared for the first time.
Some problems still remain unsolved in correlations between marine sediments and terrestrial (and fresh water) ones, as noted by
Nakagawa (1988). The terrestrial floral succession, however, leads to one possible scenario for explaining the selective fluctuationof water masses, as follows.
During the Suchian stage (late Pliocene),
the terrestrial climate was warm-temperate
throughout the year. That is, the winterclimate was mild and the annual temperature
range was relatively small. Thus, winterconvectional conditions were difficult to initi-179

ate, and warm coastal water is estimated tohave covered the nearshore area all year
round.
By contrast, during the Kechienjian and
Yuzanjian stages (earliest Pleistocene), thewinter terrestrial climate became more severe
than in the Suchian stage. As a result, winter convectional conditions occurred in thenearshore sea and warm coastal water
disappeared during the winter. This change
in the water seasonality seems likely to have
had a more severe effect on organisms in theupper sublittoral zone than on those in thelower sublittoral zone, because upper sublittoral species had lived in the warm coastal
water stratified throughout the year during
the Suchian stage, whereas lower sublittoral
species were under the influence of offshore
Kuroshio water all year round, as they previously had been. This intensified seasonality
caused the faunal change in the nearshorearea.
This scenario focuses on coastal water conditions. On the contrary, it is possible toconsider that physical factors of the oceanic
Kuroshio water, such as current intensity,
primarily controlled the nearshore faunalchange. On a global scale, the current intensity is related to heat transport to the latitude.
On a local scale, more directly influenced by
the oceanic water current, an upper shelffauna contains more warm-water species, assuggested in Sagami Bay by Horikoshi (1957).
Therefore, changes of the current course also
could have influenced the faunal change.
At present it cannot be specified what thetrigger is which leads to the disappearance ofwarm-water species only in the upper sublittoral zone. More studies and investigations are needed, in particular on the interaction of the terrestrial climate and marine
climate in each depth zone and on thermal
structural changes in the Kuroshio current
along the vertical (depth) and horizontal(latitude) axes. The results of this paper on
faunal change, however, enable a start to bemade in understanding the fluctuation of theTakami Nobuhara

180

water mass structure associated with eustatic
sea-level change over a period near the
Pliocene/Pleistocene boundary.

Conclusions
1) Seven types of moll uscan assemblages
are recognized in muddy sand to silt facies of
the upper part of the Kakegawa Group.
Their depositional environments range from amuddy sand bottom in the upper sublittoralzone to a silt bottom in the bathyal zone, as
shown in Figure 3.
2) I traced the temporal distributions ofspecies characteristic of each bathymetric
depth zone. Some warm-water elements inthe upper sublittoral zone disappeared in stepin the earliest Pleistocene. By contrast,
warm-water elements in the lower sublittoralzone and Japonic endemic elements at all
depths occurred throughout the period fromthe late Pliocene to earliest Pleistocene.
3) To confirm the cooling effect on organisms in each bathymetric depth zone, I
compared the temporal distributions of taxonomically close species and specified thehabitats (bathymetric depth and water
regime) of the disappearing species, all other
ecological characters being similar. All four
examples indicate that the cooling effect on
faunal change was restricted to the upper
sublittoral zone.
4) It is most likely that the faunal change
was caused by the fluctuation of sea watertemperature associated with eustatic sea-levelchange, but the difference in the faunalchange between depths probably is related towater thermal structure in the nearshoreoffshore area. The results on the faunalchange give clues to the understanding of thefluctuation of water mass structure associatedwith eustatic sea-level change over a period oftime near the Pliocene/Pleistocene boundary.

References
Aoshima, M., 1978: Depositional environment of the

Plio-Pleistocene Kakegawa Group, Japan - acomparative study of the fossil and the Recent
foraminifera. Jour. Fac. Sci.• Univ. Tokyo. Sec.
2. vol. 19, p.401-441.
Chinzei, K., 1980: Moll uscan fauna of the PlioPleistocene Kakegawa Group; Its compositionand horizontal distribution. Mem. Natn. Sci.
Mus., Tokyo, no. 13, p. 15-20. (in Japanese withEnglish abstract)__ and Aoshima, M., 1976: Marine thermal structure of the Plio-Pleistocene warm water in central
Japan. Jour. Fac. Sci.• Univ. Tokyo. Sec. 2. vol.
19, p. 179-203.
Habe, T., 1977: Systematics of Mollusca in Japan.
Bivalvia and Scaphopoda. 372 pp. Hokuryukan,
Tokyo. (in Japanese)
Hayami, I., 1984: Natural history and evolution of
Cryptopecten (a Cenozoic-Recent pectinid
genus). Univ. Mus .• Univ. Tokyo. Bull., no. 24,
p. 1-149, pis. 1-13, I col.pl.
--,1990: "Mesozoic marine revolution" and evolution of bivalves. Fossils, no. 49, p.23-31. (inJapanese)
Hickman, C.S., 1984: Composition, structure, ecology and evolution of six Cenozoic deep-watermollusk communities. Jour. Paleont., vol. 58,
no. 5, p. 1215-1234.
Higo, S., ed., 1973: A catalogue of molluscan faunaof the Japanese Islands and the adjacent area.
58 + 397 + 61 p. BioI. Soc. Nagasaki Prefecture.
(in Japanese)
Horikoshi, M., 1957: Note on the molluscan fauna of
Sagami Bay and its adjacent waters. Sci. Rep.,
Yokohama Natn. Univ., Sec. 2, no. 6, p.37-64,
pI. II.
- - , 1987: Viewpoints as to sea. In, Horikoshi,M., Nagata, Y. and Sato, T., Nature in Japan.
vol. 7, Sea around Japan. p. 1-10. Iwanami
Shoten, Tokyo. (in Japanese; title translated)
Ibaraki, M., 1986a: Planktonic foraminiferal datum
levels recognized in the Neogene sequence of the
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92, p.119-134. (in Japanese with English
abstract)- - , 1986b: Neogene planktonic foraminiferal biostratigraphy of the Kakegawa area on the Pacificcoast of central Japan. Rep. Fac. Sci. Shizuoka
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Kidwell, S.M., FUrsich, F.T. and Aigner, T., 1986:
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Yoshida, T., 1981: Molluscan fossil assemblages
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327-340. (in Japanese with English abstract)*-

Shizuoka ~~, Kakegawa JrttJII, Ukari *:1-11. Hosoya *«l:fi., Ogasa 'J'!'l., Dainichi
B, Sogaii~, Horinouchi j;IHlz.F9, Hijikata ±:1J, Totomi )lIT, Suchi }i!ij~, Kechienji t.5~~,

Takami Nobuhara

182

Yuzanji mHll~!¥~-~~*1EmJIIJ!~.imJ§l.~~~(J)7l<;*~IJ,:~t:~j~i&lf~: tf~-~~®'tJ:::ifIlm)IIJfill'fO)1i'YtJr,~ -i'FG~Jfi l: I) i£-t Q 7 '00) J't 1~Ell'f~~ ~~,'ijlj L t-:o {-.:h G O)ll'f~O)'ct,\l'!J~Jta
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ilffi.~~~0)ll£1~~ lXll!k: Vn, Q >b 0) ~ ~ X. G.:hQ o~!*.~Appendix tables 1-3.

R=I-2, F=3-4, C=5-9, A=IO-19, VA=20-, in number of

List of molluscan fossils at representative localities.
specimens.
A·typemode of occu rrence
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localities< co3:! ~ C( 00stage~ C\, 0.....
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Bathybembu argenteonitens (s.s.) (Liscbke)
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B. argenreonilens fonna convexiusculus (Yokoyama)B. sp.
"Tristichotrochus" sp.
-S-uchium sucniense suchiense (I oKoyama)
S. suchiense subsuchiense (Malciyama)S. giganteum (Lesson)
S. cf. myscicum (Yokoyama)
S. obsoletum arenarium (Makivama)>-

Makiyamaia coreanica (Adams et Reeve)
M. subdeclivis (yokoyama)

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O. sp.A
Onustus exutus (Reeve)
Valva volva habei Oyama
Euspira pliclspira (Kuroda)
Tonna luteostoma (Kiister)
Neptunea kuroshio Oyama
B~bvlonia elata (Yokoyama)lB. e ata var.
Siphonalia declivls declivis Yokoyama
S. declivis biconica Makiyama
S. declivls subsp.
S. tonohamaensis totomiensis Makiyama
S. miJauio Melvill
S. modificata (Reeve)
S. spadicea (Reeve)
S. trochula (Reeve)
S. snn.
Nassaria mag nijU:a (Lischke)N. sp.
Nassarius (Zeuxls) siquijorensis (A. Adams)N. (l.) dorsatus (Reding)
Granuiifusus cf. nipponicus (Smith)
IG. Idranus Sliuto
Uromitra nakamurai Makiyama
Baryspira albocallosa (Liscbke)
B. urashima Kira
B. suavls (Yokovarna)
111. sp.
Fu/goraria totomiensis Makiyama
F. prevosriana (Crosse)
F. menciens (Fulton)roderiF. concinna
F. c. irasei (Sowerby)
F. spp.
Marginella (Stazzania) flaccido. (Yokoyama)

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mode of occurrence
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localities3
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speciesGemmula totamieruis (Makiyama)
Parabathytoma luehdorfi (Lischke)I1zatcheria sp.
•
Nipponoscaphander cumingii (A. Adams)
N. teramachii (Habe)
IFissidentalium YOKoyamai Makiyama
Spadentalina tubiformis (Boissevain)
Entalia quadrangularis Boissevain
Nucula sp.
Lamellinucula tokyoensis (yokoyama)
IL sp.
Acila aff. divaricata (Hinds)
A. minuta Makiyama
A. sp.
Ennucu[a nloonica (Smith)E. cyrenoides (Kuroda)
E. sp.
Sarepta japonica A. Adams"S.· sp.
Bathymalletia inaequilateralis Habe
1Carinineilo carinifera (Habe)
Neilonella colx Habe
N. japonioca Okutani
N. sp.
Nuculana~ula sadoeruis (Y ok~ama)
1N. yokoyama, (Kuroda)
N. yo/wyamai arai Habe
N. acinacea Habe
N. sp.
SacceIia confosa (Hanley)IS. gordonis (Yokoyama)
S. semateruis (Suzuki et Isizuka)
S. sp.
Yoldia naganumana (Yokoyama)
Y. similis Kuroda et Habe
IY. cf. gIauca Kuroda et HabeY. sp.
Portiandiajaponica (Adams et Reeve)
P. lischkei (Smith)
Scapharca castellata (Yok"Y"ffia)
Is: ct. castellata (Yokoyama)
S. suzukii (Yokoyama)S. broughtonii (Schrenck)
Cucullaea labiosa granulosa Ionas
Glycxmeris rotundo (Dnnker)
IG. albolineafli\[iSille)
Tucedlla pilsbry (Yokoyama)
Umopsis tajimae Sowerby
Crenulilimopsis oblonga (A. Adams)
Oblimopajaponica (A. Adams)

B-typeA-type2'" en IZl
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Solamen spectabilis (A. Adams)
Ctenamusium clancularium (Yokoyama)
Bathyamussium jeffreysi (Smith)Chlamys satoi (Yokoyama)C. cf. asDerulata Adams et Reeve
Cryptopecten vesiculosus (Dunker)
Amussiopecten praesignis (Yokoyama)
Mizuhopecten tokyoensLs (s.s.) (Tokunaga)
M. IOkyoensis hokurikuensis Masuda
Yabeoecten tokulI(lRai (yokoyama)
Anomia chinensis Philippi
Acesta goliath (Sowerby)
Limatula vltufivostokensis S=lato
Dendostrea ? crenul~~a ~~owerby)
Lucinoma annulata eeve
Cycladicama cUlllingii (Hanley)
Venericardia pando (Yokoyama)
V,ferruginosa (Adams et Reeve)
Pleuromeris pygmaea Kuroda et Habe
Indocrassatella obloneata'(Yokoyama)
Crassatellites takanabensis Shuto
C. uchidanus (Yokoyama)'Nemocardium samarangae (Makiyama)
Lurraria maxima Jonas
AnQulus vestalioides (Yokoyama)
Abra maxima Sowerby
A. soyoae Habe
A. sp.
Gari anomala (Deshayes)
G. siboeai Prashad
G. sp.
Solecurtus divarieatus (Lischke)S. sp.
~~:g.fi~rdonis Yokoyama"us" sn,Meiocardia tetragona (Adams et Reeve)
Ventrieolariafoveolata (Sowerby)
Mercenaria yokoyamai (Makiyama)
Pitar sp.
Dosinia·(Phacosomal 'aDoniea <Reeve)
D. (P.) troscheli Lischke
D. sp.
Paphia amabilis (Philippi)
P. schnelliana (Dunker)
Callisto chinensis -iHolten)
Clementia papyracea Gray
Anisocorbula scaphoides (Hinds)
Solidieorbula erythrodon (Lamarck)
Panopea japonica A. Adams
Periploma plane Ozaki

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Trans. Proc. Palaeont. Soc. Japan, N.S., No. 170, pp. 186-211,13 Figs., June 30,1993

955.

MORPHOLOGY AND TAXONOMY OF SOMEJAPANESE HEMICYTHERIN OSTRACODA- - WITH PARTICULAR REFERENCE TO
ONTOGENETIC CHANGES OFMARGINAL PORES - - *TOSHIAKI IRIZUKI
Institute of Geology and Paleontology, Faculty of Science,
Tohoku University, Sendai, 980

Abstract. Hemicytherin ostracodes are diverse in late Neogene deposits and include
some forms occurring in both the northern Atlantic and northwestern Pacific. To clarify
phylogenetic relations among these hemicytherin ostracodes, 21 species in eight genera(Baffinicythere, Daishakacythere n. gen., Finmarchinella, Hemicythere, Johnnealella, Normanicythere, Patagonacythere, and Urocythereis ?) are subjected to a morphological investigation of such characters as reticulation, muscle scars, hingement, and pore canals. The
present study demonstrates for the first time that ontogenetic changes of marginal pores,
which are distributed along the anterior valve margin, provide useful information about the
taxonomy of hemicytherin ostracodes and their phylogenetic reconstruction. On the basisof ontogenetic changes of distributional patterns both of normal and marginal pores, theexamined species can be divided into three groups. One new genus, Daishakacythere, andtwo new species, Finmarchinella subrectangulata and Patagonacythere sasaokensis, aredescribed herein.
Key words.
Japan.

Ostracoda, Hemicytherinae, ontogenetic change, marginal pore, Northeast

believes, that a genus is a group of species
which have morphological characters moresimilar to each other than to species of othergenera. Those characters should be
genetically controlled (not ecophenotypiccharacters) and homologous. In the taxonomic work of ostracodes, a common practice has been to rely mainly on the ornamentation and morphology of carapaces in theadult stage. We cannot determine, however,whether similarities between the comparedcharacters are derived from adaptive convergence (analogy) or phylogenetic descent(homology), on the basis only of adult morphology. Actually, some ostracodes belonging to phylogenetically different genera
become more similar in shape to each other

Introduction

The subfamily Hemicytherinae comprises anumber of genera, which have been definedon the basis of different characters bydifferent workers. Some ostracodologists
describe their genera in a narrow sense, thus it
is not unusual that one genus contains only
one species (monotypic genus). In addition,
there are a number of endemic sublittoral
ostracode species because of the absence ofplanktonic larval periods. As a result, many
genera have been proposed by ostracodeworkers in various regions of the world. It is
generally regarded, and the author also
'Received November II, 1992; revised manuscript
accepted March 22, 1993
186

955.

Morphology of hemicytherin Ostracoda

toward adulthood due to allometric elongation of male valves or inflation of female onesof nearly all species to accomodate the copulation apparatus. Thus, it is important toinvestigate ontogenetic changes and trajectories of characters to distinguish
phylogenetically related species groups (genera). Hemicytherin ostracodes have many
advantageous characteristics for studying
morphologic ontogenetic changes: relatively
large and heavily calcified valves which fossilize easily, numerous pore canals on the valve,straight pores along the valve margin, conspicuous reticulation, ridges, well developed
hingements, and muscle scars. These qualities facilitate the taxonomy and phylogenetic
reconstructions of hemicytherin ostracodeswith reference to ontogenetic changes.
The purpose of the present study is toreevaluate some characters which have been
considered important for ostracode taxonomy, and to demonstrate that distributional
patterns of marginal pores through ontogeny
are very useful for the taxonomy and understanding the phylogeny of hemicytherin
ostracodes.

Materials
Many hemicytherin ostracodes except for
the tribe Aurilini have been reported mainly
from Plio-Pleistocene deposits in Northeast
Japan (Cronin and Ikeya, 1987; Hanai and
Ikeya, 1991; Hanai and Yamaguchi, 1987;
Hanai et al., 1977; Hayashi, 1988; Irizuki,
1989; Ishizaki and Matoba, 1985; Okada,
1979; Tabuki, 1986). Among these
ostracodes 21 species were discriminated, including one new genus and two new species
which are described in this paper (Figure 2).
Figure 1 and Table 2 show the location ofsamples used in this paper. Most of thematerials were collected by the author, butsome were borrowed from others. In thepresent study, examined were such charactersas reticulation, pores distributed on the valve
surface and along the anterior valve margin,

187?

29 0kmFigure 1. Sample localities in northern Japan.
1 : off Hamatonbetsu, 2: Setana Formation, 3:
Funka Bay, 4: Hamada F., 5: Daishaka F., 6:
Shitazaki F., 7: Fujikotogawa F., 8: Anden F., 9 :Shibikawa F., 10: Sasaoka F., II: Tentokuji F.,
12: Otsuchi Bay, 13: Toyama Bay, 14: Omma F.
M: Miocene, N: Pliocene, P: Plio-Pleistocene, Q:
Pleistocene, R: Recent

muscle scars, and hingements of the species as
defined by previous workers. Examinations
show that the following assortment is reasonable for further study.
B affin icy there : Three species (B. sp. 1, B.
sp.2 and B. sp. 3) were discriminated in thisgenus. B affin icythere sp. 3 is identical with
B. howei of Cronin and Ikeya (1987). These
species will be described in another paper.
Finmarchinella: Five species (F. hanaii
Okada, F. japonica (Ishizaki), F. nealei
Okada, F. rectangulata Tabuki and F.
uranipponica Ishizaki) and a new species (F.

188

Toshiaki Irizuki

subreetangulata) to be described herein weredistinguished.
Hemieythere: Four species (H. emarginata (Sars), H. kitanipponiea (Tabuki), H.
oehotensis Schornikov, and H. orientalis
Schornikov) are placed here. Hemieythere
emarginata was placed in the genus
Baffinieythere by Hazel (1967) and Hemieythere kitanipponiea was described as Ambostraeon kitanipponiea by Tabuki (1986).
Patagonaeythere: Patagonacythere robusta Tabuki and a new species (P. sasaokensis)
which is described in this paper were distinguished.
Normanieythere: One species (N. japoniea
Tabuki) was determined.
"Uroeythereis": In the present study, agroup of taxa which has loosely been assigned
to "Uroeythereis" was divided into threedifferent genera: Johnnealella (J. nopporoensis Hanai and Ikeya), Uroeythereis? (U.?
gorokuensis Ishizaki), and the new genus
Daishakaeythere (D. abei (Tabuk i), D. posteroeostata (Tabuki) and D. sp. 1). These
revisions will be justified based on the following analyses.

Reevaluation of some importantcharactersFirst the author discusses reevaluation ofvalve characters such as reticulation, muscle

scars, and hingements, which have been considered to be of phylogenetic significance andimportant for ostracode taxonomy.
a)

Reticulation

Reticulation is an ornamentation resembling the mesh of nets which covers most of
the valve surface. Okada (1981, 1982a, b)
showed that each fossa corresponds to theunderlying epidermal cell. Patterns of reticulation have been used in taxonomy andphylogenetic analyses (Liebau, 1969, 1971,
1977 (English version 1971); Benson, 1972,
1977; Valicenti, 1977). In the present study,
Liebau's (1969) system was followed as faithfully as possible to examine 13 species having
prominent reticulation patterns: B. sp. 1, B.
sp. 2, B. sp. 3, D. abei, D. posteroeostata, F.
japoniea, F. nealei, H. emarginata, H.
kitanipponiea, H. ochotensis, U.? gorokuensis, J. nopporoensis, and P. sasaokensis. Figure 3 shows the location of c-type pores(Hanai and Ikeya, 1991) and fossal patternson the left valve of Baffin icy there sp. I.
Alphanumerals are keyed to those in Liebau's system. It is surprising that all the illustrated pores are located at homologous positions relative to those of Limburgina andOertliella, both belonging to the Trachyleberidinae (see Abb. 1 of Liebau, 1969). Therefore, the position of c-type pores provides an
excellent guide to determining homologous
fossae among species. As a result, all the~ Figure 2. Twenty-one species examined in this study. All figures are SEM micrographs of rightvalves in lateral view. Scale bars are 0.5 mm: A for 1-6, 17-21; B for 7-16.1, Baffinicythere sp. I, male,
Lac. PSK-7, IGPS 101616; 2, Baffinicythere sp. 2, male, Lac. 914-5, IGPS 101627; 3, Baffinicythere sp. 3,
male, Lac. St. 31, IGPS 101639; 4, Daishakacythere abei (Tabuki, 1986), gen. nov., male, Lac. 523-6, IGPS
101655; 5, Daishakacythere posterocostata (Tabuki, 1986), gen. nov., male, Lac. MAE-3, IGPS 101664; 6,
Daishakacythere sp. I, gen. nov., A-I stage, Lac. MAE-3, IGPS 101673; 7, Finmarchinella hanaii Okada,
1979, male, Lac. 523-6, IGPS 101706; 8, Finmarchinella japonica (Ishizaki, 1966), male, Lac. 523-6, IGPS
101715; 9, Finmarchinella nealei Okada, 1979, male, Lac. 523-6, IGPS 101723; 10, Finmarchinella rectangulata Tabuki, 1986, male, Lac. SK-3, IGPS 101732; 11, Finmarchinella subrectangulata, sp. nov., male,
Lac. 523-6, IGPS 101740; 12, Finmarchinella uranipponica Ishizaki, 1969, male, Lac. 523-6, IGPS 101749;
13, Hem icy there emarginata (Sars, 1865), male, Lac. PSK-5, IGPS 101758; 14, Hemicythere kitanipponica(Tabuki, 1986), male, Lac. SK-3, IGPS 101767; 15, Hem icy there orientalis Schornikov, 1974, male, Lac.
523-6, IGPS 101784; 16, Hemicythere ochotensis Schornikov, 1974, male, Lac. SK-3, IGPS 101775; 17,
Johnnealella nopporoensis Hanai and Ikeya, 1991, male, Lac. 523-9, IGPS 101800; 18, Urocythereis?
gorokuensis Ishizaki, 1966, female, Lac. HIR-2S, IGPS 101792; 19, Norman icy there japonica Tabuki, 1986,
adult, Lac. TAI-2S, IGPS 101808; 20, Patagonacythere robusta Tabuki, 1986, male, Lac. KOS-3S, IGPS
101815; 21, Patagonacythere sasaokensis, sp. nov., male, Lac. HIR-3S, IGPS 101823.

955.

Morphology of hemicytherin Ostracoda

189

Toshiaki Irizuki

190..::::.

".

-.

\,:·:\'<.··! .... :::::: ...._' '-. ... ::, ..:i.:( ......

-

,

..
~
~-.~
.... ...~"~~.~.,..~....~..~~------~~
.. ~
....~
... ~.,--------~~~'.~
... ~
... ~
...~.

Figure 3. C-type pore canals and reticulation in Baffinicythere sp. I (male LV), following Liebau's(1969) system. Scale bar is 100,u m.

examined species have almost the same reticulation pattern as shown in Figure 3, although
they show some variation in the posterodorsal
portion at the L2 and 03 fossae: the former
is often subdivided further and the latter is insome cases not divided even within the same
species. In comparison with the illustrationsof Liebau (1969,1971), Benson (1972,1977)
and Valicenti (1977), it follows that species in
the Trachyleberididae have similar reticulation patterns to those in the Hemicytheridae.
Thus, the number of epidermal cells is very
conservative even in different families. In
this way, each species has basically the same
number of epidermal cells, and the positioning of each cell seems to be genetically constrained (for example the A I cell is next to theA2 cell). However, each species has its own
ornamentation and valve shape because of thedifferent size, shape and arrangement of theepidermal cells.
b)Muscle scar patterns

Various muscle scars can be recognized on
the inner surface of ostracode valves. These
represent where the soft parts were attachedwith several muscles. There are three kindsof muscle scars: dorsal, frontal and adductor.

Their characteristics have been used for classifying families and genera and constructing
their phylogenetic trends. Hazel (1967) depicted the phylogenetic tree of some genera
belonging to both the Trachyleberididae andHemicytheridae on the basis of frontal andadductor muscle scar patterns. He put muchemphasis on the frontal scar patterns andconcluded that the time-successive development of three scars from two in the Hemicytherinae must be considered a phylomorphogenic trend. Similarly, he suggested that
there was a trend through time in the
Hemicytherinae toward the division of themedian adductor muscle scars. Schornikov(1974) investigated the muscle scar patterns ofsome Hemicythere species (H. emarginata, H.
nana Schornikov, and H. borealis (Brady».
The genus Hemicythere has usually been
considered to have two frontal scars, but
Schornikov (1974) found specimens having
both two and three frontal scars and various
numbers of adductor scars_ In the present
study, specimens having three frontal scars
were recognized in Hem icythere orientalis.
Doruk (1 974a, b, c) and Athersuch and Ruggieri (1975) also showed variations III

955.

Morphology of hemicytherin Ostracoda

Urocythereis species (U. favosa, U.
seminulum, U. labyrinthica, and U. phantastica, respectively) in the number of frontal
scars from two to three and in the division of
the four adductor scars. In this way,
hemicytherin ostracodes have considerable
variations in muscle scar patterns. However,there is a dominant pattern in each species.
Species having three frontal scars belong toPatagonacythere. Normanicythere.
Baffinicythere. and Finmarchinella (except
for F. rectangulata). In contrast, species
having two frontal scars are members ofJohnnealella. Urocythereis? Daishakacythere. and Hem icy there. and F. rectangulata.
The number of adductor muscle scars differs
even within the same genus: Daishakacythere abei has divided ventromedian scars but
D. posterocostata has an elongated one; andP. robusta has divided dorsal scars but P.
sasaokensis has an elongated one (Figure 138c). As pointed out by Doruk (1974a, b, c),
Athersuch and Ruggieri (1975), and Wouters(1979), even in the same species from a single
locality there are some variations: some ofthe specimens of Baffin icy there sp. 2 from
OK-I (Setana Formation) have divided dorsal scars and others an elongate one.
c)

Hingements

All the examined species have the same
holamphidont hingement except for thosebelonging to Finmarchinella (antimerodont)
although some variations are seen. For
example, Urocythereis had been considered tohave a stepped anterior hinge element, but
Doruk (l974a) showed that a single species
belonging to that genus has a stepped tosmooth anterior element.

Ontogenetic changes of pore
distributional patterns
Most ostracodes have two calcified valves(carapace) on which there are many pore
canal openings for bristles. These pores
have been dealt with by most ostracodologists
in bipartite fashion: normal pores distribut-

191

ed on the valve surface versus marginal pores
located along the valve margin; and simple
pores versus sieve pores. Hanai and Ikeya(1991), however, thought that normal pores
are the same as marginal pores in terms ofdevelopment; ostracode valves consist of asingle sheet layer (Kornicker, 1969) and theshape of pores is changeable in response to
the surrounding environments. They definedc- and v-types of pores. The former pertains
to pores which remain constant in positionand number through ontogeny, but the latteris variable in these aspects. Okada (1982b,
1983) compared pore morphologies on thevalve surface (normal pores) with those along
the valve margin (marginal pores) of Bicornucythere bisanensis (Okubo) and concluded
that they have very similar characteristics
although the length and position of pores arevariable. Even more significantly, the location of pores, or bristles, is geneticallycontrolled and constant in each species(Hanai, 1970; Rosenfeld, 1982; Tsukagoshi,1990). Bristles emanating from the valve
margin may be functionally different fromother pores distributed on the valve surface
based on their unique positioning. Thus,
investigated were the ontogenetic changes ofpores both on the valve surface and along theanterior valve margin, which hereafter are
called "marginal pores" only for the sake of
convenience. Marginal pores in the present
study are assigned to so-called radial pore
canals.
a)

Methods

To observe normal pore patterns, specimens soaked in water were observed by using
a transmitted light microscope, making reference to scanning electron micrographs. Previous observations were made on specimens
soaked in a glycerin water solution, which
was found to induce the specimens to break
down as they dried. Therefore, only waterinstead of glycerin was used in this study.
Hemicytherin ostracodes have so many poreson the valve in the adult stage (e.g., an adult
Baffin icy there sp. 1 has about 250 pores on

Toshiaki Irizuki

192

A

'.
B

C

D
E

D

F

G
H

J

Figure 4. Procedures for investigating ontogenetic changes of pores distributed along the anterior
valve margin. A to J represent the alphabetized fossa. Silhouettes of the valve are drawn after micrographs of the A-3 instar left valve of Finmarchinella nealei Okada. This specimen has II marginal pores.
Scale bars are 100 ,urn.

the valve surface) that it is difficult to recognize every pore if fossil specimens are poorly
preserved. Thus, examined in this study
were normal pore distributional patterns of
21 hemicytherin ostracodes in A-5 to A-3
instars to demonstrate intergeneric relationships among them. Marginal pores werestudied in left valves of A-3 to adult specimens. Table 1 shows the examined species
in A-5 to A-3 stages; the earliest stage is A-6of Baffinicythere sp. 2. Specimens immersed
in water on a glass slide were photographedusing a Nikon transmitted-light microscopeat 40 X and/or 80 X magnifications. Figure
4 summarizes procedures for the analyses.
Each fossa (reticulum) distributed along
the anterior valve margin was alphabetizedfrom A to 1. D and E cells are divided at an
ecdysis from A-4 to A-3 stages. Anterior
marginal pores were illustrated along the linefrom the anterior end of the hinge to the 1
mesh; the length of this line was standardized to facilitate a comparison of pore loca-

tions among specimens.
b) Ontogenetic changes of pores on the valve
surface

Studies of the distribution of pores on thevalve surface have been made by many
workers. The intraspecific stability of distributional patterns of pores has been recognized in various ostracode species (Hanai,
1970; Rosenfeld, 1982; Tsukagoshi, 1990).
Hence, these patterns can be used for classifying and relating the examined species. Plusquellec and Sandberg (1969) distinguishedsome consistent pore patterns, useful forphylogenetically relating species belonging to
the same genus. They also used differencesin pore patterns for separating similar genera.
Ha'nai (1970) observed little intraspecific variability in pore patterns and suggested thatspecies may be distinguished based on thesepatterns. Benson (1972, 1975, 1976) usedinterspecific differences in homologous porepatterns to display quantitatively differencesIn
valve morphology. Rosenfeld (1982)

955.

Morphology of hemicytherin Ostracoda

investigated pore distributional patterns of
two brackish-water species (Loxoconcha elliptica Brady and Cyprideis torosa (Jones»
and concluded that even in a brackish-water
environment subject to high stresses, theirpore patterns are stable and may be genetically controlled. Tsukagoshi (1990) showed
the phylogenetic scheme of species belonging
to the genus Cythere on the basis of
ontogenetic changes of pores distributed on
the valve surface. He indicated that all the
Cythere species have the same pore patterns
in the A-3 stage, and that interspecificdifferentiation in morphology occurs in later
growth stages, resulting in several species
groups. Up till now, ontogenetic changes ofpores in each species belonging to a single
genus have been examined, but changes in
species belonging to different allied genera
have not previously been investigated.
Figure 5 and Table I show the distributional patterns of pores on the valve
surface in A-5 to A-3 stages. The outlines of. the examined valves were drawn relative to
micrographs of Bafjinicythere sp. 2. For the
A-5 instar, specimens of only four species (B.
sp. 2, D. abei, F. hanaii, and N. japonica)
could be obtained for this analysis. Thesefour species have the same pore patterns(Table I and Figure 5). In the A-4 stage,
two groups are discernible: I)
B afjin icy there, Daishakacythere, Hemicythere emarginata, and H. orientalis, eachhaving pore D in common; 2) Finmarchinella, Hem icy there ochotensis, lohnnealella, Norma n icyth ere, Patagonacythere, andUrocythereis?, which have their inherent
pore E or E'. Thirty-nine pores are common
to all species in the A-3 stage (solid circles on
the A-3 instar valve in Figure 5), but tengroups are discernible on the basis of inherent
pores (Pores A to H' in Figure 5 and Table1). It is clearly shown that on the one handsome species within the same genus havedifferent pore patterns (e.g., species in thegenera Bafjinicythere, Finmarchinella,
Hem icyth ere, and Patagonacythere). On the

193

A-5

•

•

•

•
•

•

•

•
•

•

Figure 5. Ontogenetic changes of pores distributed on the valve surface. Solid circles represent
common pores in all species. A to I stand for pores
specific to certain species (see Table I). Silhouettesof specimens are drawn after micrographs of
B affin icy there sp. 2.

other hand, other species belonging todifferent genera have the same pore patterns
in the A-3 stage (e.g., two Bafjinicythere
species and three Daishakacythere species
have the same pores) (Table I).
c)

Ontogenetic changes of marginal pore patterns

The characteristics of marginal pores ofadult specimens were used for supragenericToshiaki Irizuki

194

Table 1. Species-specific normal pores in the A-5 to A-3 stages and the number of anterior marginal
pores (AMP) in the adult stage. Specimens shown by"/" could not be examined. Lettersrefer to cells where normal pores are observed in correspondence to Figure 5. Four species
in the A-5 stage have the same normal pore pattern (*). In the A-3 stage, ten groups are
discernible on the basis of inherent normal pores. All normal pores in A-3 instar juveniles
of Patagonacythere sasaokensis are common to the other examined species (P. sasaokensis
has no species-specific pores).

A-4

A-5

Baffin icyth ere

sp. I

B.
B.

sp. 2

/

A

A-3

F.

uranipponica

F.
F.

rectangulata

Hemicythere
H.
H.

subrectanglilata
emarginata
kitanipponica
orientalisH.

ochotensis
Johnnealella nopporoensis
Urocythereis ? gorokllensis
Normanicythere japonica
Patagonacythere
P.

Adult

ABCDEFGH

D~

sp.3
Daishakacythere abeiD.
posterocostataD.
sp. I
Finmarchinella hanaiiF.
japonicaF.
nealeiNo. ofAMP.

normal pores
specific to species

Species~-. - -- - - -_...... --- - - - - - -

~

~

-- --

82-83

*/

D
D

BC

*/

BC

FG
FG

61-63

D
D

BC

FG

60

D

BC

FG

/
/
/
/

/
/
/
/
/
/
/

robllsta*/sasaokensis/

taxonomy by Plusquellec and Sandberg(1969) and Liebau (1975). Plusquellec andSandberg (1969) suggested that the arrangement of marginal pores is of major importance to the study of speciation in the genus
Proteoconcha. However, ostracodologists
have not thoroughly studied ontogenetic
changes of marginal pores with the intentionof finding potential clues to the taxonomy of
ostracode genera and their phylogenetic reconstruction.

FG

69-72

-------------------.

E

~

BC

56-57

.. - -- - - - - -

BC
E

BC

H

40-43

E

BC

H

37-39

B

H

32-33

B

H

32-35
55-56

-------- ...... _---------------_.

/
E-- - - - - -- --_.. " " - - - -- - -- -. - - - - - ~

D

FG

/
B

D

F
E'
E
E
E'

C

E

/

/

H
H

/

*/

BC

39-40
42-43

C

FG
- - - - - - - -. FG I

C

H'

37-42

C

GH

40-42

C

GH

35-36

- -- -- - - - .... - - - - - - --

55-56

~.

-------- ... _.... _ .. _------------------- .... _----------------- ..

----------_ .... _----- .... _------

55-56

H'

31-33

H

34-35

---._---- .. _--_ .. _---._------- ..

33

It was impossible to group the examined
species by the morphology of marginal poresof the adult specimens, which all have straightpores slightly inflated in the middle part andsometimes fused. Their morphology is similar to that of Bicornucythere bisanensis studied by Okada (1982b). In general, there arefew variations in the number of marginal
pores in early juveniles, but intraspecific variations are recognized in the A-I and adultstages. Table I shows the number of mar-

955.

Morphology of hemicytherin Ostracoda

ginal pores of 20 species at the adult stage(adults of D. sp. I could not be obtained),demonstrating that they fall into two groups:
one has relatively numerous pores (55 - 83)
and the other has 31 to 43 pores. The former
includes Baffin icy there, Daishakacythere, andthe Hem icy there villosa group, and the latter
contains Finmarchinella, Hem icy there borealis group , Johnnealella, Norma n icy there,
Patagonacythere, and Uroc y thereis?
Schornikov (1974) divided Hem icy there into
two groups on the basis of ornamentation andvalve morphology , the H. villosa group(Hemicy there emarginata, H. orientaiis, andperhaps H. kitanipponica) and the H. borealis
group (H. ochotensis) . These two groups
also differ in the number of margin a l pores.
From the ontogenetic changes of marginal
pores, some groups can be discerned on the

19 5basis of the distributional patterns and thenumber. Figure 6 shows two examples ofthe ontogenetic changes of the anterior margina l pores of B affin icy there sp. I (Figures
6A -D) and Finmarchinella nealei (Figures
6E-H). Figure 7 indicates the ontogenetic
trajectories of the number of marginal poresshown by the 21 species.
A-5 juveniles of Baffin icy there sp.2, D.
abei, F. hanaii, N. japonica, and P. robusta
have the same number (4) and location of
marginal pores (8, DE, G, 1) (Figures 8, 9,
1 I).

At the A-4 stage, two types are manifested.
Species of the first type have seven marginal
pores and nearly the sa me pattern (A , DE, FI ,F2, G , H , J) (Figures6E, 9- 11). Thesebelong to such genera as Finmarchinella,
Hemicythere, Johnnealella, Norman icy there,

. C

(A-2)

.. (A-1)
D

Figure 6. Changes of anterior marginal pore patterns in B affin icy there sp. I (A-D) and Finmarchinella nealei (E-H). Numerals refer to the number of anterior marginal po res. A to J around the valve
margin represent the alphabetized fossa. Arrow heads show each anterior marginal pore. Scale bars are
100 tim.

Toshiaki Irizuki

196

.!Q
U)

c:

~U) ~.~
0 c:

~

~
:J
Ol

c:

~
U

~

~
~
:J
Ol

.!Q

c:

~
U

~

.Q

:J

U)

IJ..:

U)

C1l

c:

.S:

0

t1l

::::::

.l!!

C1l

.c:

c:
C1l
.c:
IJ..:

~

U

0

.~
c:
0

Q.

~

c:

c:
(J)

~

.9-

E
(J)

~

:t

:t

~

',=
0

:t

C1l

~
~

(J)

c:

E
0

'Q)

.~ .9-

u

(J)

Q.

.~
c:

.S2

0

E

Q.

2:0 Cij c:0
c:

U)

0

c::

.~

c:
~

:J

--; IJ..: IJ..: IJ..:

'Q)

.l!!
U)

.Q
C1l

0

Q.

ci..
(j)

ci

ci

ci

C\J

C')

ci..
(j)

ci..
(j)

ci..
(j)

CI:i

CI:i

CI:i

A-1

Figure 7. Ontogenetic trajectories ofthe examined species, as shown by patterns of marginal pores.
Numerals indicate the number of anterior marginal pore canals.

Patagonacythere and Urocythereis? Members of the second type are Daishakacythere
and Baffinicythere, each of which has morethan ten marginal pores. The number andlocation of marginal pores are generally characteristic of species belonging to each genus:
Baffin icythere has 11 marginal pores (Figure6A) and Daishakacythere ten marginal pores(Figure 8).
The detailed ontogenetic trajectories ofmarginal pores in each genus are as follows.
Baffin icy there

Three species of Baffinicythere (B. sp. 1,2,

3) have the same marginal pore patterns in the
A-4 and A-3 stages (Figures 6A-D, 7). These
will be considered in detail in another paper.
Daishakacythere

In this study, three species belonging to
Daishakacythere were recognized, D. abei, D.
posterocostata, and D. sp. 1 ; adult specimensof the last could not be found. At the A-4stage these three species have the same marginal pore patterns mentioned above. In the
A-3 stage, both D. posterocostata and D. sp. 1
have 14 marginal pores in the same arrangement, whereas most specimens of D. abei have

955.

Morphology of hemicytherin Ostracoda

A-3
D. posterocostata•

D. sp. 1

rB

C

A-S
A

r-

B

F
G
H

B
r-

A

B

B

•

D

D

E

E

F

F

F

~

;G

G

H

H

D
E

G

I

;;;;:J
14

-

• •
A

A

•

B

B

B

B

c

C

C

D

D

~

F

F

G

G

H

H
I
J

1

I
10

I

~

-..

C
D
E
rF
r-

F
H
b J

•

B

•

E

30

A

A

D

E

•

H

A-1

A

E

F

rH

C

C

r-

I
4

A

E

~

•, • •

A

C
Q
E

D

A-4

•

A-2

•'A •

.& D. abei
•

197

41

A

A

B

B

C
39

•

D

G

li

rr

I-'-

d

13

24

39

Figure 8. Ontogenetic changes of anterior marginal pores of Daishakacythere on the basis of suchdiagrams as shown in Figure 6. A to J stand for the alphabetized anterior marginal fossa in Figures 5 and6. Small arrow heads (~ ) show the location where some specimens have inset pores. Numerals indicate
the number of anterior marginal pore canals. Each species in a frame has the same distributional patternof anterior marginal pores.

smaller numbers of marginal pores due to aloss of one in the C cell (in the Shibikawa
Formation, 10 percent of the individuals havea marginal pore in the C cell). Also in the
A-2 stage, D. posterocostata and D. sp. I havethe same pattern. The three species at theA-I stage have their own patterns (Figure 8).
Finmarchinella

The genus Finmarchinella was establishedby Swain (1963). In addition, Neale (1974)
created two subgenera: Finmarchinella (Finmarchinella) and Finmarchinella (Barent-

sovia). Species of the subgenus Barentsovia
have conspicuous subcentral tubercles, whereas those of the subgenus Finmarchinella do
not have such prominent ones. Such a distinction is, however, inconsistent even within
a single species: specimens of Finmarchinella
nealei from the Shibikawa Formation havesubcentral tubercles, while those from the
Sasaoka Formation have no conspicuous
tubercles. Thus, it is difficult in reality toassign species to one or the other. In thisstudy, the rank of subgenus is not used.

Toshiaki Irizuki

198

two groups are manifested in the A-3 stage:
9-marginal-pore and II-marginal-pore types.
Each of these types includes three species:
the 9-pore type includes F. hanaii, F. rectangulata, and F. subrectangulata (8, C, D, E, F,
G, H, I, J), and the II-pore type F. japonica,
F. nealei, and F. uranipponica (8, C, D, E I,
E2, F, GI, G2, H, I, J). Finmarchinellajaponica and F. nealei have the same patterns
in the A-4 to A-I stages, but F. uranipponica
has a slightly different pattern in the A-2 andA-I stages. In the A-2 stage, F. hanaii andNine Finmarchinella species have been described from Japan, but only six species (F.
hanaii, F. japonica, F. nealei, F. rectangulata,
F. subrectangulata sp. nov., and F.
uranipponica) were examined in this study,
because A-3 specimens of three species (F.
daishakaensis Tabuki, F. sp. of Tabuki(1986), and F. ? sp. of Tabuki (1986)) could
not be obtained. These five species (except
for F. rectangulata, for which A-4 specimens
could not be obtained) have the same A-4
marginal pore patterns mentioned above, but

A-3• F. hanaii'" F. japonica

A-S•

F. nealei•

F. rectangulata•

F. subrectangulata•

F. uranipponica

•
.-A

B

e
D
E
Flo+-

H
II

L4

~

A

A

B

e

e

D

D

E

E

r-

D
E
F
G

A

B

B

B

e

e

e

e

D
E

D
E

D
E

D
E

F

F

F

F

H

~

~
L-

I

L-7

G
H

f-

I

L-

I•

G
H

f-

I

L-

~

H
I
J

...

F

I

~~

~
~

F

A

~

Il

~

e

B

Is

i;

B

IB

D

e

e

e

~

E
F

IE I-

E
F

~

I

I

J

26

19

J

•

B

I-B

e

e

D

D

E

E

F

F

G
H
I
J

G

F

H
I
J

G
H
I
rJ

~

~~

r-A

A

B

B

A

I-

B

~

D
E

15,

---

I

•

A

IU

E

E I-

F

F

co

t:i

H

H

I

I
I..

17

J

F

~

H
I

I

J

p,J
29

.--r-

r-.--

D

J

E

,~

e

e

D

=F
t- I
rt-J

A

9

F

~

A

~

E

H

--.

• t~

E
F

tJ

1

r-

•

~

,.....,

H

G IH
I
J

A-1
~

A

B

e

A

G

r~

r-

A

B

jA

G

•

B

r!t •.-- •
t-A

•

B

A-4

G
f-

•

A-2

I

Is
e
D
E
F
IG
H

Vr-~

t:::i.....

IA

IE

e

A
IB

e

D
E
F

:Q
H
I
J
24

E
F

~H
I
J

22

22

Figure 9. Ontogenetic changes of anterior marginal pores of Finmarchinella.
same as in Figure 8.

Abbreviations are the955.

Morphology of hemicytherin Ostracoda

F. subrectangulata of the 9-pore type havealmost the same patterns and F. rectangulata
has two fewer marginal pores than do theother two species (Figure 9).
Hem icy there

Schornikov (1974) described many
Hemicythere species from the Kurile Islands.
In A-3 and A-4 stages, all these Hemicythere
species have almost the same pattern (ninemarginal pores in the A-3 stage (B, C, D, E, F,
At the A-2 stage, two groups are
G, H, I,
recognized: 22 (21 )-pore and l7-pore types.
The former contains H. emarginata, H.

J».

kitanipponica, and H. orientalis, all of which
also have patterns similar to each other at the
A- I stage (35 or 36 marginal pores). The
latter type is shown by H. ochotensis, having
fewer marginal pores at the A-I stage (only 24
marginal pores). In addition, Schornikov's(1974) illustrations of the H. villosa and H.
borealis groups show that the former has moremarginal pores than the latter (Figure 10).
Johnnea/el/a, Normanicythere,
and Urocythereis?

A H. emarginata
H. kitanipponica•

H. ochotensis•

H. orienta/is

. ••

•
A

B

IA

IA riA

113

B

•
A

B

C
0
E

F

E

E

F

F

k;

0
E

F

I"

H

H

H

I

I

I
7

H
I

.. • •

A-3

A-4

•

IA

~

B

C

~

C

0

0
E

0
E

F

F

G

~

H

H

I
J

I
J

...

E
~

B

B

E
F

F

H
I

J

A-1

••

F
ICJ

j{i

0 _
1
E

21

I
I I=J
L..
J
2

F
G

Patagonacythere,

Patagonacythere and Urocythereis havebeen considered to belong to the tribe

A-2
•

199

•

It,;

r-

IA

H

•

Ie

I
J

II'

9

-"

lu
E
F
G

H
I
J
17

Figure 10. Ontogenetic changes of anterior marginal pores of Hem icythere.
same as in Figure 8.

24Abbreviations are theToshiaki Jrizuki

200

Patagonacythere and Norman icy there in the
A-4 to A-2 stages, but at the A-I stage, it has
one more marginal pore than do the otherthree species. A-3 juveniles of J. nopporoensis generally have ten marginal pores (onemore marginal pore in the F cell), but somehave nine marginal pores as in the other four
species. In the A-2 stage, it has three moremarginal pores than do the others (Figure
II ).

Urocythereidini. In the meantime, Normanicythere japonica was described by Tabuki (1986). Johnnealella, established by
Hanai and Ikeya (1991), has a similar morphology to Urocythereis? gorokuensis andis monotypic at present. Ontogenetic patterns of these four genera were examined.
Patagonacythere robusta and N. japonica
have the same marginal pore patterns in the
A-5 to A-I stages; Patagonacythere sasaokensis also has this pattern in the stages
examined (A-3 to A-I). Urocythereis?
gorokuensis has the same pattern as

•
•
•
•

•

J. nopporoensis

A-4

N.japonica

P. robusta

••

r-r-

A

•

B

B

.--

r-

P. sasaokensis
U. ? gorokuensis

A

B

e

e

A-5

D

D

••

E

E
F

A

B

e
D

E

IU
E

F

F

IG

~

H

H

I
4

....

H

A

•

~
rA
IB

I-

A

l-

e e
D

E

F

F

G

G

H

•IA

A-3

H
I

~

I-

D
l-

E

l-

F

F

I-

G

G

rH
rI
r-

7

A

B

B

B

lr-

e

e

e

In
E

D

D

10

E

E

E
F

F

G
H
I

L-

F

G

G

H

H
I

J

~

F

D

D

E

E

E ---..

E

F
(j
H

F
(j

F

F

G

H

H

I

I

J 110

•

B

e

I

J

•

~H

~

B

I

J

J

~

1~

•
A

B

e
D

E
F
~

G

~

H
I

J
18

I
J

E

•

F

r-r-

~

B

B

I

J

G
H

I-

l-

e

A

B

t--t--

~

D

9

A

IA

-~

~

e

r-r-

A

IA

r-

B

J

J

r-r-

A-1

B

.....
•
!.!.
• •
J

r-r-

A

H
I

•

• •

~

r-

IA

H
I

B

J
23

•
I-

~

H
I

I-

-

=~
25

Figure 11. Ontogenetic changes of anterior marginal pores of lohnnealella, Normanicythere,
Patagonacythere, and Urocythereis? Abbreviations are the same as in Figure 8.

955.

Morphology of hemicytherin Ostracoda

Discussion
The taxonomy of fossil ostracodes is basedby paleontologists on the characteristics ofthe carapaces, whereas living ones are studied
by using features both of the carapace morphology and soft tissues (e.g., sexual organs,appendages, etc.); classifications based only
on the valve morphology are sometimes
different from those derived from study of thesoft tissues. However, various features ofreticulation and pores on the ostracode carapace are direct reflections of the arrangementof underlying epidermal cells and nerve or
secretory cells, respectively. Muscle scars
express attachments for soft tissues. Therefore, we can classify fossil ostracodes using
characters of biologic significance. Genera
first described as fossils are defined on thebasis of carapace morphology: prominentornamentation, hingements, and musle scarpatterns. Reticulation patterns based on
Liebau's (1969) system are the same in all theexamined species. Hence, this method canbe of no help for species division, but may be
useful for defining homologous fossae among
species.
Hemicytherin ostracodes are very conservative with respect to the distribution and orderof division of reticulation because Eocene
species of Patagonacythere illustrated by
Valicenti (1977) have very similar reticulation
patterns to those of the late Miocene to Pleistocene species (P. robusta and P. sasaokensis). Frontal muscle scar patterns may be ofsome help for generic classification with some
exceptions. However, as shown by Hazel's(1967) phylogenetic tree, similar frontal muscle scar patterns are shared among different
branches (analogy); in view of the pore patterns mentioned later, it is questionable
whether species having the same frontal muscle patterns are related to each other. Large
variations in adductor muscle scar patterns
are shown even among species in the same
genus. Thus, these characters may be of nouse in generic taxonomy. Ontogenetic

201

changes of the distributional patterns of anterior marginal pores examined first in thepresent study provide useful information for
taxonomy and phylogeny.
Species which have been assigned to asingle genus by previous workers follow similar ontogenetic trajectories with the exceptionof "Urocythereis". Species belonging toPatagonacythere, Norman icy there, or F.
rectangulata have almost the same
ontogenetic trajectories (4-7-9-15-22-33 inpore number). Other Finmarchinr;lla
species, Johnnealella, and Urocythereis?
have smaller numbers of marginal pores( u.? gorokuensis has the same trajectory up
to the A-2 stage as Patagonacythere). Therefore, these genera are thought to be related toeach other. With regard to pores distributedon the valve surface, Finmarchinella, Johnnealella and Urocythereis? develop the H
or H' pore at the A-3 stage, as do Normanicythere and Patagonacythere robusta.
This supports the above inference based on
the results of ontogenetic trajectories of anterior marginal pores. Species in the
Hem icy there villosa group (H. emarginata, H.
kitanipponica, and H. orientalis) have fewer
pores at early instars, but in the A-2 to adultstages, they have more marginal pores thanthose in the Patagonacythere group. They
do not have the H pore, but have similar
pores to species of the Baffinicythere group.
Hemicythere ochotensis differs from the
Hem icythere villosa group in both marginaland valve surface pores. The carapace morphology of H. ochotensis also differs fromthat of the H. villosa group. The former has
quadrate and large valves, whereas the latterhas subtriangular valves. Thus, they may be
divided into two subgenera or genera in the
future.
Of the examined genera, Patagonacythere
has the oldest fossil records, which extend as
far back as the Eocene in Patagonia(Valicenti, 1977). In Japan, no ostracodes
have been investigated for the Paleogene toearly Miocene, but Yaj ima (1988) reported

Toshiaki Irizuki

202

Cornucoquimba saUoi from the early middle
Miocene. It is actually identical with Ambostracon sp. 2 of Tabuki (1986) and should
eventually be assigned to Patagonacythere.
Similarly, Finmarchinella hanaii was recognized from the early middle Miocene Togi
Formation, central Japan (Yajima, 1988).
Therefore, it may be that Finmarchinella
species were descended from thePatagonacythere group (Urocythereidini).
With respect to marginal pores, Baffinicythere
and Daishakacythere correspond to thePatagonacythere group at the A-5 stage, butdiffer in their subsequent juvenile and adultstages. In this way, D. abei and D. posterocostata, which have been considered comparable to a genus related to Urocythereis?
gorokuensis, should be placed in a genus
different from u.? gorokuensis. In thisstudy, a new genus, Daishakacythere, is
proposed to incl ude u.? abei and U.? posterocostata. In the A-3 instars, B. sp. 2, B.
sp. 3 and three species of Daishakacythere
have the same normal pores, suggesting thatthese species are descended from a common
ancestor (Table I). Daishakacythere andB affin icy there are also very similar in their
marginal pores: A-4 instar juveniles of Daishakacythere have one less marginal pore in
the DE cell than those of Baffinicythere, andA-3 juveniles of D. posterocostata and D.
sp. 1 have one less pore in the G cell thanthose of Baffin icy there (Figures 6 and 8).
Hemicythere emarginata was placed underBaffin icy there (Hazel, 1967), but the resultsfrom the above analyses support Schornikov(1974) and Horne and Whittaker (1983) in theview that emarginata should remain in
Hem icy there.

among species, not only in the Hemicytherinae but also among its related subfamilies.
2. Ontogenetic changes of the distributional patterns of pores on the valve
surface appear to be a good guide to theelucidation of interspecific relationships, but
A-3 instar juveniles of some species havedifferent pore patterns even within the same
genus.
3. Ontogenetic changes of marginal poresprovide a good clue to the taxonomy of
ostracode genera and their phylogenetic reconstruction.
4. On the basis of marginal pores,
Patagonacythere, Norman icy there, Johnnealella, Urocythereis?, and Finmarchinella
are related to each other; B affin icy there andDaishakacythere together form anothergroup.
5. The Hem icy there vil/osa group differsfrom the Hemicythere borealis group in bothmarginal pores and normal pores. Thus, thesimilarity of their valve morphology may
have resulted from convergence.

Systematic descriptions
All the illustrated and measured specimens
are deposited in the collections of the Institute of Geology and Paleontology, Faculty of
Science, Tohoku University (lGPS). Sample
localities are listed in Table 2. In this section, one new genus and two new species aredescribed, and brief comments are made on
three species.

Conclusions

Suborder Podocopina Sars, 1866
Superfamily Cytheracea Baird, 1850
Family Hemicytheridae Puri, 1953
Subfamily Hemicytherinae Puri, 1953
Genus Daishakacythere, gen. nov.

The following conclusions are drawn fromthe study of morphological relationships
among hemicytherin genera:
1. Distributional patterns of reticulationand c-type pore canals are very conservative

Type species.- Urocythereis? abei Tabuki, 1986
Etymology.-After the name of formationfrom which the type specimen was collected.
Diagnosis.-A genus characterized by retic-

955,
Table 2,Morphology of hemicytherin Ostracoda

203

Localities of the examined specimens. Numerals in parentheses refer to those in Figure I. Abbrevi.
ations V., T., C., and P. in "Region" stand for Village, Town, City, and Prefecture, respectively.
Detailed locations of samples from the Sasaoka and Tentokuji Formations, Otsuchi Bay, and Toyama
Bay are described in Irizuki (1989), Fujioka el al. (1988), and Katayama (1989), respectively.

No.
SampleLatitude
RECENT(I)
STA·I
4S"I3.I'N(3)
FI2
42"6.6'N(12)
ST. 3139'22'10"'N
(13)
03702
37'33.41 'N
(13)
03705
37·32.40'N
(13)
03768
37·28.76'N
(13)
03794
37"26.34'N
(13)
03771
3T20.04'N
(13)
03631
37"14.78'N
(13)
03775
37'09.SI'N
(13)
03629
37"04.87'N
MIDDLE TO UPPER PLEISTOCENE
( 8 )
523-4
39'S8'08"'N
( 9 )
523-6
39"S8'07"N
( 9 )
523-9
39'S8'06"'N
LOWER PLEISTOCENE(4)
CHI·1341"11'14"'N
(4)
CHI·9
41"11'08"'N
(4)
CHI·6
4I'II'03"'N
(4)
MAE·4
41"1O'26"'N
(4)
MAE·3
4I'IO'2S"'N
(14)
L, 32
36'31'4S"'N
(14)
L,31
36'31'4S"'N
(14)
L, 30
36'31'4S"'N
(14)
L, 29
36'31 '4S"'N
(14)
L,20
36'31'43"'N
(14)
L,13
36'31'42"'N
(14)
No.66
36'31'36"'N(14)
No. 6536'31'36"'N(14)
No. 4336'31'34"'N
(14)
R.20
36'31'34"'N(14)
No. 2636'31'34"'N
(14)
R.14
36'31'34"'N
PLlO·PLEISTOCENE(2)
OK·I
42'20'17"N(2)
OK·2
42'20' 17"N
(2)
PSK·S
42'19'16"N
(2)
PSK·6
42'19'16"N
(2)
PSK·7
42'19'IS"N
( 2 )
SK·3
42'18'41"N(2)
SK·I
42'18'40"N
( 5 )
914-5
40'4S'12"N
(5)
914-6
40'4S'12"N
(5)
916-7
40'42'46"N
(5)
916-8
40'42'46"NUPPER PLIOCENE
(10)
524-8
39'S6'00"N
(10)
MON·2
39'55'07" N(10)
HAT·IS
39'4S'SS"N
39'4S'S4"N(10)
HAT·7S
39'4S'S4"N(10)
HAT·6S(10)
HAT·4S
39'4S'S3"N
39'4S'S3"N(10)
HAT·3S
39'4S'S3"N(10)
HAT·2S
39'4S'S2"N(10)
HAT·SS
39'4S'13"N(10)
KOS·IS(10)
KOS·2S
39'45'11 "N(10)
KOS·3S
39'4S'09"N(10)
HIR·IS
39'44'36"N
39'44'33"N(10)
HIR·2S(10)
SUN·IS
39'44'26"N(10)
HIR·3S
39'44'2S"N(10)
HIR·4S
39'44'2S"N
39'44'2S"N(10)
HIR-SS
39'44'02"'N(10)
SAR·IS(10)
TAI·3S
39'44'00"'N(10)
TAI·2S
39'43'S9"N(10)
TAI·IS
39'43'47"N(II)
TAI·9T
39'43'40"N(II)
KAI-IT
39'43'30"N
UPPER MIOCENE
(6)
STZ·3
40'20'20"N
40'20'19"N
(6)
STZ·2
40'03'20"N
(7)
FC·II
(7)
FC·IS
40'02'3S"N
(7)
FC·14
40'02'30"N
40'02'28"N
(7)
FC·13
40'02'27"N
(7)
FC·12

Longitude

Locality142'46.I'E
140"48.3'E
I 42"00'[Xl"E
I 36"S2.22'E
137"0I.SI'E
137"24.84' E
13T28.94'E
13TI8.26'E
I 36"37.S6'E
137"07.16'E
136" 39.61' E

off Hamatonbetsu
Funka Bay
Otsuchi Bay
Toyama Bay
Toyama Bay
Toyama Bay
Toyama Bay
Toyama Bay
Toyama Bay
Toyama Bay
Toyama Bay

139"SI'OI"'E
I 39'SO'S8"'E
I 39"SO'S6"'E

Andcn F.
Shibikawa F.
Shibikuwa F.

141"17'16"'E
141"I7'02"'E
141"16'4S"'E
141"16'48"'E
141"16'47"E
136"41 '04"'E
I 36'41'04"'E
136'41 '04"' E
136'4 I '04"'E
136'41'OS"'E
I 36"41'OS"'E
136'41' IO"'E
136"41'IO"'E
136'41' 10"'E
136'41'IS"'E
136"41'II"'E
136"41' IS"' E

Hamada F.
Hamada F.
Hamada F.
Hamada F.
Hamada F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.
Omma F.

Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawu P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.
Kanazawa C., Ishikawa P.

140'17'OO"E
140"17'00" E
140'08'I3"E
140"18'IS"E140'08'IS"E140'08'03" E
140"38'3S"E
140'38'3S"E140" 38' 30" E
140' 38' 30" E

Sctana F.
Sctana F.
Sctana F.
Sctana F.
Setana F.
Selana F.
Setana F.
Daishaka F.
Daishaka F.
Daishaka F.
Daishaka F.

Yakumo T., Hokkaido
Yakumo T., Hokkaido
Yakumo T .. Hokkaido
Yakumo T., Hokkaido
Yakumo T., Hokkaido
Yakumo T., Hokkaido
Yakumo T., Hokkaido
Aomori C., Aomori P.
Aomori C., Aomori P.
Namioka T., Aomori P.
Namioka T., Aomori P.

140"1O'10"E140' 10'03" E
140·13'OS"E
140··12'SS"E
140··12'SS"E
140··13'00" E
14[rt3'02"E
140··13'OS"E
140··12'S9"E
140··13'2S"E
140'13'26"E
140"\3'22"E
140'14'OS"E
140"14'03"'E
140'14'28"E
140'13'S9"'E
140' \3' 59" E
140" 13'S9"E
140'IS'OS"E
140'14'II"E
140'14'40"E
140'14'SS"E
140"16'16"E
140'16'09"E

Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Sasaoka F.
Tcntokuji F.
Tentokuji F.

Gojonomc T., Akita P.
Gojonome T., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita c., Akita P.
Akita C .. Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita c., Akita P.
Akita c., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita c., Akita P.
Akita c., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita C., Akita P.
Akita c., Akita P.

141'15' 35" E

Shitazaki F.
Shitazaki F.
Fujikotogawa F.
Fujikotogawa F.
Fujikotogawa F.
Fujikotogawa F.
Fujikotogawa F.

Ninohc C., Iwate P.
Ninohc C., Iwate P.
Kamikoani V., Akita P.
Kamikoani V., Akita P.
Kamikoani V., Akita P.
Kamikoani V., Akita P.
Kamikoani V., Akita P.

140'07' 59" E

14I'IS'33"E
140"21'49"E
140'22'42"E
140"22'40"E
140··22'38"E
140'22'3S"ERegion(depth= 106 m)(depth=40 m)(depth=82 m)(depth= 102 m)(depth = 89 m)(depth=83 m)(depth = 147 m)(depth = 70 m)(depth=71 m)(depth = 78 m)(depth-61 m)
Oga c., Akita P.
Oga c., Akita P.
Oga C., Akita P.

Mutsu C., Aomori P.
Mutsu C .. Aomori P.
Mutsu C., Aomori P.

Mutsu C., Aomori P.
Mutsu C., Aomori P.

204

Toshiaki Irizuki

ulation over the whole carapace, two frontal
scars, and many pores distributed along marginal area. This genus contains three
species: Daishakacythere abei (Tabuki,1986), D. posterocostata (Tabuki, 1986), andD. sp. I. This is a representative Pleistocene
cryophilic genus in northern Japan.
Description.-Carapace very large, subtrapezoidal, slightly tapering posteriorly, highest
at anterior cardinal angle. Dorsal margin
nearly straight or slightly sinuous. Ventral
margin gently arched. Anterior margi n
broadly rounded, slightly extended below.
Posterior margin slightly concave in its upper
half and convex in its lower half, andacuminate. Subcentral tubercle rather
obscure. Eye tubercle low but prominent.
Coarse reticulation covers entire surface, but
obscure in younger instars, when carapace
slightly auriform. Radiating ridges recognizable both in anterior and posterior portions.
Sinuate ventral ridge prominent. Marginal
infold narrow along entire margin. Hinge
holamphidont. Muscle scars consisting of
two rounded frontal scars and a row of four
adductor scars: an elongated dorsal scar, tworounded dorsomedian scars, two roundedscars (D. abei) or an elongated scar (D. posterocostata and D. sp. 1) ventromedially, andan elongated ventral scar. Sexual dimorphism marked: males more elongated thanfemales.
Remarks.- Two species belonging to thisgenus (D. abei and D. posterocostata) havebeen described under the genus Urocythereis? Daishakacythere is, however, different
from Urocythereis? in having many pores
along the carapace margin and in being auri-form in juvenile stages. Ontogenetic changesof pore distribution (normal and marginal)suggest that this genus is related to the genus
Baffin icy there despite different numbers offrontal scars.

Daishakacythere abei (Tabuki, 1986)
Figures 1-4, 12-1-4b

Urocythereis gorokuensis Ishizaki; Ishizaki andMatoba, 1985, pl. 6, figs. II, 13 (non Urocythereis
gorokuensis Ishizaki, 1966, p. 144, 145, pl. 19,
figs. 9, 10, text-fig. I, fig. 7).
Urocythereis? abei Tabuki, 1986, p.71-73, pl. 6,
figs. I-II, pl. 20, fig. 5, text-fig. 18-6.

Dimensions.-Fig.12-1, male LV, Loc.
523-6,IGPS 101653, L= 1.205 mm, H=0.625mm; Figs. 12-2a-b, female LV, Loc. 523-6,
IGPS 101654, L= 1.106 mm, H=0.640 mm;
Figs. 2-4, 12-3, male RV, Loc. 523-6, IGPS
101655, L= 1.269 mm, H=0.609 mm; Figs.
12-4a-b, female RV, Loc. 523-6, IGPS
101656, L= 1.129 mm, H=0.630 mm.
Occurrence.-Dominant in the Shibikawa
Formation. Common in the Setana,
Hamada, Daishaka, and Anden Formations.
Remarks: This species resembles Daishakacythere sp. I in its overall shape and ornamentation, but differs in having the posteroventral ridge and two divided ventromedianscars.
Daishakacythere posterocostata(Tabuki, 1986)
Figures 2-5, 12-5a-8

Urocythereis? posterocostata Tabuki, 1986, p.73,
74, pl. 8, figs. 1-10, text-fig. 18-7.
not "Urocythereis" posterocaudata Cronin and Ikeya,~
Figure 12. 1-4, Daishakacythere abei (Tabuki, 1986), gen. nov. 1: lateral view of male LV, Loc.
523-6, IGPS 101653; 2a-b: internal and lateral views of female LV, Loc. 523-6, IGPS 101654; 3: lateralview of male RV, Loc. 523-6, IGPS 101655; 4a-b: internal and lateral views of female right valve, Loc. 5236, IGPS 101656. 5-8, Daishakacythere posterocostata (Tabuki, 1986), gen. nov. 5a-b: lateral and internalviews of male LV, Loc. MAE-3, IGPS 101662; 6: lateral view of female LV, Loc. MAE-3, IGPS 101663 ;7a-b: lateral and internal views of male RV, Loc. MAE-3, IGPS 101664; 8: lateral view offemale RV, Loc.
MAE-3, IGPS 101665. 9-12, Daishakacythere sp. 1, gen. nov. 9: lateral view of A-I stage LV, Loc. CHI-9,
IGPS 101672; 10a-b: internal and lateral views of A-I stage RV, Loc. MAE-3, IGPS 101673; 11: lateralview of A-2 stage LV, Loc. CHI-9, IGPS 101674; 12: lateral view of A-2 stage RV, Loc. CHI-9, IGPS
101675. Scale bars are 0.5 mm: A for 1-8; B for II, 12.

955.

Morphology of hemicYlherin Ostracoda

205

Toshiaki Irizuki

206

1987, p. 82, pI. 1, fig. 18.

Dimensions.-Figs. 12-5a-b, male LV,
Loc. MAE-3, IGPS 101662, L=1.l13mm,
H =0.57 mm; Fig. 12-6, female LV, Loc.
MAE-3, IGPS 101663, L= 1.069 mm, H=
0.613 mm; Figs. 2-5, 12-7a-b, male RV,
Loc. MAE-3, IGPS 101664, L= 1.188 mm,
H=0.584mm; Fig. 12-8, female RV, Loc.
MAE-3, IGPS 101665, L= 1.081 mm, H=0.60
mm.
Occurrence.-Common in the Setana,
Hamada and Daishaka Formations; rare in
the Shibikawa Formation.
Remarks.- This species resembles Daishakacythere abei in its overall shape and ornamentation, but differs in having posteroventral and posterodorsal rims.
Daishakacythere sp. 1
Figures 2-6, 12-9-12

Diagnosis. - Daishakacythere characterized
by lack of posterior rims in juveniles.
Dimensions.-Fig.12-9, A-I instar LV,
Loc. CHI-9, IGPS 101672, L=0.815 mm, H=
0.468mm; Figs. 2-6, 12-lOa-b, A-I instar
RV, Loc. MAE-3, IGPS 101673, L=0.820
mm, H=0.400mm;Fig.12-11, A-2 instar
LV, Loc. CHI-9, IGPS 101674, L=0.643 mm,
H=0.378 mm; Fig. 12-12, A-2 instar RV,
Loc. CHI-9, IGPS 101675, L=0.659 mm, H=
0.393 mm.
Occurrence.- The Setana, Hamada, andDaishaka Formations.
Remarks.-Adult specimens of this species
could not be found in the examined samples.
Juvenile valves are similar to Norm an icythere
japonica Tabuki, 1986, but the latter hasposterior denticles and fewer pores along thevalve margin.
Genus Finmarchinella Swain, 1963
Finmarchinella subrectangulata
sp. nov.
Figures 2-11, 13-1-4c

Etymology.-After valve shape.
Diagnosis. - Finmarchinella characterized
by subrectangular valve shape, posteroventral
ridge, two ovate and one small frontal scars
and overall microreticulation.
Description.-Carapace small in male andmoderate in female, thin, elongate, subrectangular in lateral view, highest at anterior cardinal angle. Dorsal margin straight. Ventral
margin sinuous; concave in anterior third.
Anterior margin broadly and evenly rounded.
Posterior margin concave in its upper half,
meeting dorsal margin at an obtuse angle, andlower half protruding into a caudal process.
As viewed dorsally, subcentral and eye tubercles obscure. Surface ornamented with finereticulation. Prominent ventral ridge, starting in anteroventral area, curv'ing upward atabout posterior one-fifth of valve length, terminating at the tip of caudal process. "{'woweak ridges radially extending from subcentral tubercle to anterior margin. Pores
scattered on valve surface moderate in number. Marginal pores moderate in number
along anteroventral margin. Marginal
infold moderate in width along anterior
margin, but narrow along ventral margin.
Line of concrescence coincident with inner
margin. Hinge antimerodont. Muscle scars
consist of three frontal scars, of which middle
scar is smaller, and an oblique row of four
adductor scars: an elongated dorsal scar, twoelongated dorsomedian scars, imperfectly
divided and elongated ventromedian scars
and one ventral scar. Sexual dimorphisrr:
remarkable: males smaller and more elongate than females.
Types and Dimensions.-Holotype:female LV, Loc. 523-6, IGPS 101739, Figs 132a-b, L=0.639 mm, H=0.306 mm; paratypes: male LV, Loc. 523-6, IGPS 101738,
Fig. 13-1, L = 0.526 mm, H = 0.244 mm ;female RV, Loc. 523-6, IGPS 101741, Figs.
13-4a -c, L = 0.638 mm, H = 0.294 mm; male
RV, Loc. 523-6, IGPS 101740, Figs. 2-11,133, L = 0.498 mm, H = 0.230 mm.
Type locality.-Middle Pleistocene Shibik-

955.

Morphology of hemicytherin Ostracoda

Figure 13. 1- 4, Finmarchinella subrectangulata sp. nov. , 1: lateral view of male LV , paratype, Loc.
523-6, IGPS 101738 ; 2a-b : internal and lateral views of female LV, holotype, Loc. 523 - 6, IGPS 101739 ;3: lateral view of male RV , paratype, Loc. 523- 6, IG PS 101740; 4a-c: internal and lateral views andmuscle scars of female RV , paratype, Loc. 523-6, IGPS 101741. 5- 8, Patagonacythere sasaokensis sp. nov. ,5: lateral view of male LV , paratype, Loc. HIR-3S, IG PS 101821 ; 6a-b, intern al and latera l views offemale LV , paratype, Loc. SUN-IS, IGPS 101822 ; 7 : lateral view of male RV , paratype, Loc. HIR-3S,
IGPS 101823; 8a-c: internal and latera l views and muscle scars of female RV , holotype, Loc. HIR-5S,
IGPS 101 824. Scale bars A and Bare 0.5 mm and C and Dare 0.1 mm: A for 1- 4b ; B for 5- 8b; C for
4c ; D for 8c.

207Toshiaki Irizuki

208

awa Formation, Loc. 523-6
Occurrence.-Common in the Shibikawa
Formations; rare in the Daishaka and
Hamada Formations.
Remarks.- This species is similar, possibly
related, to Finmarchinella? sp. of Tabuki(1986), but differs in having a posteroventral
ridge. It differs from Finmarchinella rectangulata Tabuki in having no posterodorsal
projection and a more elongated carapace.
It is also similar to Fin march in ella finmarchica, but differs in having elongated valvesand caudal processes.
Genus Patagonacythere Hartmann, 1962
Patagonacythere sasaokensis, sp. nov.
Figures 2-21, 13-5-8c

Etymology.-After the name of formation
which yielded the type specimen of thisspecies.
Diagnosis.- Patagonacythere charcterized
by anterior ridge and overall reticulation.
Description.-Carapace large, subrectangular in lateral view, highest at anterior cardinal angle. Anterior margin broadly rounded
and slightly extended below. Dorsal margin
straight. Ventral margin slightly sinuate.
Posterior margin rounded in LV, but triangular in RV; upper half concave but lower halfrounded. Surface ornamented entirely bycoarse reticulations. An anterior marginal
ridge distinct. Ventral ridge relatively
strong, starting at anterior marginal ridge
toward mid-ventral margin, then turning
toward posteroventral area. A narrow posterior marginal ridge 'starting just before posterior cardinal angle to inside acumination.
Subcentral tubercle low but distinct in adultstage. Eye tubercle not prominent. Pores
scattered on valve surface moderate in number. Marginal pores nearly straight, moderate in number in anteroventral margin.
Marginal infold moderately broad along anterior and posterior margins, but narrow along
ventral margin. Vestibule present along
entire free margin, but narrow along ventral

and posterior margins. Hinge holamphidont. Muscle scars consist of three frontal scars (middle one is very small) and a row
of four adductor scars: an elongated dorsal
scar, two divided dorso- and ventromedianscars, and an elongated ventral scar. Sexual
dimorphism distinct: males more slenderthan females. In younger juveniles, posteriorcardinal rims, subcentral tubercle, and radiating anterior ridges are very prominent.
Types and Dimensions.-Holotype:female RV, Loc. HIR-5S, IGPS 101824, Figs.
13-8a-c, L= l.l26 mm, H=0.631 mm; paratypes: female LV, Loc. SUN-IS, IGPS
101822, Figs.13-6a-b, L= 1.226 mm, H=
0.638 mm; male LV, Loc. HIR-3S, IGPS
101821, Fig. 13-5, L= 1.143 mm, H =.0.606
mm; male RV, Loc. HIR-3S, IGPS 101823,
Figs. 2-21,13-7, L= n63 mm, H=0.579 mm.
Type locality.-Upper Pliocene Sasaoka
Formation, Loc. HIR-5S.
Occurrence.- This species was found by theauthor only from the late Pliocene Sasaoka
and late Miocene Fujikotogawa Formations.
Remarks.- This species is possibly related
to Ambostracon sp. 1 of Tabuki (1986). It
resembles Patagonacythere robusta, but has
conspicuous reticulation, no posterodorsal or
ventral ribs, and a thinner valve anterior. It
is also similar to Daishakacythere posterocostata, but has fewer pores along the valve
margin and posterior denticles.
Acknowledgments
The author would like to express his deep
gratitude to Professor Kunihiro Ishizaki ofthe Institute of Geology and Paleontology,
Faculty of Science, Tohoku University, foradvice and continuous encouragement
throughout the course of the present study
and for critical reading of the manuscript.
Deep appreciation is also expressed to Emeritus Professor Y okichi Takayanagi and Professor Tsunemasa Saito of the same institute for
their suggestions and discussions concerning
various aspects of this study. The author is955.

Morphology of hemicytherin Ostracoda

much indebted to Dr. Thomas M. Cronin of
the U.S. Geological Survey and Professor
Noriyuki Ikeya of Shizuoka University forsuggestions and discussions concerning thetaxonomy, and for loaning samples from off
Hamatonbetsu and Funka Bay. Sincere
thanks are also due to Drs. Osamu Sasaki andShinji Tsukawaki of the Institute of Geology
and Paleontology, Faculty of Science, Tohoku University, Dr. Masafumi Arita and Mr.
Hajime Katayama of the Geological Surveyof Japan, and Mr. Tomohisa Nishizuka of
Idemitsu Cooperation for their supply ofsamples from the Omma Formation, Otsuchi
Bay, Toyama Bay, and the Setana Formation,
respectively. Acknowledgments are also due
to Messrs. Shohei Otomo and Jun Nemoto of
the Institute of Geology and Paleontology,
Faculty of Science, Tohoku University, fortheir photographic assistance. A part of thisstudy is supported financially by the
Katayama Memorial Scholarship from Tohoku University.

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Hokkaido ~Uil.h!t Hamatonbetsu ~~JL'i]IJ, Yakumo i\~t Setana WitJlll, Funka Bay 1IJl!:;kf.%',Aomori w~, Mutsu Ilf~, Hamada ~ 83, Namioka i,& 1lD:I, Daishaka fR i1d!l, Iwate:!fi~,Ninohe =. p, Shitazaki 15~, Akita 1';1\ 83, Kamikoani 1::. 'J' ~iiJ t:, Fujikotogawa iii ~ )1/,
Oga ~!'Iit, Anden
83, Shibikawa ~ JII, Gojonome 11.:!1iX; EI, Sasaoka t£E 1lD:I, Tentokuji:R:ff(f.=jf, Otsuchi Bay *lli[f.%', Toyama Bay %LlJf.%', Ishikawa E)I/, Kanazawa ~iR, Omma *

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955.

Morphology of hemicytherin Ostracoda

211

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chinella, Hemicythere, lohnnealella, Norman icy there, Patagonacythere, Urocythereis?) 0)
21 f!v':',,:)\.'-Z:, -th-fhO)WJ;jj\:~~, %9J~m, ~1i, -t L-Z:=EJIH~O)Jf~tili~~*lHv,:,W<lJ"'"'tc.o~JZFB*m"'to) RX;Jt)jj)JI1\' v':';f; vt Q OC{tiJ;, Hemicytherinae:<!EM J'tM!R 0) 5j-~~jIfU: Vc, itc.*®tl*lf,f- ~~~-t Q 1: -C·~~:lJtJ:=FiJ;iJ' I) ~~ X. Q .:::. ~~ L -z: \., Q 0 ~®:;f;.t lf~ill=B*'IB~O)RX;Jt:i&!f§H':';f;vtQ'i!l1:1:-C'O)5j-m/~!J - /'O)OC{tiJ'G, 21 f!lt 3 :J' /L-- -7'v':' i
6b G

c

c

hQ o I ~JIl, (Daishakacythere), 2 ~f! (Finmarchinella subrectangulata, Patagonacythere
sasaokensis) ~~~Ij L, §clftl!: L tc. o

Ayj f3!:~

212--------------------------------- 0 ---------------------------------

Erratum

UENO, KA TSUMI
Permian foraminifers from the Takakurayama Group of the southern
Abukuma Mountains, northeast Japan. Trans. Proc. Pa/aeont. Soc.
Japan, N.S., no. 168, p. 1265-1295, December, 1992.
On page 1289, in the explanation of Figure 11, line 3 from bottom. For
Agathammina maxima, read Agathammina magna.

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Transactions and Proceedings of the PalaeontologicalSociety of Japan

June 30, 1993

New Series No . 170

CONTENTS
TRANSACTIONS
953.

Katsumi Ueno and Yoshihiro Mizuno : Middle and Upper Carboniferous

954.

Takami Nobuhara : The relationship between bathymetric depth an d climate

fusulinaceans from the Tais haku Limesto ne Group , so uthwest Japan ...... 133
change and its effect on mo ll uscan faunas of the Kakegawa Group, central
Japan . ....... ... . .... . . .............................. . .......... . .. 159
955.

Toshiaki Irizuki : Morphology and taxonomy of some Japanese hemicytherin
Ostracoda -with particular reference to ontogenetic changes of marginal

pores- .. . . ................. . .. . ... .... . . ........ . .............. . .. 186