ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan

New SeriesNo. 178

June 30, 1995

Co-Editors

Kei Mori and Kunihiro Ishizaki

Language Editor

Martin Janal (New York)

Editorial Board

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

Officers for 1995- 1996

President : Tsunemasa Saito
Honorary President: Teiichi Kobayashi
Councillors : Kiyotaka Chinzei , Takashi Hamada, Yoshikazu Hasegawa, Itaru Hayami, Hiromichi Hirano,
Hisayoshi Igo, Noriyuki Ikeya, Junji Itoigawa, Tomoki Kase, Tatsuaki Kimura, Itaru Koizumi, Kei Mori ,Hiroshi Noda, Ikuwo Obata, Kenshiro Ogasawara, Tomowo Ozawa, Tsunemasa Saito, Yokichi
Takayanagi, Kazushige Tanabe, Akira Yao
Members of Standing Committee : Kenshiro Ogasawara (General Affairs), Tomoki Kase (Finance), Kei Mori (Editor in
Chief, TPPSJ), Kunihiro Ishizaki (Co-Editor, TPPSJ), Hiromichi Hirano (Planning), Hiroshi Noda (Membership ;Co-Editor, Special Papers), Noriyuki Ikeya (Foreign Affairs), Kazushige Tanabe (Editor, "Fossils"), Juichi Yanagida(Editor in Chief, Special Papers), Tatsuaki Kimura (Friends of Fossils)

Secretaries : Katsumi Ueno, Shuko Adachi (General Affairs), Masanori Shimamoto (Editorial of TPPSJ), Yasunari
Shigeta (Finance), Makoto Manabe (Planning), Katsuo Sashida (Membership), Robert M. Ross (Foreign Affairs),
Kazuyoshi Endo (Editorial of "Fossils"), Akihiko Matsukuma, Takeshi Ishibashi (Editorial of Special Papers),
Tamiko Ohana (Friends of Fossils)
Auditor: Ryuichi Majima

Cover: A terminally resorbed maxillary tooth of iguanodontids (Ornithischia: Ornithopoda).

The specimen isfrom the Kuwajima Formation, the Neocomian section of the Tetori Group, in Shiramine-mura,
Ishikawa County, Ishikawa Prefecture, the west coast of Central Honshu, Japan (Shiramine-mura
Board of Education, Coil. Cat. No. SBEI 001, 23 mm in dorsoventral length).

All communication relating to this journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPANc / o Business Center for Academic Societies,
Honkomagome 5- 16- 9, Bunkyo-ku, Tokyo, 113 Japan

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 178, pp.89-104, 4 Figs., June 30, 1995

Redescription of Asano and Nakamura's (1937)
cassidulinid species based on their primary types
SHIRO HASEGAWA and RITSUO NOMURA
Laboratory of Geosphere Science, Graduate School of Environmental Earth Science,
Hokkaido University, Sapporo, 060 Japan
Department of Micropaleontology, Faculty of Education, Shimane University, Matsue, 690 Japan

Received 26 February 1994; Revised manuscript accepted 6 March 1995
Abstract. Asano and Nakamura (1937) described 14 cassidulinid species and subspecies found in
Pliocene to Recent marine sediments of Japan. They stored these type specimens in the collectionof Tohoku University. However, Asano and his colleague's collection including the cassidulinid types
has not been well organized, as reported by Hasegawa (1986). During his investigation of theforaminiferal collection, Hasegawa found the holotype, paratype and hypotype specimens of thespecies published in 1937. Since these specimens have not been available for later systematic
works such as Nomura (1983a, b), herein we redescribe Asano and Nakamura's holotype andhypotype specimens in order to supplement Nomura's work, and revise taxonomically these species
according to the modern foraminiferal systematics.
Reexamination reveals that Cassidulina subglobosa parva is a synonym of Cassidulina decorata
Sidebottom. Globocassidulina parva as described by Nomura (1983b) is in part synonymous with
Globocassidulina canalisuturata Eade (1967) from Recent sediments off New Zealand.
Key words: Cassidulinid foraminifera, type specimens, Pleistocene, Recent, Japan
Introduction
The foraminiferal family Cassidulinidae d'Orbigny iswidely distributed in inner neritic to deep-sea sediments
throughout the Cenozoic Era. Since Yabe and Hanzawa(1925) described a new species of Cassidulina, more than80 species-group taxa (species and subspecies) belonging to eleven genera have been reported in and around theJapanese Islands. Among them, nine species-grouptaxa were described in the first published monograph ofthe cassidulinids from Japan by Asano and Nakamura(1937). One of the present authors (R.N.) has examined indetail the external and internal morphology of 76
Japanese cassidulinid species based on topotypic materials of Pliocene to Recent age (Nomura, 1983a, b).
The late Professor K. Asano of Tohoku University andhis colleagues originally described more than 300
species-group taxa mainly from Japan, most of whichhave been reported repeatedly by subsequent workers.
The original specimens including his holotypes and paratypes are stored in the foraminiferal collection of theInstitute of Geology and Paleontology, Tohoku University
in Sendai. However, Asano's collection including thecassidulinid specimens of Asano and Nakamura (1937)
has not been well organized until now, because of someproblems including an imperfect curatorial system for
microfossils.
After the publication of Nomura (1983a, b), one of thepresent authors (S.H.) found several foraminiferal slides
with the type specimens of Asano and Nakamura's
Cassidulina in Asano's collection during a taxonomic
study on Japanese late Cenozoic foraminifera (Hasegawa,1986). They are associated with registered numbers of
the Institute of Geology and Paleontology, Tohoku University, Sendai ("I.G.P.S. Coil. Cat. No." or "IGPS number"), as
shown in Table 1. Since such numbers are usually given
for describing new taxa, the specimens with the registerednumber should be primary types. We compared these
specimens with the original descriptions by Asano andNakamura (1937), and determined the type specimens of
their taxa.
A single specimen of the following species is isolated
from other specimens and mounted in a slide with an IGPS
number: Cassidulina japonica, C. setanaensis, C. sublimbata, C. yabei and C. wakasaensis. The morphologic
features of each species correspond to these of the typefigures and description given by the original authors.
Therefore, we confirmed that it is the holotype, and thatthe specimens in the other slides are paratypes. Anotherisolated specimen of C. japonica and C. sublimbata each90

Shiro Hasegawa and Ritsuo Nomura
Table 1. Type specimens of cassiduline species described by Asano and Nakamura (1937) in Asano's
collection of Tohoku University.
Cassiduline species ofAsano and Nakamura (1937)

C. japonica Asano and Nakamura

Original registration(and figures)
21434 (PI. 13, figs. la-c)(PI. 13, figs. 2a-c)(text-figs. 2a, b)
21435 (PI. 14, figs. la, b)

C. yabeiA& N

C. sublimbata A & N
C. setanaensis A & N

21436 (PI. 14, fig. 3)(PI. 14, figs. 4a, b)
21437 (PI. 13, figs. 7a, b)
21438 (PI. 14, figs. 2a, b)

C. kazusaensis A & N

Revised registration(and number of specimens)
21434A (I)21434B (I)
2 I434C-E (71)21435A (I)21435B (I)21435C-D (31)21436A (I)
21436B (I)21436C-E(44)21437A (I)21437B-C (76)21438A (I)21438B (I)21438C (I)21438D (35)

Recent, Japan Sea
holotypeparatype (flKured) Pleistocene, Sado Islandparatypes~imen not foundholo~

Iparatype (fiKured)* ex 21435D
para~

holo~
-,,-ar~ (fiKured)C. pacifica Cushman
C. wakasaensis A & N

21439 (PI. 14, fi~s. 5a, b)(PI. 14, fi~s. 6a, b)(PI. 13, fi~s. 3a, b)
21140 (PI. 13, figs. 5a, b)
21441 (PI. 13, fi~s. 8a, b)(PI. 13, fi~s. 6a-c)
21442 (PI. 14, fi~s. 7a-c)

Pleistocene, Sado Island
Pleistocene, SW Hokkaido

para~

holo~
para~

hol~

I,,-ara~ (fiKured)* ex 21438D
l"-ara~(fiKured)*ex 21438D~~

not ~stered (removed from holotype slide)(I)

C. saRamiensis A & N
C. orientale Cushman
C. SubRlobosa Brady
C. SUbRlobosa /Jarva A & N
C. SUbRlobosa de/Jressa A & N

Remarks

Types

not chan~ed (I)102540 (1)*102542 (1)*not chan~ed (1)not chan~ed (1)102543 (1)*(5)
21442A (I)21442B-D (931)

holo~

~
~
holo~
holo~

hypotype
not~steredholotype-,,-ara~C. altemans Yabe and Hanzawa

63670

not changed (1)holotype

C. laevigata d'Orbigny (7)(PI. 13, figs. 4a, b)
I(text-fi~s. 12a b)102541 (1)*hypotype

text-figs. a and b of Yabe and Hanzawa (1925)
specimen not found* desIgnated in thIS study

is mounted without number. Judging from its morphologic similarity to the original illustrations and from its
described locality, we recognized it as the paratype drawn
in the original paper of Asano and Nakamura (1937).
Two specimens of Cassidulina kazusaensis are stored
in one slide with registered numbers. Since these specimens differ markedly in their test morphology, theholotype specimen is identified carefully based on theoriginal description of Asano and Nakamura (1937).
Cassidulina sagamiensis, C. subglobosa parva and C.
subglobosa depressa are each represented by a single
specimen with a registered number. Therefore, eachspecimen is the holotype without any original paratypes.
The type specimen of C. alternans Yabe and Hanzawa(1925), whose original description was quoted in Asanoand Nakamura (1937), is also found in the collection. We
confirmed it as the holotype on the basis of its registerednumber and morphologic similarity to the original description and figures.
In addition to these, the following four specimens illustrated in their 1937 paper were also found: Cassidulina
orientale Cushman, C. subglobosa Brady, C, laevigata

d'Orbigny (7) and C. pacifica Cushman.
Among the forms illustrated by the original authors, thefollowing two have not been recovered in Asano's collection as yet: A paratype specimen of Cassidulina japonica
from an unknown locality (text-figs. 2a, b), and a specimen of C. laevigata d'Orbigny (7) collected from Ishikawa
Prefecture (text-figs. 11a, b).
Through the reexamination, we recognized that mosttaxa have been treated well in Nomura (1983a, b), except
for one subspecies, Cassidulina subglobosa parva(= G/obocassidulina parva of Nomura, 1983a, b). This
species has been obviously misunderstood by many
workers. In this paper, we attempt to redescribe themorphologic features of the original specimens of Asanoand Nakamura following the modern systematics of Loeblich and Tappan (1992). Also, we redescribe the otherreported taxa in their paper, for which subsequent workers
had to rely on the insufficient descriptions of Asano andNakamura (1937).
All the species described by Asano and Nakamura(1937) are reillustrated with SEM micrographs which aretaken with a low vacuum SEM in a coating-free condition,

987.

Redescription of Asano and Nakamura's cassidulinids

except for the two unrecovered specimens of C. japonica
and C. laevigata (?). We also give optical micrographs todemonstrate the external appearance of the inner structures of some species.
All of the paratypes and hypotypes of Asano andNakamura (1937) are newly registered in the collection of
Tohoku University. The original registered numbers arerevised by adding "An to the end of the number as IGPS
21434A for all the holotypes accompanied by paratypes.
A series of paratypes in a species is registered under thesame number as the holotype with a suffix letter (eg.,21434B, 21434C, ... ). Paratypes are numbered for slides
in which one or more speCimens are stored. For thosespecies based on a single specimen (i.e., automatic
holotype), the registered number is not changed.

Systematic descriptions
Class Foraminiferea, J.J. Lee, 1990
Order Buliminida Fursenko, 1958
Superfamily Cassidulinacea d'Orbigny, 1839
Family Cassidulinidae d'Orbigny, 1839
Subfamily Cassidulininae d'Orbigny, 1839
Genus Islandiella N¢rvang, 1959

Islandiella japonica (Asano and Nakamura)[Original designation: Cassidulina japonica
Asano and Nakamura]
Figures 1-1a-2d
Cassidulina japonica Asano and Nakamura, 1937, p. 144, text-

figs.2a, b; pI. 13, figs.1a-c, 2a-c; Asano, 1939, p.45,
text-fig. 3; Asano, 1951, p. 1, figs. 3, 4; Matsunaga, 1963,
pI. 48, figs.4a, b; Ishiwada, 1964, pI. 7, fig. 99.
Cassidulina californica Cushman and Hughes var. japonica
Asano and Nakamura. Ishiwada, 1950, p. 192, figs. 11a, b.
Islandiella japonica (Asano and Nakamura). Troitskaja, 1970,
p. 150, pI. 6, figs. 3, 4; Nomura, 1983a, pI. 4, fig. 6, pI. 6, fig.
1; pI. 10, figs. 4-10; 1983b, p.2, pI. 1, figs.1a-c, 2a-c.

Redescription of holotype.- Test large, nearly circularin side view, except for last-formed chamber which isslightly projected, and elongate oval in edge view;
periphery narrowly rounded, slightly lobulate; chambers
broadly elongate, four pairs in last-formed whorl, somewhat inflated; umbilical region closed, depressed;
sutures distinct, limbate, depressed, gently curved; aperture narrowly elongate, with cristate tooth whose tip isserrated, and with tongues at the base of apertural face;wall smooth, matte, and polished. Length 1.24 mm, width
1.09 mm, thickness 0.59 mm.
Types.-Holotype: IGPS 21434A. Figured paratype:
IGPS 21434B (PI. 13, figs.2a-c of Asano and Nakamura).
Other paratypes: IGPS 21434C (19 specimens), IGPS
214340 (30) and IGPS 21434E (22).
Type localities.-Holotype and unfigured paratypes(IGPS 21434A and C): Urashima-sho (= Urashima Bank)
St. 5, Wakasa Bay, southern part of the Japan Sea (198 m
in water depth; Asano, 1939). Figured and unfigured

91

paratypes (lGPS 21434B, 0 and E): Sawane, Sado Island,
Niigata Prefecture.
Type level.-Holotype: Recent. Paratypes: Recent,and Sawane Formation (= Shichiba Formation of early
Pleistocene age).
Observations.-Five original slides labeled "Cassidulina
japonica" are found in Asano's collection. Two of them
are labeled as collected from the Urashima Bank, andthree are from the Sawane Formation. The holotype
speCimen is isolated from the other 19 speCimens(= paratypes) by the original authors and is stored in oneof the two slides containing the Urashima Bank specimens. One specimen collected from the Sawane Formation is also isolated from 52 specimens in the remaining
two slides of the same locality. The fourth from lastchamber of this specimen is partially depressed by some
accident as shown in Figures 1-2a and 2d. Because thesame feature was illustrated by Asano and Nakamura(1937), this specimen is aSSignable to the figured paratypeof the original authors. Another specimen illustrated by
Asano and Nakamura (1937; text-figs.2a and b) has notbeen found in Asano's collection as yet.
As already pointed out by Nomura (1983b) based on theillustrations of Asano and Nakamura (1937), the holotype
has a depressed umbilicus and distinctly inflated chambers, whereas the figured paratype does not show suchfeatures. Such differences are also recognized among
the unfigured paratypes. The Recent specimens fromthe Urashima Bank are characterized by tests with aclosed (or very small) and depressed umbilicus, depressed
sutures, and four to five pairs of inflated chambers in the
final whorl. On the other hand, the specimens from the
Pleistocene Sawane Formation have a small stellate
umbilicus and more limbate sutures flush with the test
surface except for the last-formed chambers. They arecomposed of four pairs of chambers in the nepionic stage,
but five to six pairs in the neanic and gerontic stages.
The Pleistocene specimens are somewhat similar to I.
californica (Cushman and Hughes), but are distinguishedfrom the latter in having a less globular test with anarrowly rounded periphery, and a greater number ofchambers per whorl.
In this species, Nomura (1983b) recognized two types ofaperture on the basis of different style of its primary
tongue which is externally connected to a cristate tooth.
This feature is clearly shown in the holotype figure but notin the paratype figure. However, our reexamination of the
figured paratype reveals that the primary tongue wasbroken off, possibly by some accident. The primary
tongue is distinct in both of the Recent and Pleistocene
unfigured paratypes.
In conclusion, the type series of "C. japonica" consistsof two morphotypes on degree of chamber inflation; one
with inflated chambers includes the holotype from the
Recent sediment, the other has less inflated chamber as
does the figured paratype of the Pleistocene. The former
has been reported from the Pliocene in Niigata Prefectureby Matsunaga (1963), too. Alternately, the latter form
occurs in the Recent Toyama Bay (lshiwada, 1950). All

Shiro Hasegawa and Ritsuo Nomura

92

previous workers have regarded both morphotypes as
falling within the range of variation of a single species.
To the contrary, it may be possible that they represent two
different species. Such a possibility could be confirmed
in future through detailed morphometric analyses or variation studies in morphology. In this moment, we tentatively regard them as intra~pecific variants.

gate slit is developed at the base of the apertural face. It
is almost parallel to the plane of coiling and has a fanshaped cristate tooth and this apertural ridge (82 typeaperture of Nomura, 1983a).

Islandiella kazusaensis (Asano and Nakamura)[Original designation: Cassidulina kazusaensis
Asano and Nakamura]

Figures 1-3a-d

Figures 3-1a-3
Cassidulina kazusaensis Asano and Nakamura, 1937, p.146,
text-figs.7a, b; pI. 14, figs. 2a, b; Asano, 1938a, p.78, pI.
8, figs. 8a, b; Asano, 1951, p.2, figs. 7, 8.
Islandiella kazusaensis (Asano and Nakamura). Nomura,
1983a, pI. 11, figs. 10, 11 ; 1983b, p.6, pI. 1, figs. 5a-c.
Redescription of holotype.- Test large, subglobular inoutline, nearly circular in side view, last chamber broken,
oval in edge view; periphery narrowly rounded, notlobulate; chambers distinct, suboval in side view, notinflated, seven pairs in last-formed whorl, gradually
increasing in size as added; sutures distinct, notdepressed, radiate, but slightly curved near periphery,
flush with surface; umbilical region stellate, notdepressed; apertural opening hidden by secondary fillings of sediments; wall smooth, finely perforate, polished,translucent. Length 0.99 mm, width 0.90 mm, thickness
0.56 mm except for last chamber.
Types.-Holotype: IGPS 21438A. Figured paratypes:
IGPS 214388 and C (selected from IGPS 214380 in thepresent work). Other paratypes: IGPS 214380 (35).
Type locality.-Mitsumata, Fusamoto-mura (= presently
Mitsumata, Otaki-machi), Isumi-gun, Chiba Prefecture.
Type level.-Kiwada Formation (early Pleistocene).
Observations.- Two cassidulinid specimens aremounted in the type slide of Cassidulina kazusaensis with
the IGPS collection number of 21438. One is characterized by a large test with features which are well agreeablewith the type description and illustrations given by theoriginal authors, thereby enabling us to easily recognize it
as the holotype. On the contrary, the other specimen ischaracterized by a medium test size, a lobulate periphery,
inflated chambers, depressed sutures, and a tripartite
aperture indicating a different speCies. We identified it
as G/obocassidulina bisecta Nomura, 1983a; thus weremoved it from this original slide.
All the paratypes contained in the other slides exhibit
similar features to the holotype in their test morphology.
Although details of the apertural structure of the holotype
is not clear, the paratype specimens show that an elon-

Islandiella setanaensis (Asano and Nakamura)[Original designation: Cassidulina setanaensis
Asano and Nakamura]

Cassidulina setanaensis Asano and Nakamura, 1937, p. 146, pI.
13, figs.7a, b; Asano, 1951, p.3, figs. 15, 16: Ishiwada,
1964, pI. 7, fig. 100.
Cassilamellina setanaensis (Asano and Nakamura). Saidova,
1975, pI. 91, fig.1, pI. 115, fig. 9.
Cassidulina (?) lomitensis (Galloway and Wissler). McCulloch, 1977, p. 391, pI. 163, figs. 3a-c.
Islandiella setanaensis (Asano and Nakamura). Nomura,
1983a, pI. 3, fig. 6; pI. 4, figs. 3, 4; pI. 10, fig. 11; pI. 11,
figs. 1-3; 1983b, p.5, pI. 1, figs. 3a-c.
Redescription of holotype.- Test large, nearly circularin side view, oval in edge view; periphery rounded, notlobulate; chambers broad, not inflated, six pairs making
up last-formed whorl; sutures distinct, flush with surface;umbilical region filled with clear stellate shell material;
aperture an elongate slit at base of apertural face, runningparallel to plane of coiling, having a broken cristate toothand well developed apertural ridge; wall smooth, polished, very finely perforate. Length 1.45 mm, width 1.25mm, thickness 0.85 mm.
Types.-Holotype: IGPS 21437A. Paratypes: IGPS
214378 (58 specimens), IGPS 21437C (18).
Type locality.-Maruyama, Higashisetana-mura(=presently Maruyama, Aichi, Kitahiyama-machi),
Setana-gun, Hokkaido (St. 152 in Asano, 1937; St. b of
the Setana district in Asano, 1938c).
Type level.-Setana Formation (early Pleistocene).
Observations.- The holotype is isolated on a separate
slide by the original authors. The paratypes (76 specimens in total) were found in two other slides together withseveral specimens of other species, such as I. japonica,
Lenticulina spp. and Guttulina spp. Those erroneously
included specimens were removed to a new slide by us.
Islandiella setanaensis is closely related to I. japonica,
particularly in their younger stages, but this species isdistinguished by its larger number of chambers per whorl;
I. setanaensis has 5.5 pairs, whereas I. japonica has 4 to
5 pairs of chambers per whorl in younger stages. So far
as fully mature specimens are concerned, C. setanaensis
differs from C. japonica in having the test with a broadly
rounded and nonlobulate periphery and flush sutures.

Figure 1. 1-2. Islandiella japonica (Asano and Nakamura), 1 : holotype (IGPS 21434A), from Wakasa Bay (Recent,
198 m), 2: paratype (IGPS 21434B), from Sado Island (Sawane Formation, early Pleistocene). 3. Islandiella setanaensis(Asano and Nakamura), holotype (IGPS 21437 A), from Kitahiyama, Hokkaido (Setana Formation, early Pleistocene). 4.
Islandiella wakasaensis (Asano and Nakamura), holotype (IGPS 21442A), from Wakasa Bay (Recent, 190 m). a and b=
both sides views, c=edge view, d=optical micrograph showing umbilical region. Scale bars are 100 ,urn.

987.

Redescription of Asano and Nakamura's cassidulinids

93

Shiro Hasegawa and Ritsuo Nomura

94

Islandiella sublimbata (Asano and Nakamura)[Original designation: Cassidulina sublimbata

Asano and Nakamura]
Figures 2-1a-2d
Cassidulina sublimbata Asano and Nakamura, 1937, p.146, pI.
14, figs. 3, 4a, b; Asano, 1951, p.5, figs. 23, 24; Matsunaga, 1963, pI. 48, figs. 12a, b.
Cassidulina translucens Cushman and Hughes. Ishiwada,
1964, pI. 7, fig. 102.
Cassandra sublimbata (Asano and Nakamura). Saidova, 1975,
pI. 92, fig. 2.
Islandiella translucens (Cushman and Hughes). Hasegawa,
1979, p. 150, 151, pI. 4, figs.4a-c.
Islandiella sublimbata (Asano and Nakamura). Nomura, 1983a,
pI. 3, fig.7; pI. 4, fig.2; pI. 5, fig.7; pI. 9, figs. 1-8 ;1983b, p.9, pI. 1, figs. 6-c, 7a, b, 8a, b.
Redescription of holotype.- Test large, nearly circularin side view, lenticular in edge view, but nearly flat inumbilical region, showing parallel appearance in bothsides; periphery narrowly carinate, very slightly lobulate
only in last pair of chambers; chambers distinct, elongate, not inflated, six pairs making up last-formed whorl;
sutures distinct, limbate, not depressed, tangentiallycurved toward periphery; umbilical region with clear shellmaterial, showing earlier chambers as well as microspheric proloculus; aperture elongate, parallel to the plane ofcoiling, accompanied with a cristate tooth, well developed
lip, and apertural ridge; wall smooth, finely perforate,
polished. Length 0.83 mm, width 0.74 mm, thickness
0.36mm.
Types.-Holotype (microspheric form): IGPS 21436A.
Figured paratype (megalospheric form): IGPS 21436B (PI.
14, figs. 4a, b of Asano and Nakamura). Other paratypes:
IGPS 21436C (microspheric: 1 specimen, megalospheric:3 specimens), IGPS 21436D (microspheric: 27, megalospheric: 11) and IGPS 21436E (megalospheric: 2).
Type localities.-Holotype and unfigured paratypes(IGPS 21436A and C): Sawane, Sado Island, Niigata
Prefecture. Figured and unfigured paratypes (IGPS
21436B, D and E): Maruyama, Higashisetana-mura(=presently Maruyama, Aichi, Kitahiyama-machi),
Setana-gun, Hokkaido (St. 150 in Asano, 1937; St. c of
the Setana district in Asano, 1938c).
Type level.-Holotype: Sawane Formation (=Shichiba
Formation; early Pleistocene). Paratypes: Sawane andSetana Formations (both of early Pleistocene).
Observations.-Five original slides of Cassidulina sublimbata, two from the Sawane Formation and three fromthe Setana Formation, were found. Of the two slides
from the Sawane Formation, one stores the holotype, andthe other includes four paratypes. One slide from the
Setana Formation contains the isolated specimen thatwas figured by the original authors. Other two slides
from the Setana Formation contain 40 paratypes in total.
Compared with the paratypes from the Sawane Formation,
those from the Setana Formation are characterized bymore narrowly elongate chambers, more limbate andslightly undulated sutures. We considered that thesemorphological differences fall within the range of variationof a single taxon. Megalospheric form has a large transparent umbilicus, where well developed pore tubules areseen to penetrate distinctly into the clear shell material
from the proloculus (Figure 2-1d). Such a feature is notdistinct in microspheric forms (Figure 2-2d).
Islandiella wakasaensis (Asano and Nakamura)[Original designatiqn: Cassidulina wakasaensis

Asano and Nakamura]
Figures 1-4a-c
Cassidulina wakasaensis Asano and Nakamura, 1937, p.149,
pI. 14, figs. 7a-c; Asano, 1951, p. 5, figs. 25, 26; Ishiwada,
1964, pI. 7, fig. 105; Chijiand Konda, 1970, pI. 9, fig. 4.
Islandiella wakasaensis (Asano and Nakamura). Nomura,
1983a, pI. 3, fig. 3; pI. 8, figs. 11, 12; 1983b, p. 11, pI. 2, figs.
la-c.
Redescription of holotype.- Test large, nearly circular,very slightly projecting in last chamber in side view,
lenticular in edge view; periphery acute, not carinate;chambers elongate, indistinct, not inflated except for laterones, six pairs making up last-formed whorl; suturesindistinct except for later ones, not depressed, undulate,tangentially slightly curved toward periphery; umbilicalregion indistinct; aperture narrow, elongate, nearly parallel to the plane of coiling, with serrated lip and cristate
tooth, and with undulated apertural ridge; wall smooth,polished, very finely perforate, opaque. Length 0.89 mm,
width 0.80 mm, thickness 0.47 mm.
Types.-Holotype: IGPS 21442A. Paratypes: IGPS
21442B (282 specimens), IGPS 21442C (277), IGPS 21442D(372).
Type locality.-Urashima-sho (Urashima Bank) St. 8,
Wakasa Bay, southern part of the Japan Sea (Water depth
190 m; Asano, 1939).
Type level.-Recent.
Observations.- The holotype is isolated from the paratype specimens and is mounted in one slide. A large
number of paratype specimens are stored in three slides.
The wall in most of the paratypes is opaque to semiopaque. Though it was regarded as a specific feature by theoriginal authors, transparency of the wall changes largely
due to the state of preservation as well as wall thickness,
as pOinted out before by one of the authors (Nomura,
1983a).

Figure 2. 1-2. Islandiella sublimbata (Asano and Nakamura), 1 : holotype (IGPS 21436A), microspheric form, from
Sado Island (Sawane Formation, early Pleistocene), 2: paratype (IGPS 214368), megalospheric form, from Kitahiyama,
Hokkaido (Setana Formation, early Pleistocene). 3-4. Islandiella yabei (Asano and Nakamura), 3: holotype (IGPS
21435A), microspheric form, 4: paratype (IGPS 214358), megalospheric form, all from Imakane, Hokkaido (Setana
Formation, early Pleistocene). Scale bars are 100 .um. [a-d, see explanation for Figure 1J

987.

Redescription of Asano and Nakamura's cassidulinids

95

Shiro Hasegawa and Ritsuo Nomura

96

Sutures of the paratypes are nearly straight to undulate,but not so tortuous as those of I. tortuosa (Cushman andHughes).

thickly calcified transparent umbilicus (Figures 2-4a-d)
as observed in C. sublimbata.
Genus Paracassidulina Nomura, 1983

Islandiella yabei (Asano and Nakamura)[Original designation: Cassidulina yabei
Asano and Nakamura]

Paracassidulina nipponensis (Eade)[Original designation: Cassidulina orientale Cushman]

Figures 2-3a-4d

Figures 3-4a-c

Cassidulina yabei Asano and Nakamura, 1937, p.145, pI. 14,
figs. 1a, b; Asano, 1951, p.5, figs. 27, 28; Voloshinova,
1952, p. 89, pI. 1, figs. 1Oa-c; Matsunaga, 1963, pI. 49, figs.
1a-2b; Ishiwada, 1964, p. 42, 43, pI. 7, figs. 103, 104; Chiji
and Konda, 1970, pI. 9, figs. 3a, b; Hasegawa, 1979, p.
145, pI. 8, figs.7a-c.
Islandiella yabei (Asano and Nakamura). Nomura, 1983a, pI. 3,
fig.1; pI. 4, fig. 7; pI. 9, figs. 9-12, pI. 10, figs. 1-3; 1983b,
p.7, pI. 1, figs. 4a-c, 9a, b. 'Not Cassidulina yabei Asano and Nakamura. Matoba, 1967, p.
253, pI. 28, figs. 8a, b, 9a, b; Kameyama, 1972, pI. 31, figs.
5a, b; Inoue, 1989, p.156, pI. 23, figs. 11a, b.

Cassidulina orientale Cushman, 1925, p.37, pI. 7, figs.6a-c(not of Cushman, 1922, p.128) [nom. nud.] ; Asano andNakamura, 1937, p.147, pI. 14, figs. 6a, b; Asano, 1951, p.
2, figs. 9, 10; Matsunaga, 1963, pI. 48, figs. 7a, b; LeRoy,
1964, p. F40, pI. 11, figs. 15, 16.
Globocassidulina nipponensis Eade, 1969 (part), p. 65, pI. 13,
figs. 1a-c, 2a-c, 4 (not fig. 3).
Not Cassidulinoides orientale [sic!]: (Cushman). Barker,
1960, p.112, pI. 54, figs. 1Oa-c.
Paracassidulina nipponensis (Eade). Nomura, 1983a, p. 97, pI.
2, figs. 20a, b; pI. 25, fig. 8.

Redescription of holotype.- Test large, nearly circularin side view, lenticular in edge view; periphery carinate,slightly lobulate; chambers distinct, not inflated, large
rounded-rhomboid, five pairs making up last-formed
whorl; sutures distinct, limbate, not depressed, flush withsurface, gently curved toward periphery; umbilical region
with clear shell material, showing earlier chambers as well
as microspheric proloculus; aperture elongate, extending
from the base of final apertural face, parallel to the planeof coiling, with fragile cristate tooth and thick apertural
ridge; wall smooth, finely perforate, transparent. Length
0.92 mm, width 0.78 mm, thickness 0.42 mm.
Types.-Holotype (microspheric form): IGPS 21435A.
Figured paratype (megalospheric form): IGPS 214358(selected from IGPS 214350 in the present work). Other
paratypes: IGPS 21435C (microspheric: 5 specimens,
megalospheric: 4 specimens), IGPS 214350 (microspheric: 15, megalospheric: 7).
Type locality.-Omagari, Toshibetsu-mura (=presently
Pirika, Imakane-machi), Setana-gun, Hokkaido (St. 107 in
Asano, 1937; St. c of the Hanaishi district in Asano,
1938c).
Type level.-Setana Formation (early Pleistocene).
Observations.-An isolated specimen (holotype) in aslide and 32 paratypes in two other slides were found in
Asano's collection. The paratypes have four to five pairsof chambers in the last-formed whorl. The megalospheric form clearly shows many pore tubules penetrating theRedescription of hypotype.- Test medium, compressed,
broadly oval in side view, both sides parallel in edge view;
periphery compressed-rounded, not lobulate; chambers
distinct, large, not inflated, five to six pairs in last-formed
whorl, tending in adult specimens to show uncoiling;sutures distinct, narrowly limbate, nearly straight, flushwith surface; umbilical region narrow, not depressed;
aperture a long, narrow slit at base of last apertural face,with distinct apertural ridge; wall smooth, very finely
perforate, polished, translucent. Length 0.46 mm, width
0.36 mm, thickness 0.14 mm.
Type.-Hypotype: IGPS 102540.
Type localities.-Hypotype: Kamimiyata, Minamishitaura-mura, Miura-gun (=presently Kamimiyata, Miura
City), Kanagawa Prefecture. Holotype of Cassidulina
nipponensis Eade: "Nero" station 1264, south of Japan
(3,806 m) (Cushman, 1925).
Type level.-Hypotype: Miyata Formation (middle
Pleistocene). Holotype of Cassidulina nipponensis
Eade: Recent.
Observations.-A single specimen labeled as Cassidulina orientale is stored in Asano's collection. As
pointed out by Nomura (1983a), the present form is identical to Cassidulina orientale Cushman, 1925. This
species name is judged to be a junior primary homonym of
C. orientalis Cushman, 1922 by Eade (1969) who proposed
the new name C. nipponensis for the former.

Figure 3. 1-3. Islandiella kazusaensis (Asano and Nakamura), 1: holotype (IGPS 21438A), 2: paratype (IGPS
21438B), tangential view showing penultimate aperture, 3: paratype (IGPS 21438C), apertural view. All from Mitsumata,Otaki, Chiba Prefecture (Kiwada Formation, early Pleistocene). 4. Paracassidulina nipponensis (Eade), hypotype of
Cassidulina orientale Cushman by Asano and Nakamura (1937), from Kamimiyata, Kanagawa Prefecture (Miyata
Formation, early Pleistocene), IGPS 102540. 5. Paracassidulina sagamiensis (Asano and Nakamura), holotype (IGPS
21439), from Kamimiyata, Kanagawa Prefecture (Miyata Formation, early Pleistocene). 6. Globocassidulina brocha(Poag), hypotype of Cassidulina laevigata d'Orbigny (?) by Asano and Nakamura (1937), from Yatsu, Yokohama,
Kanagawa Prefecture (Ofuna Formation, early Pleistocene), IGPS 102541. Scale bars are 100 ,um. [a-d, see explanation for Figure 1]

987.

Redescription of Asano and Nakamura's cassidulinids

97

Shiro Hasegawa and Ritsuo Nomura

98

Paracassidulina sagamiensis (Asano and Nakamura)[Original designation: Cassidulina sagamiensis
Asano and Nakamura]
Figures 3-5a-c
Cassidulina sagamiensis Asano and Nakamura, 1937, p. 147, pI.
14, figs. 5a-c; Asano, 1938b, p. 71, 84, 88, pI. 8, figs.9ac; Asano, 1951, p.3, figs. 13, 14; Higuchi, 1954, pI. 3, figs.
24a, b; Matsunaga, 1963, pI. 48, figs. 8a, b; Kikuchi,
1964, pI. 7, fig. 16; Matoba, 1967, p. 263, pI. 28, figs. 13a, b,
14a, b.
Paracassidulina sagamiensis (Asano and Nakamura). Nomura,
1983a, pI. 5, fig. 6; pI. 24, figs. 10-12; pI. 25, figs. 1, 2;
1983b, p. 67, pI. 6, figs. 1a-3.
Redescription of holotype.- Test medium, somewhat
compressed, subcircular in side view, elongate oval inedge view; periphery narrowly rounded, slightly lobulate;chambers distinct, large, slightly inflated, four pairs inlast-formed whorl; sutures distinct, narrowly limbate,
gently curved, slightly depressed; umbilical region narrow, slightly depressed; aperture a long-narrow slit with
distinct apertural ridge; wall smooth, very finely perforate,opaque; very short fine grooves running out of anterior
end of aperture. Length 0.51 mm, width 0.42 mm, thickness 0.23 mm.
Type.-Holotype: IGPS 21439.
Type locality.-Kamimiyata, Minamishitaura-mura,
Miura-gun (= presently Kamimiyata, Miura City), Kanagawa Prefecture.
Type level.-Miyata Formation (middle Pleistocene).
Observations.- There is no paratype specimen found in
Asano's collection. Nomura (1983b) pointed out that
Paracassidulina sagamiensis is characterized by a longnarrow slit-shaped aperture, a few apertural grooves on
the proximal portion of the aperture, and a small secondary tongue.

Genus Globocassidulina Voloshinova, 1960

Globocassidulina brocha (Poag)[Original designation: Cassidulina laevigata
d'Orbigny (?)]
Figures 3-6a-c
Cassidulina laevigata d'Orbigny (7). Asano and Nakamura,
1937 (part), p.150, pI. 13, figs. 4a, b (not text-figs. 11a, b).
Cassidulina brocha Poag, 1966, p.426, pI. 8, figs. 33-35.
G/obocassidulina brocha (Poag). Nomura, 1983a, pI. 18, figs.
8-12; Nomura, 1983b, p. 31, pI. 3, figs. 3a-5.

Not Cassidulina asanoi Uchio in Kawai et al., 1950, p. 190, fig.
13; Uchio, 1951, p. 39, 40, pI. 3, figs. 2a, b.
Redescription of hypotype.- Test medium, nearly circular in side view, biconvex; periphery subacute, slightly
lobulate; chambers elongate, very slightly inflated, four
pairs making up last-formed whorl, uniformly increasing insize as added; sutures distinct, narrowly limbate, tangentially curved toward periphery, slightly depressed;
umbilical region closed, very slightly depressed; aperture
crookedly elongate; wall very thin, finely perforate, translucent. Length 0.29 mm, width 0.25 mm, thickness 0.16mm.
Type.-Hypotype: IGPS Coil. Cat. No. 102541.
Type localities.-Hypotype: Yazu, Kanazawa-machi(=presently Yatsu, Kanazawa-ku, Yokohama City),
Kanagawa Prefecture. Holotype of Cassidulina brocha
Poag: S19, Chickasawhay River, Wayne County, Mississippi, U.S.A.
Type level.-Hypotype: Ofuna Formation (early Pleistocene). Holotype of Cassidulina brocha Poag: Paynes
Hammock Formation (Early Miocene ?).
Observations.-Only one specimen has been found in
Asano's collection. It is characterized by the biconvex
test with a subacute periphery and closed umbilicus,
which is in agreement with the illustration of Asano andNakamura (their plate 13, figs. 4a, b).
On the other hand, they illustrated another form of thisspecies in their paper (text-fig. 11 of Asano and Nakamura,1937), which has not been found in Asano's collection yet.
Uchio (1951) understood the difference in morphology
between two figures of Asano and Nakamura (1937), andidentified the present form with his new species, Cassidulina asanoi Uchio (Uchio, 1950, 1951). Later Uchio's
species has been regarded as a synonym of C. delicata
Cushman (= Takayanagia delicata) by many Japanese
workers (e.g., Ishiwada, 1964; Matoba, 1967; Nomura,
1983a). Though the original figures of Asano and Nakamura (1937; pI. 13, figs. 4a, b) are quite similar to Uchio's species, the original specimen is obviously distinguished from Cassidulina asanoi or C. delicata in having
less elongate chambers, and the crookedly elongate E2Type aperture with a tube-like lip, cristate tooth, and asecondary tongue.

Globocassidulina decorata (Sidebottom)[Original designation: Cassidulina subglobosa
Brady parva Asano and Nakamura]
Figures 4-3a-c

Figure 4. 1. Globocassidulina gemma (Todd), hypotype of Cassidulina subglobosa Brady by Asano and Nakamura(1937) from Kajigaya, Yokohama, Kanagawa Prefecture (Nakazato Formation, middle Pleistocene), IGPS 102542. 1a=apertural view, 1b=side view, 1c=ventral view. 2. G/obocassidulina depressa (Asano and Nakamura), holotype (IGPS
21441), from Semata, Ichihara, Chiba Prefecture (Yabu Formation, middle Pleistocene). 3. G/obocassidulina decorata(Sidebottom), holotype (IGPS 21140) of Cassidulina subglobosa parva Asano and Nakamura, 1937, from Nojima, Yokohama, Kanagawa Prefecture (Nojima Formation, early Pleistocene). 4. G/obocassidulina elegans (Sidebottom), holotype(IGPS 63670) of Cassidulina alternans Yabe and Hanzawa, 1925, from south of Okinawa Island (Recent, 1,580 m). 5.
Burseolina pacifica (Cushman), hypotype of Cassidulina pacifica Cushman by Asano and Nakamura (1937) from Kyoshito,
Takao Prefecture, Taiwan, IGPS 102543. 5a, b=edge and side views, 5c, d=optical micrographs in edge and ventral
views showing sutures. Scale bars are 100 ,um.

987. Redescription of Asano and Nakamura's cassidulinids

99

100

Shiro Hasegawa and Ritsuo Nomura

Cassidulina decorata Sidebottom, 1910, p.107, pI. 4, figs.2a-c(fide Ellis and Messina, 1944 et seq.).
Cassidulina subglobosa parva Asano and Nakamura, 1937, p.
148, pI. 13, figs. 5a, b; Asano, 1951, p.4, figs. 21, 22.
Cassidulina elegans Sidebottom var. bosoensis Kuwano, 1954,
p. 34, figs. 7 -11.
Cassidulina elegans bosoensis I(uwano. Matoba, 1967, p.
252, pI. 28, fig. 22.
G/obocassidulina decorata (Sidebottom). Eade, 1967, p.435,
fig. 5, no.1 ; Nomura, 1983a, pI. 17, fig. 8; 1983b, p. 27, pI.
2, figs. 14, 15a, b, 16.
Not Cassidulina parva Asano and Nakamura. Matsunaga,
1963, pI. 48, figs. 10a, b, 11a, b.
Not G/obocassidulina parva (Asano and Nakamura). Serava,
1978, p. 122, pI. 12, fig. 1; Nomura, 1983a, pI. 15, figs. 6-10;
1983b, p. 41, pI. 3, figs. 13a, b.
Diagnosis of C. subglobosa parva Asano and Nakamura.
-"The present form differs from the typical one in thesomewhat limbate sutures; it is quite identical with
Brady's subglobosa in the shape of aperture." (Asanoand Nakamura, 1937).
Redescription of holotype of C. subglobosa parva
Asano and Nakamura.- Test medium, subglobular;
periphery broadly rounded, lobulate; chambers distinct
on later, but indistinct in early portion, slightly inflated, fivepairs in last-formed whorl gradually increasing in size as
added; sutures somewhat indistinct in early portion,
narrowly limbate, slightly undulate, depressed; aperture
tripartite with a short basal slit, accompanied by cristate
tooth, poorly developed triangular apertural flap on anterior side, and thickened apertural ridge; wall decorated
with a network of irregular costae, except for final chamber wall. Length 0.34 mm, width 0.28 mm, thickness 0.31mm.
Type.-Holotype of C. subglobosa parva: IGPS 21140.
Type localities.-Holotype of C. subglobosa parva:
Nojima, Kanazawa-machi (=Nojima, Kanazawa-ku, Yokohama City), Kanagawa Prefecture. Holotype of Cassidulina decorata Sidebottom; Off southern Fiji (Lat.
19'04'N, Long. 179'43'E; Water depth 1,920 m) (fide Eade,1967). Holotype of Cassidulina elegans var. bosoensis
Kuwano: North of Kaisho, Oikawa-mura, Isumi-gun,Chiba Prefecture.
Type level.-Holotype of C. subglobosa parva: Nojima
Formation (early Pleistocene). Holotype of Cassidulina
decorata Sidebottom: Recent. Holotype of Cassidulina
elegans var. bosoensis Kuwano: Kiwada Formation (early
Pleistocene).
Observations.-A single specimen labeled as Cassidulina subglobosa parva with the IGPS number of 21140
was found in Asano's collection, thus it is recognized as
the holotype of this taxon.
The present specimen clearly shows reticulate ornamentation on the test surface and the tripartise slit of theaperture. Because such features were not described,
and because this taxon was treated as a subspecies withlimbate sutures of Cassidulina subglobosa by the original
authors (Asano and Nakamura, 1937; Asano, 1951), thesystematics of this taxon has been misunderstood by later

workers.
Kuwano (1954) erected a new taxon, bosoensis, for aform similar to the present specimen from Pleistocene
deposits of the Boso and Miura Peninsulas, as a reticulate
variety of Cassidulina elegans Sidebottom. To the contrary, Takayanagi and Hasegawa (1987) observed the typespecimens in Asano's collection, and regarded C. elegans
bosoensis as a junior synonym of C. subglobosa parva
Asano without any comment.
Nomura (1983b) described Cassidulina elegans
Sidebottom var. bosoensis Kuwano as a junior synonym of
G/obocassidulina decorata (= originally Cassidulina decorata Sidebottom, 1910) on the basis of the similar characterof the surface networking. Since Cassidulina subglobosa
parva Asano and Nakamura is a subjective synonym of
Kuwano's bosoensis, it is also a junior subjective synonym of Sidebottom'S species. On the other hand, theform referred to Cassidulina (or G/obocassidulina) subglobosa parva by several workers including Nomura(1983a, b) is quite different from Asano and Nakamura's C.
subglobosa parva. In a redescription based on many
topotypic material, Nomura (1985b) stressed that his G.
parva is characterized by U-shaped depressed sutures,
smooth test surface and a tripartite aperture. Such features are observed in G/obocassidulina canalisuturata,
which has been described from Recent sediments off New
Zealand by Eade (1967). One of the writers (R.N.)
examined the paratypes deposited in the New ZealandGeological Survey (NZGS Reg. No. TF 1559) and confirmed that it has an L-shaped aperture and narrow,depressed sutures like those of Nomura's G. parva.
Consequently, G. parva redescribed by Nomura (1983a, b)
should be referred to G. canalisuturata Eade.

Globocassidulina depressa (Asano and Nakamura)[Original designation: Cassidulina subglobosa
Brady depressa Asano and Nakamura]
Figures 4-2a-c
Cassidulina subglobosa depressa Asano and Nakamura, 1937,
p.148, pI. 13, figs. 8a-c; Asano, 1951, p.4, figs. 19, 20;
Kuwano, 1962, pI. 16, fig. 4; Ishiwada, 1964, pI. 7, fig. 98 ;Kikuchi, 1964, pI. 7, fig. 11.
Cassidulina subglobosa var. subcalifornica Draoger, 1953, p.
140, pI. 22, figs. 8a-c, 9.
G/obocassidulina depressa (Asano and Nakamura). Uchio,
1960, p. 68, pI. 9, figs. 18, 19; Parker, 1964, p. 624, pI. 99,
figs. 28a, b; Matoba, 1967, p. 252, pI. 28, figs. 19a-c ;Kameyama, 1972, pI. 31, fig. 4; Serova, 1978, p. 121, 122,
pI. 10, fig. 6; Nomura, 1983a, pI. 15, figs. 11, 12; pI. 16, figs.
1-4; 1983b, p.35, pI. 3, figs. 6a-c.
Smyrnella subcalifornica subcalifornica (Draoger). Saidova,
1975, p. 334, 335, pI. 88, fig. 8, pI. 115, fig. 1.
Cassidulina (?) cf. subcalifornica Drooger. McCulloch, 1977, p.
394, pI. 165, figs. 1a-c, 2a-c, 4a-c.
Not G/obocassidulina depressa (Asano and Nakamura).
Hasegawa, 1979, p.149, pI. 8, figs. 8a, b.
Redescription of holotype.- Test medium, compressed,
subcircular in side view, last chamber slightly protruded;

987.

Redescription of Asano and Nakamura's cassidulinids

periphery compressed-rounded; chambers distinct, oval,slightly inflated, four pairs in last-formed whorl, gradually
increasing in size as added; sutures distinct, slightly
depressed, moderately curved toward periphery; umbilical region closed, slightly depressed; aperture tripartite,
consisting of basal and areal branches, situated at base ofapertural face, associated with cristate tooth, thick lip andsecondary tongue, but without apertural ridge; wall thin,very finely perforate, polished, translucent. Length 0.32
mm, width 0.27 mm, thickness 0.15 mm.
Type.-Holotype: IGPS 21441.
Type 10cality.~Semata-shinden, Ichito-mura, Ichiharagun (= presently Semata, Ichihara City), Chiba Prefecture.
Type level.-Yabu Formation (middle Pleistocene).
Observations.-Only one specimen was found in
Asano's collection. It shows a much depressed test andthe distinctly tripartite aperture with a cristate tooth.

Globocassidulina elegans (Sidebottom)[Original designation: Cassidulina alternans
Yabe and Hanzawa]
Figures 4-4a-c
Cassidulina elegans Sidebottom, 1910, p.106, pI. 4, figs.1a-c(fide Ellis and Messina, 1944 et seq.); Cushman, Todd
and Post, 1954, p. 366, pI. 90, fig. 23.
Cassidulina alternans Yabe and Hanzawa, 1925, p.53, textfigs. a, b; Asano and Nakamura, 1937, p.149.
G/obocassidulina elegas (Sidebottom). Eade, 1967, p. 435, fig.
4, nos. 6, 7; Takayanagi et al., 1982, figs. X-8 (14,15).
Islandiella elegans (Sidebottom). Ujiie, 1990, p. 37, pI. 19, figs.
9a-10b.
Redescription of holotype of C. alternans Yabe andHanzawa.- Test medium, subglobular, slightly inequilaterally compressed; periphery broadly rounded in edge view,strongly serrate in side view owing to ridges on thechambers which move from an anterior position at thechamber periphery to midway across the chamber toward
the umbilical region; chambers distinct, slightly inflated,
five pairs in last-formed whorl gradually increasing in size
as added; sutures distinct, limbate, slightly raised; aperture a long narrow loop-like slit, slightly curved, extending
up nearly at right angles to the base of apertural face,surrounded by lip and cristate tooth; wall smooth, very
finely perforate, semiopaque, but translucent only inapertural region. Length 0.48 mm, width 0.43 mm, thickness 0.38 mm.
Type.-Holotype of C. alternans: IGPS 63670.
Type localities.-Holotype of C. alternans: St. 1116 of
the then Imperial Hydrographic Department of Japan (July17,1923), South of Okinawa Island (Lat. 25°50.7'N, Long.
127"25.6'E; Water depth 1,580 m). Holotype of Cassidulina elegans Sidebottom: Off southern Fiji (Lat.
19°04'N, Long. 179°43'E; Water depth 1,920 m) (fide Eade,1967).
Type level.-Holotype of C. alternans: Recent.
Holotype of Cassidulina elegans Sidebottom: Recent.
Observations.-Only one specimen of C. alternans

101

Yabe and Hanzawa is found in Asano's collection. It is
mounted in a slide with the registered number of 63670
written on a red-colored label, thus indicating theholotype slide, although no number was given in thepapers of either Yabe and Hanzawa (1925) or Asano andNakamura (1937). Furthermore, the morphologic featuresof this specimen correspond to these of the type figuresand description by Yabe and Hanzawa (1925). We thus
confirmed that it is the holotype.
Ujiie (1990) regarded C. alternans as a junior synonym of
Cassidulina elegans Sidebottom, 1910. On the contrary,
Cushman, Todd and Post (1954) regarded the two species
as different without further comment. The specimen of
C. alternans is characterized by a subglobular test having
a serrate periphery, with ridge-like chambers, limbate
sutures, and a slightly curved loop-shaped aperture.
Such morphological features of C. alternans are identicalto the descriptions of C. elegans. So far as can be
judged from the original descriptions of the two forms,
they are quite similar and hard to distinguish. In addition,
Yabe and Hanzawa (1925) did not refer to Sidebottom's
species of 1910.
Based on apertural features, C. alternans should betransferred to G/obocassidulina. Ujiie (1990) regarded thisspecies as an Islandiella on the basis of apertural characters and wall texture. Judging from his figures of thespecimens, however, their apertural feature is of the D3
Type of Nomura (1983a) which is recognized in the neanic
to early ephebic stages of G/obocassidulina and Burseolina. It is never found in Islandiella. In addition,
Ujiie's specimens are about 160 and 250 pm, respectively,in maximum length. In contrast, both the specimens ofSidebottom (1910) and Yabe and Hanzawa (1925) exceed
300 pm. Therefore, Ujiie's specimens should be of theyounger stages of G/obocassidulina elegans.

Globocassidulina gemma (Todd)[Original designation: Cassidulina
subglobosa (Brady)]
Figures 4-1a-c
Cassidulina subglobosa Brady. Asano and Nakamura, 1937,
p. 147, pI. 13, figs. 3a-c; LeRoy, 1941b, p. 85, pI. 6, figs. 16,
17.
Cassidulina gemma Todd. Cushman, Todd and Post, 1954, p.
366, pI. 90, figs. 26, 27.
Cassidulina subglobosa Brady var. Cushman, Todd and Post,
1954, p.367, pI. 90, fig. 33.
Globocassidulina gemma (Todd). Belford, 1966, p.147, pI. 24,
figs. 22-25, text-fig. 16, nos. 11, 12; Nomura, 1983a, pI. 12,
figs. 9,10; pI. 13, figs. 7-12; 1983b, p. 22, pI. 2, figs. lOa, b,
11.
Cassidulina (?) cf. gemma Todd. McCulloch, 1977, p. 389, pI.
167, figs. 8, 11, 12.
Redescription of hypotype.- Test medium, subglobular,slightly longer than broad, last-formed chamber somewhat
projected in the plane of coiling; periphery broadly
rounded, very slightly lobulate; chambers distinct except
for earlier portion, broad and rounded triangular in general

Shiro Hasegawa and Ritsuo Nomura

102

shape, very slightly inflated, four pairs in last-formed
whorl; sutures indistinct, but moderately curved; sutural
grooves visible at the base of apertural face, but not
depressed toward periphery; aperture elongate, loopshaped, at nearly a right angle to suture of apertural face,and oblique to the plane of coiling, surrounded by developed sulcus and lip; numerous grooves clearly visiblearound apertural margin, but not developed on anterior
portion of apertural face; wall polished, very finely perforate, semiopaque. Length 0.52 mm, width 0.42 mm,
thickness 0.47 mm.
Type.-Hypotype: IGPS Coil. Cat. No. 102542.
Type localities.-Hypotype: Oshikiri, Hongo-mura,
Kamakura-gun (=presently Kajigaya, Totsuka-ku, Yokohama City), Kanagawa Prefecture. Holotype of Cassidulina gemma Todd: Bikini 1172, Sylvania guyot, 1,528
m (Cushman, Todd and Post, 1954).
Type level.-Hypotype: Nakazato Formation (middle
Pleistocene). Holotype of Cassidulina gemma Todd:
Recent.
Observations.-Only one specimen of "Cassidulina
subglobosa" was found in Asano's collection. The present specimen is characterized by the test having inflatedchambers, sutural grooves at the base of the aperturalface, and apertural grooves. Based on these features,
this form is not assignable to G/obocassidulina subglobosa (Brady), but to G. gemma (Todd). It is also distinguished from G. oriangulata Belford and G. bisecta Nomura, both with a tripartite aperture, in having a loop-shaped
aperture at a near-right angles to the base of the final
apertural face.
Genus Burseolina Seguenza, 1880
Burseolina pacifica (Cushman)[Original designation: Cassidulina pacifica Cushman]almost parallel to periphery of final apertural face in front
view; wall smooth, very finely perforate, opaque. Length
0.33 mm, width 0.29 mm, thickness 0.31 mm.
Type.-Hypotype: IGPS Coli. Cat. No. 102543.
Type localities.-Hypotype: Kyoshito, Takao Prefecture, Taiwan (Formosa). Holotype of Cassidulina pacifica
Cushman: Challenger St. 185, Torres Strait, South
Pacific.
Type level.-Hypotype: Mud volcano (unknown age).
Holotype of Cassidulina pacifica Cushman: Recent.
Observations. -Six specimens of "Cassidulina pacifica"
are found in two slides. A specimen is isolated from theothers by the original authors themselves, and thus thefigured specimen is easily recognized in Asano's collection. It is safely identified as Burseolina pacifica byhaving a compact test with a smooth surface, not inflatedchambers, and a burseoline aperture.
Acknowledgments

We express our thanks to Prof. T. Saito of Tohoku
University, for critical reading of the manuscript and forallowing us to examine Asano's foraminiferal collection;
to Dr. B. Hayward of Aukland Museum, New Zealand, forthe loan of paratypes of G/obocassidulina canalisuturata :and to the late Dr. Y. Kuwano of the National Museum ofTokyo for examining the holotype of Cassidulina elegans
bosoensis. We also extend our thanks to Prof. I. Koizumi
of Hokkaido University, for the use of a low-vacuum SEM,HITACHI Natural SEM S-2250N, and to Mr. M. Hirama of
Hokkaido University for his photographic assistance.
This work was initiated during the period when one of
the authors (S.H.) was a faculty member of the Institute ofGeology and Paleontology, Tohoku University. S.
Hasegawa thanks Dr. Y. Takayanagi, Prof. Emeritus of
Tohoku University for his continuous encouragement.

Figures 4-5a-d
Cassidulina calabra (Seguenza). Brady, 1884, p.431, pI. 113,
figs. 8a-c; Bagg, 1912, p. 42, 43, pI. 12, figs. 1a-c; Chapman, 1926, p. 42, pI. 9, fig. 12.
Cassidulina pacifica Cushman, 1925, p.53, pI. 9, figs. 14-16 ;Earland, 1934, p.137, pI. 6, figs. 23-25; Asano and Nakamura, 1937, p.148, pI. 13, figs. 6a, b; LeRoy, 1941a, p.
42, pI. 1, figs. 43-45; LeRoy, 1964, p. F40, pI. 11, figs. 19,
20.
Cushmanulla pacifica (Cushman). Saidova, 1975, p. 336, pI.
88, figs. 11, 12, pI. 115, fig. 4.
Burseolina pacifica (Cushman). Nomura, 1983a, pI. 6, fig. 2 ;pI. 21, figs. 6-10; 1983b, p.57, pI. 5, figs. 1a, b, 2, 3a, b, 4.
Redescription of hypotype.- Test medium, compact,globular, Slightly longer than broad; periphery broadly
rounded, not lobulate; chambers distinct, elongate, notinflated, about five pairs making up last-formed whorl,
final chamber comprising about one-third of entire test in
front view; sutures distinct, limbate, slightly curved, notdepressed; aperture large, a bow-shaped narrow slit
extending up at an angle of about 70 degrees to suture atbase of apertural face, with a distinct apertural flap,

References cited

Asano, K., 1937: Foraminifera from the Setana group in
Hokkaido. Journal of the Geological Society ofJapan, vol. 44, no. 525, p.509-512. (in Japanese)
Asano, K., 1938a: Fossil foraminifera from the Miura
Peninsula. Contributions from the Institute of Geology and Paleontology, Tohoku Imperial University,
no. 31, p. 1-55, pI. 1. (in Japanese)
Asano, K., 1938b: Fossil foraminifera from the Boso
Peninsula. Contributions from the Institute of Geology and Paleontology, Tohoku Imperial UniverSity,
no. 31, p.57-96, pis. 6-9. (in Japanese)
Asano, K., 1938c: On some Pliocene foraminifera fromthe Setana beds, Hokkaido. Japanese Journal of
Geology and Geography, vol. 15, nos. 1-2, p.87-103,
pis. 9-11.
Asano, K., 1939: Report on the Recent foraminifera fromthe Urashima Bank, Wakasa Bay. Botany and Zoology, vol. 7, no. 10, p. 39-45, 4 text-figs. (inJapanese)
Asano, K., 1951: Illustrated Catalogue of Japanese Tertiary Smaller Foraminifera: Part 7, Cassidulinidae, p.1-

987.

Redescription of Asano and Nakamura's cassidulinids

7, 45 text-figs. Stach, L.W. ed., Hosokawa Printing
Company, Tokyo.
Asano, K. and Nakamura, M., 1937: On the Japanese
species of Cassidulina. Japanese Journal of Geology
and Geography, vol. 14, nos. 2-3, p.143-153, pis. 1314.
Bagg, A.M., 1912: Pliocene and Pleistocene foraminiferafrom southern California. United States Geological
Survey, Bulletin 513, p. 5-155, pis. 1-28.
Barker, R.W., 1960: Taxonomic notes on the species
figured by H.B. Brady in his report on the foraminifera
dredged by H.M.S. Challenger during the years 18731876. Society of Economic Paleontologists andMineralogists, Special Publication, no. 9, p.1-238, pI.
1-115.
Belford, D.J., 1966: Miocene and Pliocene smaller foraminifera from Papua and New Guinea. Bureau ofMineral Resources, Geology and Geophysics, Australia, Bulletin, no. 79, p. 1-306,25 text-figs., pis. 1-38.
Brady, H.B., 1884: Report on the foraminifera dredged by
H.M.S. "Challenger" during the years 1873-1876.
Reports on the Scientific Results of the Voyage of the
H.M.S. Challenger during the years 1873-1876, Zoology, vol. 9, p. 1-814, pis. 1-115.
Chapman, F., 1926: Cretaceous and Tertiary foraminifera
of New Zealand: With an appendix on the Ostracoda.
New Zealand Geological Survey, Paleontological
Bulletin 11, p.1-119, pis. 1-22.
Chiji, M. and Konda, I., 1970: Depth distribution of foraminiferal assemblages in the bottom sediments
around Okushiri Island, north Japan Sea. Bulletin of
the Osaka Museum of Natural History, no. 23, p.3550, pis. 7-10. (in Japanese with English abstract)
Cushman, J.A., 1922: The foraminifera of the Atlantic
Ocean: Pt. 3, Textulariidae. United States National
Museum, Bulletin 104, vol. 3, p.1-149, pis. 1-26.
Cushman, J.A., 1925: New species of Cassidulina fromthe Pacific. Contributions from the Cushman Laboratory for Foraminiferal Research, vol. 1, pt. 2, p. 36-38,
pI. 7.
Cushman, JA, Todd, A. and Post, A.J., 1954: Recent
foraminifera of the Marshall Islands. Professional
Papers U.S. Geological Survey, 260-H, p.319-384,
pis. 82-93.
Drooger, C.W., 1953: Miocene and Pleistocene foraminifera from Oranjestad, Aruba (Netherlands
Antilles). Contributions from the Cushman Laboratory for Foraminiferal Research, vol. 4, pt. 4, p. 116-147,
pis. 19-24.
Eade, J.V., 1967: New Zealand Recent foraminifera of thefamilies Islandiellidae and Cassidulinidae. New
Zealand Journal of Marine and Freshwater Research,
vol. 1, p.421-454.
Eade, J.V., 1969: Globocassidulina nipponensis, newname for Cassidulina orientale Cushman, 1925, preoccupied. Contributions from the Cushman Laboratory for Foraminiferal Research, vol. 20, pt. 2, p. 65-66,
pI. 13.
Earland, A., 1934: Foraminifera: Pt. III, The Falklands
sector of the Antarctic (excluding South Georgia).
Discovery Reports, vol. 10, p.1-208, pis. 1-10.
Ellis, B.F. and Messina, A.A., 1944 et seq.: Catalogue ofForaminifera. 45 vols. and supplement-vols. Amer-103

ican Museum of Natural History, New York.
Hasegawa, S., 1979: Foraminifera of the Himi Group,
Hokuriku Province, Central Japan. Science Reportsof the Tohoku University, Second Series (Geology),
vol. 49, no. 2, p.89-163, pis. 1-16.
Hasegawa, S., 1986: List of the foraminiferal species
described by Professor Kiyoshi Asano of Tohoku
University. In, Matoba, Y. and Kato, M. eds., Studies
on Cenozoic Benthic Foraminifera in Japan, p.157168. Akita University, Akita. (in Japanese)
Higuchi, Y., 1954: Fossil foraminifera from the Miyata
Formation, Miura Peninsula, Kanagawa Prefecture.
Journal of the Geological Society of Japan, vol. 60,
no. 703, p.138-144, pI. 3. (in Japanese with English
abstract)
Inoue, Y., 1989: Northwest Pacific foraminifera as
paleoenvironmental indicators. Science Reports of
the Institute of Geoscience, University of Tsukuba,
Section B =Geological Science, vol. 10, p. 57 -162, pis.
18-33.
Ishiwada, Y., 1950: Foraminiferal depth assemblages fromthe mouth of Toyama Bay: Study on Recent marine
sediments, no. 1. Bulletin of the Geological Surveyof Japan, vol. 1, no. 4, p.182-194, pI. 1. (in Japanesewith English abstract)
Ishiwada, Y., 1964: Benthonic foraminifera off the Pacificcoast of Japan referred to biostratigraphy of the
Kazusa Group. Geological Survey of Japan, Reports
no. 205, p. 1-45, pis. 1-8.
Kameyama, T., 1972: An application of quantitative
method for the analysis of fossil benthonic foraminiferal assemblage. Memoirs of the Faculty of
Science, Kyushu University, Series D, Geology, vol.
21, no. 2, p.177-205, pis. 25-32.
Kikuchi, Y., 1964: Biostratigraphy of the Neogene andQuaternary deposits based upon the smaller foraminifera in the southern Kanto region. Contributions from the Institute of Geology and Paleontology,
Tohoku University, no. 59, p.1-36, pis. 1-8. (inJapanese with English abstract)
Kuwano, Y., 1954: Notes on the genus Cassidulina andallied genera from Japan, II: Description of new
species of Cassidulina from the Pliocene of southern
Kuwanto region (2). Miscellaneous Reports of the
Research Institute for Natural Resources, no. 35, p.
33-36.
Kuwano, Y., 1962: Foraminiferal biocoenosis of the seasaround Japan: A survey of Pacific-side biocoenoses.
Miscellaneous Reports of the Research Institute for
Natural Resources, no. 58, p.116-138, pis. 14-24.
LeRoy, L.W., 1941a: Small foraminifera from the late
Tertiary of the Nederlands East Indies: Pt. 1, Small
foraminifera from the late Tertiary of the Sangkoelirang Bay area, East Borneo, Nederlands East Indies.
Colorado School of Mines, Quarterly, vol. 36, no. 1, p.
11-62, pis. 1-3.
LeRoy, L.W., 1941b: Small foraminifera from the late
Tertiary of the Nederlands East Indies: Pt. 2, Small
foraminifera from the late Tertiary of Siberoet Island,
off the west coast of Sumatra, Nederlands East
Indies. Colorado School of Mines, Quarterly, vol. 63,
no.1, p. 63-105, pis. 1-7.
LeRoy, L.W., 1964: Smaller foraminifera from the late

104

Shiro Hasegawa and Ritsuo Nomura

Tertiary of southern Okinawa. Professional Papers
U.S. Geological Survey, 454-F, p.1F-58F, pis. 1-16.
Loeblich, A. and Tappan, H., 1992: Present status offoraminiferal classification. In, Takayanagi, Y. andSaito, T. eds., Studies in Benthic Foraminifera, Benthos'90, Sendai, p.93-102. Tokai University Press,
Tokyo.
Matoba, Y., 1967: Younger Cenozoic foraminiferal
assemblages from the Choshi district, Chiba Prefecture. Science Reports of the Tohoku University,
Second Series (Geology), vol. 38, no. 2, p.221-263,
pis. 25-30.
Matsunaga, T., 1963: Benthonic smaller foraminifera fromthe oil fields of northern Japan. Science Reports of
the Tohoku University, Second Series (Geology), vol.
35, no. 2, p. 67-122, 4 figs., 21 tab., pis. 24-52.
McCulloch, Y., 1977: Quantitative Observations on
Recent Foraminiferal Tests, with Emphasis on the
Eastern Pacific, Parts 1-3. 1078 p., pis. 49-248, University of Southern California, Los Angeles.
Nomura, R., 1983a: Cassidulinidae (Foraminiferida) fromthe uppermost Cenozoic of Japan (Part 1). Science
Reports of the Tohoku University, Second Series(Geology), vol. 53, nO.1, p.1-101, pis. 1-25.
Nomura, R., 1983b: Cassidulinidae (Foraminiferida) fromthe uppermost Cenozoic of Japan (Part 2). Science
Reports of the Tohoku University, Second Series(Geology), vol. 54, no. 1, p. 1-93, pis. 1-6.
Parker, FL, 1964: Foraminifera from the experimental
Mohole Drilling near Guadalupe Island, Mexico. Journal of Paleontology, vol. 38, no. 4, p. 617-636, pis. 97102.
Poag, C.W., 1966: Paynes Hammock (Lower Miocene?)
foraminifera of Alabama and Mississippi. Micropaleontology, vol. 12, no. 4, p.393-440, pis. 1-9.
Saidova, Kh. M., 1975: Bentosnye Foraminifery Tikhogo
Okeana [Benthonic foraminifera of the Pacific
OceanJ, Parts 1-3. p.1-875, pis. 1-116, Institut
Okeanologii im P.P. Shirshova, Akademiya NaukSSSR. (in Russian)Serova, M. Ya., 1978: Stratigrafiya i foraminifery Neogena
Kamchatki [Stratigraphy and foraminifers of the
Neogene of Kamchatka]. Akademii Nauk SSSR,
Trudy, vol. 323, p. 1-142, pis. 1-20. (in Russian)Sidebottom, H., 1910: Two new species of Cassidulina.
Journal of the Quekett Microscopical Club, London,
England, Series 2, vol. 11, p.105-108. (fide Ellis andMessina, 1940 et seq.)
Takayanagi, Y. and Hasegawa, S., 1987: Checklist andBibliography of Post-Paleozoic Foraminifera Established by Japanese Workers, 1890-1986. 95 p., Institute of Geology and Paleontology, Tohoku University,
Sendai.
Takayanagi, Y., Sakai, T., Oda, M. and Hasegawa, S.,
1982: Micropaleontology of piston cores, Wake to
Tahiti. Geological Survey of Japan, Cruise Report,
no. 18, p.238-263.
Troitskaja, T.S., 1970: Usloviya obitaniya i raspredelenie
foraminifer v Yaponskom More (semeistva EIphidiidae, Cassidulinidae i Islandiellidae) [Environmental conditions and distribution of foraminifers in
the Japan Sea (Families Elphidiidae, Cassidulinidae
and Islandiellidae)]. In, Fursenko, A.V. ed., Obstchie
voprosy izucheniya mikrofauny Sibiri, dalinego vostoka i drugikh raionov. Instituta Geologii i Geofiziki,
Akademiya Nauk SSSR, Sibirskoe Otdelenie, Trudy,
vol. 71, p. 136-160, 8 pis.
Uchio, T., 1950: Microfossils. In, Kawai, K. et al., Natural
gas in the vicinity of Otaki, Chiba-ken. Journal of
the Japanese Association for Petroleum Technology,
vol. 15, no. 4, p.151-219, 25 text-figs. (in Japanesewith English abstract)
Uchio, T., 1951 : New species and genus of the foramini
fera of the Cenozoic formations in the middle part ofthe Boso Peninsula, Chiba-ken, Japan. Transactions and Proceedings of the Palaeontological Societyof Japan, New Series, no. 2, p. 33-42, pI. 3.
Uchio, T., 1960: Ecology of living benthonic foraminiferafrom the San Diego, California, area. Special Publications Cushman Foundation for Foraminiferal
Research, no. 5, p. 1-72, pis. 1-10.
Ujiie, H., 1990: Bathyal benthic foraminifera in a piston
core from east off the Miyako Islands, Ryukyu Island
Arc. Bulletin of the College of Science, University of
Ryukyus, no. 49, p. 1-60, pis. 1-32.
Voloshinova, N.A., 1952: Kassidulinidy [Cassidulinidae].
In, Voloshinova, NA and Dain, L.G., Iskopaemye
Foraminifery SSSR, Nonionidy, Kassidulinidy i Khilostomellidy [Fossil foraminifera of the USSR,
Nonionidae, Cassidulinidae and Chilostomellidae J.
Trudy Vsesoyuznogo Neftyanogo Nauchno-issledovatel'skogo Geologo-razvedochnogo Instituta (VN/GRI), New Series, no. 63, p. 79-103, pis. 1-4.
Yabe, H. and Hanzawa, S., 1925: G/obigerina ooze fromthe sea lying south of Okinawa-jima (The Riukiu
Islands). Japanese Journal of Geology and Geography, vol. 4, nos. 1-2, p.47-54.

Imakane ~~, Kajigaya iltfEl7~' Kamimiyata ...t'§EE, Kiwada :liHDEE, Kyoshito ;flirijj, Maruyama 1LLU, Mitsumata '::::'3<., Miyata '§EE, Nakazato r:plIl., Nojima ffJi!!;, Ofuna ::kJllf}, Omagari::kflll, Oshikiri :j:Ij31;J], Pirika ~fljfoJ, Sawane tRfN, Semata i!mX, Setana i!mWJ, Shichiba j{~, Takao
il1Iint, Urashima-sho 7ifl!lf;JiIt., Yabu~, Yazu (=Yatsu) ~$.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 178, pp. 105-121, 8 Figs., June 30, 1995

/988 / Surface water changes in the Ryukyu Trenchslope region, western margin of the North Pacificduring the last 320,000 years
XUEDONG XU and MOTOYOSHI ODA
Department of Earth Sciences, Kumamoto University, Kumamoto, 860 Japan
Received 18 October 1994; Revised manuscript accepted 22 May 1995
Abstract. Two piston cores taken from the Ryukyu Trench slope, western margin of the North
Pacific, contain a micropaleontologic record of the last 105,000 years (covering the period fromisotope Stage 5 to Stage 1) and 320,000 years (covering the period from Stage 8 to Stage 1), respectively. Planktic foraminiferal assemblages are examined to reconstruct the past surface waterconditions. The surface water during interglacial stages 5 and 7 was similar to the postglacialsituation, when the studied region was dominated by warmer waters associated with the Kuroshio
Current. During glacial stages 2, 3, 4, 6 and 8, the Kuroshio-related warm water was weaker;
alternatively the influence of the temperate water which currently occupies the northern part of theWestern North Pacific Central Water was stronger. In these glacial stages, the temperate water
affected this region more intensely than it does today. However, the polar front characterized by the
Oyashio Current has never attained this area during the last 320,000 years. During stages 2, 4 and6, the surface water was eutrophic; the primary productivity in DCM (deep chlorophyll maximum)
layer was probably enhanced during stages 2 and 8.
The sea surface temperature is estimated based on percentage frequency data of planktic
foraminifera, using transfer function FP12-E. The estimated paleo-SST are 27-29°C for summer
and 18-26°C for winter. As a result, glaCial-interglacial fluctuations of the estimated SST are 1-2°C
for summer and 4-5°C for winter; seasonal contrast during interglacials is similar to that of today andslightly greater during glacials. The decline of winter SST during glacial periods is believed to havebeen caused not only by the southward displacement of the temperate water mass, but also by the
upward transporting of the cooler water from the underlying water column.
Key words: Planktic foraminifera, surface water, glacial-interglacial, paleo-SST, upwelling, Western
North Pacific Central Water
Introduction
During the past ten years, many piston cores around the
Ryukyu Island Arc have been taken for paleoceanographic study. Some of these cores have been examined forbenthic foraminifera (Ujiie, 1991) and calcareous nannoplankton (Ahagon et al., 1993). The present study was
undertaken by the investigation on planktic foraminifera toreconstruct the aspects of the surface waters in thisregion during past glacial and interglacials.
Moore et al. (1980) reconstructed the sea surface temperature in the Pacific Ocean of 18,000 years B.P. They
proposed a greater southward penetration of the Oyashio
Current during the last glacial, but indicated that thesouthward extension needed closer study and verification.
Thompson (1977) pointed out that this subarctic cold
current reached the southernmost islands of Japan. On

the contrary, Ujiie (1991) assumed a different flow patternof the Kuroshio Current during the last glacial, in whichinstead of entering the East China Sea, this warm current
ran along the Pacific side of the Ryukyu Island Arc, whichis composed of a group of the southernmost islands ofJapan.
The purpose of the present paper is to (1) estimate thepaleo-sea surface temperatures, (2) discuss the changesof surface water masses, and (3) clarify the influence ofthe surface currents in the studied region during the last
320,000 years.
Geographic settings
The Ryukyu Island Arc extends approximately from Lat.
24°N to 31°N, and bounds the western margin of the North
Pacific. On the ocean side, the southern Ryukyu Island

Xuedong Xu and Motoyoshi Oda

106

t.'r

\:' 't.':' ' ' ! I':~'

EAST CHINA SEA

V28-304

RN87·PC4

WESTERN NORTH PACIFIC

Figure 1. Location map of the cores used (solid circles) and referred to (solid star) in this study.
arrows show the flow of the Kuroshio Current and its branches (after Nitani, 1972).

Table 1.

Stippled

Location, water depth and core length of the piston cores used and referred to in this study.

Core No.

Latitude

RN87-PC4
RN89-PC3
V28-304

23"50.2'N
25"20.TN
28"32'N

Longitude124"24.1'E
12T28.9'E
134"08'E

Water depth(m)Core length
(cm)

2,488
2,255
2,942

365
386

988.

Northwest Pacific surface water changes

Arc is seperated from the Ryukyu Trench by the Sakishima Deep-sea Terrace which deepens from 2,000 m to
4,000 m with a very rugged topography.
The two piston cores were taken by the RjV Nagasakimaru. One, core RN87 -PC4, was collected from thecentral part of the southern Sakishima Deep-sea Terrace,south of Ishigaki Island, and the other, core RN89-PC3,
from the outer edge of the terrace, northeast of M iyako
Island (Figure 1). Their location, water depth and core
length are listed in Table 1.
Hydrographic conditions
The Kuroshio (Figure 1), a warm western boundary
current, is the main surface current of the western Pacific.
It crosses the southernmost part of the Ryukyu Island Arc,
entering the East China Sea, flowing northeastwards
along the continental slope, and leaves the East China
Sea through the Tokara Strait (Nitani, 1972).
In the western North Pacific (Figure 2), the surface flowof a gyre consisting of North Equatorial, Kuroshio and its
extension, and North Pacific currents forms a large water107

body, named the Western North Pacific Central Water(Bradshaw, 1959). The water masses here have properties intermediate between the Subarctic water and theEquatorial water. The Western Pacific Central Water
was further divided into two water masses on the basisof the dominant assemblage of planktic foraminifera responding to the physical properties of the waters in eachregion (Thompson, 1981), namely transitional and subtropical (Figure 2). The transitional water mass (usually
between 25 and 35"N) develops with a distinctive biological character near the zone of convergence of the Kuroshio and Oyashio currents; farther south of the transitional water mass, a subtropical water mass (usually
between 15 and 25"N) develops north of the convergencezone of the North Equatorial Current and the Equatorial
Counter Current.
Two piston cores in this study are located at thewestern margin of the North Pacific, beneath the warm
Kuroshio Current (although not the current axis). As aresult, the modern surface water in the core region is
generally tropical-subtropical. Furthermore, since theanticyclonic waterflow in the North Pacific forms minor

SUBARCTIC PACIFIC WATER
45"N

30"N

)
'-- ~

CENTRAL WATER..

SUsrR,/_ _ _ OPICAl

'---

15"N

PACIFIC WATER

SOUTH PACIFIC
120"E

135"E

150'1:

165"E

165'W

150'W

Figure 2. Upper water masses in the Western Pacific (after Bradshaw, 1959). The Western North PacificCentral Water is further divided into "transitional" and "subtropical" (after Thompson, 1981). The two studied
cores are indicated by solid circles.

108

Xuedong Xu and Motoyoshi Oda

nutrient upwelling along the gyre margin (Thompson, 1981),
the core region is also characterized by slight upwelling.
Brief notes on lithology and chronology of the cores
The lithology of the two Gores has been described by
Ono et al. (1989) and Ono and Takagi (1991). The sediments are composed of hemipelagic silt and clay, and theremains of calcareous organisms not clearly showing theeffects of dissolution. A volcanic ash layer which was
identified as the Ata Tuff (Ujiie et al., 1991) is contained ata horizon of 321-324 cm in core RN87 -PC4 and 89-92 cm

RN89-PC3
Depth
(cm)o

in core RN89-PC3. A slightly bioturbated zone between
145 and 180 cm was recognized in core RN89-PC3.
The chronology of the two cores was based on isotope
stratigraphy, tephrochronology and calcareous nan noplanktonic control (Ahagon et al., 1993). The result is
adopted here in this paper. Moreover, a planktic foraminifera, pink-pigmented G/obigerinoides ruber, lastappeared at a horizon of 110-112 cm in core RN89-PC3.
The extinction of this species has been assigned at about
120 kyrs. B.P. around the isotope stage 5e/6 boundary(Thompson et al., 1979). The last appearance datum ofpink-pigmented G. ruber in this study is consistent witha180 vs PDe (%0)
Globigerinoides sacculifer

Age
-2.5
(Ka) 0 ..,----. +-......L.-"----'--::::::;II,a.....----1

50

RN87-PC4
Age(Ka) 0..,----,

a180 vs PDe (%0)
Globigerinoides sacculifer

-0.5

-1.5

-2.5

D,,"

20
Ata

100

100

--+40

150

- ---

-0-.....

:Do•" ,up.... 0

"'.

~<t7

200
200

60

250
".

80

300
Ata

100

Do __ . .

0

d

<0.

•

300

Figure 3. Lithology and chronology of the two studied cores. The arrow shows the last appearance
datum of pink-pigmented Globigerinoides ruber which became extinct in the Indo-Pacific region at 120 kyrs.B.
P. The LAD here coincides with the previous chronologie results based on isotope stratigraphy, tephrochronology and calcareous nannoplankton control (Ahagon et al., 1993).

a0
18

PDB (%0)

VS

RN89-PC3 Globigerinoides sacculifer

wintersummerFDX

seasonal contrast

1~

AGE(Ka) 0 I -0.,5

Dissolution Index

Estimated Sea Surface Temperature ('C )

50
co

OJ

9J
100~

\

0

~

~

\

z

•

~

/'

0

::+
:::J"
::E
CD
en
.-+
""CJ

~
(")

::;;

a·

..........

150

en

c

4-

~
(")

CD

::E

200-1

l

-I

•

1

~
.-+

~

J

S!l
(")

:T
~

:::J

!C

250

~

.---.:l7.........

"

4-a.

1/

~

CD

en

o

ID

a1Bo VS PDe (%0)
RN87-PC4 Globigerinoides sacculifer
-0.5
-1.5
-2.5 1

AGE(Ka) 0 I

Dissolution Index

Estimated Sea Surface Temperature (CC)winterFDX

seasonal contrast
1,,,,,.J

d*

"""".

0

-

40 ~

o

I'

.-

~

--

"""", """""

\

3

~

I

/

~

I'

~

..........

x

c

co

a.

0
to
X

:J
C

~

:J

a.
~
0
0
'<
0

...

60

80

I

100

"

..

\

en
2:
0
a.

/

,/
4-b.

Estimated paleo-sea surface temperature, seasonal contrast and dissolution index (FOX), compared with down core0' 18 0 fluctuations.
Figure 4-a. Estimated paleo-SST, seasonal contrast and FOX changes in core RN89-PC3.
Figure 4-b. Estimated paleo-SST, seasonal contrast and FOX changes in core RN8? -PC4.
Figure 4.

~

988.

Northwest Pacific surface water changes

III

the previous chronologic study of these cores. As aresult, core RN89-PC3 encompasses the last 320,000
years, while core RN87-PC4 represents the last 105,000
years (Figure 3). These ages give an average sedimentation rate of about 1.2 cm/1,000 yrs. in core RN89-PC3, and3.4 cm/1,000 yrs. in core RN87-PC4, respectively.

species. Moreover, different morphologic forms in
G/obigerinoides sacculifer (with/without sac) and Globorotalia truncatulinoides (sinistral/dextral) are counted independently for paleo-temperature computation.

Sampling method and taxonomic criterion

Berger (1970) demonstrated that dissolution can alterboth geographic and temperature information of planktic
foraminiferal faunas and may produce unreliablepaleoecological estimates downcore where this effect has
occurred. On the basis of the broken shells and fragments, as well as the calculated dissolution index, thedissolution effect was evaluated for each sample in thisstudy, although the two cores were collected from a water
depth of about 2,500 m, well above the lYSOCline.
Thompson (1981) indicated that in general deep-sea
sediments above the lysocline from the western Pacificshow increased fragmentation during interglacials due tointensified dissolution effects. However, such a glacial/interglacial contrast was not discernible in the present twocores. Fragmentation was observed in most samples;several in the top part of the cores were found very wellpreserved. Nevertheless, their occurrence seldom exhibited obvious decreases or increases.
The dissolution index (Berger, 1979) is calculated as

Samples of core RN89-PC3 were taken at 5 cm intervals, while those of core RN87-PC4 were taken at 10 cm
intervals. After being washed on a 0.063-mm sieve withtap water, the residues on the screen were dried. The
residues were then split with a microsplitter until anamount sufficient to yield a workable number of foraminiferal speCimens is obtained. The microsplitter aliquot was sieved through a 0.150-mm screen. More than
200 planktic foraminiferal specimens were then pickedfrom the coarser fractions for faunal analysis.
In the taxonomy of planktic foraminifera, criteria given
by Saito et a/. (1981) are basically accepted in the present
work. However, it is sometimes difficult to distinguish
Neogloboquadrina eggeri and Neogloboquadrina pachyderma, which are linked by Neogloboquadrina blowi
and Neogloboquadrina incompta. Here, the criterion ofThompson (1977) is adopted to distinguish the four

Dissolution effect

Table 2. Modern SST, estimated average SST, seasonal contrast, communality and FDX in theisotope stages included in the studied intervals. The stars indicate stages incompletely covered by coresamples.
Table 2-a. Data for core RN89-PC3.

RN89-PC3

ModernSST Cc)Estimated
SST Cc)Seasonal
contrast Cc)

Communality

FDX

Core Top
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
Stage 7
Stage 8'28/21.8

28.78/24.15
28.76/23.82
28.44/22.63
28.42/21.80
28.47/22.05
28.84/23.10
28.24/20.68
28.65/22.68
28.50/22.07

4.63
4.94
5.81
6.62
6.42
5.74
7.56
5.97
6.43

0.98
0.97
0.90
0.90
0.90
0.92
0.86
0,91
0.84

3.92
4.09
4.35
4.53
4.47
4.47
4.62
4.53
4.92

Table 2-b.

Data for core RN87 -PC4.

RN87-PC4

ModernSST CC)

Estimated
SST CC)

Seasonal
contrast Cc)

Communality

FDX

29.01/24.53
27.66/19.58
28.34/21.46
28.21/20.33
28.90/23.21

4.48
8.08
6.88
7.88
5.69

0.93
0.77
0.86
0.84
0.87

4.21
4.68
4.55
4.80
4.65

28.2/22.1
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5'N

Percentage-frequencies (%) of dominant species in core RN89-PC3

a1S0 vs PDB (%0)(6)

Globigerinoides sacculifer

(7)

(9)

x

c

CD

c-

o

::J
(0

X

c

III
::J

c~

0
......

250

~

300 •

r

~

~~.

,

•

5- a.

0
'<
0

en

:::T

~

~

~

~

....

0
cIII

Percentage-frequencies (%) of the dominant species in core RN87-PC4

0180 vs POB (%0)
G/obigerinoides saccu/ifer(Ka)o I

-0.5

-1 .5

(1)

(2)

(3)

(4)

(6)

(5)

o

-2.5

10

(8)

(10)

(9)

10

20

300

(11)
1

J'

20 I ..::'i':.:k .,,:,,'.

co
9J
(Xl

z

o

::+

40

::J'

~
CD

en

-0

OJ
::;;

()

o·

60

en
c

1ir
()

CD

~

80

~
()

::J'

OJ

::J

(Q

100

CD

./

en

5- b.
Figure 5 _ Relative abundances of the 11 dominant planktic foraminiferal species, compared with down - core 0' 18 0 fluctuations.
1= P. obliquiloculata, 2 = Gnt. glutinata , 3 = Gds. ruber , 4 = Gds. sacculifer, 5 = Gnl. aequilateralis , 6 = Grt. infiata, 7 = Grt. truncatulinoides , 8 = Gna. bulloides, 9 = Gna. falconensis , 10 = Ngd. eggeri, 11 = Ngd. pachyderma (dextral).
Fig. 5- a. Down - core frequencies in percent of the 11 dominant species in core RN89- PC3.
Fig. 5- b. Down - core frequencies in percent of the 11 dominant species in core RN87 - PC4.

w

Xuedong Xu and Motoyoshi Oda

114

follows: FDX='2.(RP;)/'2.P i, where Ri is the ranking of a
species i according to its resistance to dissolution; andPi is the percentage of species i in the sample. Usually,
intense dissolution is reflected by high FOX values. The
calculated index (Figure 4) slightly fluctuates throughout
the two cores. However, neither a similar nor a reversed
trend appears to be present between the dissolution andthe climatic oscillations.
One sample taken from 290-292 cm (estimated at about
90 ka) from core RN87 -PC4 seems to be severely affectedby dissolution, because a marked increase is seen in the
FOX value as well as in fragmentation. For this reason,
the faunal composition of this sample is not considered inpaleoenvironmental interpretations.
Estimated Paleo-SST

The transfer function technique originated by Imbrie andKipp (1971) has been widely employed to estimate paleoecologic parameters from microfossil datasets. The
planktic foraminiferal transfer function FP-12E, developedby Thompson (1981) for the western North Pacific, isadopted in this study to estimate the paleo-sea surface
temperature (SST).
The paleo-SST curves of the two studied cores areshown in Figure 4. Estimated summer and winter SST
values are all greater than 23 C and 14 C, respectively,
falling within the range of SST which FP-12E can accurately evaluate (Thompson, 1981). Moreover, the communality of each sample, which is the summation of thesquares of the individual factor loadings, is also calculated. A communality of 1.00 signifies that all of thesample variance has been computed. The average communalities of the samples in the two cores are 0.85 and
0.88, respectively. The square roots of the averagecommunalities indicate transfer function FP-12E canaccount for 92.3% and 94% of the total variance in theobserved faunal information. Even the value of thelowest communality among the core samples exceeds
0.7, which can account for more than 84% of the total
faunal information. Now that the six faunal assemblages
in FP-12E, identified by Q-mode factor analysis, accounted for 93% of the total surface calibration set variance,
the communalities of the core samples here are very high.
Therefore, FP-12E can be expected to provide proper
estimates of SST in the core region, with standard errorsof 1SC in summer and 2SC in winter.
As shown in Figure 4, the summer SST values fluctuatefrom 2TC to 29 C, while those of winter SST range from18 C to 26 C. The amplitude of variation of summer SST
is about 1-2 C and that of winter SST is 4-5 C, reaching amaximum of 7.6"C, between the glacials and the interglacials. Curves of the paleo-winter SST and the climatic fluctuations (represented by 0' 180 oscillations) arealmost parallel.
Seasonal contrast (the summer-winter difference intemperature) and the 0' 18 0 are also comparable (Figure 4).
The seasonal contrast is greater during glacial stages
than during interglacial stages (Table 2): it averages 4.5Q

Q

6 C, which is identical to the modern value during interglacials, and 6-8'C during glacials.
Thompson (1981) mentioned that the largest temperaturechange occurred in the temperate (transitional) region
between 30 and 40 N, where down-core estimates varied
as much as 5 C between glacials and interglacials; thesubtropical area, on the other hand showed no temperature shift throughout the past 150,000 years. Although
the two cores studied here are under tropical-subtropicalwater at present, the magnitude of glacial-interglacial
SST contrast grades up to those in the transitional region.
In addition, it is of interest to note that the surface waterin Stage 6 was as cold as or colder than the last glacial(stages 2, 3 and 4) period, while that in Stage 7 was aswarm as or warmer than the last interglacial (Stage 5)
period. Moreover, the winter SST revealed by the twocores indicates that during stages 2 and 4, the surface
water in the southern part of the studied region was colder
than that in the northern.
Q

Q

Q

Planktic foraminiferal assemblages
through the coresMore than 200 specimens of planktic foraminifera per
sample were picked from fractions coarser than 0.150 mm.
A total of 34 speCies, attributed to 13 genera, were recognized. Predominant species with maximum relative frequencies greater than 10% are: Pulleniatina obliquiloculata, G/obigerinoides ruber, G/obigerinoides sacculifer, G/obigerinella aequilateralis, G/obigerinita
glutinata, G/obigerina bulloides, G/obigerina falconensis,
Neogloboquadrina eggeri, Neogloboquadrina pachyderma(dextral), Globorotalia inflata and Globorotalia truncatulinoides. These species constitute more than 80% of
the faunal assemblages in every one of the core samples.
Down-core frequency changes of the predominant
species, compared with the oxygen isotope curves, areshown in Figure 5. The relative abundance of P. obliquiloculata, G. glutinata and G. ruber decreased in glacials and increased in interglacials. On the contrary, therelative abundance of G. bulloides and N. eggeri increased in glacials and decreased in interglacials. G.
inflata and G. truncatulinoides maintained their low abundance only during few warm periods and increased during
most of the studied interval, whereas N. pachyderma (d)increased remarkably in isotope stages 2 and 8. Thus, ingeneral, most of them show a similar or reverse trend tothe climatic changes.

Q

Q

Q

Q

Q

Brief notes on the predominant species and theiroccurrence in core top sample

Among the predominant species, P. obliquiloculata, G.
sacculifer, G. ruber, G. aequilateralis and G. glutinata aretropical-subtropical species (Be, 1977), Particularly, P.
obliquiloculata belongs to tropical waters, in which its
highest abundance occurs between 10 N and 10'S, a belt
which coincides generally with equatorial current systems. The relatively high occurrence of this species inQ

RN89-PC3

alBO

vs PDS (%0)
(RN89-PC3)-0.5(Ka)ol-1.5 -2.5':;::001

RN87-PC4

Percentage occurrences (%)
warm
50

70

temperate
0 10 2030

10nutrient
30
50

Estimated SST (0C)
winter summer
18 22 26 30
I ",w.Ii .I .! I'

Percentage occurrences (%)
warm
30

50

temperate70'--"'--""""--li-'·~"""

Estimated SST (0C)nutrient

0 10 2030 20
40
"
r·
•
':::::::':J.

wintersummer60 18 22 26 30
"
, I'
,

CD

50

~
z

o

~

100

::T

:z:

(t)

....en
"1J
OJ
:::;;
()

150

o·

en

c

~

()

(t)

200
7

:z:

OJ

~
()

::T

250

OJ

:::J

!O
(t)

8

en

300

Figure 6, Down-core frequency changes of the three categories, compared with estimated paleo-SST. "Warm" represents thewarm-water species P. obliquiloculata, Gnt. glutinata, Gds. ruber, Gds. sacculifer and Gnl. aequilateralis; 'Temperate" represents thetemperate-water species Grt. inflata and Grt. truncatulinoides; "Nutrient" represents the nutrient-favoring species (eutrophic coolwater fauna) Gna. bulloides, Gna. falconensis, Ndg. eggeri and Ngd. pachyderma (dextral).

V1

Xuedong Xu and Motoyoshi Oda

116

the studied area is believed to be due to the warm
Kuroshio Current. These five species together are considered as indicative of warm surface water.
G. inflata and G. truncatulinoides are mid-latitude
species. G. inflata is the only indigenous species of theTransition Zone which lies between the subtropical andsubpolar zones (Be, 1977). G. truncatulinoides is mostabundant in a narrow band extending across the North
Pacific from approximately 40 N to 20 N (Bradshaw, 1959).
These two species characterize temperate water in the
North Pacific.
G. bulloides is known to characterize upwelling situations regardless of its geographic position (Hemleben etal., 1989). Be (1977) also reported that G. bulloides
occurred not only predominantly in subpolar regions, butalso was commonly found in upwelling areas and boundary currents in low-latitude regions. N. eggeri is a tropical-subtropical species in active current systems, alongcontinental margins and upwellings. It is rare in thecentral oceanic regions far from landmasses. As aresult, all the areas where N. eggeri and G. bulloides
proliferate are characterized by high nutrient levels. G.
falconensis and N. pachyderma (dextral) are species
whose distribution patterns are poorly known because
many published data lumped them together with G. bulloides and N. eggeri, respectively. G. falconensis, which
is closely allied to G. bulloides in morphology, is thought
to have similar ecologic requirements, too (Be, 1977). In
core RN89-PC3, the abundance of these two species
showed perfectly identical changes, but in core RN87PC4, they did not match each other. As to N. pachyderma (dextral), it has been indicated that all living representatives of the genus Neogloboquadrina which feed exclusively on phytoplankton (Hemleben et al., 1989) belong to
one biogeographic cline (Srinivasan and Kennett, 1976).
In both of the cores, N. pachyderma (dextral) went up inpercentage only in periods when N. eggeri was abundant.
But it is not the case that whenever N. eggeri increased
in abundance, N. pachyderma (d) increased; instead it is
the case that when N. eggeri was abundant for a time, thepercentage of N. pachyderma (d) would increase in part ofthis period. Regardless of all the discrepancies
mentioned above, these species as a whole are assumed
to indicate eutrophic surface water conditions.
Summarizing the above, we consider the predominant
species to be three indicators representing the tropicalsubtropical warm water, the temperate (transitional) waterand eutrophic surface water conditions, respectively. P.
00obliquiloculata, G. glutinata, G. rUber, G. sacculifer and G.
aequilateralis are warm-water species; G. inflata and G.
truncatulinoides are temperate-water species; G. bulloides, G. falconensis, N. eggeri and N. pachyderma (dextral) are nutrient-favoring species. Summation of therelative abundance of the constituents in a certain environmental category gives the weight of this environment.
The faunal assemblage in the core top sample contains
all the predominant species, and is composed of 60%
tropical-subtropical species, less than 10% temperatewater dwellers, and 20% eutrophic-water favoring habitants. The occurrence of the predominant species in thecore top sample, which is identical to that in the modern
surface sediments taken from the same region corresponds to the current hydrographic condition, in which thecore region is mainly influenced by tropical-subtropicalwater, far from the influence of the temperate water, witha medium nutrient supply.
Relationship between down-core faunalchanges and paleo-SST

The correspondence between the core top faunalassemblage and the modern water mass condition suggests that the proportional change of the three categories
in a sample can indicate changes in the properties of thesurface water. In other words, the proportional change ofthe three categories in a sequence can be used to indicate the shift of warm or temperate water, and the nutrient
supply in this region. The down-core frequency changesof the predominant species as three indicators, comparedwith the SST curves, are shown in Figure 6.
The percentage occurrence curves of warm-water
species are generally parallel to the oxygen isotope
curves in both cores. This category maintained its frequency of about 60% (which appeared in the core top
sample) in stages 1,5 and 7. The percentage maxima of
the warm-water species occurring at Stage 1 and Stage 7
correspond to the maxima in estimated winter SST. The
highest winter SST occurred at both periods in postglacial
episode and in Stage 7, which was estimated at about
215,000 yrs. B.P.
In Core RN89-PC3, the eutrophic speCies and thetemperate water species appeared to change in accordance with each other. Both the categories decreased ininterglacial stages 1,5 and 7, and increased in glacial
stages 2, 3, 4, 6 and 8. The winter SST minimum occurred in Stage 6 when both the eutrophic and the temperate

Figure 7. Important species from the studied cores. 1. G/obigerina bulloides d'Orbigny (umbilical view), from
RN89-PC3, 4-6 cm. 2. G/obigerina falconensis Blow (umbilical view), from RN89-PC3, 30-32 cm. 3. G/obigerinoides
ruber (d'Orbigny) (umbilical view), from RN89-PC3, 10-12 cm. 4. G/obigerinoides sacculifer (Brady) with sack (umbilicalview), from RN89-PC3, 4-6 cm. 5. G/obigerinoides sacculifer (Brady) without sack (umbilical view), from RN89-PC3, 46 cm. 6. G/obigerinella aequilateralis (Brady) (equatorial view), from RN89-PC3, 50-52 cm. 7. Pulleniatina obliquiloculata (Parker and Jones) (spiral view), from RN89-PC3, 14-16 cm. 8. Globorotalia truncatulinoides (d'Orbigny)sinistral (umbilical view), from RN89-PC3, 104-106 cm. 9. Globorotalia truncatulinoides (d'Orbigny) dextral (umbilicalview), from RN89-PC3, 184-186 cm. 10. G/obigerinita glutinata (Egger) (umbilical view), from RN89-PC3, 260-262 cm.
11. Globorotalia inflata (d'Orbigny) (umbilical view), from RN89-PC3, 354-356 cm. All scale bars=100,um.

988.

Northwest Pacific surface water changes

11 7

Xuedong Xu and Motoyoshi Oda

118

water species were well developed.
In core RN87 -PC4, percentages of the eutrophic
species are notably greater in stages 2 and 4 than instages 1,3 and 5, while those of the temperate species
are more abundant in other stages than in Stage 1. The
winter SST minima of about 18'C occurred in glacial
stages 2 and 4 when the eutrophic species flourished.
Considering the three categories, namely, indicators of
the influence of Kuroshio, influence of temperate water,
and the level of nutrient supply, we conclude:
1. Nutrient level in surface water was higher during theglacial periods than during the interglacial periods.
2. The influence of temperate water was much stronger in most of the intervals during the last 320,000 years,
except the postglacial and some periods in stages 5 and

7.
3. The decline in winter SST during glacials could becorrelated with the influence of the temperate water and/or the eutrophic surface water condition.
4. Contrary to general expectations, the glacial winter
SST in the southern core was lower than that in thenorthern one, keeping up with the richer trend of theeutrophic fauna in the southern core.
5. The influence of Kuroshio in both stages 5 and 7
was similar to the present-day situation. Its influence
was weaker in the other stages compared with the present.
Discussion
1. During the winter of the glacials, southwardadvance of the polar front narrowed the zone between
subpolar and subtropical, compressing the Western
Pacific Central Water. The surface flow of the gyre wasintensified, the boundary current became more active andsurfce water primary productivity in the marginal region
should have been enhanced. Moreover, the southwardadvance of the polar front forced the transitional zone toshift southward, too. When the heavier and cooler temperate water occupied the upper water column, the stability of stratification could have been destroyed, with vertical mixing causing upwelling of deeper nutrient-enrichedwater. The surface water would have been, therefore,
eutrophicated.
Using abundance data from plankton tows and isotopic
composition data from samples taken in the western
Atlantic, Fairbanks and co-workers (Fairbanks and Wiebe,
1980; Fairbanks et al., 1982) have demonstrated thatspecies are vertically stratified within the photic zone.
The mixed layer waters are relatively oligotrophic,
compared to the underlying waters. In our study, theeutrophic fauna increased during glacial periods, but they

did not necessarily match mutually. For example, in core
RN89-PC3, G. bulloides and G. falconensis were more
prominent in stages 2, 3, 4 and 6, whereas N. eggeri andN. pachyderma (d) were more remarkable in stages 2 and
8. Since G. bulloides is believed to be a mixed layerdweller, the enhanced percentages of this species sugggest the mixed layer was eutrophicated during those
periods by active vertical mixing. As to the other two
species, it has been reported that the N. eggeri peaks inabundance precisely in zones of highest primary productivity and deep chlorophyll maximum (Fairbanks and coworkers); N. pachyderma (d) is most abundant when
production in the Deep Chlorophyll Maximum (DCM) layer
is at a maximum (Sautter and Thunell, 1991). Thus, theincreased percentages of these two species might suggest an enhanced sea surface primary productivity in the
DCM layer during stages 2 and 8. Coincidentally, Florisphaera profunda, a nannoplankton species living exclusively in the lower euphotic zone (Okada and Honjo, 1973)
and abundantly occurring under great water transparency(Tanaka, 1991), showed minimum relative frequencies instages 2 and 8 in the same core. Now that a reverse
relationship exists between F. profunda abundances andphytoplankton chlorophyll values in the Northwest Pacific(Ahagon et al., 1993), possible primary productivity enhancement in the DCM layer seems to be supported byevidence of nannoplankton as well.
2. The temperate water characterized by G. inflata andG. truncatulinoides influenced this region more powerfully
for most of the last 320,000 years. However, these two
species appeared to repel one another. G. inflata wasmore notable during stages 5 to 7, while the abundance ofG. truncatulinoides was greater during other periods. G.
inflata is a mixed-layer dweller (Fairbanks et al., 1980) andregarded as indicative of a well-mixed cool environment,
homothermal water column with intermediate nutrient
levels. On the other hand, G. truncatulinoides is believed
to be a very deep dwelling species (Tolderlund and Be,
1971; Hemleben et al., 1989; Lohmann and Schweitzer,
1990), at 600 m or >1,000 m. The flourishing of G. inflata
may require slight vertical mixing while that of G. truncatulinoides may require very deep stirring in the watercolumn. Therefore, they may reflect different propertiesof the central watermass, although both of them aretransitional water indicators.
3. During upwelling, the underlying subsurface water
which was brought upwards was not only more eutrophic,
but also colder. Therefore, the vertical movements of thewater in a water column could have depressed the SST,
as well as displacing horizontally the water masses.
Comparison of the two cores indicates that the temperatewater species were more abundant in the northern part of

Figure 8. Selected species of the genus Neogloboquadrina from the studied cores. 1a, b, c. Neogloboquadrina
eggeri (Rhumbler), from RN87-PC4, 80-82 cm. 1a: umbilical view, 1b: ·side view, 1c: spiral view. 2a, b, c. Neogloboquadrina blowi Rogi and Bolli, from RN87-PC4, 90-92 cm. 2a: umbilical view, 2b: side view, 2c: spiral view.
3a, b, c. Neogloboquadrina incompta (Cifelli), from RN87 -PC4, 50-52 cm. 3a: umbilical view, 3b: side view, 3c:spiral view. 4a, b, c. Neogloboquadrina pachyderma (Ehrenberg) dextral, from RN87-PC4, 60-62 cm. 4a: umbilicalview, 4b: side view, 4c: spiral view. All scale bars=100 j.lm.

988.

Northwest Pacific surface water changes

119

Xuedong Xu and Motoyoshi Oda

120

the studied region, while the eutrophic species were moreabundant in the southern part. This suggests that thenorthern part suffered much more temperate water while
the southern part witnessed vertical mixing more frequently. On one hand, the slightly higher proportion of temperate water species in the northern core RN89-PC3 might
have corresponded to the biogeography, in which thenorthern core was easily attained by the temperate water.
On the other hand, a slightly greater decrease in glacial
winter SST in the southern part implies that vertical mixing. of cooler water upwards might have contributed more to
the surface temperature's declining effect than did asouthward shift of the temperate water mass.
4. The strengthening of the temperate water in thecore region is the result of the southward advance of thepolar front. However, the polar front has never reached
the studied region during the last 320,000 yrs., since theunique species N. pachyderma (sinistral) which characterizes the Oyashio cold current (Takayanagi and Oda, 1984)
never occurred in any core sample. Thompson (1981)
mentioned the occurrence of sinistrally coiled N. pachyderma in Stage 6 in core V28-304 (Figure 1, Table 1)
which is located at Lat. 28'32'N. Hence the southernmost influence of the polar front might have reachedsomewhere between 30'N and 25'N (where northern core
RN89-PC3 is located) at Stage 6.
5. The warm-water species decreased in percentage
during the glacial periods. This does not necessarilyreflect the decline in influence of the Kuroshio Current
itself, for it may have been caused by the intensified
temperate water and the more active vertical mixing
during glacial periods. However, it is obviously not thecase that the main current of the Kuroshio swept acrossthe core region either. It appears that the last glacial
flow pattern of the Kuroshio proposed by Ujiie (1991) is notsupported by the planktic foraminiferal assemblages.
Under that hypothesis, the Kuroshio Current ran along theouter side of the Ryukyu Island Arc instead of entering theEast China Sea during the last glacial episode. If this istrue, the core region should have been under the maincurrent of the Kuroshio and the proportion of warm-water
species should have been much greater.
Conclusions

1. Notable dissolution effects changing in accordancewith glacial/interglacial alternations are not shown at thepresent 2,500 m-deep core site during the last 320,000
years.
2. The paleo-SST changes accord with the paleoclimatic oscillations. Summer SST slightly fluctuatedwithin 1-2'C, while winter SST was 4-5'C lower during
glacials than during interglacials. Maximum winter SSTof about 26'C occurred in Stage 7, while the minima of
about 18°C occurred in stages 4 and 6. The value ofseasonal contrast during interglacials was similar to themodern situation, but slightly higher during the glacials.
3. Conditions of the surface water during interglacial
stages 5 and 7 were similar to the present. The advanceof the polar front did not reach the studied area during thelast 320,000 years. Meanwhile, this region was not
dominated by the main current axis of the Kuroshio during
the glacials either.
4. The influence of the temperate water was stronger
in most of the studied intervals, particularly in glacials,
during the last 320,000 years than it is today.
5. Nutrient levels in surface water were higher during
all glacial stages than during interglacial stages. Verticalmixing was most prominent in glacial stages 2, 4 and 6.
Primary productivity in OCM layer was probably enhanced
during stages 2 and 8.
Acknowledgments

We are indebted to the officers and crew of the RjVNagasakimaru for their shipboard work. We express ourhearty thanks to Prof. Hiroshi Ujiie, University of the
Ryukyus, who kindly provided us the available piston coresamples. We are particularly grateful to Dr. Yokichi
Takayanagi, Professor Emeritus of Tohoku University,
who critically read through the manuscript and madeconstructive suggestions for revision. We thank thereviewers for their comments.
References cited

Ahagon, N., Tanaka, Y. and Ujiie, H., 1993: Florisphaera
profunda, a possible nannoplankton indicator of late
Quaternary changes in sea-water turbidity at thenorthwestern margin of the Pacific. Marine Micropaleontology, vol. 22, p.255-273.
Be, A.W.H., 1977: An ecological, zoogeographical andtaxonomic review of Recent planktonic foraminifera.
In, Ramsay, A.T.S. ed., Oceanic Micropaleontology, p.
1-100. Academic Press, San Diego.
Berger, W.H., 1970: Planktonic foraminifera: selective
solution and the lysocline. Marine Geology, vol. 8, p.
111-138.
Berger, W.H., 1979: Preservation of foraminifera. Foraminiferal Ecology and Paleoecology. SEPM Short
Course no. 6, p.105-155.
Bradshaw, J.S., 1959: Ecology of living planktonic foraminifera in the north and equatorial Pacific Ocean.
Contributions from the Cushman Foundation for Foraminiferal Research, vol. 10, p. 25-64.
Fairbanks, A.G. and Wiebe, P.H., 1980: Foraminifera andchlorophyll maximum: Vertical distribution, seasonal
succession, and paleoceanographic Significance.
SCience, vol. 209, p.1524-1525.
Fairbanks, R.G., Sverdlove, M., Free, R., Wiebe, P.H. and
Be, A.w.H., 1982: Vertical distribution and isotopic
fractionation of living planktonic foraminifera from thePanama Basin. Nature, vol. 298, p.841-844.
Hemleben, Ch., Spindler, M. and Anderson, O.A., 1989:
Modern Planktonic Foraminifera. 363 p. SpringerVerlag, New York.
Imbrie, J. and Kipp, N.G., 1971: A new micropaleontological method for quantitative paleoclimatology: Application to a late Pleistocene Caribbean core. In, Turekian, K.K. ed., The Late Cenozoic

988.

Northwest Pacific surface water changes

Glacial Ages, p.77-181. Yale University Press, London.
Lohmann, G.P. and Schweitzer, P.N., 1990: Globorotalia
truncatulinoides' growth and chemistry as probes ofthe past thermocline: 1. shell size. Paleoceanography, vol. 5, p.55-75.
Moore, T.C. Jr., Burckle, L.H., Geitzenauer, K., Luz, B.,
Molina-Cruz, A., Robertson, J.H., Sachs, H., Sancetta,
C., Thiede, J., Thompson, P.R. and Wenkam, C., 1980 :The reconstruction of sea surface temperatures in the
Pacific Ocean of 18,000 B.P. Marine Micropaleontology, vol. 5, p.215-247.
Nitani, H., 1972: Beginning of the Kuroshio. In, Stommel,
H. and Yoshida, K. ed." Kuroshio-Its Physical
Aspects, p.129-164. University of Tokyo Press,
Tokyo.
Okada, H. and Honjo, S., 1973: The distribution of oceanic coccolithophorids in the Pacific. Deep-Sea
Research, vol. 20, p.355-374.
Ono, T., Midorikawa, T., Yamamoto, S. and Ujiie, H., 1989 :Sediments taken from the sea-bottom around thesouthern Ryukyu Island Arc during the RN-84, 86
and -87 cruises. The Bulletin of the College of
Science, University of the Ryukyus, no. 47, p.115-151.
(in Japanese with English Abstract)
Ono, T. and Takagi, U., 1991 : Cruise reports of the RN-88~89 cruises around the southern Ryukyu Island Arc
and north of the Okinawa Islands, with special reference to the sediment samples. The Bulletin of theCollege of Science, University of the Ryukyus, no. 51,
p. 57 -85. (in Japanese with English Abstract)
Saito, T., Thompson, P.R. and Breger, D., 1981 : SystematiC
Index of Recent and Pleistocene Planktonic Foraminifera. 189 p. University of Tokyo Press, Tokyo.
Sautter, L.R. and Thunell, R.C., 1991: Seasonal variability
in the cS I8 0 and al3 C of planktonic foraminifera from121

the San Pedro Basin, southern California Bight.
Paleoceanography, vol. 6, p. 307-334.
Srinivasan, M.S. and Kennett, J.P., 1976: Evolution andphenotypic variation in the late Cenozoic Neogloboquadrina dutertrei plexus. In, Takayanagi, Y. andSaito, T. eds., Progress in Micropaleontology, p.329355. The American Museum of Natural History,
Micropaleontology Press, New York.
Takayanagi, Y. and Oda, M., 1984: Distribution of planktonic foraminifera in surface sediments of the
Pacific of northern Japan. Monthly Kaiyou-Kagaku,
vol. 15, no. 3, p.138-144. (in Japanese)
Tanaka, Y., 1991: Calcareous nannoplankton thanatocoenoses in surface sediments from seas around
Japan. Science Reports of the Tohoku University,
Second Series (Geology), vol. 61, p.127-198.
Thompson, P.R., 1977: Pleistocene and recent foraminifera of the western Pacific Ocean: biostratigraphy, dissolution and paleoecology. Doctoral thesis
for Tohoku University, Sendai, 475 p.
Thompson, P.R., 1981: Planktonic foraminifera in thewestern North Pacific during the past 150,000 years:
comparison of modern and fossil assemblages.
Palaeogeography, Palaeoclimatology, Palaeoecology,
vol. 35, p.241-279.
Thompson, P.R., Be, A.W.H., Duplessy, J.C. and Shackleton, N.J., 1979: Disappearance of pink-pigmented
Globigerinoides ruber at 120,000 yr B.P. in the Indianand Pacific Oceans. Nature, vol. 280, p.554-558.
Tolderlund, D.S. and Be, A.W.H., 1971 : Seasonal distribution of planktonic foraminifera in the western North
Atlantic. Micropaleontology, vol. 17, p.297-329.
Ujiie, H., Tanaka, Y. and Ono, T., 1991 : Late Quaternary
paleoceanographic record from the middle Ryukyu
Trench slope, Northwest Pacific. Marine Micropaleontology, vol. 18, p.115-128.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 178, pp. 122-141,13 Figs., June 30, 1995

Further observations of Cunninghamiostrobus
yubariensis Stopes and Fujii from the Upper Yezo
Group (Upper Cretaceous), Hokkaido, JapanTAMIKO OHANA and TATSUAKI KIMURA
Institute of Natural History, 24-14-3 Takada, Toshima-ku, Tokyo, 171 Japan
Received 25 October 1994; Accepted 22 May 1995

Abstract. Permineralized ovular conifer cones are common in occurrence in the Upper Yezo Group(Late Cretaceous in age) of marine origin, Hokkaido, Japan. This paper describes in detail ataxodiaceous ovular cone which is referable to those described originally by Stopes and Fujii (1910)
and later by Ogura (1930) under the name of Cunninghamiostrobus yubariensis Stopes and Fujii.
Unfortunately previous records did not show the ovular features in detail. However, we could study
these in our well preserved specimen. Ovules (or seeds) in this specimen are three in number oneach cone-scale, the only similarity between our cone and those of extant Cunninghamia. Vasculature in the cone-scale is different in the two. Comparison of the present cone with the otherCunninghamiostrobus cones and other allied cones hitherto described is also drawn in this paper.
Key words: Permineralized taxodiaceous cone, Cunninghamiostrobus, Upper Yezo Group, Late
Cretaceous, Hokkaido (Japan)
Introduction
The Upper Yezo Group of marine origin is extensively
exposed to the west of the meridional zone (nearly N-S
trend) of Hokkaido (see Ohana and Kimura, 1991, p.946).
This group has abundant calcareous nodules with fossil
plants and marine animals such as ammonites and inocerami indicating a Turonian-Coniacian-Santonian age forthe main part of the group. Although the fossil plants are
fragmentary and their organs mostly isolated in preservation, most of them are permineralized and their histological features are well preserved. Pioneering studies
on these were made by Stopes and Fujii (1910) and Ogura(1930, 1932).
Very recently we were fortunate to find a permineralized
taxodiaceous ovular cone among the collection made by
Hiroshi Takahashi from the upper course of the Obirashibe River, Tappu area (Ohana and Kimura, 1991, p.946)(roughly 44°04'N, 14f58.5'E). He very kindly gave it to us
for our study.
Stopes and Fujii (1910) originally described a permineralized taxodiaceous ovular cone obtained from the Yubariarea (Ohana and Kimura, 1993, p.42) under the name of
Cunninghamiostrobus yubariensis n. g., n. sp., but in theircone, ovules (or seeds) were not preserved.
Later Ogura (1930) described two similar permineralized
ovular cones collected also from the Yubari area under
the name of Cunninghamiostrobus yubariensis. However

in his cones, ovules (or seeds) were detached and not wellpreserved.
The present cone is very much more like those of
Cunninghamiostrobus yubariensis than any other ovularcones hitherto described. It has a well preserved coneaxis, cone-scales and ovules (or seeds) with their vasculature, and other histological details. This enabled us
to add to the descriptions of Cunninghamiostrobus yubariensis and to draw comparisons with those already known
and with extant Cunninghamia and also with other fossil
cones reputed to have Cunninghamia affinities.

Acknowledgments
We thank Dr. Shya Chitaley of the Cleveland Museumof Natural History, Ohio, U.S.A. for going over the language of the present manuscript, and Mr. Hiroshi Takahashi for gifting the cone specimen for the present study.
This study was supported in part by the Grant-in-Aid
from the Ministry of Education, Science and Culture (no.
04640725 given to Kimura and ~hana).

Description
Radial longitudinal section of the cone.-External surface of this cone can not be seen, because it iscompletely buried in rock matrix. Judging from its radial989.

Cunninghamiostrobus from Cretaceous of Hokkaido

Figure 1. Longitudinal sections of the ovular cone buried in the rock matrix. 1A. A nearly radial longitudinal section of the cone. Narrow gaps (a- b and c - d) show cutting losses (INH - 0014- 107). 1B. A nearlytangential (apical part) and radial longitudinal (proximal part) section cut along the a- b direction in Figure 1A(INH - 0014- 001). cs : cone scale, ov : ovule (or seed), pi : pith, rc : resin canal , st : scale trace, vs : vascular strand , xy: xylem cylinder. The cross section cut along the c - d direction in Figure 1A is shown in Figure
2B.

123

Tamiko Ohana and Tatsuaki Kimura

124

d

28

2A

lcm

I
I

a'

I
I
I
I

d'

Figure 2. Longitudinal and cross sections of the ovular cone. 2A. A brief sketch of the cone drawn from
Figure 1A. The line a- a' indicates the radial longitudinal section, the lines b- b', c - c' and d- d' indicate thetangential longitudinal sections, and the line e- e' (corresponding to the c - d gap in Figure 1A) indicates the
position of cross section respectively. 2B. A cross section cut along the e- e' direction in Figure 2A, showing
pith , xylem phloem cylinders and cortex in outward sequence, and radially and helically disposed scale traces(vascular strand in the cone scale) from the pith to each cone scale (INH - 0014- 012). cs: cone scale, co :cortex, ov : ovule (seed), ph : phloem cylinder, pi : pith, rc : r~sin canal , st : scale trace (see Figure 3A),
vs : vascular strand, xy : xylem cylinder.
Figure 3. Cross sections of cone axis and longitudinal sections of the xylem cylinder. 3A. A cross section of thecone axis, an enlarged part of Figure 2B. Two encircling rows of resin canals are recognizable in the cortex. No
annual ring is recognized in the xylem cylinder (INH - 0014- 012). 3B. A cross section of the boundary area between pithand xylem cylinder, showing the primary xylem tracheids surrounding the pith (INH - 0014- 012). 3C. A longitudinal
section of the xylem cylinder, an enlarged part of Figure 1A, showing pith cells and primary xylem tracheids, each withannular thickenings (INH- 0014-109). 3~. A longitudinal section, an enlarged part of Figure 1A, showing the primary
xylem tracheids with annular, spiral and scalariform thickenings, and the secondary xylem tracheids, each with a single
row of the bordered pits on the radial longitudinal section (INH- 0014- 109). co : cortex, ov : ovule (seed), ph: phloem
cylinder, pi : pith, px: primary xylem, rc : resin canal, st : scale trace, sx : secondary xylem, vs : vascular strand (incone scale), xy : xylem cylinder.

989.

125

Cunninghamiostrobus from Cretaceous of Hokkaido~----------~1500~m

500

~m

pi

.

px

sx

126

Tamiko Ohana and Tatsuaki Kimura

longitudinal section (Figures 1-2A), this looks cylindrical,
narrowing suddenly to a rounded apex. Proximal part ofthis cone is missing: the size may be more than 6.5 cm
long and up to 2.5 cm in diameter. Cone-scale complexes (we use the term 'cone-scale' or 'cone-scales' hereafter for short) are quite numerous, closely helical andattached at a wide angle or nearly perpendicular to a thickcone-axis, the angle reduced toward the apex. Their
precise phyllotaxy is uncertain.
Each cone-scale bears three ovules (or seeds) on its
adaxial surface (Figures 2B, 6C, 7A, 8, 11B, C).
Histological features.- The cone-axis has a pith, surrounded by xylem, phloem, cortex and cone-scales.
Cone-axis.-Cone-axis is thick, 9-11 mm in diameter,
narrowing gradually toward the apical portion where it is
5-6 mm in diameter (Figures 1,2, 3A).
Pith of cone-axis.-Pith is 2.2-3 mm in diameter, often
broken and disintegrated in part, consisting mainly ofparenchymatous cells and scattered sclerenchymatous
cells (Figures 1,2, 3A); the parenchymatous cells are
circular or polygonal in cross section, 20-40,um in diameter (Figure 3B), and are elongate-rectangular in longitudinal section, 50-120,um long (Figures 3C, D); the sclerenchymatous cells are filled with an opaque substance.
Xylem and phloem.-Xylem is picnoxylic and is 1.8-2.3
mm wide in cross section, surrounding the outer part ofthe pith (Figures 2B, 3). The primary xylem is endarch,
scattered at periphery of the pith (Figure 3B). Annular,
spiral and scalariform thickenings are seen on the walls of
primary xylem (protoxylem and metaxylem) tracheids (Figures 3C, D).
The secondary xylem tracheids are nearly square incross section, 10-20,um in diameter, larger on inner sideand smaller on outer side. No annual ring is observed(Figures 2B, 3A, B). Bordered pits are present on theradial walls of tracheids (Figures 3D, 4A). They are in
single or double rows, where they are oppositely arranged.
The medullary rays are single in a row and 2-11 cells
high (mostly 3-5 cells high) (Figure 4A). In a cross field,
two longitudinally disposed pores are seen (Figure 4A).
Tangentially elongated rectangular cells 4-5 cells thick
are recognized between the secondary xylem and phloem
cylinders (including cambium ?) (Figures 3A, 4A), but mostphloem cells are collapsed and it is difficult to recognize
the real boundary between phloem and cortex. The total
thickness of presumed phloem is about 1 mm.

Cortex and resin cana/s.-ln the cortex, resin canals arewell developed in two concentric rows (Figures 3A, 4B, E).
They tangentially surround the phloem. They are elliptical and tangentially elongated; inside ones are rather
smaller in diameter, 0.4-0.5 mm x 0.3 mm, outside ones
are 1-1.2 mm x 0.4-0.6 mm. The resin canals are linedwith tangentially flattened epithelial cells (Figure 4B).
Cone-scales.-ln sectional view, the boundary between
cone-axis and cone-scales is obscure, because thesurface of cone-axis is completely covered with thebases of cone-scales. Also the epidermis and thehypodermis of cone-axis were not visible. It is difficult torecognize cone-scale gaps. They appear to be readily
repaired, but a few gaps are seen at the apical portion of
the cone-axis (Figure 5E).
In each cone-scale, both ovular (or seed) and bract
scales appear to be completely fused together. Our
effort in this study to discern the boundary between thetwo by a fluorescence microscopy failed, because thesupposed boundary region in cross and longitudinal sections did not fluoresce.
Cone-scales are typically 10 mm long and 2-3 mm wideat the base of the cone (Figures 1,2, 4E, 6A, C, 7A, C-E, 8,
11A, C-E); in basal cross section, cone-scales are rhombic in form, 1.5 mm in vertical thickness. The width ofcone-scales increases toward the distal part of the cone,
reaching a maximum of about 7 mm at the distal twothirds of its length, then narrowing to the pointed apex;
apical region is not peltate. The views of serial crosssections of a cone-scale (Figure 8) vary from rhombic torhomboidal; in the apical two-thirds of a cone-scale, its
laterals are thin wing-like or membranous in cross section.
Cone-scale trace is single and originates from thexylem cylinder accompanying a small amount of pith
(Figures 4C, D), where it is circular or vertically elliptical incross section, about 0.7 mm in diameter (Figure 5C). In
this position, the pith is placed rather adaxially (Figure 5C).
Each trace enters the cone-scale as a cone-scale vascular strand. In this position the pith region is reduced insize (Figure 50). On its entering the cone-scale, a smallsized branch strand is separated adaxially from a main
strand, endarch primary xylem tracheids are present along
the periphery of the pith region and are eccentricallysurrounded by the secondary xylem tracheids (Figure 6B).
The phloem cells are mostly crushed. The slender ad ax-

Figure 4. Longitudinal section of the secondary xylem cylinder, cross section of resin canals and longitudinal
sections of scale traces and vascular strands in cone scale. 4A. A radial longitudinal section of the secondary xylem
tracheids and ray cells, an enlarged part of Figure 1A. An arrow indicates the cross field (INH-0014-109). 4B. A crosssection, enlarged part of Figure 28, showing xylem and phloem cylinders and cortex. Phloem cylinder is thin. An arrow
indicates a crushed cambial zone between xylem and phloem cylinders. Resin canals are lined by thin epithelial cells(INH-0014-012). 4C. A longitudinal section of the proximal portion of a scale trace consisting of its pith and xylem
cylinder, an enlarged part of Figure 1A (INH-0014-110). 40. Further enlarged section from the part indicated by an arrow
in Figure 4C (INH-0014-109). 4E. A longitudinal section, enlarged part of Figure 1A, showing the vascular strands
passing through the adaxial side of a cone scale and persisting to its tip. Arrows show the position of vascular strands(INH-0014-107). co: cortex, ov: ovule (seed), ph: phloem cylinder, pi: pith, px: primary xylem, rc: resin canal, xy:
xylem cylinder.

989. Cunninghamiostrobus from Cretaceous of Hokkaido

127

4A

500
IJm

.

co

ph

xy

500IJmrc

500IJm
i

40

{(
5mm

{(
{(

4C

128

Tamiko Ohana and Tatsuaki Kimura

ial strand is separated as a branch, then stands up andbecomes a vascular supply to the centrally located ovule(Figures 7B, 8, 9A). The eccentrically thick bundle isthen divided into trimerous branches which are extended
laterally in the cone-scale (Figures 60, 7A, B, 8).
Each lateral branch gives rise to a slender and shortovular branch near its proximal end (Figures 7A, B, 8).
Both branches stand up for a short distance and become
vascular supplies to the laterally disposed ovules (Figures
8,13A).
Each of the trimerous vascular strands is further divided
twice, also in a trimerous manner, on the same internal
plane, parallel to that of the cone-scale, and expands
flabellately, persisting to the apical part of cone-scale(Figures 8, 10C, 0, 11B, 13A).
The cone-scale consists histologically of epidermis,
hypodermis, transfusion tissue, ground tissue and resin
canals. The epidermis of both surfaces is represented bya single layer of thick-walled polygonal cells, 20-30 pm indiameter in surface view (Figures 120, E) and rather taller,
about 60 pm high in sectional view (Figures 12A-C).
Cuticle is not preserved.
Stomata are amphistomatic, restricted to the apical
one-fourth of cone-scale on both surfaces. They are
rather denser adaxially and absent on the narrow marginal
zones of cone-scale. The stoma is sunken and consistsof guard cells and 6-8 subsidiary cells (haplocheilic)(Figures 120, E). Aperture is randomly orientated (Figures
120, E) and stomatal complex is 70-80 pm in diameter insurface view.
Hypodermis appears to be restricted in distribution on
both surfaces of apical one-fourth of the cone-scale. In
alternation with the stomatal rows, it consists of a single
layer of cells adaxially and two layers abaxially (Figures
12C, F).
Transfusion tissue cells are present in alternation with
vascular strands at the apical region of cone-scales.
They are rather large in diameter (Figure 12F).
Ground tissue cells are mostly parenchymatous andhave the same features as those of the cortex of thecone-axis.
One to three resin canals of large diameter run into thecone-scale successively from the cortex in an abaxial
row, but at apical portion of the cone-scale, two disappear
and only one with the large diameter is discernible (Figure
8).

Ovules (seeds).- The ovules (seeds) are unexceptional-

Iy three in number on the adaxial surface of each conescale, flattened ovoid in form, typically 4 mm long, 1.6-1.8
mm wide and 0.6-0.8 mm thick. In sectional view threelayers of integument (seed coat) possibly corresponding tosarcotesta, sclerotesta and thin endotesta are discernible(Figures 7F, 9B, D), but their details are not well preserved.
The micropyle faces toward the cone-axis (Figures 9A,
B). Sometimes several longitudinal ridges are recognized on the surface of the ovules. These ridges are notso-called 'wings', but might have been caused by lateralpressure. The internal details of ovules (or seeds) are notwell preserved (Figures 7F, 9).
The mode of attachment and stability of ovules on thecone-scales appear to be unique. To recreate the formof the present cone-scale and ovules, we made a modelon the basis of serial cross sections (Figure 8).
In cross section of the cone scale, three lobed swellings
are discernible on adaxial surface of the cone-scale(Figure 110). Each swelling has a socket-like cavity facing the cone-axis. The base of the ovule is inserted in
the cavity to keep it stable (Figures 9A, C, 10B, 11A, C). In
addition there is a projection tissue of unknown function(placenta ?) at the bottom of the cavity (Figures 9A, C, 0,
10A, B). There is also a transverse ridge on the abaxial
surface of the cone-scale (Figures 8, 11A, E). The location of this ridge corresponds to the row of cavities on the
adaxial surface. This kind of ridge is good for keeping
ovules stable. The base of each ovule is asymmetricallyscooped out (Figures 90, 10B).
Discussion and comparison.- The present specimen is
the only one of a taxodiaceous ovular cone with numerous
cone-scales in close helix. Each cone-scale bears
three ovules (or seeds) on its adaxial surface. The
proximal part and peduncle of this cone are missing, andneither the corresponding vegetative shoot nor pollen
cone has been found so far.
Stopes and Fujii (1910) established the organ-genus
Cunninghamiostrobus and described C. yubariensis on thebasis of a single, detached and permineralized cone
without preserved ovules (or seeds). They did not write
about the preCise locality from which it came. According
to our recent knowledge, it could be true that this conecame from the Upper Yezo Group in the Yubari area. As
the original specimen of Cunninghamiostrobus yubariensis is obliquely buried mostly in the rock matrix, we can
not find out its size, and as all ovules (or seeds) are notedby them to be lost, we do not have the information about

Figure 5. Cross sections of scale traces in the xylem cylinder and outer cortex. SA. A typified tangential
longitudinal section of the xylem cylinder, showing the cross sections of fusiform scale traces helically disposed in thexylem cylinder, and the cross sections of circular (cut transversely) or elliptical (cut obliquely) vascular strands on theoutside of cortex. Phloem is shaded. 58. A longitudinal section of the xylem cylinder cut tangentially, showing thecross sections of fusiform scale traces; corresponding to the a-b-c-d cutting plane shown in Figure 5A (INH-0014-403).
5C. A cross section of the scale trace, an enlarged part of the Figure 58. An arrow indicates the position of the pith
(INH-0014-402). 50. Right side shows a longitudinal section cut tangentially on/near the outside of the cortex;
corresponding to the cutting plane b-e-f-c shown in Figure 5A. The x-y gap shows a cutting loss (INH-0014-403). 5E.
An apical longitudinal section of the cone cut tangentially, showing a slit consisting of pith cells which is considered
to be a leaf gap indicated by an arrow (INH-0014-403). co: cortex, ph: phloem cylinder, pi: pith, st: scale trace,
xy: xylem cylinder.

989.

Cunninghamiostrobus from Cretaceous of Hokkaido

129

5A

3mm

o o
f

o

58

o
o

ph

xy
st
5....,~O~mt - -_ _ _ _

5C

130

Tamiko Ohana and Tatsuaki Kimura

the number of ovules on each cone-scale. According to
Stopes and Fujii (1910), however, the histological featuresof their cone-axis and cone-scales were very close to
those of extant Cunninghamia, as their generic namesuggested.
Later, Ogura (1930) described his ovular cone, referring
it unwillingly to Cunninghamiostrobus yubariensis on thebasis of two permineralized ovular cones obtained fromthe Upper Yezo Group in the Yubari area.
First of all, we compare our specimen with those described by Stopes and Fujii (1910) and Ogura (1930) andalso with that of extant Cunninghamia.

Comparison with the cone described by Stopes and Fujii(1910)
1) Their cone is descr!bed as 2 cm x 3 cm in size which
is much smaller than ours. Our specimen is cylindrical,
2.5 cm in diameter and 6.5 cm in length. Possibly they
estimated its dimensions on the basis of the obliquely
exposed part only. 2) The V-shaped wing-like expansion as shown in their text-fig. 15A has not been found in
the cross section of our cone-scales. The wing-likeparts in ours are not V-shaped but laterally expanded. 3)
In their description and illustrations, the definition of their'pad' on the adaxial surface of cone-scale is not clear.
Similar swelling is also seen on the adaxial surface ofcentrally thickened part of each cone-scale in our specimen. However there are no ovules on their cone-scales
as is the case in ours. Cross section of our cone-scaleshows a projection of unknown function in each socketlike cavity of swelling, whereas they illustrated the presence of lateral edges of the 'pad' or 'ligule'-like extension
on the adaxial surface of their cone-scale. It is still
unclear whether this tissue represents a part of reduced
and connated ovular scale or not. In the present conescales, this tissue has not been found so far. 4) Resincanals (or resin ducts) are said to be numerous andirregularly distributed except for the main canal. But it ispossible that collapsed ground tissue cells might appear
like resin canals. They did not mention the presence ofepithelial cells lining the resin canal. 5) Ovular branchstrands courses were not described by them possibly
because of lack of serial sections. 6) The ovules are notattached to the adaxial surface of central 'pad' as they
presumed, but to the cavities in the swelling as mentioned
before in this paper. 7) They inferred that there were
three abortive ovules on an apical cone-scale. It is likelythat the process of ovular development and preservationof the original specimen are quite different from ours. In
the present cone, ovules are absent on a pair of apicalcone-scale, but on the other cone-scales ovules areunexceptionally present. 8) They mentioned that thestomata were distributed on the central part of conescales. However, in the present cone-scales stomata
are amphistomatic and restricted only to the apical part ofthe cone-scales. It is likely that an oblique section of
their cone might show only partly the stomatiferous apicalportion of the cone-scale.

Comparison with the cones described by Ogura (1930)
1) Ogura illustrated the presence of many scale gaps inhis sketch of cone-axis (his text-fig. 24), but we could notobserve any such gaps in his original section kept at the
University of Tokyo. According to our observation, thescale-gaps appear to be readily repaired by the xylem
tracheids. 2) A cross section of scale-trace is said to bevertically elongated fusiform with the pith in its center.
However, in our observation, the pith is located on theupper side (adaxial side) of the center. 3) In a cross-fieldof xylem tracheid, a single large and oblique pore is said
to be present, whereas in ours there are two verticalpores. In the case of poor preservation, it is highly
probable that two crushed pores are seen just as a single
one, and such a case is often visible in our cross-fields.
4) He mentioned that an ovular strand was separated at
the base of a main thick -strand, then bifurcated anddisappeared in the central part of a cone-scale. However, we could not find any such bifurcation of a central
ovular strand. The number of ovular strands ought to be
three on every cone-scale as mentioned before in thispaper. If the section was made fairly obliquely, then it islikely that it did not pass through all the three strands. 5)
He mentioned the presence of edges on the adaxial
surface of a cone-scale and he regarded them to be
margins of the possible ovular scale superposed on thebract scale. But in the present cone-scales, no mark or
trace indicating the presence of such ovular scale has
been observed.
Comparison with extant Cunninghamia
According to Satake (1934), ovular cones of Cunninghamia /anceo/ata Hooker are 3-4 cm in diameter and 4-5
cm long with cone-scales which are fan-shaped, withfinely serrate margins, which we could not observe in the

Figure 6. Cross sections of the proximal part of cone scales and vascular strand. 6A. A cross section of the conescales cut along the line b-b' in Figure 2A, showing rhombic cone scales, each with an adaxial thick vascular strand
and three abaxial resin canals (INH-0014-210). 68. A vascular strand, enlarged part of Figure 6A, showing an adaxial
ovular branch just separating from the vascular strand. Vascular strand is surrounded by the phloem cylinder; its
thickness is far thinner adaxially and fairly thicker abaxially (INH-0014-210). 6C. A cross section of the cone scales cut
between the lines b-b' and c-c' in Figure 2A, showing rhomboidal cone scales each with three ovules (seeds) on the
adaxial surface and three resin canals abaxially (INH-0014-301). 60. A vascular strand and an outer branch, anenlarged part of Figure 6C (indicated by an arrow). The vascular strand becomes flat and is about to separate into three.
This ovular branch is to be received by the central ovule (INH-0014-301). ob: ovular branch, ov: ovule (seed), ph:phloem cylinder, pi: pith, px: primary xylem, rc: resin canal.

989. Cunninghamiostrobus from Cretaceous of Hokkaido

131

u
(D

E

E

~--------------~I ('\")
E:::L~--------------~Ig

LO

132

Tamiko Ohana and Tatsuaki KimuraE~--------------------------~,~

E
::L
o
o
U")

989.

Cunninghamiostrobus from Cretaceous of Hokkaido

8N
~

~ ~8H

~

133

1l>z

rc
rc

8A

rc

•

~~I ~
<>
8e
8P
~~~
8J ~
<>
~=--80
~
8Q

88

80
~

~

~

8K

~

~

pc

pc

~

8E

8L

::::=:......--.

8G
Figure 8. Serial cross sections of a cone scale shown in alphabetic order. Figures 8A, 8G, 8H, 8J, 8R
and 8S were drawn from Figures 6A, 6C, 7A, 7C, 7D and 7E respectively. Slides: 8A = INH-0014-210, 88 =
-209, 8C= -208, 8D= -206, 8E=-204, 8F = -201, 8G = -301, 8H=-514, 81 = -511, 8J= -510, 8K= -509, 8L= -508,
8M = -507, 8N = -506, 80 = -505, 8P = -504, 80 = -503, 8R = -502 and 8S = -601. ov: ovule (seed), pc:
placenta (?), rc: resin canal, vs: vascular strand. For explanation of arrows, see Figure 11E.

Figure 7. Vascular strands, ovular branches, ovules (seeds) and resin canals. 7A. A cross section of the conescales cut along the line c-c' in Figure 2A, showing the branches of vascular strand in trimerous manner. Each lateral
strand sends further off an ovular branch reaching to each lateral ovule (INH-0014-513). 7B. Enlarged part of Figure 7A,
showing the two divided strands and an initial ovular branch indicated by arrow a and a lateral ovular branch indicatedby arrow b (INH-0014-513). 7C. A cross section of the cone scale cut between the lines c-c' and d-d' in Figure 2A,
showing three projections considered to be placentae in the central part of a cone scale (INH-0014-510). 70. A crosssection of the cone scale cut along a plane somewhat distant from and outside that of Figure 7C (outside of the ovular
attachment), showing the swelled central part and thinner lateral wings. Vascular strands are divided radially intrimerous manner in an adaxial paradermal plane of the cone scale. Resin canals are reduced in number to one at theabaxial center. The distinction of both ovular and bract scales is obscure or indistinguishable (INH-0014-502). 7E. A
cross section of the cone scale cut along somewhat inside the plane from the line d-d' in Figure 2A, showing bothbranched vascular strands and alternative transfusion tissues in a single adaxial row (INH-0014-502). 7F. A crosssection of an ovule (seed), showing an indefinite nucellus indicated by arrow a and three-layered integument (or seedcoat) indicated by arrow b (INH-0014-302). ob: ovular branch, ov: ovule, pc: placenta (?), rc: resin canal, vs:vascular strand.

134

Tamiko Ohana and Tatsuaki Kimura

present cone-scales. In that paper, Satake showed thevasculature of cone-scales in front and in serial sectionalviews as shown in Figure 138.
Satake's vasculature of extant Cunninghamia conescale differs considerably from ours as follows: 1) In theproximal cross section at point no. 1 in his fig. 3, thesectional view of a single vascular strand is quite different
from ours, where this strand is circular and its xylem isentirely surrounded by phloem (e.g. Figure 50). The
bundle in the extant species is rather an ellipse with alaterally elongated axis and its xylem and phloem arelocated at the adaxial and abaxial sides respectively. 2)
In the extant specimen the central ovular strand is said tobe dichotomously branched near its apex, but in ours, thecentral ovular bundle originates from the main bundle atthe proximal end of the cone-scale and does not branchthroughout (Figure 13A). If Satake's account is correct,
then we wonder about the position of the branches: Does
one of the branches run free or blind? 3) In Satake's
vasculature, each first branch runs obliquely, then bends
perpendicularly to the long axis of the cone-scale andgives off the second branches distally, which are parallelwith each other and also directed forward (Figure 13B). In
the vasculature of our specimen, the strands are branchedin a trimerous manner repeatedly and run nearly longitudinally, persisting to the apical part of the cone-scale. 4)
In the extant cone-scale, lateral ovules are said to receive
the vascular supplies separated from the first branches.
However in the present specimen they originate from thelateral branches of the first trimerous ones. 5) At theproximal end of the main scale strand, primary xylems are
said to be located adaxially, but in ours primary xylems arescattered around the pith which is located on the upperside of the bundle. 6) It was said that the sectional viewof cone-scales was obtriangular in form and lateral
membranous extensions were not visible, but in sectionalview of the present one, cone-scales are mostly rhombicrhomboidal and their lateral extensions are well developed. 7) Satake illustrated three lobed swellings at the
middle of the cone-scale and three small vestiges locatedon this side of lobed swelling respectively. He regarded
the former as ovular scale and the latter as placentae. In
the present cone-scale, the adaxial swelling with threesocket-like cavities may correspond to Satake's swelling,but it is unknown whether a projection seen in each cavity
corresponds to each placenta or not. In Satake's illustration of extant cone-scale, there are ligule-like free edges
in his cross section (his figs. 3-5). It is highly probablethat these edges seen in the cross section of cone-scale

represent the free parts of an ovular scale, but such edges
are not observed in the serial cross sections of thepresent cone-scale (e.g. Figure 8). From this comparison
it is evident that except for the presence of three ovules
on each scale, all the other features are different from thecone described in this paper. Although the present cone
does not agree fully with that of the extant Cunninghamia/anceo/ata Hooker, we would like to retain for our specimen the generic name of Cunninghamiostrobus established by Stopes and Fujii (1910). We are not aware of adirect systematic lineage between a Late Cretaceous
Cunninghamiostrobus and the extant Cunninghamia.
The present cone might be referable to those describedby Stopes and Fujii (1910) and Ogura (1930), collected fromthe same stratigraphical unit, the Upper Yezo Group of
Hokkaido, although the ovular features of the latter havenot been ascertained so far and some minor differences
are recognized between them. We are of the opinion thatthese minor differences may be attributed to the paucity ofhistological information in these earlier observations.
Therefore we give here an emended diagnosis of Cunninghamiostrobus yubariensis together with its systematic
position (see below).

Brief comparison with other permineralized Cunninghamiostrobus species and other allied fossils hitherto
described
Miller (1975) described Cunninghamiostrobus hueberi
from the Lower Cretaceous of California and Miller andCrabtree (1989) described C. goedertii from the Lower
Oligocene of Washington. In both species ovules (seeds)
are three in number on each ovular scale and the micropyle faces the cone axis. Besides the above, both
E/atides bommeri Harris and Spheno/epis kurriana (Dunker) Schenk described by Harris (1953) from the Lower
Cretaceous of Belgium might be comparable with thepresent species.
1) Cunninghamiostrobus hueberi was based on five
ovular cones of which one has its vegetative shoot in
organic connection. This species differs from the present species as follows: a) Cones are spherical or subelliptical, b) Presence of an annual ring is suggested in the
cross section of vascular cylinder of the cone axis, c)
Bordered pits seen on the radial section of tracheids arein two alternate rows, d) Ovular and bract scales arerather clearly recognized in the cone-scale, e) Resincanals are numerous, 8 in number in a bract scale except
at the tip of scale where it is single, f) Ovular scale isdivided into three at the tip, g) Ovules (seeds) are ellipti-

Figure 9. Ovules (seeds) and supposed placentae. 9A. A longitudinal section of the cone, enlarged part of Figure
1A, showing the vascular strands, ovules (seeds) with micropyle facing the cone axis, a central ovular branch and resin
canals (INH-0014-110). 98. A longitudinal section of the apical half of an ovule (seed), showing three indefinite layersof the integument (seed coat), supposed nucellus and a micropyle facing the cone axis (INH-0014-109). 9C. A
longitudinal section of the proximal portion of an ovule (seed), showing a central ovular branch and the supposed
placenta (INH-0014-110). 90. Ditto, Arrow a shows a part of the asymmetrically scooped base of an ovule (seed)detached from the supposed placenta indicated by arrow b (INH-0014-110). cs: cone scale, in: integument (seedcoat), mp: micropyle, nu: supposed nucellus, ob: central ovular branch, ov: ovule (seed), pc: supposed placenta,
rc: resin canal, vs: main vascular strand.

989. Cunninghamiostrobus from Cretaceous of Hokkaido

E
:I..
o
o

LO

E

:I..

o
o

LO

E
E

LO

:

.

-·<'
· -.., '.,.:'.A. .. · ~
...."

:

'.

.

.

-',

.' ~.

;..~ .

(~~~~~

135

Tamiko Ohana and Tatsuaki Kimura

136

500

IJm

......-------., 2mm

Figure 10. Cross section of ovular branch strands and paradermal section of the apical cone scale. 10A.
A cross section of the cone scale, showing an ovule, ovular branch strand, vascular strand and a supposed
placenta (INH - 0014- 509). 108. A cross section of the basal part of a detached ovule (seed), showing a
supposed placenta, ovular branch and a vascular strand (INH - 0014- 509). 10C. A nearly paradermal section ofan apical part of the cone scale, showing branched vascular strands in trimerous manner and resin canals (INH0014- 013). 100. Enlarged from the rectangular area in Figure 10C indicated by an arrow. cs : cone scale,ob : ovular branch , ov: ovule (seed), pc : supposed placenta, rc : resin canal, vs : vascular strand.

989.

Cunninghamiostrobus from Cretaceous of Hokkaido

a

pi

11A

ob

118

11E
ph
Figure 11. Vascular supplies, mode of attachment of ovules (seeds), form of cone scale and ovule (typified
sketches). 11A. A typical longitudinal section of the cone scale with the cone axis, showing a vascular strand,
resin canal, ovular branch strand and an ovule with supposed placenta and micropyle. The abaxial rib
indicated by arrow a in Figures 11A and 11E and the socket-like cavities at the inner side of swelling indicatedby arrow b in Figures 11A and 110, are considered to function to fix the ovules (seeds). 118. A cross sectionof the cone axis and a paradermal section of the cone scale, showing the branched vascular strands and ovules
attached to the adaxial surface of cone scale. 11C. An adaxial view of the cone scale and ovules. 110. An
adaxial view of the cone scale removing the ovules, showing the socket-like cavities (arrows b) on inner sideof swelling. 11E. An abaxial view of the cone scale with a transverse rib, and a longitudinal rib (arrow c)corresponding to the abaxial angles indicated by the arrows, such as in Figures SL, SR, SQ and SN. 11F.
Ovules (seeds) with asymmetrically scooped base. co: cortex, cs: cone scale, mp: micropyle, ob: ovular
branch, ov: ovule (seed), ph: phloem cylinder, pi: pith, rc: resin canal, sw: adaxial swelling, vs: vascularstrand, xy: xylem cylinder.

137

138

Tamiko Ohana and Tatsuaki Kimura

200,..m

Figure 12. Epidermis, hypodermis and transfusion tissue in the cone scale. 12A. A longitudinal sectionof the apical part of a cone scale, showing the epidermis consisting of taller cells. Stomatal complexes arerather closely distributed on adaxial surface of cone scale (INH - 0014-109). 12B. An enlarged part of Figure
12A. Guard cells are sunken and hypodermal cells are a single cell thick and devoid in distribution of stomatalrows. 12C. A sketch of stomata and hypodermal cells drawn partly from Figure 12B. 120. An adaxial
paradermal section of the apical part of cone scale, showing stomatal rows. The stomatal apertures areoriented randomly (INH- 0014- 013). 12E. A sketch of the stomatal complexes, drawn partly from Figure 12D.
Subsidiary cells are typically 7 in number per stoma. 12F. A cross section of the apical cone scale, showing
the branched vascular strands and alternate transfusion tissues, and the adaxial hypodermal layer of a single
cell thick and abaxial layers of two or more cells thick (INH - 0014- 601). ep : epidermis, gc : guard cell , hy :hypodermis, sc : subsidiary cell , tt : transfusion tissue, vs : vascular strand.

989.

Cunninghamiostrobus from Cretaceous of Hokkaido

13A
,

,I

I

,,

,

,~

..

139

, ,......

---

138

'.

,
\

I
\

I

,

\

\

I

,

\

I

,

I
I

,
,,

,,
,,

I

,

,,

\

I

\

\
\

,,

\

\

'. b

,

\

I

\

I

,
\

\

--,

-----

, "
,,

,

I

-,

\

I

I

I

,

,,

I

\

I
I
I

,,

I
\
\

,

\

I

I

\

,,

I

\
\
\

,

,

a

,

,,

I

I

,

,

I

,,

\

I

I

,

,

I

I

I

I

I
I
II

II

Figure 13. Difference of vasculature in the adaxial paradermal sections of cone scales between Cunninghamiostrobus yubariensis (Figure 13A) and extant Cunninghamia lanceo/ata (Figure 13B). 13A. A central
ovular branch strand (arrow a) is separated at/near the boundary region between cone axis and cone scale. A
single main vascular strand then divides into three. Each first lateral branch sends off a short ovular branch(arrow b) which is received by the lateral ovule. The main vascular strands are typically divided twice in atrimerous manner. Drawn on the basis of serial cross sections of a cone scale (Figure 8). 138. Vasculatureof the cone scale of extant Cunninghamia lanceo/ata Hooker (Satake, 1934). Arrow a' indicates a central ovular
branch strand of which the terminal part is dichotomously forked. A single main vascular strand is divided ina trimerous manner. Each first lateral branch sends off a short lateral ovular strand (arrow b'). The second
vascular strands are given off from the first vascular strands in parallel to each other and directed forwards;
the total number of secondary strands is 13-14.

cal in form with wing-like flanges laterally.
2) Cunninghamiostrobus goedertii was based on six
ovular cones. This species differs from the present
species as follows: a) Cones are spherical or elliptical,b) In cone-scale ovular and bract scales appear to be
separated and the former is represented by a small flap, c)
Resin canals are numerous, 5-15 in number in each bract
scale, d) Seeds are fairly large in size and flattened.
3) Elatides bommeri was based on leafy shoots withboth ovular and pollen cones preserved as compressions.
Its ovular cone differs from that of our specimen as
follows: a) Cones are considerably small in size, b)
Cone-scale consists of ovular and comparatively large
bract scales, each with a spine at the tip, 1 mm long and
0.3 mm wide, c) A single large-sized resin canal is present in a bract scale, d) Ovular scale is represented by a'ligule' with trifurcate tip, e) Seeds are 3-5 in number ineach cone-scale.
4) Sphenolepis kurriana was based on leafy shootswith ovular cones and has often been referred to in thecomparison of fossil taxodiaceous conifers. Its ovularcones have been compared by some authors with those of
Cunninghamiostrobus, but the former cones differ from thelatter in having six ovules on each cone-scale.
5) Recently such taxodiaceous ovular cones withoutpeltate scale-tip were described from the Upper Yezo
Group as Parataiwania nihongii (Nishida et al., 1992) and
Mikasastrobus hokkaidoensis (Saiki and Kimura, 1993).
Both species are distinguished from the present species
mainly by the number of ovules on each cone-scale: fourin Parataiwania and 4-5 in Mikasastrobus.
In this paper we mentioned that Cunninghamiostrobus
yubariensis is far apart from extant Cunninghamia espeCially in the vasculature and the number and arrangementof resin canals in the cone-scale, except for having threeovules on each scale.
It appears that the taxodiaceous conifers were at theculmination of their development in Late Cretaceous time.

Tamiko Ohana and Tatsuaki Kimura

140

To our knowledge they appear to have been much diversified during that period. The extant taxodiaceous conifers are thought to be restricted decendants, although at
present we can not explicate fully the direct systematic
lineages and the transition from the Late Cretaceous
taxodiaceous conifers to the present-day ones.

Systematics
Gymnosperms
Con iferophyta
Coniferales
Taxodiaceae
Organ-genus Cunninghamiostrobus Stopes
and Fujii, 1910
Emended generic diagnosis.-Cone scales and axis in
structure like those of the living genus Cunninghamia.
Cone taxodiaceous ovular. Cone-scale not peltate, but
in close helicals, bearing three ovules (seeds) on eachadaxial surface. Micropyle facing the cone axis. Histological features of the cone axis and cone scale rather
more similar to those of the extant Cunninghamia than toany other extant taxodiaceous genera.

Cunninghamiostrobus yubariensis Stopes
and Fujii, 1910. emend.
Figures 1-13A
Specimen.-Lectotype: INH-0014 (peel-slides; 001,
002,011-014,102-110,201-211,301-303,401-403,501-514,
601). All are kept in the Institute of Natural History,
Tokyo.
Locality and horizon. - Present specimen: KamiKinenbetsu Valley, Tappu, Obira-cho, Rumoi-gun, Hokkaido (roughly 44°04'N and 141°58.5'E). Upper Yezo
Group (Turonian) (collected by Hiroshi Takahashi).
Occurrence.-A single ovuliferous cone buried in a
calcareous nodule was collected.
Emended diagnosis.-Cone ovular, cylindrical, morethan 6.5 cm long and up to 2.5 cm in diameter. Cone axis
thick, 9-11 mm in diameter, with many helically arranged
cone-scale complexes, at a wide angle or nearly perpendicular. Cone-scale flattened and expanded laterally in
its apical half. Ovular and bract scales completely
adherent. Cone axis consisting of pith, xylem andphloem cylinders and cortex. Pith consisting mainly ofparenchymatous cells. Primary xylem endarch and secondary xylem without annual rings and with bordered pits
in one or two row opposite. Ray a single row 2-11 cells
high. Resin canals in two concentric cylinders in thecortex and outer ones continuing into the cone-scale. A
thick and eccentric vascular strand separating from thexylem cylinder and entering into the cone-scale, thestrand giving adaxially a slender ovular branch, connecting with the central ovule. The vascular strand branching twice or thrice in trimerous manner. The first lateralbranches giving short ovular branches to the lateralovules. Resin canals abaxial, three; lateral two
disappearing in apical half of the cone-scale. Transfusion tissue present at the apical part of cone-scalealternating with branched vascular strands. Ovules three
on the adaxial surface of a cone-scale. The bases ofovules fixed by the socket-like cavities on an adaxial
swelling. An abaxial transverse ridge present also helpful for fixing the ovules. Ovules (seeds) flattened elliptical, about 4 mm long, 1.6-1.8 mm wide and 0.6-0.8 mm
thick, without wing-like flange and with asymmetricallyscooped base. Integuments (seed coats) consisting of
three layers, and the micropyle facing the cone axis.
Epidermis covering whole surface of the cone-scale andhypodermis present in the apical part, a single layer
adaxially and two layers abaxially, devoid of stomatalrows. Stomata amphistomatic in the apical part, haplocheilic, sunken and randomly orientated. Vegetative
shoot and male cone not known.

References cited
Harris, T.M., 1953: Conifers of the Taxodiaceae from theWealden formation of Belgium. Institut Royal desSciences Naturelles de Belgique, Memoire, no. 126, p.
1-43, pis. 1-8.
Miller, C.N. Jr., 1975: Petrified cones and needle-bearing
twigs of a new taxodiaceous conifer from the Early
Cretaceous of California. American Journal of Botany, vol. 62, no. 7, p.706-713.
Miller, C.N. Jr. and Crabtree, D.R., 1989: A new taxodiaceous seed cone from the Oligocene of Washington. American Journal of Botany, vol. 76, no.1, p.
133-142.
Nishida, M., Osawa, T. and Nishida, H., 1992: Structure
and affinities of the petrified plants from theCretaceous of Northern Japan and Saghalien. VIII.
Parataiwania nihongii gen. et sp. nov., a taxodiaceouscone from the Upper Cretaceous of Hokkaido. Journal of Japanese Botany, vol. 67, p.1-9.
Ogura, Y., 1930: On the structure and affinities of some
Cretaceous plants from Hokkaido. Journal of theFaculty of Science, Imperial University of Tokyo, III,
vol. 2, pt. 5, p. 381-412, pis. 18-21.
Ogura, Y., 1932: On the structure and affinities of some
Cretaceous plants from Hokkaido. Second contribution. Journal of the Faculty of Science, Imperial
University of Tokyo, III, vol. 2, pt. 7, p.455-483, pis.
22-24.
Ohana, T. and Kimura, T., 1991: Permineralized Otozamites leaves (Bennettitales) from the Upper
Cretaceous of Hokkaido, Japan. Transactions andProceedings of the Palaeontological Society of Japan,
New Series, no. 164, p.944-963.
Ohana, T. and Kimura, T., 1993: Permineralized Brachyphyllum leafy branches from the Upper Yezo Group(Coniacian-Santonian), Hokkaido, Japan. Bulletin of
the National Science Museum, Tokyo, Series. C, vol.
19, no. 2, p.41-64.
Saiki, K.and Kimura, T., 1993: Permineralized taxodiaceous seed cones from the Upper Cretaceous of
Hokkaido, Japan. Review of Palaeobotany and989.

Cunninghamiostrobus from Cretaceous of Hokkaido

Palynology, Elsevier, vol. 76, p. 83-96.
Satake, Y., 1934: On the systematic importance of thevascular course in the cone scales of the Japanese
Taxodiaceae (Preliminary report). Botanical Magazine, Tokyo, vol. 48, p.186-205. (in Japanese with

141

English resume)
Stopes, M.C. and Fujii, K., 1910: Studies on the structure
and affinities of Cretaceous plants. PhilosophicalTransactions of the Royal Society of London, Series
B, vol. 201, p. 1-90, pis. 1-9.

Hokkaido ~t#ltJ!l:, Kami-Kinenbetsu J:.~c~5JU, Obira IJ\.:ljZ, Obirashibe IJ\.:ljZ~, Tappu it;ffi", Yubari)7~, Yezo ~~.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 178, pp. 142-153,8 Figs., June 30, 1995

1

990

1

Inoceramus (Platyceramus) szaszi sp. nov.
(Bivalvia) from the Coniacian (Cretaceous) of
Hokkaido

MASAYUKI NODA and SHIGEHIRO UCHIDA
Fukagochi 5 kumi, Oita, 870 Japan
Ochanomizu 176, Iwamizawa, 069-03 Japan

Received 21 November 1994; Revised manuscript accepted 22 May 1995
Abstract. Inoceramus (Platyceramus) szaszi sp. nov. is established on a sample and supplementary
specimens from the upper Middle Coniacian of the Ikushunbetsu valley, central Hokkaido. It resembles I. (PI.) mantelli de Mercey, 1877 and also I. (PI.) troegeri Noda, 1992, but is distinct from themin its fan-shaped outline, fairly constant obliquity and inconspicuous ornamentation. Statisticalanalyses of some selected characters also reveal significant morphological differences. On the
ground of stratigraphic position and morphological resemblance, I. (PI.) szaszi is presumed todescend from I. (PI.) troegeri of the Lower to lower Middle Coniacian, but it is probably an offshootwithout giving rise to any descendant.
Key words: Inoceramus (Platyceramus), Coniacian, biometry, phylogeny

Introduction

The area of the Ikushunbetsu River, including its tributary the Ponbetsu, is celebrated as a classical field ofCretaceous stratigraphy and paleontology.
The speCimens for this study were previously included
in Inoceramus (Platyceramus) yubariensis Nagao andMatsumoto by Noda (1986). At the suggestion of T.
Matsumoto, I. yubariensis was restudied by Noda andToshimitsu (1990) and has proved to be a junior synonymof I (Platyceramus) mantelli de Mercey. In the course ofthat study, a sample from the locality Ik2709 of thePonbetsu area has been morphologically discriminatedfrom other samples. This paper gives the result of ourstudy of this sample.
Note on stratigraphy

The specimens examined were obtained from a calcareous nodule in the sandy siltstone exposed in the upper
reaches of the Ponbetsu-gono-sawa (sometimes called
the Takino-sawa or Takiyoshi-zawa), a tributary of thePonbetsu River, where the Cretaceous deposits of theupper part of the Yezo Group are partly exposed, as
described by Matsumoto (1984) and Matsumoto and Noda
(1985). We redescribe, herein, the stratigraphic sequence
after Matsumoto (1984) with additional information, showing a route map in Figure 1.

The Coniacian strata are well exposed along the creek.
Owing to lateral change, the green sandstone at the baseof the Coniacian is thinner and more silty than in theoutcrops to the east (Matsumoto, 1984, figs. 2, 3). The
main part is fine sandy siltstone with a more sandy part in
the middle of the Coniacian. Due to NW-SE wrench
faults and an anticline, the sequence is observable
repeatedly. Throughout this seqence inoceramids occur
commonly and successively and are associated withsome ammonites. The Coniacian Stage can be divided
into three parts in this section. The lower part, represented by Ik2726a, b, 2716, 2717, 2710a-k, 2785 and 2786,
contains Inoceramus (Cremnoceramus) rotundatus Fiege(common), I. (I.) uwajimensis Yehara (few), Didymotis
akamatsui (Yehara), Anagaudryceras lima tum (Yabe), Forresteria (Reesideoceras) petrocoriensis (Coquand), F. (R.)
sp. and F. (Harleites) cf. harlei (de Grossouvre) (rare). The
middle part, represented by Ik2726c, 2725, 2713, 27101, m,
2709 and 2748, is characterized by the abundant occurrence of I. (I.) uwajimensis. Associated fossils are F.
(Forresteria) alluaudi (Boule, Lemoine and Thevenin),
Barroisiceras (Baseoceras) inornatum Matsumoto andKossmaticeras theobaldianum (Stoliczka). I. (PI.) szaszi
sp. nov. was found by S. Uchida from Ik2709. The sandy
siltstone at loc. Ik2709, which we allocate to the upper
portion of the middle part, yields I. (I.) uwajimensis abundantly and I. (Cordiceramus) kawashitai Noda andI. (Cremnoceramus) mihoensis Matsumoto rarely. The

990.

Inoceramus from Coniacian of Hokkaido
N

!

I

I

>

t

TERTIARY2703 ................. .

A

143~::~.;.~.~2702'ff"

SANTON IAN

J

I

.

I

>

B

\

2713· ..................

100m

C

........ 27090...... 2710

E\

TURONIAN

F............ · .. ·2718

2719 .. ·· ..

G---t-o .- l-I
2724 ..

_.-._ .. - . -CONIACIAN---------.

=

J............ ·2725

SANTONIAN.' .. \.
• la,lmar-__~f_·~_._._._._ .

..... .....

2799·

CONIACIAN..... .....
. TURONIAN

K

Is

lu,lmh,lk-]"""'2709

TURONIAN

•

lu

4It

•

.......... 2787•.......... ·2786

If, Oi•2785-"
2784· ........ ·

\

I

!

!

!

f

I

I

\

.] Fp·: If, Oif

CONIACIAN....,..,....1" \TURONIAN
10m

I. . . I..··

J

J

•

,.....'7'--~~>,' '-"\
Figure 1. Route map along the Ponbetsu-gono-sawa, with stratigraphic profile. Locality number shouldhave prefix Ik. Legend for profile and map, A: fine-grained sandy siltstone, B: fine-grained silty sandstone,
C: thick-bedded sandstone, D: tuff, E: unconformity, F: fault (observed), G: fault (inferred), H: anticline, I:
stage boundary, J: path (partly damaged), K: debris barrier. Abbreviation of selected species, la : Inoceramus (I.) amakusensis, Ima: I. (Platyceramus) mantelli, Imh: I. (Cremnoceramus) mihoensis, Ik: I. (Cordiceramus) kawashitai, Is: I. (PI.) szaszi, lu: I. (I.) uwajimensis, Ir: I. (Cr.) rotundatus, It: I. (I.) teshioensis and I. (I.)
tenuistriatus, Oi: Oidymotis akamatsui, Fp: Forresteria (Reesideoceras) petrocoriensis, Lp: Lymaniceras
planula tum.

Masayuki Noda and Shigehiro Uchida

144

upper part, represented by Ik2708,2705 and 2724, ischaracterized by I. (Cr.) mihoensis, I. (Co.) kawashitai and
I. (PI.) mantel/i.

Another specimen was obtained as a float in a branchof the Kumaoi - zawa, which is a tributary of the uppercourse of the Ikushunbetsu River, where the Coniacian
sediments are exposed, showing gradually higher parts ofsequence eastwards along the creek.

Type species. - Inoceramus mantel/i de Mercey, 1877by original designation (Seitz, 1961, p. 54, ex Heinz, 1932,
p. 10).
Remarks .- For the diagnosis and affinities of this subgenus, see Seitz (1961 , p. 54) and Noda (1983, p. 202 ;1992, p. 1314).

Inoceramus (Platyceramus) szaszi Noda
and Uchida sp. nov.

Systematic description

Figures 2, 3, 5

Family Inoceramidae Zittel, 1881

Inoceramus (Platyceramus) yubariensis Nagao and Matsumoto.
Noda, 1986 (part), p. 363, listed.

Genus Inoceramus Sowerby, 1841
Subgenus Platyceramus Seitz, 1961

Types. - Holotype: JG. H2901 obtained by Uchida at
loc. Ik2709, from the sandy siltstone in the upper Middle

Figure 2. Inoceramus (Platyceramus) szaszi Noda and Uchida sp. nov. All figures natural size. 1a- c. JG.
H2909, paratype, from lac. Ik 2709. 2a, b. JG. H2794, paratype, same locality. 3 . JG. H3099a and b,paratypes, from loc. Ik 1623p, a tributary of the Kumaoi - zawa. 4. JG. H2903, paratype, from loc. Ik2709.

990. Inoceramus from Coniacian of Hokkaido

Figure 3. Inoceramus (Platyceramus) szaszi Noda and Uchida sp. nov. All figures natural size. 1a- d. JG.
H2901, holotype, from loc. Ik2709, Ponbetsu - gono- sawa. 2a - c. JG. H2903, paratype, same locality.

145

Masayuki Noda and Shigehiro Uchida

146

Coniacian in the Ponbetsu-gono-sawa. Paratypes: JG.
H2794, 2898, 2903 and 2909, obtained from the same
nodule as the holotype. JG. H3099a and 3099b are
floats collected at loc. Ik1623 in a branch of the Kumaoizawa, originating probably from the Coniacian mudstone
exposed along the upper reaches of the creek.
Repository.-JG.: Jonan Geological Association, kept
tentatively in Noda's personal laboratory, Oita.
Diagnosis.-Shell medium to large, equivalve, gently
and uniformly inflated, fan-shaped in outline and slightly
higher than long. Umbo small and terminal. Shell ornamentation weak; concentric undulations developed inlater stages of growth, low and irregular in breadth, withsuperimposed minor rings.
Species name.-This species is dedicated to Dr. Ladislau Szasz of the Institute of Geology and Geophysics,
Bucaresti [Bucharest], who has contributed much to thepaleontology of the Cretaceous Mollusca and biostratigraphy.

Observation.- The holotype (JG. H2901) and paratypes(JG. H2794, JG. H2798 and JG. H2903) are closed valves,
but the valves are somewhat displaced along the commissure plane. These specimens are internal moulds for themost part but the prismatic and nacreous shell layers are
partially preserved. The shell is slightly higher than longwith l/h=0.92 on average, gently and uniformly inflated
along the growth axis. The umbo is small, terminal andslightly projected over the hinge line. The anterodorsal
part is narrow and steep or nearly perpendicular to thecommissure plane, anterior part moderately slopes andgradually flattens out to the posterior part, which passes
into the wing-like area without any sharp boundary. The
growth axis is nearly straight. The anterodorsal margin isnearly straight, anterior and ventral margins form a semicircular outline, passing gradually to the broadly arcuate
posterior margin, which forms an obtuse angle with thehinge line. The hinge line is slightly longer than half ofthe shell length on average. The hinge structure is invis-

h

b

b

Figure 4. Basic linear measurements and angles. h: shell height, I: shell length, b: shell breadth, H :maximum linea~ dimension from umbo to ventral extremity, L: maximum linear dimension perpendicular to H,
GA: growth axIS, s: length of hinge line, a: anterior hinge angle, 'Y: posterior hinge angle, 0: obliqUity, angle
between hinge line and H.

990.

Inoceramus from Coniacian of Hokkaido

Figure 5. Inoceramus (Platyceramus) szaszi Noda and Uchida sp. nov. All figures natural size. 1a- d. JG.
H2898, paratype, from loc. Ik2709. 2a- c. JG. H2794, paratype, same locality.

147

Masayuki Noda and Shigehiro Uchida

148

ible.
The ornamentation of the shell consists of major andminor concentric sculptures in combination, which are
weak and obscure near the umbo. The concentric undulations are low, round-topped and disposed at irregularintervals; the minor rings develop in umbonal region andalso superimposed on the undulations. Fine lirae are
discernible near the umbo of the specimens JG. H2903
and 3099a.
Biometry.- The basic linear measurements and angles
are shown in Figure 4. The measurements of selectedcharacters and their statistics are shown in Tables 1 andTable 1.

2, respectively. As shown in Table 2, Pearson's coefficients of variation are, in general, small for all characters
examined.
The individual relative growth of shell length (I) vs. shellheight (h) and shell breadth (b) vs. shell height (h) of thetwo well-preserved specimens are demonstrated in Figure
6. The reduced major axes of b vs. h show isometry inthe two specimens, whereas those of I vs. h show negative allometry.
The ontogenetic changes of I/h, b/h and obliquity (0)are shown in Figures 7 A, Band C, respectively.' As isclear from Figure 7A, I/h decreases gradually with growth

Measurements of Inoceramus (Platyceramus) szaszi sp. nov. from Hokkaido. Linear dimensions in mm.

specimen

valve

h

I

b

H

L

L
R

66.0
62.2

61.3
57.4

17.4
14.9

74.5
68.7

62.0
59.8

-

JG. H2794

101°

32.0

101'

JG. H2898

L
R

87.8
95.2

82.0
89.6

20.6
22.0

92.8
100.8

83.0
87.0

39.1
42.6

99°
98°

JG. H2901

L
R

104.4
91.5

92.0
84.2

22.0
21.4

112.1
102.1

97.9
89.3

42.1

98°
96°

JG. H2903

L

64.8

60.6

15.0

71.8

61.5

33.2

99°

JG. H2909

L

51.8

47.0

12.1

53.6

47.0

23.8

103°

valve

y

0

I/h

l/hH~6omm

b/h

L/H

s/I

61'
64°

0.93
0.92

0.98
0.98

0.26
0.24

0.83
0.87

0.56

specimensaJG. H2794

L
R-

JG. H2898

L
R

121'
121'

66°
65°

0.93
0.94

0.93
0.97

0.23
0.23

0.89
0.86

0.48
0.48

JG. H2901

L
R

128°
131'

65°
63°

0.88
0.92

0.87
0.94

0.21
0.23

0.87
0.87

0.50

JG. H2903

L

131°

64°

0.94

0.96

0.23

0.86

0.55

JG. H2909

L

132°

64°

0.91

-

0.23

0.88

0.51

l/hH~6omm : ratio of I:-

h at the growth stage of 60 mm in H.

Table 2.

L: left valve, R: right valve.

Biometric characters of Inoceramus (Platyceramus) szaszi sp. nov. from

Hokkaido.

N

m

s

v

a

y

0

1/h

1/hH~6omm

b/h

L/H

s/I

8
99.4
2.20
2.21

6
129.3
2.25
1.71

8
64.8
1.28
1.98

8
0.921
0.0196
1.99

7
0.947
0.0390
4.21

8
0.233
0.0139
5.97

8
0.866
0.0177
2.04

6
0.513
0.0344
6.71

N: sample size, m: mean value, s: standard deviation, v: Pearson's coefficient ofvariation

-

-

990.

Inoceramus from Coniacian of Hokkaido

I.b

149

I/h

90
80

A:

70

/

1=1.201ho.939
r=0.999660
50

1=1.221 ho. 938

B:40

JG.H2794L

A

1.10

JG.H2898L

I. 05

1.00

r=0.9994

JG.H2901R"~:~-~~"
'"

0.95

30

....&

JG.H2903L'"",:,;:~,,,,;;::; :c:~>;;::-_c::::::_ c._

c. cc

0.90
0.85

20
10

20

304050

60

70

80

90100

Hmm

60

70

80

90

100

Hmm

100

Hmm

b/h
10

"

9
8

,,"

7 ""

B

o 35

,,"

o 30

6

b= 0.245ho. 995

5

/

4

/

/

/'

"

/.

/.

"

""

"

0.25
0.20

0.965

B

/ "
2

r= 0.9977
b=0.272h

""

3

A

""

r =0.9908

A..------. JG.H2898l

B0-----0

10

20

30

40

50

c

JG.H2901R
70.0-_----0..---__

0- ___ __~-----o--1 ~~~~--------r---~--~--~~~~~--6 7 8 9 102030
40 50 60 70 8090
h

65

Figure 6. Diagram showing the individual relative
growth (I vs. hand b vs. h) for selected specimens of I. (PI.)
szaszi Noda and Uchida sp. nov.

60

up to H =50 mm in each individual, whereas the b/h andobliquity (0') are nearly constant throughout growth asshown in Figures 7B and C.
The profiles of the two specimens in three directions
are illustrated in Figure 8.
Remarks.- The specimens examined are well preserved
without secondary deformation, but the valves are somewhat displaced along the commissure plane. The prismatic and nacreous layers are preserved and the surface
ornamentation is precisely observed in JG. H2794, 2903
and 3099a. JG. H2901 and 2909 have only the inner
layer and JG. H2898 is an internal mould with partiallypreserved inner shell layer. Several small pits are scattered on the surface of the mould. These are probably
the marks of hemispherical pearls produced to coverareas of shell killed by boring barnacles (Seilacher, 1969).
Such small pits are commonly observed on the internalmoulds of certain inoceramid shells.
Comparison and discussion.-It is noticed that the
sample from loc. Ik2709 is clearly discriminated mor----0------0- __.... 0.- _ _ --.., _...

-:-!:'- - -~- - - -n.-.- _ .....6... - .....

....... - -

55

10

20

30

40

50

60

70

80

90

Figure 7. Diagram showing the ontogenetic change of
selected characters of I. (PI.) szaszi Noda and Uchida sp.
nov. A: ratio I/h, B: ratio b/h, C: obliquity.

phologically from other samples by means of t-tests, otherbiometric analyses and precise observation. The specimens from loc. Ik2709 have a considerably inflated umbonal region, as shown in Figure 8, in comparison withthose of I. (PI.) mantelli (see Noda and Toshimitsu, 1990, p.
502, fig. 11), and show a comparatively steep posterodorsal flank. As is clear from Table 3, the results of ttests indicate that the mean values of b/h are alsosignificantly different. The ontogenetic change of I/hand obliquity (0') is clearly different between the present
species and I. (PI.) mantelli. Namely, I/h of the present
species decreases gradually up to a growth stage 50 mm
in H and then becomes about 0.95 on average, whereasthat of I (PI.) mantelli decreases continuously to the full-Masayuki Noda and Shigehiro Uchida

150

RV

LV

c

A

B

c
Figure 8. Profiles of two selected specimens of I. (PI.) szaszi Noda and Uchida sp. nov. in three directions.
A: vertical section along the growth axis, B: transverse section at the highest point of shell convexity,
perpendicular to the growth axis, C: transverse section at the broadest part perpendicular to H.

grown stage. The shell obliquity is about 65° in thepresent species, whereas that of I. (PI.) mantelli gradually
increases with growth (Noda and Toshimitsu, 1990, p. 500,
fig.10C). The individual relative growth of I vs. hand b
vs. h are shown in Table 4 and Figure 6; the specimensshow negative allometry in I vs. h and isometry in b vs. h,whereas the specimens of I. (PI.) mantelli show negative
allometry in both characters. From the above comparison the present specimens can be morphologically discriminated from the specimens of I. (PI.) mantelli.
I. (PI.) troegeri Noda, 1992 from the lower part to lower
portion of the middle part of the Coniacian of Hokkaido
shows a large extent of variation. The specimens JG.
H3010 and 3011b resemble the holotype of the present
species in equivalveness, gently inflated shell and weakornamentation. However, JG. H3010 and 3011b are elongated along the growth axis (L/H=0.76-0.79), and have alarger posterior hinge angle, ranging from 135° to 143° andsmaller obliquity (0=59°-61°) if compared with any speci-

men of the present species (compare Noda, 1992, table 1
and p. 1320, 1321 with Table 1 of this paper). Moreover,as shown in Table 3, the result of t-tests indicates thatsignificant differences exist in the characters of a, y, 0,
I/h and L/H. This fact suggests that the sample from loc.
Ik2709 is morphologically different from the sample of I.
(PI.) troegeri at the population level. As to the
ontogenetic change of selected characters, the specimens of I. (PI.) troegeri show nearly constant values of I/hand obliquity, ranging from 0.89-0.95 and 56° -60°, respectively, and b/h decreases gradually with growth, whereas
in those of this species I/h decreases gradually up to 50
mm in H and then becomes constant, ranging between
0.90 and 0.94, and b/h and obliquity are also nearly
constant, ranging between 0.23-0.28 and 61"-70°, respectively. Furthermore, with respect to individual relative
growth of the holotype and another well-preserved specimen of I. (PI.) troegeri, the relation between I and h isisometric, and the relation between band h is negatively

990.

Inoceramus from Coniacian of Hokkaido

151

Table 3. F-test and Student's t-test for selected characters of Inoceramus (Platyceramus)
troegefi Noda, I. (PI.) szaszi sp. nov. and I. (PI.) mantelli de Mercey.

As
F valuesignificancet valuesignificance
B

N
m

s
F valuesignificancet valueSignificance

I/h
25
0.888
0.05692.1289

L/H
25
0.782
0.02862.6109b/h(18)(0.225)(0.0193)1.9302

s/I
21
0.490
0.02561.8057

25
93.2
4.95
5.0625

y
24
140.1
3.66
2.6460

0

0

0

0

0

0

4.925

6.857

5.854

2.610

1.052

7.794

1.801

8
99.4
2.20
18.4900

6
129.3
2.25
17.3056

8
64.8
1.28
8.2208(7)(0.947)(0.0390)4.529380.233
0.01396.670580.866
0.017716.4552

6
0.513
0.0344
3.6477

2.930

2.453

7.429

0.150

2.597

1.139

0.023

a

N
m

•
•

•
•

•

•
•

0
25
60.3
2.04
2.5400

•

•

•
•

•

0

•

•
•

•
•

0

0

0
0

(16)
(14)
(14)
(14)
27
24
24
105.2
124.1
(57.2)(0.951)(0.205)(0.843)0.511
C(3.67)(0.0830)(0.0359)(0.0718)
s
9.46
9.36
0.0657
A: I. (PI.) troegeri, B: I. (PI.) szaszi, C: I. (PI.) mantelli. The values in parentheses show at thegrowth stage of 60 mm in H. The t-values underlined were calculated by Welch's method. . :significant, 0: not significant, at the level of 5%.
Nm

Table 4.

Comparison of individual relative growth of I. (PI.) troegeri, I. (PI.) szaszi and I. (PI.) mantelli.

specimen

al.h

(3l.h

fl.h

evaluation

ab.h

flo.h

fb.h

0.896 0.403 0.9978
0.773 0.523 0.9985

evaluationA

JG. H3011bR
JG. H3023L

1.001 0.921
0.990 0.921

0.99970.9999isometry
isometrynegative allometry
negative allometryB

JG. H2898L
JG. H2901R

0.939 1.201
0.938 1.221

0.99960.9994

negative allometry
negative allometry

0.995 0.245
0.965 0.272

0.99770.9908isometry
isometryC

JG. H2917R
JG. H2923R

0.768 1.950
0.896 1.260

0.99280.9978

negative allometry
negative allometry

0.837 0.330
0.840 0.420

0.99270.9988

negative allometry
negative allometry

A: I. (PI.) troegeri, B: I. (PI.) szaszi, C: I. (PI.) mantelli. al.h: growth index of I vs. h, (3l.h: Y interceptof I vs. h, fl. h : correlation coefficient of I vs. h, ab.h: growth index of b vs. h, flo.h: Y intercept of b vs.
h, fb.h: correlation coefficient of b vs. h.

allometric, whereas in the present specimens I vs. h isnegatively allometric and b vs. h is isometric (see Table 4).
I. (PI.) cOllignoni Sornay (1964, p. 169, pI. 1, figs. 1-3) fromthe Coniacian of the Tsiribihina Basin of Madagascar
resembles the present species in the gently and uniformly
inflated shell, moderately sloping posterodorsal area andweak major ornament. The former, however, is clearly
different from the latter in its short and concave anterodorsal margin, large anterior hinge angle (a =ca 130°) andnearly elliptical outline. The variation of I. (PI.) collignoni
is not clear, being represented by a single specimen.
A specimen of I. (PI.) mantelli subrhenanus Seitz, 1962
from the Lower or Middle Coniacian of the Brezoi Basin,
Romania, figured by Szasz (1974, pI. 14), closely resembles
the specimens from lac. Ik2709 in general outline, shellconvexity and surface ornamentation, but that specimen
has a slightly concave anterodorsal margin. Its anterior
hinge angle is about 95° in the immature stage and 110° in
the adult, and its concentric ribs and rings are narrowly
bent at the ventral part, although the variation of thissubspecies is unknown, being here a single specimen.
His specimen resembles also the specimen JG. H3022(Noda, 1992, p.1316, figure 3, holotype), JG. H3010 and
3011b of I. (PI.) troegeri. Sornay (1986, in a letter to
Matsumoto) pointed out that it is doubtful whether Szasz's
specimen is referable to I. (PI.) mantelli subrhenanus.
To sum up, the present species represented by asample from loc. Ik2709 is new, because it is identicalwith neither I. (PI.) troegeri nor any other previously named
species of Inoceramus (Platyceramus).

Masayuki Noda and Shigehiro Uchida152

A specimen of I. (PI.) n. sp. 2 described by Lopez (1990,
p. 293, pI. 13, fig. 3) from the Lower Santonian of the NordCastella platform, Spain, closely resembles the present
species in its general outline of the umbonal region, shellconvexity and weak surface ornamentation. But it is toohigh in stratigraphic occurrence to be assigned to thepresent species.
Occurrence.-For the location of Ik2709, see Figure 1.
Topographic map, Ikushunbetsu Quad. 1 : 25,000. Long.
141"51'22"E, Lat. 43"17'50"N. A cliff of the forestry road
along the Ponbetsu-gono-sawa. Among the assemblage of species (see p. 41, 43) from there I. (I.) uwajimensis occurs abundantly in the Lower to Middle Coniacian of
the Japanese scale (see Matsumoto 1984, table 1), and I.
(Cr.) mihoensis and I. (Co.) kawashitai are common in theUpper Coniacian. Hence, the stratigraphic position of thetype material is ascribed to the upper part of the Middle
Coniacian.
Loc. Ik1623. Topographic map, Ashibetsuko Quad. 1 :25,000. Long. 142"04'22"E, Lat. 43"15'53"N. A float
from upper reaches of a branch of the Kumaoi-zawa.
Discussion of phylogeny

Inoceramus (Platyceramus) szaszi sp. nov. from theupper Middle Coniacian is presumably a descendant of I.
(PI.) troegeri from the Lower to lower Middle Coniacian,because the specimens JG. H3010 and JG. H3011b of I.
(PI.) troegeri seem to foretell the specific characters of I.
(PI.) szaszi. Nevertheless, the specific distinction is clear
as mentioned in the foregoing pages. This suggests asisterhood relationship between I. (PI.) szaszi and I. (PI.)
mantel/i, both of which were derived from a common
ancestor, Le., I. (PI.) troegeri. Various species of I.
(Platyceramus) from the Santonian and Campanian may bedirectly or indirectly descended from I. (PI.) mantelli (Noda,
1983; Noda and Toshimitsu, 1990; Noda, 1992), whereas
no presumable descendant of I. (PI.) szaszi has hitherto
been found from a higher horizon. Hence, I. (PI.) szaszi
may be an offshoot from the root of I. (Platyceramus).
Conclusions

Based on a sample from the upper Middle Coniacian of
the Ikushunbetsu area I. (PI.) szaszi sp. nov. is proposed.
It resembles I. (PI.) troegeri and I. (PI.) mantelli. As far as
the sample is concerned, the extent of variation is small inevery character and is discriminated morphologically fromother allied species by means of statistical analyses andprecise observation.
I. (PI.) szaszi is regarded as a descendant of I. (PI.)
troegeri but is probably an offshoot from the main stock ofInoceramus (Platyceramus).

with instructive suggestions. We wish to thank the late
Dr. Jacques Sornay of France for his valuable comments
and helpful suggestion on I. (PI.) mantelli through Matsumoto. We are much indebted to Mr. Takemi Takahashi of Mikasa for his help in our field work. Our thanks
are extended to Mr. Kikuo Muramoto of Mikasa Museum,and the authorities of Iwamizawa Forestry Office for giving
facilities for the field work.
References cited

Heinz, R., 1932: Aus der neue Systematik der Inoceramen. Mitteilungen aus dem MineralogischGeologischen Staatsinstitut in Hamburg, vol. 13, p.126.
Lopez, G., 1990: Inoceramidos (Bivalvia) del Cretacico
Superior de la Cuenca Navarro-Cantabra y de la plata
forma Nord-Castellana. Paleontolog i a y
Bioestratigrafia. Ph. D. Thesis of the University ofAutonoma Barcelona, p.1-515, pis. 1-17.
Matsumoto, T., 1984: The so-called Turonian-Coniacianboundary in Japan. Bulletin of the Geological Society of Denmark, vol. 33, p.171-181.
Matsumoto, T. and Noda, M., 1985: A note on an inoceramid species (Bivalvia) from the Lower Coniacian(Cretaceous) of Hokkaido. Transactions and Proceedings of the Palaeontological Society of Japan,
New Series, no. 140, p.263-273, pis. 41-44.

Matsumoto, T., Okada, H., Hirano, H. and Tanabe, K.,
1978: Mid Cretaceous biostratigraphic succession in
Hokkaido. Annales du Museum D'Histoire Naturellede Nice, vol. 4 (for 1976), p. XXXIII-1-XXXIII-6; XXXIII14-XXXIII-18, 9 figs.
Noda, M., 1983: Notes on the so-called Inoceramus
japonicus (Bivalvia) from the Upper Cretaceous ofJapan. Transactions and Proceedings of the
Palaeontological Society of Japan, New Series, no.
132, p. 191-216, pis. 41-46.
Noda, M., 1986: A new speCies of Inoceramus (Cordiceramus) (Bivalvia) from the Coniacian (Cretaceous) of
Hokkaido. Transactions and Proceedings of the
Palaeontological SOCiety of Japan, New Series, no.
142, p. 354-365, pis. 69-73.
Noda, M., 1992: Inoceramus (Platyceramus) troegeri sp.
nov. (Bivalvia) from the Coniacian (Cretaceous) of
Hokkaido. Transactions and Proceedings of the
Palaeontological Society of Japan, New Series, no.
168, p. 1311-1328, 10 figs.
Noda, M. and Toshimitsu, S., 1990: Notes on a
Crataceous Bivalvia Inoceramus (Platyceramus)
mantelli de Mercey from Japan. Transactions andProceedings of the Palaeontological SOCiety of Japan,
New Series, no. 158, p. 485-521,16 figs.
Seilacher, A., 1969: Paleoecology of boring barnacles.
American Zoologist, vol. 9, p.705-719.
Seitz, 0., 1961: Die Inoceramen des Santon von

Nordwestdeutschland. Teil. 1 (Die UntergattungenAcknowledgments

We express our sincere thanks to Professor Emeritus
Tatsuro Matsumoto of Kyushu University for his kind help
in the field work and also critical reading of the first draft

Platyceramus, Cladoceramus und Cordiceramus).
Beihefte zum Geologischen Jahrbuch, vol. 46, p.1-

186, pis. 1-15.
Sornay, J., 1964: Sur quelques nouvelles especes
d'inocerames du Senonien de Madagascar. Annales

990.

Inoceramus from Coniacian of Hokkaido

de Paleontologie. vol. 50. p.167-179. pis. 19-21.
Szasz. L.. 1976: Biostratigrafia :;;i Paleontologia
Cretacicului Superior din Basinul Brezoi (Carpatii

153

Meridionali). D~ri de seam~ ale ~edintelor, Institutul
de Giologie ~i geofizic~, vol. 62. no. 4. p. 189-220. pis.
1-21.

Ashibetsuko %5JUml. Fukagochi ~ViJ~. Ikushunbetsu (= Ikushmbets. Ikushumbetsu) ~~5JU. Iwamizawa :Ei~YR. Jonan :lJi!Gi'W. Kumaoi-zawa R~~YR. Mikasa =.~. Ochanomizu :101i\;O)7.K. Oita -:k.ft. Ponbetsu (=Pombets. Pombetsu) ~5JU. Ponbetsu-gono-sawa~
5JUliO)YR. Takino-sawa \'itO)YR. Takiyoshi-zawa \'ita-YR. Yezo C~

154.::h* -r(7)~~~<7)J1:> I? * Lo

B*ii1:.~~fdj: 1995 if:~~~~nW~if:~.~,~~.M.fB*ii1:.~~~

Transactions and Proceedings of the
Palaeontological Society of JapanJ ~i;ffF C 1*jt~~.lb* c ~* c ~·~te L, 6 ~ 23 B f;:;l1i@t'~m EI ~M~~L"1miJ>nt.:W.A~L"IT~f;:~A~~~..lEiJ'~~~~ 1'5- • *2 _:~~~~k.lb~,a*2if:U~~bkDW.a~~;u~M.~a~~$~~.W~~.lb~~*Lko~~.M.~i;ffFc1*jt~~~~~.~~~_~~~~

EB fj:, gHr~.M.i;iJ~ii1:.~~ C I,~? ;f4~~pg~~OO:~~~Lk~~~~<, .~~~~m.~.c~?J?~~~~-9-~~,~, .i;iJ~*~~·, ~jj..~:W:F~jj..~1vlJi;~f;:i;

ffF~~ <+ f;:~2tt L ~ ~ ; ~~I,~,~,,IjlU~~~fj:,* t.: B*fH;:~~.1SE:P~~~f;::.t3I,~~ ~ §nk"f.\WIsJ] f;:j;: ft ~ C I,~?~~~~~m.~;~~~*Lko~f;:i;ffFf;:-:JI,~~fj:, ~a~af;:.\WIsJ]8"J~i;ffF~:Ol¥~ ~pt.:t!.< ~iJ~, :&~~* LI,~cP?::' c~, ii1:.~~cl,~? ;f4~~pg:&:~ ~ < -$~, LiJ> ~ OO~~.c L ~..b ~ b LI,~~~i;ffF c I,~? ~*1J~~0J.J;~f'rl,~ * L t.:o ~ ~*B*,
1993 if: 11 ~ 30 B ~m.lb-l;7] D * ~'f;: 251tj:~J;tJ.J;iJ~~ D *Lt.:o ::.n;~J;tJ.J;~$iJ>;, M.~a~iJ~$,[.'f;:~D~lJ.. ~ fj I,~, :& ~ 8"J f;: fj: Wf. M.i; fNipponitesJ lilU Jm
Quarterly Journal of Palaeontology~, 7/"f:-t-1 r
Nipponites ~~ L ;-:d.:tJ '7-f-!f-1 /~~*S;~OO~!t&c L ~~fU~ ~_~ 1994 if: 6 ~~~*~·~W.a~~~;EL, 1995 if:~~~~~~~1'5-T~H~~j&Jlt!rf;:.?t? ~:.t3 D* lJ.:~~.? -1r )v~:Ol¥~a~~a(7 )v 7 7 -"Z 'J rlilf{,~.

-1~ C*

ii&ffFlBfi)
Fax No,:k):~..lE~, **1C~1~ (7t.:r**1C~~tJ)/h~n* Lt.:o03-3815-9490:m (~t :k):011-746-0394~1tE~rr;, ~#ii$!J[mfJT$~-7 C*~t:k):-lj- / ::tlif1\~, tiH~$!J[

022-217-6634/J\rl ~1:. (i; :k) :7t.:r**1C, ii1:.~-~
iii? Or.!fi'fJ Oj~ :k):052-789-3033
075-753-4189

ii1flt.~:jj;j1~D~ (;f4M):

ii:jj~

03-3364-7104~A~~:Ol¥f;:~t.:?~fj:,

1, ~< ~:W:F~7t!I!J~1~~~
2, :k~~; Uf;:M~~M1*~~~.lb~~, 3, r.t1,~j:iH~iJ> ;if:~~ ~:Ol¥ ~~~, 4. jj..OO~M±~~l~ Lt':A~~,~.lb~, 5.~~EI~~M~~~~~~~~~LkA~~.lb~,c ~? t.:,~~:Ol¥. L ~~~d~~a ~~;EL * Lt.:o~~~ 51t- )v~:1f~ ~ ~(7) § 8{] t .::h*-r(7)5%tlJo

1997if:4~iJ>;Wf?-1 r)v~~~.~~fU~~::' c ~Moc::.~~, if:~~~~~n-:JM.~a~~;u~w.a

j=JjH;:, *if: 12 ~ fj: C:.lb * ~ f;:, Wf? -1r )vi; ~~;E L, ~~~.* t.:~a~Fa~~·Wf.M.i; fNipponitesJ fj:~jj..~:W:F~

n~~;E~ ~ 7"0 -t ~ f;:-:JI,~~*~1'F~L~*f;:~$~ ~jj..~1Vf~~f;:~m~ n~l,~fiiJ> DiJ>~~2~~*1J~f;:iiilJ..

::. Co *t.:~~f;:-:JI,~~~~~f-!f-1 /~~~.~~*S;f;:~ ~ 7" 0 -t ~ (~1* 8"J f;: fj: ~ ~ a iJ> ; ~ ::J / -"Z f;: ~ ~ ciJ>, :W:F~~ j"-!f-1 / Im f;: 1'F~ ~11X~~ ~ c iJ> f;: -:J P~)
f;:-:JI,~~ ~JJ.j{*~:Ol¥~, ~~*f;:~$~~::' Co:P}:Ol¥~-"Z ~ ~~ ~ c ~ ? FQ~~iJ~#~ L, _m~m.~ iJ>;,~a~~~~~~~?~~~.~ff?::,cc~D*Lko• •MIT~*~;~a~~~=~-~V?-~~1'5-~~~n*LkJ?~, ~~~.~*6*~w.a~*~.~~~.~.~V3~.~"f*#~~~~n*Lko~~*B*, ~.ffl~f;: ~ ~2~n ~ ~ D * L,f.: J ? f;: 1995~:.t3, i;ffF~;E~~k?~~~*1J~~, ii1:.~~c~?;f4~~pg:&:~~<-$~,
i;ffF~~~::. c~~~o

LiJ>~OO~.c L~..h~bLI,>*k~~f;:-:JI,~~fj:E:P,ljlUjtffl~:Ol¥

if:4~-%fj:v:t*~.i;· f-!f-1 /~~*f;:Wf1*jt~OO~~!t&.~~ C.1Sd;~ I,~fj: 21S~tJ '7-,IjlU D ~fBrm~$TWf~

c L ~ te!t&~ ~ iJ~, ? -1 r)v f;: -:J I,~ ~ fj:, ~.lb ~ ~;E-=f~~ ~:Ol¥ ~ ~ _f;: ~ D * L t.:o 1995 if: 4 ~ -%fj:Wf1*jt~OO~~.\WIsJ]8"J~f-!f-1/~~~::'cc~~o!t&cL~&~W.~:.t3-=f~~~*~nkc:.t3D~~o~,~.a~fj:Wf~~.? -1r )V~~;Ef;:M~ 61,~? ~ I,~~

m~w~~~~W.a~~~B(6 ~ 24 B), ~a~~:f.f::.n*~~H.~.~c, *~a~~~.~~-"Z~ft_~pg:&: (Wf? -1r )vi;~~JE c ~ ~~JE7"o -t ~ f;: -:J I,~_~~~o~;:P}te~L.W~~~~~*$~~, ~DA~~JJ.j{*~:Ol¥~~::' C,~.~Jl![~ 6::' c f;:l,~t.: L * Lt.:o ~a~m~fj:~.a~$~ ~ ~;E7"0 -t ~ ~JJ.j{*~~.lb 6)*t.:~~~tJ'7-f-!f-1 /f;:-:JI,>

iJ> ;~*iJ~1~i; Lt.:~a* (/J\rl~1:.iJ~1~i; ~ nk) c ~f;: -:J 1,> ~iIi~~1TI,~,~.~m.f;:-:JI,~~~Lfil,~* Lko ::.n*~f;:, ?-1 ra~$~;UT~~~n~~~:Ol¥.L, 5i;~~A~~a~~;E~~k?~~~*8"J~:Ol¥~1J~, ~n~n~~a~155t? :m::iF l, L I. ) 1.:: t! ~ * l, t.::0

~ ffii 0) q:r iJ> t? Ii Wcst3t 0) :11

frif~-I;J] ~ : 1995 if: 8 fj 30 B

~N~O):m:*~m~~~hL~~*~o~~ ~ffiiO)W.
~t?0)~:m:*0)~~1.::~~~~~~:11~~0).~~h~
1T~ L I.) < 75El"~ 0~~(7)~."(7)t3H~'0 ~®.::Jt3t0):11 ~ IH;: 1m l, L Ii,~ ffii~ffii ~;:~j]i¥J~~~~~;t L I.) t.:: t! < O)iJ~,l, <,a ~:m ***~t?li0~~~/'(~l"~.Q t,lGI,J.,)*~iJ~, ~@)~3$*l"0)~OOO)~~0)1m~l"~~~0~0)~~t~*~~o l,~l"B*il~~~~~~ • *c~: Transactions and Proceedings of the Palaeontological Society of Japan v;: ;:+:m:*0)~~ t.::~~, ~~O):1'o ~ A t*5*~;:":H)L li~~ l, LJ.,)~ ~o)l"~ffiiO)W.~;: litt~i* <~~~ L J.,)1.::t! < t t~~;: ;:+3i:m~~JjjJ.,)J.,)t.:: l,~:11 ~ Iv~~Ltl, LPtd! < Ll"o)~~* L+~;:~)~O)11f**¥~~~E;t l,*~oB*il~~~~t~~~~~G<~~l,1.::,~~O)M~*l"~~ffii~t?~:m:*O)~~1.::~~li:11 ~ Iv~~~ffii~l"~~~~o)Xj~ t ~-ttLJ.,)t.::~,~~*~O)~ ~ffiiO)W.~~~j]i¥J~~~O)~:m:*~.

~~3t~ ~;:~]!! l"~* J: ?
~~ Jjj p $ l, ~ vi

*

0

~0

B*~~~~,

B*A!fJ[~~,

B*~~~

B*JA~~~liJ~H;:~

5'!-OOAO) co-editor, associate editor ~~ jill;t, OO~~3t{G ~ Ii iJ> ~ L J.,).Q
h t? O)~~O)®.::Jt3t:11 ~ lvli~)~o) t ~ ~ l"~
0

;:

0

~~3t0)~~: il~~~ t I.) ? f4~0) iAJ~ ~ J: < E;t,l,iJ> ~ OO~~3t t l, L.b ~ b l, J.,)®.::Jto)~~o~{'.t7t: T 464-01~il§nIJTfilZ/l'~1HJ

B *~~~~
B *~~~~B *A!fJ[~~
B *JA~~~~ il §!*~J'lI!.~$:t~f:jt~£f4~<l&~Zoological Science
Journal of Plant Research
Anthoropological Science
The Japanese Journal of Genetics(®.::Jt3t:11 ~ lv~~~ffii~)IN"~~ (®.::)t3t:11 ~ lv~~~ffii~~ffii*)* l"j)~0);: to~l"~;:h* ~0

r{GEJ 58-15-l"~fflt?-ttl,t.::J:?~;:,~)~0)J:?~ r§~~~~~irJ :±f!go)Y/~~7J,.·~VIlfW'i'~~iJ~1Tb

1Il!\~li~flL+~O)L" ~ffiiO)W.O) ;:+~1JD~~jilll, * ~ 0

B~: 10fj 7 B (±) q:1W10~~q:i&5~~~: !f-fI1HE*~OO~~~ji~#i**~c~;:J\-lv (!f-fiSEEl*~lffi!f-fiSEEl:f f /)\A~tr~lW,

a* ~ !£R:W~!f-fiSEEl!£R* t.::Ii *lffi**!f-fiS EEl!£R, JRrmEElf.!fr~!£RiJ>t?~)'\A~~~ *~o )T-?: r§~tAra~0)~~-21 i!t*cO)§~~f4~O)iiif~t<l&WO)~:m-J~

1!f: il~~~~iJ>t?:iffi**~flm:),

m, ~~1l5~jjIij~ffiio)l;];iJ>, Brm1iJ(~ (~~~:lI*), $~ fttX (**~flm:), *~*~ (*w*r¥- (~~OO:lI*) 0)1J!ZiJ~75E~hLJ.,)*~o

~~"I
~

[g~~

(1995-1996)

513~

E~

OO~(~$)

110_~~'J\~W-.[g~~~;ffiff1¥-&;83$J't:lfZlI!f~(~~~)

~~

M;ff

~~~~~

J\~

Bt!

*~~~fiR.~~.m~,~~~~.~~R,~$~W$~~.M~~~~VR.~~~iJ' ~ ~~.iJ)~L ~n LV) *~ :EJ!1±~.~~~ ~j:Tg6~Jm I) --C'~0-1 /' F;?, s/7EnB~A~t±~~!Jf.-:V:AtE!~~1W!jo/]tt(7 -1 ,/.::c::t JI~).:::.#EnBOO~~A~t±~

1995 if: 6 ~ 27 B

Ep

,\jlU

1995 if: 6 ~ 30 B

9B

1T

fi ~

B

:$:

0031-0204

B *~1:~~~~15 . *[.$

2,500 F9

~

~

~

~

~

'1' 113 J!OiOlllXg 1R*~j6 5 -16 - 9
B*~~$~~~?'-F*3

millS

Rm 178 %

1W

!jo/]
tt
EnBi:7mtOO~~A~t±

7'. -1 t-' :::I /' -lj- Iv 7' /' 1-

~

E

~

~ ~ 11 1'1'I"$:v: E! ~ ~ 1W !jo/] tt

ISSN

0

i\i~~

~

i\i~~$jj!;

fP AilU~*

03-5814-5801~·:pdf.ITOO!m{§ )ft'1'9841Jl1il'm:;s1*IZ1\TO)§51BJ8-45
m~tl:lIi&EP,\jlUf*~~t±m~$~*t± 022-288-5555 ~g 03-3455-4415

Transactions and Proceedings of the PalaeontologicalSociety of Japan
June 30, 1995

New Series No. 178
CONTENTS
TRANSACTIONS
987.

Shiro Hasegawa and Ritsuo Nomura : Redescription of Asano and Nakamura's (1937)
cassidulinid species based on their primary types .. .. .. .. . . . . . . . . . . .. . . .. . . .. .. .. .. ..

988.

Xuedong Xu and Motoyoshi Oda: Surface water changes in Ryukyu Trench slope region,

989.

Tamiko Ohana and Tatsuaki Kimura : Further observations of Cunninghamiostrobus

western margin of the North Pacific during the last 320,000 years

89.. ... .. .. ... .. ... .. . 105

yubariensis Stopes and Fujii from the Upper Yezo Group (Upper Cretaceous),
Hokkaido, Japan . . .. . .... . . . . . . . .. .. ........ ...... . ....... . . .... .. . ... . . ... . . ..... 122
990.

Masayuki Noda and Shigehiro Uchida: Inoceramus (Platyceramus) szaszi sp. nov.
(Bivalvia) from the Con iacian (Cretaceous) of Hokkaido..... . .. . ..... .... ... .. . . . . .. . 142