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Transactions and Proceedings of the Palaeontological Society of Japan
New Series No. 6-l
Palaeontological Society of japan June 15, 1959 CONTENTS,
TRANSACTIONS Page 359. Taxodonta and Isodonta from the Upper Jurassic Sakamoto Formation in 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 79 362. 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 the Cretaceous 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. An Additional Note on the Liassic 'Cyrenoids ·• in Japan ... Itaru IIAYAMI 78 •1. Triticiles tlzalmamzi SAKAGAMI and 0:-..IATA and Sclumgeri11a guembeli omensis SAI President: Teiichi KoBAYAsHI Councillors: Kiyoshi AsANo, Riuji ENvo (Publication), Seido ENDO. Haruyoshi Fun MOTO (Treasurer), Shoshiro HANzAwA, Kotora HATAI, Ichiro HAYASAKA, Kazuo Huzioi 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 JURASSIC SAKAMOTO 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 ! In the second part of this study the Chlamys (Cit!mnys) sp. Taxodonta and Isodonta arc described. Chlamys (Radu!opedcn) ogawensis KIMURA The horizons and localities of the fossils Chlamys ( Radulopecten) nagatallensis KUHA- have already been listed in the previous TA and KI\Jl'R.'\ "Aequipeclen" mlgaris Kr:'l!l'I~A paper I,TAw IL\, 1959). T. KP.. It'HA has "Aequipeclen" kotsubu (Kl\ll'RA) described many pelecypods of these Camptonecfes sp. aff. brotnti C• >X groups, especiallv Pectinaceac, from the Camptonecfcs ? sp. ljpper Jurassic Torinosu group in Saka EoPecten sp. wa basin lKl~IURA, 19!11 & 1956). Here Varimmtssium !Jabtmokau.·eltse ( K1 \IURA) Cate!la Ih:AI.EY (1908) is promoted to the Entolium yrtfsujiense Kt:RAT,\ and KnwRA generic rank and Torinosucatella, subgen. Enlo/ium kimurai TA\ICRA. new species nov. is erected on Cat ella (Torinosucatella) Sot~wpecten kaminumensis Kr\ll'RA kobayashii. new species. Remarks are Lima (P/agioslrmza) sp. given on Somapecten ·which is very akin Lima (Ctenoides) tosana Knll.'IL\ Lima/uta rdiculata TA\JUR,\. new species to Ento/ium and has a peculiar strong angular conical tooth in the right valve The writer records his sincere thanks and a corresponding socket in the other to Prof. T. 1\nnAYAsrtl of Lhc University valve. The species here described are of Tokyo for his kind guidance and as follows: supervision of the manuscript. Thanks are also clue to Assist. Prof. T. Knn:R.\ Parallelodon i11.flatus TA:'Ifl'R,\. new species and !\'lr. I. HAL\\rr of the saJlle Univer Grammalodon takiensis KJ:\IUHA Cat ella ( Torinosucatel!a) kobayashii TA ~IU sity for assistances in laboratory works. RA. new subgenus and new species Nuculana ( Praesaccella) erinoensis K 1\1 c RA Family Parallclodontidae :Vuculana ( l'raesaccella) yatsushir01:nsis TA :'IIURA. new species Genus Parallelodon :\h:E~~: and l•luculana (!Jacryomya) stenodolichos KJ:\IL'RA \V ORTIIE:O..:, 1866 Clilamys (Chlamys) iboibo KuRATA and KI\Il'R.\ Para/lelodon injlatus T,\:...lt:RA, ne\v species *Received Aug. 30. 1958: read S..:pl. 27, 1958. !'late ti Figures. 9, 10. 54 Minoru T1LlfURA Description :-Shell medium sized for sides; posterior side depressed and or genus, elongated and oblong in outline. namented with about 13 radial ribs; with length nearly equal to twice the anterior area with about 6 radial ribs; height, strongly inflated; umbo at about very fine radial ribs present in median 1/3 or a little less from the anterior part but generally obscure; hinge typi· end, improminent. prosogyrate and in cal of Grammatodon. curved; sinus invisible on ventral side; Occurrence :-Many specimens of inter carina-like angulation passing from nal and external moulds of both valves umbo to postero-ventral corner; t"·o occur at Locs. 1, 2, 4, 5. 6, 7, 9, 11. 12, long posterior teeth nearly parallel to some being deformed. ventral margin: hinge of Paral/elodon: 4 posterior and 6 anterior teeth all short Genus Catella HEALEY, 1908 in left valve: surface probably smooth except for growth-lines. Type-species :-Grammatodon (Catella) This species is based on very inflated !at iriaN/ HEALEY. internal moulds of right valves which Generic diagnosis :-Shell equivalve, have no ventral sulcation. inequilateral, inflated. trapeziform in J11easurement s :- outline and a little produced posterior; L II umbo slightly prosogyrate, situating a holotype 43mm 19mm little anterior to center; surface orna 37mm 20mm mented with concentric lamellae or Occurrence :-Locs. l 6. radial ribs; a strong internal ridge passing from umbo towards ventral margin nearly perpendicular to hinge Family Cucullaeidae FJ:-:L.·\Y and margin; the corresponding external con ~L\RWICK, 193/, emend. striction present: hinge structure of NICOL, 1954 Grammatodo1l type. Remarks :-Subgenus Catella was Genus Grammatodon J\IEEK and eret:ted by HEALEY (1908) on Grammatodon lhYDE:-:, 1860 :Catella) laticlm•a HEALEY from the Rhaetic Napeng beds of Burma, which Grammatodon takiensis K1 ~JL:RA has a strong internal rigde and a cor responding fairly wide constriction in !'I ale 6, Figures 1, ~. surface passing from the umbo toward 1956. Gramma/odon takiensis. KI:o-.Jl'R,\, p. 85. the ventral margin. She included this pl. 1. fig. 6. subgenus in Grammatodon MEEK and Shell small to medium, strongly in- 1-L\\'uE:-:, although the concentric lines 11ated, subrectangular in outline, length in laticlaoa are almost invisible in Gram· to height about 3: 2: posterior margin matodon. longer than anterior: umbo at a third Several specimens with an external or more of the length from anterior, a constriction and an internal ridge were little prosogyrate and incurved; fairly collected from the Upper Jurassic Saka distinct carina running from umbo to moto formation. In hinge structure it postero-ventral margin, but an anterior agrees with Grammatodon inclusive of one weak; surface covered by fine con Latella. In these specimens, however, centric lamellae but obscure on lateral radial ribs are closely spaced and some 359. Taxodonta and Isodonta from the Upper jurassic concentric wrinkles weaker than the ridge and the corresponding external radial ribs and obscure in some forms. constriction and secondarily the exter G. TRowsso" (1951) described Gram nal ornaments, the writer promotes matodon (Cate/la) siuuatus and G. (C.) Catel/a HEALEY to the generic rank. subrlwmboidalis from the Katslosa bed Torinosucatella is erected as its subgenus of Hoganiis Series of Sweden whose age which is represented by C. (T.) lwbayaslzii is uppermost Sinemurian or its transi from Sakamoto formation and includes tion to Pliensbachian. The former is G. (C.l sinuatus TRnEossoN (1951). ornamented with radial ribs and con· centric wrinkles as the Sakamoto form. Subgenus Torinosucate/la T A:<-.!l"RA, On the other hand, the latter has the new subgenus. same external ornaments as G. (C.) lati clava HEALEY. The internal ridge and Type-species :-Catella (Torinosucatel/a) the external constriction of Cate/la are kobayashii T.·\:\tt:RA, new species. evidently different from the ventral Diagnosis :-·Catetla with radial ribs sinus of Paml!elodon or Barbatia in and concentric wrinkles on surface; which the sinus forms a byssal gape. posterior end protruded and generally Emphasizing primarily the internal auriculate; hinge of Grammatodon type. I B c D E J[ . 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). produced: median constnctwn deep. broadened and becomes shallow near Cate!la ( Torinosucatellal kobayashii venter; anterior area smaller than pos TA:-.tt.:RA, new species terior: constriction a little strengthened Plate ti. Figures 11-16. internally; ventral margin fairly deep ly sulcated at the median part: carina Description :-Shell small. inequi lateral. like ridge round-topped. passing from well inflated, trapeziform in out line; umbo to postero-vcntral margin; post umbo at about 1/3 across from anterior carina! area depressed: surface orna end. slightly prosogyrate and incurved; mented with dense radial ribs and hinge line longest, straight and auricu several concentric wrinkles on \'Cntral late posteriorly; posterior margin a side; hinge of Grammatodon type. little sulcated; postero-ventral corner J\Ieasureme11tS :- 5() l.l.1i1Wl'zt TAMURII L H about twice the height: umbo nearly holotype 1:l mm Gmm orthogyrate. situated a little anteriorly; 12 6 antero-clorsal margin a little shorter 10 4 than posterior, both margins nearly Comparison:-The ventral sinus is straight and forming 140°-150° apical deep but the gape, if present, is narrow. angle at umbo: anterior extremity The posterior auricle and long hinge rounded: posterior extremity a little margin are also distinct specific charac rostrate. situated above the middle of ters. Externally. this is similar to alate the height: ventral margin evenly Para!lelodon as typified by P. rugvsum rounded: surface ornamented with fine (AREELL, 1930-1). The median sinuation numerous concentric growth-lines: no is absent in the alate group. disinct carina on rostration: hinge teeth G. (C.) sinuatus Ttwt·:ussor-; somewhat discontinuous below umbo and very resembles this in ornaments but bas minute below umbo: chonclrophore in· coarse ribs. The posterior dorsal end visible: anterior series of chevron of sinuatus is probably not so distinctly shaped teeth nearly straight. about :{0 alate as in kobayashii. Macrodon sp. in number: posterior ones a little arcuate (FtEBELKOR:x. ?vi.. 1893) in north German and 50 in number: two short irregularly boulder derived from the Upper Juras· disposed ridges running from umbo to· sic formation has a fairly deep sinus as wards anteroventral margin and attain in this species but its sinus is not so ing nearly the midheight. deep as in this species. The sandstone of Infra-Lias of Hettange, Vic-de-Chas· senay and Halberstadt yields Area jmlla TERQ. which has a distinct constriction in the middle part ancl rae! ia I and con· centric ribs on the shell. The hinge of Text-Figure 2. Internal mould uf A. pu!la, however, is not of Grammatodo11 Nucuhma (Praesacce/la) erinoensis (Kl:\tl'RA) type. showing internal ridges. Occurence :-Locs. 6. 11. 1Heasurements :- Family I\uculanidae L H hulutypc 24 mm 1-tmm Genus Nucu/ana Lt :XI<. 1807 37 19 21 13 Subgenus Praesaael/a Cox, 19cl0 ? 15 21 9 Nuculcma (Praesaccel/a) erinoensis Obserl'ltliou and Comparison :-Several Kt:-.tURA internal and external moulds of both Plate 6, Figures 3-6. valn•s from the Sakamoto formation arc larger than in the Torinosu group in 1956. Nuculana (Rollieria.,) eriuoensis. KI:-.tt·· Sakawa basin. Partly due to deforma RA. p. 84. pl. 1, figs. 3. '1. tion the shells vary in outline. Internal Description.·-Shell medium sized for ridges of this species are distinct. The genus. depressed. su beq u i lateral, elonga posterior gaping is seen in a specimen tely ovate in outline, with the length (Fig. 3). Rol/ieria has ovate in shape in 359. Taxodonta and Isodonta from the Upper Jurassic 57 general, while this form is elongate and Nuculana (Praesac.) erinoeusis I\1 \WRA rostrate posteriorly. Therefore it is which occur together. The smaller size, better located in Praesacce!la than in more inflated form, smalier number of Rol!ieria. chevron-shaped teeth and no irregular Palaeoneilo belae nsis Cox (1940, pI. 1, ridges on internal surface in this species fig. 1) from the Patcham bed in Cutch are its distinction from erinoensis. is allied to a specimen (Fig. 5) of the Occurrellce :-Locs. 1. 4. ll. 12. species but the posterior and anterior series of denticles are continuous below Subgenus Dan~romya AGASSIZ. 18•!0 the umbo. Occurrence :-Locs. L 4. :1. 6, ~l. 11. 1:2. Nuculaua ! Dacryomya) stenodolic/zos Kl\fi:RA Nuculmza \Praesarcella) yatsushiroensis Plate 6. Figures 17-19. T.\:o.n·R,\, r~e\v species 1956. Nuculana (Dacryomya) stenodolicllos. Plate 6. Figures 7. 8. 1<1\ll'I Shell very small for genus (L : 6 mm. all surface. H: 9 mm). Right valve subequilateral, Comparison:-This species closely re strongly depressed, elongately ovate; sembles Chlamys (Radulopecten) in hinge margin straight; postern- and equicostatus (PIIILLIPs) from Osmington antero-dorsal margins nearly straight Oolite from Yorks but the presence of and steeply sloping and forming about distinct radial riblets on chief ribs of 70° angle; ventral margin rounded but the right valve distinguishes this from a little oblique to backward: ears that species. Japanese Gloripallium from moderate in size: anterior a little larger the i\Iiocene (G. izurensis 1\lAsuoA, 1958 than the posterior. anterior and posterior etc), is very alike this species. There extremities acute- and obtuse-angled re fore Jurassic Radu!opec/en may be an spectively; sulcation below anterior ear cestral to Gloripa/lium. indistinct ; surface scu lpturecl by 8 or Occurrence :-Loc. 11. lU radial ribs which are narrower than their interspaces and crossed by fine Cll!amys (Radu!opecten) ogmceusis concentric striae. (Kn!FRA) The right valve of Cll/amys (C/i.) iboibo is similar to this specimen, but the small Plate 6. Figure ai. number of radial ribs distinguishes this 1951. Aequipecten ogawensis, KIMURA, p. 3·13, from that species. pl. 1. fig. i. Occurrence-Lac. 6. 1\1:-.1t;RA compared this species to Ch!amys (Aequipecteu) fibrosa (Sow.) by Subgenus RadulojJec/en RoLLIEI{, 1911 AIIKELL (1931). A group containing Clzlamys (Radu!opecten) 11agatallensis fibrosa is now included in Radulopecten (Cox, 1952). KuRATA and KIML-RA Occurrence:-Two internal moulds of Plate 6, Figures 31, 32. both valves from Loc. 6. 1951. Chlam_,·s nagatakensis, K1:-.1URA, p. 338. pl. ], fig. 1. Genus Aequipecten F1scHER Description :-Left valve depressed. ".:lequipecten ·· llu!garis KIMURA slightly inequilateral, orbicular, longer than high; hinge margin about l/2.5 of Plate 6. Figures 40, 41. the length, straight: cars unequal, an 1951. tlequipccten l'lllgaris. Kl~lt.:RA. p. 342. terior one about twice or more than pl. 1, figs. 5, 6. posterior; two diverging radial riblets Radial ribs are about 13 in the Saka on anterior ear: extremity of anterior moto form and their interspaces sculp ear nearly 90° and posterior one obtuse tured by about 4 fine riblets. angled; sulcation below anterior ear Occurrence :-Several specimens from indistinct ; dorsal margins nearly Locs. 3. 4. 11. straight, forming about 100° apical angle: ventral semi-circular; surface "Aequipeclen ·• kotsubu (K1 ML'RA) sculptured by 8 radial ribs among which middle ones are wider than laterals; Plate 6, Figures 33, 34. their interspaces nearly as wide as ribs: 1951. Neil/tea kotsubu. KI:-.IURA, p. 343, pl. 1. very fine radial and concentric ribs on figs. 8. 9. 359. Taxodonta and Isodonta from the Upper jurassic 59 Description :-Left valve small, fairly ous umbo and coarse radiating threads. convex. inequilateral. a little longer than The sole difference is the lateral gap high: hinge margin straight; anterior ing of the ear of this specimen. ear larger than posterior one; anterior Oaurreuce .--Loc. 6. extremity acute-angled and posterior one obtuse-angled: byssal sinus below an Camptonectes ? sp. terior ear indistinct; two radial riblets on anterior ear divergent from umbo: Plate 6, Figure 39. anterior dorsal margin straight, longer An external mould of a left valve than a little acute posterior one: beak slightly broken in hinge part, very small a little projected beyond hinge margin: for genus, orbicular in outline, nearly apical angle about 90°: ventral margin flat: posterior and anterior lateral rounded and a little produced anteriorly: margins nearly straight, rounded. a surface covered by fiat-topped about 22 little obliquely elongated backward: radial ribs, their interspaces wider than hinge not clear. dorsal margin straight; ribs. beak not reaching dorsal margin: sur Comparison:-The Sakamoto specimens face covered by 9 erect concentric are more inequilateral than Sakcnva form laminae at regular intervals which are but it is evident that these specimens obsolete near umbo. are allied to lwtsubu. These specimens The regular concentric laminae of the from the Sakamoto area are included in specimen somewhat resemble the orna " Aequipecten ·· because of biconvexity ment conspicuous of Camptonectes annula of the valves. tus group but radial threads on surface Occurrence :-Locs. 3, 4, 11. are invisible in this specimen. This sole specimen is verv small (4 mm high. 3 Genus Camptonectes MEEK, 1864 mm long) and its specific characters are imperfectly known_ Camptonectes sp. aff. brozcni Cox Occurrence :-Loc. 8. Plate 6, Figure 42. Genus Fopecfen DotcYILLf, 1897 aff. 1935. Camptonectes browni, Cox, p. 171. pl. 18. figs. 13a, b. Eopecten sp_ new Left valYe (34 mm high and 30 mm Plate 6, Figure 49. long) subequilateral, fairly inflated. nearly orbicular: umbo prosogyrate, a Left valve small (H: 13mm. L: 14mm). little projected beyond short hinge inequilateral, orbicular, moderately con margin: ears neither large nor promi vex and elevated near umbo: dorsal nent: anterior ear inflated and gaping margins nearly straight. a little longer laterally, not delimited from the shell in anterior than the other: ventral a body: surface covered by radiating little produced anteriorly and orbicular: threads. coarser than the Camptonectes primary riblets fine, 20 or more: second ornament, and by obsolete concentric ary finer threads intercalated. ribs at irregular intervals. Ears are not clearly defined from the The specimen closely resembles shell body. Surface ornament is charac Camptonertes browni Cox (1935) from the teristic of Eopecten. Ve!opecten rollei Callovian of Somaliland in its prosogyr- STOLL. (PcELr:-.cE\·, 1937) from Pliensba- 60 Afinoru TAMURil chian of South Ossetia of L S. S. R. the Sakamoto area shows distinct radial resembles this specimen but concentric ribs. A byssal gape below the anterior plication is weaker or less in the latter. ear is fairly deep. Therefore it is evi Occurrence :-Only an internal mould dent that this species belongs to Vari of a left valve from Loc. 11. amussium SAcco instead of Propeamus sium GREGORIO (PHILIPPI, 1900). Family Amusiidae 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'!:\. Plate 6. Figure 30. p. 344. pl. 1. figs. 14. 15. 1951. Entolium yatsujiense. Kl~ll'RA. p. 3·15. Description :-Shell small. subequi la pl. 1. figs. 18a. b. teral, depressed. slightly higher than This is involved probably in the long. Right valve depressed but more group of Entolium cingulatum GoLDF. convex than !eft; hinge margin fairly (ST.uscHE, 1926) by the presence of a long. straight; anterior one twice or pair of distinct internal ridges close to more than posterior: anterior and pos the auricular margins. The shell of the terior lateral margins a little concave. Sakamoto form is variable in size (4mm forming about 100° apical angle: ven to 10 nun in height). tral semi-circular: ears fairly large. Ocwrrence: -Lacs. 6. I, 9. 11, 1~. all depressed and distinctly marked from in the western half of the area. body: anterior ear large; byssal sinus below anterior ear fairly deep: surface sculptured by numerous fine regular Entolium l?imurai T,\;..ll'RA. new species concentric lines: about 9 elevated ribs Plate 6. Figures 23-29. on internal surface a few of which arc restricted to ventral side: these internal Description :-Shell medium to small ribs do not attain to yentral margin. for genus. cquivalve exclusive of hinge Left valve similar to right valve but area. equilateral. depressed, elongately has about 20 or more radial ribs. In ovate to orbicular in outline and higher each interspace 1 or 2 finer ribs are in than long in general: dorsal margin serted and intersected by numerous short and straight in left ,-alve but regular concentric lines: these radial ribs rises above hinge margin in right valve; impressed feebly on internal surface. ears small, equal and their extremities Comparison:-This species was group roundedly obtuse-angled and depressed: ed in Propeamussium by KI~IPI~,\. as the auricular margins short. slightly arcuate radial ribs on the left valve arc not of or nearly straight and forming nearly Vm·iamussittm. But the internal feeble 90° apical angle: ventral margin ovate: riblets (KI~n:RA, 1951. pl. 1, fig. 15) sug surface smooth: internally, auricular gest the presence of radial ornaments crura short but distinct: internal ridges on the surface of the left valve. An obscure near auricular margins; wing imperfect external mould (Fig. 21) from like elevation near umbo present in 359. Taxodonta and Isodonta from the Upper Jurassic Gl each ear. corners rounded and obtuse-angled: Jfeasurments: -· dorsal margins in right valve rise above L H Apical angle the straight hinge margin: surface holotrpe 14 mm 18mm 90" smooth; internally auricular crura pre 18 19 100 sent; a paired triangular wing-like 12 14 100 elevation below hinge margin: strong 14 13 110 angular conical tooth found between 11 lG 90 paired pteriform elevations in right 9 12 80 valYe and a corresponding socket in left Obsen•ation :-\hny specimens in hand valve; lower surface of the tooth gro are deformed in some degrees but their oved. morphological variance can not be de nied. 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 from the typical form. l\leasurements and Figs. 23-29 sho\\' morphological variance of this species. Comjmrison :-This species somewhat resembles E. japonicum Kn~. and K1~1. Tcxt-Figurl' 3. Somapccten lwmimaucnsis from the Sakawa basin. The latter. KI:-.JL'RA: exterior of left vah·e (a) interior however. has a smaller apical ani-!lC of left vahl' (b). interior of right valve (c). (about 70°). its anterior car is larger Remarks:-Jurassic l~'ntolium and Late than the posterior and the dorsal margin Palaeozoic Pemopecteu ~:\EwEu.. 1937) of japonicum docs not rise above 1he arc the group having smooth surface hinge margin. En folium demissum P 1111. 1.. and no ribs internally in the Amusiidae. (STAESUIE, 1926; AI~I,EJ.L, 1929) and E. though the two diverging distinct in disc~rormis ScHL'EB. (DEcJL\SEALx. 1936) ternal ridges near auricular margins are are closely allied to some forms of this present in I he group of Entu/ium species (Figs. 211- 28). But fine growth cinf.!u/atum (Go~.nr.) and the latter may lines are destitute in this species and be ancestral to the former. Somapecten the shell is much smaller and generally is very akin to Entolium by its orbicu not so circular as in these species. lar. compressed. subequivalved equilat Occurrence:- i.\1lost abundant and wide· eral shell and smooth surface. except for ly distributed in Sakamoto area. Locs. the peculiar tooth and socket. Dorsal 2. 4. 5. 6. I. 9. 11. 12. margins of the right valve in Entolium and Somapecten rise above the hinge Genus Somaj}(!l.·lcn KI:-.II'IL\. El;)l margin, though it can be seen in the Type-species: Somapeclen lwmimancnsis left of PenzojJec/en (anterior and poster KntL'RA. ior direction are based on weak adduc Diagnosis :-Shell equivalve exclusive tor scar in Somapecten). Two divergent of hinge area. equilateral. depressed but auricular crura and paired wing-like biconvex, elongately ovate and fan elevations helO\v the hinge margin are shaped, higher than long; ears equal also common characters between both and fairly large for the family, their genera. Whether it belongs to the Amusiidae or not is a problem because lateral margins are unkno\Yn. A long but its cardinal tooth in right valve and its narrow axial elevation from umbo to socket in left have never been described midheight probably corresponds to the in the Amusiidae. Kn,HJRA compared tooth and its extension. this genus to Ento/ium and referred it to the Pectinidae. Here the writer Family Limidae places it in the Amusiidae owing to its Genus Lima BRt.:GVIERE. 1797 resemblance to Entofium except for the tooth and socket. Subgenus Plagiostoma SowERIIY, 181,1 Lima (Plagiosfoma) sp. Somapecten kamimanensis 1\.1 ~n; RA Plate 6, Figure '18. Plate 6. Figures 50-55. A broken external mould of a left 1951. Somapeclen kamimanensis. KIML'IL\. p. valve which lacks hinge area is refer 347. pl. 1. figs. 19. 20. red to Lima (Pfagiostoma). It is very Descriptioll :-Shell medium. equivalve inequilatcral, a little convex. trigonally exclusive of hinge area. depressed and ovate, length much greater than height biconvex, elongate!y ovate or orbicular (L: Hi mm. H: 11 mm); antero-dorsal in outline: ears equal. depressed, demar margin straight and three times as large cated from shell body, fairly large: as posterior, forming ll0° apical angle; auricular margin with shell body long: ventral margin rounded and antero-vent dorsal margin in right valve rises above ral margin projected: surface covered hinge margin but straight in left valve: by about SO radial ribs which are wider extremities of ears roundedly obtuse than their punctate interspaces. The angled in both valves: dorsal margins obliquity of shell, many fine radial ribs (or auricular margins) straight, fairly and punctate interspaces of the speci long and forming 80-90° apical angle: men are all characteristic of Plagiosloma. ventral margin orbicular and fan-shaped: although the hinge area is invisible. surface smooth: test thin. having very Occurrence :-Loc. 11. minute radial and concentric structure: internally, auricular crura short and Subgenus Ctenoides l\16rch. 1853 improminent; paired triangular wing like elevations below hinge margins: Lima (Ctenoides) tosana Kn~ATA angular conical cardinal tooth, grooved and K1~1t.:R.\ at base. projected in right valve. and Plate 6, Figures 44-47. corresponding triangular socket in left valve; resilifer not demarcated from the 1951. Lima (Cienoides) tosana. Kll\IL'RA, p. tooth or socket. 349. pl. 1, figs. :!2a. b. ObserL>ation :-Several specimens at Occurrence :-Common at Locs. 4.~6, 11, hand vary in size. some of which being 12. deformed. As Kl~IURA stated, there are two kinds of shell outline in this species Genus Lima/it/a W ooo, 18:19 of the Sakamoto area. i.e. quite orbicu Limatufa reticulata T_..,_\IURA, lar form and ovate form, much higher than long. Most Sakamoto specimens new species belong to the latter. Gapes on anterior Plate 6, Figure 43. 359. Taxodonta and lsodonta from the [Jpper jurassic 63 Description :-Shell inequilateral. inflat 1930) differs from L. reticulata, in the ed. elongated. and height much greater striae of i nterspaces. than length: hinge margin short and Occurrence :-Loc. 11. straight: antero-dorsal margin slightly arcuate or nearly straight : postero dorsal a little rounded: ventral rounded References cited and produced: beak distinct but not pointed. a little projected beyond hinge ARK ELL. W.]. (1930). The Generic Posi· margin: ears small. anterior one larger tion and Phylogeny of Some Jura8sic Aridac. Ceo!. Mag., Vol. 67. than posterior one. not delimited from DECH.\SE\t:x. C. (1936), Pectinides Jurassi· shell body. extremity of anterior ear ques de l'Est du Basin du Paris .. Ann. obtuse-angled and posterior one nearly Paleont.. t. 25. 90°: surface covered by about 18 regular FIEflELKOR!'\. M. (1893). Die norddeutschen ridged radial ribs which arc restricted Geschiebe der Oberen Juraformation. to main part of shell body: its lateral 7eits. Deutsch. Geof. Ges., Bd., 45. Berlin. sides smooth: posterior side of rib a HEALEY. M. (1908), The Fauna of the Nap little narrower than anterior one and eng Beds or the Rhaetic Beds of Upper both sides striated by numerous fine re Burm:-t. Palaeoill. Indica, N. S .. Vol. 2. ticulate ribs. inserted by low secondary 1llem. No. ·1. KtTTL. E. (1903). Geologie der Umgebung ridged radial ribs. von Sarajcbo. ]allrb. k. ll. geo/. Reichsanst., TYien, Vol. 53. --~>A lVIASlT>A. K. (1958), On the Miocene Pectini· u 1 2 dae from the Environs of Sendai, Pt. 11. Trans. Proc. Palaeont. Soc. japan. N. S., ~ I\io. 31. R r NEWEL!.. N.D. (1937), Late Paleozoic Pelecy· r pods : Pectinacea. Kansas Geol. Sun• .. Vol. 10. I II PcF:I.Jl'\CEV. V. (1937). The Gastropoda and Text-Figure .1. Radial rib of Limatula Pelecypoda from the Liassic and lower reliculata TAllfl"RA: Dogger of the Tetis in the limits of the I : side view. II : profile of rib. 1-2: USSR (the Crimea and Caucasus). cutting place. A: anterior, U: upward. Paleont. USSR Monogr., Vol. 48. R: primary rib. r: secondary rib. P!ltLIPP!. E. (1900). Beitriige zur Morphologic und Phylogenie der Lamellibranchien: Comparison:-The external and inter Zeits. Deutsch. geol. Gesel!s.. Vol. 52. nal moulds of a right valve (L: 10 mm: STAEscrm. K. (1926). Die Pectiniden der H: 2lmm; apical angle: 50°) are present. schwabischen Jura. Geol. Pafaeont. Abh., The tall shell form and surface orna N. F, Rd. 15. ment as seen in Fig. 4 are characteristic TA~IVRA. M. (1959). Trigoniidae, Ostreidae. of this species. It resembles Limatula Bakevelliidae, Pteriidae, Cardiidae and Astartidae from the Upper Jurassic gibbosa by SO\\·. i.MoR. & LYe .. 1853) but Sakamoto formation in Central Kyushu, it is much obliquely expanded and the Japan. Trans. Proc. Pal aeon/. Soc. ] apan. secondary ribs are inserted bet ween N. S., "Vo. 33. primaries. Limatula coral! ina ARKEL L TERQUEM. 0. (1855). Paleontologie de l'etage (ARKELL, 1929! has no secondary ribs infcricur de Ia formation liasique de Ia and L elliptica ('WiiJTEA\'Es) (i\Rf(ELL. Province de Luxembourg. Grand-Duche 64 lvlinoru TAMURA (Hollande), ct de Hettange. du Ia Mosel· See also ARKELL (1929-31). Cox (1935, 19-10, !e. !llim. Soc. gl;ol. France. Si:r. 2. Tom. 5. 1952), KIML'I~A (1951, 1956), MoRRIS and TRoEosso:-<, G. (1951). On the Hoganas LYCETT (1853) in Bibliography of Trans. Series of Sweden. l\.tmg!. Fysiogr. Still. Proc. Palaeont. Soc. japan. N. S .. No. 33 Hand/., N. F. Bd. 62. Nr. 1. of this study. Explanation of Plate G (All figures show side view unless denoted) Grammatodon lakiensis K1 ~~ L RA Fig. I. Internal mould of a right valve: Loc. !J. x2. (1•11•1 3013). Fig. 2. 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. (?liM 3020). 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 : Upper Jurassic Taxodonta and Isodonta Plate 6 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\1 3067). 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\lM 3071. 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 AGI PREFECTURE. WITH SOl\IE STRATIGRAPHICAL RK\IARKS* (Studies on the Liassic Pelecypods in Japan. Hl) ITARU HAYAlVII Geological Institute, Uni\-ersity of Tokyo 7l In ~Iizunuma area of Inai village, port the brief outline of the stratigraphy l\liyagi Prefecture, Jurassic deposits and describe some new pelecypods. show a horseshoeshaped distribution. Interesting are the occurrences of Cam This area occupies the southern part of ptonectes (s. s.) and Burmesia in the low the western synclinal belt of the Kita er Liassic beds. Although fossils of kami Jurassic (KonA YASHI. 1948) and is this area are strongly deformed by located at the northeast of the well crustal movements, most of them are known locality of Anisic ammonites at specifically determinable by close com Inai. Since hAI and T\KAilASHl (1940) parison with the better preserved Nira had commenced the stratigraphy of this nohama fauna already described hy Yo- area. the Jurassic sediments were in 1\0YA~IA (1904). KoBAYASHI and !\IoRI vestigated by YosJIIDA (19 111. l\fS) and (1954) and myself (1957a, b, l958a, b, c, I-1."-=-DA (1953. MS) whose works were d). birefly cited respectively by KoBAYASHI Here I express my most sincere thanks (1948) and 0=-uKl (l!l56). Their results to Prof. Teiichi KonAYASIII of the Univ agree with one another in the major ersity of Tokyo for his kind advices and classification and distribution of strata, supervision of this manuscript. although the nomenclature is confusing to a certain extent. Stratigraphical Notes Lately I surveyed this area and col lected fossils. As the result it was In the l\Iizunuma district the sedi found that the stratigraphical division ments from Upper (?) Triassic to 1\Ialm and chronology of this Jurassic require form a syncline. "Se:ymourites" at Ishi some emendations. In this paper I re- zaki is a solitary ammonite, but by ------litho!ogical resemblance the Jurassic * Received Aug. 22. 1958; read Sept. 27. 1958. sequence of Mizunuma can be correlated G6 360. Pelecypods of the ivlizunuma jurassic 67 Table 1. Division and Correlation of Mizunuma Jurassic 1\·Iizunuma Area , Shizukawa Area [ Standard I ______I MAnL;TI (H133) 1:--:AI and TAI\AIIASHI (1940) I I·LWAMI (1959) i em. 11'AI (1939~~ _ --~---- H h' 1 Sodenohama fmt. Maim Arato fmt. as I·' Samurai- I Owada sh. 1 ura , Arata fmt. hama gp. 1 I Aratozaki fmt. gp. A t k' f t Dogger ______I I ______ra oza I m _· --l-- Mano gp. lMizunuma sdy. sh.[- -hiatus- : Shizu- I llosoura fmt. 1 (Aalenian) --· J\lizunuma fnlt. kawa I f I L' gp Niranohama mt. 1 tas Shizukawa Mizunuma sh. Xir<1110hama fmt.1 · gp, ?l'iizunuma ss. Saragai fmt. S~mt. -~ Xoric --- Inai group lnai group lnai group Anisic Sky tic ----I with that of the Shizukawa district, as new species shown in Table 1. Geratrigonia ltosourensis (YoKOYAMA)* In this area there are more than 300 Homiodon lrmulatus (YoKOYA'-'IA)* meters' more or less arkosic sandstones Eomiodon vulgaris HAY:\~~ I* below the Niranohama formation which E'omiodon (?) giganteus HAYA:\11* contains the typical Niranohama fauna }'okoyamaina elliptica (YOKOYA!\1.'\)* Tltracia subrlwmbica HAY A!I 6m. Black bituminous shate with fo.fodi also in that fauna. But the :'\apeng olus. Thracia and Cuspidaria (?). fauna is characterized by Bakeve/lia 11m. Black fine sandstone with Para!lelo· praecursor and "Pteria" contorta. which don.JI!odiolus, Baket·ellia, Gerrillia. !so are considered important Rhactic indices, gnomon. Camptonectes. Geratrigonia, while the present fauna lacks any Tri· Eomiodon tzmulalus, H. mtfgaris. Yo· koyamaina, Prolocarclia. assic clements. The occurrences of 30m. Black bituminous sandstone and shale Bunnesia have been restricted to the (barren of fossils). Upper Triassic of Southeastern Asia 12m. Black bituminous shale with Bake· (Burma, Indochina and Molucca) and z:e/lia, Eomiodmz vulgaris. Cuspidaria Jordan Valley (?), but Hrmnesia japmzica. (?) and Burnll'sia. n. sp. is probably a lower Liassic 35m. Black tine sandstone (barren of fos species. because in Shizukawa and this sils but for plant fragments). areas it is found in one bed altogether 2m. Basal conglomerate containing nu· with Eomiodmt and other pelecypods merous pebbles (';'em. in max. dia which are quite different from Upper meter) of underlying rocks. Triassic faunas hitherto known in Japan. -- disconformity -- The resemblance between the Napeng Dark grer sandstone of the Saragai (?) formation. and the present fauna may be primarily due to simi far sedimentary environments. This locality has hitherto been included This presumption is endorsed by the in the .. :\Iano group". b:AI and TAKA· Shinatani fauna in the Kuruma group IIASIII (19,10) listed ilrcomya sp. (aff. A. which is dated as Domerio-Toarcian but cornuta ~vi.), Pleuromya sp. (cf. P. recurw contains also somewhat simi Jar genera (;oLDFJTss). Jl1rzcrodmt cf. hirsonensis to the Napeng and Niranohama beds o'ARciiiAc and Gen•illia sp. (cf. Gen•z'flia (KooAYAsiii et al.. 1957). I made some ferruginea B~-:~Eci-:r-:) from this horizon other stratigraphical and tectonic obser and suggested Dogger for the group. vations in this area, but the rcsulls will Many other fossil localities are zonall~~ be reported on another occasion. traceable in this area from Futamataji to the northern slope of Kusakariyama llescription of Species (315.0 meter's peak) where I (195/bl re ported Gen•illia (Cultriopsis) shizuluauensis Fam i Iy Para llelodon tidae D A 1. 1. and Gerl'illia sp. These localities are Genus Parallelodon 1\iEEK and considered almost of the same horizon. \VowmE:-;, 1866 Anyhow. the pelecypod fauna at Futa mataji is lower Liassic instead of Dog ( = l\facrodo11 BucK ~IA;o;, 18-H. ger. and the '' :rvlano group " is at least 11011 Mi'LI.ER, 1842) in part synchronous with the Shizukawa Para/le/odon uiranohamensis HA YAM I group. Plate 7. Figures 1, 2. It is interesting that this fauna is fairly similar in the generic assemblage 1958. Para!lelodmz 11iranolwmensis HA YAJ\I I. Japau. four. Ceo/. Geogr .. Vol. 29, Nos. to the Rhaetic (or Noric) :\lapeng fauna 1-3. p. 100. pl. 7, figs. 1-4. of Upper Burma and its equivalent in Indochina. Parallelodon. Bakez,ellia, Ger· An internal mould (Fig. 1) shows near l'illia, l sognomou. Thracia, Cuspidaria I?) ly vertical granular median denticles and Burmesia are important constituents and weakly crenulatcd subhorizontal 360. Pelecypods of the Mizunuma jurassic 69 elongated posterior teeth. An external the difference in inclination of median mould reveals numerous fine radial clenticles generally does not serve for threads and irregular concentric growth distinction of subgeneric or higher lamellae. The holotype from Shizukawa category in para1lelodontids. area has a more similar dentition to Ocrurence:-Rare at Futamataji. north Para/le!odon rugosus rBL·cK:o.tA:-;) in !\.R east of i\'lizunuma. KELL (1930) than .·lrca keyserlingii D'OR Brc:-;Y in Arn;ELL. as noted before. Then Family Bakevelliidae Kr:-;c I considered that the inclination of median denticles is important and that Genus Balm,e!lia Krxc;, 1848 Cosmetodon BR,\:-;sn:--: (19·1~) ( =Beushau Bakez•ellia cf. trigona (YoKOYA:O.tA) senia in AHKELL's sense) is subgeneri cally distinl-{uishable from Parcrllr>lodon Plait: 7. Figure 3. (s. s.) by the divergent median denticles cf. 190-l, Gerl'illia trigona YoKoYA~lA. jour. from the base of hinge-plate as in Gram Col! Sci. Imp. Unit•. Tokyo. Vol. 18. ma/odon. even if the undeveloped pos Art. 6. p. 12. pl. 2, t1gs. 7 and 8 (?). terior wing. which was regarded as the d. 1957. BaluJre/lia trigona. HA YA)\1!, japa11. subgeneric character of Heuslzausenirt by ]our. Gcol. Geogr .. Vol. 28. Nos. 1-3. ARKELL (1930). is not a diagnostic cri p. 51. pI. 2. figs. 1-5. terion. According to Cox's personal Represented by an internal mould of communication* received on 2Gth. f\Iay, left valve fMiVI 292G. 88.5 mm. long: 1958. however. no generic or subgeneric 51.0 mm. high: 11.5-7-mm. thick). Shell distinction can be based on the hinge large for genus, reverse trigonal, mode teeth. which are very similar between rately inflated. much longer than high: P. rugosus and Area keyserlingii D'OR hinge-line as long as shell: posterior BrcNY. type species of Cosmelodon BRM.: wing small. flattened. defined by slightly SON (1942).** In the inclination of median sigmoidal postero-vent raJ margin: hinge denticles these Mizunuma specimens plate narrow. provided with one or two are somewhat different from the halo oblique terminal cardinal teeth and a type and fairly similar to Parallelodon curved weak posterior lateral: ligament buckmani RrciiARnso:--; in ARKELL (1930) area moderate in breadth, faintly stria from the lower Lias of England. But it ted subhorizontal lamellae. provided with is only due to intraspecific variation. for 7 or more slightly opisthocline quadrate their outline and surface ornaments an~ ligament pits arranged almost equidis the same to the Niranohama specimens. tantly. It is concluded that the dentition of This specimen is ur:doubtedly com this species is fairly variable and that pressed secondarily in dorso-ventral direction. In the large size and terminal * I am greatly ind<.:bted to Dr. Leslie H. cardinals. this resembles BaketJe/lia mag Cox of British :Yiuseum (Natural History) nissima 1-l." YAW (195/a) from the Dom who kindly gave me reply to my questions erio-Toarcian of Central japan. but on Parallelodon and some other pelecypod gen coincides with lrigona in other charac era. ters. Judging from its age, this may ** In my opinion Cosmetodon BRA:'>SO:'\. if the subgenus is valid, is not acceptable as be a transitional form from trigona to a substitute of Beuslumsenia Coss~·!A1\'X (1897). magni ss ima. because of the different type species. Occurrence:- -:\:izunuma formation at 70 Itaru ll4 Y.4MI the north of \Iizunuma, more or less cavated to form abyssal notch; ctenolia younger than the Hettangian i\irano distinct. five or more in number; left hama formation. anterior auricle very large, subtrigonal with a slightly convex anterior margin, Family Pectinidae Lu.L\RCK truncated subvertically at corner, ill defined from main body: posterior auricle Genus Camptonectes 1\'Tn:E, 186:1 of each valve comparatively small, tri gonal. truncated obliquely. well defined; Camptonectes (s. s.) inexpectatus surface of main body and auricles but JL,Lnll. new species for byssal one ornamented with num Plate 7. Figures 4, 5. erous fine flabellate characteristic Cam ptmzectes-st riations "·hich are never Description:-Shell medium to small punctate, often bifurcated near ventral for genus, inequivalve. fairly inequila periphery of left valve and strongly teral, nearly acline. not strongly inflat bent up in both lateral areas: umbonal ed; antero-dorsal margin of main body region almost smooth; concentric lamel slightly sinuated in each valve. while lae somewhat regularly spaced but re postero-dorsal one is nearly straight: stricted to anterior part of each valve: umbo lying near mid-point of shell on lett anterior auricle more than ten length but at about two-thirds of hinge erect subvertical lamellae countable al line from front, very slightly prosogy ready from early stage and abruptly rous: apical angle probably about 115 strengthened in middle stage: in later degrees, though the value is with no stage some of them con! i nuous to an accuracy because of deformed material. terior part of main body and fading and may be more or less smaller in early away downwards from inner side: bys stage: auricles of two valves very un sal auricle marked with numerous con equal in size and shape: right anterior centric lamellae of growth. while they one, i.e. byssal auricle. protruded for are very weak on posterior one of each wards, of C!tlamys-type. about twice as valve: resilifer triangular, completely long as posterior one. defined from main internal: hinge and crural teeth absent: body by an auricular sulcus, deeply ex- musculature unknown. J1!easurement in mm. Length Height Thickness ~---~ ~--- -~~------Holotype (!\1M 2927) left ex. mould 12. 5+ Hl.5+ 2.5 Paratypc (MM 2928) right in. mould 27.5 25.0 ·1. 0 Observation a11d Comparison :-Four tinct ctenolia. though more or less com specimens are more or less broken or pressed in dorso-ventral direction. The deformed. The holotype (Figs. -la-c) mode of surface-markings may be some shows nearly complete antero-dorsal part what different between two valves. In of left valve. ill-defined anterior large right valve CamPI01zectes·striations are auricle, typical Camptouectes-striations comparatively weak and increase their and prominent concentric lamellae. The number by insertion. but mainly by paratype (Fig. 5) reveals almost complete bifurcation in left valve. rmtline of right valve, resilifer and dis- Several species with Camptonectes· 360. Pelecypods of the ivlizzmunza Jurassic 71 striations appeared already in the Per and C. aratus from Europe, India. and mian of ~orth America (~EwELL. 1931) South America in having non-punctate and again in the Upper Triassic of Japan surface. more prominent concentric (:\AIC\ZAWA, 1952). but this genus lamellae on large left anterior auricle flourished most extensively in Aalenian and anterior part of main body. In these and later times. So far as I am aware. respects this may be more related to there are few representati\·es of true Camptonectes laminatus So\\·ERBY •1821) Camptonedes in the Lias (exclusive of from the Dogger of England. New Zea I\alenian) except for Camptonectes psil land and Argentina. According to AR onoti STAESCIII' 11926) and Camptonecles KELL (1930b), C. laminatus is distin sp. in DECHr\SEALX fl936. p. 29, pl. 4, figs. guishable from lens by the large left 1-8). STAESCIIE and DEcHASEAtx con anterior auricle which bears some ten sidered that Pecten tmnctassimus QL: I·:N conspicuous raised verticle lamellae (12 s-rwT (185(): Tr:IHllJDI and PIETTE, 1868) to 20 in full-grown specimens). This from the Hettangian of Lorraine and species is. however, separable from lami- some other areas is intermediate be 11atus by the absence of strong concen t ween C!tlamys and Camptonectes. but trics on posterior auricle of each valve • Cox (1952) did not accept STAESCIII,·s and longer hinge line. Judging from phylogenetical concept from finely ribbed Sowi·:Jwy's and i\RI Occurrence :-Rare at Futamataji. This of costation should be at all attributed is the first pectinid from so-called to variation within one species. I\1ost "cyrcnoid beds'' of the Shizukawa adult specimens belonging to my collec faunal province. tion show more or less V-shapcd costae on the disk, and such a tendency can be Family 'frigoniidae LAMARCK seen to some extent also in the holotype and some other Niranohama specimens. Genus Geratrigonia 1\onAY:\SIII. Geratrif!ollia is an aberrant genus, and in KoBAYASHI and 1\foRr. 195-l its distribution is sti II restricted to the Lias of Japan. Kon,\YASHI referred it Gemtrigonia !tosourensis (YoKoY.\~It\) provisionally of the Trigoniinae (=Cos Plate 7. Figure~ 6-8. tatae). though the marginal carina is very weak and the area very smooth for 1904, Trigonia lwsourensis Y OI\OYA:\IA, four. Col!.. Sci. Imp. Uniz•. Tokyo, Vol. 18, Art. the subfamily. l\ciost species of Jurassic 6. p. 11. pl. 1. fig. 3. trigoniicls in Japan occur in more or 1954. Geratrigonia hosourensis KoBAYASIII, in less calcareous coarse sandstones which KonAYASIII and !:!.loRI./apan.four. Ceo/. were formed presumably in certain lit Geogr .. Vol. 25. 1\"os. 3 4. p. 171. pl. 15. toral conditions and contain often cross figs. 1-2. laminations indicating the agitation of 1954. Geratrigonia hosourensis \·ar. com•exa Ko· sea-water. But Geratrigonia alone occurs HAYASHI in KOBAYASIII and l\foul,[bid., chiefly in bituminous shales and fine Vol. 25. Nos. 3-4. p. 112. pl. 16. figs. sandstones together with Modiolus. Bake 9a-b. N~Ilia,lsoguomon. Eomiodon. Yolwyamaina. 1\Iany specimens are identical with Tliracia and Cuspidaria (?) which are the holotype. Although all are more or hitherto called .. cyrenoid fauna". As less deformed, some observations on the discussed before (HAYAMI, 1958b). they ontogeny. specific variation and ecology must have been marine inhabitants in of this species are added here. stead of brackish ones. judging from In the largest specimen illustrated in the rock-facies and mode of fossil oc Fig. G, subconccntric costae on the disk currence, however. such a bituminous are somewhat effaced in the middle part. sedimentation must have undergone in rising up in lateral sides. On the pos a certain profound embayment where terior side of disk oblique costae are sea-water was fairly stagnant and the bluntly tuberculated. In another speci physical and chemical conditions are men in Fig. I, however, costae are never very different from those of normal tri effaced. more or less V-shaped and fairly goniid-sandstones. The peculiar feature irregular in antero-Yentral area. Some of this genus maY be attributed to the small specimens as in Fig. 8. which re adaptation to such an environment. present the early stage of this species. Occurrence :-Common at Futamataji show regular concentric costae and and the south of Kusakariyama. sharp marginal carinae. and are very similar to the specimen from Nirano Family Cuspidariidae FisCIIER hama which KonAYASIII distinguished Genus Cuspidaria 1'\ARno, 1840 as var. co1wexa from typical hosourensis. These specimens were found at one ( = Neaera GRAY. 1833. non horizon in this area, and the difference Rniii:-;I·:.-u·-Dr-:svmDY. 1830) 360. Pelecypods of the Mizzmuma jurassic Cuspidaria (?) praenipponica carination where ventral and siphonal margins meet with an acute angle: HAYA~ll. new species posterior carina sharp, nearly straight, Plate i. Figures 9-1:!. bordering posterior area which is very 1958. Cuspidaria (?) b sp. indet.. H.\YA~IL flattened and occupies about a sixth of Trans. Proc. Pal. Soc. fa pan, .\'. S .. So. whole surface: posterior gaping. if pre 30, p. 198. pl. :!ii. figs. 20-:!1. sent. very narrow: right valve having Description :-Shell small, slightly in a less inflated main body and more dis equivalYe. highly inequilateral, rostratcd tinct ante-carina! sulcus than left: and elongated posteriorly: test thin: seYeral conspicuous concentric wrinkles antero·dorsal margin slightly convex. present on surface in early stage but passing gradually into venter, while probably much weakened later: ventral postero-dorsal one slightly sinuated. long, and posterior areas marked only with turned abruptly into oblique siphonal faint concentric Jines of growth: hinge margin: ventral margin broadly arcuate teeth and chondrophore unknown, pro· but fairly concave in front of posterior bably undeYeloped. Jfeasurement ill mm. 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 Obserration and Comparison :-All hough ssic of Soul heastern Asia. "Cuspidaria·· most specimens are strongly deformed. ayabntsis NAJ(AZAWA (1956) from the the original outline may be best pre· Carnic of .Japan. CusPidaria sp. in HEALEY scryed in the holotype (Fig. 9\ This (1908) from the l~hactic (or Noric) of species is certainly conspecific with Burma. Cuspidaria latecaudata S.. wRJ;-o: Cuspidaria (?) b sp. from Niranohama. (1941) from the Noric (?) of Annam and The two i\iranohama specimens are pro Neaera sambasmza VocEL l1900) from the bably young shells, and quite similar to Jurassic of Borneo are certainly con many small specimens from this area in generic with this. As noted on .Kirano outline and umbonal concentrics. Cus hama specimens before. this is probably pidaria (?)asp. in H.\YA\11 (1958d, p. 197. an ally to N. sambasana, but differs from pl. 28, figs. 16-1 9) from the Domerio· it in the weaker ante-carina] sulcus and Toarcian of the Kuruma group is also not sinuated pre-umbonal margin. Cus· very similar to this. But I presume pidaria /aler:rmdala is quite similar to that the two forms arc specitically dif· this in general outline and strength of ferent. judging from the subvertical posterior cari nat ion. Its further close siphonal margin. less prominent posterior comparison with this is impossible at carina and absence of concentric ribs in present, because both species are repre that form. These two forms are, of sented by more or less strongly deform course. not typical cuspidariids. and ed specimens. their taxonomic positions cannot be Occurrence :-Common in black shales decided because of ignorance of internal at Futamataji and the south of Kusa structure. Several similar species ap kariyama. peared in the Upper Triassic and Jura- 7-l ltaru HAYAMI Family Burmesiidae HEALEY marked with about 35 narrow but ele vated radial plicae except for posterior Genus Hunnesia HEALEY, 1908 area: radials most dense in middle. be coming gradually sparse towards both Burmesia japonica HA YAi\11, ne\Y species sides, sometimes increasing their num Plate 7. Figures 13-18. ber by insertion: concentrics somewhat Iamel!ose, fairly strong and widely Description: -Shell small for genus. spaced in posterior area where radials equivalve, subequilateral, elongate-oval, are absent or much weakened: in an not strongly inflated. not carinated. more terior part intervals of radials excaYated or less gaping antero-ventrally and pos roundly. marked with numerous con teriorly: test thin: ventral margin centric lamellae: sometimes a narrow broadly arcuate but abruptly bent up smooth belt appears in central part : laterally, serrated at antero-ventral gap hinge apparently edentulous; chondro ing: umbo suborthogyrous. submesial. phore and ligament unknown. slightly rising above hinge-line: surface Jl[Msuremenl in mm. Length Height Thickness llolot ypc (MM 2936) left ex. mould 11. 5 3.5 Paratypc (Mivl 2937) right. in. mould :23.0 8.5 3. O+ Observation and Compm·ison :-Among spelling of latouchii) is probably the many deformed specimens. the holotype first. Anyhow, I do not consider here and paratype arc best preserved. show that such oblique costal ion is a diagnostic ing probably original outline and sur character of the genus. The taxonomic face-making of this species. The dis position of Burmesia has not yet been similarity among illustrated specimens settled. HEALE\' proposed the Burmesi is principally due to secondary defor idae, but WA:-;:'\ER and Ki'\IPSciiEER (1951) mation. The holotype is slightly broken referred it to the Anatinidae (=Later in antero-dorsal part. but the antero nulidae). ventral gaping is presumable from This species resembles closely B. growth-lines. latouchii in the general outline and dis Genus Burmesia was originally found tribution of radials. but the shell is ed on two species from the Rhaetic (or much smaller and more elongated hori N'oric) Napeng beds in Upper Burma. zontally than the Napeng species. B. But the two seem fairly different in the lirata in MA:-.:SL'Y (1921) and P,\TTE (1922) mode of costation: more precisely. Bur· from the Noric of Indochina shows simi mesia lira/a has several oblique costae lar outline, but the radial plicae of this on the anterior area which remind at species are more densely spaced on the a glance one of those of Goniomya. while middle shell-surface. Burmesia praecur· in Burmesia /aioucllii the anterior area sor KRu~wECK (1913) and B. tceberi WA:-; is marked with simple fine radials. The NER and K:-.:IPSCIIEER (1951) from the type-species of Bwmesia was not select Noric of Buru and lVIisol have oblique ed by IIEALI·:Y herself. and DIENER's ribs in anterior part and arc more simi designation ( 1923) on B. latouclzei (? mis- lar to H lirata from Napeng than to 36 0. Pelecypods of the ]VJ.izunuma jurassic 75 this species. Bunnesia? posteroradiata 16. Cox (192,1) from the Carnic of Jordan Cox. L. R. (1924). A Triassic Fauna from Valley seems not close to this. since its the Jordan Vallcv. Ann. ,1[ag. Nat. Hist .. anterior half of shell is almost smooth. Ser. 9. Vol. 14. -· (1952). The Jurassic Lamellibranch Fau lacking any radial ornament. na of Cutch (Kuchh). Palaeont. Indica, Neoburmesia iu·akiensis YAnE and S:\TO Ser. 9. Vol. 3. Pt. 4. (1942) from the Upper Jurassic of Soma Dr.cH.\SEAUX, C. (1936), Pectinides jurassi· area in Xorth Japan has somewhat simi ques de I'Est du Bassin de Paris. Atm. lar ornaments to Burmesia. But is is Pali!ont .. Tom. 25. very different from this and Napeng DtE:'\ER. C. (1923). Lamellibranchiate triadica species in the large and inliated shell, I I. Fossilium Catalogus. 1 ..!lnimalia, Pars excavated ventral margin. very anterior 19. umbo and Area-like carinated outline. Dot·\-I!.LE. H. (1907). Les Lamcllibranchet; though it cannot be a taxodont judging cavicoles. Bull. Soc. gt'ol. France. Sir. 4. from the thin test in some topotype Tom. 7. GoTTSCHE. C. (1861). Ueber jurassische Ver· specimens. Plwladomya SowEtWY !1823) steinerungen aus der argentinischen Cor has sometimes similar to Burmesia, but dillerc Palaeontogr .. Supple. 3. Lief 2, Abt. the latter is distinct from the former in 3 having a chondrophore and characteristic l-IE-\ LEY. 1vl (1908), The Fauna of the Napeng radials which are densely spaced espe Beds or the Rhaetic Beds of Upper cially in the middle part of shell and Burma. Palaeont. Indica, N. S.. Vol. 2, become gradually sparse and obscure Jlfem. No. 4. towards both sides. 11fyoplzo!as acutico 1-IAY,\~11. I. (1957a). Liassic Bakerellia in Ja stala var. nana DrKYII.LE (1907) in Lts pan. japan. four. Geol. Geogr .. Vol. 28. Nos. 1-3. SAJOL·s (1923) from the Bathonian is somewhat similar to this mode of costa -- (1957b), Liassic GenJi!lia and Jsognomon tion. but the radials are more sparse in Japan. Ibid., foe. cit -- (1957c). Liassic Chtamys. "Camptonectes" than in this species. .:nd other Pectinids from the Kururna Occurrence :--Common at Futamataji. Group in Central Japan. Trans. Proc. Pal. This species is found in some black Soc. Japan . .V. S .. No. 28. shales about 30 meters below the Gera -- (1958a). Liassic Volsella. Mytilus and trigonia !zosoureusis beds. It is the first some other Dysodont Species in Japan. Liassic species of Burmesia. Several Ibid., N. S .. 1Yo. 29. fragmental specimens were procured -- (1958b). A Review on the Liassic so also at Niranohama of Shizukawa area. called "Cyrenoids" in Japan. japan. four. Geo!. Geogr .. Vol. 29. Nos. 1-3. -- (1958c). Some Hettangian Pelecypods Heferences from the .. Trigonia-sandstone '' of the Shizukawa Group in I\orth Japan. Ibid., ARt: ELL. W. J (1930a), The generic Po:oition foe. cit. and Phylogeny of some Jurassic Arcidae. -- (1958d), Supplementary Descriptions of Geol. 1Hag .. Vol. 67, the Liassic Pelecypods from the Kuruma -- (1930b. 1933). A l\·Ionograph of British and Shizukawa Groups in Japan. Trans. Corallian Lamcllibranchia. Palaeontogr. Proc. Pal. Soc. Japan. N.S., Ao. SO. Soc. London. I;-;M, Y. and TAKAHASHI, N. (1940). On the BRA:'\SO:". C. C. (19"12). Parallelodon, Gram Geology of the Southmost Kitakarni matodon and Cosmelodon. four. Pal., Vol. !'v!ountainland. Cont .. lnst. Geo/. Pal.. Toholm 76 Itaru liAYAMI Imp. Unit• .. No. 33. (in Japanese). und lVIisol. Palaeontogr . .Supple. 4. Lief 2. KnHm.\, T. (1951). Some Pectinids and a LISSAJOUs, M. (1923). Etude sur Ia Faune Limid from the Jurassic Torinosu Group du Bathonicn des Environs de Macon. in Japan.]our. Pac. Sci .. Unit!. Tokyo, Sec. Tra1!. Labor. Geol. Fac. Sci. Lyon. Fasc. :;, 2, Vol. 7. Pts. 6-10. ilNm. 3. KoBAYASHI. T. (1948). Tectonic Geology of .1\I.'\KSV>', I-I. (1914). Description d'Especes Japanese Islands. Tollyo. (in japanese). nouvelles des Terrains paleozoiques et --,KoNISHI, K.. S.\TO. T.. HAY.-\~11. I. and triasiqucs du Tonkin. Mhn. Serv. geol. ToKUYA:-.IA, A. (1957). On the Lower lndochine. Vol. 3, Fasc. 2. Jurassic Kuruma Group. ]our. Geol. Soc. -- (1921). Nouvelle Contribution a !'Etude japan. Vol. 63. No. 738. (in japanese). des Faunes des Terrains gothlandiens. -- and :\loRI, K. (195·1). Studies on the devoniens et rhctiens de Ia Region de jurassic Trigonians in japan. Part 2. Ia Basse Riviere noire. Ibid .. Vol. 8. Fasc. Pmsogyrotrigonia and the Trigoniinae. 1. japan. ]our. Geol. Geogr., Vol. 25. Nos. NAKAZA\\'A, K. (1952). A Study on the Pele 3-4. cypod-Fauna of the Upper Triassic KRUMBECE, L. (1913), Obcre Trias von Buru Nabae Group in the ~orthem Part of Explanation 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 77 Kyoto Prefecture. Japan. Part l. Mem. TERQliE~I. 0. and PIETTE, E (1868). Le Lias Col/. Sci .. Unit•. Kyoto. Ser. B, Vol. 20, .Vo. inferieur de I'Est de Ia Fran(.;c compre 2. nant Ia Meurthe. Ia l\loselle. le Grand· - (1956). Op. cit. Part I. Ibid .. Ser. B. Vol. Duchc de Luxembourg. Ia Belgique et Ia 23, No.2. Meuse. iW:m. Soc. gi:ol. France, Ser. 2. NEWELL, N.D. (1938). Late Palaeo;wic Pele· Tom. 8. cypods. Kansas Ceo/. Surv., Vol. 10. VoGEL, F. (1900), Neue l\lollsken aus dem 0:-.;L'KI, Y. (1956), Explanatorr Text of the Jura von Borneo. Samml. Ceo/. Reiclts· Geological Map of I wate Prefecture, vol. !\Jus. Leiden. Ser. 1. Bel. 6. He/1 2. 2. lu:ate Pref. (in Japanese). WA:":>:ER,]. and K:-~JPSCHEER. II. C. G. (1951), PATTE, E. (1922). Etudes de quelques Fossiles Beitriige zur Palaontologie des Ostindi· paleozoiques et mcsozoiqm:s recuei II is schen Archipcls. XX. Neue Ver:;teiner· en Indochine et au Yun-nan. Jlhn. Sr>rz•. ungen aus den norischcn .iVucu/a-Mergeln giol. Indochina. Vol. 9. Fasc. 1. Yon Misol. Neues ]a!Jrb. f Ceo/. 11. Pal.. Qut:?>:STEDT. F. A. (1858). Der Jura. Tiibin!Jt!ll. Abh., Bd. 94. S,\L'RJ:>:, E. (1941). Lamellibranches du WARRr·:N, I'. S. (1932). A nt:w Pelecypod Fau Trias superieur de Hoa-Huynh (Sud· na from the Fernie Formation. Alberta. Annam). Bull. SenJ. gcol. lntloc!tina, Vol. Trans. Roy. Soc. Canada. Ser. 4, Vol. 26. 26. Fasc. 3. Y t\JJE. H. and S,\To, S. (19·1:!). A new Bivalve SowERIIY. ]. (1818. 1821). The l\lineral Con· from the Jurassic Torinosu Series of the chology of Great Britain. Vols. 2 and 3. Abu kuma Mountainland. Proc. Imp. Acad. London. Tokyo, Vol. 18. ~vo. 5. ST. .\ESCJJE, K. (1926). Die Pectiniden des Sch· YoiWYA~IA. 1\I. (1904). On some Jurassic Fos wabischen Jura. Ceo/. Pal. Abha11dl., N. sils from Rikuzen. four. Colt. Sci, Imp. F. Btl. 15. 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 JAPAN IT ARU I-I AY Al\U Geological Institute. Univ~:rsity of Tokyo Soon after my reYision (1958) had been terior laterals are double in the right published, 1 read CAsEY's (1955) of Neo valve and single in the left as in Neo· miodonticlae. nov. His new family. which miodon (single in the right and double includes Romiodon Cox. 1935, My rene in the left in Myrene). It is presumably CAsEY, 1955. Cyrenopsis ETHERIDGE, l!l02 transitional between Eotrapezium and and Jlfusculiopsis l\1."-cNEIL, 1939 besides Neomiodon (or 11fyrene) and located also Neomiodon Fiscii"R. 1887 (=Protomiodon in the Neomiodontidae. It bears impor· AxoERsn:-.- and Cox, HJ.18). and may be tancc on phylogeny that the family is the forerunner of the Corbiculidae. Ac well represented already in the Lias of cepting his opinion, I transfer Eomiodon Japan. lmmlal us. E. uu/garis. E. sp., E. (?) ![ig anteus 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) 1. (CAsEY. p. ~10, figs. 1-3) but for the Tv:-:t-figs. Hinge structures of F.omiodon worse-defined cardinal tooth 5b from llmulatus (Ym; OYAMA) nymph and developed lateral Pili. Other R: rvstored from a right internal mould features are diagnostic of the genus. (MM 2837) :-, l. Liassic Cre11otrapezium kurumense H,\\',\· L: restored from a left internal mould :-.11 is allied to Neomiodon as well as Eo (!\I~I 28·11) xl. 2. trapezium. l n the carinated trigonal out line and position of cardinals it seems Heferenees more similar to Eotrapezium but to CASI"·· R. (1955). The Neomiodontidae. a Neomiodou in the lateral teeth. Com· new Family of the Arcticacca (Pelccy pared with CAsEY's hinge of Neomiodrm poda). Proc. J1falac. S(lc. London, Vol. 31, (p. 210. fig. 7), the inner lateral teeth Pts. 5. 6. are more distinctly crenulated. In this HAY .-\~11. I. (1958), A Review on the so-call· respect the Japanese species is closer cd Liassic "Cyrenoi 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:o lf/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 the Introduction and Acknowledgements type locality. In this paper several corals collected II ere I thank Professors Haruyoshi from the Permian Mizuyagadani and Ft·JI:\IOTO and \Yataru H.\sHJ:-.!OTo of the Sorayama formations developed at Fuku· Institute of Geology and Mineralogy, ji, Kamitakara Village. Yoshiki County, Tokyo University of Education for their Gifu Prefecture (lG6 19S7) are described kind guidance throughout the present and their stratigraphic significance is dis· study. Acknowledgements are due to cussed. The Lower Permian l'viizuyagadani Professor Kotora HATM of the Depart· formation is roughly subdivided into ment of Geology, Faculty of Education. the lower or Pseudosclumgerina-limestone Tohoku University for his encourage· and upper or clastic sediments. The ment, and Professor :vrasao 1\-I,:-:ATO of next younger Sorayama formation con· the Institute of Geology and Mineralogy. sists of a remarkable basal conglomerate Hokkaido University for his advice re· (Osobudani conglomerate) conformably ceived in 1!153. and l\Ir. Tadao KAMEl of overlain with agglomeratic schalstein or the Institute of Geology. Shinshu Univ· volcanic conglomerate (Sorayama con· ersity. for his cooperation in the field. glomerate and schalstein). Thanks are also due to the ?vlinistry of The corals treated herein are Soch· Education. Japanese Government and the kineophyllum japoninmz k6. n. sp. and S. Asahi Press for grants from their japonicum pauciseptalum ko. n. subsp. Scientific Expenditure Funds awarded from the calcareous tuff bed developed to Professor II. Ft7JI:o.IoTo. in the l\fizuyagadani valley: Ammufo· phy/lum sp. from the thin conglomerate Stratigraphical Note or conglomeratic shale of the middle The two new forms of Sochl~ineop!zyl· part of the lVIizuyagadani formation fum were collected from a green and dewloped at the junction of the Taka· red calcareous tuff bed in the lower dani and Osobudani valleys ; Iranophvf. part of the Mizuyagadani formation. fum I unicafum leo. n. sp.. !Veutzeteila which directly covers the Pseudo.~ch· osobudaniensi.~ leo. n. sp., and Lonsda!eia· zmgerina·l imestone. This about 10 meters stmea? sp. from the limestone pebbles thick bed at the type section which * Recei\·ed Sept. 25. 1958. read Feb. 2, 1958. yielded abundant specimens of brach· 79 so Jlisayaslzi [G(; iopods, corals, bryozoans, and fragments rocks. Amandophyllum sp. also occurs of crinoid stems, graded upwards into from the limestone breccia of the same tuffaceous shale. Recently K..\~IEI (1951) horizon. This unnamed species is some described f1/erophyl/um hideuse 1\,,~.JEI what related to ilmandophyl!um camicum and Huangia mizuyagadaniensis 1\. A ~• E 1 (HEI~ITSCH) which was reported from the from this heel.* He a!so reported on the Upper Auernig series (Cpper Kalkreich occurrence of Squamularia asiatica C11.\0, group) in the Carnic Alps, Austria. The Spiriferella cfr. salteri Tscm::n:--;yscJIEW brachiopods listed by KA:-.mT are rather and other unidentified brachiopods. 1\A long range types and are not restricted r-.IEI insisted that the coral-brachiopods to the Artinskian. faunule belongs to the Zone of Para On the other hand the corals from fusulina and, therefore, is Artinskian in the limestone pebbles of the Osobudani age. However, I consider that the larger conglomerate indicate the late Early part of the l'vlizuyagadani formation may Permian or slightly younger age than represent the Zone of Pseudosclucagerina the 1\iizuyagadani. Irmzopltyllum tuni and is, therefore. Sakmarian in age from catum Ico, n. sp. resembles [. sp/endens the following facts. DoL·cLAs from the Lo\\·er Permian of Soclz!?ineoPhy!lum japonicum ld3. n. sp., Tapi leh Valley. Darrell Dazen. Southwest and S. japonicum pauciseptatum leo, n. Iran. In the present area it is associat subsp. from the calcareous tuff bed re ed with Pseudofusulina dujJ/itlzecata Teo. semble S. arliense ISosJJKI:-.A) and S. ten P. spp .. Nmzkine!la kotakie11sis IFL·JJ~IoTo uiseptatum (SosHKJ:--;,,) from the Artins and K .. \ \L\DA). N. lwzcadai (lt;6) and others kian of the west slope of the northern rlcA 195Ga. h). Although !Ventzelella Urals. Soviet Russia, hut our forms are osol111daniensis Jd), n. sp. and Lonsda!ei specifically distinct from the latters. astraea ? sp. are not sufficient for deter Recently I found Pseudofusulina vulgaris mination of the geological age they may (ScHELLWJEK) and other related thick represent a slightly higher position than walled-type Pseudofusulina from the Iranophyilum. These corals were appar matrix of the conglomerate or conglo ently derived from the I\lizuyagadani meratic shale lying slightly above the formation before the deposition of the Sochkineoplzy/lum-bed. Although rare Osohudani conglomerate. It should be they are favorably preserved in tine made clear that no fossils have been grained shale and based upon the mode collected which definitely indicate the of occurrence, these fusulinids may be existence of the Zone of Parafusu/ina contemporaneous or penecontemporaneous from the pebbles of the Osobudani. Un· with the deposition of this bed. The fortunately the age of neither the Sora same fusulinids are common in the Nyu yama formation nor the Osobudani con kawa group which is widely developed glomerate can be determined with ac in the south of the present district and curacy, hut there remains a great pro they are frequently associated with bability that either the Zone of Para abundant Pseudosc/ucagerina. This faunal fusulina is represented in only the up relationship is known from other local permost part of the i'vhzuyagadani and ities of the japanese Lower Permian was partly denudated during the pre Osobudani hiatus or that the Sorayama * It is doubtful that the latter species was corresponds to the Zone of Pamfusulina. derived from this bed. 361. Permian Corals from Hida Massif 81 Description of Species maturity. insertion of metasepta and less distinct cardinal fossula. It is easily Family Polycoeliidae RoniEI~. 1883 distinguishable from S. tenuiseptatum Subfamily Polycoeliinac RoEMER. 1883 (Sosiii-:It"A) by the more distinct thicken ing of the major septa near the axial Genus Sochl?ineophyllum GRAB,\"· 1928 edges and well deyeJoped tertiary septa Sochkineophyllum japonicum lc1\ n. sp. in the Fukuji species. Occurrena :-The \1izuyagadani Val Plate 8. figures 4a, b. Icy: middle part of the lVIizuyagadani Corallum solitary: corallitc small. formation. slightly curved cylindrical with turbi Geological age :-Earl~.. Permian. the nate proximal part. Diameter of coral Zone of Psr'udoschtcagerina. lite 13 mm and length about 40 mm at Reg. nos.* 21003 (Holotype). 21013 maturity. Outer wall rather thick and (Para type). externally with well de,·eloped concen- 1ric rings. septal grooves less distinct. Sochllineopilyllum japonic 11111 l\Iajor septa ~6 in number at diameter pauciseptatum IG6, n. subsp. of 13 mm. and ~2 at 9 mm. The~· are arranged more or less pinnately, con Plate 8. figures 5a. b. 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. Dia Corallum solitary, corallite cylindrical meter of corallite 12 mm to 15 mm in and moderate in size. External charac mature stage. External character un ters unobservable. Epitheca very thin. observable. Epithec.:a almost erroded Diameter of corallite 20 to 17 mm at av.·ay during fossilization. thus detailed maturity. characters remain unknown. Septa numerous. those of first order Septa consists of two orders of major 30 in number, long. extending to near and minor. Major septa 2fi in number, center but not united with columella, extend to central column. thickened by strongly thickened by stereoplasmic de secondary deposits, and almost straight. posits in intrathecal region, partially l\linor septa alternate with the former, diverging. thin in proximal part. Second short. about 1/3 as long as major ones order septa more numerous but shorter and restricted in peripheral region. than those of first order, more than 1/3 Central column occupies rather wide as long as the former and coalesced 361. Permian Corals from llida Massif with each other in intrathecal region. former has we II developed fourth order Third order septa shorter and restricted of septa, carinated septa more complicat in periphery. fewer than those of second ed columella and steeply arched axial order. and about 1/2 length of the lat tabellae and the septa are more strongly ter- Fourth order septa very short. thickened by stereoplasmic deposits in equal in lengh, and restricted to very the middle and distal parts. It also re narrow marginal area. All septa carinat sembles I. carcinophy/loides DoL'GLAS ed and somewhat zig-zag in dissepimental from the same locality and !. Permicum area. Columella occupies about 1/5 the l\J,x,\To from the Sakamotozawa series diameter of corallite. consists of median of the Kitakami \[assif. northeastern plate. radiating septal lamellae. and japan. but the present form is distin steeply arched axial tabellae. Dissepi guishable from the latters in the pos mental area wide and arranged concen session of a greater number of orders trically. of septa. In longitudinal section dissepiments Occurrence :-From the pebbles of the rather irregular in size and their convex Osobuclani conglomerate. the Osobudani sides faced upwards and i nwarcls. Valley, associated with Pseudofusulina dup!itllecata leo, P. spp., Nankinella kota kieJJsis (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. Corallum massive. cerioid: coral!ites rat her large, hexagonal. pentagonal or octagonal in shape at maturity. Dia meter of corallite about 7 to 1~ mm. External wall originally thin but more or less thickened by stereoplasmic de posits 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 Tcxt·figurc 1. stage one septum (counter?) is jointed with median plate. gradually thickened Remarks :-lranophyllum tunicatum ko, intrathecal area and thining towards n. sp. resembles I. sp!eudens Dou(;J.As distaly, second order septa about 1/2 to from the Lower Permian of the Tap i leh 31'1 as long as those of the first order Valley, Darreh Dazden, Southwest Iran and more numerous. Third order septa (Persia) in many respects. However. the very short, thickened by stereoplasmic 84 I-Iisayoshi /Go deposits near wall and restricted to marginal part of corallite. Fourth order Genus Lo11sdaleiastraea GERTH, 1921 septa frequently appear but not through Lonsdaleiastraea ? sp. out. and very short. Columella not large. oval in transverse section, well Plate 8. figure 2. circumscribed and consists of thick Corallum massive. corallite cerioid median plate. three to five rows of axial partly thamnasteroid and aphroid, sub tabellae. and few septal lamellae. and dis tel ragonal or pentagonal in shape. and tinct median plate is jointed with one about five to eight in diameter. major septum in early stage. Major septa 17 to 18 in number. long, Dissepiments arranged concentrically, reach to near center. some of them con in rare cases they form interrupted tinue with columella. :'Viinor septa al septa where major ones are discon· ternate with major ones. shorter. and tinuous. about 2/3 to 3/5 length of major, third Remarlls :-The present new form is order septa appear. but thinner. fewer closely related to rv. szecliurmellsis H L';\ i'o'G and almost rudimentary. These septa in many respects. but the Fukuji species are interrupted by vesicular dissepi has a distinct median plate in the co ments, slightly zig-zag or straight. Co· lumella. Also it differs from W. hila lumellar structure obscure owing to kamiensis YAB:o: and l'vlJ;.;.,,.o by the same strong stereoplasmic deposits. Dissepi character and shorter fourth order septa. ments about 1/2 as wide as diameter of The Fukuji sepccies is distinguishable corallite. and arranged concentrically or from TV. sel?ii 1\IJc;ATO in possessing partially lonsdaleoids. quaternary septa and a median plate. Remarks :-The species is referred to Occurrence:-The same as the preced Lousdaleiastraea with some reservations. ing species. TlH' type species of this genus L. z·inas· Geological age:·-· Early Middle Permian? sai GERTH and other Timor species are or late Early Permian. en! irely devoid of external wall but the Reg. no. 20·1n 1Ilolotype). present 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 section in 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 Plate 8 AoKI and l eo Photo. 361. Permian Corals from Hida Massif 85 pear. Such characters are recognized HtLI .. D .. 1956, "Rugosa" in MooRE's Treatise sometimes in certain species of lVeut on I nvertehrate Paleontology. Pt. F; Geol. zelella, however, the columella is more Soc. America. related to those of Lonsdaleiastraea. HtJAl'G. T. K .. 1932, Permian corals of South Thus the present one has characters of China: Pal. Sinica. ser. B. Vol. 8, fasc. 2. pp. 1-163, pis. 1-16. both of these two genera and may be Ico. H .. 1956a. 1\otes on the Osobudani con an intermediate form. The present glomerate and some lower Permian fu species may he new to science but more sulinids contained in its limestone Peb specimens are necessary before conclu bles. Pt. 2; Sci. Rep.. Tokyo Unit·. Education, sive decision be given. Sec. C. Vol. 4. pp. 293-302. pis. 18-19. Occurrence and geological age:-The --, 195Gb. Ibid .. Pt. I : Proc. Trans., Pal. Soc. same as TVentzelella osobudaniensis leo. japau. N. S .. No. 21. pp. 169-174. pl. 27. Reg. no. 21014. --. 1957. Fusulinids of Fukuji. Southeastern Part of the llida Massif. Central Japan: References Sci. Rep., Tokyo Unit•. Education. Sec, C. Vol. 5, No. 47. pp. 153-246, pis. 1-15. DoL'GLAS.]. A .. 1936. A Permo-Carboniferous IC\!\!EI, T., 1957, Two Permian corals from fauna from Southwest Persia (Iran): Pal. the Mizuyagadani formation; four. Slzilt Indica . .V. S .. Vol. 22. No. 6. pp. 1-59. pis. shu Unit•., pp. 29-35. pis. 1-4. 1-5. LEED. II., 1956, Permian reef-building corals GERTH. II.. 1921. Die Anthozocn der Dyas von from North Auckland Peninsula, New Timor: Pat. t·on Timor, Lief. 9. ilbt. 16. pp. Zealand; llu/1.. New Zealand Geo!. Surv., 65-147, pis. 145-150. No. 25, pp. 15-24, pis. 1-6. GRAB.\t:, A. W .. 1928. Paleozoic Corals of Mll'ATO, M., 1955, Japanese Carboniferous and China: Pt. 1, Tetraseptata; Pal. Sinh·a, ser. Permian Corals ;Jour. Hokkaido Univ. hzst. B, Vol. 2, fasc. 2. pp. 1-151. pis. 1-8. Geol. Min., No. 540, pp. 1-202. pis. 1-43. IIERITSCH. F .. 19313. Korallen der Mo~kauer-, WAAGEN, 'IV. and '0lE:"TZEL, ]., 1886, Salt Gshel-und Schwagerinen-Stufc der Karni Range Fossils, Vol. 1, Productus-!imestone schen Alpen: Palaeon/ogr., Bd. 83. Abt. A. fossils. 6, Coelenterata; Pal. Indica, ser. pp. 99·162. pi;;. 14-18. 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 OF SENDAI: 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 Introduction and Acknowledgements in 1935 and from the Otsutsumi forma tion at Otsutsumi, Taiwa-machi, Kuroka Pecten su:iftii BER:'-i.\RDI (1858). a com wa-gun. l\liyagi Prefecture in 1937. mon Recent scallop in Northern Japan, However, it is considered that YoKOYA has been recorded from numerous locali :-.rA's single right valve from Koshiba ties of the Neogene and Pleistocene is a synonym of Ch!amys cosibensis CY oKo formations of North Japan. Among the YA~tA) which was described from the Japanese i\'iiocene Pect iniclae this species same locality at an earlier elate, and the is interesting because of its long geo single right valve from Obashira proba logical range from the Early Miocene bly represents a new subspecies of and because of its confusing characters. ChlaiJiys cosibensis which will be descri The fossil swiftii in Japan was first bed at another opportunity as Chlamys described from the .. Taga '' formation cosibensis lianzazcae MAst:oA, n. subsp., at Hatsuzaki. Hitachi City, Ibaraki Pre and the single right valve reported from fecture by KocH!BE (1882). Subsequently 6tsutsumi is Clllamys cosibensis lumzazcae, YoKOYA:\L\ described it from the Koshi though specimens referable to szt'iftii ba formation at Koshiba, Yokohama have been collected from the same City, Kanagawa Prefecture in 1920, from locality by No:-.JuRA and l-L\TA 1. In the the'' Taga" formation at Tsurushihama, present article the reports with illustra Hitachi City in 1925. from Obashira. tions were reviewed but those \vith only Chichibu City, Saitama Prefecture in listed occurrences were rejected because 1925 and from the Sawane formation at the original specimens could not be Sawane, Sawada-machi. Sado-gun, 1\iiga studied. ta Prefecture in 1926. No::-!l'RA and Numerous .Recent and fossil specimens IlATAI described it from the Daishaka were studied, and these included those formation at Daishaka, Namioka-machi, now preserved in the collections of the * Received Oct. 14, 1958; read at the 7lst. Department of Geology, Faculty of Edu meeting of the Society at Kyoto. Sept. 27, cation, in the Institute of Geology and 1958. Paleontology, Faculty of Science, both 8G 362. 111iocene Pectinidae from the Envimns of Sendai 87 of the Tohoku l:niversity, and in the GR:\"'T and GALE. Mem. San Diego Soc. Saito I-Io-on Kai l\luseum, all in Sendai Nat. Hi st., Vol. 1. p. I il, pl. 10, figs. City. The results of examination on the la-b. 4a-b. Recent and fossil su:ijtii and its geologi 193-t. Chlamys swijtii (BER:'\ARDI), KINOSHI cal significance are presented herein. TA and IsAHAYA. Rep. Fish. Sun; .. Hok kaido Fish. Exp. Sta .. No. 33. p. 14. pl. Acknowledgements arc due to Dr. 10, fig. 7-L Kotora l-1.-HAI of the Department of 1935. Pecten (Pallium) Slcijtii BERN.-\RDL Geology, Faculty of Education, Tohoku ~Ol\ll'RA and HAT.-\1, Saito flo-on Kai University, for kindly supervising the :l!us .. Res. Bull.. J\"o. 6, p. 98. p!. 9, fig. present work and also to l\'lr. Shin-ichi 8, pl. 10, figs. 3. 4. pl. 11. fig. 8, pL 13, HoN:-.IA of the Kanazawa High School at fig. :t Kanazawa. Sado Island, l\i igata Prefec 1950. Clzlamys islandicus var. Sl!'iftii (BER ture, for his assistance in collecting N.-\RDI), Kl:BOTA, Sliinseidai-no-Kenkyu specimens. (Cenozoic Research). No. 6. p. 12. pl. 9. figs. 66. 67 HJ5L Clz/amys swi[tii (BERNARDI). TAJ-:1 in Description HrRASE. lltust. llandb. Shells Nat. Color, Family Pectinidae Jaj>an. Adj. Ten·it., pl. 12. lig. 5. 1951. Ch/am_1•s Slcijtii (BER:-\ERDI), H.\BE, Subfamily Pectininae GeneraJajxm. Shells. No. 1. p. 74. fig. 150. 1955. Chtamys su·ijtii (BER?\ARDI), HAHE, Genus Ch!am_rs (BoLTEr-;) RooJr-;G, 1798 Pub!. Akkeshi Mar. Bioi. Slat., 1\'o. 4, p. I 6. pi 2, fig. 7. Subgenus Swiftopecten HERTLEIN. 1935 1955. Ch!amys su.iftii (IkRN.\RDI). KIRA, Color. lllust. Shells Japan, p. 99. pl. -19, Clllamys iSu:i_ftopecten) swiftii fig. 1-!. (BERN\RD!), 1858 1958. Clzlamys (Su·iflo}Jecten) su:ifli (BER- 7'ARDI). HABE. Pub!. Se/o :Uar. Bioi. Plate 9. figures 1-1. Lab .. Vol. 6, No. 3, p. 263. pl. 1:?, fig. 18. 1867. Pecten stciftii BERl\ARD!. SCHRE"'CJ'. Shell large and thick, much higher Moll. 4mttrl. }·iordjap. Jleereas. p. 487. than long, moderately inflated. inequi pl. 21. ligs. 1-:.l. lateral, posterior side longer than ante 188:?. Pecten striftii BERNARDI. KoCHIBE, Rika Kai-s!ti. Tokyo Univ. Press. No. 4, p. i5. rior, postero-dorsal side nearly straight pL 5. fig. :3. and antero-dorsal side gently curved, 1888. Peden Slr~flii BERI"MWI. KOSTER und ventral margin uneven corresponding to KoBELT in l\1ARTI7'1 unci CHE~INITZ. external sculpture; left valve somewhat Syst. Conch. Cab .. Vol. 7. Pt. 2. !J. 1-!2. more convex than right; both valves pl. 40, fig. 3. radiately ribbed and forming a!1 angle 1902. Pecten s~riftii BERN., YosiH\\'ARA. Zoot. of about 70° at apex . .llag. Tokyo, Vol. 14. No. 162, p. 1-U, Right valve with four, rather promi pl. 2. figs. 6a-b. nent. round-topped radial ribs, two sub 1925. Pecten su·ijlii BERNARDI. YOKOYA\IA. ordinate radial ribs near submargins, Jour. Coli. Sci .. Imp. Unit'. Tokyo, Vol. -15. Art. :), p. 27. pl. 2, fig. 1. intercalary threads and concentric 1926. Pectell S/VIjtii BERNARDI, Ym.;oy_~~IA, growth lines. and ornamented by rather Jour. Fac. Sci .. Imp. Univ. Tokyo, Vol. distinct fine network; radial ribs broader 1. Pt. 8, P- 303, pi. 37. figs. 5. 6. than their interspaces. gently bend an l931. Pecten (Pallium) su·iftii 13ER:'-IARDI. teriorly towards ventral margin, sculp- 88 Koichiro MASUDA tured with several, nearly equal, fine centric growth lines. and ornamented radial threads \vhich are separated by by rather distinct fine network; radial shallow and narrow longitudinal furrows ribs narrower than their interspaces, and usually bifurcate towards ventral and sculptured with several. rather margin. but sometimes backs of radial faint, fine radial threads which are near ribs rather smooth; two subordinate ly equal to their interspaces and rare radial ribs near submargins separated ly divided into two parts by a shallow from main radial ribs by shallow and longitudinal furrow near ventral margin: narrow interspaces, usually slender and intercalary threads seven to ten, nar obsolete, and sculptured with a few. ro·wer than their interspaces on upper faint, fine radial threads; four to six half of disc but nearly equal at ventral intercalary threads between radial ribs margin. and rarely divided into two sometimes bifurcate near ventral margin. parts by a shallow longitudinal furrow and nearly equal to radial threads of near ventral margin; primary intercalary backs of radial ribs in strength at threads three to four near beak and in ventral margin; primary intercalary crease their number towards ventral threads two or three near beak. increase margin; concentric constrictions usually their number towards ventral margin; conspicuous, by which radial ribs appear submargins sculptured with numerous. nodose; anterior auricle triangular in faint. fine unequal radial threads which shape. and sculptured with several. dis are fainter and finer than those of cen tinct. elevated radial threads. somewhat tral part of disc: concentric constric Jess distinct intercalary threads and tions rather distinct: sculpture of backs rather distinct concentric lines, by which of radial ribs usually more distinct at radial threads appear somewhat nodose; ventral margin and concentric plait than posterior auricle similar to anterior in those of other places: anterior auricle sculpture. though radial threads much very large. nearly triangular in shape. less distinct than those of anterior. much larger and longer than posterior Interior surface of both valves distinctly one. furnished with rather deep and or gently folded corresponding to exter wide byssal notch, rather narrow byssal nal sculpture and with fine serration at area, and sculptured with several. more ventral margin. or less elevated. distinct radial threads. Dimensions :-Shown in Table 1. somewhat Jess distinct intercalary Comparison and Affinity :-Chlamys threads and concentric lines; posterior (Swijtopecten) parme/eei reported by D.uL auricle similar to anterior in sculpture. (1898) from the Pliocene of Caliiornia though radial threads less distinct than and Chlamys (Szcijtopecten) l?indlei des those of anterior; hinge with rather cribed by DALL (1920) from the Pliocene simple cardinal crura. rather distinct of Alaska are closely related to the ctenolium. and deep and wide resilial present species, but as pointed out by pit provided with elevated. distinct D.\LL (1920). the former differs from lateral ridges; hinge plate rather fiat the present one in having a smaller and wide. and sculptured with fine. faint shell and peculiar microscopic squa striae parallel to hinge line in adult mation, and the latter by the lacking of specimen. Left valve with five, promi concentric waves due to the resting nent. round-topped. rather smooth radial stages. The present species also rescm ribs, fine intercalary threads and con- bles 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: ...... :::: '" It' '" ro :J ro 0(, ;:j) .::-! > u w '" "' I B i > 0 ~ 0. -;;:; 0 0. d ..J J < > I ..J I < > ----- A ]1_1_ 131 110 55 20.5 75' R c 36 27. 5 17 4. 8 70' L ! II 115 97 24 70' R I 35 30 - 6. 7 70' L 111.5 98 ·19. 5 ' 20. 5 70" R II 34 29 18.5 7 70' I L I 100. 5 87.5 21. s , 70' R D - 845 -- 15 70' R 79 68 34 14 1 70' R E 92 - 45 29 70' I L 39 29.5 17 6.8 70" R F 96 79 43.5 I 18.5 70' I R 35 29.5 16 65 70' R I G 103 86 50 21.5 70' R+ I 35 28 7 70' L N 103 86 50 25.5 70' L+ B 1 68.5 53. 5 11.2 70' R~ H 89 75 '12. 5 14.3 70' R+ 57. 5 47.8 25 11 70' R I• 89 75 42.5 19 70' L+ 57 43 26.5 10.7 70' R II 88 76 41. 5 14 70' R+ I 5:'!.5 44 28 10. 5 70" R I " 88 76 4J. 5 I 17 70' L+ 26.6 21.4 4. 2 70' R ! II 75. 5 63 34 10.9 70' R 99 81 23. 5 I 70' L I 88. 5 69 43 18. 2 70" L ! " 96.8 81 39 ' 23 70" L I I 101 88 58 21 70' ,. I R+ 50 40 8. 5 70' L I II 101 88 58 25.5 70' L+ c 91.5 80.5 42 18 70' R J 89 75 46 14.7 I 70' R+ 91 76 70' II 41 I 22 I R 89 75 46 I 20. 5 ' 70' L+ 81 65 33. 5 15 70' R K 111 94.5 48 25 70' R I i I I 76 70.5 34 , 15.5 1 70' R /1 105 91.7 48 I 24 70' R I II 76 63 34 , 15.5 I R I 103 93 52.5 I 23 70' R+ " I I II 30 24 16 : 6 70' R II I 103 93 52.5 28 I 70' L+ 17.5 14. 7 I 2. 8 I 70' R /1 102 88 - 21. s I 70' L I I 63 I 52 17 ' 70' L L 120 101 50 20 70' R ' 40 33 18 1 7. 5 : 70' L II 119 100.5 59.5 28.5 ' 70" ' L II 36 29.5 : 6 75' L II 100 88 52 26 70' L I I ---- +: Intact valves. A: Daishaka, Namioka-machi, Minami·Tsugaru·gun, Aomori Pref. (Plio cene). 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. Toda mura. Ichihara-gun, Chiba Prcf. (Pleistocene). G: ?v1anui, cast coast of Southern Sagha· lien (Recent). H: Dui-March, Northern Saghalien (l{eccnt). I: Shizugawa. Motoyoshi gun, Miyagi Pre f. (Recent). J : Kescn-nurna. Miyagi Pref. (Recent). K: Mutsu Bay. Ao mori Pref. (Recent). L: Shimpo, Kankyo-Nando. Korea (Recent). !10 Koichiro M11SUDA var. monmi which were described from line in the right valve. The left valve the Pliocene of California by ARNOLD is characterized hy its five (rarely four (1906). but it can be distinguished from or six) conspicuously prominent, round the former by its posteriorly contorted topped radial ribs which are usually shell. smaller number of intercalary nodose and by its young shell which is threads, shape of auricle and rather nearly fiat or rarely a little concave large posterior auricle. and from the upwards. As pointed by YoKOYA~t.\ latter by the above mentioned charac (1926) and ~OMURA and lhn1 (1935), the ters and rather less distinct radial radial ribs sometimes become strong threads on the backs of radial ribs and and elevated but may be low and flat in their interspaces than those of the tened. Sometimes the sculptures of present one. From Chlamys etche~;oini radial ribs are obscure. especially in the which was described by AKDERSOK (1905) case of the conspicuously nodosed radial from the Pliocene of California, it is ribs of the left Yah-e. distinguishable by its smaller shell and Some differences between the fossil the characters of the radial ribs. This and Recent specimens arc observed. In species much resembles Chlamys the Miocene specimens the radial threads cosibensis which was described by Yo on the backs of radial ribs and in their IWY,\~IA (1911) from the Pliocene Koshi interspaces of both valves are usually ha format ion, but it can be distinguished more numerous and more close-set than from cosilie1z.~is by its large. posteriorly those from the Pliocene. Pleistocene and contorted shell which is much higher Recent, and the fossil left valve is than long, smaller apical angle. triangu usually nearly flat or rarely more or Jar anterior auricle. hinge with rather less concaved upwards in the young simple cardin::~! crura and nearly flat stage. while the Recent shells are gent left valve in the young shell. Chlam.rs ly inflated and tend to gradually increase l?ilamurai which was described by Ko their convexity towards the ventral TAKA ll9:'ifi) from the Oligocene Isomatsu margin. and moreover. the concentric formation. Aomori Prefecture. is dis constrictions are rather less conspicuous tinguishable from the present one in the than those of the fossil shells. but the greater number of and the different characteristics except for the above mode of bifurcation of the radial ribs mentioned are quite similar to each and intercalary threads. other. In other words. the variability Remarks :--This species is characte of the left valve is more progressional rized by its large and thick. posteriorly or responds more to the environmental contorted shell which forms an angle of conditions than the right valve (~-IAst: about 70° at apex and is much higher DA, 1957). than long, four. rather prominent round Described specimens :-l{ight stream topped radial ribs which are sculptured cliff. northwest of Daishaka. Namioka with several. fine radial threads, t \\'O machi. \'iinami-Tsugaru-~un. Aomori subordinate radial ribs near submargins. Prefecture. Conglomeratic. calcareous fine intercalary threads. rather conspicu coarse-grained sandstone of the Daishaka ous concentric constrictions, Yery large formation (Pliocene). DGS, Reg. No. 3684. triangular anterior auricle, and flat Occurrence ;-Otsutsumi formation in hinge plate which is sculptured with Miyagi Prefecture and Ginzan formation faint. !inc striae parallel to the hinge in Yamagata Prefecture: Late Early 362. Miocene Pectinidae from the Environs of Sendai 91 l\liocenc. water inhabitant, though it is more or " Taga" formation in lbaraki Prefec less eurythermal. and stci[tii seems to ture and Suenomatsuyama formation in prefer a rather shallow clean sea bottom I watc Prefecture : Late l'vl iocene. of rock or gravels. Sawane and Shiraiwa formations in Some morphological differences are Niigata Prefecture. Sasaoka and Shibi observed bet ween the specimens from kawa formations in Akita Prefecture, Saghalien and those from Northern Hon Daishaka and IJamada formations in shfi. The concentric constrictions of the Aomori Prefecture. and Kami-iso and left valve from Saghalien arc somewhat Setana formations in Hokkaido: Pliocene. less developed than those from Northern Narita formation in Chilm Prefecture, Honshfi. so that. the radial ribs of the and Shishinai and Kushiro formations former are usually rat her low and flat in Hokkaido: Pleistocene (text-fig. 1). tened and the com·exity of the former Geo;.,traplzical Distribution :-~orthern is somewhat less than that of the latter. Honshli. Hokkaido. Kurile Islands. Sagha but the variability of the right valve lien, West Coast of Amurland. Tartary is rather less than that of the left valve. Strait. ~ortheastcrn horea, Korea Strait Although the number of examined speci and off Alaska. mens are not abundant, the mentioned Geological ra-1/J.[e :-Late Early Miocene facts suggest that the specimens living to Recent. in northern regions are somewhat less influenced by the variation in the Z:-1- Hemarks on the Recent swiftii nual water temperature than those liY ing in more southern areas. owing to The Recent smftii has a wide geogra the smaller thermal range of the annual phical distribution extending Northern water temperature compared with that Honshil to as far south as Fukushima of the southern area. For instance, ac Prefecture along the Pacific and to as cording to E~;\r\" (19:)3) the water on far south as Fukui Prefecture along the the continental part of the Japan Sea. Japan Sea. north"·ards to 1-Iokkaido. in the southern part of the Okhotsk Sea Kuri lc Islands, Saghalien. west wards to and the nort hem islands of the Kuri le the Korea Strait. northeastern coast of group, is characterized by an arctic tem Korea and the west coast of Amurland perature during the whole year at the (text-fig. 1\ and it is also stated to be depth below 35 to 30m. And the sur living off Alaska. The area of distribu face water temperature in the Northern tion in the Pacific is influenced by the Kurile Islands is I'C in August and Oyashio Cold Current. in the Japan Sea -1 T in February. while that of the by the Liman Stream (~orthern Korea southwest coast of Hokkaido is 15°C to Cold Current) and in the Okhotsk Sea 18oC in August and less than OOC in by the Eastern Saghalicn Cold Current February. Concerning such case Nol'.lli (text-fig. 1). However. sometimes this RA and HATM (19::16) have discussed on species lives in areas influenced by the the living Neptunea arlltritica BEI~NARDJ. warm current as l\'Iutsu Ray, Tsugaru The above mentioned data may aid to Strait. Wakasa Bay and the Korea Strait. analyse the environmental conditions of These areas arc influenced annually or the fossil stt'iftii, but further data are seasonally by the cold current. There necessary to settle this problem. fore, it is evident that szci[tii is a cold 92 Ko:chiro MASUDr1 Miocene Suenomatsuyama and "Taga" Geological Significance formations, where it is associated with As known at present, the oldest oc several rather cold water species. Abund currence of stciflii is from the Otsutsumi ant specimens of swi[tii occur from the and Ginzan formations in Northeastern Pliocene Sawane, Shiraiwa. Sasaoka, Honshu, japan, where it is rather rare. Hamada, Daishaka, Kami-iso and Setana The next occurrence of swiftii is the Late formations in association with many 148 152 , 46 Current -Sy a tem 42 38 38 34 30 .• p 30 of Recent and Fossil Chla~ys sw1ft11 124 1?8 132 136 140 144 148 Text·figurc l. 362. Miocene Pectinidae from the Environs of Sendai boreal molluscan shells as Patinopecten C/zlamys wattsi var. morcmi (ARxot.n), yessoensis (J .'\ Y ). Pododesmus macroschisrna Clz/amys cosibensis (YoKoYA~1A) and "Pec (D~-:snAYEs), Astarte a!askensis DALL, Con· ten tiggerinus" YoKov A:O.tA (not of :VTL't. c/wcele disjzmcta GAnn. Clinocardium cilia LER) also included into C/zlamys swiftii tum (FAnRtctcs). Neptzmea lira/a (G:-.tELtl'), var. etclzegoini (A:-mERso:--~) by the same etc .. boreal forms of Bryozoa (KATAOK.\, authors. Moreover, they considered that 1957) and foraminifers. Swijtii is also Clzlamys lzeteroglypta (YoKOYA~tA) which known from the Pleistocene Narita for was described from the Pliocene Smvane mation in Chiba Prefecture and from formation is a synonym of Clz!amys swijtii Shishinai and Kushiro formations in var. nut!eri (AR:--~OLD), and that C!zlamys Hokkaido. (Szcijtopecten) parmeleei (DAt.t.) is one of From the morphological difference into swijtii. Subsequently. No11n.:R,\ and between the Recent and fossil specimens HATAI (1935) considered that YoKOYA~·tA's which is but little. it is inferred that species and Clzlamys nutteri should be the present species acquired its stasi held as distinct species. The writer genesis during the late Early :Vliocene, agrees with GRA:o-;T and GALE in regard and survived to the present with little ing kindlei as a subspecies of swijtii and morphological variation. This view is with NoMURA and H,\TAt in holding the upheld from the gradual increase in the Japanese species and C!z!amys nutteri as incli vidual number of swijtii in good distinct from one another. but the writer agreement with the increase of the as is inclined to consider parmeleei as a sociated boreal fauna such as molluscs, subspecies of swijtii. It is inferred that bryozoans and foraminifers from the Chlamys (Szcijtopecten) swiflii kindlei and late Early l\Iiocene through the Pliocene Clzlamys (Stciftopecten) swiftii pamzeleei to the Recent. are descended from stcijtii (s. s.) as a Chlamys nutteri (AR:-.iOt.n) and Ch!amys result of its eastward migration from (Swiftopecten) kindlei (DAt.L) were regarded Japan to the western coast of America as the varieties of swijtii by GRA"'T and followed by localization and adaptation. GAr.r: (1931) and C!z/amys zcattsi (ARKOLD), 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: Gin zan (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 and Kumaishi. 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. 94 Koiclziro 11-fAsuDA before the end of the Pliocene. How· of North Japan. Short Papers. Ins!. Geol. ever. to settle this problem the fossil Paleont. To!zolm Unit•., No. 2. pp. 74-98. specimens of swiftii and its related forms liATAI. K. (1936), A Note on the Distribu· from California and Alaska should be tion of Certain Species of Marine lnYCI'· tebrates. Bull. Biogeogr. Soc. ]apa11, Vol. studied comparatively and more Recent 6, No. 12. pp. 123-141. specimens from the northern Pacific -- and S. Nrsl\·,\:-.L'\ (1939). Palaeontologi· must be examined. <.:al Notes on Certain Japanese Scallops. four. Ceo!. Soc. Japan. Yo!. 46, No. 544, References pp. 37-46. 3 text-figs. -- (1939). Migration of Marine Fauna in AR:- seidai-no·KI'IIIiyu (Cenozoic Research). No. the Region lying North of the Nanakita 6, pp. 12-18. 2 pis. Ri,·er. in the Vicinity of Sendai. Rikuzen KuRODA. T. (192~1-1935), An Illustrated Cata· Province. japan. Ibid .. 1\To. 13, pp. 121- Iogue of japanese Shells. Parts. 1-16. 145, 5 pis. J'emts, Vols. 1-5, Append. pp. 1-154. -- and -- (1937). On the Variation of -- and K. KoBA (1933). l\lolluscan Fauna Neptunea arthritica BER:":M~DI. from the of the Northern Kurile Islands. Bull. ~orthcrn and Central llonsy(t, Japan. Biogeogr. Soc. Japan, Vol. 4. No. 2, pp. Ibid., lv'o. 13, pp. 1-5, 2 pis. 151-170. 1 pl. -- and -- (1938). On Some Fossils from KesTER. H. C. und W. KonEL T in MARTI?'! Akita Prefecture. Northeast Honsyu, und Cllnt:-.:ITZ (1888). Die Gattungen japan. Japan. four. Geo/. Ceogr., Vol. 16. Spondy/us und Pecten. Syst. Conch. Cab., Nos. 1-2. pp. 39-6·1. 5 text·figs. Vol. 7. Pt. 2. pp. 1-296. 72 pis. Or:--;o~IIKADO, T. (1937). l\lolluscan Fossils MAst·oA. K. (1%1). A Note on Miyagipec/en from the Pleistocene Deposit of Sisinai ma/sumoriensis 1\IASllDA. Saito llo-011 Kai in Tobetu-mura. Isikari-gun, llokkaido . •l!us., Res. Bull., No. 26. pp. 31-39, 1 pl. four. Ceo!. Soc. Japan. T"ol ..J.J, No. 520. Nnl'o, H. (193·1), On the Soundings from the pp. 65-70. Bottom of the Western Part of the Tsu · OY.\:0.1:\, K (1951). On Mollusca dn~dged from garu Strait. four. Geol. Soc. Japan. Vol. off Kumaisi with Notes on Hise and Fall 41, No. 49:>, pp. 713-726. of Ocean-current. ,lJisc. Ref'· Rl's. lust. -- (1949), On the Bottom Deposits on the Nat. Re.~ .. Nos. 19-20. pp. 137--141. Banks at Mouth of \Vakasa Bay and on -- (1952). Palaeontological studies on Pec the Adjacent Continental Shelf. Japan. tens. Tbid .. No. 25. pp. 24-30. four. Geol. G!'ogr., J'o!. 2 7, Nos. 1-·1. pp. SAsA. Y. (1939), On the Kusiro Series. the 193-225. 2 r>ls. lowet· Pleistocene Deposils in Eastern Nol\!LA:"O, .f. 0. (1917). The Etchegoin Plio 1-Iokkaido. japan. ]ub. Pu/JI. Comm. I'ro.f. cene of l\•liddle California. Univ. Cal~(. H. Yabe's 60th llirthday, Vol. 1, pp. 5G9-587. Pub/. (;col .. 1/o/. 10. pp. 191-2-10. 7 pis. ScHRE!'\CK. L. (1867). Molluskt-n des Amur ::\OJ\.!l'l~''· S. and N. IIATAF: (1928), Outlines Landes und des Nonljapanischen l\'lccres. of the Distribution of Sonic Recent l\•lol· Reisen und Forsclmng :1mur/ande in dem lusca on the Coast of Korea. four. Nat. 1854-1856. Vol. 2. Pt. 3, pp. 259-976, 17 His!. Chosen, No. fi, pp. 1-9. pis. -- and II. Tst·:-.:orM (1933). Recent l\Iollusca SttGAI. K .. II. MATSU, s. SATO, Y. 1\tT:\KA\\'A, from Onahama Bay, 1-lukushima Prefec l\I. SASAKI. M. MrYASIIITA and II. !\.\\\':\· ture. Saito llo-on Kai JHus .. 1Votes. Vol. 3, em (1957). Explanatory Text of the joban pp. 1-19. Coal Field. Geologica! i\laps of the Coal --and K. IL\T,\1 (1935). Pliocene ~lollusca Fields of japan. I. Ceo/. Sun•. fa/XJ11, pp. from the Daishaka Shell Beds in the 1-H3, 58 text-figs .. 3 maps. Vicinity of Daisyaka. Aomori-ken. Xorth· YoKOYA~IA, M. (1920). Fossils from the Mi east Honsyu. Japan. Saito Ho-on Kai ura Peninsula and its Immediate ~orth. Mus., Res. Bull.. 1Vo 6, pp. 83-137, 5 pis. four. Col!. Sci .. Imp. Unh•. Tokyo, Vol. 39, --and -- (1936), A Note Concerning Data Art. 6. pp. 1-193, 20 pis. on the Bathymetric Range of Certain -- (1925). Molluscan Remains from the Marine Animals and Remarks on the Uppermost Part of the Jo-ban Coal Field. Geology of the Neogene Formation in Ibid.. Vol. 45. Art. :., pp. 1-3·1. I) I>ls. Northeast llonsyu, Japan and their Depth -- (1926). Fossil Shells from Sado. Ibid., of Sedimentation as indicated by the Fos Vol. 1. Pt. 8. pp. 249-312. G pis. sil Fauna. Ibid., No. 10. pp. 231-33·1. YosHtWARA, S. (1902), Japanese Shells (La -- and -- (1937), A List of the Miocene mellibranchs). Zoo!. Mag. Toltyo, Vol. 1-1, Mollusca and Brachiopoda Collected from 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 Plate 9 MAsuoA photo. 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 to Prof. T. KoB.:\YASHI of the Universitv I Introduction of Tokyo for kind guidance and reading manuscript. to Prof. T. !\1ATSl'~IOTO of T1·igonioides KoBA Y .\Sill and St:zc~<: 1 the Kyusyu UniYersity and Dr. K. Su:e (1936) is an important genus in the non KI of the Research Institute for Natural marine Cretaceous fauna of Eastern Asia. Resources for encouragement. They expressed an interesting opinion that its peculiarities are due to adapta tion of trigoniid to a new non-marine JI Historical review environment "·hich \vas produced bv the 1. Ko£3,\Y.-\SIIl and SLzn.:1 (1936) erect Sakawa orogeny. Subsequently it. was ed the genus in describing T. kodairai discovered from various districts on the from the Lower Cretaceous Naktong continental side of Eastern Asia. Espe series ISuimondo beds) of S. Korea and cially important is MATSl'MOTo's discov Wakino series (Rikimaru beds) of N. ery of shallow sublittoral marine beds Kyusyu, Japan. From the hinge nature from the upper Gosyonoura group in it was referred to the Trigoniidae. Its \Vhich Trigonioides bearing brackish or principal speciality in surface marking fresh water sediment is intercalated. was considered to depend on the change Now seven species are known of the of the habitat from marine to fresh genus. Previously its classification was water. made chiefly by its outline and ornament 2. HoFFET (1937) described four new but a careful comparison among num· species of Trigonioides (kobayashi. laotiae. erous specimens has shown that varia trigouus and diversicostatus) from the tion in outline and ornaments is fairlv Senonian of Laos and arrived at the con wide even among the shells from on~ ciusion that Trigonioides is a trigonoid locality. Seven species including one shell distinguishable from Trigonia in new subspecies are here recognized by a hinge teeth and surface ornament. new standpoint and their phylogenetic 3. MATsnioTo (1938) described T. relationship is discussed. kobayashii from the upper Gosyonoura The writer expresses his sincere thanks group and pointed out the difference * ReceiYctl July 28. 1958: read Feb. H. between Trigonioides and Trigonia beside 1959, at Hiroshima University. the diagnostic shell features. 98 Yoslzihisa OTA 4. Kou.-\YASIII and St:zl:KI (1940) pro· ture found all over the surface .... posed a new name T. matsumotoi for ...... T. lwdairai 2\L-\Tst::-.loTo's species because it is pre 2) Rounded in outline, and sculpture occupied by HoFFET·s. SnwKI (1940) remaining only in umbonal and post instituted a new genus. Hoffetrigol!ia erior parts .. T. kodairai paucisulcatus and placed HDFFn's four species in it. 3) Rounded in outline, and similar to ln addition, T. kodairai paucisu/catus was T. lwdairai sculpture .. T. ma/sumotoi described by SL'ZL'"' from t llc lower 4) Trigonal but more rounded than T. Siragi series. lwdaimi. and similar to T. lwdairai 5. KonAYASIII and SntTI (l\J4l) des sculpture ...... T. /aotiae cribed T. kodairai from the Lower Cre 5) Trigonal and inequilateral...... taceous Talatzu series...... T. kobayashi 6. SuzuK 1 (19,13) restudied the Nak 6) Trigonal and equilateral .. T. trigon us tong fauna with his new collections. 7) Elliptical and sculpture different The detailed features of the pscuclocar from the precedings in a few dia dinal teeth of Trigonioides were unknown gonal plications in front of umbonal at that time, but T. kadairai from the angulation ...... T. dit•ersicostatus upper Naktong shows the hinge feature In this classification, the outline and clearly. He said that its hinge fea sculpture are seriously taken for the tures are identical with those of T. specific distinction. If one examines kodairai paucisulwtus from the Siragi many specimens from a horizon, how series and agree with the essential fea ever, wide variation can be seen in out tures with those of T. matsumoloi. and line and even in ornamcntion. There its ornament is intermediate between fore, the above classification can not the typical form and paucisu/catu.~. always be applicable to Triwmioides. 7. L. R. Cox (1955) identified an inter A) Shell-outline nal mould from the lower \Vakino sub a. It has been said that matsumotoi group with T. kodairai. Because its is distinct from kodaimi in the more hinge structure and characteristic orna rounded outline. But it was found that ments are so common in the typical union ids. i. c. Castalia and Ni/Jftononaia, he withdrew new family, Trigonioididae which he had proposed in 1952. 0_ 8. KonAYASHI (1956) redescribed the (Qmm dentition 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 Tri 00 gouiaides. III On the classifkation of Trigonioides Oo Trigmzioides has been classified as fol Text-figure 1. Variation of shell-outlines lows : of T. matsumotoi, showing subelliptical, 1) Subtrapezoidal in outline, and sculp- subtrigunal and intergradational forms. 363. Trigonioides and its classification 99 several elongated specimens of the for his Plates I. ll and III to show variations mer species can not be distinguished in shell-outline. As shown in 3a and 3b from lwdairai in outline. of laotiae. they agree with lzodaimi in b. The outline of matsumotoi from subelliptical outline. Kobayashi (2) also the same horizon is fairly variable as agrees ·with the holotype (la) of trigonus shown in Text-fig. 1. Their outlines are in outline. Therefore, it is difficult to linked from subtrigonal to subelliptical distinguish lwbayaslzi fron1 trigontts by by intermediate forms. the outline. Subtrigonal and subellip c. The writer has examined only a tical forms predominate in the Laos few Laos specimens. HoFFET·s report specimens. but there may be Yariation does not give the frequency of occur to some extent. rence. Text-fig. ~ was prepared from ,__.... 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 and Wakino series is intermediate be \Vhether kodairai type ornament covers tween kodairai type ornament (a) of the all the surface or not has been lower Naktong series and malsumotoi noted, but there is tolerable variation. type (c) of the Gosyonoura. As shown in Text-fig. 3, the ornaments The ornament of the Laos specimens are classified into three types where indicates the last stage. Namely, koba suzul?ii type (b) of the upper Naktong yashi and !aotiae are similar to kodairai 100 Yoshihisa 0 T A V Systematic description of Trigonioides in the ·wakino and Gosyonoura formations. A. Wakino group The Wakino subgroup in N. Kyusyu was subdivided by the writer into the follo\dng formations in descending order: Shimonoseki subgroup ---1disconformity-- "1. Upper W akamiya formation 3. Lower Wakamiya Text-figure 3. The typical formation Wakino ornaments of Trigonioides. 2. Nyoraida I subgroup a. Kodairai type ornament. formation b. Suzukii type ornament. 1. Sengoku c. .Uatsumotoi type ornament. formation ---clino-unconformity-- type. but they lack reversed V-shaped ribs in anterior. In trigonus radial and Paleozoic Aida group concentric costae become nodose near T. paucisulcatus suzukii occurs with P. their intersections. DilJersicostatus has licatounio naktongensis multip!icatus, Bro· extraordinarily developed irregular ribs tiopsis kobayashii and Viviparus sp. at in the posterior. llata, Yahata-city. This suzukii bed be longs to the upper formation as confirm IV New classification eel by the stratigraphy and paleontology of Plicatowzio. It is noted that conjoin of Tri gonioides ed valves predominate and the arrange This genus \vhich has constantly ment of Brotiopsis is irregular in the characteristic hinge teeth is classifiable upper formation. by ornament as follows : 1) Kodairai type ...... T. kodairai Family Trigonioididae Cox, 1952 2) Su zukii type ...... T. paucisu!catus suzukii n. subsp. Genus Trigonioides KoBA YASHJ 3) Paucisulcatus type ...... and Suzt:KJ ...... T. paucisulcatus paucisulcatus 1936. Trigonioides KoBAYASHI and SuzcKI, 4) Il1atsumotoi type ...... T. matsmnotoi japan. four. Ceo!. Geogr., Vol. 13, p. 248. 5) With nodes at intersection of radial 1937. Trigonioides, HOFFET, Bull. du Sen'. giol. and concentric costae .... T. trigonus de /'lndochine, Vol. 24. p. 8. 6) f{odzirai type but lacking them in 1938. 1'rigonioides, MATSt:~JoTo, four. Geol. anterior .... T. lwbayashi ( = T. laotiae) Soc. japan, Vol. 45. p. 15. 7) Extraordinarily developed irregular 1940. Trigonioides, St:ZUKJ, Japan. ]our. Geo/. ribs in posterior .... T. diMrsicostatus Geogr .. Vol. 17, p. 228. 363. Trigonioides and its classification 101 1941. Trigonioides, KoBAYASHI and SuztrKt, oides is more similar to trigonid than Bull. Geol. Inst. Mancl10ullllo. No. 101, to unioid. while Cox referred it to the p. 78. Unionidae, paying attention to the per 1955. Trigonioides, Cox. Cl'o{. Mag.. Vol. 92. sistent hinge in numerous trigonids. p. 348. In agreement with KoB.-\YASIII (1956) the 1956. Trigonioides. KoBAYASHI, Japan. four. Ceo{. Geogr., Yo!. 27. pp. 80-91. writer claims that Trigonioides must be long to the family Trigonioididae by its !\lost distinguishing characteristics of hinge nature. this genus are in the surface ornamenta Hoffetrigonia was erected as a new tion and hinge nature. The surface genus by SuwKr (1940) by the reason is usually marked with V-shaped ribs on that their outline and median tooth in the line across the umbo. Posterior ribs the Laos specimens differ from those of are generally thicker than anterior the japanese and Korean specimens. chevron ribs. An10ng the former there However, KorL-\YASllt (1956) proved Hoffe are extraordinarily stout ones. The or trigonia to be synonymous with Trigon naments in anterior and posterior areas ioides by the reason that they are not are fairly variable among species. The distinct in the outline and hinge nature. hinge teeth consist of regularly crenu I11atsumotoi and paucisu/catus are identi lated pseudocardinal teeth and postero cal with the Laos specimens in the hinge lateral teeth. nature. Therefore KoHAYASIII's opinion Trigo11ioides differs from those of is correct. Trigoniidae and Unionidae in the hinge Trigouioid!!s paucisulcat us nature. In the lack of a bifid mecl ian cardinal in the left valve, this differs St:zuu. 1940. (emend) from Trigoniidae. Supposing that the 1940. Trigonioides kodairai paucisulcatus Sv · lateral tooth of Trigoniidae has been ZUKI, Japan. four. Ceo/. Geogr., Vol. 17, atrophied, however, the dentition of T. p. 229. matsumoloi becomes similar to that of Desaiption :-Shell medium, subtri Scabrotrigonia. On the contrary, Cox gonal. transversely ovate in outline and emphasized that the dentition of Tri subelliptical. Ligament external: pedal gonioides is similar to that of Castalia. scar under strongest tooth (2a or 3a) in However. as KonAYASm pointed out al each valve fairly pronounced. Ornament ready. Castalia has unionid feature in of median area typical of the genus, the irregularity of arrangement and but anterior and posterior ones are inter crenulation. This is also similar to the mediate between kodairai and matsu hinge of Nippononaia. but differs in the motoi. Hinge well developed, characte composition and arrangement of teeth. ristic of the genus: The divergence of pseudocard inal teeth 5a 3a 1 3b in Quadmla and Plagiolopsis seems also (4a)~al'a (l'b) 2b--4b similar to that of Trigo11ioides but the where brackets indicate high variability, former two are entirely different from even the tooth being nullified. 4a low the latter. and weak, lower side only crenulated ; The opinion on the taxonomic position 2a strongest, crenulated on both sides of Trigonioides does not agree between and oblique to hinge margin (ca. 60'): Cox (1955) and KoBAYASHI (1956). KonA· l'b very small below the beak; 2b and Y ASHI stated that the hinge of Trigoni- 4b not protuberant as an independent 102 Yoslzihisa OTA tooth but form a wall of a groove for lar to Nipponmraia ryosekiana St:zuKr in 3b and they are fairly elongated but low. ornamentation but differs from the lat and each crenulated only on one side. ter in the hinge and anterior and post Comparison :-·This species is fairly erior ornaments. T. matsumotoi resem variable in outline and ornamentation. bles this species in the hinge. but they The Wakino specimens are, howe\·er, de disagree in posterior ornament. formed. The ornament of paucisulratus Ocwrrence :-Lower part of upper Wa suzukii is intermediate between kodairai kino formation at Hata. Katsuki-machi, and matsumotoi (Text-fig. 3b). Its orna Yahata-city, Fukuoka Pref. ment somewhat varies in anterior. The ornament happens to disappear in the B. Gosyonoura group anterior and median area. The Siragi specimens are remarkably effaced. Ori According to MATsu~!OTO (1938), Go ginally Suzt:Kr (1940) described it as a syonoura Island consists mainly of the subspecies (kodairai paucisulcatus), but Gosyonoura group and partly of the the writer considers that it is better llimenoura group. and the Gosyonoura to be distinguished from lwdairai as an is Gyliakian in age. T. matsumotoi is independent. generally found as conjoined valves and they are irregularly disposed in the fossil bed (ca. 0.5 m thickness) of the Trigonioides paucisulcatus suzukii coarse sandstone. This occurrence is 0TA, new subspecies negative for long transportation. This fossil bed contains no marine fossil but Plate 11, Figures 12-20. Viviparus (?) sp. is rarely found in it. Description :-Shell medium in size, subtrigonal or subelliptical in outline: Trigonioides matsumotoi KoBAYASHI ribs 3 or 5 in number in umbonal and and SczuKJ, 1940 median area, forming fine elongated Vs pointed ventrally. Ribs about 18 in an Plate 10. Figures. 1-15. terior area, in reversed \'s appear from 1938. Trigonioides kobayashii MATSDIOTO, umbo: their angle more than twice (120" four. Geol. Soc. Japan, Vol. 45, p. 14. Pl. -130°) as large as posterior ones lea. 2. fig. 2. 60'): anterior ribs generally narrower 19:10. Trigonioides matsumotoi KonA YASIII and than posterior ones: posterior ornaments SIJZUKI, Bull. Geol. Ins/. illauclloulmo. vary fairly extensively, but generally No. 101. p. 78. consist of about 11 reversed V -ribs. Descriptio11 :-Shell medium. ovately Observation :-Reversed Vs tend to be subelliptical, regularly rounded in lateral come obsolete from median to anterior margins. Surface marked by radial ribs, margin, while concentric costae appear every two of which meet together, form strong as they procede to ventral margin ing an acute V on the line through or the reversed V-ribs have a tendency umbo: a set of simple ribs composed of to become more or less zig-zag ribs in about 8 on anterior and 3 on posterior; anterior. Another set of irregular ribs another set of ribs branching off toward in posterior are sometimes branching antero- and postero-dorsal margins from toward ventral margin. obtuse umbonal ridge: some of them Comparison:-This subspecies is simi- yielding a few regular Vs in adult stage. 363. Trigonioides and its classification ] 03 Hinge teeth well developed: 228. Pl. 24. Figs. 1 -4. (5a) 3a la (lb) 3b Description :-Shell medium, transver (4a) 2a l'a (l'b) 2b 4b sely ovate and subelliptical in outline. where brackets indicate high variability. Beak submedian. fairly large. prosogy 4a along hinge margin degenerating: rous, more or less incurved. Hinge some fairly strong and crenulated on teeth characteristic of the genus. Sur· both sides. but most of them are weak face with suzukii type of ornament in or undeveloped. 2a strongest. crenulat umbonal and posterior areas. which dis ed on both sides. and oblique to hinge appears in anterior and median areas: margin (ca. 30'). l'a next strongest. concentric costae strong near ventral crenulated on both sides. and oblique to margin. hinge margin (ca. 60°): l'b fairly deve Comparison:-This differs from kodai· loped or undeveloped : even when deve mi. paucisulcatus suzukii and matsumotoi loped. it is small. crenulated on both in ornamentation. The ornament is ef sides. and half as long as 2a: when not faced in various degrees. so much developed. it has small node Occurrence :-Rarely occurs with ma like denticles in two rows: 2b and 4b /sumotoi in upper Gosyonoura group at rather degenerating, small and crenulat Kyodomari, Gosyonoura Island. Kuma ed only on one side. even \Vhen deve moto Pref. loped. VI Phylogeny ,Heasurement: Length Height The development of the hinge and Gu. K 1500 44 rnrn 38 mrn ornaments is brought together with 1502 34 31 .. .. stratigraphical evidence into considera 1501 38 38 .. tion . 1516 42 .. 34 .. 1503 19 19 .. .. A) Hinge nature 1504 22 .. 17 .. The hinge of Trigonioiades is fairly Comparison:-This species is similar constant. although there are some varia to paucisulcatus suzu!?ii but differs in tions in the median and lateral teeth. anterior and posterior ornaments. It re Generally, the lateral teeth indicate the sembles Nippono11aia asinaria REESIDE degenerative features. (1957) in the ornament. but they can be 1) On the variation of the hinge distinguished by the hinge nature. teeth of the right valve. Occurrence :-Upper Gosyonoura group a) In suzuldi. lb is not yet developed at Kyoclomari. Gosyonoura Island. Ku but the median tooth is simple. mamoto Pref. b) In ma/sumotoi. 1b indicates the pri mitive feature of development. Namely, Trigonioides paucisulcatus among the specimens, lb is un-develop paucisulcatus SuzwKI, 1940 ed or a small independent tooth. c) lb is more developed in the Laos Plate 10. Figure 16. specimens than in matsumotoi. but it 1940. Trigonioides kodairai paucisulcatus SvzL· · seems to have some yariation in HoFFET's Kl, Japan. four. Geo!. Geogr., Vol. 17. p. figures. 5a is a fairly constant tooth 104 Yoshihisa OTA but its development is fairly variable. kodairai type, c) matsumotoi type, and 3a and la are constant teeth. b) suzukii type which is intermediate (2) On the variation of the hinge between the two others. When one takes teeth of the left valve. note on ontogeny, each type is a con a) In suzukii, l'b becomes an indepen tinuous series by the intermediate form. dent tooth. Namely, all suzukii speci Paucisulcatus paucisulcatus is specialized mens have it as a tooth but its develop from suzukii type. The upper Naktong ment is fairly variable. subspeciesindicaets an intermediate form b) l'b of matsumotoi and Laos speci between paucisulcatus suzukii and pauci mens is same as that of suzukii but sulcatus paucisulcatus. Its ornament dis the development is fairly variable. appears from anterior to median in c) 4a is rather degenerating. Namely, various degrees. Some specimens of <1a of suzukii appears as a small tooth matsumotoi type indicate also a similar along the hinge margin, but in the Laos feature to kodairai type even in the specimens, 4a is undeveloped and two adult stage. As already illustrated, the rows of small holes are seen on the Laos specimens indicate the ornament hinge plate. 2b and 4b tend to degen of the last stage which is fairly differ erate. 2a and l'a are constant teeth. ent from the above three types (a, b and c). However, their umbonal orna B) Ornamentation ment is rather similar to kodairai type. The above facts on phylogeny may be As illustrated already, the ornaments explained in the manner as shown in of Trigonioides can be divided into a) the table (p. 60). Table 5howing the phylogeny of the Trigonioides. Eo-Cretaceous Neo-Cretaceous ,. Early Middle Late Early Late ~ Low. 0 Up.Noktong Low.Siragi Up. Laos* Trfgonlol ~ Noktong Up.Wakino Gosyonoura kodalrai •·. paUCISUI~(!fUS ·.. SUZU f1 --- c.au~frtca]usauc sulcatus ·. -- matsumotoi ...... ~ kobayashi ·.·.·.. . trigon us ... . divers icostatu s ·. * Terrain rouge cretace de Muong-Phalanc. 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)~ ~~=~l~"t7.>11661JlrFfflllmO.:> t Cl)li. ornament. outline. hinge !'!j\! Nippononoia l:.i]:)'t"P 7.>. fl\ [., hinge, ornament L'ffi:% t,;};, I) Nippmtonaia 0.:> diagnosis c ~~rc:.:;t-3& [.,t.; •. '· Nippo11011aia In 1941, SuzuKI erected a subgenus, at Shinshu, Korea. The specimen (Cox, Nippononaia. with an internal and exter 1955. Text fig. A; KoBA Y;\SHI. 1956. Pl. nal mou Ids. However, whether the V. Fig. 3; 0-rA. Pl. 6, Fig. 11) which specimens came from the Lower Cre was disputed by Cox and KoBAYASHI taceous of Sanchu graben in Kwanto was an internal mould collected by me mountains or Katsuraga,va basin in from the lower w·akino formation. Cox eastern Shikoku was a quesion. They referred it to T. kodairai. and KoBAYASHI were unfortunately gone by a fire in to Plicatozmio naktongensis multiplicatus, the Second Great War. if not a Nippononaia. It is difficult to Lately I collected several specimens decide whether the specimen belongs to from the Lo\ver Cretaceous Wakino sub '' Nippononaia" or Plicatozmio, for its group. They are similar to Trigonioides surface ornament can not be seen. I kodaimi KoBAYASHI and SuzuKI in the have once identified it with T. lwdairai, ornament and Plicatounio kwamnonensis but now it is ascertained that the Wa 0TA in the hinge nature. Namely, they kino specimens can be distinguished have intermediate features between from Trigonioides in the hinge nature. Trigonioides and Plicatowzio but probably I want to describe here two new spe more related to Nippononaia ryoseleiana cies from the lower \Vakino formation, Suz~;Kr in both respects. When the which are provisionally referred to hinge is unknown, one can not dis ·· Nippononaia ", although much obscuri tinguish them from T. kodaimi. There ty is attached to the hinge nature of fore these Wakino specimens have once true Nippono11aia and its taxonomic posi been taken for T kodairai but its type tion is ambiguous. locality is the lower Naktong formation Before going further. I wish to ------* Received July 26, 1958; red Feb. J.!. 1959 record his warmest appreciations to at Hiroshima University. Prof. T. KoBAYASHI of the University 105 lOt) Yoshiltisa OT;l of Tokyo, for his continuous encour valve of " Nippononaia ''. while in that agement, and express many thanks to_ of Trigonioides they are four in number, Messrs I. 1-l.-\YA~II and A. ToKt:YA~IA diverging from beak to the anterior of the l:nh·ersity and l\Tr. 1\1. NAKA:'\o hinge margin with angles of 0 ', 30•. 60° of the Hiroshima University and Assist. and go• (Text-fig. A). Prof. H. Ho:-;To of the Fukuoka Liberal The hinge plate of "Nippononaia" is Arts College at Tagawa for their kind narrow \vith slender teeth and that of help. Trigonioides wide with stout dentition. Suzt:Kr in his second paper (19,13) took I Distinction among "Nippononaia", 1rue Nippononaia as a subgenus of Trigonioides and Plicatounio. Plicatouuio instead of Unio because of its hinge nature indistinguishable from A. The difference of ·• NiPJ>o· that of Plicatounio. .. Nippononaia" is 11011aia" from Trigonioides on one side, somewhat similar toP. lm•mtmonensis 0TA from Plicatounio on the other. One can 0958) in the hinge hut fairly different easily distinguish the last from the from P. nal?tongensis which has many two others in outline and ornament. unionid features in the hinge nature. Namely. Plicafonnio is distinct from them in its posterior radial plications and transversely elongated outline. Pli· II Comparison between American catounio is more or less similar to "Nip species of Nippnno1wi a and pononaia '' in the subquadrate or sub "1Vippononaia ,, of the triangular outline. Wal 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 made from a natural mould.) 2. Trigonioides paucisulcatus suzukii OTA n. subsp. Upper Wakino subgroup, :\. Kyusyu, Japan (based on an artitit:ial wst made fromea 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 made from 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. III Description of Species. As the difference between REE:51DE's form and Wakino one is distinct, I Genus ·• Nippononaia" SuzuKI, 1941 consider at present that the former "Nippononaia" u.:akinoensis 0TA, should be excluded from "NiPPononaia" in my mind. ne\"v species Plate 11, Figures 1-7. 11. 108 Yoshihisa 0Til Description:-Shell medium in size, only on one side. It is a tendency for transversely elongated, subelliptical in 3a or ~a to branch off near beak. The outline. subequilateral, regularly round branching tooth can be seen as arrange ed in anterior and subquadrate in pos ments of nodes under the beak. terior: dorsal margin broadly arched. The ornament of the anterior area is subparallel to ventral margin which is variable. Namely, anterior ribs become slightly curved. Test fairly thick. Beak weak in adult stages, while radial ones fairly prominent, prosogyrous. more or are sometimes replaced by concentric less incurved, placed at about two-fifths costae. In the anterior area ribs are to submedian and fairly projected above sometimes zig-zag or irregular. hinge line. Surface ornamented with Comparison:-This is most similar to many V-shaped ribs crossed by concent N. ryosekiana SuzuKI in outline, orna ric growth lines: radial ribs fine and mentation and hinge nature.* However. closely set in middle: several middle "N." tcaki11oensis differs from N. ribs (6-8) converging to form acute Vs 1·yosekiana in lateral teeth and posterior on a line through beak: each side of ornament. This new species is also them regularly ornamented with rever simi Jar to Trigonioides kodairai and T. sed V-ribs: anterior ribs about 18-20 paucisulcatus suzukii, but differs in the including middle V-ribs smaller and hinge nature. As already discussed, more numerous than posterior !14-16). this differs from N. asinaria REEsJDE in Hinge well developed; cardinal teeth hinge and ornament. relatively short, narrow and finely cre Occurrence :-Lower Wakino formation nulated: lower one stronger than upper: at Rikimaru, l\liyata-machi. Kurate-gun, lateral teeth fairly long, lamellar, finely Fukuoka Pref. crenulated, but weak and Io·wer than anterior ones. Internally, ventral mar "Nippononaia .. sengokuensis 0TA, gin crenulated especially in posterior new species half. Plate II. Figures 8-10. llfeasureml'lz/ s: Height Description :-Shell rather small, ob ----- WJ.S 5057 26mm oval, moderately convex. subequilateral, 506(1 48 31 rather regularly rounded on both sides, 5051 47- 24 ventral margin rounded. Beak small, 5086 42 20 submedian, prosogyrous. more or less incurved. Numerous ribs arranged as usual in tcakinoensis. Hinge teeth Occurrena :-Lower Sengoku format ion identical with those of the species, but in Wakino subgroup at Rikimaru, J:vliyata the angle of hinge margin is smaller. machi, Kurate-gun, Fukuoka Pref. Observation:-The hinge nature and * I showed these specimens of "N." waki surface ornament vary considerably: tzoensis to Dr. K. SuzuKI who erected 1Vippono· naia. He said that the Wakino specimens 4a, 3b and median tooth are developed arc so similar toN. ryosekiana in all respects in some but not in others. Namely, 4a that they arc referable to his subgenus, not and 3b are degenerative. Even when withstanding the fact that the two species developed, they are smaller than the disagree in the number and crcnulation of others and a little convex and crenulated lateral teeth. 364. .. Nipprmonaia" from the Lou.Jer Cretaceous 109 marine Shells of the Naktong-\Yakino Se J11easuremenls: I Length Height ries. Japan. four. Ceol. Ceogr., Vol. 13. --· ------\VI. S 5053 19 mm 17 mm -- and -- (19H). On the Occurrence of Trigonioides in Southeastern .Manchoukuo. 5050 22 21 Bull. Ceol. Ins!. ilfandwukuo. No. 10 I. 5031 18 17 KoBAYASlll. T. (195·1), Studies on the Jura ssic Trigonian in Japan. Pt. 1. Preliminary Comparison:-This is distinguished Notes. Japan. four. Geol. Geo~:r .. Vol. 25. from ''N." zmkinoensis and "N." ryosekiana Nos. 1-2. Suzt:KI by small size and oboval outline -- and MoRJ. K. (1955). The Vaugoniinae of the shell. T. kodairai was originally from the Kitakami 1\lountains in North described from lower Naktong and Japan. On the Jurassic Trigonians in japan. Pt. 3. Ibid .. Vol. 26, Nos. 1-2. 'Vakino series by KoBAYJ\SIII and Suzt;KJ. KonAYASJJI, T. (1956). On the Dentition of The Wakino specimen (KoBAYASHI and Trigo11ioides and its Relation to Similar St:zn:J, 1936. PI. 29. Fig. 13) which they Pelecypod Genera. Ibid .. Vol. 27, No. I. described is incomplete in ornament. LEnKCCJJ:'IER, R. (1932). Die Trigonien des and its hinge nature is also not distinct. Suddel'ltschen Jura. Palaeotogr., Bd. 77. Therefore I cannot accurately determine Mt\TSt::I.JOTo. T. (1938). Geology of the Go whether it is T lwdairai or '' N." sen syonoura Islands. Amakusa, with special gokuensis. But I presume that it is Reference to the Cretaceous Stratigraphy. probably "N.'' sengolme11sis as suggested four. Ceo!. Soc. ]apa11, Vol. 45. by its oboval outline and small size. -- et al. (1954). The Cretaceous System in Occurrence :-Same as the preceding the Japanese Islands. ]apa11. Soc. Promo liou. Sci. Research. Tollyo. species. PH ASH AD. B. (1919). Studies on the Anatomy of Indian 1\Iollusca. No.3. Records bzdimz Heferenccs J"!us .. Vol. 16. REESIDE, J. B. (1957). Non·marine pelecypod Cox. L. R. (1954). ~otes on the Trigoniidae, (Nippo11onaia asinaria) from the Lower with Outlines of a Classification of the Cretaceous of Colorado. Jour. Pal .. Vol. Family. Proc. 11Iat. Soc. London, vol. 29, 31. No.3. Pts. 2 & 3. SL'ZtJKJ. K. (19·10). !\on-marine .Molluscan Fau -- (1955). On the Affinity of Tri;.;mzioides nule of the Siragi Series in South Tyosen. and Hoffetrigonia. Geo/. Mag .. I•'o{. 92. fapau. four. Geol. Ceogr., Vol. 11. Co;-.;RA!J, A. (1853). s~-nopsis of the Family -- (1941), A new naiad, Unio (Nipponouaia) Naiades. Proc. Acad. Nat. Sci. Philadelphia. ryosel~iana, n. subgen. and n. sp. from the Vol. 6. Lower Cretaceous of Japan. four. Ceo/. DAVIES. A.M. (1953). Tertiary Faunas. vo!. Soc. Japan. Vol. 48. 1, London. -- (1943). Restudy on the ~On·IVIarinc Mol HOFFET, J. H. (1937a). Sur le Genre Trigoni· luscan Fauna of the Rakuto Series in oides, l\Iutation genetique stable du Gen Keisho-do. Korea. ] our. Slligen Ka!!aku re Trigonia. C. R. des seances de t.4cad. Kenkyu·Sho. Vol. 1, No. 2. des Sci. Paris, 1937. -- (1949), Dcvelopement of the Fossil Non -- (193ib). Les Lamellibranchis saumatres l\Iarinc lVIolluscan Faunas in Eastern Asia. du Muong Phalane (Bas Laos). Bull. SertJ. fa/J(ln. ]our. Ceo/. GeoJ:/'., Vol. 21. Ceo/. /'llldochine, Vol. 24. THIELE. J. (1934-35). Handbuch der system KOBAY,\SHJ. T and Sezn:J. K. (1936), .!'\on· atischen 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 radial ribs. "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!PACTA SUMIO SAKAGAlVII Department of Geology. Hokkaido Gakugei University and TOSHIKAZU OMA TA l\'lizuho Middle School. Tokyo Prof. Dr. H. E. THAU.IA['.;:'-l has kindly gerina compacta (WHITE, 1932) according called attention to two homonyms in our to DmmAR and SEI:'>il'ER, 1937, Univ. paper (S. SAKAGAMI and T. 0:-.L'\TA, 1957, Texas Bull. 3701, p. 645 (for Triticites Japan., ]our. Geol. Geogr .. val. XXVIII, no. compactus vVniTE, 19:~2). Therefore, new 4. pp. 247-264. pis. XIX-XX). Namely, 1) names Triticites tha!mamzi SAK.\G,nll and our new species Triticites intermedia on p. o~. A TA and Schwagerina guembeli omens is 253 is preoccupied by Triticites jigu!ensis SAKAGA~II and o~IATA are here proposed RAt:SER, 1938, var. intermedia SLYKOWA, for the homonyms T. intermedia SAKA 1948: and again by T. (Jigulites) inter GA:>.II and 0~1ATA and S. guembefi COm medius RozovsKAJA, 1950: from the up pacta SAI:AGAMI and 0MATA, respectively. per Carboniferous of USSR. and 2) our Our thanks arc extended to Prof. Dr. Sclu.mgerina guembeli compacta n. subsp. Hans E. TIL-\DIA:'-i"' of Stanford Univer on p. 258 is also preoccupied by Schwa- sity for having pointed out this error. 111 112 NEWS @ XXI Session. International Geological Congress c fii)II,H:.fmflli ~.h 7.:, International Paleonto- logical Union O)~ft'Ct:t.(kO) r ~/' .?i.:."?\..•"CiliiMiifl~.fif.d?.h7.:,.::.cl::ts:~t..:" A. Paleoecology: l'dethods and principles: examples of paleoecological syntheses. B. Paleobotany: Calcareous algae, especially the Solenoporaceae. Stromatoliths. C. Micropaleontology: ~icsozoic and Cainozoic pelagic Formaminifera and their strati graphical 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..:~·, @ 1959 ~ 8 !1 30 13 .J: I) 9 fl 12 B l.:.;bt..: I) New York -c: IJIH!li ~Jt o International Oceangraphic Congress -c 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.:, {,) Panel I. (9 Sept.) Basis of paleobiogeography (KstAZKlEwtcz. discussion leader) * William S. von ARx-An experimental approach to paleooceanography (a talk will be presented 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 ocean level H. W. lME:- 1959 if 10 fj 18 13 1959 ~ 9 .FJ 25 8 1 9 5 9 ~ 6 Jj 10 f:l Jf!Ji( * '!Flll! ~ fl!H&J{ $!X~ 1*1 1 9 5 9 iF- 6 J'j 15 f:l f:l;;$:15'1=..¥J~~ ~ ~ ~ ~ ..;J-1• ~ 8 *~'1:.!11J.Jf!t:~ * {t;.• it!'$= ~ fi ;fj m Jll ~ m (~ '~'# r.J 1!1! Jj( 8 4 7 8 0 ~) WI 1m ~3.t~ * FiJ liill ~ :!R:iR:imf!EIKzillllT Ell 2 50 f9 ~it g,lf: "71t.- F'M: 'i\ m 5[; r---- , I I (1959 iF 12 fl 6 B iJZlE) L ~f{~1.,t}E 1. IJP.mris :;t;:i!i~~!¥~ 3. J.li{fj;jO)f*Jfl:;r-:f*Jfj l:l:~~<: 'iiH?HHl. ~ O)ftti;lKJ: IJ ~'i'i!T;;, 0 4. ~*~fi!t:;r-t*Jf.ll.\llf{.li.a_,~f*ffl s. ~IEiimJlfi~~