a -lt"'~±~~~{U..~· !c..f
Transactions and Proceedingsof thePalaeontological Society of Japan
New Series

No. 6-lPalaeontological Society of japan
June 15, 1959

CONTENTS,
TRANSACTIONS
Page359. Taxodonta and Isodonta from the Upper Jurassic Sakamoto Formationin Central Kyushu, Japan .............................. J\Iinoru TAMURA 53
360. Pelecypods of the :~vlizunuma Jurassic in Miyagi Prefecture, with some
Stratigraphical Remarks. (Studies on the Liassic Pelecypods in Japan, 10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Itaru HAY AMI

66

361. :Kotes on Some Permian Corals from Fukuji, Hida Massif. Central Japan .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hisayosh leo 79362. On the l\Hocene Pectinidae from the Environs of Sendai : Part 14, On
Pecten swiftii BERNARDI ................................ Koichiro MAsuDA 86
363. T1·igonioides and its Classification (Studies on the Molluscan Fauna of theCretaceous Inkstone series. Part 2) ...................... Yoshihisa 0TA 97
364. On the "Nippo11o11aia" from the Lower Cretaceous Wakino subgroup,
North Kyusyu, Japan. (Studies on the l\1olluscan Fauna of the Cretaceous
Inkstone series, Part 3) .................................. Yoshihisa 0TA 105

SHORT NOTES
3.
•1.

An Additional Note on the Liassic 'Cyrenoids ·• in Japan ... Itaru IIAYAMI 78
Triticiles tlzalmamzi SAKAGAMI and 0:-..IATA and Sclumgeri11a guembeli omensis
SAI<AGA~ll and 0:..1ATA, ne\v name for T. lntermedia and S. guembeli
compacta ....................... . Sumio SAI<AGAMI and Toshikazu 01\IATA 111

President: Teiichi KoBAYAsHI
Councillors: Kiyoshi AsANo, Riuji ENvo (Publication), Seido ENDO. Haruyoshi FunMOTO (Treasurer), Shoshiro HANzAwA, Kotora HATAI, Ichiro HAYASAKA, Kazuo
Huzioi<A, Nobuo IKEBE, Jiro l\Lo.KIYAMA. Tatsuro MATsuMoTO, Masao MINATo,
Tokio SmKAMA (General Affairs), Fuyuji TAKAI (Editor), Ryuzo ToRIYAMA
Secretary: Tetsuro HANAI
Assistant Secretary: Takeo IcHIKAWA

All Communications relating to this Journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, University of Tokyo, Japan

Trans. Proc. Palaeont. Soc. Japan. N. S., No. 34, pp. 53 .. ()5, pl. 6. June 15, 1959

359.

TAXODONTA AND ISODO.NTA FRO.M THE UPPER JURASSICSAKAMOTO FORMATION I::-r CE.L\TRAL KYUSHU. JAPAN*
MINORU TAMCRA
Faculty of Education. Kumamoto UniYersity

J:ifl~:;.:t.=.;;~Hii*Jgjim0 Taxodonta &0' Isodonta: tm4:t'T!ffi~r:f.)-ftii'7.> l:;·~;:;.:t.
7 ~.!&*1(•.1 J: IJ im'i '!> Taxodonta 6 f.ll, Isodonta 16 !<R. .!I' ~~ fill (-) ; 5 flfHD ~ Jcil\X'Lf:,Calella (Torinosucalella) kobayashii. new subgen. and new sp. '!_> {, t I., "C.
Cale/la IIEALEY (l');:f:tl: Torinosucalella !!l!'lll'!.>lfr;fi:L.-t:, Z't¥0=&a;~~'mnl~ftll::r;u'itt t1. 7.> !, cJ)fPkA U.;t 't;:. ~I.-f.: t VC I'Y~0~1ll~.itl!0no)t.n/mll't~0 t. 01::f,'Jib!>"C1JHJ;J.
L,"(l.l;jo
fll
N
J?:.

x

In the second part of this study the
Taxodonta and Isodonta arc described.
The horizons and localities of the fossils
have already been listed in the previous
paper I,TAw IL\, 1959). T. KP.. It'HA has
described many pelecypods of thesegroups, especiallv Pectinaceac, from theljpper Jurassic Torinosu group in Sakawa basin lKl~IURA, 19!11 & 1956). HereCate!la Ih:AI.EY (1908) is promoted to thegeneric rank and Torinosucatella, subgen.
nov. is erected on Cat ella (Torinosucatella)kobayashii. new species. Remarks are
given on Somapecten ·which is very akin
to Ento/ium and has a peculiar strong
angular conical tooth in the right valve
and a corresponding socket in the othervalve. The species here described are
as follows:
Parallelodon i11.flatus TA:'Ifl'R,\. new species
Grammalodon takiensis KJ:\IUHA
Catella ( Torinosucatel!a) kobayashii TA ~IU­
RA. new subgenus and new species
Nuculana ( Praesaccella) erinoensis K 1\1 c RA
:Vuculana ( l'raesaccella) yatsushir01:nsis TA:'IIURA. new speciesl•luculana (!Jacryomya) stenodolichos KJ:\IL'RA
Clilamys (Chlamys) iboibo KuRATA and
KI\Il'R.\*Received Aug. 30. 1958: read S..:pl. 27,
1958.

c

Chlamys (Cit!mnys) sp.
Chlamys (Radu!opedcn) ogawensis KIMURA
Chlamys ( Radulopecten) nagatallensis KUHATA and KI\Jl'R.'\"Aequipeclen" mlgaris Kr:'l!l'I~A"Aequipeclen" kotsubu (Kl\ll'RA)
Camptonecfes sp. aff. brotnti C• >X
Camptonecfcs ? sp.
EoPecten sp.
Varimmtssium !Jabtmokau.·eltse ( K1 \IURA)
Entolium yrtfsujiense Kt:RAT,\ and KnwRA
Enlo/ium kimurai TA\ICRA. new species
Sot~wpecten kaminumensis Kr\ll'RA
Lima (P/agioslrmza) sp.
Lima (Ctenoides) tosana Knll.'IL\
Lima/uta rdiculata TA\JUR,\. new species

The writer records his sincere thanks
to Prof. T. 1\nnAYAsrtl of Lhc Universityof Tokyo for his kind guidance andsupervision of the manuscript. Thanks
are also clue to Assist. Prof. T. Knn:R.\
and !\'lr. I. HAL\\rr of the saJlle University for assistances in laboratory works.
Family Parallclodontidae
Genus Parallelodon :\h:E~~: and\V ORTIIE:O..:, 1866

Para/lelodon injlatus T,\:...lt:RA,
ne\v species!'late ti Figures. 9, 10.

54Minoru T1LlfURA

Description :-Shell medium sized forgenus, elongated and oblong in outline.
with length nearly equal to twice theheight, strongly inflated; umbo at about
1/3 or a little less from the anterior
end, improminent. prosogyrate and incurved; sinus invisible on ventral side;
carina-like angulation passing fromumbo to postero-ventral corner; t"·olong posterior teeth nearly parallel toventral margin: hinge of Paral/elodon:
4 posterior and 6 anterior teeth all shortin left valve: surface probably smooth
except for growth-lines.
This species is based on very inflated
internal moulds of right valves whichhave no ventral sulcation.
J11easurement s :holotype

L
43mm
37mm

II
19mm
20mm

Occurrence :-Locs. l 6.

Family Cucullaeidae FJ:-:L.·\Y and~L\RWICK, 193/, emend.
NICOL,

1954

Genus Grammatodon J\IEEK and
lhYDE:-:, 1860

Grammatodon takiensis K1 ~JL:RA!'I ale 6, Figures 1, ~.
1956. Gramma/odon takiensis. KI:o-.Jl'R,\, p. 85.
pl. 1. fig. 6.

Shell small to medium, strongly in11ated, subrectangular in outline, length
to height about 3: 2: posterior marginlonger than anterior: umbo at a thirdor more of the length from anterior, alittle prosogyrate and incurved; fairly
distinct carina running from umbo topostero-ventral margin, but an anterior
one weak; surface covered by fine concentric lamellae but obscure on lateralsides; posterior side depressed and ornamented with about 13 radial ribs;
anterior area with about 6 radial ribs;
very fine radial ribs present in medianpart but generally obscure; hinge typi·
cal of Grammatodon.
Occurrence :-Many specimens of internal and external moulds of both valvesoccur at Locs. 1, 2, 4, 5. 6, 7, 9, 11. 12,
some being deformed.
Genus Catella HEALEY, 1908
Type-species :-Grammatodon (Catella)!at iriaN/ HEALEY.
Generic diagnosis :-Shell equivalve,inequilateral, inflated. trapeziform inoutline and a little produced posterior;umbo slightly prosogyrate, situating alittle anterior to center; surface ornamented with concentric lamellae orradial ribs; a strong internal ridge
passing from umbo towards ventral
margin nearly perpendicular to hinge
margin; the corresponding external constriction present: hinge structure ofGrammatodo1l type.
Remarks :-Subgenus
Catellawaseret:ted by HEALEY (1908) on Grammatodon:Catella) laticlm•a HEALEY from the
Rhaetic Napeng beds of Burma, which
has a strong internal rigde and a corresponding fairly wide constriction insurface passing from the umbo toward
the ventral margin. She included thissubgenus in Grammatodon MEEK and
1-L\\'uE:-:, although the concentric lines
in laticlaoa are almost invisible in Gram·
matodon.
Several specimens with an external
constriction and an internal ridge werecollected from the Upper Jurassic Sakamoto formation. In hinge structure it
agrees with Grammatodon inclusive ofLatella. In these specimens, however,radial ribs are closely spaced and some

359.

Taxodonta and Isodonta from the Upper jurassic

concentric wrinkles weaker than theradial ribs and obscure in some forms.
G. TRowsso" (1951) described Grammatodon (Cate/la) siuuatus and G. (C.)
subrlwmboidalis from the Katslosa bedof Hoganiis Series of Sweden whose age
is uppermost Sinemurian or its transition to Pliensbachian. The former isornamented with radial ribs and con·centric wrinkles as the Sakamoto form.
On the other hand, the latter has thesame external ornaments as G. (C.) laticlava HEALEY. The internal ridge andthe external constriction of Cate/la areevidently different from the ventral
sinus of Paml!elodon or Barbatia in
which the sinus forms a byssal gape.
Emphasizing primarily the internalridge and the corresponding external
constriction and secondarily the external ornaments, the writer promotes
Catel/a HEALEY to the generic rank.
Torinosucatella is erected as its subgenus
which is represented by C. (T.) lwbayaslzii
from Sakamoto formation and includes
G. (C.l sinuatus TRnEossoN (1951).
Subgenus Torinosucate/la T A:<-.!l"RA,
new subgenus.
Type-species :-Catella (Torinosucatel/a)kobayashii T.·\:\tt:RA, new species.
Diagnosis :-·Catetla with radial ribs
and concentric wrinkles on surface;posterior end protruded and generally
auriculate; hinge of Grammatodon type.

I
B

c

D

J[

E

m
.

.

Tcxt·Figure 1. Catella (Catel!a) laticlat·a liEM.EY (II) and Catella( Torinosucatella) kobayashii TA~tt:RA. new sp. (I) :suriacc (A.), internal mould (B), umbonal part (C). hinge area (D).
en largcd constriction (E).

Cate!la ( Torinosucatellal kobayashii
TA:-.tt.:RA, new species
Plate ti. Figures 11-16.

Description :-Shell small. inequi lateral.
well inflated, trapeziform in out line;
umbo at about 1/3 across from anterior
end. slightly prosogyrate and incurved;
hinge line longest, straight and auriculate posteriorly; posterior margin alittle sulcated; postero-ventral cornerproduced: median constnctwn deep.
broadened and becomes shallow near
venter; anterior area smaller than posterior: constriction a little strengthened
internally; ventral margin fairly deeply sulcated at the median part: carinalike ridge round-topped. passing fromumbo to postero-vcntral margin; postcarina! area depressed: surface ornamented with dense radial ribs andseveral concentric wrinkles on \'Cntral
side; hinge of Grammatodon type.
J\Ieasureme11tS :-5()l.l.1i1Wl'zt TAMURII
L
holotype

1:l mm

12
10

H
Gmm
6
4

Comparison:- The ventral sinus is
deep but the gape, if present, is narrow.
The posterior auricle and long hinge
margin are also distinct specific characters. Externally. this is similar to alate
Para!lelodon as typified by P. rugvsum(AREELL, 1930-1). The median sinuation
is absent in the alate group.
G. (C.) sinuatus Ttwt·:ussor-; somewhat
resembles this in ornaments but bascoarse ribs. The posterior dorsal endof sinuatus is probably not so distinctlyalate as in kobayashii. Macrodon sp.
(FtEBELKOR:x. ?vi.. 1893) in north German
boulder derived from the Upper Juras·
sic formation has a fairly deep sinus asin this species but its sinus is not so
deep as in this species. The sandstoneof Infra-Lias of Hettange, Vic-de-Chas·senay and Halberstadt yields Area jmlla
TERQ. which has a distinct constrictionin the middle part ancl rae! ia I and con·centric ribs on the shell. The hinge of
A. pu!la, however, is not of Grammatodo11
type.
Occurence :- Locs. 6. 11.

about twice the height: umbo nearly
orthogyrate. situated a little anteriorly;
antero-clorsal margin a little shorter
than posterior, both margins nearlystraight and forming 140°-150° apicalangle at umbo: anterior extremityrounded: posterior extremity a little
rostrate. situated above the middle ofthe height: ventral margin evenly
rounded: surface ornamented with finenumerous concentric growth-lines: nodisinct carina on rostration: hinge teeth
discontinuous below umbo and very
minute below umbo: chonclrophore in·visible: anterior series of chevronshaped teeth nearly straight. about :{0in number: posterior ones a little arcuateand 50 in number: two short irregularly
disposed ridges running from umbo to·wards anteroventral margin and attaining nearly the midheight.

Text-Figure 2. Internal mould uf
Nucuhma (Praesacce/la) erinoensis (Kl:\tl'RA)
showing internal ridges.

1Heasurements :-Family I\uculanidae
hulutypc

Genus Nucu/ana Lt :XI<. 1807
Subgenus Praesaael/a Cox, 19cl0
Nuculcma (Praesaccel/a) erinoensis
Kt:-.tURA

Plate 6, Figures 3-6.
1956.

Nuculana (Rollieria.,) eriuoensis. KI:-.tt··
p. 84. pl. 1, figs. 3. '1.

RA.

Description.·-Shell medium sized forgenus. depressed. su beq u i lateral, elongately ovate in outline, with the length

L
24 mm
37
21

H

?

15

21

9

1-tmm
19

13

Obserl'ltliou and Comparison :-Several
internal and external moulds of bothvaln•s from the Sakamoto formation arc
larger than in the Torinosu group in
Sakawa basin. Partly due to deformation the shells vary in outline. Internalridges of this species are distinct. The
posterior gaping is seen in a specimen(Fig. 3). Rol/ieria has ovate in shape in359.

Taxodonta and Isodonta from the Upper Jurassic

general, while this form is elongate androstrate posteriorly. Therefore it isbetter located in Praesacce!la than in
Rol!ieria.
Palaeoneilo belae nsis Cox (1940, pI. 1,
fig. 1) from the Patcham bed in Cutchis allied to a specimen (Fig. 5) of thespecies but the posterior and anterior
series of denticles are continuous below
the umbo.
Occurrence :-Locs. L 4. :1. 6, ~l. 11. 1:2.

57

Nuculana (Praesac.) erinoeusis I\1 \WRA
which occur together. The smaller size,
more inflated form, smalier number ofchevron-shaped teeth and no irregularridges on internal surface in this species
are its distinction from erinoensis.
Occurrellce :-Locs. 1. 4. ll. 12.

Subgenus Dan~romya AGASSIZ. 18•!0
Nuculaua ! Dacryomya) stenodolic/zos
Kl\fi:RA

Nuculmza \Praesarcella) yatsushiroensis
T.\:o.n·R,\, r~e\v species
1956.

Plate 6. Figures 7. 8.

L
li.5mmII-!.Omm

6 (I

4.0

5.5
5.5

3.5
·15
4.5
4.5

6. I)
8. 0

Nuculana
1<1\ll'I<A.

De script ion :-Shell small for genus,
fairly com·ex. subequilateral to inequilateral. longer than high: umbo orthogyrate and almost medially situated ora little anterior to center: antero- andpostero-dorsal margins slightly arcuate
or nearly straight: ventral margin wellrounded: posterior extremity a !ittle
rostrate and situated above the midheight of shell, depressed: carina running from umbo to posterior extremity
bounding narrow depressed escutcheon:
surface ornamented with fine numerous
concentric lines: hinge-teeth probabl~·
discontinuous between posterior (about
Fi in number) and anterior sets (about
15) below umbo. posterior one smaller
in size.
:11easurcmeuts :holotype

Plate 6. Figures 17-19.

Comparison:- There are several internal moulds of both valves. son1e ofwhich are deformed. They are small 111
size. This species is closely allied to(Dacryomya) stenodolicllos.
p. 83. pl. L fig. I.

Oaurrence :-Several specimens of internal and external moulds of both
valves from Locs. -1, 11.

Family Pectinidae
Genus Clzlamys BoLTO:-< i\IS,
Ri:iol;-;r., 1798
Subgenus Chlamys s. str.
Ch!alllJS (C/ilamysi iboibo Kt-HAL\

and K1x11;EA
Plate (), Figures 35, 36.
1951.

Chtamys iboibo, K 1\It: RA. p. 339. pl. l,fig~. ~--L

One external and internal moulds ofa left valve and two broJ.:en internalmoulds of right valves are at hand.
Radial 10 ribs on right valve are bifurcating near umbo and their interspaces
on ventral side equally spaced. Some
Sakamoto specimens are about twice aslarge as the Sakawa form.
Occurrence:- Locs. 8, 11.
C!zlamys (C/zfamys) sp.
Plate 6. Figure 38.

Minoru TAMUR.4

58

Shell very small for genus (L : 6 mm.
Right valve subequilateral,strongly depressed, elongately ovate;hinge margin straight; postern- andantero-dorsal margins nearly straightand steeply sloping and forming about
70° angle; ventral margin rounded but
a little oblique to backward: ears
moderate in size: anterior a little larger
than the posterior. anterior and posterior
extremities acute- and obtuse-angled respectively; sulcation below anterior ear
indistinct ; surface scu lpturecl by 8 orlU radial ribs which are narrower thantheir interspaces and crossed by fineconcentric striae.
The right valve of Cll/amys (C/i.) iboibo
is similar to this specimen, but the small
number of radial ribs distinguishes thisfrom that species.
Occurrence-Lac. 6.
H: 9 mm).

Subgenus RadulojJec/en RoLLIEI{, 1911

Clzlamys (Radu!opecten) 11agatallensis
KuRATA and KIML-RA
Plate 6, Figures 31, 32.
1951.

all surface.
Comparison:- This species closely resembles Chlamys (Radulopecten)
inequicostatus (PIIILLIPs) from Osmington
Oolite from Yorks but the presence ofdistinct radial riblets on chief ribs of
the right valve distinguishes this fromthat species. Japanese Gloripallium fromthe i\Iiocene (G. izurensis 1\lAsuoA, 1958etc), is very alike this species. Therefore Jurassic Radu!opec/en may be ancestral to Gloripa/lium.
Occurrence :-Loc. 11.

Cll!amys (Radu!opecten) ogmceusis(Kn!FRA)
Plate 6. Figure ai.
1951.

1\1:-.1t;RA compared this species to
Ch!amys (Aequipecteu) fibrosa (Sow.) by
AIIKELL (1931).
A group containing
fibrosa is now included in Radulopecten(Cox, 1952).
Occurrence:- Two internal moulds ofboth valves from Loc. 6.

Chlam_,·s nagatakensis, K1:-.1URA, p. 338.
pl. ], fig. 1.

Description :-Left valve depressed.
slightly inequilateral, orbicular, longer
than high; hinge margin about l/2.5 ofthe length, straight: cars unequal, anterior one about twice or more thanposterior; two diverging radial ribletson anterior ear: extremity of anterior
ear nearly 90° and posterior one obtuseangled; sulcation below anterior ear
indistinct ; dorsal
marginsnearlystraight, forming about 100° apicalangle: ventral semi-circular; surface
sculptured by 8 radial ribs among which
middle ones are wider than laterals;
their interspaces nearly as wide as ribs:
very fine radial and concentric ribs on

Aequipecten ogawensis, KIMURA, p. 3·13,
pl. 1. fig. i.

Genus Aequipecten F1scHER".:lequipecten ·· llu!garis KIMURA
Plate 6. Figures 40, 41.
1951.

tlequipccten l'lllgaris.
pl. 1, figs. 5, 6.

Kl~lt.:RA.

p. 342.

Radial ribs are about 13 in the Sakamoto form and their interspaces sculptured by about 4 fine riblets.
Occurrence :-Several specimens from
Locs. 3. 4. 11.

"Aequipeclen ·• kotsubu (K1 ML'RA)
Plate 6, Figures 33, 34.
1951.

Neil/tea kotsubu. KI:-.IURA, p. 343, pl. 1.
figs. 8. 9.

359.

Taxodonta and Isodonta from the Upper jurassic

Description :-Left valve small, fairly
convex. inequilateral. a little longer thanhigh: hinge margin straight; anterior
ear larger than posterior one; anterior
extremity acute-angled and posterior one
obtuse-angled: byssal sinus below anterior ear indistinct; two radial ribletson anterior ear divergent from umbo:
anterior dorsal margin straight, longer
than a little acute posterior one: beaka little projected beyond hinge margin:apical angle about 90°: ventral marginrounded and a little produced anteriorly:
surface covered by fiat-topped about 22
radial ribs, their interspaces wider thanribs.
Comparison:- The Sakamoto specimens
are more inequilateral than Sakcnva form
but it is evident that these specimens
are allied to lwtsubu. These specimensfrom the Sakamoto area are included in" Aequipecten ·· because of biconvexityof the valves.
Occurrence :-Locs. 3, 4, 11.

Genus Camptonectes MEEK, 1864
Camptonectes sp. aff. brozcni Cox

59

ous umbo and coarse radiating threads.
The sole difference is the lateral gaping of the ear of this specimen.
Oaurreuce .--Loc. 6.
Camptonectes ? sp.
Plate 6, Figure 39.

An external mould of a left valve
slightly broken in hinge part, very small
for genus, orbicular in outline, nearlyflat: posterior and anterior lateral
margins nearly straight, rounded. alittle obliquely elongated backward:
hinge not clear. dorsal margin straight;
beak not reaching dorsal margin: surface covered by 9 erect concentric
laminae at regular intervals which are
obsolete near umbo.
The regular concentric laminae of thespecimen somewhat resemble the ornament conspicuous of Camptonectes annulatus group but radial threads on surface
are invisible in this specimen. This solespecimen is verv small (4 mm high. 3
mm long) and its specific characters areimperfectly known_
Occurrence :-Loc. 8.

Plate 6, Figure 42.
aff. 1935. Camptonectes browni, Cox, p. 171.
pl. 18. figs. 13a, b.

Left valYe (34 mm high and 30 mmlong) subequilateral, fairly inflated.
nearly orbicular: umbo prosogyrate, alittle projected beyond short hinge
margin: ears neither large nor prominent: anterior ear inflated and gaping
laterally, not delimited from the shell
body: surface covered by radiating
threads. coarser than the Camptonectes
ornament, and by obsolete concentricribs at irregular intervals.
The specimen closely resembles
Camptonertes browni Cox (1935) from the
Callovian of Somaliland in its prosogyr-

Genus Fopecfen DotcYILLf, 1897
Eopecten sp_ new
Plate 6, Figure 49.

Left valve small (H: 13mm. L: 14mm).
inequilateral, orbicular, moderately convex and elevated near umbo: dorsal
margins nearly straight. a little longer
in anterior than the other: ventral alittle produced anteriorly and orbicular:
primary riblets fine, 20 or more: secondary finer threads intercalated.
Ears are not clearly defined from theshell body. Surface ornament is characteristic of Eopecten. Ve!opecten rollei
STOLL. (PcELr:-.cE\·, 1937) from Pliensba-

60

Afinoru TAMURilchian of South Ossetia of L S. S. R.
resembles this specimen but concentric
plication is weaker or less in the latter.
Occurrence :-Only an internal mouldof a left valve from Loc. 11.
Family Amusiidae

the Sakamoto area shows distinct radialribs. A byssal gape below the anterior
ear is fairly deep. Therefore it is evident that this species belongs to Variamussium SAcco instead of Propeamussium GREGORIO (PHILIPPI, 1900).
Ocwrrence :-Locs. 10. 1~.

Genus Variamussium SAcco. 1897

Genus Entolium F. B. 1\lEEK, 1865

Variamussium lwbunokazceuse (Kl~IL:RA)

Ento!ium yatsujiense KtiRATA

Plate 6. Figures 20-22.

and K1~1uu

1951.

Propeamussium habunokawe>1se. KI~Il'l'!:\.
p. 344. pl. 1. figs. 14. 15.

Description :-Shell small. subequi lateral, depressed. slightly higher thanlong. Right valve depressed but moreconvex than !eft; hinge margin fairly
long. straight; anterior one twice ormore than posterior: anterior and posterior lateral margins a little concave.
forming about 100° apical angle: ventral semi-circular: ears fairly large.
depressed and distinctly marked frombody: anterior ear large; byssal sinus
below anterior ear fairly deep: surface
sculptured by numerous fine regularconcentric lines: about 9 elevated ribs
on internal surface a few of which arc
restricted to ventral side: these internal
ribs do not attain to yentral margin.
Left valve similar to right valve but
has about 20 or more radial ribs. In
each interspace 1 or 2 finer ribs are inserted and intersected by numerous
regular concentric lines: these radial ribs
impressed feebly on internal surface.
Comparison:-This species was grouped in Propeamussium by KI~IPI~,\. as theradial ribs on the left valve arc not of
Vm·iamussittm. But the internal feeble
riblets (KI~n:RA, 1951. pl. 1, fig. 15) suggest the presence of radial ornamentson the surface of the left valve. An
imperfect external mould (Fig. 21) from

Plate 6. Figure 30.
1951.

Entolium yatsujiense.
pl. 1. figs. 18a. b.

Kl~ll'RA.

p. 3·15.

This is involved probably in thegroup of Entolium cingulatum GoLDF.
(ST.uscHE, 1926) by the presence of apair of distinct internal ridges close to
the auricular margins. The shell of the
Sakamoto form is variable in size (4mmto 10 nun in height).
Ocwrrence: -Lacs. 6. I, 9. 11, 1~. allin the western half of the area.

Entolium l?imurai T,\;..ll'RA. new species
Plate 6. Figures 23-29.

Description :-Shell medium to small
for genus. cquivalve exclusive of hingearea. equilateral. depressed, elongately
ovate to orbicular in outline and higher
than long in general: dorsal margin
short and straight in left ,-alve but
rises above hinge margin in right valve;ears small, equal and their extremities
roundedly obtuse-angled and depressed:auricular margins short. slightly arcuate
or nearly straight and forming nearly
90° apical angle: ventral margin ovate:surface smooth: internally, auricularcrura short but distinct: internal ridges
obscure near auricular margins; winglike elevation near umbo present in

359.

Taxodonta and Isodonta from the Upper Jurassic

each ear.
Jfeasurments: -·holotrpe

L
14 mm
18
12
14
11
9

H

Apical angle

18mm

90"

19
14
13

100
100
110

lG

90
80

12

Obsen•ation :-\hny specimens in handare deformed in some degrees but theirmorphological variance can not be denied. In some specimens (figs. ~4. :;6,
27. 28) the apical angle is 100° or more
and height nearly equal to length.
These specimens arc inseparable fromthe typical form. l\leasurements andFigs. 23-29 sho\\' morphological varianceof this species.
Comjmrison :-This species somewhat
resembles E. japonicum Kn~. and K1~1.
from the Sakawa basin. The latter.
however. has a smaller apical ani-!lC(about 70°). its anterior car is larger
than the posterior and the dorsal marginof japonicum docs not rise above 1hehinge margin. En folium demissum P 1111. 1..
(STAESUIE, 1926; AI~I,EJ.L, 1929) and E.
disc~rormis ScHL'EB.

(DEcJL\SEALx.

1936)

are closely allied to some forms of thisspecies (Figs. 211- 28). But fine growthlines are destitute in this species andthe shell is much smaller and generally
not so circular as in these species.
Occurrence:- i.\1lost abundant and wide·
ly distributed in Sakamoto area. Locs.
2. 4. 5. 6. I. 9. 11. 12.
Genus Somaj}(!l.·lcn KI:-.II'IL\. El;)l
Type-species: Somapeclen lwmimancnsis
KntL'RA.

Diagnosis :-Shell equivalve exclusiveof hinge area. equilateral. depressed but
biconvex, elongately ovate and fan
shaped, higher than long; ears equaland fairly large for the family, theirGl

corners rounded and obtuse-angled:
dorsal margins in right valve rise above
the straight hinge margin: surface
smooth; internally auricular crura present; a paired triangular wing-likeelevation below hinge margin: strong
angular conical tooth found between
paired pteriform elevations in right
valYe and a corresponding socket in left
valve; lower surface of the tooth grooved.

Tcxt-Figurl' 3. Somapccten lwmimaucnsis
exterior of left vah·e (a) interiorof left vahl' (b). interior of right valve (c).
KI:-.JL'RA:

Remarks:- Jurassic l~'ntolium and Late
Palaeozoic Pemopecteu ~:\EwEu.. 1937)
arc the group having smooth surface
and no ribs internally in the Amusiidae.
though the two diverging distinct internal ridges near auricular margins arepresent in I he group of Entu/ium
cinf.!u/atum (Go~.nr.) and the latter may
be ancestral to the former. Somapecten
is very akin to Entolium by its orbicular. compressed. subequivalved equilateral shell and smooth surface. except forthe peculiar tooth and socket. Dorsal
margins of the right valve in Entoliumand Somapecten rise above the hinge
margin, though it can be seen in theleft of PenzojJec/en (anterior and posterior direction are based on weak adductor scar in Somapecten). Two divergent
auricular crura and paired wing-likeelevations helO\v the hinge margin are
also common characters between bothgenera. Whether it belongs to theAmusiidae or not is a problem because
its cardinal tooth in right valve and its
socket in left have never been describedin the Amusiidae. Kn,HJRA comparedthis genus to Ento/ium and referred it
to the Pectinidae. Here the writerplaces it in the Amusiidae owing to its
resemblance to Entofium except for the
tooth and socket.

lateral margins are unkno\Yn. A long but
narrow axial elevation from umbo to
midheight probably corresponds to thetooth and its extension.
Family Limidae
Genus Lima BRt.:GVIERE. 1797
Subgenus Plagiostoma SowERIIY, 181,1
Lima (Plagiosfoma) sp.

Somapecten kamimanensis 1\.1 ~n; RA

Plate 6, Figure '18.

Plate 6. Figures 50-55.
1951.

Somapeclen kamimanensis.
347. pl. 1. figs. 19. 20.

KIML'IL\.

p.

Descriptioll :-Shell medium. equivalve
exclusive of hinge area. depressed andbiconvex, elongate!y ovate or orbicularin outline: ears equal. depressed, demarcated from shell body, fairly large:
auricular margin with shell body long:
dorsal margin in right valve rises above
hinge margin but straight in left valve:
extremities of ears roundedly obtuseangled in both valves: dorsal margins(or auricular margins) straight, fairly
long and forming 80-90° apical angle:
ventral margin orbicular and fan-shaped:
surface smooth: test thin. having very
minute radial and concentric structure:internally, auricular crura short andimprominent; paired triangular winglike elevations below hinge margins:angular conical cardinal tooth, grooved
at base. projected in right valve. andcorresponding triangular socket in left
valve; resilifer not demarcated from thetooth or socket.
ObserL>ation :-Several specimens at
hand vary in size. some of which being
deformed. As Kl~IURA stated, there are
two kinds of shell outline in this speciesof the Sakamoto area. i.e. quite orbicular form and ovate form, much higher
than long. Most Sakamoto specimens
belong to the latter. Gapes on anterior

A broken external mould of a left
valve which lacks hinge area is referred to Lima (Pfagiostoma). It is very
inequilatcral, a little convex. trigonallyovate, length much greater than height(L: Hi mm. H: 11 mm); antero-dorsal
margin straight and three times as large
as posterior, forming ll0° apical angle;
ventral margin rounded and antero-ventral margin projected: surface coveredby about SO radial ribs which are wider
than their punctate interspaces. The
obliquity of shell, many fine radial ribs
and punctate interspaces of the specimen are all characteristic of Plagiosloma.
although the hinge area is invisible.
Occurrence :-Loc. 11.
Subgenus Ctenoides l\16rch. 1853
Lima (Ctenoides) tosana Kn~ATA

and K1~1t.:R.\
Plate 6, Figures 44-47.
1951.

Lima (Cienoides) tosana.
349. pl. 1, figs. :!2a. b.

Kll\IL'RA,p.

Occurrence :-Common at Locs. 4.~6, 11,
12.

Genus Lima/it/a W ooo, 18:19
Limatufa reticulata T_..,_\IURA,
new species
Plate 6, Figure 43.

359.

Taxodonta and lsodonta from the [Jpper jurassic

Description :-Shell inequilateral. inflated. elongated. and height much greaterthan length: hinge margin short andstraight: antero-dorsal margin slightly
arcuate or nearly straight : posterodorsal a little rounded: ventral rounded
and produced: beak distinct but not
pointed. a little projected beyond hinge
margin: ears small. anterior one larger
than posterior one. not delimited fromshell body. extremity of anterior ear
obtuse-angled and posterior one nearly
90°: surface covered by about 18 regularridged radial ribs which arc restricted
to main part of shell body: its lateralsides smooth: posterior side of rib alittle narrower than anterior one andboth sides striated by numerous fine reticulate ribs. inserted by low secondary
ridged radial ribs.

u

r
I

--~>A

1

2

~
R
r

II

Text-Figure .1. Radial rib of Limatula
reliculata TAllfl"RA:I : side view. II : profile of rib. 1-2:
cutting place. A: anterior, U: upward.
R: primary rib. r: secondary rib.

Comparison:- The external and internal moulds of a right valve (L: 10 mm:
H: 2lmm; apical angle: 50°) are present.
The tall shell form and surface ornament as seen in Fig. 4 are characteristicof this species. It resembles Limatula
gibbosa by SO\\·. i.MoR. & LYe .. 1853) but
it is much obliquely expanded and thesecondary ribs are inserted bet ween
primaries. Limatula coral!ina ARKEL L(ARKELL, 1929! has no secondary ribsand L elliptica ('WiiJTEA\'Es) (i\Rf(ELL.

63

1930) differs from L. reticulata, in the
striae of i nterspaces.
Occurrence :-Loc. 11.

References cited
ARK ELL. W.]. (1930).
The Generic Posi·tion and Phylogeny of Some Jura8sic
Aridac. Ceo!. Mag., Vol. 67.
DECH.\SE\t:x. C. (1936), Pectinides Jurassi·
ques de l'Est du Basin du Paris .. Ann.
Paleont.. t. 25.
FIEflELKOR!'\. M. (1893). Die norddeutschen
Geschiebe der Oberen Juraformation.
7eits. Deutsch. Geof. Ges., Bd., 45. Berlin.
HEALEY. M. (1908), The Fauna of the Napeng Beds or the Rhaetic Beds of Upper
Burm:-t. Palaeoill. Indica, N. S .. Vol. 2.
1llem. No. ·1.
KtTTL. E. (1903). Geologie der Umgebung
von Sarajcbo. ]allrb. k. ll. geo/. Reichsanst.,
TYien, Vol. 53.
lVIASlT>A. K. (1958), On the Miocene Pectini·dae from the Environs of Sendai, Pt. 11.
Trans. Proc. Palaeont. Soc. japan. N. S.,
I\io. 31.
NEWEL!.. N.D. (1937), Late Paleozoic Pelecy·
pods : Pectinacea. Kansas Geol. Sun• .. Vol.
10.
PcF:I.Jl'\CEV. V. (1937). The Gastropoda and
Pelecypoda from the Liassic and lower
Dogger of the Tetis in the limits of the
USSR (the Crimea and Caucasus).
Paleont. USSR Monogr., Vol. 48.
P!ltLIPP!. E. (1900). Beitriige zur Morphologic
und Phylogenie der Lamellibranchien:
Zeits. Deutsch. geol. Gesel!s.. Vol. 52.
STAEscrm. K. (1926). Die Pectiniden derschwabischen Jura. Geol. Pafaeont. Abh.,
N. F, Rd. 15.
TA~IVRA. M. (1959). Trigoniidae, Ostreidae.
Bakevelliidae, Pteriidae, Cardiidae andAstartidae from the Upper Jurassic
Sakamoto formation in Central Kyushu,
Japan. Trans. Proc. Palaeon/. Soc. ] apan.
N. S., "Vo. 33.
TERQUEM. 0. (1855). Paleontologie de l'etage
infcricur de Ia formation liasique de Ia
Province de Luxembourg. Grand-Duchelvlinoru TAMURA

64(Hollande), ct de Hettange. du Ia Mosel·!e. !llim. Soc. gl;ol. France. Si:r. 2. Tom. 5.
TRoEosso:-<, G. (1951). On the Hoganas
Series of Sweden. l\.tmg!. Fysiogr. Still.
Hand/., N. F. Bd. 62. Nr. 1.

See also ARKELL (1929-31). Cox (1935, 19-10,
1952), KIML'I~A (1951, 1956), MoRRIS and
LYCETT (1853) in Bibliography of Trans.

Proc. Palaeont. Soc. japan. N. S .. No. 33
of this study.

Explanation of Plate G(All figures show side view unless denoted)

Grammatodon lakiensis K1 ~~ L RA
Fig. I.
Fig. 2.

Internal mould of a right valve: Loc. !J. x2. (1•11•1 3013).
Internal mould of bivalved ;;hell: Loc. -1. x2. (l\•IM 3011).

Nucufana (Praesaccel/a) erinoensis Kl~ltoRA
Figs. 3. ·L Internal mould and clay cast of external mould of a right valve: Loc. 5.
;d. (l\1}.! 3017 ).
Figs. 5, 6. Internal moulds of !eft valves: Loc. 2 (Fig. 5), 6 (Fig. 6). x 1. (i\IM 3018,
3019).
Nucrtlana (Praesacc:e!!a) ya/sushiroensis TA:o.JUR,\. new species
Figs. 7, 8. External and internal moulds of the holotype right valve: Loc. 2. :.-: 2. (?liM3020).
Paral/e/odon iufla/us T.·\:>.Jl:RA, new species
Fig. 9. Internal mould of a right valve: Loc. 3. :d (l\L\·1 3022)
Fig. 10. Internal mould of the holotype right valve: Loc. 6. X 1. (MM 3023).
Calel!a (Torinosucatella) kobayashii 'L\MURA, new species
Fig. 11. External mould of the holotype right vah·e: Loc. 6. x2. (l\IM 302-1).
Figs. 12. 16. External and internal moulds of a left valve of a bivalved she!!: Loc. 6.
> 2. (l\1!\1 3025).
Fig. 13. External mould of a left valve: Loc. 6. x 2. (MM 3026).
Fig. H. Internal mould of a right valve; Loc. G. x2 (?viM 3027).
Fig. 15. Internal mould of a left valve; Loc. 11. x2. (l\1M 3028).
Nuculana (Dacryomya) stenodolicltos KicvJURA
Fig. 17. Internal mould of a left Yalve: Loc. 12. :<2. (J\Il'vl 3029).
Fig. 18. J<:xternal mould of a right valve; Loc. ·L x2. (MM 3030).
Fig. 19. Slab with specimens: Loc. 4. >: 1. (M!\1. 3030).

TAMURA :Plate 6Upper Jurassic Taxodonta and Isodonta

1

20

395.

Taxodonta and Isodonta from the Upper jurassic

65

Variamussmm habunokau:ense ( K1 ~~ UR A)
Figs. 20. 2:!. External and internal moulds of a right valve: Loc. 12. x2. (l\ll\1 3031).
Fig. 21. External mould of a fragment of a left valve: showing radial ornament: Loc.
12. X 2. (Ml\1 3032).
Entolium kimurai TA~·IL'RA. new species
Fig. 23. Internal mould of a left valve: Loc. 12. xi. (MM 3035).
Figs. 24. 26. 27. Internal moulds of leit valves: Loc. G. ,.. I. (J\Il\1 3036. 3031. 3038).
Fig. :!5. Internal mould of a left valve: Loc. 2. X 1. (l\Jl\I 3039).
Fig. 28. Internal mould of a right valve: Loc. 2. X 1. (MM 3040).
Fig. 29. Internal mould of the holotype left valve: Loc. 6. xl. (l\I.M 3041).
Entolium yatsujiense Kl:RAT.\ and KI:-.tl'I~A
Fig. 30. Internal mould of a left valve: Loc. 12. x2. (l\111 3045).
Chlamys (Radu/opecten) nagalakeJJ.~is KtlJL\T,\ and KI:\IURA
Figs. 31. 3:!. Extern:d and internal moulds of a left valve: Loc. 11. X 1. (Ml'vl 304i).
"Aequipecten .. ko/subu (Kr:\WRA)
Fig. 33. Internal mould of a left valve: Loc. 3. x2. (l\ll\I 3048).
Fig. 31 External mould of a ril-(ht ,·alve: Loc. 11. x3. (MM 30-19).
Chlamys (Chfamys) ifwibo KuR,\'L\ and KI~IL'RA
Fig. 35. lntl.'rnal mould of a left valve: Loc. 11. x2. (1\E\1. 3052).
Fig. 36. Internal mould of a right valve: showing upper part of the shell: Loc. S.
x2. ('\lM 3053).
Ch/amys (Radulof>ecten) ogmcmsis (I\JMl'J(A)Fig. 37. Internal mould of a ldt va!Ye: Loc. 6. xl. (l\E\1 3055)
Chlamys (Chlamys) sp.
Fig. 38. Internal mould of a right valve: Loc. 6. X 2. (l\IM 3057).
Camptonectes ? sp.
Fig. 39. '\lodeling cast of the external mould of a left \'alve: Loc. 8. x3. (MM 3058).
"Aequipecten·• mlgaris (Kr~Jl'RA)
Fig. 40. Internal mould of a left \·a lYe: Loc. 4. x 2. (1\1:\I 3059).
Fig. 41. Internal mould of a left val\'e: Loc. 3. x:!. (l\ll\1 3060).
Camf>lonectes sp. aff. brmcni Cox
Fig. 4~. Left \·alve: Loc. 6. X I. (!\IM 30!i3).
Lima/uta reticula/a T.\:-.Jl:J(A, new species
Fig. 43. ;\[odeling ca~t of the external mould of the holotype right vah·e: Loc. 6. xl.5.
( Ml\1 3064).
Lima (Ctenoides) tosana KI~Il'RA
Figs ..J.I, -15. Internal and external moulds of a left \'alve: Loc. ll. x2. (Ml\1 3065).
Figs. -16, 47. Internal mould and clay cast of a right valve: side view and showing
posterior lateral :;ide: Loc. 4. X 1. (MM 3066).
Lima (Plagios/oma) sp.
Fig. 48. Plaster cast of the external mould of a broken left valve: Loc. 11. x 1. (Ml\13067).
Eopel'/cn sp.
Fig. 49. Internal mould of a ldt Yalve: Loc. 11. x2. (M?vl 3068).
Somapecten kamim011ensis K 1~Jl' R A
Figs. 50, 53. Internal moulds of right ,·al\'cs: Loc. G. x L (M).I 30G9. 30;"0).
Figs. 51. !i-1. Internal moulds of left valves: Loc. 4 (Fig. 51). 11 (Fig. 54). x 1. (l\lM3071. 3072).
Figs. 52. 55. Left valves: Loc. 6. xi. (l\IM 3073. 307·1).
All specimens are stored in Geological Institute. University of Tokyo.

Trans. Proc. Palaeont. Soc. Japan, ~. S., Ko. 34, pp. 66-/7, pl. 7, June 15, 1959

360. PELECYPODS OF THE MIZUNUl\IA JURASSIC IN .MIY AGIPREFECTURE. WITH SOl\IE STRATIGRAPHICAL RK\IARKS*(Studies on the Liassic Pelecypods in Japan. Hl)
ITARU HAYAlVII
Geological Institute, Uni\-ersity of Tokyo

7l<i?!±ilD50:; .:t. 7 ~.C~JEfil: '§'~!liHl1JHi!.l<f2.tU!1Jii:.:;tf(1*+0!-l.i~ ~~ ia ?"t;t:'i$!1J.ttl!1.i
01!!/ ~m'fH!illr.Jtii!it..:UiJEftl 'i ~i!lt-:r;;:, :J1ll/f4n:.?_, 7... J:f:f.Uff,'JIC Camptonectes (s. s.). Bur·
mesia. Cuspidaria (?) 0¥frmin:if:> 1.> O)"(,l(l~-g- J.,. Burmesia l:t [. 0.ttl!1J"t':;t Geratrigonia
lwsourensis «f0r«H:~-t7.>. [.O)~I.:ti:'JL-70) ::\apeng lfli"t'fti& ~~1.7.>JIU?;i7:/·70
Noric £t:l;t Rhaetic IC.fflrJ!k(.!':JtC:}l!i;tL"t~'7.>~-c'ib7.J0-c' i:\apcng ilib~U~~c0MlCU:~

J'il.a.ilii'l t- t~. <:. 0 ftT:i®0--·11ill;tf,HIH't~flitH~ ~~ i; ;/1,. 1:-:; -tl- c At X.; :h -n, UJ:. ftE
fill, IP.'lf§0J-i.P .::,;jfi.J ~/ftitc;tllt *tL7.> O)"t', ~.!ll!1:i0rffif:f.!&7.H: lf!H~.~~;tjlJ~M'i~T;;,. ~~:.:t 7Jll0~~~:1ff1' 7.> :YJi::L'J>;;, t;:, .::. 0 ltEIOOOYFti.U:.ib .0 J_9:t 'li'Y!MISLtJ:$.=:1i*C'ib 7.>
ilJtref!l:n:iffi!<. :;;t.=:;*r:::.;,t;iJtJIIil!r1Jc7.'1A.cflllt:.lri1ri~!&5tn:iiim~tt.7.>.
1ru*

In ~Iizunuma area of Inai village,l\liyagi Prefecture, Jurassic deposits
show a horseshoeshaped distribution.
This area occupies the southern part of
the western synclinal belt of the Kitakami Jurassic (KonA YASHI. 1948) and islocated at the northeast of the wellknown locality of Anisic ammonites at
Inai. Since hAI and T\KAilASHl (1940)
had commenced the stratigraphy of thisarea. the Jurassic sediments were investigated by YosJIIDA (19 111. l\fS) andI-1."-=-DA (1953. MS) whose works werebirefly cited respectively by KoBAYASHI(1948) and 0=-uKl (l!l56). Their results
agree with one another in the majorclassification and distribution of strata,
although the nomenclature is confusing
to a certain extent.
Lately I surveyed this area and collected fossils. As the result it was
found that the stratigraphical divisionand chronology of this Jurassic require
some emendations. In this paper I re--------

mport the brief outline of the stratigraphy
and describe some new pelecypods.
Interesting are the occurrences of Camptonectes (s. s.) and Burmesia in the lower Liassic beds. Although fossils of
this area are strongly deformed bycrustal movements, most of them are
specifically determinable by close comparison with the better preserved Niranohama fauna already described hy Yo1\0YA~IA (1904). KoBAYASHI and !\IoRI(1954) and myself (1957a, b, l958a, b, c,d).
Here I express my most sincere thanks
to Prof. Teiichi KonAYASIII of the University of Tokyo for his kind advices andsupervision of this manuscript.
Stratigraphical Notes

In the l\Iizunuma district the sediments from Upper (?) Triassic to 1\Ialm
form a syncline. "Se:ymourites" at Ishizaki is a solitary ammonite, but bylitho!ogical resemblance the Jurassic
sequence of Mizunuma can be correlated* Received Aug. 22. 1958; read Sept. 27. 1958.

G6

Pelecypods of the ivlizunuma jurassic

360.
Table 1.

Division and Correlation of Mizunuma Jurassic,I _ _Shizukawa
Area_ _ _ __

1\·Iizunuma Area
1:--:AIand TAI\AIIASHI (1940)

I--~----

SamuraiI Owada sh.
hama gp. 1
I______I

Mano gp.
Shizukawa
gp,

67

I·LWAMI(H133)
iI em.MAnL;TI
11'AI (1939~~ _(1959)

h' Sodenohama fmt.
Maim
as I·'
1
ura , Arata fmt.
Aratozaki fmt.
gp.
A t
k' f t
Dogger___ ____
ra oza I m _·- - l - H

Arato fmt.

1

I

lMizunuma sdy. sh.[- -hiatus: Shizu- I llosoura fmt.
--· J\lizunuma fnlt.
kawa If
Niranohama mt.
Mizunuma sh.
Xir<1110hama fmt.1 gp ·?l'iizunuma ss.
Inai group[ Standard

Saragai fmt.

S~mt.

lnai grouplnai group

1(Aalenian)

I L'

tas

1

-~ Xoric---I

AnisicSky tic----

with that of the Shizukawa district, asshown in Table 1.
In this area there are more than 300
meters' more or less arkosic sandstones
below the Niranohama formation whichcontains the typical Niranohama fauna
and is considered the lowermost Liassic.
This formation is mainly composed ofbituminous shales and fine sandstones
besides a thin conglomerate at the base.
As a certain disconformity can be expected below the conglomerate, I am
inclined to consider that the underlying
barren sandstones are the correlative to
the Upper Triassic Saragai formation of
Shizuka\va area whose upper part has
been firmly dated as ~oric by the abundance of Manolis (Entomunotis).
The Niranohama formation of thisarea contains the following pelecypods
at Futamataji, a small valley. northeastof the hamlet of :Mizunuma.
Parallelodon niranohamensis HA YA!\11*
Modiolus bakevelloides (HAY A~ll)*Ballet•ellia trigo11a (YOKOYAMA)*
Gen•illia (Cultrinpsis) slti:zukawensis IL\ YA·~II

Jsognomrm riku:zm:icus (YOKOYA:\IA)*Cmnptonectes (s. s.) i11e:rj>ectatus HAYA!\11,

new species
Geratrigonia ltosourensis (YoKOYAMA)*
Homiodon lrmulatus (YoKOYA'-'IA)*
Eomiodon vulgaris HAY:\~~ I*E'omiodon (?) giganteus HAYA:\11*}'okoyamaina elliptica (YOKOYA!\1.'\)*
Tltracia subrlwmbica HAY A!I<II*
Cuspidaria (?) praenipponira 1-IAY,\MI. newspecies**Burmesia }aponica 1-I A YA:\I I, new species**

Among these 14 pelecypods. 12 species
marked by one or two asterisks arecommon to the "cyrenoid-fauna .. of thelower Niranohama formation of Shizukawa area. Although no vaugoniidsanclstone is represented here, the re·semblances of the specific assemblage
and lithology suggest that the two
faunas are almost coeval. At Futamataji, the following sequence of this formation is found in descending order.
25m+.

Light grey medium sandstone (barren of fossils).

* These forms were already described on
better presen•ed specimens from Niranohama and some other localities. and their desc·
riptions are mostly omitted in this paper.
** Several specimens from Niranohama
are identifiable with these species.

G8

Itaru H4YAM1Black bituminous shate with fo.fodiolus. Thracia and Cuspidaria (?).
11m. Black fine sandstone with Para!lelo·don.JI!odiolus, Baket·ellia, Gerrillia. !sognomon. Camptonectes. Geratrigonia,
Eomiodon tzmulalus, H. mtfgaris. Yo·
koyamaina, Prolocarclia.
30m. Black bituminous sandstone and shale(barren of fossils).
12m. Black bituminous shale with Bake·z:e/lia, Eomiodmz vulgaris. Cuspidaria(?) and Burnll'sia.
35m. Black tine sandstone (barren of fossils but for plant fragments).
2m. Basal conglomerate containing nu·
merous pebbles (';'em. in max. diameter) of underlying rocks.
- - disconformity - Dark grer sandstone of the Saragai (?)
formation.
6m.

This locality has hitherto been includedin the .. :\Iano group". b:AI and TAKA·IIASIII (19,10) listed ilrcomya sp. (aff. A.
cornuta ~vi.), Pleuromya sp. (cf. P. recurw(;oLDFJTss).
Jl1rzcrodmt cf. hirsonensis
o'ARciiiAc and Gen•illia sp. (cf. Gen•z'flia
ferruginea B~-:~Eci-:r-:) from this horizon
and suggested Dogger for the group.
Many other fossil localities are zonall~~traceable in this area from Futamataji
to the northern slope of Kusakariyama(315.0 meter's peak) where I (195/bl reported Gen•illia (Cultriopsis) shizuluauensis
and Gerl'illia sp. These localities are
considered almost of the same horizon.
Anyhow. the pelecypod fauna at Futamataji is lower Liassic instead of Dogger. and the '' :rvlano group " is at leastin part synchronous with the Shizukawa
group.
It is interesting that this fauna is
fairly similar in the generic assemblage
to the Rhaetic (or Noric) :\lapeng faunaof Upper Burma and its equivalent in
Indochina. Parallelodon. Bakez,ellia, Ger·
l'illia, l sognomou. Thracia, Cuspidaria I?)
and Burmesia are important constituentsalso in that fauna. But the :'\apeng
fauna is characterized by Bakeve/lia
praecursor and "Pteria" contorta. which
are considered important Rhactic indices,while the present fauna lacks any Tri·
assic clements.
The occurrences of
Bunnesia have been restricted to theUpper Triassic of Southeastern Asia
(Burma, Indochina and Molucca) andJordan Valley (?), but Hrmnesia japmzica.
n. sp. is probably a lower Liassic
species. because in Shizukawa and thisareas it is found in one bed altogether
with Eomiodmt and other pelecypods
which are quite different from Upper
Triassic faunas hitherto known in Japan.
The resemblance between the Napeng
and the present fauna may be primarily
due to simi far sedimentary environments.
This presumption is endorsed by the
Shinatani fauna in the Kuruma groupwhich is dated as Domerio-Toarcian but
contains also somewhat simi Jar genera
to the Napeng and Niranohama beds
(KooAYAsiii et al.. 1957). I made someother stratigraphical and tectonic observations in this area, but the rcsulls will
be reported on another occasion.
llescription of Species

Fam i Iy Para llelodon tidae DA 1. 1.
Genus Parallelodon 1\iEEK and\VowmE:-;, 1866
( = l\facrodo11 BucK ~IA;o;, 18-H.
11011 Mi'LI.ER,

1842)

Para/le/odon uiranohamensis HA YAM I
Plate 7. Figures 1, 2.
1958. Para!lelodmz

11iranolwmensis HA YAJ\I I.
Japau. four. Ceo/. Geogr .. Vol. 29, Nos.
1-3. p. 100. pl. 7, figs. 1-4.

An internal mould (Fig. 1) shows nearly vertical granular median denticles
and weakly crenulatcd subhorizontal

360.

Pelecypods of the Mizunuma jurassic

elongated posterior teeth. An externalmould reveals numerous fine radial
threads and irregular concentric growthlamellae. The holotype from Shizukawa
area has a more similar dentition to
Para/le!odon rugosus rBL·cK:o.tA:-;) in !\.RKELL (1930) than .·lrca keyserlingii D'ORBrc:-;Y in Arn;ELL. as noted before. Then
I considered that the inclination ofmedian denticles is important and that
Cosmetodon BR,\:-;sn:--: (19·1~) ( =Beushausenia in AHKELL's sense) is subgenerically distinl-{uishable from Parcrllr>lodon(s. s.) by the divergent median denticles
from the base of hinge-plate as in Gramma/odon. even if the undeveloped posterior wing. which was regarded as thesubgeneric character of Heuslzausenirt by
ARKELL (1930). is not a diagnostic criterion. According to Cox's personalcommunication* received on 2Gth. f\Iay,1958. however. no generic or subgenericdistinction can be based on the hingeteeth. which are very similar between
P. rugosus and Area keyserlingii D'ORBrcNY. type species of Cosmelodon BRM.:SON (1942).** In the inclination of median
denticles these Mizunuma specimens
are somewhat different from the halotype and fairly similar to Parallelodon
buckmani RrciiARnso:--; in ARKELL (1930)
from the lower Lias of England. But it
is only due to intraspecific variation. fortheir outline and surface ornaments an~
the same to the Niranohama specimens.
It is concluded that the dentition ofthis species is fairly variable and that

* I am greatly ind<.:bted to Dr. Leslie H.
Cox of British :Yiuseum (Natural History)
who kindly gave me reply to my questions
on Parallelodon and some other pelecypod genera.
** In my opinion Cosmetodon BRA:'>SO:'\. if
the subgenus is valid, is not acceptable asa substitute of Beuslumsenia Coss~·!A1\'X (1897).
because of the different type species.

69

the difference in inclination of medianclenticles generally does not serve for
distinction of subgeneric or higher
category in para1lelodontids.
Ocrurence:-Rare at Futamataji. northeast of i\'lizunuma.
Family Bakevelliidae Kr:-;cGenus Balm,e!lia Krxc;, 1848
Bakez•ellia cf. trigona (YoKOYA:O.tA)
Plait: 7. Figure 3.
cf. 190-l, Gerl'illia trigona YoKoYA~lA. jour.
Col! Sci. Imp. Unit•. Tokyo. Vol. 18.
Art. 6. p. 12. pl. 2, t1gs. 7 and 8 (?).
d. 1957. BaluJre/lia trigona. HA YA)\1!, japa11.
]our. Gcol. Geogr .. Vol. 28. Nos. 1-3.
p. 51. pI. 2. figs. 1-5.

Represented by an internal mould ofleft valve fMiVI 292G. 88.5 mm. long:
51.0 mm. high: 11.5-7-mm. thick). Shelllarge for genus, reverse trigonal, moderately inflated. much longer than high:hinge-line as long as shell: posterior
wing small. flattened. defined by slightly
sigmoidal postero-vent raJ margin: hingeplate narrow. provided with one or two
oblique terminal cardinal teeth and acurved weak posterior lateral: ligamentarea moderate in breadth, faintly striated subhorizontal lamellae. provided with
7 or more slightly opisthocline quadrate
ligament pits arranged almost equidistantly.
This specimen is ur:doubtedly compressed secondarily in dorso-ventral
direction. In the large size and terminal
cardinals. this resembles BaketJe/lia magnissima 1-l." YAW (195/a) from the Domerio-Toarcian of Central japan. but
coincides with lrigona in other characters. Judging from its age, this may
be a transitional form from trigona tomagni ss ima.
Occurrence:- -:\:izunuma formation at

70

Itaru ll4 Y.4MI

the north of \Iizunuma, more or lessyounger than the Hettangian i\iranohama formation.
Family Pectinidae Lu.L\RCKGenus Camptonectes 1\'Tn:E, 186:1
Camptonectes (s. s.) inexpectatus
JL,Lnll. new species
Plate 7. Figures 4, 5.

Description:-Shell medium to small
for genus, inequivalve. fairly inequilateral, nearly acline. not strongly inflated; antero-dorsal margin of main bodyslightly sinuated in each valve. while
postero-dorsal one is nearly straight:
umbo lying near mid-point of shelllength but at about two-thirds of hingeline from front, very slightly prosogyrous: apical angle probably about 115
degrees, though the value is with noaccuracy because of deformed material.
and may be more or less smaller in earlystage: auricles of two valves very unequal in size and shape: right anterior
one, i.e. byssal auricle. protruded forwards, of C!tlamys-type. about twice aslong as posterior one. defined from main
body by an auricular sulcus, deeply exJ1!easurement in mm.
~---~

~---

-~~-

--

cavated to form abyssal notch; ctenolia
distinct. five or more in number; left
anterior auricle very large, subtrigonalwith a slightly convex anterior margin,
truncated subvertically at corner, illdefined from main body: posterior auricleof each valve comparatively small, trigonal. truncated obliquely. well defined;surface of main body and auricles but
for byssal one ornamented with numerous fine flabellate characteristic Camptmzectes-st riations "·hich are neverpunctate, often bifurcated near ventral
periphery of left valve and strongly
bent up in both lateral areas: umbonal
region almost smooth; concentric lamellae somewhat regularly spaced but restricted to anterior part of each valve:on lett anterior auricle more than ten
erect subvertical lamellae countable already from early stage and abruptly
strengthened in middle stage: in laterstage some of them con! i nuous to anterior part of main body and fading
away downwards from inner side: byssal auricle marked with numerous concentric lamellae of growth. while they
are very weak on posterior one of eachvalve: resilifer triangular, completelyinternal: hinge and crural teeth absent:
musculature unknown.
LengthHeight12. 5+
27.5

Hl.5+
25.0

Thickness-----

Holotype (!\1M 2927) left ex. mould
Paratypc (MM 2928) right in. mould

Observation a11d Comparison :-Fourspecimens are more or less broken or
deformed. The holotype (Figs. -la-c)shows nearly complete antero-dorsal partof left valve. ill-defined anterior large
auricle, typical Camptouectes-striations
and prominent concentric lamellae. The
paratype (Fig. 5) reveals almost complete
rmtline of right valve, resilifer and dis-

2.5
·1. 0

tinct ctenolia. though more or less compressed in dorso-ventral direction. The
mode of surface-markings may be somewhat different between two valves. In
right valve CamPI01zectes·striations arecomparatively weak and increase their
number by insertion. but mainly bybifurcation in left valve.
Several species with Camptonectes·

360.

Pelecypods of the ivlizzmunza Jurassic

striations appeared already in the Permian of ~orth America (~EwELL. 1931)
and again in the Upper Triassic of Japan(:\AIC\ZAWA, 1952). but this genus
flourished most extensively in Aalenian
and later times. So far as I am aware.
there are few representati\·es of true
Camptonedes in the Lias (exclusive ofI\alenian) except for Camptonectes psilonoti STAESCIII' 11926) and Camptonecles
sp. in DECHr\SEALX fl936. p. 29, pl. 4, figs.
1-8). STAESCIIE and DEcHASEAtx considered that Pecten tmnctassimus QL: I·:Ns-rwT (185(): Tr:IHllJDI and PIETTE, 1868)from the Hettangian of Lorraine andsome other areas is intermediate bet ween C!tlamys and Camptonectes. but
Cox (1952) did not accept STAESCIII,·sphylogenetical concept from finely ribbed
Chlamys to Camptonectes during Liassic times. The present species is alower Liassic one belonging to Camptonectes <s. s.) defined by Cox (1%2),
and therefore suggests the presence ofa lineage independent from other pectinid
genera. which was originated probably
in such older species as mentioned above
and persistent throughout the Lias.
Another problem exists in the relationship between Camptonectes and Ento!ium.
Similarly tlabellate surface striae are
actually seen in several species of ento! iids, Pecten ISyncyr!onema) quotidimws
IIEAI.EY il908i for example. But suchforms have typical hinge-characters of
the Amusi idae, and the resemblance of
surface ornaments may be superficial.
This species is somewhat similar toCamptmzectrs lens ISowEI~BY) (1818), typeof the genus. The species and its close
allies flourished world-widely from
Aalenian to Oxfordian.
Though thesynonymy among them was discussed
repeatedly by manv authors. this species
differs from any hitherto described as
CamPtonectes lens. C. aurit us, C. arcual/Is

71

and C. aratus from Europe, India. andSouth America in having non-punctatesurface. more prominent concentriclamellae on large left anterior auricle
and anterior part of main body. In theserespects this may be more related toCamptonectes laminatus So\\·ERBY •1821)
from the Dogger of England. New Zealand and Argentina. According to ARKELL (1930b), C. laminatus is distinguishable from lens by the large left
anterior auricle which bears some ten
conspicuous raised verticle lamellae (12to 20 in full-grown specimens). This
species is. however, separable from lami11atus by the absence of strong concentrics on posterior auricle of each valve •and longer hinge line. Judging from
Sowi·:Jwy's and i\RI<ELr.·s figures. thatspecies has probably more slender outline with a smaller apical angle than
this. Camptonectes albertensis w-ARRE:-:(1932) from the Dogger of Alberta seems
also related to this in the outline andthe inequality of auricles of left valve.
The surface of the Canadian specimen
may be exfoliated as noted by himself,
and further comparison is difTicult. But
this is presumably different from it because neither radial nor concentric ornaments are discernible on left anteriorauricle of that species. Camptonectes
sp. in DEciJ.\SEAl'X (1936. Joe. cit.) fromthe Pliensbachian of Paris basin andCamptonectes psilonoli STAESCIIE :1926)
from the middle Lias of Swabia may heother intimate forms, but their concentric lamellae are probably much weaker.
This is easily distinguishable fromseveral Jurassic camptonectids describedin Japan (Kt~n·R,,, 1951: I-L'>YA~II, 1957c),
since those species have no surface
striae of Camptonectes-type. They shouldbe rather exciucled from Camptonectes.
though no suitable genus for them is
not yet found in any foreign literature.

ltaru H.4 YAM!

72

Occurrence :-Rare at Futamataji. Thisis the first pectinid from so-called"cyrcnoid beds'' of the Shizukawa
faunal province.

Family 'frigoniidae LAMARCKGenus Geratrigonia 1\onAY:\SIII.
in KoBAYASHI and 1\foRr. 195-l
Gemtrigonia !tosourensis (YoKoY.\~It\)
Plate 7. Figure~ 6-8.
1904, Trigonia lwsourensis Y OI\OYA:\IA, four.

Col!.. Sci. Imp. Uniz•. Tokyo, Vol. 18, Art.
6. p. 11. pl. 1. fig. 3.
1954. Geratrigonia hosourensis KoBAYASIII, in
KonAYASIII and !:!.loRI./apan.four. Ceo/.
Geogr .. Vol. 25. 1\"os. 3 4. p. 171. pl. 15.
figs. 1-2.
1954. Geratrigonia hosourensis \·ar. com•exa Ko·
HAYASHI in KOBAYASIII and l\foul,[bid.,
Vol. 25. Nos. 3-4. p. 112. pl. 16. figs.
9a-b.

1\Iany specimens are identical withthe holotype. Although all are more orless deformed, some observations on the
ontogeny. specific variation and ecologyof this species are added here.
In the largest specimen illustrated inFig. G, subconccntric costae on the disk
are somewhat effaced in the middle part.
rising up in lateral sides. On the posterior side of disk oblique costae arebluntly tuberculated. In another specimen in Fig. I, however, costae are nevereffaced. more or less V-shaped and fairly
irregular in antero-Yentral area. Some
small specimens as in Fig. 8. which represent the early stage of this species.
show regular concentric costae andsharp marginal carinae. and are very
similar to the specimen from Niranohama which KonAYASIII distinguishedas var. co1wexa from typical hosourensis.
These specimens were found at one
horizon in this area, and the differenceof costation should be at all attributed
to variation within one species. I\1ost
adult specimens belonging to my collection show more or less V-shapcd costae
on the disk, and such a tendency can beseen to some extent also in the holotype
and some other Niranohama specimens.
Geratrif!ollia is an aberrant genus, andits distribution is sti II restricted to theLias of Japan. Kon,\YASHI referred it
provisionally of the Trigoniinae (=Costatae). though the marginal carina isvery weak and the area very smooth forthe subfamily. l\ciost species of Jurassic
trigoniicls in Japan occur in more orless calcareous coarse sandstones whichwere formed presumably in certain littoral conditions and contain often crosslaminations indicating the agitation ofsea-water. But Geratrigonia alone occurs
chiefly in bituminous shales and finesandstones together with Modiolus. BakeN~Ilia,lsoguomon. Eomiodon. Yolwyamaina.

Tliracia and Cuspidaria (?) which are
hitherto called .. cyrenoid fauna". As
discussed before (HAYAMI, 1958b). theymust have been marine inhabitants instead of brackish ones. judging fromthe rock-facies and mode of fossil occurrence, however. such a bituminous
sedimentation must have undergone ina certain profound embayment where
sea-water was fairly stagnant and thephysical and chemical conditions arevery different from those of normal trigoniid-sandstones. The peculiar featureof this genus maY be attributed to theadaptation to such an environment.
Occurrence :-Common at Futamataji
and the south of Kusakariyama.

Family Cuspidariidae FisCIIER
Genus Cuspidaria 1'\ARno, 1840
( = Neaera

GRAY. 1833. non

Rniii:-;I·:.-u·-Dr-:svmDY. 1830)

360.

Pelecypods of the Mizzmuma jurassic

Cuspidaria (?) praenipponica
HAYA~ll. new species
Plate i. Figures 9-1:!.
1958. Cuspidaria (?) b sp. indet.. H.\YA~IL

Trans. Proc. Pal. Soc. fa pan, .\'. S .. So.
30, p. 198. pl. :!ii. figs. 20-:!1.

Description :-Shell small, slightly inequivalYe. highly inequilateral, rostratcd
and elongated posteriorly: test thin:antero·dorsal margin slightly convex.
passing gradually into venter, while
postero-dorsal one slightly sinuated. long,
turned abruptly into oblique siphonal
margin: ventral margin broadly arcuate
but fairly concave in front of posteriorcarination where ventral and siphonal
margins meet with an acute angle:
posterior carina sharp, nearly straight,
bordering posterior area which is very
flattened and occupies about a sixth ofwhole surface: posterior gaping. if present. very narrow: right valve having
a less inflated main body and more distinct ante-carina! sulcus than left:
seYeral conspicuous concentric wrinkles
present on surface in early stage but
probably much weakened later: ventral
and posterior areas marked only with
faint concentric Jines of growth: hingeteeth and chondrophore unknown, pro·bably undeYeloped.
Length

I Ieight

Thickness

Holotype (!Mi\'1 2932) left in. mould

li.:1

1~.0

-1. 0

Paratype (l\IM 2935) right valve

11. 0

6.5

2.0

Jfeasurement ill mm.

Obserration and Comparison :-All houghmost specimens are strongly deformed.
the original outline may be best pre·scryed in the holotype (Fig. 9\ This
species is certainly conspecific with
Cuspidaria (?) b sp. from Niranohama.
The two i\iranohama specimens are probably young shells, and quite similar to
many small specimens from this area inoutline and umbonal concentrics. Cuspidaria (?)asp. in H.\YA\11 (1958d, p. 197.
pl. 28, figs. 16-1 9) from the Domerio·
Toarcian of the Kuruma group is also
very similar to this. But I presume
that the two forms arc specitically dif·ferent. judging from the subverticalsiphonal margin. less prominent posteriorcarina and absence of concentric ribs inthat form. These two forms are, ofcourse. not typical cuspidariids. andtheir taxonomic positions cannot be
decided because of ignorance of internal
structure. Several similar species appeared in the Upper Triassic and Jura-ssic of Soul heastern Asia. "Cuspidaria··
ayabntsis NAJ(AZAWA (1956) from theCarnic of .Japan. CusPidaria sp. in HEALEY(1908) from the l~hactic (or Noric) of
Burma. Cuspidaria latecaudata S..wRJ;-o:(1941) from the Noric (?) of Annam and
Neaera sambasmza VocEL l1900) from theJurassic of Borneo are certainly congeneric with this. As noted on .Kiranohama specimens before. this is probably
an ally to N. sambasana, but differs fromit in the weaker ante-carina] sulcus andnot sinuated pre-umbonal margin. Cus·
pidaria /aler:rmdala is quite similar tothis in general outline and strength ofposterior cari nat ion. Its further closecomparison with this is impossible atpresent, because both species are represented by more or less strongly deformed specimens.
Occurrence :-Common in black shales
at Futamataji and the south of Kusakariyama.

7-lltaru HAYAMIFamily Burmesiidae HEALEY
Genus Hunnesia HEALEY, 1908

Burmesia japonica HA YAi\11, ne\Y species
Plate 7. Figures 13-18.

Description: -Shell small for genus.
equivalve, subequilateral, elongate-oval,
not strongly inflated. not carinated. moreor less gaping antero-ventrally and posteriorly: test thin: ventral margin
broadly arcuate but abruptly bent up
laterally, serrated at antero-ventral gaping: umbo suborthogyrous. submesial.
slightly rising above hinge-line: surface

marked with about 35 narrow but elevated radial plicae except for posteriorarea: radials most dense in middle. becoming gradually sparse towards bothsides, sometimes increasing their number by insertion: concentrics somewhat
Iamel!ose, fairly strong and widely
spaced in posterior area where radials
are absent or much weakened: in anterior part intervals of radials excaYatedroundly. marked with numerous concentric lamellae: sometimes a narrowsmooth belt appears in central part :hinge apparently edentulous; chondrophore and ligament unknown.

Jl[Msuremenl in mm.

Lengthllolot ypc (MM 2936) left ex. mould
Paratypc (Mivl 2937) right. in. mould:23.0

Observation and Compm·ison :-Among
many deformed specimens. the holotype
and paratype arc best preserved. showing probably original outline and surface-making of this species. The dissimilarity among illustrated specimens
is principally due to secondary deformation. The holotype is slightly broken
in antero-dorsal part. but the anteroventral gaping is presumable fromgrowth-lines.
Genus Burmesia was originally founded on two species from the Rhaetic (orN'oric) Napeng beds in Upper Burma.
But the two seem fairly different in themode of costation: more precisely. Bur·
mesia lira/a has several oblique costae
on the anterior area which remind at
a glance one of those of Goniomya. while
in Burmesia /aioucllii the anterior area
is marked with simple fine radials. The
type-species of Bwmesia was not selected by IIEALI·:Y herself. and DIENER's
designation ( 1923) on B. latouclzei (? mis-

HeightThickness

11. 5

3.5

8.5

3. O+

spelling of latouchii) is probably the
first. Anyhow, I do not consider herethat such oblique costal ion is a diagnostic
character of the genus. The taxonomic
position of Burmesia has not yet been
settled. HEALE\' proposed the Burmesiidae, but WA:-;:'\ER and Ki'\IPSciiEER (1951)
referred it to the Anatinidae (=Laternulidae).
This species resembles closely B.
latouchii in the general outline and distribution of radials. but the shell ismuch smaller and more elongated horizontally than the Napeng species. B.
lirata in MA:-.:SL'Y (1921) and P,\TTE (1922)
from the Noric of Indochina shows similar outline, but the radial plicae of thisspecies are more densely spaced on the
middle shell-surface. Burmesia praecur·
sor KRu~wECK (1913) and B. tceberi WA:-;NER and K:-.:IPSCIIEER (1951) from the
Noric of Buru and lVIisol have obliqueribs in anterior part and arc more similar to H lirata from Napeng than to36 0.

Pelecypods of the ]VJ.izunuma jurassic

this species. Bunnesia? posteroradiata
Cox (192,1) from the Carnic of Jordan
Valley seems not close to this. since its
anterior half of shell is almost smooth.
lacking any radial ornament.
Neoburmesia iu·akiensis YAnE and S:\TO(1942) from the Upper Jurassic of Soma
area in Xorth Japan has somewhat similar ornaments to Burmesia. But is isvery different from this and Napeng
species in the large and inliated shell,
excavated ventral margin. very anterior
umbo and Area-like carinated outline.
though it cannot be a taxodont judging
from the thin test in some topotype
specimens. Plwladomya SowEtWY !1823)
has sometimes similar to Burmesia, but
the latter is distinct from the former inhaving a chondrophore and characteristic
radials which are densely spaced especially in the middle part of shell andbecome gradually sparse and obscure
towards both sides. 11fyoplzo!as acuticostala var. nana DrKYII.LE (1907) in LtsSAJOL·s(1923) from the Bathonian issomewhat similar to this mode of costation. but the radials are more sparsethan in this species.
Occurrence :--Common at Futamataji.
This species is found in some blackshales about 30 meters below the Geratrigonia !zosoureusis beds. It is the first
Liassic species of Burmesia. Several
fragmental specimens were procured
also at Niranohama of Shizukawa area.

Heferences
ARt: ELL. W. J (1930a), The generic Po:oition
and Phylogeny of some Jurassic Arcidae.
Geol. 1Hag.. Vol. 67,- - (1930b. 1933). A l\·Ionograph of British
Corallian Lamcllibranchia. Palaeontogr.
Soc. London.
BRA:'\SO:". C. C. (19"12). Parallelodon, Grammatodon and Cosmelodon. four. Pal., Vol.

75

16.

Cox. L. R. (1924). A Triassic Fauna fromthe Jordan Vallcv. Ann. ,1[ag. Nat. Hist ..
Ser. 9. Vol. 14.
- · (1952). The Jurassic Lamellibranch Fauna of Cutch (Kuchh). Palaeont. Indica,Ser. 9. Vol. 3. Pt. 4.
Dr.cH.\SEAUX, C. (1936),
Pectinides jurassi·
ques de I'Est du Bassin de Paris. Atm.
Pali!ont .. Tom. 25.
DtE:'\ER. C. (1923). Lamellibranchiate triadica
I I. Fossilium Catalogus. 1..!lnimalia, Pars
19.
Dot·\-I!.LE. H. (1907). Les Lamcllibranchet;cavicoles. Bull. Soc. gt'ol. France. Sir. 4.
Tom. 7.
GoTTSCHE. C. (1861). Ueber jurassische Ver·steinerungen aus der argentinischen Cordillerc Palaeontogr .. Supple. 3. Lief 2, Abt.
3l-IE-\ LEY. 1vl (1908), The Fauna of the Napeng
Beds or the Rhaetic Beds of Upper
Burma. Palaeont. Indica, N. S.. Vol. 2,
Jlfem. No. 4.
1-IAY,\~11. I. (1957a). Liassic Bakerellia in Japan. japan. four. Geol. Geogr .. Vol. 28.
Nos. 1-3.
- - (1957b), Liassic GenJi!lia and Jsognomon
in Japan. Ibid., foe. cit- - (1957c). Liassic Chtamys. "Camptonectes".:nd other Pectinids from the Kururna
Group in Central Japan. Trans. Proc. Pal.
Soc. Japan . .V. S .. No. 28.
- - (1958a). Liassic Volsella. Mytilus andsome other Dysodont Species in Japan.
Ibid., N. S .. 1Yo. 29.
- - (1958b). A Review on the Liassic socalled "Cyrenoids" in Japan. japan. four.
Geo!. Geogr .. Vol. 29. Nos. 1-3.
- - (1958c). Some Hettangian Pelecypods
from the .. Trigonia-sandstone '' of the
Shizukawa Group in I\orth Japan. Ibid.,foe. cit.

- - (1958d), Supplementary Descriptions of
the Liassic Pelecypods from the Kuruma
and Shizukawa Groups in Japan. Trans.
Proc. Pal. Soc. Japan. N.S., Ao. SO.
I;-;M, Y. and TAKAHASHI, N. (1940). On the
Geology of the Southmost Kitakarni!'v!ountainland. Cont .. lnst. Geo/. Pal.. Toholm

76

Itaru liAYAMI

Imp. Unit• .. No. 33. (in Japanese).
KnHm.\, T. (1951). Some Pectinids and a
Limid from the Jurassic Torinosu Groupin Japan.]our. Pac. Sci .. Unit!. Tokyo, Sec.
2, Vol. 7. Pts. 6-10.
KoBAYASHI. T. (1948). Tectonic Geology ofJapanese Islands. Tollyo. (in japanese).
--,KoNISHI, K.. S.\TO. T.. HAY.-\~11. I. and
ToKUYA:-.IA, A. (1957). On the Lower
Jurassic Kuruma Group. ]our. Geol. Soc.
japan. Vol. 63. No. 738. (in japanese).
- - and :\loRI, K. (195·1). Studies on thejurassic Trigonians in japan. Part 2.
Pmsogyrotrigonia and the Trigoniinae.
japan. ]our. Geol. Geogr., Vol. 25. Nos.
3-4.
KRUMBECE, L. (1913), Obcre Trias von Buruund lVIisol. Palaeontogr . .Supple. 4. Lief 2.
LISSAJOUs, M. (1923). Etude sur Ia Faune
du Bathonicn des Environs de Macon.

Tra1!. Labor. Geol. Fac. Sci. Lyon. Fasc. :;,ilNm. 3.
.1\I.'\KSV>', I-I. (1914). Description d'Especes
nouvelles des Terrains paleozoiques ettriasiqucs du Tonkin. Mhn. Serv. geol.
lndochine. Vol. 3, Fasc. 2.
- - (1921). Nouvelle Contribution!'Etudedes Faunes des Terrains gothlandiens.
devoniens et rhctiens de Ia Region de
Ia Basse Riviere noire. Ibid .. Vol. 8. Fasc.

a1.

NAKAZA\\'A, K. (1952). A Study on the Pelecypod-Fauna of the Upper Triassic
Nabae Group in the ~orthem Part ofExplanation of Plate 7
Parallelodou niranolumu:msis I·L\ Y "\ ~~~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . Page 68
Fig. 1. Right internal mould (MM ~92-!), xl. Loc. Futamatji.
Fig. ~- Clay cast of left external mould (MM 2925) x2. Loc. ditto.
Baket.oel/ia cf. trigona (YoKOL\:-.IA) .................................................... Page 69
Fig. 3. Left internal mould (:\f;\1 292G) x2/3. Loc. north of .Mizunuma.
Camptonectes (s.s.) inexpectatus I-IAYA~II. new species.
. .... Page 70
Fig. cia. Left external mould (MM 2927). holotype, x 1. Loc. Futamataji.
Fig. 4b. The same specimen. x2.5.
Fig. 4c. Clay cast of the same specimen, x2.5.
Fig. 5. Right internal mould (MI.\1 2928). paratype. xl. Loc. ditto.
Geratrigonia hosourensis (YoKoYA:O.IA) ........................ _........................ Page 72
Fig. 6. Clay cast of right external mould (1\fM 2929) x l. Loc. ditto.
Fig. 7. Clay cast of right external mould (MM 29:30) x 1. Loc. south of Kusakariyama.
Fig. 8. Clay cast of left external mould (MM 2931) x 2. Loc. ditto.
Cuspidaria (.') praenippmtica H.·\Y.-\~11. new species ................................... Page 73
Fig. 9. Left internal mould (1\IM 2932). holotype, x2. Loc. Futamataji.
Fig. 10. Clay cast of left external mould (MM 2933) x2. Loc. ditto.
Fig. 11. Left internal mould (MM 293-!) x2. Loc. ditto.
Fig. 12. Right valve (MM 2935). paratype. x2. Loc. ditto.
Burmesia japonica H:\YA~H. new species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .... Page 7-1
Fig. 13a. Left external mould (MM 2936). holotype. x2. Loc. ditto.
Fig. 13b. Clay cast of the same specimen. X 2.
Fig. 13c. Clay cast of the same specimen, X l.
Fig. VJ. Right internal mould (Ml\1 2937). paratype. x2. Loc. ditto.
Fig. 15. Clay cast of right external mould (MM 2938), x2. Loc. ditto.
Fig. 16. C!ay cast of left external mould (MM 2939), paratype. Loc. ditto.
Fig. 17. Clay cast of right external mould (M:\1 2940) x2. Loc. ditto.
Fig. 18. Clay cast of left external mould (:\E\-1 2941) x2. Loc. ditto.

All specimens illustrated here are kept in the Geological Institute. University of Tokyo.

HAYAMI:

Pelecypods of the Mizunuma Jurassic

Plate 7

1

4b

12

13c

360.

Pelecypods of the Mizzmuma Jurassic

Kyoto Prefecture. Japan. Part l. Mem.
Col/. Sci .. Unit•. Kyoto. Ser. B, Vol. 20, .Vo.
2.
(1956). Op. cit. Part I. Ibid .. Ser. B. Vol.
23, No.2.
NEWELL, N.D. (1938). Late Palaeo;wic Pele·
cypods. Kansas Ceo/. Surv., Vol. 10.
0:-.;L'KI, Y. (1956), Explanatorr Text of theGeological Map of I wate Prefecture, vol.
2. lu:ate Pref. (in Japanese).
PATTE, E. (1922). Etudes de quelques Fossiles
paleozoiques et mcsozoiqm:s recuei II is
en Indochine et au Yun-nan. Jlhn. Sr>rz•.

-

giol. Indochina. Vol. 9. Fasc. 1.
Qut:?>:STEDT. F. A. (1858). Der Jura. Tiibin!Jt!ll.
S,\L'RJ:>:, E. (1941). Lamellibranches duTrias superieur de Hoa-Huynh (Sud·Annam). Bull. SenJ. gcol. lntloc!tina, Vol.
26. Fasc. 3.
SowERIIY. ]. (1818. 1821). The l\lineral Con·
chology of Great Britain. Vols. 2 and 3.
London.
ST..\ESCJJE, K. (1926). Die Pectiniden des Sch·wabischen Jura. Ceo/. Pal. Abha11dl., N.
F.

Btl. 15.

TERQliE~I.

77

0. and PIETTE, E (1868). Le Lias
inferieur de I'Est de Ia Fran(.;c comprenant Ia Meurthe. Ia l\loselle. le Grand·
Duchc de Luxembourg. Ia Belgique et Ia
Meuse. iW:m. Soc. gi:ol. France, Ser. 2.
Tom. 8.
VoGEL, F. (1900), Neue l\lollsken aus dem
Jura von Borneo. Samml. Ceo/. Reiclts·!\Jus. Leiden. Ser. 1. Bel. 6. He/1 2.
WA:":>:ER,]. and K:-~JPSCHEER. II. C. G. (1951),
Beitriige zur Palaontologie des Ostindi·schen Archipcls. XX. Neue Ver:;teiner·
ungen aus den norischcn .iVucu/a-Mergeln
Yon Misol. Neues ]a!Jrb. f Ceo/. 11. Pal..
Abh., Bd. 94.
WARRr·:N, I'. S. (1932). A nt:w Pelecypod Fauna from the Fernie Formation. Alberta.
Trans. Roy. Soc. Canada. Ser. 4, Vol. 26.
Y t\JJE. H. and S,\To, S. (19·1:!). A new Bivalve
from the Jurassic Torinosu Series of the
Abu kuma Mountainland. Proc. Imp. Acad.
Tokyo, Vol. 18. ~vo. 5.
YoiWYA~IA. 1\I. (1904). On some Jurassic Fossils from Rikuzen. four. Colt. Sci, Imp.
Uuiv. Tokyo, Fat. 18, Art. 6.

Trans. Proc. Palaeont. Soc. Japan. N. S .. No. 34. p. 78,_ June 15, 1958

SHORT NOTES:3.

A~ADDITIONAL NOTE ON THE LIASSIC.. CYRENOIDS ·· IN JAPANIT ARU I-I AYAl\U
Geological Institute. Univ~:rsity of Tokyo

Soon after my reYision (1958) had been
published, 1 read CAsEY's (1955) of Neomiodonticlae. nov. His new family. which
includes Romiodon Cox. 1935, My rene
CAsEY, 1955. Cyrenopsis ETHERIDGE, l!l02
and Jlfusculiopsis l\1."-cNEIL, 1939 besides
Neomiodon Fiscii"R. 1887 (=Protomiodon
AxoERsn:-.- and Cox, HJ.18). and may be
the forerunner of the Corbiculidae. Accepting his opinion, I transfer Eomiodon
lmmlal us. E. uu/garis. E. sp., E. (?) ![iganteus and E.(?) sp. from the Arcticidae
to the :\'eomiodontidae. In the hinge
structure E. lmwlatus (YoKOYAl\1.\)(Text-figs.) from lower Lias is quite
similar to Eomiodon czmea/us (SowEIWY)(CAsEY. p. ~10, figs. 1-3) but for theworse-defined cardinal tooth 5b fromnymph and developed lateral Pili. Other
features are diagnostic of the genus.
Liassic Cre11otrapezium kurumense H,\\',\·:-.11 is allied to Neomiodon as well as Eotrapezium. l n the carinated trigonal outline and position of cardinals it seems
more similar to Eotrapezium but toNeomiodou in the lateral teeth. Com·
pared with CAsEY's hinge of Neomiodrm(p. 210. fig. 7), the inner lateral teeth
are more distinctly crenulated. In thisrespect the Japanese species is closer
to J\1yrmw than Neomiodou, but the pos-terior laterals are double in the rightvalve and single in the left as in Neo·
miodon (single in the right and double
in the left in Myrene). It is presumablytransitional between Eotrapezium andNeomiodon (or 11fyrene) and located also
in the Neomiodontidae. It bears impor·tancc on phylogeny that the family iswell represented already in the Lias ofJapan.

1.

Tv:-:t-figs.
R:

L:

Hinge structures of F.omiodon
llmulatus (Ym; OYAMA)
rvstored from a right internal mould(MM 2837) :-, l.
restored from a left internal mould(!\I~I 28·11) xl. 2.

Heferenees
CASI"·· R. (1955). The Neomiodontidae. a
new Family of the Arcticacca (Pelccypoda). Proc. J1falac. S(lc. London, Vol. 31,
Pts. 5. 6.
HAY .-\~11. I. (1958), A Review on the so-call·
cd Liassic "Cyrenoi<ls" in Japan. JaPan.
Jour. Geol. Geogr., Vol. 29, Nos. 1-3.

78

Trans. Proc. Palaeont. Soc. Japan, ~- S., No. 34, pp. 79-85. pl. 8. june 15. 1959

:1Gl.

NOTE ON SOl\IE PERMIAN CORALS FROM FUKUJI.
HIDA MASSIF'. CENTRAL JAPA~*HISAYOSHI IGO

Institute of Geology and Mineralogy. Tokyo Uninrsity of Education
nUiiirlJ.iil!n',iJtl!@f=:~H~HIIJ.f.ljj ftE:-: "? •. '-r: 1RWilJ:II!!ffi\.iil!f;f.t.i'il: 'jEJ! T ~ -:::"'t;f:J.I<~n:o­lf/1 O'l!illfi\itJ· ~ ~IJ! lA.:lll!lfNifto£l:>? 't':. 3 Yfr'fifi • 1 tli!Jfifll! · 2 *~.fif!~~l1ii: L. 'Jf:rt tJ~ri-/fiL'l'·Jllll•~~0ln·~t~•=n*~~~~~~-l~-me~~of the Osobudani conglomerate at thetype locality.
II ere I thank Professors Haruyoshi
Ft·JI:\IOTO and \Yataru H.\sHJ:-.!OTo of theInstitute of Geology and Mineralogy,
Tokyo University of Education for theirkind guidance throughout the present
study. Acknowledgements are due toProfessor Kotora HATM of the Depart·
ment of Geology, Faculty of Education.
Tohoku University for his encourage·
ment, and Professor :vrasao 1\-I,:-:ATO of
the Institute of Geology and Mineralogy.
Hokkaido University for his advice re·ceived in 1!153. and l\Ir. Tadao KAMEl of
the Institute of Geology. Shinshu Univ·
ersity. for his cooperation in the field.
Thanks are also due to the ?vlinistry of
Education. Japanese Government and the
Asahi Press for grants from their
Scientific Expenditure Funds awarded
to Professor II. Ft7JI:o.IoTo.

Introduction and Acknowledgements

In this paper several corals collectedfrom the Permian Mizuyagadani andSorayama formations developed at Fuku·
ji, Kamitakara Village. Yoshiki County,
Gifu Prefecture (lG6 19S7) are described
and their stratigraphic significance is dis·cussed. The Lower Permian l'viizuyagadaniformation is roughly subdivided into
the lower or Pseudosclumgerina-limestone
and upper or clastic sediments. The
next younger Sorayama formation con·sists of a remarkable basal conglomerate(Osobudani conglomerate) conformably
overlain with agglomeratic schalstein or
volcanic conglomerate (Sorayama con·glomerate and schalstein).
The corals treated herein are Soch·
kineophyllum japoninmz k6. n. sp. and S.
japonicum pauciseptalum ko. n. subsp.
from the calcareous tuff bed developedin the l\fizuyagadani valley: Ammufo·
phy/lum sp. from the thin conglomerateor conglomeratic shale of the middle
part of the lVIizuyagadani formation
dewloped at the junction of the Taka·dani and Osobudani valleys ; Iranophvf.
fum I unicafum leo. n. sp.. !Veutzeteila
osobudaniensi.~ leo. n. sp., and Lonsda!eia·
stmea? sp. from the limestone pebbles

Stratigraphical Note

The two new forms of Sochl~ineop!zyl·
fum were collected from a green andred calcareous tuff bed in the lower
part of the Mizuyagadani formation.
which directly covers the Pseudo.~ch·zmgerina·l imestone. This about 10 meters
thick bed at the type section whichyielded abundant specimens of brach·* Recei\·ed Sept. 25. 1958. read Feb. 2, 1958.
79

so

Jlisayaslzi [G(;iopods, corals, bryozoans, and fragmentsof crinoid stems, graded upwards into
tuffaceous shale. Recently K..\~IEI (1951)
described f1/erophyl/um hideuse 1\,,~.JEI
and Huangia mizuyagadaniensis 1\. A ~• E 1
from this heel.* He a!so reported on theoccurrence of Squamularia asiatica C11.\0,
Spiriferella cfr. salteri Tscm::n:--;yscJIEW
and other unidentified brachiopods. 1\Ar-.IEI insisted that the coral-brachiopods
faunule belongs to the Zone of Parafusulina and, therefore, is Artinskian inage. However, I consider that the larger
part of the l'vlizuyagadani formation may
represent the Zone of Pseudosclucagerinaand is, therefore. Sakmarian in age fromthe following facts.
Soclz!?ineoPhy!lum japonicum ld3. n. sp.,and S. japonicum pauciseptatum leo, n.
subsp. from the calcareous tuff bed resemble S. arliense ISosJJKI:-.A) and S. tenuiseptatum (SosHKJ:--;,,) from the Artinskian of the west slope of the northern
Urals. Soviet Russia, hut our forms are
specifically distinct from the latters.
Recently I found Pseudofusulina vulgaris(ScHELLWJEK) and other related thickwalled-type Pseudofusulina from thematrix of the conglomerate or conglomeratic shale lying slightly above the
Sochkineoplzy/lum-bed.
Although rare
they are favorably preserved in tine
grained shale and based upon the modeof occurrence, these fusulinids may becontemporaneous or penecontemporaneouswith the deposition of this bed. The
same fusulinids are common in the Nyukawa group which is widely developedin the south of the present district andthey are frequently associated with
abundant Pseudosc/ucagerina. This faunal
relationship is known from other localities of the japanese Lower Permian* It is doubtful that the latter species wasderived from this bed.

rocks. Amandophyllum sp. also occurs
from the limestone breccia of the same
horizon. This unnamed species is somewhat related to ilmandophyl!um camicum(HEI~ITSCH) which was reported from theUpper Auernig series (Cpper Kalkreichgroup) in the Carnic Alps, Austria. The
brachiopods listed by KA:-.mT are rather
long range types and are not restricted
to the Artinskian.
On the other hand the corals fromthe limestone pebbles of the Osobudani
conglomerate indicate the late Early
Permian or slightly younger age than
the 1\iizuyagadani. Irmzopltyllum tunicatum Ico, n. sp. resembles [. sp/endens
DoL·cLAs from the Lo\\·er Permian ofTapi leh Valley. Darrell Dazen. Southwest
Iran. In the present area it is associated with Pseudofusulina dujJ/itlzecata
P. spp .. Nmzkine!la kotakie11sis IFL·JJ~IoToand K ..\ \L\DA). N. lwzcadai (lt;6) and othersrlcA 195Ga. h).
Although !Ventzelella
osol111daniensis Jd), n. sp. and Lonsda!eiastraea ? sp. are not sufficient for determination of the geological age they may
represent a slightly higher position than
Iranophyilum. These corals were apparently derived from the I\lizuyagadaniformation before the deposition of the
Osohudani conglomerate. It should bemade clear that no fossils have beencollected which definitely indicate theexistence of the Zone of Parafusu/ina
from the pebbles of the Osobudani. Un·
fortunately the age of neither the Sorayama formation nor the Osobudani conglomerate can be determined with accuracy, hut there remains a great probability that either the Zone of Parafusulina is represented in only the uppermost part of the i'vhzuyagadani andwas partly denudated during the preOsobudani hiatus or that the Sorayama
corresponds to the Zone of Pamfusulina.

Teo.

361.

81

Permian Corals from Hida Massif

Description of Species

Family Polycoeliidae RoniEI~. 1883
Subfamily Polycoeliinac RoEMER. 1883
Genus Sochl?ineophyllum GRAB,\"· 1928
Sochkineophyllum japonicum lc1\ n. sp.
Plate 8. figures 4a, b.

Corallum solitary: corallitc small.
slightly curved cylindrical with turbinate proximal part. Diameter of corallite 13 mm and length about 40 mm at
maturity. Outer wall rather thick andexternally with well de,·eloped concen1ric rings. septal grooves less distinct.
l\Iajor septa ~6 in number at diameterof 13 mm. and ~2 at 9 mm. The~· arearranged more or less pinnately, considerably thickened by stereop!asmic
deposits. and remarkably accelerated incounter quadrants.
In adult stage.
counter and t\VO alar septa very o~t­standing and extend to near center.
Cardinal septum rather long in prcma1ure stage but considerably absorbed atmaturity. Counter septum straight.
slightly S\Yollen and somewhat pendantshape. In cardinal quadrants two pairsof distinct metasepta developed and almost as thick as alar septa. Several
major septa in counter quadrants flexible ncar axial edges. Alar septa out·
standing throughout growth. l\linor
septa well developed but short and restricted to peripheral part. In young
stage they appear as counter quadrants.
In longitudinal section subhorizontal
or undulated and thin tabulae rather
coarsely spaced and cross corallites. 1\odissepiments recognized.
Remarks :-This new species moreclosely resembles Sochllineophyl!mn artiense iSosHr;r;--.;A) than any other described species. However. it differs fromthe latter in the smaller corallite atmaturity. insertion of metasepta andless distinct cardinal fossula. It is easily
distinguishable from S. tenuiseptatum(Sosiii-:It"A) by the more distinct thickening of the major septa near the axialedges and well deyeJoped tertiary septa
in the Fukuji species.
Occurrena :-The \1izuyagadani ValIcy: middle part of the lVIizuyagadaniformation.
Geological age :-Earl~.. Permian. theZone of Psr'udoschtcagerina.
Reg. nos.* 21003 (Holotype). 21013(Para type).
Sochllineopilyllum japonic 11111
pauciseptatum IG6, n. subsp.
Plate 8. figures 5a. b. <i.

Corallum solitary: corallite small.
cylindrical "·ith turbinate proximal end.
about 60 mm and 11 mm in length anddiameter. respectiYely. External wall
thick and concentric rings well observedat surface of cora IIi te.
First and second order septa '.!.7 in
number in full growth and more or lesspinnatelv arranged. Counter and alarsepta very outstanding, long. thick andextending to near center. In counter
quadrants two or three longer septa
extendieg to near center. In premature
stage some of them directly united eachother. Cardinal septum shorter thanother major septa. In counter quadrants septa more accelerated than cardinal ones. Third order septa rarely recognized but Yery short and almost
rudimentary.
In longitudinal section. thin tabulae
completely cross entire corallite. rather* l~egister number of specimen oresen·ed
in the collection of the Instituteof Gco!Og\'

and Mineralogy. Faculty of Science. Tok\'O
Uni\·ersity of Education.
.

llisayoslzi Ic6

82

coarsely spaced. six in a distance of
10 mm, horizontal in median part, gently
uparching or downwards at periphery.
Remarks:-This new subspecies is distinguished from S. japonicum (s. s.) by
the well developed third order of septa
and thicker major septa. It closely resembles Socl!l?ineop/iyllum art iense (SosllKI:-;A), but the former possesses a smaller
diameter of corallite. almost rudimentary third order septa. and less convex
tabulae. It differs from S. tenuiseptatum(SosHI\1:-<A) mainly by the distinct pendant-shape of the protosepta and more
crowded tabulae. Also the present form
recalls Plerophyllum hidense K.,~l EI in
many respects, however, his material isunfavorably preserved, thus I withholdcomparison with it.
Occurrence and geo!ogiwl age:- Thesame as the preceding one.
Reg. nos. 20500 (Holotype), 20501 (Paratype).

well circumscribed area and consists of
septal lamellae and axial tabellae, bothof which considerably tllickend by secondary deposits:
Dissepiments arranged concentricallybut partially herringbone pattern.
Remarlls :-Onlyonefragmentary
specimen was obtained and its detailed
characters are unobservable. Although
it is evident that the present specimen
is close to the genus A.mandopltyl/um
H~:Rnsc11 and resembles A. camicum(lh:rnTscll) in some respects. its naming
is reserved until better materials accumulate.
Occurrence :-Conglomeratic shale of
the !vlizuyagadani formation at the junction of the Takaclani and Osobuclani
Valleys.
Geological age :-Early Permian; Zoneof Pseudosduoagerina.
Reg. no. 20230.
Family Lonsdaleiidae CHAP:\1.\~. 1893

Family Aulophyllidae DvBO\\'SKI, 1873

Subfamily Waagenophyllinae

Subfamily Aulophyllinae DvBowsr.;J. 1873

WA:-.:G, 1950

Genus Jlmandophy!lum IlERITscH, 1941

Genus [rauop!tyllum DocGLAS, 1936

Amandophyl/um sp. indet.

lranophyllum t unicat um leo, n. sp.

Plate 8. figures Ia. b.

Plate 8, figures la. b: text· figure I.

Corallum solitary, corallite small. Diameter of corallite 12 mm to 15 mm inmature stage. External character unobservable.
Epithec.:a almost erroded
av.·ay during fossilization. thus detailed
characters remain unknown.
Septa consists of two orders of major
and minor. Major septa 2fi in number,
extend to central column. thickened bysecondary deposits, and almost straight.
l\linor septa alternate with the former,
short. about 1/3 as long as major ones
and restricted in peripheral region.
Central column occupies rather wide

Corallum solitary, corallite cylindricaland moderate in size. External characters unobservable. Epitheca very thin.
Diameter of corallite 20 to 17 mm at
maturity.
Septa numerous. those of first order
30 in number, long. extending to near
center but not united with columella,strongly thickened by stereoplasmic deposits in intrathecal region, partiallydiverging. thin in proximal part. Second
order septa more numerous but shorter
than those of first order, more than 1/3
as long as the former and coalesced

361.

Permian Corals from llida Massif

with each other in intrathecal region.
Third order septa shorter and restricted
in periphery. fewer than those of second
order. and about 1/2 length of the latter- Fourth order septa very short.
equal in lengh, and restricted to very
narrow marginal area. All septa carinated and somewhat zig-zag in dissepimental
area. Columella occupies about 1/5 thediameter of corallite. consists of medianplate. radiating septal lamellae. andsteeply arched axial tabellae. Dissepimental area wide and arranged concentrically.
In longitudinal section dissepiments
rather irregular in size and their convex
sides faced upwards and i nwarcls.

former has we II developed fourth orderof septa, carinated septa more complicated columella and steeply arched axial
tabellae and the septa are more strongly
thickened by stereoplasmic deposits inthe middle and distal parts. It also resembles I. carcinophy/loides DoL'GLAS
from the same locality and !. Permicuml\J,x,\To from the Sakamotozawa seriesof the Kitakami \[assif. northeasternjapan. but the present form is distinguishable from the latters in the possession of a greater number of ordersof septa.
Occurrence :-From the pebbles of theOsobuclani conglomerate. the Osobudani
Valley, associated with Pseudofusulina
dup!itllecata leo, P. spp., Nankinella kotakieJJsis (FUJI)<.IOTO and K.\\YAD.\J and N.
kmcadai (lr.l)).
Geological age:-- Late Early Permian:
Zone of Pseudosclztcagerina.
Reg. no. ~1015 (Holotype).
Genus Wentzele!la GR.\B.\1. 1932

IVentzelel/a osobudrmiensis ko. n. sp.
Plate S, figure 3.

Tcxt·figurc 1.

Remarks :-lranophyllum tunicatum ko,
n. sp. resembles I. sp!eudens Dou(;J.As
from the Lower Permian of the Tap i leh
Valley, Darreh Dazden, Southwest Iran
(Persia) in many respects. However. theCorallum massive. cerioid: coral!ites
rat her large, hexagonal. pentagonal oroctagonal in shape at maturity. Diameter of corallite about 7 to 1~ mm.
External wall originally thin but moreor less thickened by stereoplasmic deposits and straight or zig-zag.
First order septa long, ~0 to 24 in
number, reach to near center but not
jointed \Vith columella. but in young
stage one septum (counter?) is jointed
with median plate. gradually thickened
intrathecal area and thining towards
distaly, second order septa about 1/2 to
31'1 as long as those of the first orderand more numerous. Third order septa
very short, thickened by stereoplasmic

84

I-Iisayoshi /Go

deposits near wall and restricted tomarginal part of corallite. Fourth ordersepta frequently appear but not throughout. and very short. Columella notlarge. oval in transverse section, wellcircumscribed and consists of thickmedian plate. three to five rows of axial
tabellae. and few septal lamellae. and distinct median plate is jointed with one
major septum in early stage.
Dissepiments arranged concentrically,in rare cases they form interrupted
septa where major ones are discon·tinuous.
Remarlls :-The present new form isclosely related to rv. szecliurmellsis H L';\ i'o'G
in many respects. but the Fukuji species
has a distinct median plate in the columella. Also it differs from W. hilakamiensis YAB:o: and l'vlJ;.;.,,.o by the samecharacter and shorter fourth order septa.
The Fukuji sepccies is distinguishable
from TV. sel?ii 1\IJc;ATO in possessing
quaternary septa and a median plate.
Occurrence:- The same as the preceding species.
Geological age:·-· Early Middle Permian?
or late Early Permian.
Reg. no. 20·1n 1Ilolotype).

Genus Lo11sdaleiastraea GERTH, 1921

Lonsdaleiastraea ? sp.
Plate 8. figure 2.

Corallum massive. corallite cerioid
partly thamnasteroid and aphroid, subtel ragonal or pentagonal in shape. andabout five to eight in diameter.
Major septa 17 to 18 in number. long,reach to near center. some of them continue with columella. :'Viinor septa alternate with major ones. shorter. andabout 2/3 to 3/5 length of major, thirdorder septa appear. but thinner. fewer
and almost rudimentary. These septa
are interrupted by vesicular dissepiments, slightly zig-zag or straight. Co·
lumellar structure obscure owing tostrong stereoplasmic deposits. Dissepiments about 1/2 as wide as diameter ofcorallite. and arranged concentrically or
partially lonsdaleoids.
Remarks :-The species is referred to
Lousdaleiastraea with some reservations.
TlH' type species of this genus L. z·inas·
sai GERTH and other Timor species are
en! irely devoid of external wall but thepresent specimens they partially dissap-

Explanation of Plate 8
Figs. la. b. Iranophy/lum /zmica/um !Go. n. sp.
a. Transverse section of the holotype: b. longitudinal section of the same specimen: x3.
Fig. 2. Lonsdaleias/raea ? sp.
Transverse section; x 5.
Fig. 3. Tf.'entzelella osobudaniensis IGo.
Transverse section of the holotype; x3.
Figs. 4a. h. Soclzllineophy/lum japonicum 1c:il, n. sp.
a. Transverse section in the mature stage of the holotype: X3: b. 1ransverse sectionin the immature stage of the same specimen; x2.5.
Figs. 5a. b, 6. Sochllineophyllum japonicum paucisePfafum Ic6, n. subsp.
5a. Transverse section in the mature stage of the holotype: 5b, longitudinal section of
the same specimen: x 1: 6, transverse section in the mature stage of paratype; x3.
Figs. 7a, b. /unandophyllum sp. indet.
Transverse section in the mature stage; x3.

!G6 : Permian Carats

AoKI and l e o Photo.

Plate 8

361.

Permian Corals from Hida Massif

pear. Such characters are recognizedsometimes in certain species of lVeutzelella, however, the columella is more
related to those of Lonsdaleiastraea.
Thus the present one has characters ofboth of these two genera and may be
an intermediate form. The present
species may he new to science but more
specimens are necessary before conclusive decision be given.
Occurrence and geological age:-Thesame as TVentzelella osobudaniensis leo.
Reg. no. 21014.
References
DoL'GLAS.]. A .. 1936. A Permo-Carboniferous
fauna from Southwest Persia (Iran): Pal.
Indica . .V. S .. Vol. 22. No. 6. pp. 1-59. pis.
1-5.
GERTH. II.. 1921. Die Anthozocn der Dyas vonTimor: Pat. t·on Timor, Lief. 9. ilbt. 16. pp.
65-147, pis. 145-150.
GRAB.\t:, A. W .. 1928. Paleozoic Corals ofChina: Pt. 1, Tetraseptata; Pal. Sinh·a, ser.
B, Vol. 2, fasc. 2. pp. 1-151. pis. 1-8.
IIERITSCH. F .. 19313. Korallen der Mo~kauer-,
Gshel-und Schwagerinen-Stufc der Karnischen Alpen: Palaeon/ogr., Bd. 83. Abt. A.
pp. 99·162. pi;;. 14-18.

85

HtLI.. D.. 1956, "Rugosa" in MooRE's Treatiseon I nvertehrate Paleontology. Pt. F; Geol.
Soc. America.
HtJAl'G. T. K .. 1932, Permian corals of South
China: Pal. Sinica. ser. B. Vol. 8, fasc. 2.
pp. 1-163, pis. 1-16.
Ico. H .. 1956a. 1\otes on the Osobudani conglomerate and some lower Permian fusulinids contained in its limestone Pebbles. Pt. 2; Sci. Rep .. Tokyo Unit·. Education,
Sec. C. Vol. 4. pp. 293-302. pis. 18-19.
- - , 195Gb. Ibid .. Pt. I : Proc. Trans., Pal. Soc.
japau. N. S .. No. 21. pp. 169-174. pl. 27.
- - . 1957. Fusulinids of Fukuji. SoutheasternPart of the llida Massif. Central Japan:
Sci. Rep., Tokyo Unit•. Education. Sec, C.
Vol. 5, No. 47. pp. 153-246, pis. 1-15.
IC\!\!EI, T., 1957, Two Permian corals from
the Mizuyagadani formation; four. Slziltshu Unit•., pp. 29-35. pis. 1-4.
LEED. II., 1956, Permian reef-building corals
from North Auckland Peninsula, New
Zealand; llu/1.. New Zealand Geo!. Surv.,
No. 25, pp. 15-24, pis. 1-6.
Mll'ATO, M., 1955, Japanese Carboniferous andPermian Corals ;Jour. Hokkaido Univ. hzst.
Geol. Min., No. 540, pp. 1-202. pis. 1-43.
WAAGEN, 'IV. and '0lE:"TZEL, ]., 1886, Salt
Range Fossils, Vol. 1, Productus-!imestone
fossils. 6, Coelenterata; Pal. Indica, ser.
13, pp. 835-924. pis. 97-116.

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 34, pp. 86-96, pl. 9, june 15, 1959

362.

ON THE MIOCENE PECTINIDAE FROJ\I THE ENVIRONS OFSENDAI: PART H. OK PECTEN SWIFT!! BERNARDI*
KOICHI.RO i\IASUDA
Department of Geology. Faculty of Education, Tohoku University{ilrEi~ftili:lfl~*fti!ff Pectinidae: .l(-0) 14. Pecten swijtii BER:'-iARDI /1:-'?t'"(: Pecten
swijtii BER:"\ARDI :;t~Vifif::0ml£f!llTJ~-':> iJ:, ff:;Ti c L-'L 1.;1; ~ 0./il!:19JO.'>i!1Hf1;1}olf!Wfill:HiJJ!1J~·
I?>~Gt.t'Lt'7.., *ftl!lt%fl(f!':J!,df~f4.>rf!i-Jr:M\TJ)~;I}:, tt*~"' Clzlamys cosrbensts(YoEOYO~L\). EJG:i -f O)!fl!f]JU: ~tl i? ft 9 b 0) c iJllll'lJ ~ :f1. '{"t 't:, *~·f;t, IUJi'1~f1j![JkCf b
ill!iJ· GO.'>{t'&fill&V'~t; B*J't:!il!. fll!:;t:. 'iilllitf~IJ• G0.m!f:EJ!0.&'i*yf{!:: '"'? '. 'L·!'fi!ilt L-. ffiJJilt
cltiJiSt~fj·. '· ~O:!il!'fi")t{l:J~~'£~%.;: L-t:,
J:fli EB :Jf. - fll~l'vlinami-Tsugaru-gun. Aomori Prefecture
in 1935 and from the Otsutsumi formation at Otsutsumi, Taiwa-machi, Kurokawa-gun. l\liyagi Prefecture in 1937.
However, it is considered that YoKOYA:-.rA's single right valve from Koshiba
is a synonym of Ch!amys cosibensis CY oKoYA~tA) which was described from thesame locality at an earlier elate, and thesingle right valve from Obashira probably represents a new subspecies of
ChlaiJiys cosibensis which will be described at another opportunity as Chlamys
cosibensis lianzazcae MAst:oA, n. subsp.,
and the single right valve reported from
6tsutsumi is Clllamys cosibensis lumzazcae,
though specimens referable to szt'iftii
have been collected from the same
locality by No:-.JuRA and l-L\TA 1. In thepresent article the reports with illustrations were reviewed but those \vith only
listed occurrences were rejected because
the original specimens could not be
studied.
Numerous .Recent and fossil specimens
were studied, and these included those
now preserved in the collections of the
Department of Geology, Faculty of Education, in the Institute of Geology andPaleontology, Faculty of Science, both

Introduction and Acknowledgements
Pecten su:iftii BER:'-i.\RDI (1858). a common Recent scallop in Northern Japan,
has been recorded from numerous localities of the Neogene and Pleistocene
formations of North Japan. Among theJapanese i\'iiocene Pect iniclae this species
is interesting because of its long geological range from the Early Miocene
and because of its confusing characters.
The fossil swiftii in Japan was firstdescribed from the .. Taga '' formation
at Hatsuzaki. Hitachi City, Ibaraki Prefecture by KocH!BE (1882). Subsequently
YoKOYA:\L\ described it from the Koshiba formation at Koshiba, Yokohama
City, Kanagawa Prefecture in 1920, fromthe'' Taga" formation at Tsurushihama,
Hitachi City in 1925. from Obashira.
Chichibu City, Saitama Prefecture in
1925 and from the Sawane formation at
Sawane, Sawada-machi. Sado-gun, 1\iigata Prefecture in 1926. No::-!l'RA and
IlATAI described it from the Daishaka
formation at Daishaka, Namioka-machi,* Received Oct. 14, 1958; read at the 7lst.
meeting of the Society at Kyoto. Sept. 27,
1958.
8G

362.

111iocene Pectinidae from the Envimns of Sendaiof the Tohoku l:niversity, and in the
Saito I-Io-on Kai l\luseum, all in Sendai
City. The results of examination on the
Recent and fossil su:ijtii and its geological significance are presented herein.
Acknowledgements arc due to Dr.
Kotora l-1.-HAI of the Department of
Geology, Faculty of Education, Tohoku
University, for kindly supervising thepresent work and also to l\'lr. Shin-ichi
HoN:-.IA of the Kanazawa High School atKanazawa. Sado Island, l\i igata Prefecture, for his assistance in collecting
specimens.
Description

Family Pectinidae
Subfamily Pectininae
Genus Ch!am_rs (BoLTEr-;) RooJr-;G, 1798
I

Subgenus Swiftopecten HERTLEIN. 1935
Clllamys iSu:i_ftopecten) swiftii(BERN\RD!),

1858

Plate 9. figures 1-1.

1867.

188:?.

1888.

1902.

1925.

1926.

l931.

Pecten stciftii BERl\ARD!. SCHRE"'CJ'.
Moll. 4mttrl. }·iordjap. Jleereas. p. 487.
pl. 21. ligs. 1-:.l.
Pecten striftii BERNARDI. KoCHIBE, Rika
Kai-s!ti. Tokyo Univ. Press. No. 4, p. i5.
pL 5. fig. :3.
Peden Slr~flii BERI"MWI. KOSTER und
KoBELT in l\1ARTI7'1 unci CHE~INITZ.
Syst. Conch. Cab .. Vol. 7. Pt. 2. !J. 1-!2.
pl. 40, fig. 3.
Pecten s~riftii BERN., YosiH\\'ARA. Zoot.
.llag. Tokyo, Vol. 14. No. 162, p. 1-U,
pl. 2. figs. 6a-b.
Pecten su·ijlii BERNARDI. YOKOYA\IA.
Jour. Coli. Sci .. Imp. Unit'. Tokyo, Vol.
-15. Art. :), p. 27. pl. 2, fig. 1.
Pectell S/VIjtii BERNARDI, Ym.;oy_~~IA,
Jour. Fac. Sci .. Imp. Univ. Tokyo, Vol.
1. Pt. 8, P- 303, pi. 37. figs. 5. 6.
Pecten (Pallium) su·iftii 13ER:'-IARDI.

87

GR:\"'T and GALE. Mem. San Diego Soc.
Nat. Hi st., Vol. 1. p. I il, pl. 10, figs.

la-b. 4a-b.
193-t. Chlamys swijtii (BER:'\ARDI), KINOSHITA and IsAHAYA. Rep. Fish. Sun; .. Hokkaido Fish. Exp. Sta .. No. 33. p. 14. pl.
10, fig. 7-L
1935. Pecten (Pallium) Slcijtii BERN.-\RDL~Ol\ll'RA and HAT.-\1, Saito flo-on Kai:l!us .. Res. Bull.. J\"o. 6, p. 98. p!. 9, fig.
8, pl. 10, figs. 3. 4. pl. 11. fig. 8, pL 13,
fig. :t1950. Clzlamys islandicus var. Sl!'iftii (BERN.-\RDI), Kl:BOTA, Sliinseidai-no-Kenkyu(Cenozoic Research). No. 6. p. 12. pl. 9.
figs. 66. 67
HJ5L Clz/amys swi[tii (BERNARDI). TAJ-:1 in
HrRASE. lltust. llandb. Shells Nat. Color,
Jaj>an. Adj. Ten·it., pl. 12. lig. 5.
1951. Ch/am_1•s Slcijtii (BER:-\ERDI), H.\BE,
GeneraJajxm. Shells. No. 1. p. 74. fig. 150.
1955. Chtamys su·ijtii (BER?\ARDI), HAHE,
Pub!. Akkeshi Mar. Bioi. Slat., 1\'o. 4, p.
6. pi 2, fig. 7.
1955. Ch!amys su.iftii (IkRN.\RDI). KIRA,
Color. lllust. Shells Japan, p. 99. pl. -19,
fig. 1-!.
1958. Clzlamys (Su·iflo}Jecten) su:ifli (BER7'ARDI). HABE. Pub!. Se/o :Uar. Bioi.
Lab .. Vol. 6, No. 3, p. 263. pl. 1:?, fig. 18.

Shell large and thick, much higher
than long, moderately inflated. inequilateral, posterior side longer than anterior, postero-dorsal side nearly straight
and antero-dorsal side gently curved,
ventral margin uneven corresponding toexternal sculpture; left valve somewhat
more convex than right; both valvesradiately ribbed and forming a!1 angleof about 70° at apex .
Right valve with four, rather prominent. round-topped radial ribs, two subordinate radial ribs near submargins,intercalary threads andconcentric
growth lines. and ornamented by rather
distinct fine network; radial ribs broader
than their interspaces. gently bend anteriorly towards ventral margin, sculp-

88Koichiro MASUDA

tured with several, nearly equal, fineradial threads \vhich are separated byshallow and narrow longitudinal furrows
and usually bifurcate towards ventral
margin. but sometimes backs of radialribs rather smooth; two subordinate
radial ribs near submargins separated
from main radial ribs by shallow andnarrow interspaces, usually slender andobsolete, and sculptured with a few.
faint, fine radial threads; four to six
intercalary threads between radial ribs
sometimes bifurcate near ventral margin.
and nearly equal to radial threads ofbacks of radial ribs in strength atventral margin; primary intercalarythreads two or three near beak. increase
their number towards ventral margin;submargins sculptured with numerous.
faint. fine unequal radial threads which
are fainter and finer than those of central part of disc: concentric constrictions rather distinct: sculpture of backsof radial ribs usually more distinct at
ventral margin and concentric plait thanthose of other places: anterior auricle
very large. nearly triangular in shape.
much larger and longer than posterior
one. furnished with rather deep andwide byssal notch, rather narrow byssal
area, and sculptured with several. moreor less elevated. distinct radial threads.
somewhat Jess distinct
intercalarythreads and concentric lines; posteriorauricle similar to anterior in sculpture.
though radial threads less distinct thanthose of anterior; hinge with rather
simple cardinal crura. rather distinct
ctenolium. and deep and wide resilial
pit provided with elevated. distinct
lateral ridges; hinge plate rather fiat
and wide. and sculptured with fine. faintstriae parallel to hinge line in adultspecimen. Left valve with five, prominent. round-topped. rather smooth radialribs, fine intercalary threads and con-centric growth lines. and ornamented
by rather distinct fine network; radialribs narrower than their interspaces,and sculptured with several. rather
faint, fine radial threads which are nearly equal to their interspaces and rarely divided into two parts by a shallow
longitudinal furrow near ventral margin:
intercalary threads seven to ten, narro·wer than their interspaces on upper
half of disc but nearly equal at ventral
margin. and rarely divided into twoparts by a shallow longitudinal furrownear ventral margin; primary intercalarythreads three to four near beak and increase their number towards ventral
margin; concentric constrictions usuallyconspicuous, by which radial ribs appear
nodose; anterior auricle triangular inshape. and sculptured with several. distinct. elevated radial threads. somewhat
Jess distinct intercalary threads andrather distinct concentric lines, by whichradial threads appear somewhat nodose;
posterior auricle similar to anterior in
sculpture. though radial threads muchless distinct than those of anterior.
Interior surface of both valves distinctly
or gently folded corresponding to external sculpture and with fine serration at
ventral margin.
Dimensions :-Shown in Table 1.
Comparison and Affinity :-Chlamys(Swijtopecten) parme/eei reported by D.uL
(1898) from the Pliocene of Caliiornia
and Chlamys (Szcijtopecten) l?indlei described by DALL (1920) from the Plioceneof Alaska are closely related to thepresent species, but as pointed out by
D.\LL (1920). the former differs fromthe present one in having a smaller
shell and peculiar microscopic squamation, and the latter by the lacking ofconcentric waves due to the restingstages. The present species also rescmbles Cltlamys wattsi and C/ilamys rcattsi

362.

MioclJne Pectinidae j1·om the Environs of Sendai

8f)

Table L Measurements on the seh:cted specimens of sw~ftii (in mm.)
'-'

..::!

be

i::IJ
t:

t:

ro
w
0

....

..::::

0(,

;:j)

~

B

,.

c

II
II

131
110
115
97
111.5 98
100. 5 87.5
79
68
39
29.5
35
29.5
35
28
68.5 53. 5
57. 5
47.8
57
43
5:'!.5 44
26.6
21.4
99
81
96.8 8150
40
91.5 80.5
91
76
81
65
76
70.5
76
63
30
24
17.5 14. 7
63 I 52
40
33
36
29.5
I
I

II

'0."

.::-!

"'

>

-;;:;

'"ro

It'

>

20.5 75'2470'·19. 5 ' 20. 5 70"
21. s 70'
34
14
70'
17
6.8
70"
16
65
70'
7
70'
11.2 70'2511
70'26.5 10.7
70'
28
10. 5 70"
4. 2 70'
23. 5 I 70'
70"
39 ' 23
8. 5
70'
70'
42
18
41
I 22 I 70'
70'
33. 5 1534 , 15.5 70'
34 , 15.5 I
16 : 670'
I 2. 8 I 70'
17 ' 70'
18 1 7. 5 : 70'
: 6
75'

R

]1_1_

R

I

55

,

1

1

1

I

I ..J

R
R
R
R
L
R
R
R
R
R

R
R
R
R
R
L
L
L

II

I

-

92
96
103
103
89
75
89
75
88
76
88
76
75. 5 63
88. 5 69
101
88
101
88
89
75
89
75
111
94.5
105
91.7
103
93
103
93
102
88
120
101
119
100.5
100
88

N

H
I•
II

I
I

"

!

II

I
!

"

I

II

I I

I

J
II

K
I
/1

"
I

<

E
F
G

II
/1

L
II
II

I
I
I

:J

i

>
d

>

-----

27. 5
30
29
845
79
86
86

D

I

~

L
L
L
R
R

36
35
34

II

R

0.

I

c

!

u

B
0

<

J

..J

A

'"

17

4. 8
6. 7
7
15
29
18.5
21.5
25.5
14.3
19
14
17
10.9
18. 2
21

70' L
70' L
18.5
70' II L-70' R45
70' I L43.5 I
70' I R50
70' R+
50
70' L+'12. 570' R+
42.5
70' L+
41. 5
70' R+
4J. 5 I
70' L+
34
70' R
43
70" L
58
70' R+
58
70' L+
25.5
46
14.7 I 70' R+
46
I 20. 5 ' 70' L+
48 i 25
70' R
48 I 24 I 70' R
52.5 I 23 I 70' R+
52.5
28 I 70' L+
21. s II 70' L
50
20
70' R
'
59.5
28.5 ' 70" ' L
52
70' L
26
I

I

----

+: Intact valves. A: Daishaka, Namioka-machi, Minami·Tsugaru·gun, Aomori Pref. (Pliocene). B: Sawane, Sado Island, Niigata Pref. (Pliocene). C: Tayazawa, Wakimoto. Oga
City. Akita Pref. (Pliocene). D: Chikagawa. Tanabu-machi, Shimokita-gun, Aomori Pref.
(Pliocene). E: Pirika, Imagane-machi. Setana-gun, Hokkaido (Pliocene). F: l\Iadate. Todamura. Ichihara-gun, Chiba Prcf. (Pleistocene). G: ?v1anui, cast coast of Southern Sagha·
lien (Recent). H: Dui-March, Northern Saghalien (l{eccnt). I: Shizugawa. Motoyoshigun, Miyagi Pre f. (Recent). J : Kescn-nurna. Miyagi Pref. (Recent). K: Mutsu Bay. Aomori Pref. (Recent). L: Shimpo, Kankyo-Nando. Korea (Recent).

!10

Koichiro M11SUDA

var. monmi which were described fromthe Pliocene of California by ARNOLD(1906). but it can be distinguished fromthe former by its posteriorly contorted
shell. smaller number of intercalarythreads, shape of auricle and rather
large posterior auricle. and from thelatter by the above mentioned characters and rather less distinct radial
threads on the backs of radial ribs andin their interspaces than those of thepresent one. From Chlamys etche~;oini
which was described by AKDERSOK (1905)
from the Pliocene of California, it isdistinguishable by its smaller shell andthe characters of the radial ribs. This
speciesmuchresembles
Chlamyscosibensis which was described by YoIWY,\~IA (1911) from the Pliocene Koshiha format ion, but it can be distinguishedfrom cosilie1z.~is by its large. posteriorly
contorted shell which is much higher
than long, smaller apical angle. trianguJar anterior auricle. hinge with rather
simple cardin::~! crura and nearly flat
left valve in the young shell. Chlam.rs
l?ilamurai which was described by KoTAKA ll9:'ifi) from the Oligocene Isomatsu
formation. Aomori Prefecture. is distinguishable from the present one in thegreater number of and the differentmode of bifurcation of the radial ribs
and intercalary threads.
Remarks :--This species is characterized by its large and thick. posteriorly
contorted shell which forms an angle ofabout 70° at apex and is much higher
than long, four. rather prominent roundtopped radial ribs which are sculptured
with several. fine radial threads, t \\'O
subordinate radial ribs near submargins.
fine intercalary threads. rather conspicuous concentric constrictions, Yery large
triangular anterior auricle, and flat
hinge plate which is sculptured with
faint. !inc striae parallel to the hingeline in the right valve. The left valve
is characterized hy its five (rarely fouror six) conspicuously prominent, roundtopped radial ribs which are usually
nodose and by its young shell which isnearly fiat or rarely a little concave
upwards. As pointed by YoKOYA~t.\(1926) and ~OMURA and lhn1 (1935), theradial ribs sometimes become strong
and elevated but may be low and flattened. Sometimes the sculptures ofradial ribs are obscure. especially in thecase of the conspicuously nodosed radialribs of the left Yah-e.
Some differences between the fossil
and Recent specimens arc observed. In
the Miocene specimens the radial threads
on the backs of radial ribs and in theirinterspaces of both valves are usuallymore numerous and more close-set thanthose from the Pliocene. Pleistocene andRecent, and the fossil left valve isusually nearly flat or rarely more orless concaved upwards in the young
stage. while the Recent shells are gently inflated and tend to gradually increase
their convexity towards the ventral
margin. and moreover. the concentric
constrictions are rather less conspicuousthan those of the fossil shells. but thecharacteristics except for the above
mentioned are quite similar to eachother. In other words. the variabilityof the left valve is more progressionalor responds more to the environmental
conditions than the right valve (~-IAst:­DA, 1957).
Described specimens :-l{ight stream
cliff. northwest of Daishaka. Namiokamachi. \'iinami-Tsugaru-~un. Aomori
Prefecture. Conglomeratic. calcareouscoarse-grained sandstone of the Daishaka
formation (Pliocene). DGS, Reg. No. 3684.
Occurrence ;-Otsutsumi formation in
Miyagi Prefecture and Ginzan formationin Yamagata Prefecture: Late Early362. Miocene Pectinidae from the Environs of Sendai
l\liocenc.
" Taga" formation in lbaraki Prefecture and Suenomatsuyama formation in
I watc Prefecture : Late l'vl iocene.
Sawane and Shiraiwa formations in
Niigata Prefecture. Sasaoka and Shibikawa formations in Akita Prefecture,
Daishaka and IJamada formations in
Aomori Prefecture. and Kami-iso andSetana formations in Hokkaido: Pliocene.
Narita formation in Chilm Prefecture,and Shishinai and Kushiro formationsin Hokkaido: Pleistocene (text-fig. 1).
Geo;.,traplzical

Distribution :-~orthern

Honshli. Hokkaido. Kurile Islands. Saghalien, West Coast of Amurland. Tartary
Strait. ~ortheastcrn horea, Korea Strait
and off Alaska.
Geological ra-1/J.[e :-Late Early Miocene
to Recent.
Hemarks on the Recent swiftii

The Recent smftii has a wide geographical distribution extending Northern
Honshil to as far south as Fukushima
Prefecture along the Pacific and to as
far south as Fukui Prefecture along theJapan Sea. north"·ards to 1-Iokkaido.
Kuri lc Islands, Saghalien. west wards tothe Korea Strait. northeastern coast of
Korea and the west coast of Amurland(text-fig. 1\ and it is also stated to beliving off Alaska. The area of distribution in the Pacific is influenced by the
Oyashio Cold Current. in the Japan Sea
by the Liman Stream (~orthern Korea
Cold Current) and in the Okhotsk Sea
by the Eastern Saghalicn Cold Current(text-fig. 1). However. sometimes thisspecies lives in areas influenced by thewarm current as l\'Iutsu Ray, Tsugaru
Strait. Wakasa Bay and the Korea Strait.
These areas arc influenced annually orseasonally by the cold current. Therefore, it is evident that szci[tii is a cold

91

water inhabitant, though it is more orless eurythermal. and stci[tii seems toprefer a rather shallow clean sea bottomof rock or gravels.
Some morphological differences areobserved bet ween the specimens from
Saghalien and those from Northern Honshfi. The concentric constrictions of theleft valve from Saghalien arc somewhat
less developed than those from Northern
Honshfi. so that. the radial ribs of theformer are usually rat her low and flattened and the com·exity of the former
is somewhat less than that of the latter.
but the variability of the right valve
is rather less than that of the left valve.
Although the number of examined specimens are not abundant, the mentioned
facts suggest that the specimens living
in northern regions are somewhat lessinfluenced by the variation in the Z:-1nual water temperature than those liYing in more southern areas. owing to
the smaller thermal range of the annual
water temperature compared with thatof the southern area. For instance, according to E~;\r\" (19:)3) the water on
the continental part of the Japan Sea.
in the southern part of the Okhotsk Sea
and the nort hem islands of the Kuri legroup, is characterized by an arctic temperature during the whole year at thedepth below 35 to 30m. And the surface water temperature in the Northern
Kurile Islands is I'C in August and-1 T in February. while that of thesouthwest coast of Hokkaido is 15°C to
18oC in August and less than OOC in
February. Concerning such case Nol'.lliRA and HATM (19::16) have discussed on
the living Neptunea arlltritica BEI~NARDJ.
The above mentioned data may aid toanalyse the environmental conditions of
the fossil stt'iftii, but further data arenecessary to settle this problem.

Ko:chiro MASUDr1

92
Geological SignificanceAs known at present, the oldest occurrence of stciflii is from the Otsutsumi
and Ginzan formations in Northeastern
Honshu, japan, where it is rather rare.
The next occurrence of swiftii is the Late

Miocene Suenomatsuyama and "Taga"
formations, where it is associated withseveral rather cold water species. Abundant specimens of swi[tii occur from the
Pliocene Sawane, Shiraiwa. Sasaoka,
Hamada, Daishaka, Kami-iso and Setana
formations in association with many

148

152

,
46
Current -Sy a tem
42

38

38

34

30

30

.• p

of
Recent and Fossil Chla~ys sw1ft11
124

1?8

132

136

140

Text·figurc l.

144

148

362.

Miocene Pectinidae from the Environs of Sendai

boreal molluscan shells as Patinopecten
yessoensis (J .'\ Y ). Pododesmus macroschisrna(D~-:snAYEs), Astarte a!askensis DALL, Con·c/wcele disjzmcta GAnn. Clinocardium ciliatum (FAnRtctcs). Neptzmea lira/a (G:-.tELtl'),
etc .. boreal forms of Bryozoa (KATAOK.\,
1957) and foraminifers. Swijtii is also
known from the Pleistocene Narita formation in Chiba Prefecture and from
Shishinai and Kushiro formations in
Hokkaido.
From the morphological difference
between the Recent and fossil specimens
which is but little. it is inferred thatthe present species acquired its stasigenesis during the late Early :Vliocene,and survived to the present with little
morphological variation. This view isupheld from the gradual increase in the
incli vidual number of swijtii in good
agreement with the increase of the associated boreal fauna such as molluscs,
bryozoans and foraminifers from thelate Early l\Iiocene through the Pliocene
to the Recent.
Chlamys nutteri (AR:-.iOt.n) and Ch!amys(Swiftopecten) kindlei (DAt.L) were regarded
as the varieties of swijtii by GRA"'T and
GAr.r: (1931) and C!z/amys zcattsi (ARKOLD),

C/zlamys wattsi var. morcmi (ARxot.n),Clz/amys cosibensis (YoKoYA~1A) and "Pecten tiggerinus" YoKov A:O.tA (not of :VTL't.LER) also included into C/zlamys swiftii
var. etclzegoini (A:-mERso:--~) by the sameauthors. Moreover, they considered that
Clzlamys lzeteroglypta (YoKOYA~tA) which
was described from the Pliocene Smvane
formation is a synonym of Clz!amys swijtii
var. nut!eri (AR:--~OLD), and that C!zlamys(Szcijtopecten) parmeleei (DAt.t.) is one of
into swijtii. Subsequently. No11n.:R,\ and
HATAI (1935) considered that YoKOYA~·tA's
species and Clzlamys nutteri should beheld as distinct species. The writeragrees with GRA:o-;T and GALE in regarding kindlei as a subspecies of swijtii andwith NoMURA and H,\TAt in holding theJapanese species and C!z!amys nutteri as
distinct from one another. but the writeris inclined to consider parmeleei as asubspecies of swijtii. It is inferred that
Chlamys (Szcijtopecten) swiflii kindlei and
Clzlamys (Stciftopecten) swiftii pamzeleei
are descended from stcijtii (s. s.) as aresult of its eastward migration fromJapan to the western coast of America
followed by localization and adaptation.
and that both subspecies became extinct

Explanation of Text-figure 1.
Current·System:
a: Kuroshio Warm Current. b: Tsushima ·warm Current. c: Oyashio Cold
Current. d: Liman Stream (North Korean Cold Current). e: Eastern Saghalien
Cold Current.
Distribution Map:.. . . . .... Fossil locality:
1: Kushiro (Pleistocene). 2: Shishinai (Pleistocene). 3: Setana (Pliocene).
4: Kami·iso (Pliocene). 5: Hamada (Pliocene). 6: Daishaka (Pliocene). 7:
Suenomatsuyama (Miocene). 8: Sasaoka and Shibikawa (Pliocene). 9: Ginzan (Miocene). 10: Otsutsumi (1\Iiocene). 11: Sa wane (Pliocene). 12: Taga
(Miocene). 13: Madachi (Pleistocene). 14: Shiraiwa (Pliocene).
x ........ Recent locality:
1: 'Vakasa Bay. 2: Onahama. 3: Kesen-numa and Shizugawa. 4: Korea Strait.
5: Shimpo. 6: Tsugaru Strait. 7: :tv!utsu Bay. 8: Hakodate. 9: Okujiri andKumaishi. 10: Otaru Bay. 11: Teshio. 12: Rishiri. 13: Kitami. U: Kushiro
and Akkeshi. 15: Nemuro and Hanasaki. 16: Shakotan. 17: Kunashiri. 18:
Yetorup. 19: Paramushir. 20: Manui. 21: Tartary Strait. 22: Esutoru. 23:
Honto.

Koiclziro 11-fAsuDA

94

before the end of the Pliocene. How·
ever. to settle this problem the fossil
specimens of swiftii and its related forms
from California and Alaska should bestudied comparatively and more Recent
specimens from the northern Pacificmust be examined.
References
AR:-<OLD. R. (1906). The Tertiary and Quater·nary Pectens of California. Prof Paper.
U.S. Geol. Sur!' .. 1\'o. 17. pp. 7-146, 53 pis.
DAJ.L, W. H. (1898). Contributions to the
Tertiary Fauna of Florida. with especial
Reference to the Miocene Silex Beds of
Tampa and the Pliocene Beds of C:~loo·sahatchie River.
Trans. Wagner Free
!nsf. Sci .. Vol. 3, Pt ..J. pp. 571-9H. 12 pis.
- - (1920). Pliocene and Pleistocene Fossils
from the Arctic Coast of Alaska and the
Auriferous Beaches of Nome. Norton
Sound, Alaska. Prof. l'ajJer. U.S. Geol.
Sun· .. lVo. 125-C, pp. 23-34. 2 pis.
Dt::\KER, ·w. (1882). Index Molluscorum
Maris Japonici. pp. 1-301. 16 pis.
EK:-.rAx, S. (1953). Zoogeography of the Sea.
pp. 1-.to.t Sidgwick and Jackson, Ltd..
London.
GRA"T. U.S. and H. R. GALE (1931). Catalo·
gue of the Marine Pliocene and Pleisto·
cene 1\lollusca of California and AdjacentRegion,.. Jlfem. San Diego Soc. Nat. Hist ..
Vol. 1. pp. 7-1036. 32 pis.
HAnE, T. (1951). Genera of Japanese Shells.
Pelecypoda No. I. pp. 7-96. figs. 1-192.
- - (1955), Fauna of Akkeshi Bay. 21.
Pelccypoda and Scaphopoda. Pub!. :lll·keshi Afar. Bioi. Stat., No. 4. pp. 1-31. 7
pis.
(1958). Report on the Mollusca chielly
collected by the S. S. Soyo-maru of theImperial Fisheries Experimental Stationon the Continental Shelf bordering Japan
during the Years 1922-1930. Part 3.
Larnellibranchia (I). Pub!. Seto. Mar.
Bioi. Lab., Vol. 6. No. 3. pp. 2.U-279, 3pis.
HA:--1ZA \\'A, S. (1950), Tertiary Paleogeographyof North Japan. Short Papers. Ins!. Geol.
Paleont. To!zolm Unit•., No. 2. pp. 74-98.
liATAI. K. (1936), A Note on the Distribu·
tion of Certain Species of Marine lnYCI'·
tebrates. Bull. Biogeogr. Soc. ]apa11, Vol.
6, No. 12. pp. 123-141.
- - and S. Nrsl\·,\:-.L'\ (1939). Palaeontologi·<.:al Notes on Certain Japanese Scallops.
four. Ceo!. Soc. Japan. Yo!. 46, No. 544,
pp. 37-46. 3 text-figs.
- - (1939). Migration of Marine Fauna in
the North Pacific Area during the Youn·
ger Cenozoic Era.
Proc. Sixth PacificSci. Congr .. pp. 479-482.
- - (1950), Cenozoic Mollusca from Aomori
Prefecture, Japan. four. Conch., Vol. 90,
pp. 128-1:~6.
l-IERTLEIK, L. G. (1935). The Templeton Cro·ker Expedition of the California Academyof Sciences, 1932. Proc. Calif A.cad. Sci ..
Ser. 4. Vol. 21. No. 25. pp. 301-32·1. 2 pis.
- - (1936). Three New Sections and Retifi·
cations of Some Specific Xames in the
Pectinidac. Nautilus, Vol. 40. Nos. 1-2.
pp. 1-8.
KAl\EHARA, K. (19,12), Fossil Mollusca from
Tayazawa. \Vakimoto·mura. Katanisi Oil
Field. Jour. Ceo/. Soc . .fapan, Vol. -19. !Vo.
581. pp. 130-133. 1 pl.
KATAOKA. J, (1957), Bryozoa from the Dai·shaka Formation (Pliocene). Minami·
Tsugaru-gun, Aomori Prefecture. Trans.
Proc. Palaeont. Soc. Japan, N. S., No. 28,
pp. 143-153. l pl.
KJxosr!IT.·\. T. and T. lsAHAYA (1934). Cata·
Iogue of l\·Iarinc l\ilollusca from I-Iokkaido.

Rep. Fish. Sum. Elokkaido Fich. ExjJ. Stat.,.\'o. 33. pp. 1-19. 15 pis.
KocHIBE, T. (1882), J6hoku Chishitsu Hen(Geology of Northern Hita<.:hi).
Rika
1\ai·shi. Tokyo Unil•. press. No. 4. pp. l153, 9 pis.
KoTAK.\. T. (1955). Molluscan Fauna fromthe Oligocene Tsomatsu Formation, Ao·mori Prefecture, Northeast Japan. Saito
Ho·on Kai Mus.. Res. Bull., No. 24. pp.
23-30. l pl.
KunoTA, K. (1950). Explanation of Cenozoic
Fossils from Northern Japan, 9, Fossil
Pectinidae from the Setana Series. Shin·

362.

Miocene Pectinidae from the Environs of Sendai

seidai-no·KI'IIIiyu (Cenozoic Research). No.
6, pp. 12-18. 2 pis.
KuRODA. T. (192~1-1935), An Illustrated Cata·
Iogue of japanese Shells. Parts. 1-16.
J'emts, Vols. 1-5, Append. pp. 1-154.
- - and K. KoBA (1933). l\lolluscan Faunaof the Northern Kurile Islands. Bull.
Biogeogr. Soc. Japan, Vol. 4. No. 2, pp.
151-170. 1 pl.
KesTER. H. C. und W. KonEL T in MARTI?'!
und Cllnt:-.:ITZ (1888). Die GattungenSpondy/us und Pecten. Syst. Conch. Cab.,
Vol. 7. Pt. 2. pp. 1-296. 72 pis.
MAst·oA. K. (1%1). A Note on Miyagipec/en
ma/sumoriensis 1\IASllDA. Saito llo-011 Kai•l!us., Res. Bull., No. 26. pp. 31-39, 1 pl.
Nnl'o, H. (193·1), On the Soundings from the
Bottom of the Western Part of the Tsu ·garu Strait. four. Geol. Soc. Japan. Vol.
41, No. 49:>, pp. 713-726.
- - (1949), On the Bottom Deposits on the
Banks at Mouth of \Vakasa Bay and on
the Adjacent Continental Shelf. Japan.
four. Geol. G!'ogr., J'o!. 2 7, Nos. 1-·1. pp.
193-225. 2 r>ls.
Nol\!LA:"O, .f. 0. (1917). The Etchegoin Pliocene of l\•liddle California. Univ. Cal~(.
Pub/. (;col .. 1/o/. 10. pp. 191-2-10. 7 pis.
::\OJ\.!l'l~''· S. and N. IIATAF: (1928), Outlinesof the Distribution of Sonic Recent l\•lol·
lusca on the Coast of Korea. four. Nat.
His!. Chosen, No. fi, pp. 1-9.
- - and II. Tst·:-.:orM (1933). Recent l\Iollusca
from Onahama Bay, 1-lukushima Prefecture. Saito llo-on Kai JHus .. 1Votes. Vol. 3,
pp. 1-19.
--and K. IL\T,\1 (1935). Pliocene ~lollusca
from the Daishaka Shell Beds in theVicinity of Daisyaka. Aomori-ken. Xorth·east Honsyu. Japan. Saito Ho-on Kai
Mus., Res. Bull.. 1Vo 6, pp. 83-137, 5 pis.
--and - - (1936), A Note Concerning Dataon the Bathymetric Range of Certain
Marine Animals and Remarks on the
Geology of the Neogene Formation in
Northeast llonsyu, Japan and their Depth
of Sedimentation as indicated by the Fossil Fauna. Ibid., No. 10. pp. 231-33·1.
- - and - - (1937), A List of the Miocene
Mollusca and Brachiopoda Collected fromthe Region lying North of the Nanakita
Ri,·er. in the Vicinity of Sendai. Rikuzen
Province. japan. Ibid .. 1\To. 13, pp. 121145, 5 pis.
- - and - - (1937). On the Variation of
Neptunea arthritica BER:":M~DI. from the~orthcrn and Central
llonsy(t, Japan.
Ibid., lv'o. 13, pp. 1-5, 2 pis.
- - and - - (1938). On Some Fossils from
Akita Prefecture. Northeast Honsyu,
japan. Japan. four. Geo/. Ceogr., Vol. 16.
Nos. 1-2. pp. 39-6·1. 5 text·figs.
Or:--;o~IIKADO, T. (1937). l\lolluscan Fossils
from the Pleistocene Deposit of Sisinai
in Tobetu-mura. Isikari-gun, llokkaido .
four. Ceo!. Soc. Japan. T"ol ..J.J, No. 520.
pp. 65-70.
OY.\:0.1:\, K (1951). On Mollusca dn~dged fromoff Kumaisi with Notes on Hise and Fallof Ocean-current. ,lJisc. Ref'· Rl's. lust.
Nat. Re.~ .. Nos. 19-20. pp. 137--141.
- - (1952). Palaeontological studies on Pectens. Tbid .. No. 25. pp. 24-30.
SAsA. Y. (1939), On the Kusiro Series. thelowet· Pleistocene Deposils in Eastern
1-Iokkaido. japan. ]ub. Pu/JI. Comm. I'ro.f.
H. Yabe's 60th llirthday, Vol. 1, pp. 5G9-587.
ScHRE!'\CK. L. (1867). Molluskt-n des AmurLandes und des Nonljapanischen l\'lccres.
Reisen und Forsclmng :1mur/ande in dem
1854-1856. Vol. 2. Pt. 3, pp. 259-976, 17
pis.
SttGAI. K .. II. MATSU, s. SATO, Y. 1\tT:\KA\\'A,l\I. SASAKI. M. MrYASIIITA and II. !\.\\\':\·em (1957). Explanatory Text of the joban
Coal Field. Geologica! i\laps of the Coal
Fields of japan. I. Ceo/. Sun•. fa/XJ11, pp.
1-H3, 58 text-figs .. 3 maps.
YoKOYA~IA, M. (1920). Fossils from the Miura Peninsula and its Immediate ~orth.
four. Col!. Sci .. Imp. Unh•. Tokyo, Vol. 39,
Art. 6. pp. 1-193, 20 pis.
- - (1925). Molluscan Remains from theUppermost Part of the Jo-ban Coal Field.
Ibid .. Vol. 45. Art. :., pp. 1-3·1. I) I>ls.
- - (1926). Fossil Shells from Sado. Ibid.,
Vol. 1. Pt. 8. pp. 249-312. G pis.
YosHtWARA, S. (1902), Japanese Shells (Lamellibranchs). Zoo!. Mag. Toltyo, Vol. 1-1,
l'lo. 168. pp. 141-145. 5 pis.

96

Koichiro MASUDA

Explanation of Plate 9
Chlamys (Swiftopecten) swijtii (BER~c\RDI)
Fig. 1. Left valve, x 1. SM. Reg. No. 4527. Loc. Otsutsumi, Taiwa-machi, Kurokawa-gun, 1\Jiyagi
Prefecture. Otsutsumi formation.
Figs. 2, 3. Left valve, X 1. Sl\t Reg. No. 16827. Loc. Tominaga, Wakimoto-machi, Oga City,
Akita Prefecture. Shibikawa formation.
Figs. 4, 5. Right valve. xl. SM. Reg. No. 21266. Loc. Tayazawa, Wakimoto·machi, Oga City,
Akita Prefecture. Sh!bikawa formation.
Figs. 6a-b. a, Right valve, X2/3. b, Hinge area of Fig. 6a, xl. DGS, Reg. ~o. 3684. Loc.
Right stream cliff, northwest of Daishaka, Namioka-machi, Minami-Tsugaru-gun. Aomori
Prefecture. Daishaka formation.
Fig. 7. Left valve, xca. 1. DGS, Reg. No. 3699. Loc. Kaidate·no-sawa, Sawada-machi. Sado-gun,
Niigata Prefecture. Sawane formation.

M ASUDA :Miocene Pectinidae

MAsuoA photo.

Plate 9Trans. Proc. Palaeont. Soc. Japan. N. S .. No. 34. pp. 97-104, june 15. 1959

86:3.

TRIGONIOIDES AND ITS CLASSIFICATION(Studies on the Molluscan Fauna of the Cretaceous
Inkstone Series.

Part 2)*YOSHIHJSA OTA
Fukuoka Liberal Arts College

I Introduction
T1·igonioides KoBA Y .\Sill and St:zc~<: 1(1936) is an important genus in the nonmarine Cretaceous fauna of Eastern Asia.
They expressed an interesting opinion
that its peculiarities are due to adaptation of trigoniid to a new non-marine
environment "·hich \vas produced bv the
Sakawa orogeny. Subsequently it. wasdiscovered from various districts on thecontinental side of Eastern Asia. Especially important is MATSl'MOTo's discovery of shallow sublittoral marine beds
from the upper Gosyonoura group in\Vhich Trigonioides bearing brackish or
fresh water sediment is intercalated.
Now seven species are known of thegenus. Previously its classification wasmade chiefly by its outline and ornament
but a careful comparison among num·erous specimens has shown that variation in outline and ornaments is fairlv
wide even among the shells from on~
locality. Seven species including one
new subspecies are here recognized by a
new standpoint and their phylogenetic
relationship is discussed.
The writer expresses his sincere thanks* ReceiYctl July 28. 1958: read Feb. H.
1959, at Hiroshima University.

to Prof. T. KoB.:\YASHI of the Universitv
of Tokyo for kind guidance and reading
manuscript. to Prof. T. !\1ATSl'~IOTO of
the Kyusyu UniYersity and Dr. K. Su:eKI of the Research Institute for Natural
Resources for encouragement.

JI

Historical review

1. Ko£3,\Y.-\SIIl and SLzn.:1 (1936) erected the genus in describing T. kodairaifrom the Lower Cretaceous Naktong
series ISuimondo beds) of S. Korea andWakino series (Rikimaru beds) of N.
Kyusyu, Japan. From the hinge nature
it was referred to the Trigoniidae. Its
principal speciality in surface marking
was considered to depend on the changeof the habitat from marine to fresh
water.
2. HoFFET (1937) described four new
species of Trigonioides (kobayashi. laotiae.
trigouus and diversicostatus) from theSenonian of Laos and arrived at the conciusion that Trigonioides is a trigonoid
shell distinguishable from Trigonia in
hinge teeth and surface ornament.
3. MATsnioTo (1938) described T.
kobayashii from the upper Gosyonouragroup and pointed out the difference
between Trigonioides and Trigonia besidethe diagnostic shell features.

Yoslzihisa OTA

98

4. Kou.-\YASIII and St:zl:KI (1940) pro·
posed a new name T. matsumotoi for
2\L-\Tst::-.loTo's species because it is preoccupied by HoFFET·s. SnwKI (1940)
instituted a new genus. Hoffetrigol!ia
and placed HDFFn's four species in it.
ln addition, T. kodairai paucisu/catus was
described by SL'ZL'"' from t llc lower
Siragi series.
5. KonAYASIII and SntTI (l\J4l) described T. kodairai from the Lower Cretaceous Talatzu series.
6. SuzuK 1 (19,13) restudied the Naktong fauna with his new collections.
The detailed features of the pscuclocardinal teeth of Trigonioides were unknownat that time, but T. kadairai from theupper Naktong shows the hinge featureclearly. He said that its hinge features are identical with those of T.
kodairai paucisulwtus from the Siragi
series and agree with the essential features with those of T. matsumoloi. andits ornament is intermediate between
the typical form and paucisu/catu.~.
7. L. R. Cox (1955) identified an internal mould from the lower \Vakino subgroup with T. kodairai. Because its
hinge structure and characteristic ornaments are so common in the typicalunion ids. i. c. Castalia and Ni/Jftononaia,
he withdrew new family, Trigonioididae
which he had proposed in 1952.
8. KonAYASHI (1956) redescribed thedentition of Trif,fonioides and clarified its
distinction from that of the unionid.
Thus the Trigonioididae were revived
as a solid family. However. lle opined
HoffelriKollia to be a synonym of Trigouiaides.
III On the classifkationof Trigonioides

Trigmzioides has been classified as follows :1) Subtrapezoidal in outline, and sculp-

ture found all over the surface ....
.......................... T. lwdairai2) Rounded in outline, and sculpture
remaining only in umbonal and posterior parts .. T. kodairai paucisulcatus
3) Rounded in outline, and similar toT. lwdairai sculpture .. T. ma/sumotoi
4) Trigonal but more rounded than T.
lwdaimi. and similar to T. lwdairai
sculpture ................ T. /aotiae
5) Trigonal and inequilateral. ........ .
. . . . . . . . . . . . . . . . . . . . . . . . T. kobayashi6) Trigonal and equilateral .. T. trigon us7) Elliptical and sculpture different
from the precedings in a few diagonal plications in front of umbonal
angulation ........ T. dit•ersicostatus
In this classification, the outline andsculpture are seriously taken for the
specific distinction. If one examines
many specimens from a horizon, however, wide variation can be seen in outline and even in ornamcntion. Therefore, the above classification can notalways be applicable to Triwmioides.
A) Shell-outline
a. It has been said that matsumotoi
is distinct from kodaimi in the morerounded outline. But it was found that

0_

(Qmm

00
Oo

Text-figure 1. Variation of shell-outlines
of T. matsumotoi, showing subelliptical,
subtrigunal and intergradational forms.

363.

Trigonioides and its classification

several elongated specimens of the former species can not be distinguishedfrom lwdairai in outline.
b. The outline of matsumotoi fromthe same horizon is fairly variable asshown in Text-fig. 1. Their outlines arelinked from subtrigonal to subellipticalby intermediate forms.
c. The writer has examined only a
few Laos specimens. HoFFET·s report
does not give the frequency of occurrence. Text-fig. ~ was prepared from99

his Plates I. ll and III to show variationsin shell-outline. As shown in 3a and 3bof laotiae. they agree with lzodaimi insubelliptical outline. Kobayashi (2) also
agrees ·with the holotype (la) of trigonus
in outline. Therefore, it is difficult todistinguish lwbayaslzi fron1 trigontts by
the outline. Subtrigonal and subelliptical forms predominate in the Laos
specimens. but there may be Yariation
to some extent.

,__....
IOmm

Text-ligure 2. The variation of shell-outlines of Laos specimens
after HoFFET (1937) Plates I, II and III.
l. a. b. T. trigmtus HoFFIOT, a is the outline of the holotype.
2. T. kobayashi JIOFFET.
3. a. b. c. T. [aotiae HOFFET.
-1. a. b. T. diversicostatus HoFFET.

B) Surface ornamentation\Vhether kodairai type ornament covers
all the surface or not has been
noted, but there is tolerable variation.
As shown in Text-fig. 3, the ornaments
are classified into three types wheresuzul?ii type (b) of the upper Naktong

and Wakino series is intermediate between kodairai type ornament (a) of thelower Naktong series and malsumotoi
type (c) of the Gosyonoura.
The ornament of the Laos specimens
indicates the last stage. Namely, kobayashi and !aotiae are similar to kodairai

Yoshihisa 0 TA

100

V Systematic description of
Trigonioides in the ·wakino
and Gosyonoura formations.
A. Wakino group

Text-figure 3. The typicalornaments of Trigonioides.
a. Kodairai type ornament.
b. Suzukii type ornament.
c. .Uatsumotoi type ornament.

type. but they lack reversed V-shaped
ribs in anterior. In trigonus radial andconcentric costae become nodose near
their intersections. DilJersicostatus has
extraordinarily developed irregular ribsin the posterior.
IV New classificationof Tri gonioides
This genus \vhich has constantly
characteristic hinge teeth is classifiable
by ornament as follows :1) Kodairai type ............ T. kodairai2) Su zukii type ...................... .
.... T. paucisu!catus suzukii n. subsp.
3) Paucisulcatus type ................. .
. . . . . . T. paucisulcatus paucisulcatus4) Il1atsumotoi type ...... T. matsmnotoi
5) With nodes at intersection of radialand concentric costae .... T. trigonus
6) f{odzirai type but lacking them inanterior .... T. lwbayashi ( = T. laotiae)7) Extraordinarily developed irregularribs in posterior .... T. diMrsicostatus

The Wakino subgroup in N. Kyusyu
was subdivided by the writer into thefollo\dng formations in descendingorder:
Shimonoseki subgroup---1disconformity--"1. Upper W akamiya
formation
3. Lower Wakamiya
formation
Wakino2. NyoraidaI
subgroup
formation
1. Sengoku
formation---clino-unconformity--Paleozoic Aida group
T. paucisulcatus suzukii occurs with P.
licatounio naktongensis multip!icatus, Bro·tiopsis kobayashii and Viviparus sp. atllata, Yahata-city. This suzukii bed belongs to the upper formation as confirmeel by the stratigraphy and paleontologyof Plicatowzio. It is noted that conjoined valves predominate and the arrangement of Brotiopsis is irregular in theupper formation.
Family Trigonioididae Cox, 1952
Genus Trigonioides KoBA YASHJ
and Suzt:KJ
1936. Trigonioides KoBAYASHI and SuzcKI,
japan. four. Ceo!. Geogr., Vol. 13, p. 248.

1937. Trigonioides, HOFFET, Bull. du Sen'. giol.
de /'lndochine, Vol. 24. p. 8.

1938. 1'rigonioides,

MATSt:~JoTo, four. Geol.
Soc. japan, Vol. 45. p. 15.
1940. Trigonioides, St:ZUKJ, Japan. ]our. Geo/.
Geogr .. Vol. 17, p. 228.

363.

Trigonioides and its classification

1941. Trigonioides, KoBAYASHI and

SuztrKt,

Bull. Geol. Inst. Mancl10ullllo. No. 101,
p. 78.
1955. Trigonioides, Cox. Cl'o{. Mag.. Vol. 92.
p. 348.
1956. Trigonioides. KoBAYASHI, Japan. four.
Ceo{. Geogr., Yo!. 27. pp. 80-91.

!\lost distinguishing characteristics ofthis genus are in the surface ornamentation and hinge nature. The surface
is usually marked with V-shaped ribs on
the line across the umbo. Posterior ribs
are generally thicker than anteriorchevron ribs. An10ng the former there
are extraordinarily stout ones. The ornaments in anterior and posterior areas
are fairly variable among species. The
hinge teeth consist of regularly crenulated pseudocardinal teeth and posterolateral teeth.
Trigo11ioides differs from those of
Trigoniidae and Unionidae in the hinge
nature. In the lack of a bifid mecl ian
cardinal in the left valve, this differsfrom Trigoniidae. Supposing that thelateral tooth of Trigoniidae has been
atrophied, however, the dentition of T.
matsumoloi becomes similar to that of
Scabrotrigonia. On the contrary, Coxemphasized that the dentition of Trigonioides is similar to that of Castalia.
However. as KonAYASm pointed out already. Castalia has unionid feature in
the irregularity of arrangement andcrenulation. This is also similar to thehinge of Nippononaia. but differs in thecomposition and arrangement of teeth.
The divergence of pseudocard inal teeth
in Quadmla and Plagiolopsis seems alsosimilar to that of Trigo11ioides but theformer two are entirely different fromthe latter.
The opinion on the taxonomic positionof Trigonioides does not agree between
Cox (1955) and KoBAYASHI (1956). KonA·
Y ASHI stated that the hinge of Trigoni-

101

oides is more similar to trigonid thanto unioid. while Cox referred it to theUnionidae, paying attention to the persistent hinge in numerous trigonids.
In agreement with KoB.-\YASIII (1956) thewriter claims that Trigonioides must belong to the family Trigonioididae by its
hinge nature.
Hoffetrigonia was erected as a new
genus by SuwKr (1940) by the reason
that their outline and median tooth inthe Laos specimens differ from those of
the japanese and Korean specimens.
However, KorL-\YASllt (1956) proved Hoffetrigonia to be synonymous with Trigonioides by the reason that they are notdistinct in the outline and hinge nature.
I11atsumotoi and paucisu/catus are identical with the Laos specimens in the hinge
nature. Therefore KoHAYASIII's opinion
is correct.
Trigouioid!!s paucisulcat us
St:zuu. 1940. (emend)
1940. Trigonioides kodairai paucisulcatus
ZUKI, Japan. four.

Sv ·Ceo/. Geogr., Vol. 17,

p. 229.

Desaiption :-Shell medium, subtrigonal. transversely ovate in outline andsubelliptical. Ligament external: pedal
scar under strongest tooth (2a or 3a) ineach valve fairly pronounced. Ornamentof median area typical of the genus,
but anterior and posterior ones are intermediate between kodairai and matsumotoi. Hinge well developed, characteristic of the genus:
5a
3a
1
3b
(4a)~al'a(l'b)
2b--4bwhere brackets indicate high variability,
even the tooth being nullified. 4a low
and weak, lower side only crenulated ;2a strongest, crenulated on both sides
and oblique to hinge margin (ca. 60'):
l'b very small below the beak; 2b and4b not protuberant as an independent

102

Yoslzihisa OTA

tooth but form a wall of a groove for3b and they are fairly elongated but low.
and each crenulated only on one side.
Comparison :-·This species is fairly
variable in outline and ornamentation.
The Wakino specimens are, howe\·er, deformed. The ornament of paucisulratus
suzukii is intermediate between kodairai
and matsumotoi (Text-fig. 3b). Its ornament somewhat varies in anterior. The
ornament happens to disappear in theanterior and median area. The Siragi
specimens are remarkably effaced. Originally Suzt:Kr (1940) described it as asubspecies (kodairai paucisulcatus), but
the writer considers that it is betterto be distinguished from lwdairai as anindependent.
Trigonioides paucisulcatus suzukii
0TA, new subspecies
Plate 11, Figures 12-20.

Description :-Shell medium in size,
subtrigonal or subelliptical in outline:
ribs 3 or 5 in number in umbonal andmedian area, forming fine elongated Vs
pointed ventrally. Ribs about 18 in anterior area, in reversed \'s appear fromumbo: their angle more than twice (120"-130°) as large as posterior ones lea.
60'): anterior ribs generally narrower
than posterior ones: posterior ornaments
vary fairly extensively, but generally
consist of about 11 reversed V-ribs.
Observation :-Reversed Vs tend to become obsolete from median to anterior
margin, while concentric costae appear
strong as they procede to ventral margin
or the reversed V-ribs have a tendency
to become more or less zig-zag ribs inanterior. Another set of irregular ribsin posterior are sometimes branching
toward ventral margin.
Comparison:-This subspecies is simi-

lar to Nipponmraia ryosekiana St:zuKr in
ornamentation but differs from the latter in the hinge and anterior and posterior ornaments. T. matsumotoi resembles this species in the hinge. but they
disagree in posterior ornament.
Ocwrrence :-Lower part of upper Wakino formation at Hata. Katsuki-machi,
Yahata-city, Fukuoka Pref.
B.

Gosyonoura group

According to MATsu~!OTO (1938), Gosyonoura Island consists mainly of theGosyonoura group and partly of thellimenoura group. and the Gosyonoura
is Gyliakian in age. T. matsumotoi is
generally found as conjoined valves andthey are irregularly disposed in thefossil bed (ca. 0.5 m thickness) of thecoarse sandstone. This occurrence isnegative for long transportation. Thisfossil bed contains no marine fossil but
Viviparus (?) sp. is rarely found in it.
Trigonioides matsumotoi KoBAYASHI
and SczuKJ, 1940
Plate 10. Figures. 1-15.

Trigonioides kobayashii MATSDIOTO,
four. Geol. Soc. Japan, Vol. 45, p. 14. Pl.
2. fig. 2.
19:10. Trigonioides matsumotoi KonA YASIII andSIJZUKI, Bull. Geol. Ins/. illauclloulmo.
No. 101. p. 78.

1938.

Descriptio11 :-Shell medium. ovately
subelliptical, regularly rounded in lateral
margins. Surface marked by radial ribs,
every two of which meet together, forming an acute V on the line throughumbo: a set of simple ribs composed ofabout 8 on anterior and 3 on posterior;another set of ribs branching off toward
antero- and postero-dorsal margins fromobtuse umbonal ridge: some of themyielding a few regular Vs in adult stage.

363.

Trigonioides and its classification

Hinge teeth well developed:

228. Pl. 24. Figs. 1 -4.

(5a)
3a
la
(lb)
3b
(4a)
2a
l'a
(l'b)
2b
4b

where brackets indicate high variability.
4a along hinge margin degenerating:some fairly strong and crenulated on
both sides. but most of them are weakor undeveloped. 2a strongest. crenulated on both sides. and oblique to hinge
margin (ca. 30'). l'a next strongest.
crenulated on both sides. and oblique tohinge margin (ca. 60°): l'b fairly developed or undeveloped : even when developed. it is small. crenulated on bothsides. and half as long as 2a: when not
so much developed. it has small nodelike denticles in two rows: 2b and 4b
rather degenerating, small and crenulated only on one side. even \Vhen developed.
,Heasurement:

LengthHeight1500

44 rnrn

38 mrn

1502

34

1501
1516
1503
1504

38
42
19
22

Gu. K

..

..
..
34 ..
19 ..

31

38

.

..
..

17

..

Comparison:-This species is similar
to paucisulcatus suzu!?ii but differs inanterior and posterior ornaments. It resembles Nippono11aia asinaria REESIDE(1957) in the ornament. but they can be
distinguished by the hinge nature.
Occurrence :-Upper Gosyonoura groupat Kyoclomari. Gosyonoura Island. Kumamoto Pref.
Trigonioides paucisulcatus
paucisulcatus SuzwKI, 1940
Plate 10. Figure 16.
1940.

Trigonioides kodairai paucisulcatus SvzL· ·Japan. four. Geo!. Geogr., Vol. 17. p.

Kl,

] 03

Description :-Shell medium, transversely ovate and subelliptical in outline.
Beak submedian. fairly large. prosogyrous, more or less incurved. Hinge
teeth characteristic of the genus. Sur·face with suzukii type of ornament inumbonal and posterior areas. which disappears in anterior and median areas:
concentric costae strong near ventral
margin.
Comparison:-This differs from kodai·
mi. paucisulcatus suzukii and matsumotoi
in ornamentation. The ornament is effaced in various degrees.
Occurrence :-Rarely occurs with ma/sumotoi in upper Gosyonoura group at
Kyodomari, Gosyonoura Island. Kumamoto Pref.
VI

Phylogeny

The development of the hinge andornaments is brought together withstratigraphical evidence into consideration .
A)

Hinge nature

The hinge of Trigonioiades is fairly
constant. although there are some variations in the median and lateral teeth.
Generally, the lateral teeth indicate thedegenerative features.
1) On the variation of the hinge
teeth of the right valve.
a) In suzuldi. lb is not yet developed
but the median tooth is simple.
b) In ma/sumotoi. 1b indicates the primitive feature of development. Namely,
among the specimens, lb is un-developed or a small independent tooth.
c) lb is more developed in the Laos
specimens than in matsumotoi. but it
seems to have some yariation in HoFFET's
figures. 5a is a fairly constant toothYoshihisa OTA

104

but its development is fairly variable.
3a and la are constant teeth.
(2) On the variation of the hinge
teeth of the left valve.
a) In suzukii, l'b becomes an independent tooth. Namely, all suzukii specimens have it as a tooth but its development is fairly variable.
b) l'b of matsumotoi and Laos specimens is same as that of suzukii but
the development is fairly variable.
c) 4a is rather degenerating. Namely,<1a of suzukii appears as a small toothalong the hinge margin, but in the Laos
specimens, 4a is undeveloped and two
rows of small holes are seen on thehinge plate. 2b and 4b tend to degenerate. 2a and l'a are constant teeth.
B) Ornamentation
As illustrated already, the ornamentsof Trigonioides can be divided into a)

kodairai type, c) matsumotoi type, andb) suzukii type which is intermediate
between the two others. When one takes
note on ontogeny, each type is a continuous series by the intermediate form.
Paucisulcatus paucisulcatus is specialized
from suzukii type. The upper Naktong
subspeciesindicaets an intermediate form
between paucisulcatus suzukii and paucisulcatus paucisulcatus. Its ornament disappears from anterior to median invarious degrees. Some specimens ofmatsumotoi type indicate also a similarfeature to kodairai type even in theadult stage. As already illustrated, theLaos specimens indicate the ornamentof the last stage which is fairly different from the above three types (a, b
and c). However, their umbonal ornament is rather similar to kodairai type.
The above facts on phylogeny may be
explained in the manner as shown in
the table (p. 60).

Table 5howing the phylogeny of the Trigonioides.

~,.

Trfgonlol~
0

kodalraipaUCISUI~(!fUS

SUZU f1c.au~frtca]us
auc sulcatusmatsumotoi

Eo-Cretaceous
Early
Low.
Noktong•·. ·..

Late
MiddleUp.Noktong Low.Siragi
Up.Wakino---·. ...............

kobayashi
trigon us
divers icostatu s* Terrain rouge cretace de Muong-Phalanc.

Neo-Cretaceous
Early
Up.
Gosyonoura-·.·.· .

~......
·.

Late
Laos*

Trans. Proc. Palaeont. Soc. Japan, N. S .. No. 34, pp. 105-110. pls. 10, 11, June 15, 1959

364.

ON THE ·• NIPPONONAIA " FROM THE LOWER CRETA CEO US
WAKI~O SUBGROUP, NORTH KYUSYU, JAPAN.

(Studies on the .lviolluscan Fauna of the Cretaceous
lnkstone Series. Part 3.)*YOSHIHISA OTA
Fukuoka Liberal Arts College.
"F$8i!l!:>f,~!ffJ!ll!mMi!11"XiPJxmonaia" IC:"?'.'"f:

L.R. Cox fW±c'J't-H'i~cO)~
ornament. outline. hinge !'!j\! Nippononoia l:.i]:)'t"P7.>. fl\ [., hinge, ornament L'ffi:% t,;};, I) Nippmtonaia 0.:> diagnosis c ~~rc:.:;t-3& [.,t.;•. '· Nippo11011aia <D~l:t~*lil.f:lijf1'1jij"Cf.f\ i:. ~1<"t>~~ [.,"( t';.,. Vf'?"(~fl{:r.fijjk O.:>i~gn'ib7.>n:~·@lt;t "Nipponollaia".!: Vt'i{Jlj1~t'. llb6!ff"F$fvHJ·IS 2 ffrf;li~Jc~[.,t:. x ornament 't'?f.'i't!i:.J: <{l:l;.z. Trigonioides ~O.:>I§'Jit?.\~llJJ!Sb·l:.[.,t:.
~~=~l~"t7.>11661JlrFfflllmO.:> t Cl)li.

In 1941, SuzuKI erected a subgenus,
Nippononaia. with an internal and external mou Ids.
However, whether the
specimens came from the Lower Cretaceous of Sanchu graben in Kwanto
mountains or Katsuraga,va basin ineastern Shikoku was a quesion. They
were unfortunately gone by a fire in
the Second Great War.
Lately I collected several specimensfrom the Lo\ver Cretaceous Wakino subgroup. They are similar to Trigonioides
kodaimi KoBAYASHI and SuzuKI in theornament and Plicatounio kwamnonensis
0TA in the hinge nature. Namely, they
have intermediate features between
Trigonioides and Plicatowzio but probably
more related to Nippononaia ryoseleiana
Suz~;Kr in both respects.
When thehinge is unknown, one can not distinguish them from T. kodaimi. Therefore these Wakino specimens have once
been taken for T kodairai but its type
locality is the lower Naktong formation----------* Received July 26, 1958; red Feb. J.!. 1959

at Hiroshima University.

at Shinshu, Korea. The specimen (Cox,1955. Text fig. A; KoBA Y;\SHI. 1956. Pl.
V. Fig. 3; 0-rA. Pl. 6, Fig. 11) which
was disputed by Cox and KoBAYASHI
was an internal mould collected by mefrom the lower w·akino formation. Coxreferred it to T. kodairai. and KoBAYASHI
to Plicatozmio naktongensis multiplicatus,
if not a Nippononaia. It is difficult todecide whether the specimen belongs to'' Nippononaia" or Plicatozmio, for its
surface ornament can not be seen. I
have once identified it with T. lwdairai,
but now it is ascertained that the Wakino specimens can be distinguishedfrom Trigonioides in the hinge nature.
I want to describe here two new species from the lower \Vakino formation,
which are provisionally referred to·· Nippononaia ", although much obscurity is attached to the hinge nature oftrue Nippono11aia and its taxonomic position is ambiguous.
Before going further. I wish torecord his warmest appreciations toProf. T. KoBAYASHI of the University
105

lOt)

Yoshiltisa OT;lof Tokyo, for his continuous encouragement, and express many thanks to_
Messrs I. 1-l.-\YA~II and A. ToKt:YA~IAof the l:nh·ersity and l\Tr. 1\1. NAKA:'\oof the Hiroshima University and Assist.
Prof. H. Ho:-;To of the Fukuoka Liberal
Arts College at Tagawa for their kindhelp.
IDistinction among "Nippononaia",

Trigonioides and Plicatounio.
A.
The difference of ·• NiPJ>o·11011aia" from Trigonioides on one side,from Plicatounio on the other. One caneasily distinguish the last from thetwo others in outline and ornament.
Namely. Plicafonnio is distinct fromthem in its posterior radial plications
and transversely elongated outline. Pli·catounio is more or less similar to "Nippononaia '' in the subquadrate or subtriangular outline.
B. It is not always easy to distinguish ·• Nippononaia ·• from Trigonioides as
they resemble in the outlines and ornaments. As the result of this study, it
was found that the two genera can be
distinguished by the hinge nature.
More precisely, the median teeth are
more developed in Trigonioides than in"Nippononaia •·. as formulated below:".Nippononaia "
3a

(3b)
(1')

5b

2b --1b

Trigonioidcs
(5a)
3a
la
(lb) 3b(4a)--2a--l'a- (1'~ 2-b- 41)

where brackets indicate such great
variability that the teeth in brackets
are sometimes totally absent. Furthermore. the difference between them exists
in the disposition of hinge teeth. Two
pseudocardinal teeth are subparallel tothe anterior hinge margin in the !eftvalve of " Nippononaia ''. while in thatof Trigonioides they are four in number,diverging from beak to the anterior
hinge margin with angles of 0 ', 30•. 60°
and go• (Text-fig. A).
The hinge plate of "Nippononaia" isnarrow \vith slender teeth and that of
Trigonioides wide with stout dentition.
Suzt:Kr in his second paper (19,13) took
1rue Nippononaia as a subgenus ofPlicatouuio instead of Unio because of
its hinge nature indistinguishable fromthat of Plicatounio. .. Nippononaia" issomewhat similar toP. lm•mtmonensis 0TA
0958) in the hinge hut fairly different
from P. nal?tongensis which has many
unionid features in the hinge nature.
II Comparison between American
species of Nippnno1wi a and"1Vippononaia ,, of the
Wal<ino subgrOUJ).

REESIDE (1957) reported the find of
Nipponrmaia in the Lower Cretaceous ofColorado, North America. Comparing"Nippnnonaia" of Wakino with REEsroE'S,
the follo\ving differences can hardly beoverlooked.
1) In the composition and arrangement of the teeth, they are very muchalike. but RF:F:SIDE·s teeth are not distinctly crenulated as those of Wakino
form.
2) REEsmE's appears rather smoothaccording to his Text-figure 2 (REESIDE,
1957. p. 652), but the '\Vakino form has
distinct crenulation on the ventral
margin. However. 1 can not make surewhether the ventral margin of REF.:sroE'sis crenulated or smooth as nothing isstated.
3) In ornamentation REEsloE's is moresimi Jar to Trif{onioides matsumotoi KoBAYASHI and Sczur-:r than Nippononaia

364.

"Nippononaia" from the Lower Cretaceous

107

4a

Text-figure. A. Hinge-structure of ·· :Vippouonaia ''. Trigouioides and Trigonia.
1 a. "J'iippononaia" zcakinoensis (?) OTA, n. sp.
1 b. "Nippononaia" sengokuensis 0TA, n. sp.
Lower Wakino subgroup. N. Kyusyu. japan (based on an artitidal cast madefrom a natural mould.)
2. Trigonioides paucisulcatus suzukii OTA n. subsp.
Upper Wakino subgroup, :\. Kyusyu, Japan (based on an artitit:ial wst madefromea natural mould.)
3 a. and 3 b. Trigonioides matsumotoi Ko13A YASIII and St:zcK 1
Upper Gosyonoura group. Amakusa. Japan (based on an artificial cast madefrom a natural mould.)
4 a. Trigonioides kobayashi 1-loFFET
Senonian Bas Laos (based on a left vah·c)•I b. Based on HoFFET (1937) Text-fig. (P. 10. fig. 3)
5. Neotrigonia margaritacea LA~IARCK
6. Scabrolrigouia scabw (LAMARCK)
Based on the Text-figs. 20 and 22 (p. 25) published by LEBKUC!II'\ER (1932).

ryose!?iana and Wakino form.
As the difference between REE:51DE's
form and Wakino one is distinct, I
consider at present that the former
should be excluded from "NiPPononaia"
in my mind.

III Description of Species.

Genus ·• Nippononaia" SuzuKI, 1941

"Nippononaia" u.:akinoensis 0TA,
ne\"v species
Plate 11, Figures 1-7. 11.

Yoshihisa 0Til

108

Description:-Shell medium in size,transversely elongated, subelliptical in
outline. subequilateral, regularly rounded in anterior and subquadrate in posterior: dorsal margin broadly arched.
subparallel to ventral margin which isslightly curved. Test fairly thick. Beakfairly prominent, prosogyrous. more orless incurved, placed at about two-fifths
to submedian and fairly projected above
hinge line. Surface ornamented withmany V-shaped ribs crossed by concentric growth lines: radial ribs fine andclosely set in middle: several middle
ribs (6-8) converging to form acute Vs
on a line through beak: each side ofthem regularly ornamented with reversed V-ribs: anterior ribs about 18-20
including middle V-ribs smaller andmore numerous than posterior !14-16).
Hinge well developed; cardinal teeth
relatively short, narrow and finely crenulated: lower one stronger than upper:
lateral teeth fairly long, lamellar, finely
crenulated, but weak and Io·wer thananterior ones. Internally, ventral margin crenulated especially in posterior
half.

only on one side. It is a tendency for
3a or ~a to branch off near beak. The
branching tooth can be seen as arrangements of nodes under the beak.
The ornament of the anterior area isvariable. Namely, anterior ribs become
weak in adult stages, while radial ones
are sometimes replaced by concentriccostae. In the anterior area ribs are
sometimes zig-zag or irregular.
Comparison:-This is most similar toN. ryosekiana SuzuKI in outline, ornamentation and hinge nature.* However.
"N." tcaki11oensis differs from N.
1·yosekiana in lateral teeth and posterior
ornament. This new species is alsosimi Jar to Trigonioides kodairai and T.
paucisulcatus suzukii, but differs in thehinge nature. As already discussed,
this differs from N. asinaria REEsJDE inhinge and ornament.
Occurrence :-Lower Wakino formation
at Rikimaru, l\liyata-machi. Kurate-gun,
Fukuoka Pref.
"Nippononaia .. sengokuensis 0TA,
new species
Plate II. Figures 8-10.

llfeasureml'lz/ s:

Height
-----

WJ.S

5057
506(1
5051
5086

26mm

48
4742

31

24
20

Occurrena :-Lower Sengoku format ion
in Wakino subgroup at Rikimaru, J:vliyatamachi, Kurate-gun, Fukuoka Pref.
Observation:- The hinge nature andsurface ornament vary considerably:
4a, 3b and median tooth are developed
in some but not in others. Namely, 4aand 3b are degenerative. Even whendeveloped, they are smaller than theothers and a little convex and crenulated

Description :-Shell rather small, oboval, moderately convex. subequilateral,
rather regularly rounded on both sides,
ventral margin rounded. Beak small,submedian, prosogyrous. more or lessincurved. Numerous ribs arranged as
usual in tcakinoensis.
Hinge teeth
identical with those of the species, but
the angle of hinge margin is smaller.

* I showed these specimens of "N." wakitzoensis to Dr. K. SuzuKI who erected 1Vippono·naia. He said that the Wakino specimens
arc so similar toN. ryosekiana in all respects
that they arc referable to his subgenus, notwithstanding the fact that the two species
disagree in the number and crcnulation oflateral teeth.

364.

.. Nipprmonaia" from the Lou.Jer Cretaceous

I Length-- --J11easuremenls:--·\VI. SHeight

--

5053

19 mm

5050

22

5031

18

17 mm
21
17

Comparison:- This is distinguishedfrom ''N." zmkinoensis and "N." ryosekiana
Suzt:KI by small size and oboval outlineof the shell. T. kodairai was originallydescribed from lower Naktong and'Vakino series by KoBAYJ\SIII and Suzt;KJ.
The Wakino specimen (KoBAYASHI and
St:zn:J, 1936. PI. 29. Fig. 13) which theydescribed is incomplete in ornament.
and its hinge nature is also not distinct.
Therefore I cannot accurately determine
whether it is T lwdairai or '' N." sengokuensis. But I presume that it isprobably "N.'' sengolme11sis as suggested
by its oboval outline and small size.
Occurrence :-Same as the preceding
species.
Heferenccs
Cox. L. R. (1954). ~otes on the Trigoniidae,
with Outlines of a Classification of the
Family. Proc. 11Iat. Soc. London, vol. 29,
Pts. 2 & 3.
- - (1955). On the Affinity of Tri;.;mzioides
and Hoffetrigonia. Geo/. Mag .. I•'o{. 92.
Co;-.;RA!J, A. (1853). s~-nopsis of the Family
Naiades. Proc. Acad. Nat. Sci. Philadelphia.
Vol. 6.
DAVIES. A.M. (1953). Tertiary Faunas. vo!.
1, London.
HOFFET, J. H. (1937a). Sur le Genre Trigoni·oides, l\Iutation genetique stable du Genre Trigonia. C. R. des seances de t.4cad.
des Sci. Paris, 1937.
- - (193ib). Les Lamellibranchis saumatresdu Muong Phalane (Bas Laos). Bull. SertJ.
Ceo/. /'llldochine, Vol. 24.
KOBAY,\SHJ. T and Sezn:J. K. (1936), .!'\on·109

marine Shells of the Naktong-\Yakino Series. Japan. four. Ceol. Ceogr., Vol. 13.
- - and - - (19H). On the Occurrence ofTrigonioides in Southeastern .Manchoukuo.
Bull. Ceol. Ins!. ilfandwukuo. No. 10 I.
KoBAYASlll. T. (195·1), Studies on the Jurassic Trigonian in Japan. Pt. 1. Preliminary
Notes. Japan. four. Geol. Geo~:r .. Vol. 25.
Nos. 1-2.
- - and MoRJ. K. (1955). The Vaugoniinae
from the Kitakami 1\lountains in North
Japan. On the Jurassic Trigonians injapan. Pt. 3. Ibid .. Vol. 26, Nos. 1-2.
KonAYASJJI, T. (1956). On the Dentition of
Trigo11ioides and its Relation to Similar
Pelecypod Genera. Ibid .. Vol. 27, No. I.
LEnKCCJJ:'IER, R. (1932). Die Trigonien desSuddel'ltschen Jura. Palaeotogr., Bd. 77.
Mt\TSt::I.JOTo. T. (1938). Geology of the Gosyonoura Islands. Amakusa, with special
Reference to the Cretaceous Stratigraphy.
four. Ceo!. Soc. ]apa11, Vol. 45.
- - et al. (1954). The Cretaceous System in
the Japanese Islands. ]apa11. Soc. Promoliou. Sci. Research. Tollyo.
PH ASH AD. B. (1919). Studies on the Anatomy
of Indian 1\Iollusca. No.3. Records bzdimz
J"!us .. Vol. 16.
REESIDE, J. B. (1957). Non·marine pelecypod(Nippo11onaia asinaria) from the Lower
Cretaceous of Colorado. Jour. Pal.. Vol.
31. No.3.
SL'ZtJKJ. K. (19·10). !\on-marine .Molluscan Faunule of the Siragi Series in South Tyosen.
fapau. four. Geol. Ceogr., Vol. 11.
- - (1941), A new naiad, Unio (Nipponouaia)
ryosel~iana, n. subgen. and n. sp. from theLower Cretaceous of Japan. four. Ceo/.
Soc. Japan. Vol. 48.
- - (1943). Restudy on the ~On·IVIarinc Molluscan Fauna of the Rakuto Series in
Keisho-do. Korea. ] our. Slligen Ka!!aku
Kenkyu·Sho. Vol. 1, No. 2.
- - (1949), Dcvelopement of the Fossil Nonl\Iarinc lVIolluscan Faunas in Eastern Asia.
fa/J(ln. ]our. Ceo/. GeoJ:/'., Vol. 21.
THIELE. J. (1934-35). Handbuch der systematischen Weichtierkunde. Bd. 2. lena.

110

Yosltiltisa 0T.4

Explanation of Plate 10
All natural size

Trigonioides matsumotoi KoBAYASIII and SuzuKI ...................................... Page 102
Fig. 1. Right internal mould. showing the hinge.
Figs. 2, 3. 4. 5. 6, and 7. Left internal moulds.
Figs. 8, 9, 10 and 11. Right internal moulds.
Fig. 12. Right external mould, showing the posterior and median ornament.
Fig. 13. Right plaster cast.
Fig. 1-1. Right external mould, showing an anterior and median ornament.
Fig. 15. Right artificial cast. showing the anterior ornament.
Trigonioides jxmcisulcatus poucisulcatus SczuK 1 ........................................ Page 103
Fig. 16. Incomplete right internal mould, showing the anterior ornament.
Upper Gosyonoura group at Kyodomari, Gosyonoura Island, Kumamoto Pref.

Explanation of Plate 11
All natural size except Eig. 9 ( x2)"Nippononaia" wakilzoensis 0TA, new species .......................................... page 107
Fig. 1. Right internal mould. hololype.
Figs. 2a and 2b. Plaster cast showing the surface ornament.
Figs. 3 and 4. Internal moulds of an immature right valves, showing the outline of
the younger stage.
Fig. 5. Plaster cast of an incomplete right valve.
Fig. 6. Piaster cast of an incomplete left valve.
Fig. 7. External mould of a right valve, showing disappearance of the anterior radialribs.
"A'ippononaia" sengokuemis OTA, new species ........................................ Page 108
Fig. 8. Left internal mould. holotype.
Fig. 9. Right internal mould.
Fig. 10. Plaster cast of an incomplete right valve.
"Nippononaia '' wakinoensis OTA. (?)
Fig. 11. Right internal mould.
~II above specimens: Lower Wakino subgroup at Rikimaru, Miyata·machi. Kurate·gun, Fuku·
oka Pref.
Trigonioides paucisulcatus suzukii 0TA, new subspecies ................................ Page 102
Fig. 12. Internal mould of the bivalve. holotype, showing the hinge.
Fig. 13. External moulds of the paratype bivalve, showing the surface ornament.
Fig. 14. Right internal mould.
Figs. 15 and 16. Bivalve internal moulds. showing the hinge.
Figs. 17 and 18. Hight external moulds.
Fig. 19. Left external mould.
Fig. 20. Dorsal view of an external mould of a bivalve.
Upper Wakino subgroup at Hata. Katsuki·machi, Yahata·city, Fukuoka Pref.

OTA: Trigonioides

Plate 10

9

lU

14

0 TA:

Trigonioides and NiPPononaia

Plate 11

8

20

18

Trans. Proc. Palacont. Soc. Japan, N. S., No. 34. p. 111. june 15, 1959

SHORT NOTES
4.

TRITICITES THALMANN! SAKAGAl\II AND 01VIATA AND
SCHWAGERINA GUEMBELI OMENSIS SAKAGAMI AND
Q}fATA. NEW NA1\IE FOR T. INTERMEDIA AND
S. GUE1WBELICON!PACTASUMIO SAKAGAlVII
Department of Geology. Hokkaido Gakugei University

andTOSHIKAZU OMA TA
l\'lizuho Middle School. Tokyo

Prof. Dr. H. E. THAU.IA['.;:'-l has kindlycalled attention to two homonyms in ourpaper (S. SAKAGAMI and T. 0:-.L'\TA, 1957,

gerina compacta (WHITE, 1932) according
to DmmAR and SEI:'>il'ER, 1937, Univ.
Texas Bull. 3701, p. 645 (for Triticites
compactus vVniTE, 19:~2). Therefore, newnames Triticites tha!mamzi SAK.\G,nll ando~. A TA and Schwagerina guembeli omens isJapan., ]our. Geol. Geogr.. val. XXVIII, no.
4. pp. 247-264. pis. XIX-XX). Namely, 1)
our new species Triticites intermedia on p.
253 is preoccupied by Triticites jigu!ensis
RAt:SER, 1938, var. intermedia SLYKOWA,
1948: and again by T. (Jigulites) intermedius RozovsKAJA, 1950: from the up-

SAKAGA~II

and o~IATA are here proposed
for the homonyms T. intermedia SAKAGA:>.II and 0~1ATA and S. guembefi COmpacta SAI:AGAMI and 0MATA, respectively.
Our thanks arc extended to Prof. Dr.
Hans E. TIL-\DIA:'-i"' of Stanford University for having pointed out this error.

per Carboniferous of USSR. and 2) our

Sclu.mgerina guembeli compacta n. subsp.
on p. 258 is also preoccupied by Schwa-

111

112

NEWS
Session. International Geological Congress c fii)II,H:.fmflli ~.h 7.:, International Paleontological Union O)~ft'Ct:t.(kO) r ~/' .?i.:."?\..•"CiliiMiifl~.fif.d?.h7.:,.::.cl::ts:~t..:"

@ XXI

A.
B.
C.

Paleoecology: l'dethods and principles: examples of paleoecological syntheses.
Paleobotany: Calcareous algae, especially the Solenoporaceae. Stromatoliths.
Micropaleontology: ~icsozoic and Cainozoic pelagic Formaminifera and their stratigraphical importance.
D. Invertebrate paleontology: Interpretation of primitive fossils and intermediate groups.
E. Vertebrate paleontology: The adaptation of vertebrates to terrestrial and aquatic
environments: passage-forms.
F. Zoological nomenclature.
G. Other subjects: Communications of general interest. or contributing important new
data.
Congress O)j\'(:*fl(;::"?l•"CU:4JllBJHj'O) Second Circular ~~Ji.~~;ht..:~·,o@ 1959 ~ 8 !1 30 13 .J: I) 9 fl 12 B l.:.;bt..: I) New York -c: IJIH!li ~Jt
International Oceangraphic
Congress
Paleobiogeography t.:.~ L. "C(;;O) panel discussions fl'·1rts::b.ho .::./:: 1.:.ts: ~f..: (* QJ(;J:ffl.:(Ei 'Ci.:.lfj/(f,'O)i'}t}ji L. "( \.. . 7.:, {,)-cPanel I. (9 Sept.) Basis of paleobiogeography (KstAZKlEwtcz. discussion leader)* William S. von ARx-An experimental approach to paleooceanography (a talk will bepresented and motion pictures will be shown)* RICHARD R. DOELI.-Paleomagnetism
E. MoNTA7'ARo-GALLlTELLI-\Vest Mediterranean marine paleobiogeography
R. Th. HECKER. A. I. OssJPOYA. and T. N. BELSKAYA-Pakobiogeography of the Fergana
Gulf in the Paleogene Sea* John IMBRIE-Evolution of major adaptive invertebrate types
E. A. lvA:'\0\'A-Marine paleobiogeographr of the Russian coal fields
Teiichi KoBAYASHJ-Kecroplankton and other dispersal artifacts* Marian KsiAZKIEWJCZ-Life conditions in flysch basins
G. U. LJ:\'DBERG-The dbcontinuous distribution of fishes and large fluctuations in oceanlevel
H. W. lME:-<ARD-Possible former isthmian links in the Pacific Ocean* Siemon \V. 1\Il'I.J..ER-Triassic and Early Jurassic paleobiogeography]. M. PERJ:s and ]. PICARD-Origin. distribution, and recent alterations in the Mediterranean benthic fauna* Curt TEICHERT-Evaluation of bathymetric evidence furnh;hell by marine fossils
Karl TVREKIA:-1 and Karl "rAAGI~James \V. VALEI"TJ;..:E-Marine climatic record of Northwest American epicontinental
Pleistocene* \Y. P. \VoooJH~G-Tertiary C:tribbean molluscan faunal province
Panel ll. (10 Sept.) Organic aspects of paleobiogeography as illustrated by distributionof reef-building organisms in time and space (Lr.co:-.IPTE, discussion leader)F. M. BAYER* Helen Dt;xcAN-Lower Paleozoic reefs* A. G. FJSCHER-Anthozoan growth patterns
T. F. GoRr.Au-Caribbean reefs
H.S. LADD-* Marius LECO)IIPTE-Le phimomene recifal dans Ia partie europeene occidentale du geo·
synclinal hercynian
Heinz LOWEJ:>;STAMJ\1* K D. NEWELL-\Vest Atlantic coral reefs
Ting Ying H. MA-History of the Pacific, Atlantic, and Indian ocean basinb as deduced
from growth values of reef corals
Daninele Rosst-Italian Triassic reefs* Eugen and lise SE1130LD-Foramini iera and facies: examples from the sponge bioherms
and bedded limestones in the lower :1\Ialm of south Germany
Henri and Genevieve TER:-.IIER-Bioherms, limestones and carbonate rock building organisms
john W. \YELLS-l

Panel IIJ. (11 Sept.) Major features of Cambro·Ordovician marine biogeography-a testof available methods (PAL:'-.IER, discussion leader)* Wm. B. N'. BERRY-Distribution of Ordovician graptolites
Kenneth CASTER* Alan V. Cox-Physical consequences of shifting poles or crust* Rousseau FLOWER-Ordovician faunal realms
Zofia KlELA:"l·]AWAROSKA-Late Ordovician trilobite migrations* A. R. PAt.i\IER-Early Upp;"Jr Cambrian biogeography* Reuben J. Ross, jr.-Bighorn fauna
Xils SPJELNAEs-::\Hddle and Upper Ordovician faunal patterns* H. B. WHtTTINGTo:-:-Ordovician trilobite distribution
Alwyn WILLIAMs-Ordovician brachiopod distribution© International Organization of Paleobotany (7)~ftt1~ 9 fill International Congress of BotanyQ)~Wl•l• 1959 ~ 8}) 24 I~ 1;:, Canada Q)@ ~ 10 @)Montreal "t'mlfiiU~.h.7.>.:. c t;:.t.~:...,t-:.

Pacific Science Congress :! Honolulu Q) Hawaii j;}'f."C 1961 ~ 8}) 21 E .t ~ 9})2a~b~...,"(:~•~.n~~c~~...,~.

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