ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 142

Palaeontological Society of Japan
June 30, 1986

Co-Editors

Hisayoshi IGO and Takashi HAMADA

Officers for 1985-1986
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Itaru HAYAMI, Hisayoshi IGO, Junji ITOIGAWA, Tadao KAMEl, Tatsuaki KIMURA,
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The fossil on the cover is Unuma (Spinunuma) echinatus ICHIKAWA and YAO, a
Middle Jurassic multisegmented radiolaria from Unuma, Gifu Prefecture, central
Japan (photo by A. YAO, x 260).

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Trans. Proc. Palaeont. Soc. Japan, N.S., No. 142, pp. 341-353, pis. 65-68, June 30, 1986

811. GINKGO TZAGAJANICA SAMYLINA FROM THE PALAEOGENENODA GROUP, NORTHEAST JAPAN, WITH SPECIAL REFERENCETO ITS EXTERNAL MORPHOLOGY AND CUTICULAR FEATURES*
JUNJI HORIUCHI and TATSUAKI KIMURA.

Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Tokyo 184

Abstract.
Many fossil Ginkgo leaves with well-preserved cuticles were obtained from the Lower Palaeogene Noda Group distributed in the Pacific side of
Iwate Prefecture, Northeast Japan. Judging from the occurrence, external morphology and cuticular features, these fossil leaves belong to the same species andwere derived from the same population. They are referable to Ginkgo tzagajanica
originally described by Samylina from the lowermost Tertiary in the Bureja Basin.
In this paper, the detailed description of Ginkgo tzagajanica and its emended
diagnosis were given. Variation of the external and cuticular features of these leaves
were also discussed. Cuticular features of Ginkgo tzagajanica vary according to the
portions of a lamina. This fact shows that careful observation of cuticular data isrequired when dealing with Ginkgo species by their cuticles. In addition, re-evaluation of some features, said to be diagnostic of Ginkgo leaves, were made based on
our fossil and extant leaves.
Decrease in development of papillae on the subsidiary and ordinary cells, since
the early Tertiary, is recognized among the Tertiary Ginkgo species hitherto known.

land (Isle of Mull; Eocene) showed that theGerman leaves were different from Scottish onesin cuticular features. So far as we know, at leastnine species of fossil Ginkgo have been recognized since the early Tertiary by means of
cuticular analyses (Table 1).
From the Lower Palaeogene Minato Formation of the Noda Group (Sasa, 1932), over sixty
well preserved leaves and many leaf fragmentsof Ginkgo were collected and prepared for ourstudies. Cuticular features of our leaves vary
within a leaf according to its portions. Thesefeatures also vary from one leaf to another insome extent.
In the present work, variation and validity ofsome features formerly used for identifying
Ginkgo species are discussed using the fossil

Introduction
Fossil Ginkgo leaves resembling those of
the extant G. biloba in their external morphology have widely been known since the Middle
Jurassic. Some early authors regarded them tobe a single species and classified them as Ginkgo
adiantoides (Unger) Heer (e.g., Shaparenko,1935) or Ginkgoites adiantoides (Unger) Seward(Seward, 1917).
Florin (1936) who studied the leaves of"Ginkgo adiantoides" from West Germany(Frankfurt am Main; Upper Pliocene) and Scot*Received January 29, 1985; revised manuscript
received April 8, 1986; read October 3, 1981
at Hiroshima University.
341

342

Junji HORIUCHI and Tatsuaki KIMURA

Table 1.

List of Tertiary Ginkgo with described cuticles (*after Tralau, 1967).

G. biloba Linnaeus
G. adiantoides (Unger) Heer

G. occ.identalis

Samylina

G. gardneri Florin

G. orientalis Samylina

G. samylinae (Medjulianov)comb. nov.
G. spitsbergensis Manum
G. wyomingensis Manum
G. tzagajanica Samylina

Hikita, 1949 ; Pliocene, Japan
Iwao, 1978 ; Pliocene, Japan
LaMotte, 1936 ; Miocene, U.S.A.
Florin, 1936 ; Pliocene,
West Germany
Szafer, 1961 ; Miocene, Poland
Jordanov et al., 1963 ; Pliocene,
Burgaria*
Lancucka-Srodoniova, 1966 ; Miocene,
Poland*Givulescu, 1973 ; Pliocene, Romania
Samylina, 1967b ; Palaeogene, USSR
Florin, 1936 ; Eocene, Scotland
Samylina, 1967b ; Palaeogene, USSR
Medjulianov, 1969 ; Palaeogene, USSR
Polyshchnuk, 1975 ; Late EoceneEarly Miocene, USSR
Medjulianov, 1969 ; Palaeogene, USSR
Manum, 1966 ; Palaeocene, Spitsbergen
Manum, 1966 ; Palaeocene, U.S.A.
Samylina, 1967b ; Danian, USSR
Krassilov, 1976 ; Danian, USSRThis study, Lower Palaeogene, Japan

leaves from the Minato Formation and leaves ofcultivated G. biloba from six locations of fiveplaces in Japan. Brief discussion is also made on
the change in development of cuticular featuresof the genus Ginkgo and its trend since theearly Tertiary.

N
PacifiC
Ocean+

Material
Fossil Ginkgo leaves from the Minato Forma·tion were collected from three localities around
Kuji City and Noda Village, Iwate Prefecture,
Northeast Japan (Text-fig. 1). The Minato Formation is considered to range between Upper
Palaeocene and Middle Eocene according to thepalynological study by Horiuchi (MS). Materials
from the localities A and B (Text-fig. 1) are excluded from this work because of their small
number of specimens. From the locality C (Textfig. 1), the Ginkgo leaves were collected from aoL-....J2Km

Text-fig. 1. Localities (A A-C) of Ginkgo
tzagajanica Samylina in the Palaeogene Minato
Formation, Kuji-area, Iwate Prefecture.
block of 3 m x 4 m and 0.2 m in thickness in asingle bed. These leaves are considered to be
derived from a single population. The Ginkgo

811. Ginkgo tzagajanica

leaves are most predominant in this bed in association with leaves and leafy twigs of such deciduous conifers as Pseudolarix nipponica (Kimuraand Horiuchi, 1978) and Metasequoia sp., anddicotyledons.

343

Leaves of the extant Ginkgo biloba in Japan
also treated in this study were collected from
Asahikawa (Asahigawa), Hokkaido (ca. 43°50'N,
142°20'E), Kuji, Iwate Prefecture (ca. 400 10'N,
141°48'E), Tokyo (ca. 35°40'N, 138°50'E),t-----------oI00pm

Text-fig. 2. Illustrations of cuticles from a single lamina (MI0735) of Ginkgo tzagajanica Samylina.
a-b; lower cuticles of area b (Text-fig. 3) prepared from the distance of 1 mm, c; upper cuticle of areac (Text-fig. 3), d; ordinary cells of the upper cuticle, area b (Text-fig. 3).

Junji HORIUCHI and Tatsuaki KIMURA

344

Nagasaki, Nagasaki Prefecture (ca. 32°45'N,
129° 50 'E), and Ibusuki, Kagoshima Prefecture(ca. 31°10'N, 130° 40'E) to check the differences
influenced by climatic condition. In Tokyo, theextant leaves were collected from two locations
in order to ascertain the variation in leaves grownunder similar climatic condition. Their age andsex were not considered in this study.
All the specimens and slides described herein
are kept in Department of Astronomy and Earth
Sciences, Tokyo Gakugei University.
Methods
All the fossil leaves for cuticular study were
picked off from tuffaceous sandstone andtreated in Schulze's solution followed by KOH(ca. 10%), and mounted in glycerin jelly or
canada balsam. Some of them were stained withsafranin before mounting.
For the observation by scanning electron
microscope (SEM), dried cuticles were coatedwith gold by the ion sputter. The ion sputter
seems to be useful for the cuticular study because material can be coated from random directions. The coating was controlled to be about
150 A to 250 A in thickness. For SEM micrographs, HITACHI S-450 was used at 25 kv.
For the observation of resin bodies, compressed laminae were pealed off from the rocks
using acetylcellulose film or collodion, thencleared in commercial bleach.
On the nomenclature in this study
Two generic names, Ginkgo and Ginkgoites,
have often been used for fossil leaves. The fossil
leaves resembling the extant Ginkgo biloba intheir external morphology have been known
since the Middle Jurassic. We adopt Ginkgo forthese leaves following Harris and Millington(Harris et al., 1974).
Many fossil Ginkgo leaves have been describedfrom the various areas under the names ofGingko adiantoides (Unger) Heer or Ginkgoites
adiantoides (Unger) Seward. Unfortunately, no
cuticular information has been known on theoriginal specimens of Ginkgo adiantoides (Unger)
Heer. Florin (1936) considered the specimensfrom the Pliocene of Frankfurt am Main to be
identical with the original G. adiantoides (=Salisburia adiantoides) described by Unger(1845, in Florin, 1936) and he described the
cuticles of the leaves and emended the diagnosisof G. adian toides.
Samylina (1967b) suggested to put 'ex gr.' infront of the specific name for fossil Ginkgo
leaves when lacking cuticular informations.
Concerning the fossil leaves resembling those of
the extant G. biloba in their external morphol:ogy, we agree with Samylina's opinion because
it is difficult to discuss the species of Ginkgo
without their cuticular informations. She transferred Ginkgo adiantoides emended by Florin(1936) to her Ginkgo {lorinii (1967b) as nomen
novum with citation of Florin's figures. However,since there is no precise distinction between
Florin's and Unger's specimens, we prefer toretain Florin's G. adiantoides rather than totransfer it to G. {lorinii.
Medjulianov (1969) proposed a new species
under the name of Ginkgoites samylinae consisting of two varieties, G. samylinae var. samylinae and G. samylinae var. sachalinica. He included
Ginkgo orientalis Samylina, 1967b in his Ginkgoites samylinae var. samylinae as a synonym.
Ginkgoites samylinae var. samylinae should now,
in our opinion, be transferred to Ginkgo orientalis, and Ginkgoites samylinae var. sachalinica(Medjulianov, 1969, p. 147, pI. 19, figs. 4-11,
pI. 20, figs. 1-13) to Ginkgo samylinae comb.
nov. Accordingly, the diagnosis of Ginkgo
samylinae should follow that of Ginkgoites
sam.vlinae var. sachalinica (Medjulianov, 1969,
p.147).

Description of species
Order Ginkgoales
Family Ginkgoaceae
Genus Ginkgo Linnaeus
Ginkgo tzagajanica Samylina

PI. 65; PI. 66; PI. 67, Figs. 1, 3-6; Pl. 68.

811. Ginkgo tzagajanica

345

a

.
,
·
_
C

""""V

'-----'1 em,', ", " \'... -...

d,/

,,

/

.... ,\'''," ... ..
,)

J.-',,,--_ .... :

c ""
...

__ ... __ .. _...... - ... ---.........

/'

,
I

I,

,

..

,

,

'-,... ''\

----

-,

\

,,
\
\

,,
,

",'

.,
" ,,, .... -.,
"
"

,

"

I

_~If\'-'l\~h ......---.1em
1em

CJ.
I

tOo,,'" ......

,

I

\

.

,I
,

'.-'

Text-figs. 3(a-b). Division of a lamina on the basis of cuticular features. a;upper surface, b; lower surface.
Text-figs. 3(c-j):
Varied leaf outlines of Ginkgo tzagajanica Samylina from the
Palaeogene Minato Formation. c (MI0729), d (MI0733), e (MI0786), f (MI0732),g (MI0750), h (MI0736), i (MI0724), j (MI0767).

346

Junji HORIUCHI and Tatsuaki KIMURA

Text-figs. 2a-d, 3c-j.
Ginkgo tzagajanica Samylina: Samylina, 1967b,
p. 314, pi. 6, figs. 3-6 (Danian, Bureja Basin).
Ginkgoites cf. adiantoides (Unger): Oishi, 1938,
p. 105, pi. 13, figs. 1-6, text-figs. A-C (fromthe locality C of Text-fig. 1 in this paper).
Ginkgo spitsbergensis Manum: Krassilov, 1976,
p. 42, pI. 2, figs. 1-7 (Danian, Bureja Basin).

Emended diagnosis:-Leaves petiolate; cuneate
to fan shaped, basal angle 70°-330°. Incisions
shallow, one to seven in number; a median incision the deepest but never reaching halfwaydown lamina. Apical margin of lamina either
toothed or undulated. Resin bodies fusiform tooval, frequent only between veins. Veins bifurcating three to four times at all levels, persisting
to tip of marginal tooth in lamina in case of
toothed apical margin; density typically 17 per
cm at halfway-down lamina. Upper surface of
petiole longitudinally singly grooved.
Epidermis essentially hypostomatic, but withstomata on restricted portion of upper cuticle.
Upper cuticle 2 Jlm to 4 Jlm thick consisting
mainly of ordinary cells with stomatal complexes, papillae and trichomes being present in
restricted area. Ordinary cells elongated-rectangular or elongated-polygonal in shape, but
isodiametric in apical portion of lamina; anticlinal walls sinuous, amplitude typically 2 Jlm
to 3 Jlm, wave-length variable; periclinal walls
smooth. Ordinary cells of over veins moreelongated than those between veins. Stomata
restricted in distribution to basal area of lamina,
haplocheilic, dicyclic or incompletely dicyclic;
guard cell walls along aperture thickly cutinised;
aperture typically 15 Jlm long. Subsidiary cells
four to seven in number. Trichomes unicellular,

cylindrical and base peg-like.
Lower cuticle typically 2 Jlm thick consisting
mainly of stomatal complexes, four- to six-sided
polygonal cells with or without blunt papillae
and trichomes. Cells over veins more elongatedthan cells between veins; anticlinal walls ofcells between veins less marked; periclinal walls
papillate or not, each having one papilla when
papillate. Distribution of papillate ordinary cells
uneven according to portions of lamina, or
leaves; sometimes all cells being papillate, butsometimes spar sed or absent. Trichontes more
frequent on cells over veins rather than on cells
between veins. Stomata haplocheilic, usuallydicyclic, restricted in distribution to intervenal
areas. Guard cell walls along aperture thickly
cutinised; dorsal walls also showing thickenings.
Subsidiary cells mostly papillate. Aperture almost completely overarched by three to eightpapillae projecting from both lateral and polar
subsidiary cells. Trichomes unicellular, cylindrical and base peg-like. (Fructification not
known.)
Supplementary description:-As mentioned
later, cuticular features vary considerably according to portions of a lamina. They also vary fromone leaf to another. There are some cuticularfeatures varying between areas set close by. For
example, Text-figs. 2a and 2b show the illustrations of cuticles prepared from the area b (Textfig. 3b) of one lamina at distance of 1 mm. In
Text-fig. 2a, periclinal walls of ordinary cells
mostly have blunt papillae but in Text-fig. 2b,
they are only occasional. Size of ordinary cells
illustrated in Text-fig. 2a is much smaller thanthose in Text-fig. 2b. Furthermore, density ofstomata is much smaller in Text-fig. 2a than in
Text-fig. 2b. Density of stomata ranges from 66

Explanation of Plate 65
Figs. 1-10. Ginkgo tzagajanica Samylina
Figs. 1-5: Varied external morphology (all in natural size); 1 (MI0750), 2 (MI0724), 3(MI0767), 4 (MI0733), 5 (MI0732).
Fig. 6: Trichomes on the vein course (slide no. MI0741-c), x 400.
Fig. 7: A part of cleared lamina showing the distribution of resin bodies (MI0791).
Figs. 8-10: Varied developmental stages of blunt papillae (slide no. MI0741-c), x 400.

HORIUCHI and KIMURA: Ginkgo tzagajanica

Plate 65

811.

Ginkgo tZagajanica

to 106 per a square mm in cuticular preparations
observed.
In upper cuticle, size of ordinary cells overveins is typically 16 J,tm wide, and their length,
though very variable, is about 90 J,tm to 160 J,tm.
Size of cells between veins is about 18 J,tm to
25 J,tm wide and 25 J,tm to 60 J,tm long in the areab (Text-fig. 3a).
Figs. 1 and 3 of Pl. 67 show SEM micrographsof external and internal surfaces of lower cuticles, respectively. It is clear that papillae arecaused by rise of whole cuticular layer of a small
area. Oblique view of papillae from externalsurface (Pl. 68, Fig. 2) shows that papillae ofsubsidiary cells are much longer (ca. 15 J,tm) thanthose of ordinary cells (ca. 6 J,tm). Internal surfaceof guard cells is radially striated (Pl. 68, Figs. 3,4). This structure seems to be comparable withmicellae discussed by Heath (1975). Pl. 67, Fig.
5 shows the trichomes with thickened apex.
Trichomes are easily distinguishable from slender
papillae (Pl. 67, Fig. 6) by having such thickened
apex.
Discussion on the diagnostic features ofGinkgo leaves
Many features for describing Cenozoic Ginkgo
species have been discussed as diagnostic ones.
However, while studying on the Ginkgo leaves
from the Minato Formation, we have recognizedthat some of these features vary considerably as
mentioned below.
1. External morphology1-a) Size: Varied leaves are shown in Pl. 65,
Figs. 1-5 and Text-figs. 3c-j. Maximum widthand length (lamina ba!le recognized as the firstbifurcating point of veins from the petiole) of
the lamina were measured. Length ranges from
1.6 cm to 7.0 cm [mode: 4.0 cm to 5.0 cm(32%)]. Maximum width ranges from 2.3 cm to
8.1 cm [mode: 4.0 cm to 5.0 cm (33%)]. It isinteresting that the distinct relation between
these two values is recognized (Text-fig. 4). Also
plotted on the same graph is dimension of extant
and some fossil Ginkgo species. The leaf indices(ratio of length to width) are almost the same347

-G. bi/abao G.

orienralis-G. tzagajan;ctJ;:'i• G. paradlantoides
oG. digitatR

o

4

,

6

7

9

10

Width (em)Text-fig. 4. Length-width relations of laminae of selected Ginkgo species [data after
Samylina, 1967b and Medjulianov, 1969 for G.
orientalis, partly after Samylina, 1967b for G.
tzagajanica, after Samylina, 1967a for G. paradiantoides and after Harris and Millington (inHarris et ai., 1974) for G. digitata.]
value within the genus.
Sakisaka (1958) mentioned that lamina-sizeof the extant Ginkgo biloba was controlled by
the balance of water absorption and transpiration, although no detailed datum was offered.
According to him, more the water absorption
exceeds transpiration, the larger in size is thelamina. He also mentioned that lamina-size
varied within a single tree, because the amountof water supply was not unified throughout onetree.
1-b) Incision: In the extant Ginkgo biloba,
incisions are 0, 1, 3, 5 and 7 in number. Thirtynine leaves among those from the Minato Formation show well preserved lamina-margins. The
incisions scarcely reach to the halfway -downlamina. Sakisaka (1958) further mentioned thatthe number of incisions was also controlled by
the balance of water absorption and transpiration. According to him, more the water absorption exceeds transpiration, the larger is the number of incisions. From his two indications mentioned above, it can be expected that larger
leaves possess well developed incisions. Text-fig.
5 shows the relationships between number ofincision and their lamina-size in the Ginkgo

Junji HORIUCHI and Tatsuaki KIMURA

348
NumberNumberofof

Incisionsspecimens

Rangeof maximum

10

3
5

9

lamina .Iength (em)lamina width (em)11Range of maximum

2

-

3

4

5

1

7

6

.

2

-

3

4

5

6

7

8

9

20

Text-fig. 5. Distribution of lamina size in relation to their incision numbers ofGinkgo tzagajanica from the Palaeogene Minato Formation.

leaves from the Minato Formation. It is clear thatleaves with larger number of incisions (5 incisions) show wide range of lamina-size while
leaves with smaller number of incisions (only one
incision) do not attain to large size (with single
exception of 64 mm in width). Leaves with intermediate number of incisions (3 incisions) showintermediate range in lamina-size. The bias ofthis distribution within the graph may indicate
regional environmental conditions in some extent.
1-c) Vein-density: Vein-density was counted
at apex and halfway-up lamina to note whichpart shows more stability (Text-fig. 6a). As isclear from the graph, countings should be madeat halfway-up lamina. At this portion, about 35%
of leaves showed vein-density of 17 per cm, andover 65% showed 16 to 17 per cm.
Text-fig. 6b shows vein-density of the extant
species collected from four places in Japan. The
peaks show high concentration but they range
from 14 to 16 per cm without any direct relation
to known climatic conditions.
In some previous studies of fossil Ginkgo
leaves, vein-density is represented for every 5 mm

40

a

•

• half •• y.up I.mina
~m.n.

ape.

2
10

tJ. A•• hikaw.

• Tokyo .. ,o TOk,o .. 2

* lbusuki

20

10

Vein Density (per em)

Text-fig. 6. Vein-density of Ginkgo species.
a; G. tzagajanica Samylina from the Palaeogene
Minato Formation, b; G. biloba L. from Japan.

instead of 1 cm (e.g., Samylina, 1967b). It has
been examined from our observation of many
leaves that vein-density given for every 5 mmcannot be simply twiced to get the density for 1
cm. Such value usually turns out to be somewhat
larger than the actual.

Explanation of Plate 66
Figs. 1-10.
Ginkgo tzagajanica Samylina
Figs. 1-2: Stomatal complexes of the upper cuticle (slide no. MI0752b-l), x 400.
Figs. 3-4, 10: Stomatal complexes of the lower cuticle, x 400. 3 (slide no. MI0733a-b-l),
4 (slide no. MI0727-1), 10 (slide no. MI0746b-l).
Figs. 5-7: Normal cells of the upper cuticle prepared from area b. 5 (slide no. MI0733ab-l), x 100, 6 (slide no. MI0746b-l), x400, 7 (slide no. MI0772a-b-l), x 400.
Fig. 8: A cuticle prepared from area a' of the upper cuticle (Text-fig. 3a) (slide no.
MI0746a-l), x 100.
Fig. 9: A cuticle showing areas a and a' of the lower cuticle (Text-fig. 3b) (slide noMI0746a-l), x 100.

HORIUCHI and KIMURA: Ginkgo tzagajanica

Plate 66

811. Ginkgo tzagajanica

2. Cuticular features
From our observation of cuticles preparedfrom various portions of a lamina, our fossil
lamina is divided into the portions as shown in
Text-figs. 3a and 3b.
2-a) Upper cuticle: Stomatal complexes arefound only in the basal area lettered c in Textfig. 3a. Also in the same area, papillae of varied
developmental stages, blunt to slender, are found(PI. 65, Figs. 8-10, PI. 67, Fig. 6).
Ordinary cells are usually rectangular or polygonal in shape (Text-figs. 2a-c, PI. 66, Figs.
5-7), but rather short in the area c, and isodiametric in the area a (PI. 66, Fig. 8).
Medjulianov (1969) offered his data on thenumber of cell rows over veins and width of thevein-course, and indicated their systematic value.
However, in our fossil leaves studied herein, thenumber of cell rows varied mainly from 5 to 12(maximum, 17) and their width mainly from 86
J.lm to 220 J.lm (maximum, 300 J.lm). These evidences do not agree with Medjulianov's measurements. However, these two values show mutual
relations indicating stable mean value of veincourse-cell-width (Text-fig. 7).
Sinuosity -amplitude of the ordinary -cell-walls
is one of the diagnostic features commonly usedin the previous works. It is necessary to be measured on the cell walls having somewhat regularwave-length for more than two waves (irrelevant
to its actual length) to obtain the stable data.
Fossil leaves studied herein show high concentration of amplitude value (Text-fig. 8). More than
45% of the measured cell walls show amplitude
between 2 J.lm to 3 J.lm, and over 75% are placed
between 2 J.lm to 4 J.lm.
For comparison, the leaves of the extant
Ginkgo biloba from five places were examined.
All populations show highest peak at 6 J.lm (Textfig. 8). Medjulianov (1969) showed his data on
the extant species collected from Vladivostok,
USSR and Japan. Amplitude shown by him (15J.lm) was not statistically represented, thus it
could not be compared with our result.
2-b) Lower cuticle: At the basal portion of
the area c (Text-fig. 3b), cell arrangements ofover veins and intervenal areas are not well

349

350

E300

.;.

".

.. 250
~

o

U

':200

">

o

~150

~

i ,oa
o

1

2

3

"

!i

6

7

B

9

10

11

12

13

,,,

15

16

17

18

Number of cell rows

Text-fig. 7. Relationship between numberof vein course cells and width of vein courses ofGinkgo tzagajanica Samylina from the Palaeogene Minato Formation.
G. t zagajsnicB

G. biloba• A".ik ...
.lIjl• Ilk,.
~"I ... kii;llh .. ki

10Text-fig. 8. Sinuosity-amplitude of anticlinal cell walls of Ginkgo tzagajanica Samylina
from the Palaeogene Minato Formation and theextant Ginkgo biloba L. from Japan.

differentiated.
Dicyclic and incompletely dicyclic featuresof the stomatal complexes support the observation made by Kausik (1974) rather than thatby Pant and Mehra (1964).
Trichomes are frequently well developed
along vein-courses and sometimes between veins.
However, some vein-course-cells of considerable
length are provided with trichomes while someare not. Vein-course-cells prepared in extension

Junji HORIUCHI and Tatsuaki KIMURA

350

over 1 mm were selected from several portionsof laminae to count the number of veins provided with trichomes. More than 50% of theveins from the area b (Text-fig. 3b) were provided with trichomes, while only 20% of theveins from the area a were with them. In the areac, trichomes were very frequent, though as mentioned already this portion did not show clear
differences in cell arrangements. It is necessary
to be aware that in the area a, inspite of large
sized cuticles obtained, they sometimes lacktrichomes completely.
The area a, as in the upper cuticle, showed isodiametric rectangular or polygonal cells without
any stoma, and cuticle was thicker.
Comparison
Our fossil leaves are characterized by the
combination of the following three features;
1) well developed subsidiary-ceIl-papillae completely overarching the stomatal pit, 2) frequent
occurrence of ordinary-ceIl-papillae on the lower
cuticle and 3) smaller sinuosity-amplitude ofordinary-cell-walls with its mean value being
approximately 311m.
Our fossil leaves are fundamentally identicalwith Ginkgo tzagajanica originally described by
Samylina (1967b) from the Danian of the Bureja
Basin in external and cuticular features. But thedetailed observation of our fossil leaves led inevitably to give the emended diagnosis to Ginkgo
tzagajanica as mentioned previously in this paper.
The following Tertiary Ginkgo species arecomparable with G. tzagajanica: G. gardneri, G.
adiantoides, G. occidentalis and G. samylinae.
But they are distinguished from Ginkgo tzaga-

janica by the respects mentioned below.
Ginkgo gardneri from the Eocene of Isle ofMull, Scotland (Florin, 1936) has straight anticlinal cell walls, low vein-density (13 per cm),and has prominent papillae on almost all ordinary cells of the upper cuticle. Ginkgo adiantoides
from the Miocene of Silesia (Szafer, 1961) and
Pliocene of Frankfurt am Main (Florin, 1936)
has high vein-density (29 per cm according toFlorin, 1936), and its guard cells are not overarched by papillae. Ginkgo occidentalis from the
Miocene of USSR (Samylina, 1967b) has alsohigh vein-density (20 per cm), large amplitude ofcell-sinuosity (measured from the original figures
as 6 11m to 811m), and its guard cells are not overarched by papillae. Ginkgo orientalis from the
Palaeogene of USSR (Samylina, 1967b; Medjulianov, 1969) has no subsidiary-cell-papillae andshows large amplitude of cell-sinuosity (9 11m to
11 11m). Ginkgo samylinae from the Palaeogeneof USSR (Medjulianov, 1969) has very large veindensity (24 per cm), and lacks ordinary-cellpapillae of lower surface.
Ginkgo spitsbergensis from the Palaeocene ofWest Spitsbergen and G. wyomingensis from theLower Palaeocene of Wyoming, U.S.A. (both described by Manum, 1966) show close resemblance with leaves from the Minato Formation.
Taking the range of variation into consideration,
Ginkgo wyomingensis is considered to have very
close affinity with G. spitsbergensis. These two
species are also difficult to distinguish from
Ginkgo tzagajanica, but they are based on too
small number of specimens to be compared readily with G. tzagajanica. Although Krassilov(1976) considered Ginkgotzagajanica as a synonym of G. spitsbergensis, we are of the opinion

Explanation of Plate 67
Figs. 1, 3-6. SEM micrographs of Ginkgo tzagajanica Samylina (stage no. MISEM-1).
Fig. 2. A SEM micrograph of extant Ginkgo biloba L. (stage no. MISEM-2).
Figs. 1-2: External surface of the lower cuticle.
Fig. 3: Internal surface of the lower cuticle showing a vein course.
Fig. 4: Internal surface of the lower cuticle showing interveins.
Fig. 5: Trichomes with thickened apex.
Fig. 6: Slender papillae.

HORIUCHI and KIM URA: Ginkgo tzagajanica

Plate 67.' .. .'.. .
.'..
.
.•••.,.'""I.·•,r, ,...
..
r l , ,,
o

"',

"

.. ',

b·

~

" 1

" "'~ e ." • . •

I~

I', .

.. .." •. ,.",. . :)

, .-

N

....~'f".,c', ~ _c. •• ··i t"'.,,,,~,. ,. 1, ~
•
,:

, •.

\ .- . ...

If! •~, I,.

.... 'I '

J . •

•

:-~.,

~. : .

<0,)"

,.\;,

,•• ... '"",' t..
~~'..,.';',..' ~:-,",'. . ':~c,I'. , 'f'.:. t'"
~ "
I"

• .•

j"

.

'

#'

.....

~

t'

I, l l,,'~ Jt.~· ·,,~: u

\I •

• i

•

2

•

3

4

5

6

811. Ginkgo tzagajanicathat these two species should be regarded as distinct until detailed informations are available on
leaves from Spitsbergen.
The extant Ginkgo biloba has small vein-density (13 to 16 per cm), and large amplitude ofcell-sinuosity (6 lim). Its periclinal walls of ordinary cells, though frequently swelled (PI. 67, Fig.
2), do not show any blunt papillae.
Trend in development of cuticular features
Some cuticular features of Cretaceous, Tertiary and extant Ginkgo species are summarized inTable 2. In general, decrease in development ofpapillae on the ordinary and subsidiary cells canbe recognized as follows. Three early Palaeogene
species, Ginkgo spitsbergensis, G. wyomingensis
and G. tzagajanica, are similar in cuticular features; each having the subsidiary-cell-papillae almost completely overarching the stomatal aperture, and ordinary-cell-papillae. Though thesecuticular features are observed in many Cretaceous species, such species usually show promiTable 2.

Cuticular features of Ginkgo species
since the Cretaceous. NCP: Normal
cell papillae, T: Trichomes, ACW:
Anticlinal cell walls, SCP: Subsidiarycell-papillae, x: Absent, solid circle:
Present, triangle: Present in restricted
area, wave (VI): Undulate, short line:
straight, solid square: Present but notoverarching the stomatal aperture,
asteriks: Present and overarching thestomatal aperture.
Upper cuticle
NCP

T

G.
G.
G.
G.
G.

bilobaadiantoides
occidentalis
gardneriorientalis

x
x
x

x
x
x
x
x

G.
G.
G.
G.

samylinae
spitsbergensis
wyomingensis
tzagajanica

x
x
x

x

G. pilifera
G. paradi antoi desG. pluripartita
G. coriacea
G. polaris

•
x

•
x

•x

•
•
•

x

x

•
•x

ACW

Lower cuticle
SCP

NCP

T

x
x

x
x

X
X

*•

•
x

•

•

**
*
**
**

•

x

•
•
•
•

••
••

x
x

x
X

x
x

•
•
•
•
•
x

351

nent papillae and trichome!. on the upper cuticle,
not seen in early Palaeogene species. Among theCretaceous species, Ginkgo paradiantoides described by Samylina (1967a) shows closest resemblance to the early Palaeogene species mentioned above.
From the Palaeogene of Sakhalin and Primorye, Ginkgo orientalis and G. samylinae havebeen known. These two species show less developed cuticular features compared with the three
early Palaeogene species discussed above. In these
two species, ordinary-cell-papillae are absent, andsubsidiary -cell-papillae, though present, do not
overarch the stomatal aperture. Pliocene recordsof the genus in Asia are known from Japan(Hikita, 1949; Iwao, 1978). They are identicalwith the extant Ginkgo biloba lacking both thesubsidiary- and ordinary-cell-papillae. Recently,
Kamada et al. (1981) reported the occurrence ofGinkgo biloba from the Plio-Pleistocene of Kyushu, Japan, which is the youngest fossil record of
the genus. Unfortunately, they did not describe
the cuticles of their specimens.
In Europe, so far as we know, the oldest Tertiary record of the genus is Ginkgo gardneri fromthe Eocene of Isle of Mull. Although it is very
different from other Tertiary or younger species
in the features of the upper cuticle, the lower
cuticular features of this species resemble otherearly Palaeogene species. Ginkgo gardneri israther close to the Cretaceous Ginkgo pluripartita (Shimper) Heer. The cuticles of the latter
species were described by Florin (1936) and
Brown (1975). In our opinion, Ginkgo gardneri
may represent phyletically different lineage fromother Tertiary species though the informations of
Palaeogene Ginkgo in Europe are still too scarce.
Ginkgo occidentalis possesses the subsidiary- andordinary-cell-papillae but the stomatal apertures
are not overarched. Records of Ginkgo species
without the subsidiary- and ordinary-cell-papillae
in Europe are known from the Miocene of Silesia(Szafer, 1961) and Pliocene of Frankfurt am
Main (Florin, 1936).
Concerning North American ginkgoes, thecuticular features of the Palaeocene Ginkgo
wyomingensis have already been introduced

Junji HORIUCHI and Tatsuaki KIMURA

352

earlier. Cuticular informations of the Eocene
and Oligocene Ginkgo are absent in North
America. A Miocene record given by LaMotte(1936) under the name of Ginkgo adiantoides(Unger) Heer does not show any papillae on theordinary and subsidiary cells.
Acknowledgements
J. Horiuchi wishes to express his sincere
thanks to Prof. Hisayoshi Igo of the Universityof Tsukuba for his helpful suggestions and giving
him the opportunity to carry out this study as apart of his Master Thesis. His thanks are also
extended to Profs. Naoaki Aoki and Hiroshi
Noda of the University of Tsukuba for theirkind suggestions.
This study was supported by the Grant-inAids for Scientific Researches from the Ministryof Education, Science and Culture of Japan(No. 59540499).
References
Brown, J. T. (1975): Upper Jurassic and Lower
Cretaceous Ginkgophytes from Montana.
Jour. Paleont., vol. 49, no. 4, p. 724-730.
Florin, R. (1936): Die fossil en Ginkgophyten
von Franz-Joseph-Land, nebst Erorterungenfiber vermeintlich Cordaitales mesozoischen
Alters. II. Algemeiner Teil. Palaeontogr. B,
Bd. 82, p. l---il8, pIs. l---il.
Givulescu, R. (1973): Die fossilen Koniferen
des Fundortes Chiuzbaia F. Geol. Inst.
Mem., vol. 19, p. 31-34, pIs. 11-15.
Harris, T. M., Millington, W. and Miller, J.
(1974): The Yorkshire Jurassic Flora, IV.
1 Ginkgoales, 2 Czekanowskiales. viii + 150

pp., 8 pIs., Brit. Mus. (Nat. His.), London.
Heath, O. V. S. (1975): Stomata. Oxford Biology
Readers, no. 37, p. 1-31.
Hikita, S. (1949): On the new localities andhabitat of Ginkgo biloba L. in Pliocene,
Japan. Kobutu to Chishitu, vol. 12, p. 1-6.
Iwao, Y. (1978): Late Cenozoic Ginkgo biloba
L. from the Hoshiwara Formation in Kumamoto Prefecture, Kyushu, Japan. Rep. Fac.
Sci. Engin., Saga Univ., no. 6, p. 45-50,
pI. 1.
Jordanov, D. and Kitanov, B. (1963): Einige
interessante fossilen Pflanzen aus dem
Pliozan in der Umgebung der Stadt Goze
Deltschev. An. Univ. Sofia (1961---il2), vol.
51, no. 1 (not cited).
Kamada, Y., Iwao, Y., Miyaki, M. and Okazawa,A. (1981): On the Hiradoguchi plant bed
discovered from Tabira-machi, Kitamatsuura-gun, Nagasaki Prefecture. Nagasakikenchigakukaishi, vols. 33/34, p. 11-28, pIs.
1-5 (in Japanese).
Kausik, S. B. (1974): The stomata of Ginkgo
biloba L., with comments on some noteworthy features. Bot. J. Linn. Soc., vol. 69,
p.137-146.
Krassilov, V. A. (1976): Tsagajan Flora of theAmur Province. Inst. Bioi. Pedol., Far East.
Sci. Centre, Acad. Sci. USSR, p. 1-92, pIs.
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Kimura, T. and Horiuchi, J. (1978): Pseudolarix
nipponica sp. nov., from the Palaeogene
Noda Group, Northeast Japan. Proc. Japan
Acad., Ser. B, vol. 54, no. 8, p. 429-434.
LaMotte, R. S. (1936): The Upper Cedarville
Flora of Northwestern Nevada and adjacent
California. In, Middle Cenozoic Floras ofWestern North America. Carnegie Inst.
Washington, Pub., 455, p. 57-142, pIs. 114.

Explanation of Plate 68
Figs. l---il.
SEM micrographs of Ginkgo tzagajanica Samylina (stage no. MISEM-l).
Fig. 1: External surface of a stoma of the lower cuticle. Note four lateral and two polar
subsidiary-ceIl-papillae overarching the stomatal aperture.
Fig. 2. Oblique view of the external surface of the lower cuticle showing length difference
between normal- and subsidiary-ceIl-papillae
Figs. 3-4: Internal surface of the boundary area of normal cells of the upper cuticle.
Fig. 6: A cross section of a lower cuticle.

HORIUCHI and KIMUR A: Ginkgo tz agajanica

Plate 68

1

2
3

4
5

811. Ginkgo tzagajanica
Lancucka-Srodoniowa, M. (1966): Tortonian
flora from the "Gdow Bay" in the South of
Poland. Acta Palaeobotanica, vol. 7, no. 1, p.
3-135, pis. 1-7.
Manum, S. (1966): Ginkgo spitsbergensis n. sp.
from the Paleocene of Spitzbergen and a
discussion of certain Tertiary species ofGinkgo from Europe and North America.
Norsk Polarinst. Arbok 1965, p. 49-58, pis.
1-2.
Medjulianov, V. A. (1969): Ginkgoites ex gr.
adiantoides from the Lower Paleogene ofSouth Sakhalin. In, Fossil Fauna and Floraof the Far East, I. Far East Geol. Inst.,

Komarov Far East Filial, Sib. Br., Acad.
Sci. USSR, p. 139-152, pis. 18-20 (inRussian with English summary).
Oishi, S. (1938): On the cuticles of Tertiary
Ginkgoites leaves from Kuji, Iwate Prefecture. Jour. Fac. Sci., Hokkaido Imp. Univ.,
Ser. 4, vol. 4, nos. 1-2, p. 103-106, pI.
13(1 ).
Pant, D. D. and Mehra, B. (1964): Developmentof stomata in leaves of three species of Cycas
and Ginkgo biloba L. J. Linn. Soc. (Bot.),
vol. 58, no. 375, p. 491-497, pI. l.
Polyshchnuk, L. V. (1975): Variation of epidermal characters of Ginkgo from the Palaeogene and Neogene of Primorye in respect toclimatic changes. In, Krassilov, V. A. (ed.):Fossil floras of the Far East. Inst. Bio. Ped.,Far East. Sci. Centre, Acad. Sci. USSR Proc.

Asahikawa (Asahigawa) MIll, Ibusuki

353

N.S., vol. 27, p. 76-83, pI. 5 (in Russianwith English abstract).
Sakisaka, M. (1958): Study of Ginkgo. 144 pp.
Kazama-shobo, Tokyo (in Japanese).
Samylina, V. A. (1967a): The Mesozoic flora of
the area to the west of the Kolyma River(the Zyrianka Coal-Basin) II. Ginkgoales,
Coniferales, General Chapters. Paleobotanika,
Leningrad, vol. 6, p. 133-175, pis. 1-14 (inRussian with English summary).
--(1967b): On the final stages of the historyof the genus Ginkgo L. in Eurasia. Jour. Bot.
Acad. Sci. USSR, Leningrad, vol. 52, no. 3,
p. 303-316, pis. 1-6 (in Russian withEnglish summary).
Sasa, Y. (1932): On the geology of Kuji District.
Jour. Geol. Soc. Tokyo, vol. 39, no. 466, p.
401-431; no. 467, p. 481-501; no. 468, p.
552-579 (in Japanese).
Seward, A. C. (1919): Fossil plants. vol. 4, 16+543 pp. Cambridge.
Shaparenko, K. (1935): Ginkgo adian to ides
(Unger) Heer; Contemporary and fossil
forms. Philip. Jour. Sci., vol. 57, no. I, p.
1-29, pI. l.
Szafer, W. (1961): Miocene floras from Stare
Gliwice in Upper Silesia. Inst. Geol., Prace,
vol. 33, p. 1-205, pis. 1-25.
Tralau, H. (1968): Evolutionary trends in thegenus Ginkgo. Lethaia, vol. 1, no. 1, p. 6310l.
Unger, F. (1845): Synopsis Plantarum Fossilium.
211 pp., Lipsiae (not cited).

mm, Kuji ~~, Nagasaki :R~. Noda !l!ffH. Tokyo **.

*~tjtl!nl:.)j1fi"t J., t1m=*!J!flfll\iflf¥~~i1EQ) Ginkgo t zagajanica Samylina- c <I:.-t
Q)j'j-jf}cRft*Q)!/'!fll&: ,{~·=FiJjI,~tl;f,Q) ;t:'P-lfi'1:iW:L1!!~I'::' 'J)-;(fi"tJ., !l!fm~lf¥~JI (i!t~=*""fffl)) tJ'l?(~ir{f-.Il!.~ftJ: Ginkgo :rtUt:.{i~f(tJ~I~l?nt.::. ~hl?Ll:.7l-jfjQ)~·~'MIiiLt.*~~'tJ~. it:~J\:to.t If ;&11(m)~ I'::' [g~ l?n 1.> 4·H:&tJ· l?
~ 'i'n ~ liIj-filiQ) lTIl-fl6j(~;ltfl.::.Ji.1H.-. Samylina(1967b) I:'.t ",,-c Bureja Basin Q)i':t~=*flrFiftltJ'I?~[].liIU~;hJ.:: Ginllgo tzagajanica cl'U

J.E~nJ.,.

~Q)fmLUl

nt. : : : <~:d'tJ,Q)f,\'l:;lq.::.M')t.::~ Q)L';b1.>tJ~. //"jijltm·I?~1.t.::~< Q)~*tJ. l?, Jif{~G+X:I:.)ffiIJll-t J., :::. c Q)L' ~ J.,~ <Q)ti'ft4itJ~A'f. ~ n. J: "" -C*fiJ!Q)~7JIJt\'W~tJ~ J: IJ~;ffijtJ: ~ Q) c tJ: "" t::. •.t,"jijltl~ l?n t::. Ginkgo ~Ht1 i Q))ut~~)l1Q)liJf'1l::tJ, l? -ttQ)~Q)I'j:l"C~) ffl)(,i:I;::. J: ') -cffi~tJ,fi,i(cIb l?
i t::.il§lf*ltfl*H:':to ~ '-C ~ )iJH"I)j;(l'~tdr!fi'AiiiQ);b 1.> ~ c tJ~FVJ l? tJ'l:' tJ: "" t::.. ~ l? I:'.
Ginkgo '!tQ)7l-tflljfj!l!l:to J: If*JUIt)l1lc:illo.,> l?nJ., 4\-jfjNlc"'?~ '-C. -t l?/Mt~jfjN c L..-C
C nt-:f't JtM~B/:H:' lf~JJl1:tJ,;b J., tJ'IC"'?~ '-C ~ifO C. {t:.E:l\1!:to J: lfm1=..:l\1!Q)t6i:~ftJ, l? m=*'CtJ.
Ilif.. ~t~~~J: I) ¥Ii$- ~nt::. Ginkgo jtQ)~&:Hlfj~Q)~rl3'i'I9~{t:.Q)IIM1Hc"'?~ '-c~ifO Ct::..

n.

n

WlJ*JIIIMf'l • *H~1jijTrans. Proc. Palaeont. Soc. Japan, N.S., No. 142, pp. 354-365, pIs. 69-73, June 30, 1986

812. A NEW SPECIES OF INOCERAMUS (CORDICERAMUS) (BIVALVIA)
FROM THE UPPER CONIACIAN (CRETACEOUS) OF HOKKAIDO*MASAYUKI NODA
Minami-Oita Junior High School, Oita

Abstract. In this paper, a new species Inoceramus (Cordiceramus) kawashitai
is established. The specimens were occurred from the Upper Coniacian of the Oyubari, Ikushumbets and Obira areas of Hokkaido. The variation of selected characters
are examined quantitatively on the basis of measurements and statistics, in addition
to traditional observation. The average relative growth of two relations (shell heightvs. shell length and shell height vs. breadth) are also examined. On the ground ofits considerably inflated equivalve shell, subquadt:ate or pentagonal marginal outline
and development of three radial ridges, this species is certainly assigned to the subgenus Cordiceramus. But the ontogenetic change of the certain characters does.not
agree with that of any known species. I point out the significance of the occurrenceof Cordiceramus from the Upper Coniacian of Japan, in that it represents the lower
part of the range of the subgenus. The phylogenetic relationships with allied species
are, however, put off, at present, as a further problem.

from a pebble in the sequence of the Zone of
Inoceramus mihoensis. On the other hand, in
1982, Mr. Kenji Sanada of Sapporo City collected some similar specimens with Kawashita's
collection from the pebbles of the PombetsGono-sawa. Next year, Matsumoto and I investigated the stratigraphy precisely with the helpof others along the Gono-sawa, and obtained still
more specimens from the middle part of theUpper Yezo Group. In this paper, these specimens are described under a new specific namewhich is dedicated to Mr. Yoshitaro Kawashita
in appreciation of kindness for offering a numberof specimens for this study.

Introduction
In 1980, a large specimen of Inoceramus was
unexpectedly obtained in a pebble of the Misojino-sawa, a tributary of the Ikushumbets River,by Mr. Yoshitaro Kawashita of Mikasa City. Its
peculiar form has attracted my interest. But it
has been very insufficient to establish a new
species, because the stratigraphic position is unknown. Subsequently he collected a specimen
with the same characters from a cliff of the rightbank of Penkehorokayuparo-zawa, about 50 m
upstream from the confluence with the YubariRiver. In summer of 1981, Matsumoto, Kawashita and I investigated the stratigraphy along
the Misojino-sawa and obtained a similar speci.
men with the former collection by Kawashita

Before going further, I express my sincere
thanks to Emeritus Professor Tatsuro Matsumoto of Kyushu University for his cordial guidance in the field and laboratory, useful advice
and critical reading of the typescript. I wish to
thank Messrs. Yoshitaro Kawashita, Takemi
Takahashi of Mikasa City, Kenji Sanada of Sap-

*Received February 2, 1985; revised manuscript
received April 9, 1985; read February 3, 1985
at University of Tokyo.
354812. A new species of Coniasian Inoceramidporo City, Shigehiro Uchida and Toshio Shimanuki of Iwamizawa City for their help in thefield work and for their kindness of offeringsome valuable specimens for this study. A partof the expense of this study was defrayed fromthe Shimonaka Commemorative Foundation(1984) and the Grant-in-Aid for Scientific Program (1984, No. 59916035), the Ministry of
Education, Science and Culture.

355

are also examined. The basic morphology andmeasurements are shown in Text-fig. 1.
For the measurements, the procedure ofstatistics and biometric analysis, see Hayami(1969), Hayami and Matsukuma (1971) andNoda (1975, 1983).
Palaeontological description
Family Inoceramidae Zittel, 1881

MethodGenus Inoceramus Sowerby, 1814

In addition to the traditional method, thestatistic analyses for some biometric characters
are examined, that is, the mean values of l/h,b/h and s/l and the angles a, (3, 1 and [), theirstandard deviations, Pearson's coefficient ofvariation and the ontogenetic change of selectedcharacters. The average relative growth of shellheight to shell length, and shell height to breadth

Subgenus Cordiceramus Seitz, 1961
For subgenus Cordiceramus, see Seitz (1961,
p. 110) and Noda (1979, p. 110, 114).
Inoceramus (Cordiceramus) kawashitai, sp. nov.

PI. 69, Figs. la-1d; PI. 70, Figs. 1a-2b;
PI. 71, Figs. 1a-3; PI. 72, Figs. 1a-2b;
PI. 73, Figs. 1a-5.

hText-fig. 1. Basic morphology for measurements.
h: shell height, I: shell length, H: maximum length from umbo to ventral extremity, ga: growth axis, b:breadth of right and left valves respectively, s: length of hinge-line, a: anterior hinge angle, (3: angle ofumbonal inflation, 1: posterior hinge angle, [): obliquity, angle between the growth axis and hinge-line,
Ra: anterior radial ridge, Rm: median radial ridge, Rp: posterior radial ridge.

356

Masayuki NODA

Types. -The repositories of the type specimens are as follows: KW: Yoshitaro Kawashita
Collection and JG: Jonan Geological Association, Oita. Holotype: KW2002, loco Y32, a cliffof the right bank of Penkehorokayuparo-zawa,
about 50 m upstream from the confluence with
the Yubari River, Oyubari area, Hokkaido. Sandy
siltstone bed, the middle part of the Upper Yezo
Group. Upper Coniacian. Paratypes: KW2001,
loco Ik9p, Misojino-sawa, a tributary of the Iku-

shumbets River, Mikasa area, Hokkaido. Stratigraphic position uncertain. KW2003, lower
reaches of Echinai-zawa, a tributary of the
Shimokinenbets River, Obira area, Rumoi-gun,
Hokkaido. JG.H2893, loco IklOp, Misojinosawa, in the sequence of the Zone of I. mihoensis, stratigraphic position precisely unknown.
JG.H2876-2892, locs. Ik2707, 2708, cliffs of
the left bank of the upper reaches of Gono-sawa(=Takiyoshi-zawa or Takino-sawa), a tributaryof the Pombets River, Mikasa area. Middle partof the Upper Yezo Group. The localities of the
Oyubari and Mikasa areas are shown in Text-figs.

?.._ _ _...:.t~m

Text·fig. 2. Map showing localities of Ino·
ceramus (Cordiceramus) kawashitai, n. sp. in the
Ikushumbets area (Mikasa area), Hokkaido. A:
Ikushumbets, B: Oyubari, C: Obira.

Text-fig. 3. The type locality of Ino·
ceramus (Cordiceramus) kawashitai, n. sp. in the
Oyubari area, Hokkaido.

Explanation of Plate 69
Figs. la-d. Inoceramus (Cordiceramus) kawashitai, sp. nov.
Paratype, KW2001, from loco Ik9p, floated nodule of the Misojino-sawa, a tributary of the
Ikushumbets River, Mikasa area, Hokkaido. Stratigraphic position uncertain (collected by
Kawashita, 1980). a: lateral view, b: dorso·lateral view, c: anterior view and d: dorsal view,
natural size.

NODA: A new species of Coniasian Inoceramid

Plate 691d

· 812. A new species of Coniasian Inoceramid357

2 and 3.
Material.-Twenty-one specimens are concerned with the description, of which 14 areused for measurements and statistics.
Diagnosis. -Shell of medium size, equivalve
or subequivalve and considerably inflated. Anterior part broad, abruptly bent from the flankand perpendicular to the valve plane. Marginal
outline subpentagonal to subquadrate. Winglike area developed with steep slope from themain part of the flank. Hinge-line long about
two thirds of shell length.
Surface ornamented with concentric ribs ofirregular intensity. Three ridges developed radially from the umbonal region. The anterior one
most prominent and demarcates sharply theanterior part from the flank, the median ridge
conspicuous along the growth axis in young
stage and gradually weakened with growth, andthe posterior one borders the posterior slope
and the main part of flank.
Description. -In general, either of two valvesis displaced dorso-ventrally along the commissureplane, giving consequently a superficially inequivalve aspect. For example, in the specimens

JG.H2876 (PI. 71, Figs. la-d) and 2877 (PI. 72,
Figs. la-d), the right valve is slided toward theventer, and the left umbo is considerably pro·
jected above the hinge-line; to the contrary, inthe specimens JG.H2883 (PI. 71, Fig. 2) and
2884 (PI. 72, Figs. 2a-b), the left valve is displaced toward the venter. The specimen JG.H2881(PI. 73, Fig. 5), which is not diplaced secondarily,shows clearly the equivalveness. As is demonstrated in Text-figs. 5 and 6, in some specimens(i.e., JG.H2877 and 2890), shell is considerably
inflated along the growth axis and antero-posteriorly in younger stages and gradually decreasing
its convexity with growth, whereas in the fullgrown individuals, such as KW2001 and KW2002,
the shell convexity changes abruptly at variable
growth stages. Umbo is terminal, considerably
curved inwards and forwards. Anterior part istruncated, broad, and bent angularly from themain part of the flank and concaved in itself,
forming an obtuse angle with the valve plane.
Postero-dorsal part inclined steeply, passing to
the wing-like area. The boundary between postero-dorsal and wing-like areas is comparatively
clear in the specimens KW2001 and 2002, but

A

B

b

1= 0.626 h 1.077

b=0.397h O. 997

r=0.9844

r =0.9359

100
90
80
70

1~2~0--L-'30---4~0--5~0~60~7~0~8~09TO~1~0~0----h~-.'2~-4~~--~~~~~~~-----------

20

30

40

5060708090100

h

Text-fig. 4A. Diagram showing the average relative growth of breadth to shell height in I. (C.)
kawashitai, n. sp. 4B: Diagram showing the average relative growth of shell length to shell height in I.
(C.) kawashitai, n. sp.

Masayuki NODA

358

in the specimens from Gono-sawa, that is,
JG.H2877, 2883, 2887, 2890, 2891, and 2892,
the two parts gradually pass from each otherwithout any sharp boundary.
Anterior margin is long and straight, forming
nearly a right angle with the ventral margin. In
younger individuals, such as JG.H2880, 2885,
2888 and 2890, the ventral margin is bent withan obtuse angle at about the center which corresponds to the end of the growth axis, and passed
gradually into a broadly rounded postero-ventral
margin. In the full grown individuals, such as
KW2001, 2002, JG.H2891 and 2893, the ventral
margin is nearly straight; postero-ventral margin

b/h

KW20QI

Kw2002

0.6

JG.H2"70.'r

1,1-----.. -.. .

0.'

Jr../
II

!"

0.'

iI'

... "

///

/'/
~._.i

0.1

10

20

30

"0

!liD

60

70

80

90

100

ITO

120

Hm",

Text-fig. 5. Diagram showing the ontogenetic change of shell convexity in l. (C.) kawashitai, n. sp.

narrowly curved and posterior margin forms anangle of about 100°-117° with the hinge-line
which is about two thirds of shell length on
average.
Concentric ribs are low, acute-topped, separated by concave interspaces, and generally irregular in intensity. In the umbonal region they
are fairly crowded but in some individuals much
weakened and hardly discernible. In some specimens (e.g., JG.H2877, 2891), minor concentric
rib lets are developed on the interspaces. Concentric ribs continue from the main part of flank to
the postero-dorsal slope, being gradually weakened on the wing-like area and hardly visible atnear the hinge. They are also comparable weakened on the anterior part. Three radial ridges run
from about 20 mm behind the umbo to the ventral margin. The anterior one is most prominentand demarcates sharply the boundary between
the flank and anterior region. The median one
runs along the growth axis, which is much conspicuous in the young shell of about 40 - 60 mm
in height, and it becomes weak gradually withgrowth and inclines somewhat posteriorly. The
posterior one is less conspicuous, demarcating
the postero-dorsal slope from the flank. Concentric ribs are bent at the intersections with theradial ridges. On some specimens (e.g., JG.H2876,
2877), many granular substances are scatteredirregularly on the inner surface of shell, which
may be pearl-like substance.
Biometry.-The measurements and biometriccharacters are shown in Tables 1 and 2, respectively. The relative growth between two relationshows generally allometric. In general, it is moresatisfactory that the allometric characters are

Explanation of Plate 70
Figs. 1a-2b. Inoceramus (Cordiceramus) kawashitai, sp. nov.
Figs. 1a-c. Holotype, KW2002, from loco Y37, a cliff of the right bank of the Penkehorokayuparo-zawa about 50 m upstream from the confluence with the Yubari River, 0yubariarea, Hokkaido. Stratigraphic posi.tion: middle part of the Upper Yezo Group (collectedby Kawashita, 1981). a: lateral view, b: anterior view and c: dorsal view, natural size.
Figs. 2a-b. Paratype, KW2003, floated nodule of the Echinai-zawa, a tributary of the
Shimokinenbets River, Obira area, Rumoi-gun, Hokkaido. Stratigraphic position uncertain (collected by Kawashita, 1981). a: lateral view, b: anterior view, natural size.

NODA : A new species of Coniasian Inoceramid

Plate 70

812. A new species of Coniasian Inoceramid

359

A

KW2001B

KW2002oI

3cm
I

Text-fig. 6. Cross section of I. (C. ) kawashitai, n. sp.
A: vertical section along the growth axis.
B: transverse section from anterior to posterior.
compared at a certain growth stage. However,on the present species, even if the allometriccharacters are examined under such a condition,
the numerical values calculated statistically would
not be so significant, because the shell convexity
and the marginal outline change abruptly at
various stages of growth. This allows us to summarize totally the characters regardless of thedifference in growth stage of the ex~mined
specimens.
The average relative growth is examined on
the two relations, shell height (h) versus shelllength (1), and shell height (h) versus breadth(b). (h) in abscissa and (I) and (b) in ordinate areplotted on logarithmic graph papers. The slopeof the reduced major axes (a) and also Y inter·
cepts (~) and the correlation coefficients (r) arecalculated, respectively. These are shown in
Table 3. Based on Table 3, the reduced majoraxes are demonstrated in Text-figs. 4a and 4b.
The growth indices (a), the null hypothesis of

isometry cannot be rejected considering thecorrelation coefficient and sample size (seeHayami and Matsukuma, 1971, p. 150-151).
The ontogenetic change of shell convexity
in the selected specimens is shown in Text-fig.
5. The transverse section and vertical section
along the growth axis of the same specimens aredemonstrated in Text-fig. 6.
Remarks.-As is evident from Text-figs. 5
and 6, the ontogenetic change of shell convexity
and the intensity of median ridge are closely
related to the changes of transverse section, vertical section and marginal outline. These characters are variable among individuals and withgrowth stages.
To sum up, the present species shows a considerable extent of variation not only in thebiometric characters but also in the characters
hardly examined numerically. As is clarified from
Table 2, the Pearson's coefficient of variation(u) of the angles a, ~, 'Y and 8, and a simple ratio

Masayuki NODA

360

Table 1. Measurements of Inoceramus (Cordiceramus) kawashitai, n. sp. linear dimension in mm.
bs

specimenv

h1

KW2001

R

121.2

115.0

58.6 88.0

KW2002

L

100.5

92.0

44.6

53.4 117°

KW2003

L

121.4

111.2

38.6

57.0

a

99°

r

b

l/h

s/l

b/h

68°

0.95

0.77

0.48

75° 100° 65°

0.92

0.58

0.44

68°

0.92

0.51

0.32

~

82° 105°98°

75° 118°

JG.H2876

R

52.3

45.7

18.9

-

116°

80°

-

7;·°

0.87

-

0.36

JG.H2876

L

52.5

45.7

25.0

-

117°

81°

-

74°

0.87

-

0.48

JG.H2877

R

67.5+

67.7

25.4 41.0

97°

80° 100°

68°(1.00-)

0.61

0.38

JG.H2877

L

85.0

67.7

30.4

41.0

97°

80°

76°

0.80

0.61

0.36

JG.H2879 L (119.3)(99.7)-

54.5(96°) (79°) 116° (77°) (0.84)(0.56)-JG.H2883

L

63.6

51.4

23.0

39.7

98°

78°

107° 72°

0.81

0.77

0.36

JG.H2885

R

51.4

36.3

18.0 25.0 115°

79°

98°

71°

0.71

0.69

0.35

JG.H2887

R

54.3

48.6

98°

81° 113°

70°

0.90

0.69

-

65°

0.84

0.73

0.33

68°

0.84

0.66

0.49

r---.

-

33.4

100°

R

37.4

31.6

12.5 23.0 109°83° 105°

JG.H2890 L

36.6

30.8

18.0 20.3 118°

78° 117°(97.3)(91.5) (26.5) 48.5 (118°) (87°) 109° (74°) (0.94)

JG.H2888

remarkscrushed~.

JG.H2893

R(0.53) (0.27) crushed

v: valve, h: shell height, I: shell length, b: breadth, s: length of hinge-line, a: angle between anterior
margin and hinge-line, /3: angle of umbonal inflation, 1: angle between posterior margin and hinge-line,
0: obliquity, angle between growth axis and hinge-line, l/h: simple ratio of shell length to shell height,
s/l: simple ratio of hinge-line to shell length, b/h: simple ratio of breadth to shell height, L: left valve,
R: right valve.
llh are all of small values, which indicate probably the stable characters for the species.
Every species assigned to Cordiceramus ischaracterized by peculiar marginal outline, convexity and surface ornamentations, which are, in
general, hardly expressed biometrically, howeverthese characters are rather important for the

specific criteria. Furthermore, the ontogenetic
change of these characters may be useful for theconsideration of phylogenetic relationships withallied species.
Comparison. -The young specimens of thepresent new species is similar to Inoceramus(Cord ice ramus) cordiformis purus Seitz, 1961,

Explanation of Plate 71
Figs. 1a-3. Inoceramus (Cordiceramus) kawashitai, sp. nov.
Paratypes, from loco Ik2708, upper reaches of the Pombets Gono-sawa (=Takiyoshi-zawa or
Takino-sawa), Mikasa area (Ikushumbets area), Hokkaido. Stratigraphic position: middle
part of the Upper Yezo Group (collected by Matsumoto, Uchida, Takahashi and Noda,
1983), natural size.
Figs. la-d. JG.H2876, closed valves, right valve displaced towards the venter along thecommissure plane. a: lateral view of right valve, b: lateral view of left valve, c: anteriorview and d: dorsal view.
Fig. 2. JG.H2883, closed valves, left valve displaced towards the venter along the commissure plane. Lateral view of left valve.
Fig. 3. JG.H2887, right valve.

NODA : A new species of Coniasian Inoceramid

Plate 71

361

812. A new species of Coniasian Inoceramid

Table 2. Biometric characters of Inoceramus (Cordiceramus) kawashitai, n. sp.
a

fl

r

(;,

l/h

5/1

b/h

1!.

12

12

12

12

10

10

11

..!!!..

106.6°

79.3°

107.3°

69.8°

0.875

0.662

0.369

5

9.41°

3.78°

7.24°

3.46°

0.06780.08370.0640

v

8.83

4.77

6.98

4.96

7.91

12.64

16.16

~: sample size, g!: mean value, !: standard deviation, !!: Pearson's coefficient of variation.

Table 3. Data of the average relative growth of Inoceramus (Cordiceramus) kawashitai, n. sp.

a

/3

log/3

h'

I'

1 and h

1.077

0.626

0.203441.844121.78268

T and h

0.997

0.397

0.40200

1.81984b'1.41165rN

0.9844140.935911

a: growth index (slope of the reduced major axis),~: Y intercept, it': mean of h' (h'=log h), 1': mean ofl' (l'=log 1), b: mean of b' (b'=log b), r: correlation coefficient, N: sample size.
from the Santonian of Henrichenburg, West
Germany, in the pentagonal margin with threeradial ridges, considerably inflated shell andweak concentric ornamentations but graduallydiffers from that subspecies with growth. For
instance, in the present new species the concentric ribs become more conspicuous and the
median radial ridge is weakened with growth.
The full grown specimen of this new species isclearly distinguished from that subspecies in its
subquadrate marginal outline and trapezoidaltransverse section.
The present new species also resembles 1. (C.)
cordiformis gravis Seitz, 1967, from the Middle
to Upper Santonian of Galdbeck and other areasin West Germany, in its much inflated shell,
ontogenetic change of the shell convexity, threeradial ridges, truncated anterior part and irregularsurface ornamentation, but discriminated fromthe subspecies in that its umbo is terminal, anterior margin nearly straight or slightly concave,the median and posterior ridges not so strong as
those of L. (C.) cordiformis gravis and the depression between the two radial ridges is inconspicuous.

The specimens from the lowest part of the
Middle Santonian of the Niobrara Formation,
Colorado were assigned to 1. (C.) cordiformis
and its affinity by Scott and Cobban (1964, pI.
7, figs. 1, 2; pI. 10, figs. 3, 5). Seitz (1965, p.
131) regarded these specimens as belonging toa group of 1. (C.) cordiformis with some comments. A specimen USNM 131513 (Scott andCobban, 1964, pI. 7, fig. 1) somewhat resembles
the specimens of the present species, but theAmerican specimen is clearly discriminated fromthose of the present species in the following
characters, that is, the anterior ridge is more
prominent, a radial groove runs somewhat
posteriorly along the anterior ridge, and a shallow depression developes between the medianand posterior ridges. Another specimen USNM
131514 also resembles the specimens of thepresent species but it differs from the latter in
its small beak angle (~=ca. 65°) and clearly demarcated posterior wing.
A specimen JG.H2884 which is somewhat
deformed secondarily, resembles the specimens
of Inoceramus emsti Heinz, 1928 (Woods, 1911,
text-fig. 45; Heinz, 1933, p. 250, pI. 19, fig. 1;

362

Masayuki NODA

1. deformis of Scott and Cobban, 1964, pI. 1, see
Seitz, 1965, p. 130; Troger, 1967, p. 128, pI. 14,
figs. 1--6) from the Coniacian of Europe, North
America and Madagascar in the weak radial
ridges, small beak angle and truncate anterior
region, but it differs from that species in its terminal umbo, and somewhat crowded and irregular concentric ornaments. Considering thesecondary deformation, the specimen seems to
be within the extent of variation of the present
species.
The present new species somewhat resembles
Inoceramus selwyni McLearn, 1926 (p. 122, pI.
21, figs. 8-9) from the Scaphites venticosus
Zone of the Smoky River Formation, Alberta,
Canada, in the anteriorly situated umbo, truncated anterior part, nearly straight or slightly
concave anterior margin and high outline, but the
Canadian species has a weak groove along the
growth axis, coarser concentric ornaments, circular ventral margin and no radial ridge.
The specimens JG.H2877 and 2887, which
are crushed diagonally towards the posteriorpart, resemble 1. (C.) brancoiformis Seitz, 1961
from the Upper Santonian of Recklinghausen,
West Germany, and also a specimen figured by
Scott and Cobban (1964, pI. 10, fig. 5). But itwould be superficial resemblance caused bysecondary deformation.
Inoceramus iburiensis Nagao et Matsumoto,1939 from the upper part of the Middle Turonian to the lower part of the Upper Turonian also
closely resembles the present new species, intransverse section at a certain stage of growth(see Matsumoto, 1981, p. 18, fig. 1; p. 20, fig. 3)
and higher marginal outline with nearly straight
ventral margin, but 1. iburiensis is inequivalve
and belongs to 1. (Inoceramus) and has muchcoarser concentric ribs and radial depression on
the flank and no radial ridge on the umbonal
region.
The young specimen of the present new
species is similar to Inoceramus yuasai Noda,
1974 from the Campanian of Shikoku in theanteriorly placed umbo, pentagonal margin,
abrupt change of shell convexity and the presence of radial ridges. 1. (C.) kawashitai is distinct
from the latter in its more inflated umbonal
region which has weaker ornaments, small angleof a and 'Y, less obliquity and subquadrate outline in the adult stage.
Occurrence.-l, Loc. Y32, Penkehorokayuparo-zawa, Oyubari area, Hokkaido. Zone of 1.
mihoensis, Upper Coniacian, associated withsmall individuals of Mytiloides, Gaudryceras sp.
and Damesites sp. Stratigraphic position: Middle
part of the Upper Yezo Group (for stratigraphy,
see Matsumoto, 1942, and Matsumoto and Haraguchi, 1978). 2. Locs. IK9p and IK10p, Misojinosawa, Ikushumbets area, Hokkaido. In the sequence of the Zone of 1. mihoensis of the Upper
Coniacian (Matsumoto, 1977). Stratigraphic posi~tion: precisely unknown. 3. Loc. 3p. Okumatazawa, Ikushumbets area. Together with the pebbles containing Inoceramus amakusensis Nagao
et Matsumoto which is a zonal index of theLower Santonian of Japan (Matsumoto, 1977).
Stratigraphic position: uncertain. 4. Locs.

Explanation of Plate 72
Figs. 1a-2b. Inoceramus (Cordiceramus) kawashitai, sp. nov.
Paratypes, from locs. Ik2707, 2708, upper reaches of the Pombets Gono-sawa (=Takiyoshizawa or Takino-sawa), Mikasa area, Hokkaido. Stratigraphic position: middle part of theUpper Yezo Group, natural size.
Figs. 1a-d. JG.H2877 from loco Ik2708, closed valves, right valve displaced towards theventer along the commissure plane. a: lateral view of left valve, b: lateral view of rightvalve, c: anterior view and d: dorsal view (collected by Sanada, 1982).
Figs. 2a-b. JG.H2884 from loco Ik2707 somewhat higher than Ik2708, closed valves, left
valve displaced towards the venter along the commissure plane. a: lateral view of rightvalve, b: lateral view of left valve (collected by Matsumoto, Uchida, Takahashi and Noda,
1983).

NODA : A new species of Coniasian Inoceramid

Plate 72

812. A new species of Coniasian Inoceramid
Ik2707 and 2708. Upper reaches of the PombetsGono-sawa (Takiyoshi-zawa or Takino-sawa),
Ikushumbets area. Zone of 1. mihoensis, Upper
Coniacian, associated with 1. mihoensis and
1. (P.) yubariensis. Stratigraphic position: Middle
part of the Upper Yezo Group (for stratigraphy,
see Matsumoto, 1984, and Matsumoto andNoda, 1985). 5. Echinai-zawa, Obira area,
Hokkaido. Stratigraphic position: uncertain.
Conclusion
To sum up, the present new species, Inoceramus (Cordiceramus) ka wash itai, is not identical with any other allied species previously described so a new species is established in thispaper and the specific name is dedicated to Mr.
Yoshitaro Kawashita.
The occurrence of numerous specimens of thespecies from the Upper Coniacian is very significant not only as the zonal index of that stage but
also to consider the phylogeny of the subgenus
Cordiceramus because the present occurrence
represents a lower part of the range of the subgenus as Kauffman (1977) pointed out.
Noda and Matsumoto (1976) have alreadyshown the range of I. cordiformis from Japan
without palaeontological description, but it isnecessary to describe more clearly the taxonomy
and succession of 1. (Cordiceramus) species ofJapan. This is beyond the scope of the present
paper.
References
Hayami, I. (1969): Mensuration of fossils andstatistics - An example of palaeontological
exercise -. Sci. Repts., Dept. Geol., Kyushu
Uniu., vol. 10, no. 2, p. 67-90 (in Japanesewith English abstract).
--and Matsukuma, A. (1971): Mensuration offossils and statistics - Analysis of allometry
and variation -. Ibid., vol. 10, no. 3, p. 135160 (in Japanese with English abstract).
Heinz, R. (1928): Das Inoceramen Profil deroberen Kreide Llineburgs. Mitt Anflihrung
der neuen Formen und deren Kennzeichnung. Jber. Nieders. Geol. Ver., vol. 21, p.

363

63-81, pis. 1-2.
--(1933): Inoceramen von Madagaskar undihre Bedeutung fUr die Kreidestratigraphie.
Z. deutsch. geol. Ges., Vol. 85, p. 241-259.
Kauffman, E. G. (1977): Systematic, biostratigraphic and biogeographic relationships between Middle Cretaceous Euramerican andNorth Pacific Inoceramidae. Mid-Cretaceous
Event - Hokkaido Symposium, 1976 -.
Palaeont. Soc. Japan, Special Papers, no. 21,
p.196-212.
Matsumoto, T. (1942): Fundamentals in the
Cretaceous stratigraphy of Japan. Part 1.
Mem. Fac·. Sci., Kyushu Imp. Uniu., Ser. D,
vol. 1, no. 3, p. 129-280, pis. 5-20.
- - (1977): Zonal correlation of the Upper
Cretaceous in Japan. Mid-Cretaceous Events- Hokkaido Symposium, 1976 -. Palaeont.
Soc. Japan, Special Papers, no. 21, p. 6374.
--(1981): The specimens of Inoceramus(Bivalvia) donated to the Kitakyushu Museum of National History. Bull. Kitakyushu
Mus., Nat. Rist., no. 3, p. 15-26, pis. 2-5(in Japanese with English abstract).
--(1984): The so-called Turonian-Coniacianboundary in Japan. Bull. Geol. Soc. Denmark, vol. 33, p. 171-181.
- - and Haraguchi, Y. (1978): A new texanitine
ammonite from Hokkaido (Study of Cretaceous ammonites from Hokkaido andSaghalien 34). Trans. Proc., Palaeont. Soc.
Japan, N.S., no. 110, p. 306-318, pI. 42.
- - and Noda, M. (1985): A note on an inoceramid species (Bivalvia) from the Lower
Coniacian (Cretaceous) of Hokkaido. Ibid.,
no. 140, p. 263-273, pIs. 41-44.
McLearn, F. H. (1926): New species from theColoradoan of Lower Smoky and Lower
Peace Rivers, Alberta. Nat. Mus. Canada,
Geol. Ser., no. 45, p. 117-126, pis. 20-23.
Nagao, T. and Matsumoto, T. (1939): A monograph of the Cretaceous Inoceramus ofJapan. Part 1. Jour. Fac. Sci., Rokkaido Imp.
Uniu., Ser. 4, vol. 4, nos. 3-4, p. 241-299,
pis. 23-34.
Noda, M. (1974): A new' species of Inoceramus
from the Shimantogawa Group of south
Shikoku. Trans. Proc. Palaeont. Soc. Japan,
N.S., no. 93, p. 240-248, pI. 34.
(1975): Succession of Inoceramus in the364

Masayuki NODA

Upper Cretaceous of Southwest Japan. Mem.
Fac. Sci., Kyushu Univ., Ser. D, vol. 23, no.
2, p. 211-261, pIs. 32-37.
__ (1979): Nomenclatorial survey on Inoceramus balticus Bahm and related species.
Fossils, no. 29, p. 107-121, pIs. 1, 2 (inJapanese).
--(1983): Notes on so-called Inoceramus
japonicus (Bivalvia) from the Upper Cretaceous of Japan. Trans. Proc., Palaeont. Soc.
Japan, N.S., no. 132, p. 191-219, pIs. 4146.
--and Matsumoto, T. (1976): Atlas of Japanese Fossils, 45, Mesozoic molluscan fossilsof Japan 4 (Cretaceous Inoceramus 1-6).
24 pp. (in Japanese), Tsukiji-Shokan, Tokyo.
Scott, G. R. and Cobban, W. A. (1964): Stratigraphy of the Niobrara Formation at Pueblo,
Colorado. U.S. Geol. Surv. Prof. Paper,
454-L, L1-L30, pIs. 1-11.

Seitz, O. (1961): Die Inoceramen des Santon von
Nordwestdeutschland. Beih. Geol. Jb., vol.
46, p. 1-186, pIs. 1-15.
--(1965): Die Inoceramen des Santon und
Unter Campan von Nordwestdeutschland.
Teil. II. Ibid., vol. 69, p. 1-194, pIs. 1-26.
__ (1967): Die Inoceramen des Santon und
Unter Campan von Nordwestdeutschland.
Teil. III. Ibid., vol. 75,p.1-171,pls.1-27.
Trager, K. A. (1967): Zur Paliiontologie, Biostratigraphie und faziellen Ausbildung derunteren Oberkreide (Cenoman bis Turon).
Teil I. Paliiontologie und Biostratigraphie
der Inoceramen des Cenomans bis Turons
Mitteleuropas. Abh. Staatl. Mus. Mineral.
Geol., vol. 12, p. 13-207, pIs. 1-14.
Woods, H. (1910-1911): A monograph of theCretaceous Lamellibranchia of England.
Palaeontgr. Soc. Mon., London, vol. 2, part7, Inoceramus. p. 261-284, pIs. 44-50;
part 8, Inoceramus. p. 285-340, pIs. 51-54.

Echinai-zawa :x. 7" T -( iR, Gono-sawa :n:.roiR, Ikushumbets ~$5JIJ. Iwamizawa ¥r J!iR, Kitakyushu ~t:fl:H'i. Mikasa =:¥E, Minami-Oita m:k~, Misojino-sawa =:-n~roiR, Obira 'J'f, Obira·shibe 'J'f~, Oita :k~, Oyubari :k&iJlf, Penkehorokayuparo-zawa ....:.:/ 'r;f; P 7J =z. g ... ~ p iR,
Pombets ~5JIJ. Rumoi-gun Wliln1l!l, Sapporo fL~, Shimantogawa 1?97J+JII, Shimokinenbets "fre;t.5]Ij, Takino-sawa jtroiR, Takishita ifi"f, Takiyoshi-zawa ilt!i1fiR, Yezo :x. ,/, Yubari &iJlf.

Explanation of Plate 73
Figs. 1-5. Inoceramus (Cordiceramus) kawashitai, sp. nov.
Paratypes from locs. Ik2707, 2708, upper-reaches of the Pombets Gono-sawa (=Takiyoshizawa or Takino-sawa), Mikasa area, Hokkaido. Stratigraphic position: middle part of theUpper Yezo Group, natural size.
Fig. 1. JG.H2891 with weak radial ridges.
Fig. 2. JG.H2888.
Figs. 3a-b. JG.H2890, a: lateral view, b: anterior view.
Fig. 4. JG.H2885 showing the regular, somewhat crowded concentric ribs.
Fig. 5. JG.H2881, closed valves, anterior view showing the equivalveness. Posterior halferoded out (collected by Matsumoto, Uchida, Takahashi and Noda, 1983).
Figs. 6a-;:. Inoceramus (Cordiceramus) sp. cf. I. (C.) kawashitai, sp. nov.
JG.H2901, from floated nodule in the Obirashibe River, at Takishita, Obira area, Hokkaido.
Stratigraphic position uncertain, xO.8. a: left valve, b: right valve,c: posterior view showing
the equival·veness (collected by Shimanliki, 1984).

NODA: A new species of Coniasian Inoceramid

Plate 73

812. A new species of Coniasian Inoceramid

365~ti'iaJH:I =-7 "/'7 ",ml:t,'f\iI'I?2iI1±I Lt.: Inoceramus (Cordiceramus) II)tT:flb:::.'0\"-C:~t$JH:kt>'~, ~~Zlj. 'J':iJZ!1!!~t.::.lil±l-r 7.:> :I =-7 "/'7 ",ml:Iff\II)Jt!!lfiil' 1?a:1±I Lt.: Inoceramus t'::'lt~;b.lb-C¥.fti&;!;7.:>Mtm~~-r~ lI)iI';!;7.:> • .:tLt.::.'0\"-C. ?t*II)Wf~:1J7*t.::.:hn.::t-c,1o.¥JiJllj~~I¥J'F7*t.::. J: IJ. \" < '0i1,II)M'l!tIl)~~~:iJZ~:m%tUll;~II)~W~lli\~t.:. -tIl)*5*.
~~tJ: \" Llt~~t.::.i1i <. :k ~ td~I?~. gg)llMi t.:lt:n:jl]MII)~iI' <. :ljUf~t'::'ge~-r 7.:> 35k1l)~tJ: c·li Inoceramus lI)iIfiJ\ft Cordiceramus 1I)~;;:I:;:fi-C;!; 7.:> I. (C.) cordi/ormis Sower·by 1I)¥.fti&t.::.~JiJi-r 7.:>,l'.\iI'~\' 'il'. Ji~:fi c ~*HIt.::.J:ti\OC-r 7.:> c ~. UlI;~t.::. c ~ tJ: ? ~iI' < ~~~1I)~1ttJ:
tL i -Ct.::.~ I?tLkfiiJtLlI):fit.::. ~ ~~ LtJ:\' 'II)-C. .:.: t.::.tT:fi c L -C~.-r 7.:>.
:fi15 I noceramus (Cordiceramus) kawashitai It*Wf~t.::. thbJJ\' ,t.: t..: \"k)llrEl3:;t~~~t.::.i'Ii!:
15 Lt.: ~ II)-C;!; 7.:>. *:fi It ~t$;g~!1!! 11):1 =- 7 "/'7'" ml:lff\iI'l? Inoceramus mihoensis
Matsumoto ~ I. (Platyceramus) yubariensis Nagao et Matsumoto I'::'c ~tJ:-:>-C~a:-r7.:>II)-C, -Ff*, ftl!1I)Jt!!~iI' I? ~ ~IDE~tL7.JtJ: I? Ii, 1pmtJ:1iH~~1t::fi II) 1'0 c tJ: 7.:> .: c iI'Wl~ ~tL7.:>. it.:. *:filt Cordiceramus c L-Clta:I±IJ§$iI'ii<. -t1l)*~~1o.~~~-r7.:>l:t.::.

c. .:1fi:~-C;!; 7.:> ii',.: tLt.::. '0\"-Clt*M1i,"('It.M1i1it1!ti', -t1l)~W~A,:f:&t.::.~;tJ.t.:.

JfEBfltz

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 142, pp. 366-392, pIs. 74-77, June 30,1986

813. LOWER CRETACEOUS BIVALVES FROM THE SAKAWA AREA, SHIKOKUMASAYUKI TASHIRO
Department of Geology, Faculty of Science, Kochi University
andTOMOKO MATSUDA
Dojimaru, Wakamatsu, Kitakyushu City, Fukuoka

Abstract. This paper deals with the description of bivalve fossils from theLower Cretaceous System of the Sakawa area, Shikoku. Thirty-three species of 24
genera, including four new species, i.e., Cosmetodon tomochiensis, sp. nov., Paruamussium tosaense, sp. nov., Paruamussium kattoi, sp. nov. and Protocardia(Protocardia) amanoi, sp. n'ov., are described from various localities in this area.
The bivalve fauna of the Bunjo Formation is nearly identical with that of the
Aptian Hagino Formation of the Monobe area, Shikoku. Judging from the bivalve
fauna and associated ammonites, the Yotsushiro Formation and the upper memberof Tosakamo Formation are closely similar in their faunal compositon to each otherand are probably correlated with the upper part of the Hibihara Formation (mainly
Albian) of the Monobe area. The faunas of the lower member of Tosakamo Formation and Kurohara Formation closely resemble that of the lower part of the Hibihara Formation (mainly Aptian), having many common species among them.
Although the geological age of the lower member of Tosakamo Formation, inclusive of the Kurohara Formation, is suggested at the Apitan and nearly the same as
the presumable age of the Bunjo Formation, the bivalve fauna of the Bunjo Formation is quite different from that of the lower member of Tosakamo Formation
except for the occurrence of several worldwide bivalve species and ammonites. The
difference is probably due to ecological dissimilarity between them.

has not been achieved sufficiently. Recently wehave obtained many specimens of bivalves fromvarious localities of the Lower Cretaceous strata
in this area. In addition to them, numerous specimens have been supplied to us by Dr. J. Katto of
Kochi. Through the study of these materials 33
species under 24 genera of bivalves are distinguished. After the systematic description, we give
remarks on the biostratigraphical implications of
the faunas.
Before going further we wish to, express ourIntroduction
Sakawa in Kochi Prefecture, central Shikoku
is well known for the Mesozoic geological investigations. The Cretaceous System of the Sakawa
area has hitherto been treated stratigraphically,tectonically and palaeontologically by many
authors. The palaeontological study, however,Received February 18, 1985; revised manuscript
received April 10, 1986; read January 24, 1982
at University of Tokyo.
366

813. Cretaceous bivalves from Sakawa

sincere thanks to Prof. Emer. Tatsuro Matsumotoof Kyushu University for his reading the firstdraft of this paper, and giving valuable suggestions. We would like to express our hearty thanks
to Prof. Emer. Jiro Katto of Kochi University
for his supply of numerous specimens for ourstudy and also to Mr. Masafumi Ito of Nara, for
his kindness of several geological informations
on this area for this study.
The specimens described in this paper are
kept in the Department of Geology, Kochi University (KSG).
Geological setting
The Lower Cretaceous System of the Sakawa
area consists of the Kaisekiyama (Aptian), Tosakamo (Aptian to Albian), Kurohara (Barremianto Aptian), Yotsushiro (mainly Albian), and Bunjo (Aptian) Formations (see Text-fig. 1; also see
Tashiro, 1985). The lower member of Tosakamo
Formation and Kurohara Formation are com-367

posed mainly of sandstone, and characterized by
the occurrence of shallow marine bivalves. The
former is distributed narrowly in the westernpart of the Sakawa basin, with the general trendof N 80°E. It is in fault contact with the Jurassic
Torinosu Group (the belt of Kamo area) on thesouthern side and conformably overlain by theupper member of Tosakamo Formation. The
latter is distributed in the northern part of the
Sakawa basin, with the same trend as the Tosakamo Formation. It is in fault contact with the
Paleozoic(?) strata on the northern side andis conformably covered by the Yotsushiro
Formation on the southern side. Yotsushiro
Formation is mainly composed of dark-gray siltstone and characterized by the occurrence ofpure marine bivalves and ammonites. The upper
member of Tosakamo Formation is also composed mainly of dark-gray siltstone, and several
beds of conglomerate, about 50 m in each thickness, are intercalated in the lower part. Somepure marine bivalves and ammonites occur from

VOTSUSHIRO

--r

rrm
§

F

E

[[]] 0a- -- C

B[J. .
.......
'SAKAWAo KOCHIo~A
0/~MONOBE
TOSA

BAY

\/

SAKAWA

KAMO

Text-fig. 1. Map showing the Cretaceous strata of the Sakawa Basin.
A: Kaisekiyama Formation, B: Kurohara Formation, C: lower member of Tosakamo Formation (="Kaisekiyama Formation" by Katto and Tashiro, 1981), E: upper member of Tosakamo Formation (="Yotsushiro Formation" by Katto and Tashiro, 1981; "Yunoki Formation" by Yamashita, 1961), F:
Yotsushiro Formation, D: Bunjo Formation, X: fossil localities.

368

Masayuki TASHIRO and Tomoko MATSUDA

the siltstone.
The Bunjo Fonnation is characterized by theoccurrence of many shallow marine bivalves fromits fine- to medium-grained arenite sandstone,
and intercalated narrowly between the Yotsushiro and Tosakamo Formations in the central
part of the Lower Cretaceous area, bounded byfaults on both northern and southern sides. The
Kaisekiyama Fonnation is exposed very narrowly
on and near the Kaisekiyama hills of Kamo in
Sakawa, composed of coarse-grained sandstone
and conglomerate, and contact with the "Paleozoic" strata on the northern side and with theTorinosu Group on the southern side. Several
non-marine or brackish water species were reported from this fonnation by Kobayashi and
Suzuki (1939) and Hirata (1974).
The Yamanokami Fonnation (not treated inthis paper) is also very narrowly limited tothe south of Torinosu, surrounded by the preCretaceous rocks, bounded by the faults. Shallow
marine bivalves, e.g., Pterotrigonia (Pterotrigonia) pocilliformis (Yokoyama), Nipponitrigonia
convexa Kobayashi, N. sakamotoensis (Yehara)
and Rutitrigonia yeharai Kobayashi et Nakano,were described from the sandstone by Kobayashi(1957), and Kobayashi and Nakano (1957).
Systematic description
Class Bivalvia
Subclass Palaeotaxodonta
Order Nuculoida Dall
Superfamily Nuculacea Gray, 1824
Family Nuculidae Gray, 1824
Genus Nuculopsis Girty, 1911
Subgenus Palaeonucula Questedt, 1930
Nuculopsis (Palaeonucula) ishidoensis(Yabe et Nagao)

PI. 74, Figs. 1-3.
1926. Nucula ishidoensis Yabe et Nagao, in

Yabe, Nagao and Shimizu, Sci. Rep.,
Tohoku Imp. Univ., Ser. 2, vol. 9, no. 2,
p. 41, pI. 13, figs. 46-47.

1965. Nuculopsis(Palaeonucula) ishidoensis(Yabe et Nagao); Hayami, Mem. Fac. Sci.,
Kyushu Univ., Ser. D, vol. 15, no. 2, p.

234.
1972. Nuculopsis(Palaeonucula) ishidoensis(Yabe et Nagao); Shikama and Suzuki,
Sci. Rept., Yokohama Nat. Univ., Ser. 2,
vol. 19, pI. 4, figs. 5-6.
1975. Nuculopsis (Palaeonucula) ishidoensis(Yabe et Nagao); Hayami, Univ. Mus.,
Univ. Tokyo, Bull., no. 10, p. 20.
1980. Nuculopsis (Palaeonucula) ishidoensis(Yabe et Nagao); Hayami in Hayami andOji, Trans. Proc., Palaeont. Soc. Japan,
N.S., no. 120, p. 423, pI. 51, figs. 1-6.

Materials:-KSG 3479-KSG 3480, externalmoulds, from Ujidani of Kamo, Sakawa; KSG
3481-KSG 3482, internal moulds from the same
locality.
Measurements (in mm.):ThickSpecimens
Length Height ness

KSG 3479, I. ex. mol.
KSG 3480, ditto
KSG 3481, I. in mol.
KSG 3482, ditto

10.0
10.1
11.3
11.0

7.0
7.2
8.4
8.0

1.5
2.0

Remarks:-The specimens from the lower
member of Tosakamo Fonnation are safely identified with Nuculopsis (Palaeonucula) ishidoensis(Yabe et Nagao) (Yabe, Nagao and Shimizu,
1926), from the Ishido Formation of Kwanto,
judging from the smooth inner margin and numerous fine concentric striae on the disk. This
species was also described from the Choshi
Group of Kwanto (Hayami in Hayami and Oji,
1980).
Occurrence and geological age :-Common in
medium grained sandstone of the lower memberof Tosakamo Formation at Ujidani of Kamo,
Sakawa area (Loc. 4); Aptian.

Superfamily Nuculanacea Adams et Adams
Family Nuculanidae Adams et Adams, 1858
Genus Portlandia Morch, 1857
Portlandia sanchuensis (Yabe et Nagao)

PI. 74, Figs. 4-7.

813. Cretaceous bivalves from Sakawa

369

1926. Nuculana sanchuensis Yabe et Nagao, in
Yabe, Nagao and Shimizu, Sci. Rep., Tohoku Imp. Univ., Ser. 2, vol. 9, no. 2, p.
42, pI. 12, figs. 21-23.
1965. Nuculana (s.l.) sanchuensis Yabe et
Nagao; Hayami, Mem. Fac. Sci., Kyushu
Univ., Ser. D, vol. 15, no. 2, p. 235.
1975. Nuculana sanchuensis Yabe et Nagao;
Hayami, Univ. Mus., Univ. Tokyo, Bull.,no. 10, p. 24.
1980. Portlandia (s.l.) sanchuensis (Yabe et
Nagao); Hayami, in Hayami and Oji,Trans. Proc., Palaeont. Soc. Japan, N.S.,
no. 120, p. 425, pI. 51, figs. 7-10.

Materials:-KSG 3483 - KSG 3484, internalmoulds from Ujidani of Kamo, Sakawa; KSG
3485 -KSG 3486, external moulds from thesame locali ty.
Measurements (in mm.):ThickSpecimens
Length Heightness

KSG 3483, I. into mol.
KSG 3484, r. into mol.
KSG 3485, r. ext. mol.
KSG 3486, r. ext. mol.

12.3
13.2
13.9
18.5

8.0
9.0
8.9
9.8

3.3
3.9

Remarks:-The specimens in our hands arereferable to Portlandia (s.l.) sanchuensis (Yabe et
Nagao) which has been precisely redescribed byHayami (in Hayami and Oji, 1980), from the
Choshi Group of Kwanto. The typical species ofthis species is known from the Ishido Formationof Kwanto (Yabe, Nagao and Shimizu, 1926, pI.
12, fig. 21).
Occurrence and geological age:-Rare in themedium-grained sandstone of the lower memberof Tosakamo Formation at Ujidani of Kamo,
Sakawa area (Loc. 4); Aptian.

Subclass Pteriomorphia
Order Arcoida
Superfamily Arcacea Lamarck, 1809
Family Parallelodontidae Dall, 1898
Subfamily Parallelodontinae Dall, 1898
Genus Cosmetodon Branson, 1942
Cosmetodon tomochiensis, sp. nov.

Text-fig. 2. The diagramatic sketches of
Cosmetodon tomochiensis Tashiro et Matsuda,
sp. nov., from the Tomochi Formation at Kashiwagawa of Tomochi, Kumamoto Pref. (scale 5
mm).
PI. 74, Figs. 9-15, PI. 76, Fig. 4, Text-fig. 2.
Materials:-Holotype, KSG 3487, internalmould of left valve, from Kashiwagawa of Tomochi, Kumamoto Prefecture, Kyushu; paratypes,
KSG 3488 - KSG 3489, internal moulds, fromthe same locality of holotype; KSG 3490-KSG
3491, external moulds, from the same locality;
paratypes, KSG 3492 - KSG 3493, internalmoulds, from Kuroishi of Kamo, Sakawa.
Diagnosis:-Shell small, tapering to anterior,
longer than high; umbo prosogyrate, located anteriorly; surface ornamented with numerous
radial ribs and laminated concentric striae; radialsulcus weak; hinge plate elongated with typicalparallelodontid hinge teeth.
Descrip tion :-Shell elongately su bquadrate,
expanded to posterior, tapering to anterior,moderately inflated; umbo prosogyrous, prominent but small, pointed at about one fourth fromfront of valve; dorsal margin nearly straight with
about two thirds of valve length, shorter in its

Masayuki TASHIRO and Tomoko MATSUDA

370

anterior segment than in posterior one with proportion of 1:3 in length; anterior margin slightly
arched, subvertically truncated from dorsal
margin; ventral margin weakly arched on posterior and anterior parts but weakly concave incentral part; posterior margin nearly straight or
weakly concave, obliquely truncated from dorsal
margin; postero-ventral margin narrowly rounded; surface ornamented with numerous flattopped radial ribs broader than their interspaces; numerous laminated concentric striae
well developed on surface but weaker and more
widely spaced than radial ribs; a weak radialsulcus extends from umbo to a point about one
third from front of ventral margin; posteriorcarinal ridge weak but well elevated; dorsal
carina indistinct; ligamental area very narrow
with very asymmetrical triangular outline; hinge
plate elongated with about 14 taxodont teeth ofwhich about 6 teeth under umbonal part small,divergent; 3 on anterior segment of plate elongated, obliquely situated; about 5 on posterior
segment very elongated, nearly horizontal; inner
margin smooth; adductor scars very weakly impressed.
Measurements (in mm.):Specimens
KSG 3487, r. into mol.
KSG 3488, I. into mol.
KSG 3489, I. into mol.
KSG 3492, r. into mol.

Length Height
8.6
9.8
9.6
7.8

5.0
5.3
5.2
5.2

Observation:-Although two specimens fromthe Tosakamo Formation are somewhat deformed, they are safely identified with the typespecimens from the Tomochi Formation in
Kumamoto Prefecture of central Kyushu, because of common features of hinge teeth andsurface ornamentation. On the posterior carinal
part of the disk, the radial ribs and concentricstriae of the Tosakamo specimens are generally
stronger than those of the other part of the disk.
Fine and numerous radial striae sometimes
appear on the inner surface over the pallial line.
The ligament grooves are indistinct.
Comparison :-This species resembles Parallelodon (Torinosucatella) kobayashii (Tamura, 1959)(Hayami, 1975) from the Jurassic of southern
Kyushu, in the surface ornamentation and theoutline which is tapering to anterior, but differsfrom the latter clearly in its weaker radial sulcus
and concentric striae. Cosmetodon nipponica(Nagao), from the Miyako Group of northeast
Japan (Hay ami , 1975), is easily discriminatedfrom this species in its obsolete or disappearedradial ribs on the surface, and horizontal anterior
teeth.
Occurrence and geological age :-Rare in thedark-gray siltstone of the upper member of the
Tosakamo Formation at Kuroishi of Kamo,
Sakawa area (Loc. 6); Albian: Rare in the darkgray shale of the Tomochi Formation at Kashiwagawa of Tomochi, Kumamoto Prefecture,
Kyushu; Upper Aptian or ?Lower Albian.
Genus Nemodon Conrad, 1869
Nemodon sp.

PI. 74, Fig. 8.
1957b. Nemodon (?) sp.; Amano, Kumamoto
Jour. Sci., Ser. B, vol. 2, no. 2, p. 84,
pI. 1, fig. 8.
Materials:-KSG 3494, internal mould of left
valve and several fragmental external moulds,
from Bunjo of Ochi, Sakawa.
Remarks:-KSG 3494 is 15.0 mm length and
8.0 mm high. This species is characterized by theelongated and subhorizontal hinge teeth on theanterior and posterior segments of the hinge
plate and the diverging small teeth in central partof the plate. The radial ribs on the surface are
weak but distinct. This species is identical with
Nemodon (?) sp. from the Hagino Formation in
the Monobe area (Arnano, 1957b).
Occurrence and geological age:-Very rare in
the medium-grained sandstone of the Bunjo Formation at Bunjo of Ochi, Sakawa area (Loc. 8);
Aptian.

Family Arcidae Lamarck, 1809
Subfamily Arcinae Lamarck, 1809
Genus Arca Linne, 1758

371

813. Cretaceous bivalves from Sakawa

Text-fig. 3. The diagramatic sketches ofArea (Eonavieula) prolata Amano, KSG 3495
(B) and KSG 3496 (A), both from the Bunjo
Formation at Bunjo of Ochi, Sakawa. (scale
5mm).
Subgenus Eonavicula Arkell, 1929
Arca (Eonavicula) prolata Amano

PI. 74, Figs. 19, 20; Text-fig. 3.
1957b. Area prolata Amano, Kumamoto Jour.
Sci., Ser. B, vol. 2, p. SO, pI. 1, figs. 13.
1965. Eonavieula prolata (Amano); Hayami,
Mem. Fae. Sci., Kyushu Uniu., Ser. D,
vol. 15, no. 2, p. 49.
1975. Area (Eonauieula) prolata Amano; Hayami, Uniu. Mus., Univ. Tokyo, Bull., no.
10, p. 32.
Materials:-KSG 3495, internal mould of rightvalve; KSG 3496, external mould of left valve;both from Bunjo of Ochi, Sakawa.
Description:-Shell small, elongately subquadrate or trapezoidal in outline, moderately inflated; umbo strongly prominent, nearly orthogyrous, located at about a fourth from front ofvalve; dorsal margin very long, nearly straight,

shorter in anterior segment than in posterior one
with about a half length of posterior; anterior
margin slightly convex, subvertically or obliquely
truncated from dorsal margin; ventral margin
long, nearly horizontal, straight in general but
sometimes sinuated in central part; posterior
margin obliquely truncated, a little convex; posterior carinal ridge indistinct but moderately
swollen; a shallow radial sulcus extends verticallyfrom umbo to ventral margin; surface ornamented by fine numerous radial ribs and laminated concentric striae; radial ribs narrower thantheir interspaces, stronger than concentric striae
on main part of surface except for reticulated
umbonal region; hinge plate very long with numerous small subvertical or diverging taxodont
teeth; ligament area very narrow with a few
chevrons; inner margin finely crenulated; both
adductor scars weakly impressed; a strong innerradial ridge extends from inner beak to about
center of inner posterior margin.
Measurements (in mm.):Specimens
KSG 3495, r. in. mol.
KSG 3496, 1. ex. mol.

Length HeightThickness

23.0
lS.4

3.0

10.2
9.S

Remarks:-This is undoubtedly conspecificwith Arca (Eonavicula) prolata Amano from the
Hagino Formation of the Monobe area (Amano,
1957b), in its strong inner radial ridge and crenulated inner ventral margin. It is discriminatedfrom Arca (Eonavicula) sp. from the Fukigoshi
Formation (Cenomanian) of the Monobe area, in
its crenulated inner ventral margin. Arca (Eonavicula) shinanoensis Yabe et Nagao (Yabe, Nagao
and Shimizu, 1926) from the Ishido Formation(Barremian) of Kwanto, is characterized by more
inflated valve, less angulated antero-dorsal comer
and smooth inner margin.
Occurrence and geological age :-Common in
the medium-grained sandstone of the Bunjo Formation at Bunjo of Ochi, Sakawa area (Loc. 8);
Aptian.
Family Cucullaeidae Stewart, 1930
Genus Cucullaea Lamarck, 1801

372

Masayuki TASHIRO and Tomoko MATSUDA

Text-fig. 4. The diagramatic sketches of
Cueullaea obliquata (Amano), KSG 3497 (B)and KSG 3498 (A), both from the Bunjo Formation at Bunjo of Ochi, Sakawa. (scale 5 mm).
Cueullaea obliquata (Amano)

PI. 74, Figs. 16-18; Text-fig. 4.
1957b. Trigonoarea (?) obliquata Amano, Kumamoto Jour. Sci., Ser. B, vol. 2, no. 2, p.
82, pI. 1, figs. 6-8.
1965. Trigonoarea sp. cf. T. obliquata Amano;
Hayami, Mem. Fae. Sci., Kyushu Univ.,
Ser. D, vol. 15, no. 2, p. 248, pI. 28, fig.
17.
1979. Trigonoarea? obliquata Amano; Matsukuma, Venus (Japan. Jour. Malae.), vol.
38, no. 2,p. 112.
Materials:-KSG 3497, internal mould of left
valve; KSG 3498, external mould of left valve;both specimens from Bunjo of Ochi, Sakawa.
Description:-Shell medium to small in size,
warped elliptical in outline, strongly tapering toanterior, longer than high, well inflated; umbo
orthogyrous, prominent but rather small, locatedat about two fifths from front of valve; dorsal
margin straight with about a half length of valve,somewhat longer in posterior than in anterior;anterior margin moderately convex, graduallychanging into very weakly arched ventral margin;
antero-dorsal corner bluntly angulated with
about 1200 ; posterior margin nearly straight or
weakly concave, obliquely trancated; posteroventral corner narrowly rounded, expanded toposterior; posteior carinal ridge distinctly angulated for Cucullaea; posterior dorsal carina narrow but distinct; posterior half of disk and posterior area (slope) ornamented by very fine numerous radial ribs; growth lines on surface weak;ligament area very narrow with a few chevron
shaped grooves; hinge plate narrow but elongated; 3 or so teeth on anterior segment of plate
elongated, nearly subhorizontal, parallel with
one another; 6 or more on posterior segment·
elongated but not so long as anterior ones, nearly
subhorizontal, parallel with one another; about
16 teeth on central part of plate very small, nearly vertical but somewhat oblique on anterior
side; inner margin smooth; posterior adductor
scar strongly impressed but anterior one very
weak; inner posterior ridge remarkably developed; fine numerous radial striae observable overshallow pallial line.
Measurements (in mm.):ThickSpecimens
Length Height ness
KSG 3497, 1. in. mol.
KSG 3498, I. ex. mol.

36.4+
24.0+

33.0
19.0+

10.0

Remarks:-KSG 3497 is a well preserved internal mould. Another specimen, KSG 3498, is imperfect external mould, but shows distinctly thecharacteristics of the surface ornamentation.
This species was referred to Trigonoarca
Conrad (1862) by Amano (1957b), Hayami(1965, 1975) and Matsukuma (1979) with somedoubts. It is, however, undoubtedly assigned togenus Cucullaea, because of its fine radial striae
on the surface and horizontally elongated teeth
on anterior and posterior segments of the hinge
plate.
Occurrence and geological age :-Rare in themedium-grained sandstone of the Bunjo Forma-813. Cretaceous bivalves from Sakawa

tion at Bunjo of Ochi, Sakawa area (Loc. 8);
Aptian. The holotype designated by Amano(1957b) is known from the Hagino Formation(Aptian) in the Monobe area, KochL

373

Subgenus Pinna Linne, 1758
Pinna (Pinna) sp. cf. P. (P.) robinaldina
d'Orbigny

PI. 75, Fig. 9.
Order Mytiloida Ferussac
Superfamily Mytilacea Rafinesque, 1815
Family Mytilidae Rafinesque, 1815
Subfamily Modiolinae Keen, 1958
Genus Modiolus Lamarck, 1799
Modiolus falcatus Amano

PI. 75, Figs. 6, 12.
1957b. Modiolus falcatus Amano, Kumamoto
Jour. Sci., Ser. B, vol. 2, no. 2, p. 91, pI.
2, figs. 3-8.
1965. Modiolus falcatus Amano; Hayami,
Mem. Fac. Sci., Kyushu Univ., Ser. D,
vol. 15, no. 2, p. 255, pI. 30, figs. 1-2.
1975.
Modiolus falcatus Amano; Hayami,
Univ. Mus., Univ. Tokyo, Bull., no. 10,
p.38.
Materials:-KSG 3499 and KSG 3501, external moulds of right valve; KSG 3500, internalmould of left valve; all from Bunjo of Ochi,
Sakawa.
Measurements (in mm.):ThickLength Height ness
Specimens

KSG 3499, r. ex. mol.
KSG 3500, 1. in. mol.

22.2
13.5

15.0
8.5

3.7

Remarks:-This species was originally established by Amano (1957b) on the material fromthe Hagino Formation of the Monobe area. Its
outline is variable from trigonal ovate to elongated elliptical.
Occurrence and geological age:-Common in
medium-grained sandstone of the Bunjo Formation at Bunjo of Ochi, Sakawa area (Loc. 8);
Aptian.

1975b. Pinna sp.; Amano, Kumamoto Jour.
Sci., Ser. B, vol. 2, no. 2, p. 85, pI. 1,
figs. 10--13.
1965. Pinna sp. cf. P. robinaldina d'Orbigny;Hayami, Mem. Fac. Sci., Kyushu Univ.,
Ser. D, vol. 15, no. 2, p. 281, pI. 39,
figs. 2-3.
1975. Pinna (Pinna) sp. cf. P. (P.) robinaldina
d'Orbigny; Hayami, Univ. Mus., Univ.
Tokyo, Bull., no. 10, p. 40.
Compare with:Pinna robinaldina d'Orbigny; Woods,
Monogr. Cretaceous Lamell. England,
vol. 1, p. 96, pI. 12, figs. 11-15, pI. 13,
fig.!.

1899.

Remarks:-Although numerous specimens of
this species are in our hands, they are all imperfect or fragmentary. This is undoubtedly conspecific with Pinna sp. which was described fromthe Hagino Formation in the Monobe area by
Amano (1957b). It is also known from the Ishido
Formation in Kwanto (Hayami, 1965) and thelower part of the Hibihara Formation in the
Monobe area (Tashiro etai., 1980).
Occurrence and geological age:-Abundant in
the medium-grained sandstone of the Bunjo Formation at Bunjo of Ochi, Sakawa area (Loc. 8);
Aptian.

Order Pterioida Newell
Suborder Pteriina Newell
Superfamily Pteriacea Gray, 1847
Family Bakevelliidae King, 1850
Genus Gervillaria Cox, 1954
Gervillaria haradae (Yokoyama)

Superfamily Pinnacea Leach, 1818

PI. 75, Figs. 1-5, 13.

Family Pinnidae Leach, 1819

1890. Avicula haradae Yokoyama, Palaeonto-

Genus Pinna Linne, 1758

graphica, vol. 36, p. 199, pI. 25, fig. 12.
haradae (Yokoyama); Yabe,

1926. Gervillia

374

Masayuki TASHIRO and Tomoko MATSUDA

Nagao and Shimizu, Sci. Rep., Tohoku
Imp. Univ., Ser. 2, vol. 9, no. 2, p. 58, pI.
13, figs. 1-3, 7, pI. 14, fig. 2.
1934. Gervillia cf. haradae (Yokoyama); Nagao,
Jour. Fac. Sci., Hokkaido Imp. Univ., Ser.
4, vol. 2, no. 3, p. 199, pI. 31, fig. 13.
1957a. Bakevellia sp.; Amano, Kumamoto Jour.
Sci., Ser. B, vol. 2, no. 2, p. 86, pI. 1, figs.
14-15.
1963. Gervillaria haradae (Yokoyama); Matsumoto, Hayami and Asano, Palaeont. Soc.
Japan, 25th Anniv. Vol., p. 32, pI. 51,
fig. 12.
1965. Gervillaria haradae (Yokoyama); Hayami,
Mem. Fac. Sci., Kyushu Univ., Ser. D,
Geol., pt. 1, vol. 15, no. 2, p. 269, pI. 35,
figs. 3-6, pI. 36, fig. 1, pI. 37, fig. 2.
1975. Gervillaria haradae (Yokoyama); Hayami,
Univ. Mus., Univ. Tokyo, Bull., no. 10, p.
46.

Materials:-KSG 3504 - KSG 3506, internalmoulds of left valve, from Bunjo of Ochi, Sakawa; KSG 3507, external mould of left valve,from the same locality; KSG 3508, internalmould of left valve, from Ujidani of Kamo,
Sakawa.
Measurements (in mm.):ThickSpecimens
Length Height ness
KSG 3504, 1. in. mol.
KSG 3505, ditto
KSG 3506, ditto
KSG 3507, I. ex. mol.

70.8
23.0+
36.5
72.8

61.5
25.8
37.0
65.0

10.5

Remarks:-This species is one of the wellknown Early Cretaceous bivalves from Japan. It
is usually found from the Monobe and Hibihara
Formations in the Monobe area. Many specimensfrom the Bunjo and Hagino Formations are in
our hands.
Occurrence and geological age:-Abundant in
the medium-grained sandstone of the Bunjo Formation at Bunjo of Ochi, Sakawa area (Loc.
8); Aptian. Rare in the medium-grained sandstone of the lower member of Tosakamo Formation (="Kaisekiyama" Formation by Katto andTashiro, 1981, non Kaisekiyama Formation by
Kurata, 1940, and Yamashita, 1961), at Ujidaniof Kamo, Sakawa area (Loc. 4); Aptian.

Genus Gervillia Defrance, 1820
Subgenus Gervillia Defrance, 1820

Gervillia (Gervillia) sp. cf. G. (G.) forbesianad'Orbigny

PI. 75, Fig. 8.
1926. Gervillia forbesiana d'Orbigny; Yabe,
Nagao and Shimizu, Sci. Rep., Tohoku
Imp. Univ., Ser. 2, vol. 9, no. 2, p. 57,
pI. 12, figs. 36-37.
1927. Gervillia forbesiana d'Orbigny; Yabe, Sci.
Rep., Tohoku Imp. Univ., Ser. 2, vol. 11,
no. 1, pI. 5, fig. 5.
1934. Gervillia forbesiana d'Orbigny; Nagao,
Jour. Fac. Sci., Hokkaido Imp. Univ., Ser.
4, vol. 2, no. 3, p. 197, pI. 24, fig. 8, pI.
25, figs. 8-10.
1951. Gervilliopsis forbesiana (d'Orbigny); Shinohara, Illustrated handbook for fossils
in Shikoku, p. 26, pI. 11, fig. 2.
1965. Gervillia (Gervillia) forbesiana d'Orbigny;Hayami, Mem. Fac. Sci., Kyushu Univ.,
Ser. D, Geol., vol. 15, no. 2, p. 276, pI.
37, figs. 7-8, pI. 38, figs. 1-5.
1972. Gervillia (Gervillia) forbesiana d'Orbigny;
Shikama and Suzuki, Sci., Rept. Yokohama Nat. Univ., Ser. 2, vol. 19, pI. 4, fig.
13.
1978. Gervillia (Gervillia) forbesiana d 'Orbigny;
Katto and Tashiro, Res. Rept., Kochi
Univ., vol. 27, p. 145, pI. 1, fig. 3.
1980. Gervillia (Gervillia) forbesiana d 'Orbigny;
Tashiro, Kozai, Okamura and Katto, Geol.
Paleont. Shimanto Belt, Taira and Tashiro
eds., Kochi, pI. 10, fig. 1.
Materials:-KSG 3508 - KSG 3509, externalmoulds; KSG 3510 - KSG 3511, internal moulds;
all from Bunjo and Yotsushiro of Ochi, Sakawa.
Remarks:-The specimens from the Bunjo
Formation are more or less imperfect, but the
specific features of Gervillia (Gervillia) forbesianad'Orbigny (see Hayami, 1965) are well shown insome of them.
Occurrence and geological age :-Common infine to medium-grained-arenite sandstone of the
Bunjo Formation at Bunjo and Yotsushiro ofOchi, Sakawa area; Aptian. Rare in mediumgrained sandstone of the lower member of Tosa-

813. Cretaceous bivalves from Sakawa

kamo Formation at Ujidani of Kamo, Sakawa
area (Loc. 4); Aptian.
Family Isognomonidae Woodring, 1925

375

Kochi, pI. 10, fig. 5.
1985. Inoceramus anglicus

Woods; Tashiro,
Matsuda and Tanaka, Mem. Fac. Sci.,
Kochi Uniu., Ser. E, Geol., vols. 5-6, p.
7, pI. 2, figs. 1-2.

Genus Isognomon Lightfoot, 1786
Isognomon sp.

PI. 75, Fig. 7.
Material:-KSG 3512, internal mould of left
valve, from Bunjo of Ochi, Sakawa.
Description:-Shell small, roundly ovate,slightly longer than high, nearly flat; ligamentarea very narrow, short with about a fifth ofvalve length, nearly straight with about 5 small
ligament pits; anterior margin well rounded;
ventral margin long, broadly arched; posterior
dorsal margin very weakly arched; posterior
margin broadly convex; postero-ventral comer
somewhat angulated; beak located at about athird from front of valve; adductor scar weakly
impressed.
Remarks:-KSG 3512, 34.1 mm long and 23.0
mm high, is a single available specimen. This issimilar to Isognomon (Melina) ichikawai Hayami(1965) from the Ishido Formation of Sanchu in
its narrow ligament area, but differs from thelatter in its elongated posterior dorsal margin.
Occurrence and geological age:-Very rare infine graind sandstone of Bunjo Formation at
Bunjo of Ochi, Sakawa area (Loc. 8); Aptian.

Family Inoceramidae Giebel, 1852
Genus Inoceramus Sowerby, 1814
Inoceramus anglicus Woods

PI. 76, Figs. 15-16, 19, 21-23.
1913. Inoceramus anglicus Woods, Monogr. Cretaceous Lamell. England, vol. 2, p. 264,
pI. 45, figs. 8-10, text-fig. 29.
1964. Inoceramus anglicus Woods; Matsumotoand Harada, Mem. Fac. Sci., Kyushu
Uniu., Ser. D, vol. 15, no. 1, p. 94, pI. 9,
figs. 1-2.
1980. Inoceramus anglicus Woods; Tashiro,
Kozai, Okamura and Katto, Geol. Paleont.
Shimanto Belt, Taira and Tashiro eds.

Materials:-KSG 3513 - KSG 3514, internaland external moulds of right valve from Kurohara of Ochi, Sakawa; KSG 3516 and KSG 3515,
conjoined valves from the same locality.
Measurements (in mm.):ThickSpecimens
Length Height ness

KSG 3513, r. valve
KSG 3514, ditto
KSG 3515, conj. valve
KSG 3516, ditto

21.1
9.0
12.5

18.0
12.0
26.5
14.5

2.0
0.9
1.3

Remarks:-The specimens from this area arecertainly identical with Inoceramus anglicus
Woods, 1913 from the Albian of England in
all the external and internal characters whichwere described by Woods (1913). Specimen of
KSG 3513 resembles more especially a specimen of 1. anglicus by Woods (pI. 45, fig. 9) in
its features of outline and arrangement of ribbing.
Occurrence and geological age :-Rare in darkgray siltstone of the Yotsushiro Formation at
Kurohara of Ochi, Sakawa area (Loc. 3); Upper
Albian?
Inoceramus sp. aff.1. crippsi Mantell

PI. 76, Figs. 17-18.
Compare with:crippsi Mantell; Woods,
Monogr. Cretaceous Lame II. England,
vol. 2, p. 273, pI. 48, figs. 2-3.

1913. Inoceramus

Materials:-KSG 3517, internal and externalmoulds of right valve, from Kurohara of Ochi,
Sakawa.
Description:-Shell small, roundly ovate,higher than long; umbo slightly prominent,
located at about one eighth from front of valve;
hinge line straight with about a half length ofvalve; anterior margin nearly straight for about ahalf of height; ventral margin broadly arched in376

Masayuki TASHIRO and Tomoko MATSUDA

anterior part but well rounded in posterior half;
posterior margin nearly straight obliquely truncated; surface ornamented with irregularly
spaced concentric wrinkles; umbonal angle about
100°.
Remarks:-KSG 3517 is measured 17.2 mm inlength, 19.7 mm in height and 1.7 mmin thickness. The concentric wrinkles of the surface are
10 or more in number, distinct near the anterior
marginal and on the anterior ventral parts but
nearly obsolete on the posterior marginal part.
The described specimen resembles the immatureform of Inoceramus crippsi Mantell by Woods(1913, see p. 277, text-fig. 35) from the Albianof England, in its features of hinge line and postero-ventral expansion of the valve.
Occurrence and geological age:-Rare in darkgray siltstone of the Yotsushiro Formation at
Kurohara of Ochi, Sakawa area (Loc. 3); Albian.
Inoceramus sp.

PI. 76, Figs. 20, 24.
Materials:-KSG 3518 and KSG 3519, imperfect right valves, from Kurohara of Ochi, Sakawa.
Remarks:-Two fragmental specimens arecharacterized by numerous concentric ribs andrings. Although the outline of the species is imperfectly shown, this is probably referable toInoceramus, judging from its concentric ornamentation.
Occurrence and geological age:-Very rare in
dark-gray siltstone of the Yotsushiro Formation
at Kurohara of Ochi, Sakawa (Loc. 3); Albian.

1965.

1973.

1975.

1977.

Renevier); Amano, Kumamoto Jour.
Sci., Ser. B, vol. 2, no. 2, p. 88, pI. 1,
figs. 17-18, 20-25, 27-29.
Neithea (Neithea) amanoi Hayami,
Mem. Fac. Sci., Kyushu Univ., Ser. D,
Geol., vol. 15, no. 2, p. 229, text-fig. 4,
pI. 41, figs. 8-10, pI. 42, figs. 1-4.
Neithea (Neithea) syriaca (Conrad);Dhondt, Mem. Inst. Roy. Sci. Nat.
Belgique, no. 176, p. 37.
Neithea (Neithea) syriaca (Conrad);Hayami, Univ. Mus., Univ. Tokyo, Bull.,no. 10, p. 75.
Neithea (Neithea) syriaca amanoi Hayami; Hayami and Noda, Trans. Proc.,
Palaeont. Soc. Japan, N.S., no. 105, p.
49.

Materials:-KSG 3520 - KSG 3521, external
and internal moulds, from Bunjo of Ochi, Sakawa; KSG 3522 - KSG 3523, internal and external moulds, from Yotsushiro of Ochi, Sakawa.
Measurements (in mm.):ThickLength Height ness
Specimens

KSG 3520, r. ex. mol.
KSG 3521, 1. in. mol.
KSG 3522, r. ex. mol.

17.1
19.0
11.8

22.6
24.9
15.3

6.3
3.8

Remarks:-Numerous specimens are obtained
from the Sakawa area. They are safely referable
to Neithea (Neithea) syriaca amanoi Hayami(1965) from the Hagino Formation in the Monobe area, Shikoku, by their characteristic featuresof the valve.
Occurrence and geological age:-Abundant infine-grained sandstone of the Bunjo Formation
at Bunjo and Yotsushiro, both of Ochi, Sakawa
area (Locs. 8, 9); Aptian.

Superfamily Pectinacea Rafinesque, 1815
Family Pectinidae Rafinesque, 1815

Family Propeamussiidae Abbott, 1954

Subfamily Pectininae Rafinesque, 1815

Genus Parvamussium Sacco, 1897

Genus Neithea Drouet, 1825

Parvamussium hinagense Tamura

Subgenus Neithea Drouet, 1825

PI. 76, Figs. 7-9, 13.

Neithea (Neithea) syriaca amanoi Hayami

1973. Parvamussium hinagense Tamura, Geol.
Pal. Southeast Asia, vol. 11, p. 122, pI.
17, figs. 1-4.
1975. Parvamussium hinagense Tamura; Haya-

PI. 74, Figs. 21-22.
1957b. Pecten (Neithea) cf. morrisi (Pictet et813. Cretaceous bivalves from Sakawa

mi, Univ. Mus., Univ. Tokyo, Bull., no.
10, p. 83.

Materials:-KSG 3523, internal mould of rightvalve, from Kuroishi, north of Kamo, Sakawa;
KSG 3524 and KSG 3525, external moulds ofright and left valves from Kuroishi.
Measurements (in mm.):-Specimens
KSG 3523, r. in. mol.
KSG 3524, r. ex. mol.
KSG 3525, 1. ex. mol.

Length Height
12.8
8.4
18.2

16.0
8.5+

Remarks:-The species based on three specimens from Sakawa area, is undoubtedly conspecific with Paroamussium hinagense Tamura(1973) from the Hinagu Formation of Yatsushiro in central Kyushu, in its strong radial ridgesof the inner surface and the fine radial riblets
which cross the distinct concentric ribs on theright external surface.
Occurrence:-Rare in dark-gray siltstone of
the upper member of Tosakamo Formation at
Kuroishi, about 700 m north of Kamo, Sakawa
area (Loc. 6); Albian.
Paroamussium tosaense, sp. nov.

PI. 76, Figs. 3, 5-6, 11-12.
1980. Parvamussium sp.; Tashiro, Kozai, Okamura and Katto, Geol. Paleont. Shimanto
Belt, Taira and Tashiro eds., Kochi, pI.
10, fig. 3.

Materials:-KSG 3526 and KSG 3528, internalmoulds of right and left valves; KSG 3529, external mould of left valve; these three form Yotsushiro of Ochi, Sakawa; KSG 3527, internalmould of right valve, from Kurohara of Ochi,
Sakawa; KSG 3530, external mould of right valve,from Kuroishi of Kamo, Sakawa.
Diagnosis:-Shell roundly ovate, strongly inequivalve; inner radial ridges about 10 in number;surface of left valve with numerous primary andsecondary ribs; right valve with abundant concentric riblets.
Description:-Shell medium to small in size,
roundly ovate, slightly taller than length in general, slightly inflated; umbo less prominent,

377

located at center of valve; umbonal angle about
90°; both ears moderate in size, with anterior
one somewhat larger than posterior; surface ofright valve ornamented with numerous fine concentric ribs narrower than interspaces; surface ofleft valve with fine radial ribs composed of about
30 primary and about 30 secondary ones in alternation; inner surface with about 10 weak innerradial ridges several of which do not reach theumbonal axis; the inner ridges of left valve notreach the periphery of ventral margin; resili~ervery small under beak; a pair of cardinal crurae
developed on both sides of resilifer.
Measurements (in mm.):Specimens
KSG 3526, holotype, I. in. mol.
KS.G 3527, paratype, ditto
KSG 3528, ditto, I. in. mol.
KSG 3529, ditto, I. ex. mol.
KSG 3530, ditto, r. ex. mol.

Length Height
8.0
8.9
6.2
12.3
8.4

7.9
9.8
6.4
8.3

Remarks:-This is clearly discriminated from
Paroamussium kimurai (Hayami, 1965), from theBarremian of southwest Japan, in its weakerradial ribs of the left valve. It is similar to Paroamussium yubarense (Yabe et Nagao) from theUpper Cretaceous strata (Cenomanian to Lower
Campanian) of Japan (Tashiro, 1976; 1985), in
its outline and radial ribs of the left valve, but isdistinguishable from the latter in its more numerous concentric ribs of the right valve and imperfect inner radial ridges. Paroamussium sp. by
Tashiro et al. (1980) from the upper member ofthe Hibihara Formation in the Monobe area, issafely referable to this species, judging fromsame diagnostic features. Several specimens collected from the Tomochi Formation in central
Kyushu are also probably conspecific with thisspecies.
Occurrence and geological age :-Common in
dark-gray siltstone of the upper member of Tosakamo Formation at Kuroishi, about 700 m northof Kamo, Sakawa area (Loc. 6); Albian? Common in dark-gray siltstone of the Yotsushiro
Formation at Yotsushiro of Ochi, Sakawa area
(Loc. 7); Albian.

Masayuki TASHIRO and Tomoko MATSUDA

378

Parvamussium kattoi, sp. nov.

PI. 76, Figs. 1-2, 10.
1985. Parvamussium sp.; Tashiro, Matsuda andTanaka, Mem. Fac. Sci., Kochi Univ., Ser.
E, Geol., vols. 5-6, p. 8, pI. 1, figs. 26,
27.

Materials:-KSG 3531, holotype, externalmould of left valve; KSG 3532, paratype, internal mould of right valve; KSG 3533, paratype, external mould of left valve; all from Kurohara ofOchi, Sakawa.
Description:-Shell small, roundly ovate, vertically elongated, with moderately inflated inleft and slightly swollen in right valves; umbo
nearly central; apical angle about 85°; surface ofleft valve ornamented with numerous fine concentric ribs; surface of left valve with primary andsecondary radial ribs; primary ones number
about 20, round-topped; secondary ones very
weak, about 20 in number; inner radial ridges
distinct, number 8 or 9; both ears moderate insize.
Measurements (in mm.):ThickSpecimens
Length Height ness

KSG 3531, holotype,I. ex. mol.
KSG 3532, paratype,r. in. mol.
KSG 3533, ditto,r. ex. mol.

6.9

10.1

6.3

9.8

5.3

7.3

0.5

1.3

Observation:-This species is specially characterized by the inflated left valve and oblong
outline for Parvamussium. Narrow and shortsecondary radial ribs of left valve generally
appear on the ventral part. The concentric ribsof right valve are narrower than their interspaces.
Comparison:-This species is undoubtedly
conspecific with Parvamussium sp. which had
been described in detail based on the specimensfrom the Albian stratum in Oita, Kyushu by
Tashiro and Matsuda (in Tashiro, Matsuda andTanaka, 1985), judging from the same diagnostic
features.
This species is discriminated from Parvamussium tosaense from the same formation by its

inflated valve and distinct radial ribs. The hitherto described species of Parvamussium from theCretaceous of Japan, i.e., Parvamussium kimurai(Hayami), P. yubarense (Yabe et Nagao) and P.
hinagense Tamura, are easily discriminated fromthis species in their less inflated left valve andmore rounded valve.
Occurrence and geological age:-Very rare in
dark-gray siltstone of the Yotsushiro Formation
at Kurohara of Ochi, Sakawa area (Loc. 2);
Albian.
Family Plicatulidae Watson, 1930
Genus Plicatula Lamarck, 1801
Plicatula sp.

PI. 76, Fig. 14.
Material:-KSG 3534, internal mould of left
valve, from Bunjo of Ochi, Sakawa.
Remarks:-A single specimen, KSG 3534,
11.2 mm long and 13.9 mm high, shows clearly
the inner features of left valve but indistinctly
other features. The shell is subtriangular in outline, higher than long. The umbo is located nearly central. Seven inner radial ridges corresponding to the external radial ribs are observable distinctly. The ligament area. is narrowly triangular.
This species is probably conspecific with thespecimens from the middle member of the Doganaro Formation of the Shimanto Belt in Shikoku(Tashiro et al., 1981, not described but listed), in
the same features of the inner surface.
Occurrence and geological age:-Rare in finegrained sandstone of the Bunjo Formation at
Bunjo of Ochi, Sakawa area (Loc. 8); Aptian ..

Subclass Palaeoheterodonta Newell
Order Trigonioida Dall
Superfamily Trigoniacea Lamarck, 1819
Family Trigoniidae Lamarck, 1819
Subfamily Trigoniinae Lamarck, 1819
Genus Nipponitrigonia Cox, 1952
Nipponitrigonia kikuchiana (Yokoyama)
1891. Trigonia

kikuchiana Yokoyama, Jour.

813. Cretaceous bivalves from Sakawa
Coli. Sci., Imp. Univ. Tokyo, Sec. 2, vol.
4, art. 2, p. 363, pI. 40, figs. 4-6.
1957. Nipponitrigonia
convexa
Kobayashi,Trans. Proc., Palaeont. Soc. Japan, N.S.,
no. 26, p. 55, pI. 10, fig. 14, pI. 11, figs.
4-7.
1975. Nipponitrigonia
convexa
Kobayashi;
Hayami, Univ. Mus., Univ. Tokyo, Bull.,no. 10, p. 106.
1980. Nipponitrigonia
convexa
Kobayashi;

Tashiro, Kozai, Okamura and Katto,
Geol. Paleont. Shimanto Belt, Taira andTashiro eds., Kochi, pI. 10, fig. 13.
Material:-KSG 3435, moulds included in aboulder of sandstone, from Kurohara of Ochi,
Sakawa.
Remarks:-This species is characterized bywell inflated valve, more or less small in size andstrong 4 or more concentric costae near theumbo. The outline of the valve is very variable:
subtrigonal, elongated ovate, subquadrate or
elliptical. It is discriminated from "Nipponitrigonia kikuchiana (Yokoyama)", from the
Miyako Group in northeast Japan (Yehara, 1915,
1923) and from the Goshonoura Group in central Kyushu (Yehara, 1923), in its strong concentric costae near the umbo and inflated valve. It
should be noted that the specimens in our collection from the Hanoura Formation in Katsuura,
Tokushima Prefecture, the probable type localityof Trigonia kikuchiana Yokoyama, 1891, also
show well inflated valves, subtrigonal outline andstrong concentric costae near the umbo, and areprobably conspecific with the present species.
Therefore, a taxonomic new name is necessary
for the specimens from the Miyako and Goshonoura Groups by Yehara (1915, 1923). This
species is also known from the lower part of Hoji
Formation in Tokushima, the lower part of Hibihara Formation in Kochi, the Aptian strata of
Osaka in Oita, and the lower part of Hinagu Formation in Kumamoto (Tashiro, 1985).
Occurrence and geological age:-Abundant inmedium-grained sandstone of the Kurohara Formation at Kurohara (Sendatsuno by Kobayashi,1957) of Ochi, Sakawa area (Loc. 1); Aptian.

379

Subfamily Pterotrigoniinae van Hoepen, 1929
Genus Pterotrigonia van Hoepen, 1929
Subgenus Pterotrigonia van Hoepen, 1929
Pterotrigonia (Pterotrigonia) pocilliformis(Yokoyama)

PI. 74, Figs. 24-27.
Synonymy:-(See Tashiro and Matsuda, 1983,p.18).
Materials:-KSG 3436, external mould of left
valve, from Kurohara of Ochi, Sakawa; KSG
3437 - KSG 3438, external moulds of rightvalve; KSG 3439, internal mould of right valve,latter three from Ujidani of Kamo, Sakawa.
Measurements (in mm.):-Specimens
KSG 3436, I. ex. mol.
KSG 3437, r. ex. mol.
KSG 3438, r. ex. mol.
KSG 3439, r. in. mol.

Length Height
36.9+
16.0
33.7

21.0
32.0
9.8
22.0

Thickness
8.0
9.8
3.0

Remarks:-The specimens from the Kurohara
Formation are certainly referable to Pterotrigonia (Pterotrigonia) pocilliformis (Yokoyama), as
already redescribed by Yehara (1923), and Kobayashi and Nakano (1957). The specimens fromthe Tosakamo Formation are also undoubtedly
conspecific with P. (P.) pocilliformis in its elongated outline, arrangements of the ribs on area,
disk and escutcheon. Recently, Tashiro andMatsuda (1983) classified P. (P.) pocilliformis
into two forms, i.e., A Form (with parallel
costae) and B Form (with radial costae) by theminor difference in the arrangements of thecostae on the disk. The present specimens fromthe Sakawa area are identical with B Form ofP. (P.) pocilliformis.
Occurrence and geological age:-Abundant inmedium-grained sandstone of the Kurohara Formation at Kurohara (Sendatsuno) of Ochi, Sakawa area (Loc. 1); Aptian. Common in fine- tomedium-grained sandstone of the lower memberof Tosakamo Formation at Ujidani of Kamo,
Sakawa area (Loc. 4); Aptian.

380

Masayuki TASHIRO and Tomoko MATSUDA

Subgenus Scabrotrigonia Dietrich, 1933
Pterotrigonia (?Scabrotrigonia) moriana (Yehara)

PI. 74, Fig. 23.
Synonymy, material, description and measurements:-See Tashiro and Matsuda, 1983, p. 23.
Remarks:-Numerous specimens in internaland external moulds are in our hands. They aresafely referable to Pterotrigonia (?Scabrotrigonia) moriana (Yehara) from the Hagino Forma·tion of the Monobe area (Yehara, 1927) judging
from the diagnostic features of costae and cos·tellae on the surface.
Occurrence and geological age:-Abundant infine- to medium·grained sandstone of the Bunjo
Formation at Bunjo and Yotsushiro of Ochi,
Sakawa area (Locs. 8, 9); Aptian.
Pterotrigonia (?Scabrotrigonia) sp.
Material, description and remarks:-See Tashi·
ro and Matsuda, 1983.
Occurrence and geological age:-Abundant infine-grained sandstone of the Bunjo Formation at
Bunjo of Ochi, Sakawa area (Loc. 8); Aptian.

Subclass Heterodonta Neumayr

terior margin moderately convex, subtruncatedfrom long and weakly arched, posterior dorsal
margin; surface ornamented with numerous
concentric ribs which are narrower than theinterspaces; umbonal angle about 1200 ; lunulevery narrow; escutcheon indistinct.
Measurements (in mm.):ThickLength Height ness
Specimens
KSG 3440, I. ex. mol.
KSG 3441, ditto

13.0
7.0

11.8
6.1

2.0
1.2

Observation :-The inner features and hinge
structure are unknown. The concentric ribs are
crowded near the umbonal part but widely
spaced later. The number of ribs is about 20 in
KSG 3440.
Comparison:-This species is similar to Lucinoma? kotoi (Nagao) from the Miyako Group in
northeast Japan (Hayami, 1965) in its rounded
outline, but differs in its smaller size and has
more numerous ribs. Since the hinge structure ofthis species is not observable, its generic positionis uncertain.
Occurrence and geological age :-Rare in fineto medium-grained sandstone of the lower member of Tosakamo Formation at Ujidani of Kamo,
Sakawa area (Loc. 4); Aptian.

Order Veneroida Adams et Adams
Superfamily Lucinacea Fleming, 1828

Superfamily Carditacea Fleming, 1828

Family Lucinidae Fleming, 1828

Family Carditidae Fleming, 1828

Subfamily Myrteinae Chavan, 1969

Genus Xenocardita Vokes, 1946

Genus Lucinoma Dall, 1901

Xenocardita amanoi (Hayami)

Lucinoma? sp.

PI. 75, Figs. 10-11.

PI. 77, Figs. 15-16.

1957b. Cardita (?) sp.; Amano, Kumamoto
Jour. Sci., Ser. B, vol. 2, no. 2, p. 38,
pI. 2, figs. 27-29, text-fig. 2.
1965. Pseudocardia amanoi Hayami, Mem.
Fac. Sci., Kyushu Univ., Ser. D, vol.
17, no. 2, p. 79, pI. 7, figs. 4-7.
1975. Xenocardita amanoi (Hayami); Hayami,
Univ. Mus., Univ. Tokyo, Bull., no. 10,
p.124.

Materials:-KSG 3440 and KSG 3441, external moulds of left valves, from Ujidani of Kamo,
Sakawa.
Description:-Shell small, subovate, slightly
longer than high, weakly inflated; umbo small,prosogyrous, a little prominent, located at abouta third from front of valve; anterior dorsal
margin short, weakly concave; anterior margin
slightly arched, subtruncated from anterior
dorsal margin; ventral margin subcircular; pos-Materials:-KSG 3442 - KSG 3445, externalmoulds of left and right valves, from Bunjo of
Ochi, Sakawa; KSG 3446, external mould of

813. Cretaceous bivalves from Sakawa

left valve, from Yotsushiro of Ochi, Sakawa.
Measurements (in mm.):ThickSpecimens
Length Height ness
KSG 3442, 1. ex. mol.
KSG 3446, I. ex. mol.

6.2
5.5

6.5
7.0

2.1
1.8

Remarks:-The specimens from the Sakawa
area are safely identical with Xenocardita amanoi(Hayami) from the Hagino Formation in the
Monobe area, in the diagnostic features whichwere described clearly by Hayami (1965).
Occurrence and geological age:-Common in
fine- to medium-grained sandstone of the Bunjo
Formation at Bunjo and Yotsushiro of Ochi,
Sakawa area (Locs .. 8, 9); Aptian.

Superfamily Crassatellacea Ferussac, 1822
Family Astartidae d'Orbigny, 1844
Subfamily Astartinae d'Orbigny, 1844
Genus Astarte Sowerby, 1816
Subgenus Astarte Sowerby, 1816
Astarte (Astarte) subsenecta Yabe et Nagao

PI. 75, Fig. 14; PI. 77, Figs. 17-19, 25-26.
1926. Astarte subsenecta Yabe et Nagao, in

Yabe, Nagao and Shimizu, Sci. Rep.,
Tohoku Imp. Uniu., Ser. 2, vol. 9, no. 2,
p. 47, pI. 13, figs. 14-16, pI. 14, fig. 11.
1965. Astarte (Astarte) subsenecta Yabe et
Nagao; Hayami, Mem. Fac. Sci., Kyushu
Uniu., Ser. D, Geol., vol. 17, no. 2, p. 81,
pI. 7, figs. 10-18, pI. 14, figs. 1-5.
1972. Astarte (Astarte) subsenecta Yabe et
Nagao; Shikama and Suzuki, Sci. Rept.,
Yokohama Nat. Uniu., Ser. 2, vol. 19, pI.
6, fig. 4.
1975. Astarte (Astarte) subsenecta Yabe et
Nagao; Hayami, Uniu. Mus., Uniu. Tokyo,
Bull., no. 10, p. 125.
1980. Astarte (Astarte) subsenecta Yabe et
Nagao; Hayami, in Hayami and Oji,Trans. Proc., Palaeont. Soc. Japan, N.S.,
no. 105, p. 431, pI. 53, figs. 1-6.
1980. Astarte (Astarte) subsenecta Yabe et
Nagao; Tashiro, Kozai, Okamura andKatto, Geol. Paleont. Shimanto Belt,
Taira and Tashiro eds., Kochi, p. 75.

381(Astarte) subsenecta Yabe et
Nagao; Tashiro and Matsuda in Tashiro,
Matsuda and Tanaka, Mem. Fac. Sci.,
Kochi Uniu., Ser. E, vols. 5-6, p. 10, pI.
2, fig. 16, pI. 3, figs. 1-3.

1985. Astarte

Materials:-KSG 3476, internal mould of rightvalve; KSG 3475, external mould of left valve;both from north of Hirooka, Kamo, Sakawa;
KSG 3472 and KSG 3473, internal moulds ofright valve, from Ujidani of Kamo, Sakawa; KSG
3477 and KSG 3474, external moulds of rightvalve, from Ujidani of Kamo, Sakawa.
Measurements (in mm.):ThickSpecimens
Length Height ness

KSG 3472, r. in. mol.
KSG 3473, ditto
KSG 3476, ditto
KSG 3474, r. ex. mol.

19.8
14.2
18.5
14.9

18.9
15.0
20.0
13.9

2.0

Remarks:-Although the present specimensfrom this area are not well preserved, they are
undoubtedly conspecific with Astarte (Astarte)
subsenecta Yabe et Nagao, a well known species
from the Lower Cretaceous in Japan, in theirfeatures of valve, hinge structure and surface
ornamentation.
Occurrence and geological age:-Rare in finegrained sandstone of the lower member of Tosakamo Formation at about 900 m north of Hirooka of Kamo, Sakawa area (Loc. 5); Aptian. Rarein fine- to medium-grained sandstone of the sameformation at Ujidani of Kamo, Sakawa area (Loc.
4); Aptian.

Subgenus Trautscholdia Cox et Arkell, 1948
Astarte sp. cf. Astarte (Trautscholdia) minor
Nagao

PI. 77, Figs. 20-24.
Compare with:1934. Astarte minor Nagao, Jour. Fac. Sci.,
Hokkaido Imp. Uniu., Ser. 4, vol. 2, no.

3, p. 220, pI. 28, figs. 5-10.
1965. Astarte (Nicaniella) minor Nagao; Haya-mi, Mem. Fac. Sci., Kyushu Uniu., Ser. D,
Geol., vol. 17, no. 2, p. 91, pI. 8, figs.
19-22.

Masayuki TASHIRO and Tomoko MATSUDA

382

1975. Astarte (Trautscholdia) minor Nagao;
Hayami, Univ. Mus., Univ. Tokyo, Bull.,no. 10, p. 126.

Materials:-KSG 3466 and KSG 3468, internalmoulds of left and right valves, from Ujidani ofKamo, Sakawa; KSG 3469 - KSG 3471, externalmoulds of left and right valves, from the same
locality.
Measurements (in mm.):ThickLength Height ness

Specimens
KSG 3469, r. ex. mol.
KSG 3471, 1. ex. mol.
KSG 3466, 1. in. mol.
KSG 3467, r. in. mol.
KSG 3468, 1. in. mol.

8.3
9.0
8.6
7.7
7.9

6.1
7.1
5.8
6.9
6.4

0.7
0.8

Remarks:-This species is closely similar to
Astarte (Trautscholdia) minor Nagao from the
Miyako Group of northeast Japan (Nagao, 1934;
Hayami, 1965), in its small valve, distinct concentric costae on the surface and chestnut-like
outline of the valve, but slightly differs in its
more numerous concentric costae.
Occurrence and geological age:-Common in
fine- to medium-grained sandstone of the lower
member of Tosakamo Formation at Ujidani ofKamo, Sakawa area (Loc. 4); Aptian.

Superfamily Cardiacea Lamarck, 1809
Family Cardiidae Lamarck, 1809
Subfamily Protocardiinae Keen, 1951
Genus Protocardia von Beyrich,.1845
Subgenus Protocardia von Beyrich, 1845
Protocardia (Protocardia) amanoi, sp. nov.

PI. 77, Figs. 10-14; Text-fig. 5.
1957b. Protocardium sp.; Amano, Kumamoto
Jour. Sci., Ser. B, vol. 2, no. 2, p. 100,
pI. 2, figs. 31-34.

Materials:-The holotype, KSG 3448, external mould of right valve, from Bunjo of Ochi,
Sakawa; paratypes, KSG 3449 - KSG 3451, external moulds of left and right valves from thesame locality as the holotype.
Diagnosis:-Shell roundly subquadrate in outline; umbo prominent but small; disk smooth;posterior area with several distinct radial ribs;
inner margin not crenulated.
Description:-Shell small, roundly subquadrate, nearly equivalve, somewhat inequilateral,higher than long in general, moderately inflated;umbo orthogyrous, weakly prominent for Proto-

Superfamily Solenacea Lamarck, 1809
Family Cultellidae Davies, 1935
Genus Leptosolen Conrad, 1865
Leptosolen sp.
Material:-KSG 3447, internal mould of rightvalve, from Ujidani of Kamo, Sakawa.
Remarks:-KSG 3447 is an imperfect specimen, measured about 20 mm in length and 6 mm
in height. A vertical inner buttress is distinctly
observable under the beak which is located atabout a fourth from front of valve. Several
other fragmental specimens are still more imperfectly preserved.
Occurrence and geological age:-Very rare infine-grained sandstone of the lower member of
Tosakamo Formation at Ujidani of Kamo, Sakawa area (Loc. 4); Aptian.

Text-fig. 5. The diagramatic
sketch of Protocardia (Protocardia)
amanoi Tashiro etMatsuda, sp. nov.,
holotype from the Bunjo Formation at Bunjo of Ochi, Sakawa.
(scale 5 mm).

813. Cretaceous bivalves from Sakawa
cardia, pointed, nearly central or slightly anteriorly placed; anterior dorsal margin short, weakly
concave; posterior dorsal margin nearly straight,
somewhat shouldered; anterior margin subvertically truncated, nearly straight or weakly convex; ventral margin moderately arched; posterior
margin obliquely truncated, nearly straight; postero-ventral margin narrowly rounded; posteriorcarinal ridge indistinct but observable as a boundary line between smooth disk and ribbed posterior slope; radial ribs on posterior slope (area)
round-topped, about 10, broader than theirinterspaces; hinge plate narrow but elongatedwith small cardinal teeth and long but narrow
lateral teeth; inner margin smooth; growth lines
on surface indistinct.
Measurements (in mm.):ThickSpecimens
Length Height ness

KSG 3448, holotype,r. ex. mol.
KSG 3449, paratype,I. ex. mol.
KSG 3450, ditto,
ditto

19.0+

20.0

4.9

11.0

11.2

2.8

12.5

11.5+

2.5

Observation:-This species is variable in theoutline as already mentioned by Amano (1957b).
The radial ribs on the posterior slope are constantly 10 in number. The specimens from thisarea are more or less incomplete, but they show
well the diagnostic characters.
Comparison:-This species is easily discriminated from Portocardia hiraigensis Hayami(1965) from the Miyako Group of northeast
Japan, in its distinct radial ribs on the posterior
slope. It is characterized by smaller size and more
distinct and less numerous radial ribs on theposterior slope than Protocardia koshikijimensis
Amano (1957a) (Tashiro, 1976) from the Himenoura Group in Kyushu. It resembles Pro tocardia beiha Vokes (1946) from the Aptian of
Lebanon in the arrangements of the radial ribs,
but differs in its more numerous radial ribs andsubquadrate outline.
Occurrence and geological age:-Rare in fineto medium-grained sandstone of the Bunjo Formation at Bunjo and Yotsushiro of Ochi, Sakawa

383

area (Locs. 8,9); Aptian.
Subfamily Laevicardiinae Keen, 1936
Genus Laevicardium Swainson, 1840
Laevicardium? ishidoense (Yabe et Nagao)

PI. 77, Figs. 8-9.
1926. Cardium ishidoensis Yabe et Nagao, in

Yabe, Nagao and Shimizu, Sci. Rep.,
Tohoku Imp. Univ., Ser. 2, vol. 9, no. 3,
p. 48, pI. 12, figs. 9,16,18.
1965. Laevicardium (?) ishidoensis (Yabe et
Nagao); Hayami, Mem. Fac. Sci., Kyushu
Univ., Ser. D, vol. 17, no. 2, p. 123, pI.
17, figs. 8-10.
1975. Laevicardium? ishidoensis (Yabe et Nagao); Hayami, Univ. Mus., Univ. Tokyo,
Bull., no. 10, p. 134.
1978. Laevicardium? ishidoensis (Yabe et Nagao); Katto and Tashiro, Res. Rep., Kochi
Univ., vol. 27, p. 146, pI. 1, figs. 12-15.
1980. Laevicardium (?) sp. aff. L. (?) ishidoense; Hayami in Hayami and Oji, Trans.
Proc., Palaeont. Soc. Japan, N.S., no.
120, p. 434, pI. 53, fig. 7.
Materials:-KSG 3452 and KSG 3453, external moulds of left valve, from the northeast of
Ujidani, Kamo, Sakawa.
Remarks:-KSG 3452, 32.8 mm high and 8.0mm thick, is weathered on the posterior marginal
part. Another specimen, KSG 3453, is a fragmentary left valve. Although they are imperfect,
the characteristic surface ornamentation andoutline of the valve are well preserved. They are
undoubtedly conspecific with Laevicardium?
ishidoense (Yabe et Nagao), from the Ishido Formation in Sanchu (Yabe, Nagao .and Shimizu,
1926; Hayami, 1965), in its vertically elongatedoutline and very fine delicate radial ribs.
Occurrence and geological age:-Very rare in
medium-grained sandstone of the lower memberof Tosakamo Formation at about 800 m north of
Hirooka (northeast of Kamo), Kamo Sakawa area
(Loc. 5); Aptian.
Laevicardium? corpulentum (Amano)

PI. 77, Figs. 1-7.

Masayuki TASHIRO and Tomoko MATSUDA

384

in Monobe area, type locality by Amano (1957b).
This species clearly differs from Laevicardium?
ishidoense (Yabe et Nagao) in its more prominent umbo, more vertically elongated outline andfar more delicate radial ribs on the surface thanthose of the latter.
Occurrence and geological age :-Common in
fine- to medium-grained arenite sandstone of the
Bunjo Formation at Bunjo of Ochi, Sakawa area
(Loc. 8); Aptian.

1957b. Cardium corpulentum Amano, Kuma·
moto Jour. Sci., Ser. B, vol. 2, no. 2, p.
99, pI. 2, fig. 30.
1965. Laeuicardium (?) corpulentum (Amano);Hayami, Mem. Fac. Sci. Kyushu Uniu.,
Ser. D, vol. 17, no. 2, p. 125, pI. 15, fig.
11.
1975. Laeuicardium? corpulentum (Amano);Hayami, Uniu. Mus., Uniu. Tokyo, Bull.,no. 10, p. 135.
Materials:-KSG 3454, external mould of left
valve; KSG 3455 and KSG 3456, internal moulds
of left and right valves; KSG 3457, externalmould of left? valve; all from Bunjo of Ochi,
Sakawa.
Measurements (in mm.):Thick·Specimens
Length Height ness

KSG 3454, I. ex. mol.
KSG 3455, r. in. mol.
KSG 3456, I. in. mol.

21.6
20.3
24.2

26.9
25.0
28.1

Superfamily Myacea Lamarck, 1809
Family Corbulidae Lamarck, 1818
Subfamily Caestocorbulinae Vokes, 1945
Genus Caestocurbula Vincent, 1910
Caestocorbula minima Hayami

PI. 77, Figs. 27-30.

11.5

1980. Caestocorbula minima Hayami, in Hayami and Oji, Trans. Proc., Palaeont. Soc.
Japan, N.S., no. 120, p. 437, pI. 53, figs.
15,16.

Remarks:-The specimens from the Bunjo
Formation are in favorable preservation morethan the specimens from the Hagino Formation
AGES~

SAKAWA------X3 - - - -ALBIAN

YOTSUSHIR62.7
F--- -- ----- --XI

u..
0 X6
:E

0
KUROHARA F-:E

1--------:E

c:

u..

w

Il.
Il.
:::l

--- ---?----

« X4
:.::
:E
« Xs c:en

APTIANI-MONOBE

AREA

w

~

BUNJO

F XB.9HAUTERIVIAN

F

w

Il.
Il.
:::l

.- --- ----1---

«
c:
«

:E

-------------IDc:

KAISEKIYAMA F

J:

w

~

HAGINOF

FUNADANIF

IGENOKIF

0..JYUNOKIBARREMIAN

FlJKIGOSH/- - - -? - - - -c:

J:

9 -------

AREA

F---?---MONO BEF

RYOSEKIF

Text-fig. 6. The correlational diagram of the Lower Cretaceous strata of the Sakawa and Monobe
areas in Kochi. X: fossil localities.

813. Cretaceous bivalves from Sakawa
Materials:-KSG 3458 - KSG 3460, internalmoulds of right valve; KSG 3461 - KSG 3463,
internal moulds of left valve; all from Ujidani ofKamo, Sakawa.
Measurements (in mm.):-Spcimens

385

terior area.
Occurrence and geological age :-Rare in finegrained sandstone of the lower member of Tosakamo Formation at Ujidani of Kamo, Sakawa
area (Loc. 4); Aptian.

Length HeightKSG 3458, r. iIi. mol.
KSG 3459, ditto
KSG 3461, I. in. mol.
KSG 3463, ditto

7.5
9,0
7.5
8.3

Concluding remarks

5.3
7.5
5.0
6.2

Remarks:-Numerous specimens are in ourhands. They are undoubtedly conspecific with
Caestocorbula minima Hayami (Hayami and Oji,
1980) from the Aptian Choshi Group in central
Japan on account of its diagnostic features
which were well defined by Hayami (in Hayami
and Oji, 1980). This species also occurs abundantly from the Aptian Hibihara (=Kaminiro)
Formation in the Monobe area, Shikoku, as reported by Tashiro et al. (1980).
Occurrence and geological age:-Abundant infine- to medium-grained sandstone of the lower
member of Tosakamo Formation at Ujidani ofKamo, Sakawa area (Loc. 4); Aptian.
Caestocorbula sp. cf. C. shikamai Hayami
PI. 77, Fig. 31.

Comapre with:1980. Caestocorbula shikamai Hayami, in
Hayami and Oji, Trans. Proc., Palaeont.
Soc. Japan, N.S., no. 120, p. 436, pI. 53,
figs. 8-12.
Materials:-KSG 3464 and KSG 3465, rightvalves, from Ujidani of Kamo, Sakawa.
Measurements (in mm.):-Specimens
KSG 3464, r. valve
KSG 3465, ditto

Length Height
16.3
13.5

9.8
9.6

Thickness
4.0
3.6

Remarks:-These specimens are probablyreferable to Caestocorbula shikamai Hay ami(1980) from the Choshi Group in central Japanjudging from its concentric riblets on the disk,
broadly prominent umbo and less rostrated pos-

Taxonomic results:-Bivalve species from theLower Cretaceous System in the Sakawa basin,
which were described in this part, are l!sted inTable 1. Most of the species are already known
from the other Cretaceous System in southwest
Japan (Amano, 1957b; Hayami, 1965~6;
Tashiro et al., 1980, 1981, 1985; Tashiro andKozai, 1984).
Correlation:-The Kurohara Formation (=Lower Monobegawa Group by Fukuji, 1941 and
Hirata, 1974) closely resembles and is correlatedwith the lower part of the Hibihara Formation(=Kaminiro Formation by Hujita, 1943, Aptian)in .the Monobe area, Shikoku, in having thebivalve fauna characterized by Pterotrigonia (s.s.)
pocilliformis, Nipponitrigonia kikuchiana and N.
sakamotoensis. The lower member (= Kaisekiyama Formation by Kurata, 1941; Ryoseki Formation by Hirata, 1974; "Kaisekiyama Formation" by Katto and Tashiro, 1981) of the Tosakamo Formation is also correlated with thelower part of the Hibihara Formation by theoccurrence of common bivalve species, e.g.,
Nuculopsis (Palaeonucula) ishidoensis, Portlandia
sanchuensis, Pterotrigonia (s.s.) pocilliformis,
Astarte (s.s.) subsenecta, A. (Trautscholdia)
minor, Caestocorbula minima and C. shikamai.
The bivalve fauna from the lower member of the
Tosakamo Formation some~hat differs fromthat of the Kurohara Formation by the occurrence of very shallow marine or subtidal bivalves,i.e., Nipponitrigonia spp., which have not beenknow from the former.
The Yotsushiro Formation (=Upper Monobegawa Group by Fukuji, 1941; Hirata, 1974) isundoubtedly correlated with the upper member(="Yunoki Formation" by Yamashita, 1961;"Yotsushiro Formation" by Katto and Tashiro,

386

Masayuki TASHIRO and Tomoko MATSUDA

1981; Upper Monobegawa Group by Fukuji,
1941; Hirata, 1974) of the Tosakamo Fonnation
because of the similarity in characteristics offacies and the presence of common bivalves andammonites. The Yotsushiro Fonnation and theupper member of the Tosakamo Fonnation are
also safely correlated with the upper part of the
Hibihara Fonnation (Upper Aptian to Albian)on account of the common occurrence of Inoceramus anglicus, Parvamussium tosaense andseveral ammonites (Dr. T. Matsumoto's infonnation). The upper member of Tosakamo Fonnation very resembles and is correlated with the
Tomochi Fonnation and the upper part ofHinagu Formation in central Kyushu in having
similar muddy facies and occurrence of common
bivalves, e.g., Parvamussium hinagense, P. tosaense and Cosmetodon tomochiensis.
The bivalve fauna from the Bunjo Fonnation(=eastem part of the Miyanohara Formation by
Yamashita, 1961; Hirata, 1974) is nearly identical to that of the Hagino Formation (Amano,
1957b; Aptian) in the Monobe area, Shikoku,
because nearly all of the species of bivalves andammonites are common between them. Although
the Bunjo and Kurohara (including the lower
member of the Tosakamo Formation) Formations are determinable to the Aptian in age by

Explanation of Plate 74
Figs. 1-3. Nueulopsis (Palaeonueula) ishidoensis (Yabe et Nagao) . . . . . . . . . . . . . . . Page 368
x 2, Loc. Ujidani of Kamo, Sakawa (4), Fig. 1, KSG 3479, gum cast of externalmould, Fig. 2, KSG 3481, Fig. 3, KSG 3480, gum cast of external mould.
Figs. 4-7. Portlandia sanehuensis (Yabe et Nagao) . . . . . . . . . . . . . . . . . . . . . . . . . Page 368
x 2, Loc. Ujidani of Kamo, Sakawa (4), Fig. 4, KSG 3486, gum cast of externalmould, Fig. 5, KSG 3484, internal mould, Fig. 6, KSG 3483, internal mould, Fig. 7,
KSG 3485, gum cast of external mould.
Fig. 8. Nemodon sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 370
x 2, Loc. Bunjo of Ochi, Sakawa (8), KSG 3494, gum cast of external mould.
Figs. 9-15. Cosmetodon tomoehiensis, sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . Page 369
Fig. 9, Paratype, KSG 3492, x 2, Loc. Kuroishi of Kamo, Sakawa (6), Figs. 10-11,
Holotype, KSG 3487, Loc. Kashiwagawa of Tomochi, Kumamoto Prefecture, Fig.
10, x 2, internal mould, Fig. 11, x 2.5, gum cast, Figs. 12-15, Paratypes, x 2.5 excluding Fig. 12 (x 2), Loc. same with above, Figs. 12 (KSG 3488) - 13 (KSG3489), internal moulds, Figs. 14 (KSG 3490) - 15 (KSG 3491), gum casts ofexternal moulds.
Figs. 16-18. Cueullaea obliquata (Amano) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 372
Figs. 16-17, xl, KSG 3497, gum casts of internal moulds, Fig. 18, x 2, KSG 3498,
gum cast of external mould, Loc. Bunjo of Ochi, Sakawa (8).
Figs. 19-20. Area (Eonavieula) prolata Amano . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 371
x 1, Fig. 19, KSG 3496, gum cast of external mould, Fig. 20, KSG 3495, internalmould, Loc. Bunjo of Ochi, Sakawa (8).
Figs. 21-22. Neithea (Neithea) syriaea amanoi Hayami . . . . . . . . . . . . . . . . . . . . . . Page 376
Fig. 21, x 1, KSG 3520, gum cast of external mould, Fig. 22, x 1.2, KSG 3521, external mould, Loc. Bunjo of Ochi, Sakawa (8).
Fig. 23. Pterotrigonia (?Seabrotrigonia) moriana (Yehara) . . . . . . . . . . . . . . . . . . . . Page 380
x 1.2, external mould, Loc. Bunjo of Ochi, Sakawa (8).
Figs. 24-27. Pterotrigonia (Pterotrigonia) pocilliformis (Yokoyama) . . . . . . . . . . . . . Page 379
Fig. 24 (KSG 3439), x 2, internal mould, Fig. 25 (KSG 3438), x 2.5, gum cast of
external mould, Fig. 27 (KSG 3437), x 1, gum cast of external mould, Loc. Ujidaniof Kamo, Sakawa (4), Fig. 26, KSG 3436, x 1.5, gum ast of external mould, Loc.
Kurohara (Sendatsuno) of Ochi, Sakawa (1).

TASHIRO and MATSUDA: Cretaceous bivalves from Sakawa

Plate 74

6

4

7

10

2

5

3

12

8

14

15

\

22

t .... _ . . . _ __ .

26

813. Cretaceous bivalves from Sakawa

387

Table 1. List of bivalve species from Sakawa.
SakawaSpeciesNuculopsis (Palaeonucula) ishidoensis
Portlandia sanchuensis
Cosmetodon tomochiensis
Nemodon sp.
Arca (Eonavicula) prolata
Cucullaea obliquata
Modiolus falcatus
Pinna (P.) sp. cf. P. (P.) robinaldina
Gervillaria haradae
Gervillia (Gervillia) sp. cf.
(G.) forbesiana
Isognomon sp.
Inoceramus anglicus
I. sp. aff. I. crippsi

K

TL

TU

B

HI

HA

0
0

@

0
X
X

X

0

0

X

X

0

0

0

0

0
0

@

0
@

0

0

@

0

@

X

0

0
X

0

X
X

I. sp.

Neithea (Neithea) syriaca amanoi
Parvamussium hinagense
P. tosaense
P. kattoi
Plicatula sp.
Nipponitrigonia kikuchiana
Pterotrigonia (Pterotrigonia) pocilliformis
P. (?Scabrotrigonia) moriana
P. (?S.) sp.
Lucinoma (?) sp.
Xenocardita amanoi
Astarte (Astarte) subsenecta
A. sp. cf. A. (Trautscholdia) minor
Leptosolen sp.
Protocardia (Protocardia) amanoi
Laevicardium? ishidoenseL.? corpulentum
Caestocorbula minima
C. sp. cf. C. shikamai

Y

Monobe

@

0
0

@

@
@

0
0
@

0
@

@

@

0
@

@

0

O?

0

0

@

@

0

0

@

@

0

X

0

0
0

O?
@

@

0

@

@

0

0

X: rare, 0: common, @: abundant, K: Kurohara F., Y: Yotsushiro F., TL: Lower'
Member of Tosakamo F., TU: Upper Member of Tosakamo F., B: Bunjo F., HI:
Hibihara F., HA: Hagino F.
the occurrence of ammonites, Chelloniceras spp.,
their bivalve faunas differ considerably fromeach other (see Table 1).

References
Amano, M. (1957a): Upper Cretaceous mollus-

can fossils from Shimo-koshiki-jima, Kyushu. Kumamoto Jour. Sci., Ser, B, vol. 2, no.
2, p. 51-75, pis. 1-2.
- - (1957b): The Lower Cretaceous fauna from
Hagino in southern Shikoku, Japan. Ibid.,
vol. 2, no. 2, p. 77-121, pIs. 1-2.
Conrad, T. A. (1862): Description of new genera,
subgenera and species of Tertiary and388

Masayuki TASHIRO and Tomoko MATSUDA

Recent shells. Acad. Nat. Sci., Philadelphia,
Jour. 1862, p. 284-291.
Dhondt, A. V. (1973): Systematic revision of thesubfamily Neitheinae (Pectinidae, Bivalvia,
Mollusca) of the European Cretaceous.
Mem. Inst. Roy. Sci. Nat. Belgique, no. 176,
p. 1-101, pIs. 1-5.
Fukuji, S. (1941): Geology of the Ochi basin,
province of Tosa, Shikoku. Jour. Geol. Soc.
Japan, vol. 48, no. 579, p. 547-559.
Hayami, 1. (1965): Lower Cretaceous marine
pelecypods of Japan, Pt. 1. Mem. Fac. Sci.,
Kyushu Univ., Ser. D, Geol., vol. 15, no. 2,
p. 221-349, pIs. 27-52.
- - (1966a): Lower Cretaceous marine pelecypods of Japan, Pt. 2. Ibid., vol. 17, no. 2, p.
73-150, pIs. 7-12.
--(1966b): Lower Cretaceous marine pelecypods of Japan, Pt. 3. Ibid., vol. 17, no. 3, p.
151-249, pIs. 22-26.
--(1975): A systematic survey of the Mesozoic
Bivalvia from Japan. Univ. Mus., Univ.
Tokyo, Bull., no. 10, p. 1-249, pIs. 1-10.
--and Noda, M. (1977): Notes on the morphology of Neithea (Cretaceous pectinids)with taxonomic revision of Japanese species.
Trans. Proc., Palaeont. Soc. Japan, N.S., no.

105, p. 27-54, pIs. 5-6.
--and Oji, T. (1980): Early Cretaceous Bivalvia
from Choshi district, Chiba Prefecture,
Japan. Ibid., no. 120, p. 419-448, pIs. 5153.
Hirata, M. (1974): Mesozoic fossils in Kochi
Prefecture (excluding the Ryoseki flora).
Hirata's Institute of Geology, Kochi, 68 p.,
16 pIs.
Hujita, A. (1943): Geology of the Odochi area,
Shikoku. Jour. Geol. Soc. Japan, vol. 50, p.
207-215.
Katto, J. and Tashiro, M. (1978): A study on themolluscan faunas of the Shimanto Terrain,southwest Japan, Part 1: On the bivalve
fauna of the Doganaro Formation in Susaki
area, Kochi Prefecture. Res. Rep., Kochi
Univ., vol. 27, p. 143-150, pIs. 1-2.
--and - - (1981): On the Cretaceous system in the Sakawa area, Kochi, Japan. Ibid.,
vol. 30, p. 109-119.
Kobayashi, T. (1957): Nipponitrigonia and
Rutitrigonia in Japan. Trans. Proc., Palaeont. Soc. Japan, N.S., no. 26, p. 51-61, pIs.
10-11.
--and Suzuki, K. (1939): The brackish Welden
fauna of the Yoshimo beds in Provo Nagato,

Explanation of Plate 75
Figs. 1-5,13. Gervillaria haradae (Yokoyama) . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 373
Fig. 1 (KSG 3507), x 1, gum cast of external mould, Figs. 5 (gum cast of internalmould), 13 (internal mould), KSG 3506, x 1, Loc Bunjo of Ochi, Sakawa (8), Fig.
2 (KSG 3504), x 1, internal mould, Fig. 3, x 1, KSG 3508, internal mould, Loc.
Ujidani of Kamo, Sakawa (4), Fig. 4, x 1.5, internal mould, Loc. Yotsushiro ofOchi, Sakawa (9).
Figs. 6, 12. Modiolus falcatus Amano . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 373
Fig. 6, x 1.2, KSG 3499, gum cast of external mould, Fig. 12, x 2, KSG 3500, internal mould, Loc. Bunjo of Ochi, Sakawa (8).
Fig. 7. Isognomon sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 375
x 0.8, KSG 3512, gum cast of internal mould, Loc. Bunjo of Ochi, Sakawa (8).
Fig. 8. Gervillia (Gervillia) sp. cf. G. (G.) forbesiana d'Orbigny . . . . . . . . . . . . . . . . . Page 374
x 1.2, KSG 3508, gum cast of external mould, Loc. Bunjo of Ochi, Sakawa (8).
Fig. 9. Pinna (Pinna) sp. cf. P. (P.) robinaldina d'Orbigny . . . . . . . . . . . . . . . . . . . . Page 373
x 1, KSG 3502, gum cast of external mould, Loc. Bunjo of Ochi, Sakawa (8).
Figs. 10-11. Xenocardita amanoi (Hayami) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 380
x 4, Fig. 10 (KSG 3442), Fig. 11 (3446), gum casts of external moulds, Loc. Bunjo
of Ochi, Sakawa (8).
Fig. 14. Astarte (Astarte) subsenecta Yabe et Nagao . . . . . . . . . . . . . . . . . . . . . . . . Page 381
x 2.5, gum cast of external mould, Loc. Ujidani of Kamo, Sakawa (4).

TASHIRO and MATSUDA: Cretaceous bivalves from Sakawa

Plate 75

13
," ,

5
12

"

'.

813. Cretaceous bivalves from Sakawa
Japan. Japan. Jour. Geol. Geogr., vol. 16,
nos. 3-4, p. 213-224, pIs. 13-14.
--and Nakano, M. (1957): On the Pterotrigoniinae. Ibid., vol. 28, no. 4, p. 219-238, pIs.
16-17.
Kurata, N. (1940): Geology of the Togano basinof Sakawa. Jour. Geol. Soc. Japan, vol. 47,
no. 567, p. 507-516.
Matsukuma, A. (1979): Glycymeridid bivalvesfrom Japan and adjacent areas, Pt. 1. Venus(Japan. Jour. Malac.), vol. 38, no. 2, p. 95128.
Matsumoto, T. and Harada, M. (1964): CretaceouS stratigraphy of the Yubari dome,
Hokkaido. Mem. Fac. Sci., Kyushu Univ.,
Ser. D, Geol., vol. 15, no. 1, p. 79-115,
pis. 9-11.
- - , Hayami, I. and Asano, K. (1963): A surveyof fossils from Japan illustrated in classicalmonographs, Part VII. Palaeont. Soc. Japan,
25th Anniv. Vol., p. 27-32, pIs. 44-51.
Nagao, T. (1934): Cretaceous Mollusca from the
Miyako district, Honshu, Japan. Jour. Fac.
Sci., Rokkaido Imp. Univ., Ser. 4, vol. 2, no.
3, p. 177-277, pIs. 23-39.
Shikama, T. and Suzuki, S. (1972): Stratigraphy
and tectonic development mainly of Cretaceous formations of Choshi Peninsula, Chiba
Prefecture. Sci. Rept., Yokohama Nat. Univ.,
Ser. 2, vol. 19, p. 133-157, pIs. 4-6.
Shinohara, I. (1951): Illustrated handbook offossils from Shikoku. 30 p., 13 pIs. (Shumino-chigaku ).
Tamura, M. (1959): Taxodonta and Isodonta
from the Upper Jurassic Sakamoto Formation in central Kyushu, Japan. Trans. Proc.,
Palaeont. Soc. Japan, N.S., no. 34, p. 5365, pI. 6.
--(1973): Two new species of Lower Cretaceous Parvamussium from Kyushu, Jap"anand Sarawak Borneo. Geol. Pal. Southeast
Asia, vol. 11, p. 119-124, pI. 17.
Tashiro, M. (1976): Bivalve faunas of the Cretaceous Himenoura Group in Kyushu. Palaeont. Soc. Japan, Spec. Pap., no. 19, p. 1121, pIs. 1-12.
--(1985): The bivalve faunas and their biostratigraphy of the Cretaceous in Japan.
Geol. Soc. Japan, Spec. Pap., no. 26, p. 4375.
--and Kozai, T. (1984): Bivalve fossils from389

the type Monobegawa Group (Part 1). Res.
Rep., Kochi Univ., vol. 32, p. 259-293, pIs.
1-4.
- - , - - , Okamura, M. and Katto, J. (1980):
A biostratigraphical study of the Lower
Cretaceous formations of Monobe area,
Kochi Prefecture, Japan. Geol. Paleont.
Shimanto Belt, Taira and Tashiro eds.,
Kochi, p. 71-82, pIs. 10-11.
and Matsuda, T. (1983): A study of thepterotrigoniae from Japan, Part 1. Mem.
Fac. Sci., Kochi Univ., Ser. E, Geol., vol. 4,
p. 13-52, pIs. 1-13.
- , - - and Tanaka, H. (1985): Upper
Albian bivalve fauna of the Haidateyama
Group in Kyushu. Ibid., vols. 5-6, p. 1-23,
pis. 1-3.
- , Takahashi, K. and Katto, J. (1981): On thegeological age of the Doganaro Formationof the Shimanto Belt in Kochi, Japan. Jour.
Geol. Soc. Japan, vol. 88, no. 3, p. 203205.
Vokes, H. E. (1946): Contributions to the paleontology of the Lebanon mountains, Republic of Lebanon; Part 3, the pelecypod faunaof the 'Olive locality' (Aptian) at Abeih.
Amer. Mus. Nat. Rist. Bull., vol. 87, art. 3,
p. 139-216, pIs. 1-10.
Woods, H. (1899-1903): A monograph of theCretaceous Lamellibranchia of England.
vol. 1, 227 p., 42 pIs., Palaeontogr. Soc.
London.
-(1904-1913): A monograph of the Cretaceous Lamellibranchia of England. vol. 2,
473 p., 62 pIs., Ibid.
Yabe, H. (1927): Cretaceous stratigraphy of theJapanese islands. Sci. Rep., Tohoku Imp.
Univ., Ser. 2, vol. 11, no. 1, p. 27-100, pIs.
3-9.
- - , Nagao, T. and Shimizu, S. (1926): Cretaceous Mollusca from the Sanchu graben in
the Kwanto mountainland, Japan. Sci.
Rep., Tohoku Imp. Univ., Ser. 2, vol. 9, no.
2, p. 33-76, pIs. 12-15.
Yamashita, N. (1961): Geological map of Kochi
Prefecture (1/200,000), fig. 5; Geology ofOchi basin and Y okokurayama in Kochi.
Yehara, S. (1915): The Cretaceous trigoniae
from Miyako and Hokkaido. Sci. Rep.,
Tohoku Imp. Univ., Ser. 2, vol. 2, no. 2, p.
35-44, pIs. 1-2.

390

Masayuki TASHIRO and TomQko MATSUDA--(1923): Cretaceous trigoniae from southwest Japan. Japan. Jour. Geol. Geogr., vol.
2, no. 3, p. 59-84, pIs. 8-13.
--(1927): Faunal and stratigraphical study of
the Sakawa basin, Shikoku. Ibid., vol. 5,
nos. 1-2, p. 1-40, pIs. 1-5.

Yokoyama, M. (1890): Versteinerungen aus derjapanischen Kreide. Palaeontographica, vol.
36, p. 159-202, pIs. 18-25.
--(1891): On some Cretaceous fossils from
Shikoku. Jour. Coli. Sci., Imp. Univ. Tokyo,
Sec. 2, vol. 4, no. 2, p. 357-366, pl. 40.

Bunjo :i(iIil;, Hagino *X!!!f, Hibihara B,ltlli{, Hirooka 5L-IIfil, Kaisekiyama 1i':fi(lj, Kashiwagawa#1)11, Kamo 1Jn&, Kuroishi !!.!.:fi, Kurohara m.I*, Monobe ~$, Ochi ~~, Sakawa ft;:}fI, To
mm, Ujidani '¥i'Mt, Yotsushiro gg-y 8, Yamanokami (lj/ ftlJ.

Explanation of Plate 76
Figs. 1-2, 10. Parvamussium kattoi, sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 378
Figs. I, 10, Paratypes, Fig. I, x 1.5, KSG 3533, gum cast of external mould, Fig.
10, x 2, KSG 3532, gum cast of internal mould, Fig. 2 Holotype, x 2.5, KSG 3531,
gum cast of external mould, Loc. Kurohara of Ochi, Sakawa (2).
Figs. 3, 5--£, 11-12. Parvamussium tosaense, sp. nov . . . . . . . . . . . . . . . . . . . . . . . Page 377
x 2, Fig. 3, Paratype, KSG 3530, gum cast of external mould, Loc. Kuroishi ofKamo, Sakawa (6), Fig. 5, Paratype, KSG 3528, gum cast of internal mould, Fig.
6, Holotype, KSG 3526, gum cast of internal mould, Fig. 11, Paratype, KSG 3529,
gum cast of imperfect external mould, Loc. Yotsushiro of Ochi, Sakawa (2), Fig.
12, Paratype, KSG 3527, gum cast of internal mould, Loc. Kurohara of Ochi,
Sakawa (6).
Fig. 4. Cosmetodon tomochiensis, sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 369
Paratype, KSG 3493, x 2, internal mould, Loc. Kuroishi of Kamo, Sakawa (6).
Figs. 7-9,13. Parvamussium hinagense Tamura . . . . . . . . . . . . . . . . . . . . . . . . . . Page 376
Figs. 7-8, KSG 3525, x 1.5, Fig. 8, gum cast of external mould, Fig. 9, KSG 3523,
x 2, gum cast of internal mould, Fig. 13, KSG 3524, x 1.5, gum cast of externalmould, Loc. Kuroishi of Kamo, Sakawa (6).
Fig. 14. Plicatula sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 378
x 2, KSG 3534, gum cast of internal mould, Loc. Bunjo of Ochi, Sakawa (8).
Figs. 15-16,19,21-23. Inoceramus anglicus Woods . . . . . . . . . . . . . . . . . . . . . . . Page 375
x 1, exluding Fig. 21 (x 1.5), Figs. 16, 22, gum casts of external moulds of KSG
3513, Fig. 19, KSG 3514, Fig. 21, KSG 3515, Fig. 23, KSG 3516, posterior dorsal
view of conjoined valves, Loc. Kurohara of Ochi, Sakawa (3).
Figs. 17-18. Inoceramus sp. aff. I. crippsi Mantell . . . . . . . . . . . . . . . . . . . . . . . . . Page 375
x 1, Fig. 17, KSG 3517, internal mould and lateral view (Fig. 18) of external gum
cast (Fig. 17), Loc. Kurohara of Ochi, Sakawa (3).
Figs. 20, 24. Inoceramus sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 376
x 1.2, Fig. 20, KSG 3518, gum cast of external mould, Fig. 24, gum cast of external mould, Loc. Kurohara of Ochi, Sakawa (3).

Plate 76

TASHIRO and MATSUDA: Cretaceous bivalves from Sakawa

3

7

2

4
5

6

8

f!.~
.,; ~

10

..

.

..

.
./

12

9

14

13

19
20

21

22

/

813. Cretaceous bivalves from Sakawa

391~~JJit.tii:JIIPIJ mJmO)T(flH~3!1li*i&:=fj(J:l {t;;fi: ~~~{t.JlIPIJ· ~~IIIJ O)Tifll8!1li*b' i?~,:,.ni? O)? 'b 4 ¥Ifil!
(Cosmetodoll tomochiensis, Parvamussium kattoi, P. tosaense, Protocardia (Protocardia)
amanoi) a-~ltli, ~.1:'iffli¥l'B*O) Barremian b'i? Albian t;::.q:HI!!(i¥]t.l:=fj(~lib' IJ "C~G
b~, -to)::kfflHHt, tii:Jll:lt!rnb'i?lt!lfl6'.>-C¥ll15-~.nG t O)"{'~Go it.:, ,:,.ni?O)=t:XJ:llt,
i?.nt.:=fj(~ {t;;fia-~W Ltd:j!j:lf,; 22 ~ 33 :flRb~~~Jj~.nt.:O)"{'~c1t&;i" Go~~~~ifll~~O)Tifll8!1li*O)B~~~c~~~0)-t.n~.n0)=t:X~7*-7a-m~i"G~~
t;::.::k~Jj"{'~ G O)"{', tii:JII~:Jj C ~ifll~:JjO)Tifll8!1li*a-%J"~i"GJ::K t m:~t.l:tt;jSf"{'~GoEBf\;lEz • t~EB~T392

Masayuki TASHIRO and Tomoko MATSUDA

Explanation of Plate 77
Figs. 1-7. Laevicardium? corpulentum (Amano) . . . . . . . . . . . . . . . . . . . . . . . . . . Page 383
Gum cast of external mould (Fig. I, KSG 3454, x 1.5) and surface ornamentation(Fig. 2, x 2), intrnal mould (Fig. 3, KSG 3456, x 1.5) and its dorsal view (Fig. 4,
x 1.5) and anterior view (Fig. 5, x 1.5), Fig. 6, internal mould, KSG 3455, x 1.5,
Fig. 7, surface ornamentation of gum cast of external mould, KSG 3457, x 3, Loc.
Bunjo of Ochi, Sakawa (8).
Figs. 8-9. Laevicardium? ishidoense (Yabe et Nagao) . . . . . . . . . . . . . . . . . . . . . . . Page 383
Fig. 8, lateral view (KSG 3452, x 2) and surface ornamentation in gum cast of external mould (Fig. 9), KSG 3453, x 3, Loc. about 800 m north of Hirooka of
Kamo, Sakawa (5).
Figs. 10-14. Protocardia (Protocardia) amanoi, sp. nov. . . . . . . . . . . . . . . . . . . . . . Page 382
x 1.6, Fig. 10, Holotype, KSG 3448, gum cast of imperfect external mould, andposterior view (Fig. 11), Figs. 12-14, Paratypes, KSG 3451 (Fig. 12), posteriorview of gum cast of external mould, KSG 3450 (Fig. 13), gum cast of externalmould and KSG 3449 (Fig. 14), posterior view of gum casts of external moulds,
Loc. Bunjo of Ochi, Sakawa (8).
Figs. 15-16. Lucinoma? sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 380
Fig. 15, x 1.6, KSG 3440, gum cast of external mould, Fig. 16, x 2, KSG 3441,
gum cast of external mould, Loc. Ujidani of Kamo, Sakawa (4).
Figs. 17-19, 25-26. Astarte (Astarte) subsenecta Yabe et Nagao . . . . . . . . . . . . . . . Page 381
Fig. 17, x 2, KSG 3476, internal mould, Fig. 18, x 1.2, KSG 3475, gum cast of external mould, Loc. about 800 m north of Hirooka, Kamo, Sakawa (5), Figs. 19,
25-26, x 1.2, Fig. 19, KSG 3474, gum cast of external mould, Fig. 25, KSG 3473,
gum cast of internal mould, Fig. 26, KSG 3472, gum cast of internal mould, Loc.
Ujidani of Kamo, Sakawa (4).
Figs. 20-24. Astarte sp. cf. Astarte (Trautscholdia) minor Nagao . . . . . . . . . . . . . . . Page 381
x 2.2, Fig. 20, KSG 3469, external mould, Fig. 21, KSG 3471, external mould,
Fig. 22, gum cast of imperfect external mould, Fig. 23, KSG 3466, internal mould,
Fig. 24, KSG 3468, internal mould, Loc. Ujidani of Kamo, Sakawa (4).
Figs. 27-30. Caestocorbula minima Hayami . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 384
x 2.2, Fig. 27, KSG 3458, internal mould, Fig. 28, KSG 3459, internal mould, Fig.
29, KSG 3460, internal mould, Fig. 30, KSG 3463, internal mould, Loc. Ujidani ofKamo, Sakawa (4).
Fig. 31. Caestocorbula sp. cf. C. shikamai Hayami . . . . . . . . . . . . . . . . . . . . . . . . . Page 385
x 1.5, KSG 3464, Loc. Ujidani of Kamo, Sakawa (4).

TASH IRO and MATSUDA : Cretaceous bivalves from Sakawa

Plate 77

6
3

9

5
7

15

16

11

10

17

12

"
19

18

22

23

20
31

27

28

29rM1 30

24

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 142, pp. 393-399, pI. 78, June 30,1986

814. STRIATIFERA AND GIGANTOPRODUCTUS FROM THE
LOWER CARBONIFEROUS OF FUKUJI, CENTRAL JAP AN*
JUN-ICHI TAZAWA
Department of Earth Sciences, Niigata University, Niigata 950-21
and
MAKOTOKATO
Department of Geology and Mineralogy, Hokkaido University, Sapporo 060

Abstract. Striatifera striata (Fischer de Waldheim, 1837) and Gigantoproductus sp. are described from the lowest part of the Ichinotani Formation (Upper
Visean) in Fukuji, Central Japan. S. striata is a large-sized linoproductid, distributedin the Upper Visean and Lower Namurian (rarely Upper Tournaisian) of the Old
World, viz. Britain, France, Belgium, Germany, weastern part of the U.S.S.R.,
South China and Japan.

(Fischer de Waldheim, 1837) and Gigantoproductus sp. are now disclosed from the collections mentioned above.
S. striata is the type species of the genus
Striatifera Chao, 1927. And it has been known
from the Upper Visean and Lower Namurian(Serpukhovian) of Britain, France, Belgium, Germany, western part of the Soviet Union, South
China and Japan (Hina, Omi and Fukuji), except
for the sole Upper Tournaisian occurrence in the
Moscow Basin. The geographical distribution ofthis species is summarized and shown in Text-fig.
2. On the other hand, shells referred to the genus
Gigantoproductus Prentice, 1950 have been recorded from the Visean (mostly Upper Visean)and Lower Namurian of Northeastern Africa,
Europe, Asia, Australia and North America (e.g.
Sarytcheva and Sokolskaja, 1952; Muir-Woodand Cooper, 1960; Legrand-Blain, 1973), al'though the occurrences from the last two regions
are rare. Gigantoproductus sp. of Fukuji is morphologically close to G. irregularis (Y anishevsky,

Introduction
Occurrence of some productoid brachiopods
in the Carboniferous rocks of Fukuji, Central
Japan, was first noticed by Igo (1956, p. 223).
Recently in his paper on the upper Palaeozoic
stratigraphy of the Fukuji district, Niikawa(1980, p. 28) recorded Striatifera and Gigantoproductus from the lowest part of the Carboniferous Ichinotani Formation. However, these
species have never been figured or described.
This paper reviews and describes the Niikawa's
material collected by Dr. Y. Okazaki and somespecimens made by Tazawa, both from the same
locality of Igo, midstream in the Ichinotani
Valley (Text-fig. 1), at which place fossiliferous
black limestone of about 5 m thick, the lowest
Ichinotani Formation is cropped out.
Two large-sized productoids, Striatifera striata*Received March 11, 1985; read February 3,
1985 at University of Tokyo.
393

394

Jun-ichi T AZA WA and Makoto KA TO

1954), a Russian Serpukhovian species.
The brachiopods from the lowest part of the
Ichinotani Fonnation suggest that the age of tIie
unit may be Late Visean to Early Namurian. Thisestimation nearly accords with previous opinion,a Late Visean age, based on fusulinids and corals(Igo, 1957; Minato and Kato, 1957; Fujimotoand Igo, 1958; Kato and Niikawa, 1977; Niikawa, 1978). In conclusion, we regard the black
limestone occupying the basal, lower 5 m part of
the Ichinotani Formation as an Upper Visean
deposits in the Fukuji district.
The specimens treated in the present study
are housed in the Institute of Geology and Palaeontology, Faculty of Science, Tohoku University, Sendai.
Description of species
Family Linoproductidae Stehli, 1954
Text-fig.!.

Map showing the fossil locality.

Subfamily Striatiferinae Muir-Wood and Cooper,
1960
Genus Striatifera Chao, 1927

Text-fig. 2. Distribution of Striatifera striata (Fischer de Waldheim). References to the numbers appended to solid triangles are in the text.

814. Carboniferous brachiopods of Fukuji
Striatifera striata (Fischer de Waldheim, 1837)

PI. 78, Figs. 1-6.
Mytilus striatus Fischer, 1837, p. 181, pI. 19, fig.

4.
Productus striatus (Fischer): de Koninck, 1843
pars, p. 169, pI. 6, figs. 10a-d only; 1847
pars, p. 30, pI. 1, figs. 1a-b only; Davidson,
1861 pars, p. 139, pI. 34, figs. 1, 3-5; pI. 53,
fig. 4 only; Grober, 1908, p. 232, pI. 26, figs.
6-7; pI. 30, fig. 1; Vaughan (in Matley andVaughan, 1908), p. 466, pI. 50, fig. 2;Mansuy,
1912, p. 88, pI. 16, figs. 8a--e; Yanishevsky,
1918, p. 29, pI. 1, fig. 8; pI. 6, fig. 8; Hayasaka, 1924, p. 29, pI. 5, fig. 7.
Striatifera striata (Fischer): Chao, 1927, p. 95,
pI. 9, figs. 4-6; pI. 10, fig. 6; Sarytcheva,
1937, p. 24, 107, pI. 1, figs. 1-5; pI. 2, figs.
1-3; text-figs. 4-7; Sarytcheva (in Sarytcheva and Sokolskaja, 1952), p. 118, pI. 22,
fig. 151; Muir-Wood and Cooper, 1960, pI.
126, figs. 1-2: Litvinovich (in Litvinovich,
Aksenova and Razina, 1969), p. 195, pI. 20,
figs. 2-3; Barchatova, 1970, p. 126, pI. 1, fig.
9; Gandl, 1970, p. 74, pI. 1, fig. 7; Kalashnikov, 1974, p. 79, pI. 24, fig. 5; Hase andYokoyama, 1975, pI. 17, figs. 2-5;Volginand Kushnar, 1975, p. 54, pI. 5, figs. 4-5;
Yang, Ni, Chang and Zhao, 1977, p. 367, pI.
145, fig. 3; Feng and Jiang, 1978, p. 264, pI.
96, fig. 1; Yang, 1978, p. 11 7, pI. 26, fig. 6;
pI. 30, figs. 1a-b; Liu, Tan and Ding, 1982, p.
188, pI. 136, fig. 7; Legrand-Blain, Delvolveand Perret, 1983, p. 306, pI. 2, figs. 3-5.
Productus (Linoproductus) striatus (Fischer):
Paeckelmann, 1931 pars, p. 200, pI. 20, fig. 2
only.
Striatifera striata var. striata (Fischer) emend.
Sarytcheva: Lapina, 1957, p. 52, pI. 6, fig. 1.
Striatifera sp. Niikawa, 1980, p. 28.
non Striatifera striata (Fischer): Tazawa, 1981,
p. 73, pI. 5, figs. 6a-e.
Type :-The original specimen of Fischer from"des sables de la colline Ii l'ouest d'Arkhangelsky" appear to be lost (Legrand-Blain, Delvolveand Perret, 1983, p. 307). No type specimen has
yet been selected. However, a detailed description and some fine figures of S. striata were given
by Sarytcheva (1937, p. 24,107, pI. 1, figs. 1-5;

395

pI. 2, figs. 1-3; text-figs. 4-7), based on material
from the Upper Visean and Serpukhovian of the
Moscow Basin. The Russian specimens are stored
in the Palaeontological Museum, Academy of
Sciences, Moscow.
Material:-Six pedicle valves, collected by Y.
Okazaki and J. Tazawa from the black limestone
beds of the lowest Ichinotani Formation in the
middle part of the Ichinotani Valley, Fukuji,
Kamitakara-mura, Yoshiki-gun, Gifu Prefecture,
Central Japan: IGPS colI. cat. nos. 9888898893.
Description:-Shell large for genus, elongate
trigonal to elongate oval in outline, with visceraldisc tapering to umbo; greatest width occurring
three-quarters length of shell or a little anterior
to that; length 104 mm, width 72 mm in the best
preserved specimen (IGPS colI. cat. no. 98888);
length 128 mm, width 78 mm in the largest
specimen (IGPS colI. cat. no. 98892).
Pedicle valve slightly convex in lateral profile,with greatest convexity just anterior to umbo,and not geniculated; anterior profile with broad,flattened venter and steep lateral slopes. Umbo
acute, not incurved. Ears damaged in the present
specimens. External ornament consisting of fine,
flexuous costae and irregular, weak concentricrugae; costae having a density of 15-16 per 10mm at about midvalve. Spine bases not observed.
Remarks :-The specimens from Fukuji are
identical in size and shape to Striatifera striata(Fischer de Waldheim, 1837), which is characterized by its large, elongate, often mytiliform (ofpelecypod) shell with less convex pedicle valve.
But they have slightly coarser costae on thepedicle valve, comparing the typical specimensfrom the Upper Visean and Serpukhovian of the
Moscow Basin (18-29 costae in 10 mm width,
after Sarytcheva, 1937, p. 27).
S. magna Yanishevsky, 1934 emend. Sarytcheva, 1937 is a large, coarse-costate species
comparable with S. striata, but differs from thelatter in its more convex and broader pedicle
valve.
S. coraesimilis Sarytcheva, 1937 somewhat
resembles S. striata in size and shape, but differs

Jun-ichi TAZAWA and Makoto KATO

396

in having several large spine bases on the venter.
S. angusta (Y anishevsky, 1910) is distinguished from the present species by its subcylindrical pedicle valve with ill-defined ears (seeSarytcheva, 1937, pI. 1, figs. 6a-c).
Shells identified as S. striata from the Visean
Karoyama Formation of the southern Kitakami
Mountains, Northeast Japan (Tazawa, 1981, p.
73, pI. 5, figs. 6a-e), are distinguished from thepresent species by their much coarser costae on
the pedicle valve.
Stratigraphical distribution:-Upper Visean to
Lower Namurian (Serpukhovian). The only one
exception, Upper Tournaisian occurrence wasrecorded by Sarytcheva and Sokolskaja (1952,
p. 254) from the Chernyshinsky Horizon of the
Moscow Basin, U.S.S.R.
Geographical distribution:-Shown in Textfig. 2: Loughshinny, County Dublin, Ireland (1);Isle of Man (2); Lowick, Northumberland, England (3); Settle, Yorkshire, England (4); Park
Hill, Longnor, Derbyshire, England (5); Central
French Pyrenees, France (6); Vise, Belgium (7);Frankenwald, Bavaria, Western Germany (8);Moscow Basin, U.S.S.R. (9); Northern Timan,
U.S.S.R. (10); North Ural Mountains, U.S.S.R.
(11); Central Ural Mountains, U.S.S.R. (12);Central Kazakhstan, U.S.S.R. (13); Central Tien
Shan, U.S.S.R. (14); Fergana, U.S.S.R. (15);
Yunnan, South China (16); Guizhou, South
China (17); Hunan, South China (18); Guangxi,
South China (19); Hina, Okayama Prefecture,
Southwest Japan (20); Fukuji, Gifu Prefecture,
Central Japan (21); Omi, Niigata Prefecture,
Central Japan (22).
Family Gigantoproductidae Muir-Woodand Cooper, 1960
Subfamily Gigantoproductinae Muir-Woodand Cooper, 1960

Material:-one imperfect pedicle valve, IGPS
coli. cat. no. 98894, collected by Y. Okazaki
from the same horizon and the same locality ofthe shells of S. striata described above.
Remarks:-The single pedicle valve specimen,
lacking the posterior portion, can be referred to
the genus Gigantoproductus Prentice, 1950 on
account of its size, shape and external ornament.
The shell is of small size for the genus and mo~­erately transverse; length is uncertain but morethan 50 mm, width is about 76 mm. The pedicle
valve is strongly convex in lateral profile, having
a very shallow sulcus, and is ornamented byregular costae with a density of 9 per 10 mm at
about the midvalve. There are numerous fine
growth lines over the valve, but no spine bases
or flutings are observed.
The Fukuji specimen most resembles theshells of G. irregularis (Yanishevsky, 1954), described and figured by Sarytcheva (in Sarytcheva
and Sokolskaja, 1952, p. 132, pI. 36, fig. 182)
from the Serpukhovian of the Moscow Basin in
size, shape and external ornament. But the poor
preservation of this material makes the accuratecomparison difficult.
G. edelburgensis (Phillips, 1836) differs fromthe present species in its larger size, coarser
costae and in having several large spine bases on
the venter.

Acknowledgements
We wish to thank Dr. Yoshihiko Okazaki of
Kitakyushu Museum of Natural History forproviding specimens he collected; Prof. Koji
Nakamura of Hokkaido University for helpful
suggestions; Prof. Hisayoshi Igo of the Universityof Tsukuba for information on the fossil locality;
and Mr. Shohei Otomo of Tohoku University forphotography.

Genus Gigantoproductus Prentice, 1950
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Gigantoproductus sp.

PI. 78, Fig. 7.
Gigantoproductus sp., Niikawa, 1980, p. 28.

n. ;Barchatova, V. P.
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ouocTpaTurpa<j>ulI KapooHa U HUJKHeH llepMU
CeBepHoro TUMaHa. Tp. BHHPPH, Bhlll.283,
p. 1-228, pis. 1-21.

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1,2, p. 79-157, pIs. 1-4.
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r. r. H Pa3HHa, T. n. : CTpaTHrpacJlHH H
JlHTOJlOrHH OTJlOmeHHH HHmHero Kap60Ha
3ana.llHOH lJaCTH UeHTpaJlbHOrO Ka3axCTaHa.
448 p., 72 pIs., He.llpa, MocKBa.
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MatIey, C. A. and Vaughan, A. (1908): The Carboniferous rocks at Loughshinny (County
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64, no. 255, p. 413-474, pis. 49-50.
Minato, M. and Kato, M. (1957): On the Carboniferous coral zones at Fukuji, Gifu Prefecture, Central Japan. Proc. Japan Acad., vol.

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Jun-ichi TAZA WA and Makoto KATO

33, no. 9, p. 547-552.
Muir-Wood, H. M. and Cooper, G. A. (1960):
Morphology, classification and life habitsof the Productoidea (Brachiopoda). Geol.
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Niikawa, I. (1978): Carboniferous and Permian
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no. 4, p. 533--,nO, pIs. 1-14.
(1980): Geology ad biostratigraphy of the
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Paeckelmann, W. (1931): Die Brachiopoden desdeutschen Unterkarbons, 2 Teil: Die Productinae und Productus-iihnlichen Chonetinae.
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436-438.
Sarytcheva, T. G.
(1937):
CapbI'IeBa, T. r.:
HloKHeKaM eH HOY r OJI bHble
np0.llYKTH.llbi
OO.llMOCKOBHoro BacceiiHa (PO.llbl Striatifera,-

Linoproductus H Cancrinella). Tp. nl1H, T.
6, Bblll. 1, p. 1-123, pIs. 1-7.
and Sokolskaja, A. N. (1952):
Capbl'leBa,
T. r. H COKOJlbCKalI, A. H.: Ollpe.lleJlHTeJlb

llaJle030iicKHX
6paXHOllO.ll
OO.llMOCKOBHOii
KOTJlOBHHbI. Tp. nl1H, T. 38, p. 1-303, pIs.

1-71.
Stehli, F. G. (1954): Lower Leonardian Brachiopoda of the Sierra Diablo. Bull. Amer. Mus.
Nat. Hist., vol. 105, art. 3, p. 262-358, pIs.
17-27.
Tazawa, J. (1981): An Early Carboniferous
brachiopod fauna from the Karoyama Formation in the Kitakami Mountains, Northeast Japan. Saito Ho-on Kai Mus. Nat. Hist.,
Res. Bull., no. 49, p. 63-79, pI. 5.
Volgin, V.1. and Kushnar, L. V. (1975): BOJlrHH,
B. YI. H KywHapb, JI. B.: 003.llHeBH3eiicKHe
6paXHOllO.llbl
H .llBycTBOp'laTble
MOJlIOCKHIO>KHoii <l>epraHbI. 112 p., 10 pIs., i13.ll-BO.
JIeHHHrpa.ll. YH-Ta., JIeHHHrpa.ll.

Yang, D., Ni, S., Chang, M. and Zhao, R. (1977):
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Yang, S. (1978): Lower Carboniferous brachiopods of Guizhou Province and their stratigraphic significance. Prof Pap. Strat. Palaeont., no .. 5, p. 78-142, pIs. 17-39 (inChinese).
Yanishevsky, M. E. (1918): 51HHweBcKHii, M.3.:
MaTepHaJlbl K H3Y'IeHHIO HH>KHeKaMeHHoyrOJlbHOii lfIaYHbl <l>epraHbl.
Tp. reoll. KOM.,
H. C., BbIll. 162, p. 1-145, pIs. 1-8.

Explanation of Plate 78(All figures are natural size.)
Figs. 1--ti. Striatifera striata (Fischer de Waldheim)
Ventral views of pedicle valves. 1: IGPS colI. cat. no. 98888; 2: IGPS coll. cat. no. 98893;
3: IGPS coll. cat. no. 98889; 4: IGPS colI. cat. no. 98891; 5: IGPS coll. cat. no. 98890;
6: IGPS coll. cat. no. 98892.
Fig. 7. Gigantoproductus sp.
Anterior view of pedicle valve, IGPS colI. cat. no. 98894.

TAZA WA and KATO: Carboniferous brachiopods from Fukuji

2

Plate 78

399

814. Carboniferous brachiopods of Fukuji
Fukuji mij(g, Gifu dJit-$., Hina S iff, Ichinotani -Q);fr, Kamitakara-mura J:$:t-t. Karoyama bn

1iW, Kitakami ~tJ:, Niigata ~~, Okayama I1UJW, Omi wOO:, Yoshiki-gun fillitll1\.
mij(gQ)Ttfll15l!R*.i£:~,@M Striatifera :to.t v: Gigantoproductus: dJitJi!-Yj!dillitB15J:3i:t-J
mij(gQ)-Q) ;fr~:ijlTilB U:$ e.' -It -kPt) .t ~ mGht.:: 2 fi Q) ~JiM, Striatifera striata(Fischer de Waldheim, 1837) ,!: Gigantoproductus sp. t;::"?I.,"(~ctt-to.
S. striata ftj;::@Q) ~ / 7' p Y!l !J ;r..fJ/-Q) 1 fi-c-~ ~, ;: h i -C-t;:: l' 9" ~ ;r.. • 7 '7 ;/;r.. •-"'/1.-9"-· r l' '/ • Yj!I!1fSil!ltfll· a:j:rE!!lmtfll· S*Q)J:tflll::.·-It-kPt-Ttfll"t"A -/l.-kPttJ'G.i£:/fltJ'%IGh "(1.'0. hftJ, 1 f71j-C-ft~otJ', J:tfll r 11.-* -kPttJ'I?Q)¥IH1f4>~o.

EBIR*Jti- • bn~

IDJ(

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 142, pp. 400-408, pis. 79-80, June 30,1986

815. SOME PERMIAN CYCLOLOBACEAE FROM THE
SOUTHERN KITAKAMI MASSIF, NORTHEAST JAP AN*
MASAYUKI EHIRO
Department of Earth Science, College of General Education, Tohoku University, Sendai 980

SHOICHI SHIMOYAMA
Department of Geology, Faculty of Science, Kyushu University, Fukuoka 812
and

MASAFUMIMURATA
Department of Geology, Faculty of Science, Kumamoto University, Kumamoto 860

Abstract. Five specimens of the Middle to Upper Permian ammonoids, Stacheoceras otomoi, sp. nov., S. sp. and Timorites intermedium (Wanner) are describedfrom the Ogatsu, Utatsu and Okago districts in the Southern Kitakami Massif.

Stacheoceras sp. from the Okago district occupies the highest stratigraphic horizonof the genus in Japan. Timorites from the Utatsu district is associated with theDzhulfian ammonoids. Thus the genus Timorites ranges upward to the Dzhulfian,in Japan.

In addition to these specimens, some cyclolobacean ammonites, which have been collectedfrom the Permian in the Southern Kitakami(Text-fig. 1) are at hand. The three species described in this paper are as follows:
Stacheoceras otomoi, sp. nov. - from the basal
part of the Toyoma Formation at the northern coast of Obama, Ogatsu district.
Stacheoceras sp. - from the lower part of the
Toyoma Formation at the northwestern coastof Obama, Ogatsu district and from the uppermost part of the Senmatsu Formation, Okago
district.
Timorites intermedium (Wanner) - from the
Oyakejima Formation at Koyakejima, Ogatsu
district and from the lower part of the Suenosaki Formation at Ishihama, Utatsu district.

Introduction and acknowledgments
Permian rocks are widely distributed in theSouthern Kitakami Massif, Northeast Japan,
where they consist of various fossiliferous marine
strata. Although the ammonoid cephalopods
constitute a relatively rare component of thesefaunas, significant specimens for correlation
have been reported from the Middle to Upper
Permian since the first discovery of Stacheoceras from the Iwaizaki Limestone by Mabuti(1935). Recently, rather rich fauna belonging
to 9 genera were described from the Upper
Permian (Ehiro and Bando, 1985).
*Received June 24, 1985; Read June 16, 1985
at Osaka City University.
400

815. Permian Cyclolobaceae from Kitakami

401

Kakuda High School for the permission to study
his specimen.
Stratigraphic note of the ammonite localities

1~4~

Text-fig. 1. Map showing the distributionof the Permian in the southern part of the Southern Kitakami Massif and the fossil localities.
1. Permian, 2. Triassic, 3. Jurassic, 4. Lower
Cretaceous, 5. Cretaceous intrusive rocks, 6.
fossil localities.
Before going further, the writers wish to express their deep gratitude to the late Professor
Yuji Bando of Kagawa University for his valuable
encouragement during the course of the study.
We are also much indebted to Professor Tamio
Kotaka of the Institute of GilOlogy and Paleontology, Faculty of Science, Tohoku University, for his critical reading of the manuscript.
Thanks are expressed to Mr. Tetsuro Otomo of

The Permian in the Southern Kitakami Massif
is divided into the Sakamotozawan, Kanokuran
and Toyoman Series, in ascending order.
In the Ogatsu district, the Permian formations
distribute in relatively limited areas constructing
an anticlinolium plunging southward. They are
unconformably overlain by the Lower Triassic
Hiraiso Formation (Text-fig. 2). The stratigraphyof the Permian was studied by Inai and Takahashi(1940), and recently revised by Murata andShimoyama (1979). The Permian is divided
into the Oyakejima Formation below and the
Toyoma Formation above. The former, thecorrelative of the Kanokura Formation, includes
the Oyakezima (Oyakejima) Sandstone, Koyakezima (Koyakejima) Conglomerate and Sandstone,
and Kohama (Obama) Limestone of Inai and
Takahashi (1940). The latter corresponds to the
Toyoma Slate of Inai and Takahashi (1940).
The Oyakejima Formation consists of sandy
shale, with beds and lenses of conglomerate,in the lower part and limestone and calcareous
sandstone in the upper part. The lower partis mainly exposed in the small islets in theeastern part of Naburi Bay, such as Oyakejima
and Koyakejima. The lithologic sequence of the
Koyakejima section is as follows:
6. conglomerate, cobble to pebble. 15 m+.
5. sandy shale, dark grey. 15 m.
4. granule, lenticular, with crinoid fragments.
0.3m-.
3. sandy shale, dark grey. 8 m.
2. granule, lenticular, with calcareous matrix.
0.4 m.
1. sandy shale, dark grey.15 m+.
Timorites intermedium was collected from theunit 4 of the above mentioned sequence (Loc. 1,
Text-fig. 2).
The upper part of the Oyakejima Formation
is exposed sporadically in the small areas at thenortheastern cape of Naburi, northern coast of
Obama and northwestern coast of Obama. At the402

Masayuki ERlRO, Shoichi SRIMOYAMA and Masafumi MURATA

parts (Murata and Shimoyama, 1979). The lower
part consists of sandy shale interlaminated orinterbedded with sandstone and sometimes contains calcareous nodules. It attains about 500
m in thickness and yields some molluscan fossils,
such as Euphemitopsis kitakamiensis and Astartella toy ome nsis, which characterize the Lower
Toyoman Series (Murata and Shimoyama, 1979).
Stacheoceras otomoi, sp. nov. was collected fromthe basal part of the Toyoma Formation, 0.5 m
above the base, at the northern coast of Obama(Loc. 2, Text-fig. 2) and the present specimen of
Stacheoceras sp. was collected from the upper
part of the lower part at the northwestern coast

I:

7

6

5

Text-fig. 2. Geological map of the Ogatsu
district (modified from Murata and Shimoyama,1979). Locs. 1-3 are ammonite localities.
1-3. Permian (1. Oyakejima Formation, 2. lower
part of the Toyoma Formation, 3. upper part of
the Toyoma Formation), 4-7. Lower-Middle
Triassic (4. Hiraiso Formation, 5. Osawa Formation, 6. Fukkoshi (Kazakoshi) Formation, 7.
Isatomae Formation).
northern coast of Obama it forms an anticline
plunging to the south. On the west flank of the
anticline the upper part of the formation is about
30 m in thickness. Its lower half is composed of
calcareous, fossiliferous sandstone and interbedded with thin (less than 1 m) impure limestone in the middle part. The upper half consistsof pebbly limestone and calcareous sandstone.
Hayasaka (1940) described Stacheoceras sp.
from the limestone of Obama. Lepidolina kumaensis and L. multiseptata were also reported
from the uppermost part of the formation(Murata and Shimoyama, 1979).
The Toyoma Formation, conformably overlies
the Oyakejima Formation, is divided into twoof Obama (Loc. 3).
The upper part of the Toyoma Formation iscomposed of rather massive black shale withcalcareous nodules, and attains 300 m in thickness. Palaeoneilo ogachiensis, Nuculites kimurai,
Protocycloceras cf. P. cyclophorum, etc. werereported from this horizon (Hayasaka, 1924).
The first two characterize the Middle Toyoman.
The stratigraphy and the ammonite fauna of
the Utatsu and Okago districts are already reported by Ehiro and Bando (1985). In the
Utatsu district the Permian is divided into the
Suenosaki Formation (Uppermost Kanokuran to
Lower-Middle Toyoman) and the Tonoura Formation (Upper Toyoman). The lower part of
the Suenosaki Formation (Lowermost Toyoman)yields some ammonite fossils, such as Stacheoceras iwaizakiense, Pseudogastrioceras sp., Araxoceras cf. A. rotoides and Prototoceras japonicum,in association with Euphemitopsis kitakamiensis
and Astartella toyomensis, at the eastern coastof Ishihama. The present specimen of Timorites
intermedium was collected from the same locality of ishihama, loco 3 of Ehiro and Bando(1985, fig. 2).
The Middle to Upper Permian in the Okago
district is divided into the Higashifukakaya,
Shinden, Okago and Senmatsu Formations inascending order. The Okago and Senmatsu Formations are correlated to the Lower-Middle
Toyoman and Upper Toyoman, respectively(Ehiro and Bando, 1985). Xenodiscus cf. X.
carbonarius was reported from the lowermost

815. Permian Cyclolobaceae from Kitakami

part of the Okago Formation. The Senmatsu
Formation yields the following ammonoids:
Cyclolobus cf. C. walkeri, Medlicottia kitakamiensis, Eumedlicottia sp. and Paratirolites? sp.
The present specimen of Stacheoceras sp. wascollected from the uppermost part of the Senmatsu Formation near Nagasakiyama (loc. 16
in fig. 4; Ehiro and Bando, 1985), associated with
Medlicottia kitakamiensis.
Faunal consideraiton
Of the present ammonoids, Stacheoceras is
one of the common element in the Permianstrata in the Tethyan Province and North America. Some specimens have also been known from
the Middle to Upper Permian in Japan, especiallyin the Southern Kitakami Massif. Stacheoceras
iwaizakiense was first described by Mabuti (1935)
from the lower part of the Iwaizaki Limestone,
Monodiexodina matsubaishi zone, in the South·
ern Kitakami and additional specimens wererecently reported from the Dzhulfian bed ofUtatsu (Ehiro and Bando, 1985). Stacheoceras
sp. was described by Hayasaka (1940) from theupper part of the Oyakejima Formation at
Obama. Other species previously known from theSouthern Kitakami, though not described, are
Stacheoceras cf. S. trimurti from the lower partof the Toyoma Formation at Toyoma (Working
Group, 1975), S. sp. from the Kanokura Formation at Tagara, Kesennuma City (Akiyama, 1958;
Hayasaka, 1960) and S. sp. from the upper partof the Iwaizaki Limestone at Iwaizaki (Koizumi,1967).
In addition to these Kitakami specimens,
Stacheoceras aff. S. grilnwaldti from the Kanokuran Kashiwadaira Formation of the Abukuma
Massif, Northeast Japan (Hayasaka, 1965) andS.? sp. from the Akasaka Limestone, corresponds to the Kanokura Formation, in Central
Japan (Hayasaka, 1955) have been known fromJapan. The stratigraphic horizon of above mentioned Stacheoceras is from Kungurian to Lowermost Dzhulfian.
Stacheoceras otomoi, sp. nov. from Obama
was collected from the basal part of the Toyoma

403

Formation and the horizon is nearly the same asthat of S. iwaizakiense from Utatsu. Ogatsu
specimen of Stacheoceras sp. was collected fromthe upper part of the lower part of the Toyoma
Formation, slightly higher horizon than that ofS. otomoi and is of Late Early Dzhulfian. The
Okago specimen of Stacheoceras sp. was collected from the uppermost part of the Senmatsu Formation. This formation is correlated
to the Dorashamian (Ehiro and Bando, 1985).
Therefore, the present specimens of Stacheoceras sp. occupy the higher stratigraphic horizon
than those of the specimens of the genusStacheoceras previously reported from Japan and thatof the Okago specimen is the highest.
Timorites intermedium is of great importance,
because the species of Timorites are index fossilsof the zone of Timorites (Miller and Furnish,1940) or of the Capitanian and Amarassian of
Furnish (1973). T. intermedium was first described from Timor as Waagenoceras intermedium by Wanner (1932) and later found from the
Kanokura Formation in the Southern Kitakami,
Japan (Hayasaka, 1954). Other species of Timorites have been reported from the Amarassi Bed
in Timor, including the type species, T. curvicostatus (Haniel, 1915; Smith, 1927), from the
Capitan ian in North America (Miller and Furnish,
1940; Miller, 1944), from Far East of USSR
(Ruzhentsev, 1955) and from the Maokouan
in South China (Liang, 1983) and Tibet (Sheng,1984). Amarassian of Furnish (1973) is now considered to be equivalent to the Abadehian(Iranian-Japanese Research Group, 1981).
The Ogatsu specimen of Timorites was collected from the lower part of the Kanokuran
Oyakejima Formation and the horizon is probably correlated to the Capitanian, because thehorizon is slightly lower than that of Lepidolina
kumaensis which is correlated to the Abadehian(Ehiro and Bando, 1985). On the other hand,thl.' Utatsu specimen was found in association
with typical Dzhulfian ammonoids, such as
Araxoceras cf. A. rotoides and Prototoceras
japonicum. Therefore, in Japan, the stratigraphic
range of the genus Timorites is considered torange up to the Dzhulfian, at least to its lower

404

Masayuki EHIRO, Shoichi SHIMOYAMA and Masafumi MURATA

part.
Systematic description
Superfamily Cyclolobaceae Zittel, 1895
Family Vidrioceratidae Plummer and Scott, 1937
Genus Stacheoceras Gemmellaro, 1887
Type species:-Stacheoceras mediterraneum
Gemmellaro, 1887.
Stacheoceras otomoi, sp. nov.

PI. 79, Figs. 1a-d; Text·fig. 3A.
Material:-One specimen, a phragmocone, ahalf of the last whorl is missing, collected by T.
Otomo in 1957 from the basal part of the
Toyoma Formation at Obama, Ogatsu-cho,Monoo-gun, Miyagi Prefecture. IGPS coIl. cat.
no. 98895.
Description:-The conch is involute, subglobular to subdiscoidal, with closed umbilicus,
rounded-convex sides and broadly rounded venter. The phragmocone attains a diameter of atleast 40 mm, and at the adoral end the height is
24 mm and the umbilical diameter is about 3
mm. The width is estimated at about 19 mmfrom half part of it. But, the material is slightly
deformed obliquely and the original width ismore wider, may be 22 mm or so. Shell ornamentation is unknown, but the surface of theinner mould is smooth. Suture is well preserved
as shown in Text-fig. 3A and consists of ventral
lobe and nine lateral lobes. The ventral lobe isbroad and bifid. The first lateral lobe is primarily
bifid, but secondary quadrifid. The second to fifth
lateral lobes are trifid and all diminish in sizeand complexity toward umbilicus. Subsequentlobes are rounded but those nearest the umbilicus sometimes slightly bifid.
Remarks:-The present new species is characterized by its slightly compressed shell form
and the shape of the suture, particularly by thequadrifid first lateral lobe and simpler laterallobes near umbilicus.
The present species resembles Stacheoceras
iwaizakiense Mabuti (Mabuti, 1935, p. 147, pI.

14, figs. 1-7), which also occurs from Permianin the Kitakami, in the shell form, but easily
distinguished from the latter by its large number of lateral lobes. Regarding the suture line,
especially the form of the first lateral lobe, thenumber of lateral lobes, and the shell outline,
the present species is closely related to Stacheoceras trimurti Diener (Diener, 1897, p. 9, pI. 1,
figs. 1a-e) from the Chitichum Limestone ofCentral Himalayas, S. tridens (Rothpletz) (Rothpletz, 1892, p. 87, pI. 9, figs. 4, 4a-b; Haniel,
1915, p. 105, text-fig. 35; Smith, 1927, p. 50,
pI. 13, figs. 18-21) from Timor, S. gordoni
Miller, Furnish and Clark (Miller et al., 1957,
p. 1062, text-fig. 3, pI. 134, figs. 1-4) from
California and other allied species. But theOgatsu species differs from the Himalayan,
Timorian and Californian species in simpler
form of lateral lobes near umbilicus.
Stacheoceras sp.

PI. 79, Figs. 2a-b, 3; Text-figs. 3B, 3C.
Material:-Two fragmental specimens, collected by S. Shimoyama in 1972 from the lower
part of the Toyoma Formation at the northwestern coast of Obama, Ogatsu-cho, Monoogun, Miyagi Prefecture, IGPS coIl. cat. no. 98896
and collected by M. Ehiro in 1983 from the+If!l~·r
~~

-+J
J

1 em

Text-fig. 3.

Suture lines of Stacheoceras.

A. Stacheoceras otomoi, sp. nov., rGPS coIl. cat.

no. 98895. B. S. sp., rGPS colI. cat. no. 98896.
C. S. sp., rGPS coIl. cat. no. 988g9.

815. Permian Cyclolobaceae from Kitakami
uppermost part of the Senmatsu Formation near
Nagasakiyama, Senmatsu, Fujisawa-cho, Higashiiwai-gun, Iwate Prefecture, IGPS colI. cat. no.
98899.
Remarks:-The specimens at hand are fragmental and deformed, but in both specimens apart of the suture is preserved as shown in TextFig. 3B-C. They have characteristic forms of
Stacheoceras and consist of entire lateral saddles
and trifid lateral lobes, all diminish in size gradually toward umbilicus. The Ogatsu specimen
has a closed umbilicus. The outer whorls of it,
in appearance, have acutely arched venter, but
it is due to deformation.
Family Cyclolobidae Zittel, 1895
Genus Timorites Haniel, 1915
Type species:-Timorites curvicostatus Haniel,
1915.
Timorites intermedium (Wanner, 1932)
PI. 79, Figs. 4a-b; PI. 80, Figs. 1a-d;
Text-figs.4A-4B.
1932. Waagenoceras intermedium Wanner, p.

272, text-figs. 1a-b, pI. 9, fig. 1, pI. 10,
fig. 1.
1933. Hanielocerasintermedium (Wanner),
Miller, p. 413.
1940. Timorites intermedium (Wanner), Miller
and Furnish, p. 173.
1944. Timorites intermedius (Wanner), Miller,
p. 114, pI. 43, figs. A-C.
1957. Timorites curvicostatus Haniel, Miller etal., L. 50, figs. 66A-C.
1975. Timorites curvicostatus (Haniel), Koizumi, pI. 16, figs. 3a-b.
?1954. Hanieloceras intermedium (Wanner),
Hayasaka, p. 368, pI. 23, figs. 4a-c.
?1975. Timorites intermedium (Waagen), Koizumi, p. 72, pI. 16, figs. la-b.
Material:-Two deformed and partly squashedspecimens, collected by S. Shimoyama in 1972
from the lower part of the Oyakejima Formation
at Koyakejima, Ogatsu-cho, Monoo-gun, Miyagi
Prefecture, IGPS coli. cat. no. 98897 and collected by M. Ehiro in 1983 from the lower part405

of the Suenosaki Formation at the eastern coastof Ishihama, Utatsu-cho, Motoyoshi-gun, Miyagi
Prefecture, IGPS coli. cat. no. 98898.
Description:-The conch is fairly large forTimorites, measuring about 250 mm in diameterat the end of the phragmocone for the Ogatsu
specimen, though it is nearly parallel to thelongest axis of the elliptically deformed. Corresponding height, width and umbilical diameterare about 110, 77 and 52 mm, respectively. The
Utatsu specimen measures more than 300 mm indiameter.
The conch is involute, with a narrow umbilicus, about 20 percent of the conch diameter.
Outer whorl embraces completely inner whorls.
In the Ogatsu specimen, venter is narrowly
rounded, sides are flattened and grade round into
venter. Umbilical wall is almost perpendicular.
Faint radial swellings are recognized along theumbilical edge. The shell is thin, less than 2 mmin the Ogatsu specimen and not quite 1 mm in
the Utatsu specimen, with weakly sigmoidal,
fine, simple transverse ribs on the phragmocone,
but it seems to be smooth, as seen in the Ogatsu
specimen, on the body-chamber.
The sutures are rather well preserved as shownin Text-fig. 4. It is convex anteriorly. There areat least seven, probably eight or nine outer lobes
between the ventral lobe and the umbilicalshoulder. The ventral lobe is the largest, widest
and deepest, but narrowed anteriorly, divided
into two part by a median saddle, about 2/3
height of the ventral lobe. External and lateralsaddles, with mushroom-shaped apexes, are digitate along their flanks and lateral lobes are also
digitate. External saddles are convex toward umbilicus, whereas axes of all other saddles arepractically straight. Lateral saddles and lobes
diminish gradually in size toward umbilicus.
Remarks:-The present specimens are clearly
identified with Timorites intermedium (Wanner)in the large size, compressed shell form, theornamentation of shell surface and the characteristic features of septa.
The holotype of Timorites intermedium wasoriginally described by Wanner (1932) as Waagenoceras intermedium from the Basleo Bed of

406

Masayuki EHIRO, Shoichi SHIMOYAMA and Masafumi MURATA
References

Scm

Text-fig. 4. Suture lines of Timorites intermedium (Wanner).
A. lOPS colI. cat. no. 98897. B. IGPS colI. cat.
no. 98898.
Timor. The second specimen was found from the
Kanokura Formation in the Southern Kitakami,
Japan (Hayasaka, 1954). However, it should
seem to be difficult to identify the specific level.
Assignment of Hayasaka's specimen to T. intermedium made on the basis of outward appearance of shell form and complexity of suture, istentative, because it is a fragmental, deformed
inner mould and detailed shell form and ornamentation of shell surface are unknown.

Akiyama, T. (1958): On the fossil cephalopods
from the Permian Kanokuran Series. Chigaku Kenkyu (Jour. Soc. Earthsci. Amateurs
Japan), vol. 10, p. 119-121 (in Japanese).
Diener, C. (1897): The Permocarboniferous
fauna of Chitichum, No. I. India Geol. Suru.
Mem., Palaeont. Indica, Ser. 15, vol. 1, pt. 3,
p.1-105.
Ehiro, M. and Bando, Y. (1985): Late Permianammonoids from the Southern Kitakami
Massif, Northeast Japan. Trans. Proc. Palaeonto Soc. Japan, N.S., no. 137, p. 25-49.
Furnish, W. M. (1973): Permian stage names.
In Logan, A. and Hills, L. V. (eds.), The
Permian and Triassic Systems and theirmutual boundary. Mem. Canad. Soc. Petrol.
Geol., no. 2, p. 522-548.
Haniel, C. A. (1915): Die Cephalopoden derDyas von Timor. Paliiont. von Timor, Lief.
3, Abh. 6, p. 1-153.
Hayasaka, I. (1924): Fossils in the roofing slateof Ogachi, Provo Rikuzen. Japan. Jour. Geol.
Geogr., vol. 3, p. 45-53.
--(1940): On two Permian ammonoids fromthe Kitakami Mountains, north Japan. Jour.
Geol. Soc. Japan, vol. 47, p. 422-427.
- - (1954): Younger Palaeozoic cephalopods
from the Kitakami Mountains, Japan. Jour.
Fac. Sci., Hokkaido Univ., Ser. 4, vol. 8, p.
361-374.
--(1955): On the Permian cephalopods inJapan. Chigaku Kenkyu (Jour. Soc. Earthsci. Amateurs Japan), vol. 8, p. 71-76 (inJapanese).
- - (1960): A new Permian species of Foordi-

Explanation of Plate 79
Figs. 1a-d.· Stacheoceras otomoi, sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pa:ge 404
IGPS colI. cat. no. 98895, lateral (a, c), back (b) and front (d) views, x 1.2.
Figs. 2a-b. Stacheoceras sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 404
IGPS colI. cat. no. 98896, lateral (a) and front (b) views, x 0.7.
Figs. 3. Stacheoceras sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 404
IGPS colI. cat. no. 98899, lateral view, x 1.5.
Figs. 4a-b. Timorites intermedium (Wanner) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 405
IGPS colI. cat. no. 98898, lateral view (a), x 0.25 and lateral view of inner whorl(b), x 0.45.
All specimens illustrated here are preserved in the Institute of Geology and Paleontology,
Faculty of Science, Tohoku University, Sendai.

EHIRO et al: Permian Cyclolobaceae from Kitakami

Plate 79

815. Permian Cyclolobaceae from Kitakami
ceras from the Kitakami Mountains. Bull.
Nat. Sci. Mus., vol. 5, p. 86-94.
--(1965): Some cephalopods in the Permian
faunule of Takakura-yama, Fukushima Prefecture, Japan (with a note on the geologyof the district, by Ichiro Yanagisawa andMamoru Nemoto). Trans. Proc., Palaeont.
Soc. Japan, N.S., no. 57, p. 8-27.
Inai, Y. and Takahashi, T. (1940): On the geology of the southern part of the Kitakami
Massif. Contr. Inst. Geol. Palaeont., Tohoku
Univ., no. 34, p. 1-40 (in Japanese).
Iranian-Japanese Research Group (1981): The
Permian and the Lower Triassic Systems in
Abadeh Region, Central Iran. Mem. Fac. Sci.,
Kyoto Un iv. , Ser. Geol. Mineral., vol. 47, p.
61-133.
Koizumi, H. (1967): On the Palaeozoic Permiancephalopods from Japan, Pt. 1. Chigaku
Kenkyu (Jour. Soc. Earthsci. Amateurs
Japan), vol. 18, p. 130-135 (in Japanese).
--(1975): Palaeozoic cephalopods of Japan.
149 p. Teiseki Bunko, Chiba (in Japanese).
Liang, X. (1983): New material of Permian ammonoids with discussion on the origin, migration of Araxoceratidae and the horizonof the Para tiro lites. Acta Palaeont. Sinica,
vol. 22, p. 606-615 (in Chinese with English
abstract).
Mabuti, S. (1935): On the occurrence of Stach eoceras in the Kitakami Mountainland, Northeast Honshu, Japan. Saito Ho-on Kai Mus.,
Res. Bull., no. 6, p. 143-149.
Miller, A. K. (1933): Age of the Permian limestones of Sicily. Amer. Jour. Sci., 5 Ser.,vol. 26, p. 409-427.
(1944): Part IV. Permian cephalopods. In
King, R. E., Dunber, C. 0., Cloud, P. E. Jr.
and Miller, A. K., Geology and palaeontology of the Permian area northwest of Las
Deliceous, southwestern Coahuila, Mexico.
Geol. Soc. Amer., Spec. Pap., no. 52, p. 71127.
- - and Furnish, W. M. (1940): Permian am-407

monoids of the Guadalupe Mountain Region
and adjacent areas. Ibid., no. 26, p. 1-242.
- , - - and Clark, D. L. (1957): Permianammonoids from Western United States.
Jour. Paleont., vol. 31, p. 1057-1068.
- - , - - and Schindewolf, O. H. (1957):
Palaeozoic Ammonoidea. In Moore, R. C.
(ed.), Treatise on invertebrate paleontology,
Pt. L. Mollusca, 4. Ammonoidea, L. 11-79.
Geol. Soc. America and Kansas Univ. Press.
Murata, M. and Shimoyama, S. (1979): Stratigraphy near the Permian-Triassic boundary
and the Pre-Triassic unconformity in the
Kitakami Massif, Northeast Japan. Kumamoto Jour. Sci., Geol., vol. 11, p. 11-31(in Japanese with English abstract).
Rothpletz, A. (1892): Die Perm-, Trias- und JuraFormation auf Timor und Rotti im indischen
Archipel. Palaeontographica, Bd. 39, p. 57106.
Ruzhentsev, V. E. (1955): The Family Cyclolobidae Zittel. Acad, Sci., USSR, Doklady,
vol. 103, p. 701-703 (in Russian).
Sheng, H. (1984): Late Lower Permian ammonoids from Xiukang Formation, Lhaze
District, Xizang (Tibet). In Zhou, W. andWang, S. (eds.), Himalayan Geology II.
Part of achievements in geoscientific investigation of Sino-French cooperation in the
Himalayas in 1981, p. 219-243. Geol.
Publ. House, Beijing (in Chinese with English
abstract).
Smith, J. P. (1927): Permian ammonoids ofTimor. Mijnw. Nederlandsch-Indie· Jaarb.,
Jaarg. 55, Verh. 1, p. 1-58.
Wanner, J. (1932): Beitrage zur Palaontlogie desOstindischen Archipels, III. Zur Kenntnis
der permischen Ammonoideen-fauna vonTimor. N. Jahrb. Min. Geol. Paliiont., Beil.Bd. 67, p. 257-278.
Working Group on the Permian-Triassic Systems(1975): Stratigraphy near the Permian-Triassic boundary in Japan and its correlation.
Jour. Geol. Soc. Japan, vol. 81, p. 165-184(in Japanese with English abstract).

Masayuki EHIRO, Shoichi SHIMOYAMA and Masafumi MURATA

408

Abukuma ~j\Ill. Akasaka w-t&, Fujisawa-cho IitRlIIJ, Fukkoshi (Kazakoshi) .m.~. Higashifukakaya *~E:. Higashiiwai-gun *~:ttr.~. Hiraiso :i(Z~. Isatomae fJt.fIl.wI. Ishihama ;p~. Iwaizaki:ti:ttrot. Kanokura Ilt:t. Kashiwadaira -l'E:i(Z, Kesennuma ~flll ilL Kitakami ~tJ::. Koyakejima Ij'/\Jl!:!Ei. Monoo-gun tlt1;.W. Motoyoshi-gun *ilflll5. Naburi ~~. Nagasakiyama ~*'fU-l. ObamaIj,~. Ogatsu (-cho) tilJ1 (IIIJ). Okago j;:H. Osawa j;:tR. Oyakejima j;:J\:l!l-~. Sakamotozawa t&
Senmatsu TtL Shinden firm. Suenosaki *Q)rot. Tagara mm. Tanoura mQ)iIli. Toyoma~*. Utatsu(-cho) llJXf.f:(IIIJ)*tR.

wH!Il~tJ::U-l~jft~/L-A*C-lj---(!lP p'~7-J::f47:N::r--( r: wnm~tJ::U-l~Q)&lJm.

ilf,I:j$.t.;.1 V'j;:~~lli1(Q)<p • J::f:il~/L- A*jft7 '/ -"E;:r --( r 31ll! Stacheoceras otomoi. sp. nov .• S. sp .
.t.; .1 V' Timorites intermedjum (Wanner) ~ft~~~ Lt.:: 0 j;:lmjftQ) Stacheoceras sp. It.:
"i--CI3*iJ'l?mi!f~nt.:: Stacheoceras Q)<P--CAi4>J::f:iIQ)II*~liclbG. i!fkifjftQ) Timorites
intennedium 11;;(11-- 7 7 - JtIl7 '/ -'f::r --( Ht;p c ;tI<il-r G Q)"('. 13 *t.::..t.;1-t G Timorites ~nQ)v ,/7'11;;( 11--77 -jmr.::."i --C}!!;~~nG.

7l<Itl§z • TU-llE- • NmlEX

Explanation of Plate 80
Figs. la-d. Timorites intermedium (Wanner) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 405
IGPS colI. cat. no. 98897, lateral (a, c) and ventral (b, d) views, x 0.4.
Specimen illustrated here is preserved in the Institute of Geology and Paleontology, Facultyof Science, Tohoku University, Sendai.

EHIRO et al: Permian Cyclolobaceae from Kitakami

Plate 80

HI[

r#J
19871f.

1f.~. ij'(€.~

~

IlUl

r#J

:I!B

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Transactions and Proceedings of the PalaeontologicalSociety of Japan
June 30, 1986

New Series No. 142

CONTENTS
TRANSACTIONS
811. HORIUCHI, Junji and KIMURA, Tatsuaki: Ginkgo tzagajanica Samylina from the
Palaeogene Noda Group, Northeast Japan, with special reference to its external
morphology and cuticular features • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
812. NODA, Masayuki: A new species of Inoceramus (Cordiceramus) (Bivalvia) from theUpper Coniacian (Cretaceous) of Hokkaido . . . . . . . . . . . . . . . . . . . . . . . . 354,
813. TASHIRO, Masayuki and MATSUDA, Tomoko: Lower Cretaceous bivalves from the
Sakawa area, Shikoku . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
814. TAZAWA, Jun-ichi and KATO, Makoto: Striatifera and Gigantoproductus from theLower Carboniferous of Fukuji, Central Japan . . . . . . . . . . . . . . . . . . . . . . 393
815. EHIRO, Masayuki, SHIMOYAMA, Shoichi and MURATA, Masafumi: Some Permian
CyclolobaceaeJrom the Southern KitakamiMassif, Northeast Japan ....... 400