lSSj\) UU31 -ULU4

Transactions and Proceedings

of the Palaeontological Society of Japan

New Series No. 116

Palaeontological Society of Japan December 30, 1979 Co-Editors I taru HAY AMI and Tsunemasa SAITO Associate editor Tomowo OZAWA

Officers for 1979-1980

President: Tetsuro HANAI Councillors: Kazuo ASAMA, Kiyotaka CHINZEI, Takashi HAMADA, Tetsuro HANAI, Itaru HAYAMI, Hisayoshi IGO, Kametoshi KANMERA, Tamio KOTAKA, Ta­ tsuro MATSUMOTO, Ikuwo OBATA, Tsunemasa SAITO, Tsugio SHUTO, Yokichi TAKAYANAGI, Toshimasa TANAI, Ryuzo TORIYAMA Members of Standing Committee: Kazuo ASAMA (Finance), Kiyotaka CHINZE I (General Affairs), Takashi HAMADA (Planning), Itaru HAY AMI (Transactions), Hisayoshi IGO (Foreign Affairs), Ikuwo OBATA (Membership), Tsunemasa SAITO (Transactions), Tsugio SHUTO (Special Papers), Yokichi TAKA YANAGI ("Fossils") Secretaries: Hiromichi HIRA NO and Yasumitsu KANIE (Membership), Kunihiro ISH I­ ZAKI ("Fossils"), Tomowo OZAWA (Transactions), Toshiyuki YAMAGUCHI (General Affairs), juichi YANAGIDA and Ienori FUJIYAMA (Special Papers) Auditor: Sumio SAKAGAMI

The fossil on the cover is Nipponitella explicata HANZAWA, an aberrant uncoiled fusulinacean from the Lower Permian Sakamotozawa Formation, southern Kitakami, Northeast japan.

All communications relating to this journal should be addressed to the PALAEONTOLOGICAL SOCIETY OF JAPAN, c/o Business Center for Academic Societies, Yayoi 2-4-16, Bunkyo-ku, Tokyo 113, Japan. Sole agent: University of Tokyo Press, Hongo 7-3-1, Tokyo, japan. Trans. Proc. Palaeont. Soc. japan, N. S., No. 116, pp. 175-178, pI. 24, December 30, 1979

708. KIDOA, EINE NEUE DIATOMEEN-GATTUNG AUS DEN OBERNEOGENEN KOITOI SCHICHTEN, TENPOKU, HOKKAIDO*

SEIICHI KOMURA

japan Petroleum Exploration Co., Ltd. (JAPEX), Chiyoda-ku, Tokyo 100

Abstract. Kidoa graviarmata, n. gen., n. sp. (araphid diatom) is described from the Koitoi Formation (Upper Neogene) in the Tenpoku district, japan.

Systematische Beschreibung Einleitung Ordnung Pennales SCHUTT, 1896 Bei der Untersuchung der marinen Mikrofossilien aus den neogenen Ablager­ Familie Fragilariaceae ungen, die im Nordtenpoku Gebiet SCHUTT, 1896 umfangreich verbreitet sind, im Zusam­ menhang mit der Suche von Erdol und Gattung Kidoa, n. gen. -gas hat der Verfasser eine neue bogen­ Namengebung: Herrn Hideo Kmo, formige Kieselalge, die von den bereits Direktor von Sakhalin Oil Development bekannten Gattungen vollstandig unter­ Corporation Co., Ltd. in Verehrung ge­ schieden werden kann, neulich gefunden. widmet. In dieser Arbeit beschreibt und illu­ Typusart: Kidoa graviarmata, n. sp. striert der Verfasser die neue Gattung, Diagnose: Theken in Valvarebene mit Kidoa, die zur Familie Fragilariaceae Apikalachse gewolbt, in Gurtelansicht gehOrt. Viele gut erhaltene Exemplare linear-rechteckig, mit den am Pol stehen­ aus den in den Aufbissen gesammelten den derben Fortsatzen, ohne Zwischen­ Materialien wurden fur die Diagnose bander und Septen ; Schalen dorsoventral, und Beschreibung der neuen Gattung mit starker gewolbtem Ruckenrand, und Art verwendet. Alle Exemplare, linear-Ianzettlich im UmriB, unsym­ die in den Praparaten durch Pleurax metrisch zur Apikalebene, mit rand- eingebetteten wurden, werden im Techni­ standige Stacheln und regelmaBig schen Institut von JAPEX aufbewahrt. geordneten transapikalen Streifen ; Apikalarea vorhanden aber Zentralarea fehlend. Bemerkungen: Die bilaterale Struktur­ anordnung und das Fehlen des Raphen­ * Received May 26, 1978; revised manuscript systems rechtfertigen die Gehorigkeit received Sept. 11, 1979; read june 18, 1977 dieser neuen Gattung zur Familie at Shizuoka. Fragilariaceae. Diese Gattung besitzt 175 176 Seiichi KOMURA

derselben Weise wie die Arten von 142'0 Campylosira GRUNOW (vgl. HUSTEDT, 1927-64, S. 128) Cymatosira GRUNOW (vgI. HUSTEDT, op. cit., S. 123) durch Bildung der bandformig geschlossenen Kolonien leben mu.Bte.

Kidoa graviarmata, n. sp.

Tafel 24, Fig. 1-8; Abb. 2, Fig. 1-6

TENPOKU-GEBIET Namengebung: gravis (lateinisch, adv.) =wichtig+armo (lat.)=bewaffnen, nach den durch viererlei Strukturelementen ganz ausgeriisteten Theken. Holotypus: Praparat Nr. JAPEX Fo- 4S'N --\---}~--t----- 11(34)= 14.1 X 78.5(Fm15636, 15635, 15634), Taf. 24, Fig. 1, Abb. 2, Fig. l. Paratypen: Praparat Nr. JAPEX Fo- 11(31)= 18.3 X 90.3(Fm15630, 15631), Taf. 24, Fig. 2, Abb. 2, Fig. 2; Praparat Nr. JAPEX Fo-11 (23) = 19.0 X 90.2 (Fm 15645, 15644), Taf. 24, Fig. 3, Abb. 2, Fig. 6; Praparat Nr. JAPE X Fo-11(25)=13.2X89.8(Fm15642, 15640), Taf. 24, Fig. 4; Praparat Nr. JAPEX Fo-11(14)=8.6x86.0 (Fm 15628), Taf. 24, Fig. 5; Praparat Nr. JAPEX Fo-11(34)=7.2x92.9(Fm15633,15632), Taf. a 10 lorn !===~[=~[ 24, Fig. 6; Praparat Nr. JAPEX Fo-11(40) =9.1x83.0(Fm15626), Taf. 24, Fig. 7, Abb. Abb. 1. Lage des Fundpunktes 2, Fig. 3; Praparat Nr. JAPEX Fo-11(70) =5.3x 132.0 (Fm 16958), Abb.2, Fig. 4; Praparat Nr. JAPEX Fo-11(68)=1l.0x vier folgende Eigentiimlichkeiten: 1) 138.3(Fm16988), Abb. 2, Fig. 5. derbe Fortsatze am Pol, 2) dichtstehende Material: 10 Exemplare. Stacheln am Rande, 3) krammerformiger Typusfundort: Fo-11, Bodenaufschlu.B Schalenumri.B und 4) kurze Streifen auf (Abb. 1), etwa 3,8 km siidostlich von der Oberfiache. Sie besteht im wesentlich Toyotomi (Breitengrad 45'5'14/1N, Lan­ in nachster Verwandtschaft mit der gengrad 141'19'17/10). Gattung Campylosira, die drei erstere Typusschichten: Aschenreicher Kiesel­ Charakteristiken besitzt und sich von gur der Koitoi-Schichten, Oberstmiozan ihr durch die regelma.Big punktierte (vgl. MINATO et aI., 1956; NAGAO, 1960). Ornamente unterscheidet. Beschreibung: Theken in Giirtelansicht Aus Analogie mit den ahnlichen eng-linear, mit gro.Ben derben pedalahn­ Genera mit Fortsatzen und Stacheln la.Bt lichen an den Polen stehenden Fort­ sich vermuten, da.B die lebende Zelle in satzen, die in der schragen Valvarlage 708. Kidoa, eine neue Diatomeen-Gattung 177

daher etwas konvergent, tiber die ganze Oberflache auBer dem hyaIinen Apikalfeld verbreitet, von Pseudoraphe unterbrochen, 8-9 in 10 f1-; Axialarea oder Pseudoraphe sehr eng, fadenahnIich jedoch deutIich, in der MitteIIinie verIaufend. Bemerkungen : Die vorIiegende Art zeigt eine bedeutende RegelmaBigkeit und Einheitlichkeit in der Anordnung der Streifen und StacheIn, wie die mikro­ photographischen Aufnahmen (Taf. 24, Fig. 5 und 7) deutlich zeigen. Sie tritt selten oder zwar meistens als Bruchstiick

DO. in den Tenpoku-MateriaIien auf, aber

0'"0<0 om sie kann durch ihre bogenfOrmigen ~~ om SchaIen mit den unnachahmIichen om DO StacheIn leicht aufgefunden werden. f Do Do Do DO DO DO o Danksagung

2 3 4b 5 6 Der Verfasser ist Herrn Dr. Y. IKEBE, Abb. 2. Kidoa graviarmata, n. sp. Vizeprasident von JAPEX, fUr seine Erlaubnis dieser Ver6ffentIichung und Herrn F. AKIBA von JAPEX fUr seine fruchtbare Diskussionen zu groBem best sichtbar sind und in der Giirtellage Dank verpflichtet. als ungebuckelte Schragflache erscheinen (Taf. 24, Fig. 7 u. Abb. 2, Fig. 4b); Schalen verlangert, eng-linear bis linear­ Literatur Ianzettlich, dorsoventral, gegen den GLESER, S.1. et al. (1974): Diatomovye vodo­ PoIenden allmahlich verschmaIert, flach rosli SSSR, Bd. 1. 1-4, 5-400, 401-404, in AxiaIrichtung doch im Querschnitt Abb. 1-16, Taf. 1-20, 1-93. NAUKA, etwas gew6Ibt, mit stumpf bis scharf Leningrad. gerundeten, nicht geschnabeIten, doch HUSTEDT, F. (1927-64): Die Kieselalgen seIten etwas kopfig geschwollenen Apika­ Deutschlands, Osterreichs und der Schweiz Ienden und auch mit geraden oder wenig mit Beriicksichtigung der iibrigen Lander konkavem Bauchrand und starker, vor Europas sowie der angrenzenden Meeres­ den Polenden pI6tzlich noch starker gebiete: in Rabenhorstes Kryptogamen­ konvexem Riicken, 29-69 f1- lang, 4-5 f1- Flora von Deutschland, Osterreichs und breit; marginale Stacheln entIang der Schweiz, 7. (1): 1-920, Abb. 1-542, (2) : 1-736, Abb. 1-1105, (3): 1-556, Abb. SchaIenrand, in der VaIvarIage aIs ob 1-411, Leipzig. Punkt erscheinend, gleichentfernt und KARSTEN, G. (1928): Bacillariophyta (Dia­ dicht liegend, mit transapikalen Streifen tomeae) : in ENGLER, A.u. PRANTL, K., abwechseInd, 8-9 in 10 f1-; Streifen sehr Die natiirlichen Pflanzenfamilien, 2. 105- kurz, punktiert, aus 1-3 Punkten be­ 303, Fig. 93-424, Verlag von Wilhelm stehend, zur Apikalachse senkrecht und Engelmann, Leipzig. 178 Seiichi KOMURA

MINATO, M. et al. (1965): The geologic SHESHUKOVA·PORETZKAJA, V.S. (1967) : Neo· development of the japanese Islands. genovy morskie diatomovye vodorosli i·xxv, 1-442, Taf. 1-30, Abb. 1-26, Tab. Sakhalina i Kamchatki. Izd. LCU, 1-327, 1-25, Tsukijishokan, Tokio. Taf. 1-50, Abb. 1-9, Tab. 1-19. NAGAO, S. (1960): Explanatory text of the v AN HEURCK, H. (IS96): A treatise on the geological map of japan, Toyotomi. Ceol. Diatomaceae. (iibergesetzt von W.E. Surv. Hokkaido, 1-42, Photo. 1-20, Taf. Baxter). i·xx, 1-55S, Taf. 1-35, Abb. 1- 1-6, 1 Karte. 291. Wisley 'and Son, London.

::It$~;R::ItJ:=OO~~==*f6r~'}f/gElt~~. Kidoa: ;: Q)~.I'l.l:j:>r,,'* • ~l!l!; • ~'UM.l: <, r~Q) 4"?Q) fJU!r~~~~tJ:*- ·n'7.>;: c~ ~l1c"t7.> : 9tJ: IJ t;::.t¥1I!l 1....t.:i'&~· jilij~ ~t;::,;67.>~'ItQ)::r 7;fjt~jf§· jilij1l!ljitffiit;::,7U1:."t7.> r IT· m$dlt;::ji[~t;::l!7U"t7.>*tlo JlHIl~Q)tJ: tJ,'"C't'l. Campylosira GRUNOW tJ~J:~Q) ~ t,Q)t'l. Cat>Q) 3,,?Q)~I1~t -:>-n'7.>Q)'"C', m. Kidoa I'l.;: Q).t;::. t -:> C t;rr~'"C';67.>o 1....tJ'1.... Campylosira l'l.i'&JmJ:Q).'i1;~tJ~Jf':J;liJ!Ut;::5J­ ;(P"t 7.> Q)t;::%,t 1.... -C, Kidoa t'l.m$dlQ)jjlij1l!Ut;:::J;IBW~t;::re7U"t 7.> Q)'"C', ;: Q).'i1;'"C'jjIij~I'l.120JIj ~n 7.>0 ;: Q)m.I'l.J:~Q)~~~tJ, i?~ -C, Campylosira Q).t ~ t;::I:j:>'L' /3 t;:::totJ,n7.> RJ~~I'l.tJ: <. !if.li?tJ,t;::3fj;fjt/3t;::, :it(:-:>-C Fragilariaceae t;::.:t<"t7.>;:ct;::.tJ:7.>o ;:nl'l.mtE"i'"C'Q)c ;: ~*~~~'"C', ;R::ItQ)~*'I-I:j:>'"C'I'l.~ < mt;::, ~ < IUIi)t C tJ:-:> -c!±lm"t 7.>0 tJ::to;:Q)~Q)~fij;IH·~'!J :/:fiilll~~~1J (~) iU;r=oo* ~p**=J:(;t;::t,tJ:tro 'J' ;fJ f,!f -

Toyotomi ~&, Tenpoku ;R::It

Erklarungen zur Tafel 24 (Plate 24)

Fig. I-S: Kidoa graviarmata, n. gen., n. sp. Fig.!. Holotypus. Praparat Nr. jAPEX Fo·ll (34) =14.1x7S.5 (Fm 15636,15635,15634). Koitoi· Schichten. Oberstmiozan. a: hohe, b: mittiere, c: tiefe Einstellung. Fig. 2. Paratypus. Praparat Nr. jAPEX Fo-ll (31)=1S.3x90.3 (Fm 15630, 15631). Ebenda. a: hohe, b: tiefe Einstellung. Fig. 3. Paratypus. Praparat Nr. jAPEX Fo-ll (23)=19.0x90.2 (Fm 15645, 15644). Ebenda. a: tiefe, b: hohe EinsteUung. Fig. 4. Paratypus. Praparat Nr. jAPEX Fo-ll (25)=13.2xS9.S (Fm 15642, 15640). Ebenda. a: tiefe, b: hohe Einstellung. Fig. 5. Paratypus. Praparat Nr. jAPEX Fo-ll (14) =S.6xS6.0 (Fm 1562S). Ebenda. Fig. 6. Paratypus. Praparat Nr. jAPEX Fo-ll (34)=7.2x92.9 (Fm 15633, 15632). Ebenda. a: hohe, b: tiefe Einstellung. Fig. 7. Paratypus. Praparat Nr. jAPEX Fo-ll (40)=9.1xS3.0 (FmI5626). Ebenda. Schrage Valvarlage. Fig ..S. Paratypus. Praparat Nr. jAPEX Fo-ll (27) =5.4xS9.6 (Fm 1563S). Ebenda. Schrage Valvarlage. KOMURA: Kidoa, eine neue Diatomeen-Gattung Plate 24

2 a 2 b 7

1 a 1 b 1 c 3a 3b

4a 4b 5 6a 6b 8 Trans. Proc. Palaeont. Soc. japan, N. S., No. 116, pp. 179-222, pis. 25, 26, December 30, 1979

709. A STUDY OF THE "PENNATAE TRIGONIIDS" FROM JAPAN*

MASA YUKI TASHIRO

Department of Geology, Faculty of Science, Kochi University, Kochi 780

Abstract. The present work is a taxonomic revision of the so-called pennatae trigoniids from japan, with an attempt to explain the evolutionary parallelism be­ tween Hf3terotrigonia and Apiotrigonia. 16 species belonging to the pennatae trigoniids are known from various localities of the Upper Cretaceous in japan. They are classified into two genera (Apiotrigonia and Heterotrigonia) and four subgenera (Apiotrigonia s. str., Heterotrigonia s. str., Microtrigonia and Nakanotrigonia nov.). I propose Apiotrigoniinae nov. as a new subfamily of the Trigoniidae on these genera and subgenera together with several other genera and subgenera outside japan, such as Columbitrigonia, ?Quoiecchia, Dampietrigonia nov. and Turkestanella nov. Apiotrigoniinae nov. 'is mainly composed of the Heterotrigonia trunk and the Apiotrigonia trunk which were probably derived from a common ancestor in the Lower Cretaceous. The evolutionary tempo of the Heterotrigonia trunk is more rapid than that of the Apiotrigonia trunk. Microtrigoniais an off-shoot of Apiotrigonia, whereas Nakanotrigonia nov. is that of Heterotrigonia. The apparently directional changes of characters are recognized in both trunks in parallel with each other.

Introduction in Southwest japan. Since UEDA and FURUKAWA (1960) reported the biostrati­ Many species belonging to the so­ graphy of the Himenoura Group, several called "pennatae trigoniids" (pennatae authors, e.g., HATAE (1959, 1960), AMANO group, AGASSIZ, 1841; pennata group, (1960a, 1960b, 1962, 1963), UEDA (1962), LYCETT, 1872-1879; pinnate forms, YAMAMOTO and HAY AMI (1971), TANAKA NEWELL and BOYD, 1975, excluding and TERAOKA (1973), TASHIRO and NODA Iotrigonia and Vaugonia) have been des­ (1973), TASHIRO (1976), and TASHIRO and cribed from various localities of the OTSUKA (1978), restudied the Himenoura Upper Cretaceous in japan by elder Group. As a result the stratigraphic authors. knowledge of the Himenoura Group was A biostratigraphic study of the Cre­ much improved, and consequently the taceous trigonians in japan was com­ stratigraphic ranges of pennatae trigonian prehensively treated by NAKANO (1960). species were also clearly determined. I The stratigraphical positions of pennatae once described the evolutionary change trigonian species which were listed in of characters in the pennatae trigoniids NAKANO (1957, 1960, 1961) are incorrect on the basis of the material from the in certain parts, especially regarding Himenoura Group (TASHIRO, 1972). Sub­ the species from the Himenoura Group sequently more materials have been * Received july 13, 1979; read Oct. 20, 1979 obtained, and my previous work should in Nagoya. be revised and enlarged in the light of

179 180 Masayuki TASHIRO tions, with abbreviated indication by prefix. GK: Department of Geology, Faculty of Science, Kyushu University (Fukuoka 812) KE: Faculty of Education, Kumamoto University (Kumamoto 860) KSG: Department of Geology, Faculty of Science, Kochi University (Kochi 780)

Acknowledgements

Before going further, I wish to express my sincere thanks to Emeritus Professor Tatsuro MATSUMOTO of Kyushu Univ. for his kind encouragements, critical reading of the first draft and supplying me with valuable information and several Text-fig. 1. Map showing the localities specimens from the Upper Cretaceous of of the pennatae trigoniids in Japan. Hokkaido. My sincere gratitude is ex­ °A: Middle Yezo Group; AI. Shimo-katsura­ tended also to Professor Minoru TAMURA zawa, A2. Katsurazawa. B: Mikasa For­ mation (Turonian part) (Pombetsu). C: of Kumamoto Univ., for his valuable Upper Yezo Group; C1. Saku, C2. Urakawa. suggestions and encouragements, to Dr. D: Hakobuchi Group (Tomiuchi = Hetanai). Mitsuo NAKANO and Dr. Itaru HAY AMI, E: Futaba Group; E1. Hirono, E2. Ashi­ for their kind advice. Thanks are due zawa. F: Izumi Group; F1. Izumi Moun­ to Mr. Katsukichi YAMAMOTO, for the tains, F2. Awaji island, F3. Matsuyama, F4. supplying me several pennatae trigonians Yuasa. G: Sotoizumi Group (Kaiisako from the Izumi Group, to Mr. Iwane Formation) (Monobe). H: Uwajima G.·oup MIZUNO, from the Uwajima Group, to (Uwajima). I: Onogawa Group (Inukai). Mr. Masao OTSUKA, from the Himenoura J: Lower Himenoura Subgroup; J1. Uto Group, and to Mr. Makoto OKAMURA Peninsula, J2. Amakusa-Kamishima Island. K: Upper Himenoura Subgroup; K1. eastern from the Upper Yezo Group. My thanks coast of Amakusa-Shimojima Island, K2. are extended to Dr. D. H. POULTON of western coast of Amakusa-Shimojima Island, the Geological Survey of Canada, for K3. Shimo-koshikijima Island. his kind advice and Dr. S. K. SKWARKO of the Bureau of Mineral Resources, up-to-date knowledge. Geology and Geophysics of Australia In this paper I offer revised taxonomic for his kind supply of the Australian classification of the pennatae trigoniids specimens. from Japan, and attempt to discuss the origin and evolution of this group. Revised Classification of the Repository Pennatae Trigoniids The specimens treated in this paper are stored in the following three institu- Systematic Description 709. Pennatae trigoniids from Japan 181 Order Trigonioida which transversely cross the umbonal concentric costae. The subhorizontal Superfamily Trigoniacea costae on the anterior part of the disk Family Trigoniidae LAMARCK, 1819 generally cut across the growth lines from lower to upper. A young shell or Subfamily Apiotrigoniinae nov. umbonal part of some genera of this subfamily resembles Frenguelliella LEAN­ Diagnosis.-Shell usually small, pyri­ ZA, 1942, and Rutitrigonia VAN HOEPEN, form or trigonally ovate; umbo normally 1929, in their surface ornamentation and opisthogyrous, but nearly orthogyrous in their outline of a valve as already a few groups, located more anteriorly mentioned by TASHIRO (1972). Trigonia than the mid-point of the valve length; sydariensis ARCHANGELSKI (1916), from disk ornamented with two sorts of the Cenomanian of Turkestan, is charac­ costae: the concentric or subhorizontal terized by feeble subradial costae on the ones, occupying the umbonal and posterior part and concentric costae on anterior parts of the disk and the subradial the anterior part. NAKANO (1957) sug­ ones, developed usually on the posterior gested that Trigonia sydariensis is half of the disk, but often also on the referable to Rutitrigonia. Rutitrigonia anterior part of the disk; area ornamented efr. laeviscula (LYCETT) (SA VELIEV, 1958), with oblique or radial costellae, or from the Lower Cretaceous of Turkmenia, smooth; escutcheon narrow, ornamented is similar to the species of the Apiotri­ with oblique costellae or smooth; dorsal goniinae in its features of concentric and marginal carinae weak or indistinct costae on the disk. Since the Turkme­ except near the umbo; median groove nian species lacks distinct subradial weak or obscure. costae, numerous short costae appear Remarks.-Some genera, e.g., Apiotri­ under the marginal carina. I think, those gonia and Heterotrigonia, of this new two species may represent intermadiate subfamily resemble Vaugonia CRICKMA Y, forms between the Apiotrigoniinae and 1932, and Iotrigonia VAN HOEPEN, 1929, the group of Rutitrigonia. Many species in having the reverse L-shaped costae of Rutitrigonia, e.g., Trigonia pseudo­ which are formed by two sorts of costae indica ARCHANGELSKI (1916), from the on the disk. Vaugonia, however, differs Cenomanian of Turkestan, T. weaveri from them, in having its distinct STOY AN ow (1949), from the Aptian of marginal and dorsal carinae, and trans­ Texas, Rutitrigonia yeharai KOBAYASHI versely laminated costellae on the area. (1954 ; HAY AMI, 1968) and Rutitrigonia The L-shaped costae of Vaugonia and amagensis KOBAYASHI (1956) from the Iotrigonia were probably originated step Jurassic of Mindoro, are characterized by step from the concentriccos tae. There­ by a pyriform outline and plain sub­ fore, the costae on the anterior part of the horizontal costae which are obscured on disk in Vaugonia and Iotrigonia usually the posterior part. Though they have no cut across the growth lines from upper subradial costae, they resemble the to lower. On the other hand, the species of this subfamily in their features L-shaped costae of the genera belonging of the outline and the ornamentation of to Apiotrigoniinae, appear suddenly at anterior part. VAN HOEPEN (1929) esta­ an early stage of growth, on account of blished the subfamily Rutitrigoniinae the appearance of the subradial costae (Laevitrigoniinae, SA VELIEV, 1958; Fren- 182 Masayuki TASHIRO guelliellinae NAKANO, 1960) based on his Genus Apiotrigonia Cox, 1952 genus Rutitrigonia VAN HOE PEN), 1929 (type-species: Rutitrigonia peregrina VAN Type-species: Trigonia sllicataria HOEPEN). NAKANO (1963) amended Ruti­ LAMARCK, 1819. trigoniinae to which he referred Diagnosis.-Shell medium to small for Frenguelliella, Geratrigonia KOBAYASHI, trigoniids but large to small for the 1954, Latitrigonia KOBAYASHI, 1954, Apiotrigoniinae; umbo more or ·less Ibotrigonia KOBAYASHI, 1954, Laevitri­ prominent, located anteriorly; disk gonia LEBKUCHNER, 1933, Linotrigonia ornamented with two sorts of costae: Cox, 1952, Psilotrigonia Cox, 1952, the concentric or subhorizontal costae, Nipponitrigonia Cox, 1952, and Rutrigonia. generally appear on the umbonal part HAY AMI (1975) listed, however, Frengilel­ and the anterior part of the disk, and liella, Geratrigonia, Latitrigonia, Nipponi­ the subradial ones covering the posterior trigonia, Ibotrigonia and Rutitrigonia, part of the disk but sometimes present as members of the subfamily Trigoniinae on the anterior part of the disk; area LAMARCK, 1819. In my opinion, the smooth or ornamented by oblique or Rutitrigoniinae, the Trigoniinae (KOBA­ concentric costellae; escutcheon de­ YASH!, 1954; NAKANO, 1961) and the pressed, ornamented by oblique or Nototrigoniinae SKW ARKO (1963) are horizontal costellae, or smooth; escut­ closely related to one another, and they cheon carina almost invisible except form a group under the Trigoniidae. near the umbo; marginal carina distinctly Apiotrigoniinae nov. are also added to angulated near the umbo but gradually them as one of the members of this changing into rounded ridge on the group. The Apiotrigoniinaeare most posterior part; median groove weak or closely related to the Rutitrigoniinae, indistinct. but discriminated by its subradial costae Remarks.-The outline of the valve is on the posterior part of the disk. rather constant in each species of this genus. The anterior costae of the disk List of genera and subgenera.­ (anterior series) are variable in number, Genus Apiotrigonia Cox, 1952 strength and appearance in each species. Subgenus Apiotrigonia Cox, 1952 ; The posterior subradial costae (posterior Microtrigonia NAKANO, 1957; Dampie­ series) are, however, rather constant in trigonia nov.; Turkestanella nov. number and strength in each species but Genus Heterotrigonia Cox, 1952 for several species, e.g., Apiotrigonia Subgenus Heterotrigonia Cox, 1952; (Apiotrigonia) obsoleta NAKANO.. A. (A.) Nakanotrigonia nov. crassoradiata NAKANO, A. (? A.) dubia Genus Columbitrigonia POULTON, 1977 nov. and A. (Microtrigonia) imlltensis ?Genus Quoiecchia CRICKMA Y, 1932 (TASHIRO). The costae of the anterior Age and distribution.-Upper Jurassic series are plain, narrower than their and Cretaceous; Western Europe, Tur­ interspaces and regularly spaced on the kestan, Japan, Sakhalin, Kamchatzka, umbonal region. A very narrow marginal Cordillera of North America, southern sulcus is recognizable on a portion closest part of the interior province of North to the umbo in some species, e.g., Apio­ America, Central America, western trigonia (Apiotrigonia) minor (Y ABE and Australia, Patagonia, Chile and South NAGAO), A. (A.) utoensis TASHIRO, A. (A.) Africa. undlliosa NAKANO, A. (A.) obsoleta NAKA- 709. Pennatae trigoniids from Japan 183

NO, A. (? A.) dubia nov., A. (Microtrigonia) and AGUIERA), from the Upper jurassic amanoi (NAKANO), A. (M.) imutensis of Mexico and Texas (CRAGIN, 1905; (T ASHIRO) and A. (Turkestanella) turke­ STOY AN ow, 1949), is the oldest species stanensis (ARCHANGELSKI) (subgen. nov.). belonging to Apiotrigoniinae nov. TASHIRO (1972) has already illustrated SKW ARKO (1970) referred T. calderoni to the umbonal characters of several species Apiotrigonia. NAKANO (1971) crassified of this genus. T. calderoni in Heterotrigonia, because Age and distribution. - Cretaceous; of its radial costellae on the area. I Western Europe, Turkestan, japan, think that T. calderoni was a common Sakhalin, Kamchatzka, Cordillera of ancestor of the species of Apiotrigonia North America, southern part of the s. 1. and Heterotrigonia s. 1. I list here, interior province of North America, Trigonia calderoni as a member of Hete­ western Australia, Patagonia, Chile and rotrigonia s. str., following NAKANO'S South Africa. classification. Cox (1952) and NAKANO (1957) referred many species to Apiotri­ Subgenus Apiotrigonia Cox, 1952 gonia s. 1. The species undoubtedly referable to Apiotrigonia s. str. are as Type-species: Trigonia sulcataria LA­ follows.- MARCK, 1819. Trigonia buchi GEINITZ, 1872; Middle Diagnosis.-Shell large to medium for Cretaceous of Sachsen Apiotrigoniinae, pyriform, longer than T. concardiformis (KRAUSS) in KITCHIN high; umbo weakly prominent, opistho­ (1913); Lower Cretaceous of South gyrous or nearly orthogyrous in a few Africa species; disk ornamented by two series ?T. condoni PACKARD, 1921; Aptian of of costae; anterior ones concentric or British Columbia subhorizontal, very often weakly inclined T. cragini STOY ANOW, 1949; Aptian of or undulated, sometimes vanished, located Texas on an anterior half or more limited Apiotrigonia crassoradiata NAKANO, anterior part of the disk; posterior ones 1957; Campanian of japan subradial, sometimes tuberculated, oc­ A. (? A.) dubia sp. nov.; Maastrichtian cupying about a posterior half of the of japan disk; area rather narrow, ornamented Trigonia heterosculpta STANTON, 1901; with oblique or subhorizontal costellae, Lower Cretaceous of Patagonia sometimes sculptured with concentric Apiotrigonia hetonaiana TASHIRO, 1978 ; costellae; fine concentric plain costellae Maastrichtian of japan regularly spaced on umbonal area in Trigonia kayana ANDERSON, 1938 ; some species; escutcheon narrow, deeply Aptian of California depressed, ornamented by oblique or T. kitchini STOY ANOW, 1949; Aptian of subhorizontal costellae, or smooth on Texas some foreign species; median groove T. maudensis WHITEAVES, 1876; Upper shallow. Cretaceous of British Columbia Remarks.-This subgenus resembles T. subovalis var. minor Y ABE and Heterotrigonia s. str. in the two series NAGAO, 1925; Senonian of Japan and of costae, but differs clearly from the Sachalin latter in its less-developed radial costellae Apiotrigonia (Apiotrigonia) mikasaensis on the area. Trigonia calderoni (CASTILLO sp. nov.; Cenomanian and Turonian 184 Masayuki TASHIRO

of japan and Sachalin and NAGAO) : KOBAYASHI, Japan. Jour. Trigonia newcombei PACKARD, 1921; Ceol. Ceogr., vol. 25, nos. 1-2, p. 77. 'Middle Cretaceous' of British 1957. Apiotrigonia minor (Y ABE and NAGAO) : NAKANO, Japan. Jour. Ceol. Ceogr., Columbia vol. 28, nos. 1-3, p. 110, pI. 8, fig. 4, NAKANO, 1957; Apiotrigonia obsoleta non. figs. 1-3. Santonian and Campanian of japan 1957. Apiotrigonia obliquecostata NAKANO, Trigonia pennata SOWERBY, 1819 ; Japan. Jour. Ceol. Ceogr., vol. 28, nos_ Cenomanian of England 1-3, p. 113, pI. 8, figs. 9-10. Apiotrigonia (Apiotrigonia) progonos 1962. Apiotrigonia minor (Y ABE and NAGAO) : (PAULCKE) in REYES and PEREZ SAITO, Bull. Fac. Arts and Sci. Ibaraki (1978); Neocomian and Aptian of Univ., Nat. Sci., no. 13, p. 63, pI. 1, Chile figs. 8-9. T. pumila NILSON in Hi\GG (1954); 1962. Apiotrigonia ashizawaensis SAITO, Bull. Cenomanian of Germany Fac. Arts and Sci. Ibaraki Ul~iv., Nat. Sci., no. 13, p. 63, pI. 1, fig. 6. T. sulcataria LAMARCK, 1819 (Cox, 1967. Apiotrigonia minor (Y ABE and NAGAO) : 1952); Cenomanian of France MAEDA and KAWABE, Prof. H. SHIBA­ ARCHANGELSKI, 1916; T. turkmenensis TA Mem. Vol., Tokyo, p. 423, pI. 1, figs. Cenomanian of Turkestan 10-25. Apiotrigonia utoensis TASHIRO, 1972; 1967. Apiotrigor..ia futabaensis MAEDA and Lower Campanian of japan KAWABE, Prof. H. SHIBATA Mem. Vol., A. undulosa NAKANO, 1957; Coniacian Tokyo, p. 421, pl. 1, figs. 5-6. of japan 1967. Apiotrigor.ia hironoensis MAEDA and Trigonia condoni PACKARD, 1921 was KAWABE, Prof. H. SHIBATA Mem. Vol., referred to Megatrigonia (Apiotrigonia) Tokyo, p. 422, pI. 1, figs. 7-8. by JONES (1960), but to Columbitrigonia 1967. Apiotrigonia orikiensis MAEDA and by POULTON (1977). KA\VABE, Prof. H. SHIBATA Mem. Vol., Tokyo, p. 423, pI. 1, figs. 1-4. Age and distribution. - Cretaceous; 1972. Apiotrigonia minor (Y ABE and NAGAO) : Western Europe, British Columbia, Texas, T ASHlRO, Trans. Proc. Palaeont. Soc. California, Patagonia, Chile, Turkestan, Japan, N.S., no. 86, text-figs, I-b, 3-c, South Africa, Sachalin and japan. 4 and 6-a, pI. 40, figs. 1-17 (compare, not described). 1975. Apiotrigonia (Apiotrigonia) minor Apiotrigonia (Apiotrigonia) minor (Y ABE and NAGAO): HAY AMI, Univ. (YABE and NAGAO) Mus., Univ. Tokyo, Bull. no. 10, p. 114. 1975. Apiotrigonia (Apiotrigonia) oblique­ Plate 25, Figs. 18-20, Text-fig. 2 costata NAKANO: HAYAMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 115. 1923. Trigonia subovalis lIMBO: YEHARA, Japan. Jour. Ceol. Ceogr., vol. 2, no. 3, Material.-KSG 2050-2052, 2059-2060 p. 78, pI. 11, figs. 4-8. and KE 1904-1910, collected from the 1925. Trigonia subovalis lIMBO var. minor Lower Himenoura Subgroup at Wadano­ Y ABE and NAGAO, Sci. Rept. Tohoku hana of Ryugadake-machi, Amakusa Imp. Univ., ser_ 2,' vol. 7, no. 4, p. 116. Kamishima Island, Kyushu. KSG 2048- 1930. Trigonia subovalis var. minor Y ABE and NAGAO: NAGAO, Jour. Fac. Sci., 2049, from the same subgroup at Hino­ Hokkaido Imp. Univ., ser. 4, vol. 1, no. shima islet of Amakusa Kamishima 1, p. 18. Island; KSG 2053-2054, plaster casts 1954. Apiotrigonia subovalis minor (Y ABE from the Furushiro-yama Formation of 709. Pennatae trigoniids from Japan 185 the Uwajima Group of Furushiro, Hiromi­ strongly depressed, ornamented with machi, Uwajima City, Ehime Pref. KSG subhorizontal or slightly oblique numer­ 2055-2058 are collected from the Lower ous plain costellae; area broad, orna­ part of the Futaba Group of Hirono­ mented with two sorts of plain costellae; machi and Iwaki City, Fukushima Pref. one of them occupying nearly the full Description.-Shell medium in size, surface of the area except near the moderately inflated; test rather thick; siphonal margin, subhorizontal or oblique, anterior margin semi-circular, passing each of which is conjoined with a gradually into broadly arched ventral costella on the escutcheon; the other margin; posterior dorsal margin weakly sort of costellae are concentric or trans­ concave, as long as about a half length verse, generally developed near the of the valve; siphonal margin somewhat marginal carina crossing the other sort broad, well rounded; umbo large but a of costellae; escutcheon carina scarcely little elevated from the dorsal margin, visible only near the umbo; marginal slightly opisthogyrous, located at about carina distinct near the umbo but two-fifths of the length from the front gradually changing posteriorly into of the valve; disk ornamented with two broadly rounded ridge; median groove series of costae; a boundary between the shallow; inner surface smooth; inner anterior series and the posterior series ex­ anterior margin and posterior part of tending nearly straight from a little poster­ the inner ventral margin broadly ior of the umbo to the nearly mid-point crenulated. of the ventral margin; the costae of the anterior series plain, narrower than their Measurements (in mm).- Specimen Length Height Thickness interspaces, 10 or more costae on umbonal KE 1904, region concentric, regularly spaced, next left valve 30.7 22.0 6.4 about 10 costae on the median part of KE 1905, 28.5 19.6 6.5 the series broadly spaced, horizontal or left valve KE 1906, 22.8 concentric in general, but sometimes left valve 17.3 5.5 oblique, the rest costae of the anterior KE 1907, series on the anterior ventral part very right valve 31.1 20.6 7.0 variable in strength, subhorizontal, con­ KE 1910, 20.3 15.7 5.8 centric, oblique, undulated, irregularly right valve KE 1909, 9.0 waved, bended in V shape, or disappear­ left valve 31.0 25.6 ing (see, TASHIRO 1972, p. 329, text-fig. KSG 2053, 4, pI. 40, figs. 1-13) ; the costae of posterior left ex. 15.8 10.5 3.2 mould series strong, broader than their inter­ KSG 2054, spaces, countable between 10 and 13 in right ex. 33.0 24.9 5.6 the adult specimens, the first 6 or so of mould KSG 2055, the series narrow on the upper side but right ex. 24.0 18.0 6.6 soon become sturdy on the lower side, mould not reaching the ventral margin, of KSG 2056, left ex. 24.0 16.5 4.5 which the first one begins to appear on mould a little posterior of umbo, the other costae somewhat narrower than those of the Remarks.-YABE and NAGAO (1925) anterior ones, reaching subradially the established minor as a variety of Trigonia ventral margin; escutcheon broad, subovalis lIMBO, based on many syntypes 186 Masayuki TASHIRO

umbonal concentri c costae ( Frenguelliello-Iike stage)

subconcentric or subhorizontal costa e (anterior s,eries) Text-fig. 2. Illustration and terminology of the costae on the disk of the pennatae trigonian, based on Apiotrigonia (Apiotrigonia) minor (Y ABE and NAGAO), scale 5 mm. from several localities of Hokkaido, arrangement of costae of the anterior North Sachalin, Northeast Japan and series (see, TASHIRO 1972). The variable Southwestern Kyushu, but NAKANO (1957) costae are also shown in the illustrations ranked it up as a distinct species of of the specimens from the Futaba Group Apiotrigonia and designated a specimen by MAEDA and KA WABE (1967). as the lectotype which was collected Occurrence.-Siltstone of the lower from the lower part of the Futaba Group part of the Futaba Group at Oriki of of Northeast Japan (Y ABE, 1927, pI. 7, Hirono-machi, Futaba-gun, and Ashizawa fig. 4). A form represented by the of Yachi, Iwaki City, Fukushima Pre­ specimens from Hokkaido (YEHARA, fecture; Inoceramus uwajimensis Zone; 1915, pI. 1, figs. 14-17) belongs to Apio­ Coniacian; Lower Urakawan. Sandstone trigonia (Apiotrigonia) mikasaensis nov., of the upper part of the Furushiroyama because its foremost costa of the series Formation of the Uwajima Group, at is more numerous than those of this Furushiroyama of Hiromi-machi, Ehime species. The specimens from the lower Prefecrure; Santonian; Urakawan. Black part of the Uwajima Group (pI. 25, figs. siltstone of the Lower Formation of the 9-10), which were collected by Mr. I. Lower Himenoura Subgroup at Hino­ MIZUNO, are small and characterized by shima, Goshonoura island and Futamado more numerous costae of the posterior of Himedo, Amakusa-Kaminoshima area. series than those of this species. They Black siltstone of the Middle Formation are probably immature shells of Apiotri­ of the same subgroup at Wadanohana gonia (Apiotrigonia) undulosa NAKANO, and Kugujima of Takado, Amakusa­ which is characterized by strong costae Kamishima area, Kumamoto Prefecture. of the posterior series and irregular Inoceramus amakusensis and Inoc. japon- 709. Pennatae trigoniids from Japan 187 icus Zones; Santonian; Upper Urakawan. interspaces, the first 5 or so of the same series short, subvertical, not reaching Apiotrigonia (Apiotrigonia) the ventral margin, of which the first one begins to appear under the umbo, mikasaensis sp. nov. the other 12 or so subradial, occupying Plate 25, Figs. 1-6, Text-fig. 3 the posterior half of the disk; escutcheon strongly depressed, narrow but elongated 1915. Trigonia cf. subovalis lIMBO: YEHARA, with about a half length of the valve, Sci. Rept. Tohoku Imp. Univ., ser. 2, ornamented with narrow, plain, sub­ vol. 2, no. 2, p. 42, pI. 1, figs. 14-17. horizontal costellae; area narrow, orna­ 1957. Apiotrigonia minor (Y ABE and NAGAO) : mented with oblique and narrow costellae, NAKANO, Japan. Jour. Geol. Geogr., vol. which are conjoined with the costellae 28, nos. 1-3, p. 110, pI. 8, fig. 1, non. figs. 2 and 3. of the escutcheon near the umbonal or anterior half of the area, but on the Material.-Holotype KSG 2061, is a posterior half of the area the costellae right valve from the Ponbetsu (Loc. IK are obscured and shown only by fine 2016), Mikasa area, Hokkaido ; KSG 2068- growth lines; escutcheon carina obscure; 2070 (paratypes), from the same locality marginal carina distinct near the umbo, as the holotype; GK. H6910-6913 (para­ moderatelyangulated, but soon weakened types), from Ponhorokabetsu, Yubari and changing into rounded ridge on the dome, Hokkaido (Loc. Yb 67r, see MATSU­ posterior part of the valve; median MOTO and HARADA, 1964) (Masato HARA­ groove very weak; inner surface weakly DA colI.) impressed by the subradial ribs of the Description.-Shell medium in size, posterior series. moderately inflated; test rather thin; anterior margin semi-circular, ventral Measurements (in mm).- Specimen Length Height margin broably arched on the anterior Thickness KSG 2068, part but nearly straight on the posterior; right valve 19.0 14.3 3.0 dorsal margin long, weakly concave; KSG 2061, 17.9 14.0 3.3 siphonal margin somewhat narrow but right valve GK.H 6910, well rounded; umbo small, a little pro­ right valve 34.8 22.1 6.5 minent, opisthogyrous, located at about GK.H 6912, a third or a fourth of the length from left valve 33.2 24.5 6.2 the front of the valve; disk with two GK.H 6913, left valve 31.2 20.5 5.0 series of costae; anterior series plain, narrower than their interspaces, 5 or Remarks.-This species is one of the more costae on the umbonal region con­ oldest species of Apiotrigonia s. str. centric, regularly spaced, next 15 or from Japan. The specimens which have more on the median part of the hitherto been called "Trigonia subovalis series subhorizontal but sometimes var. minor YABE and NAGAO" or "Apio­ weakly waved; on the anterior ventral trigonia minor (Y ABE and NAGAO)" from part of the adult specimens, the anter­ the Mikasa Formation and the Middle ior series generally obscured or become Yezo Group in Hokkaido can be mostly irregularly flexous; the costae of the referred to this species. The specific posterior series number 17 or more, name is derived from the Mikasa For­ plain, a little wider than their mation of central Hokkaido, in which 188 Masayuki TASHIRO in its foremost costae which begins to appear under the umbo, but differs in its distinct radial costellae which are one of the important characters in Heterotrigonia s.1., and its less numerous costae of the anterior and posterior series. Occurrence.-Sandstone of the Mikasa Formation of Ponbetsu, (IK 2016), Mikasa City, Hokkaido; Inoceramus hobetsuensis Zone. Sandstone of the Middle Yezo Group at Y onnosawa of Ponhorokabetsu, Text-fig. 3. Apiotrigonia (Apiotrigonia) Yubari (Yb 67r, see, MATSUMOTO and mikasaensis sp. nov., scale 5 mm. HARADA, 1964), Hokkaido. This species is probably restricted to the Upper this species occurs commonly. Gyliakian (Turonian). Apiotrigonia (Apiotrigonia) minor(Y ABE and NAGAO) is discriminated from this Apiotrigonia (Apiotrigonia) species by its less numerous and stronger undulosa NAKANO subradial costae of the posterior series, less numerous and more irregular costae Plate 25, Figs. 7-10, Text-fig. 4 of the anterior series, distinct and 1957. Apiotrigonia undulosa NAKANO, Japan. widely spaced costellae on the area, and Jour. Ceol. Ceogr., vol. 28, nos. 1-3, more posterior location of the foremost p. 112, pI. 8, fig. 8. (i. e. the first) costa of the posterior 1972. Apiotrigonia undulosa NAKANO: T ASH 1- series. Apiotrigonia (Apiotrigonia) undu­ RO, Trans. Proc. Palaeont. Soc. Japan, losa NAKANO is closely similar to this N. S., no. 86, pI. 40, figs. 18-19, text­ species in its numerous costae of the figs. I-a and 2-8 (compare, not des­ posterior series and finely waved costae cribed) . of the anterior series. The foremost 1975. Apiotrigonia (Apiotrigonia) undulosa costa of the posterior series in this NAKANO: HAYAMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 115. species is, however, located more anter­ iorly than that in A. (A.) undulosa Material.-KSG 2071-2072 and KE 1925- NAKANO. Other specimens belonging to 1926, imperfect specimens from Sakura­ Apiotrigonia s. str. in Japan, e. g., Apio­ dani, Hirono-machi, Fukushima Pref.; trigonia (Apiotrigonia) crassoradiata KSG 2073-2074, external moulds collected NAKANO, A. (A.) hetonaiana TASHIRO, from Hiromi-machi, Uwajima City, Ehime A. (A.) utoensis TASHIRO, A. (A.) obsoleta Pref. by Mr. I. MIZUNO; KSG 2062-2067, NAKANO and A. (? A.) dubia sp. nov. are from Kajisako of Otochi, Kami-gun, clearly discriminated from this species in Kochi Pref. their less numerous costae of the anterior Description.-Shell medium in size, and posterior series, and more posterior weakly inflated; anterior margin well locations of the foremost costa of the arched and nearly semi-circular, ventral posterior series. Heterotrigonia (Hetero­ margin long, broadly arched; posterior trigonia) subovalis (JIMBO), radiate form, dorsal margin elongated and weakly (see, p. 210), resembles this species concave; siphonal margin narrow and 709. Pennatae trigoniids from Japan 189 well rounded; umbo small, slightly for near the umbo; posterior half of elevated from the dorsal margin, a little the area nearly smooth except for fine opisthogyrous, located at a fourth of growth lines; escutcheon carina indis­ length from the front of valve; disk tinct; posterior carina angulated near ornamented with two series of costae the umbo but gradually changing into except near the umbo; the costae of the roundly elevated ridge; median groove anterior series, which occupy about a of the area very weak. half of the disk, plain, narrower than their interspaces, densely crowded and Measurements (in mm).- concentric near the umbo, irregularly Specimen Length Heigth Thickness undulated or wavy on the main part, KSG 2072, right ex. 23.0 16.0 and on the antero-ventral part gradually mould obsolete to be represented by growth KSG 2073, lines only; the costae of the posterior left ex. 12.0 11.0 1.8 mould series fairly broader than the anterior KSG 2074, ones, broader than their interspaces left ex. 9.0 7.2 number about 20, of which the first 10 mould KSG 2062, or so do not reach the ventral margin, left valve 19.0 14.2 2.9 and the first short costa begins to appear KSG 2063, 11.1) at a point a little posterior to the umbo; left valve 14.0 about 10 succeeding costae stretch from KSG 2064, left valve 14.0 11.0 the postero-ventral carina to the ventral margin; escutcheon narrow but elong­ Remarks.-Many specimens are col­ ated, ornamented with about 20 or more lected from the Futaba Group of North­ subhorizontal and plain costellae; area east Japan and the Uwajima Group of somewhat broad, ornamented with Shikoku, although some of them are numerous wavy subconcentric costellae imperfect external moulds. The specimens near the umbo, and with numerous (pI. 25, figs. 7-10) from Hiromi-machi of subhorizontal costellae which are con­ Uwajima and Kajisako of Otochi both nected with the costellae of escutcheon in Shikoku, represent the immature stage on the anterior half of the area except of this species. Mature specimens are generally about 40 mm or more in length. This species is characterized by the strongly undulated costae of the anterior series. Such costae generally appear on some species of Apiotrigonia s. str., e. g., A. (A.) minor (Y ABE and NAGAO) and A. (A.) crassoradiata NAKANO. In this species, the undulate costae are some­ what crowded and occupy the majority of the anterior series. This species closely resembles A. (A.) minor, but it has undulated costae in the anterior series and less numerous subradial costae Text-fig. 4. Apiotrigonia (Apiotrigonia) of the posterior series. This species is undulosa NAKANO, scale 5 mm. similar to A. (A.) mikasaensis sp. nov. in 190 Masayuki TASHIRO having numerous costae of the posterior Japan. Jour. Geol. Geogr., vol. 28, nos. series, but differs in the foremost costa 1-3, p. 113, pl. 8, figs. 9 and 10. of the posterior series which appears 1975. Apiotrigonia (Apiotrigonia) crassora· later in that species. It is probably a diata NAKANO: HAYAMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 115. derivative from A. (A.) mikasaensis sp. 1976. Apiotrigonia crassoradiata NAKANO: nov. A. (A.) utoensis TASHIRO resembles TASHIRO, Palaeont. Soc. Japan, SPec. this species in the wavy concentric Pap., no. 19, p. 57, pl. 7, figs. 4-6. costellae near the umbo on the area, but 1978. Apiotrigonia crassoradiata NAKANO: clearly differs in the plain subradial TASHIRO, Trans. Proc. Palaeont. Soc. costae of the posterior series and its Japan, N. S., no. 112, pp. 428-431, undulated costae of the anterior series. Text·figs. 3-5, pI. 54, fig. 5. Occurrence.-Examined specimens are from the lower sandstone of the Futaba Material.-KSG 2077-2085, internal and Group at Sakuradani, Hiromi-machi, external moulds from Fukkireura of Futaba-gun, Fukushima Pre f., from the Shimo-koshikijima Island, Kagoshima sandstone of the lower part of the Pref., KSG 2075-2076 and KE 2783, ex­ Furushiroyama Formation of the Uwajima ternal moulds from Omagari of Tomiuchi Group at Hiromi, Kitauwa-gun, Ehime (Hetonai), Iburi District, Hokkaido. KE Pref. and fine-grained sandstone of the 2127 and KSG 2086, from Himezuka of Kajisako Formation of the Sotoizumi Dogo, Matsuyama City, Ehime Pref. Group at Kajisako of Otochi, Kami-gun, Measurements (in mm).- Kochi Pref. This species is also reported Specimen Length Height Thickness from the Inukai Formation of the KSG 2075, Onogawa Group in Oita Pref. by TERA­ right ex. 42.0 32.2 9.9 OKA (1970). The holotype designated by mould KSG 2076, NAKANO (1957) was described from right in. 43.3 29.0 Taikorin, Oriki, Hirono-machi, Futaba­ mould gun, Fukushima Pref. This species is KSG 2077, left ex. 36.5 25.5 9.0 probably restricted to the Turonian mould (upper part of the Kajisako Formation) KSG 2078, and Coniacian (lower part of the Uwa­ left ex. 25.0 26.0 7.8 mould jima Group and the Inukai Formation of KSG 2079, the Onogawa Group). Inoceramus hobe­ right ex. 32.5 27.5 7.3 tsuensis Zone and I. uwajimensis Zone. mould KSG 2086, right valve 24.0 23.0 7.0

Apiotrigonia (Apiotrigonia) Remarks.-This species is characterized crassoradiata NAKANO by its entirely smooth area, bi- or trifurcated subradial costae in the poster­ Plate 25, Figs. 21 and 22 ior series in some adult specimens, 1938. Trigonia subovalis JIMBO, var. minor variable ornamentation of the anterior YABE and NAGAO: NAGAO and OTA· series and somewhat large size for TUME, Jour. Fac. Sci., Hokkaido Imp. Apiotrigonia S. str. The subradial costae, Univ., ser. 4, vol. 4, nos. 1-2, p. 42, about 12 in number, are variable in the pI. 1, fig. 9, non figs. 7 and 8. strength on the median part of the disk, 1957. Apiotrigonia crassoradiata NAKANO, as already mentioned in my previous 709. Pennatae trigoniids from Japan 191 paper (TASHIRO, 1978). The first costa Apiotrigonia (Apiotrigonia) of the posterior series begins to appear hetonaiana TASHIRO more posteriorly than that of Apiotrigonia (Apiotrigonia) minor (Y ABE and NAGAO). 1938. Trigonia subovalis var. minor Y ABE and The posterior carina is distinctly angu­ NAGAO: NAGAO and OTATUME, Jour. lated on the earlier half of the valve, Fac. Sci., Hokkaido Imp. Univ., ser. 4, but it rapidly becomes blunt on the later vol. 4, nos. 1-2, p. 42, pI. 1, figs. 7-8, half. non fig. 9. 1978. Apiotrigonia hetonaiana TASHIRO, Occurrence.-Holotype of this species Trans. Proc. Palaeont. Soc. Japan, was described by NAKANO (1957) from N.S., no. 112, pp. 425-428, text·fig. 2, the basal part of the Izumi Group at pI. 54, figs. 1-4. Yuasa of Onsen-gun, Ehime Pref. The specimens in my hand were collected Material.-KE 2776-2782, see TASHIRO, from several localities as mentioned 1978. below. Remarks.-Since this species was Black silitstone of the basal part of referred to Trigonia subovalis var. minor the Izumi Group at Himezuka of Dogo, YABE and NAGAO, by NAGAO and OTA­ Matsuyama City, Ehime Pref. ; Inoceramus TUME (1938), it has been listed as Apio­ (Sphenoceramus) schmidti Zone; Middle trigonia minor (Y ABE and NAGAO) by Campanian. Sandstone of the Lower NAKANO (1957), SAITO (1961), MAEDA and Member of the Middle Formation KA w ABE (1967) and HAY AMI (1975). (Member U-IIa) of the Upper Himenoura Recently TASHIRO (1978) discriminated Subgroup, at about 500 m south of this species from Trigonia subovalis var. Fukkireura, and about 200 m north of mino1' Y ABE and NAGAO, and described Fukkireura, Kashima-mura, Satsuma-gun, in detail as a distinct species of Apio­ Kagoshima Pref. Sandstone of Member trigonia, A. hetonaiana TASHIRO. U-IIa of the same subgroup at Yokohama This species is large for Apiotrigonia of Oe, Amakusa-machi, Amakusa-gun, s. str., and characterized by smooth and Kumamoto Pref.; Inoceramus (Sphenoce­ broad area, disapperance of the anterior ramus) sachalinensis Zone; Middle Cam­ series, finely crenulated inner anterior panian. Fine grained sandstone of the margin and numerous radial striae on Hakobuchi Group, at Omagari, Tomiuchi the subinternal surface of the anterior (Hetonai), Iburi District, Hokkaido ; half of the disk. The subradial costae Inoceramus (Sphenoceramus) orientalis of the posterior series are generally orientalis Zone; Lower Campanian. A weaker than in several resembling specimen collected by Mr. Makoto OKA­ species, e. g., A. (A.) minor (Y ABE and MURA of Kumamoto Univ. from the NAGAO), A. (A.) mikasaensis sp. nov., and Upper Yezo Group at Saku, Teshio­ A. (A.) crassoradiata NAKANO. This nakagawa-gun, Hokkaido (Inoceramus species is similar to Apiotrigonia (Apio­ (Sphenoceramus) schmidti Zone), is identi­ trigonia) obsoleta NAKANO, in having its fied with this species. smooth area and obscured costae of the This species is probably restricted to anterior series, but clearly differs in its Lower and Middle Campanian (Lower larger size of the valve and more Hetonaian). numerous subradial costae of the poster­ ior series than that of A. (A.) obsoleta (12 or more in this species; 4-7 in A. 192 Masayuki TASHIRO (A.) obsoleta). This species is probably tuberculated subradial costae on the closely related to Apiotrigonia (Apiotri­ posterior series. Apiotrigonia (Micro­ gonia) crassoradiata NAKANO. trigonia) imutensis (TASHIRO) is closely Occurrence.-Fukaushi Sandstone of the related to this species in having its Hakobuchi Group at Panketosano-sawa transverse striae on the area. This of Tomiuchi (Hetonai), Iburi District, species, however, differs from these Hokkaido; Maastrichtian (Upper Heto­ species of Microtrigonia in its less naian). Sandstone of the uppermost part developed subradial costae on the anter­ of the Chinomigawa Formation of the ior part of the disk. Upper Yezo Group, at Chinomigawa of Occurrence.-Black siltstone of the Urakawa, Hidaka District, Hokkaido, lower part? of the Upper Formation of which is somewhat younger than the the Lower Himenoura Subgroup (For­ Inoceramus (Sphenoceramus) schmidti Zone mation L-III) at Okoshiki beach of Oda­ or uppermost part of the Inoc. (Sphenoc.) machi, Uto City, Kumamoto Pref.; Inoc. schmidti Zone; Lower Maastrichtian or (Sphenoceramus) orientalis nagaoi, Hetero­ Uppermost Campanian?; Lowest Upper trigonia (Nakanotrigonia) himenourensis Hetonaian or uppermost Lower Heto­ (subgen. nov.), and Diplomoceras? sp. naian. The holotype (KE 2776) was occurred together with this species. The collected at Panketosano-sawa, Tomiuchi. bed is probably Lower Campanian This species presumably ranges from the (Lowest Hetonaian) in age. Black silt­ uppermost Campanian to Maastrichtian. stone of the Middle Formation of the same subgroup, at the western beach of Kugujima islet, Takado, Ryugadake­ Apiotrigonia (Apiotrigonia) machi, Amakusa-gun, Kumamoto Pref.; utoensis TASHIRO Inoceramus japonicus Zone; Upper San­ tonian (Uppermost Urakawan). 1972. Apiotrigonia utoensis TASHIRO, Trans. Proc. Palaeont. Soc. Japan, N.S., no. Apiotrigonia (Apiotrigonia) 86, p. 333, text-fig. 7, pI. 41, figs. 9-11. 1975. Apiotrigonia (Apiotrigonia) utoensis obsoleta NAKANO TASHIRO: HAY AMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 115. Text-fig. 5 1957. Apiotrigonia obsoleta NAKAKO, Japan. Material.-The specimens at my dis­ Jour. Geol. Geogr., vol. 28, nos. 1-3, p. posal are KE 1881 and 1882 which were 114, pI. 9, figs. 5-7. described in my previous study (TASHIRO, 1957. Apiotrigonia minor var. nankoi NAKA­ 1972, pI. 41, figs. 9 and 10). NO, Japan. Jour. Geol. Geogr., vol. 28, Remarks.-This species is discriminated nos. 1-3, p. 112, pI. 9, figs. 1-4. from the other species of Apiotrigonia 1972. Apiotrigonia obsoleta NAKAKO: T ASHI­ s. str. in its numerous transverse striae RO, Trans. Proc. Palaeont_ Soc. Japan, on the area and the subradial costae N.S., no. 86, p. 331, pI. 41, figs. 1-8, which are finely tuberculated on the non figs. 12 and 13. 1975. Apiotrigonia (Apiotrigonia) obsoleta anterior region of the posterior series. NAKANO: HAYAMI, Univ. Mus., Univ. This species resembles Microtrigonia spp., Tokyo, Bull, no. la, p. 115. e. g., Apiotrigonia (Microtrigonia) amanoi (NAKANO), A. (M.) postonodosa NAKANO, Material.-KE 1891-1903, from Okoshiki and A. (M.) imutensis (TASHIRO), in its beach of Oda-machi, Uto City, Kumamoto 709. Pennatae trigoniids from Japan 193 Prefecture. Description.-Shell small; test rather thin; umbo small, slightly prominent, a little opisthogyrous, located at a third to a fouth from the front of valve; anterior margin well rounded passing gradually into broadly arched ventral margin; siphonal margin narrow, well rounded, somewhat rostra ted to posterior; posterior margin nearly straight, postero­ dorsal margin gently concave; the costae of the posterior series occupy about a third of the disk; about 10 of the costae Text-fig. 5. Apiotrigonia (Apiotrigonia) of the anterior series concentric near obsoleta NAKANO, scale 5 mm. the umbo, regularly spaced and crowded; those on the succeeding median part of Aleasurements.-(see, TASHIRO, 1972) the same series broadly spaced, narrower Remarks.-The subradial costae of the than their interspaces, nearly subhori­ posterior series are variable in number, zontal, gradually weakened towards venter between 4 and 8. The costae of the and posterior, and generally effaced on anterior series are generally obscure in the median part of the disk; those on the majority of the specimens on the the ventral part of the same series central and anterior ventral part of the nearly obsolete; the costae of the disk; but occasionally discernible as posterior series very weak, broadly weak costellae in some specimens. The spaced, 4 to 8 in number, of which 3 or latter was once called Apiotrigonia so on the anterior region do not reach minor var. nankoi by NAKANO (1957), but the ventral margin; the first costa of there is gradation between it and the the series begins to appear at a point smoothish form in a fossil population about 5 mm distant from the umbo from one and the same locality. towards the posterior; area nearly This species distinctly differs from smooth except for several concentric other species of Apiotrigonia s. str. from costellae which are conjoined with the Japan, in its less numerous, and low and costellae of the escutcheon near the weak costae on the disk. It may have umbo; escutcheon depressed, rather been derived from the main lineage broad, ornamented with 10 or less than ranging from A. (A.) 11likasaensis to A. 10 oblique costellae; escutcheon carina (A.) hetonaiana (text-fig. 17). It resem­ indistinct; postero-ventral carina obtusely bles Trigonia maudensis WHITEA YES angulated near the umbo, but soon (PACKARD, 1921) from the Haida changing into low and broably rounded Formation of Queen Chalotte Island, ridge; median groove of the area very British Columbia, in having less numer­ shallow, but distinct; smooth marginal ous subradial costae of the posterior sulcus extended along the boundary series and somewhat weak costation on between the costate disk and the smooth the disk. That species, however, lacked area; inner surface smooth; inner the costellae on the escutcheon_ posterior ventral margin broadly crenu­ The specimens from the Himenoura lated on some specimens. Group of Kyushu are larger in size and 194 Masayuki TASHIRO less triangular in outline than those thogyrous, located at the fourth to fifth from the Izumi Group of Awaji Island. from the front of valve; anterior margin These differences could not be regarded semicircular; ventral margin weakly as specific but may be due to the changes arched; siphonal margin narrow, rost­ with growth. rated to posterior; posterior margin Occurrence.-Black siltstone of the nearly straight; the costae of the poster­ Upper Formation (Formation L-III) of ior series occupy about a half or less of the Lower Himenoura Subgroup, on the disk; the costae of the posterior Okoshiki beach and Hiraiwa beach of series strong but narrow, broadly spaced, Oda-machi, Uto City, Kumamoto Pref.; finely tuberculated near the postero­ Lowest Hetonaian (Lower Campanian). ventral carina, 7 to 10 in number, of Black siltstone of the Middle Formation which 3 or 4 on the anterior region (Formation L-II) of the same subgroup, do not reach the ventral margin; the at Wadanohana of Takado, Ryugadake­ first costa of the series begins to appear machi, Amakusa-gun, Kumamoto Pref.; at a point about 2 mm distant from the Inoceramus japonicus Zone; Upper Ura­ umbo towards the posterior; about 8 or kawan (Santonian). Holotype and para­ so costae of the anterior series con­ types by NAKANO (1957) were described centric near the umbo, closely spaced, from the Shichi shale (Uppermost connected with the costellae of escut­ Campanian) and Minato shale (Upper cheon and area, forming Rutitrigonia or Campanian) of the Izumi Group of Awaji Frenguelliella-like concentric ornament­ Island, Kinki District. This species ation; those on the median part of the ranges probably from Upper Santonian same series broadly spaced, narrower to Campanian. than their interspaces, nearly horizontal, about 5 in number, gradually weakened towards ventral and posterior; those on Apiotrigonia (? Apiotrigonia) the ventral part of same series nearly dubia sp. nov. obsolete; area ornamented with two Plate 25, Figs. 11-17, Text-fig. 6 sorts of costellae; subhorizontal costellae occupy nearly full surface of the area 1972. Apiotrigonia aff. obsoleta NAKANO: except for the siphonal part, conjoined T ASHlRO, Trans. Proc. Palaeont. Soc. with the costellae of escutcheon; sub­ Japan, N. S., no. 86, pI. 41, figs. 12 and 13. vertical costellae also occupy nearly full surface of the area except the siphonal Material.-Holotype KSG 2087, is a left part, conjoined with the subradial costae valve, from Azenotani, Sakai City, Izumi on the posterior series of the disk; those Mountains; KSG 2089 and KE 1935-1936 two sorts of costellae cross each other, (paratypes), from the same locality of forming fine tuberculations; escutcheon holotype; KSG 2090-2091 (para types) rather broad, lanceolated, ornamented from Masuno, Ushibuka City (Amakusa­ with 8 or more tuberculated subhorizontal Shimojima Island), Kumamoto Pref. The costellae; postero-ventral carina well specimens are external and internal remarked; escutcheon carina and median moulds. groove of the area nearly invisible; Description.-Shell small, pyriform to inner posterior ventral margin broadly trigonal ovate, longer than high; umbo crenulated; growth lines very weak or small, slightly prominent, a little opis- almost invisible. 709. Pennatae trigoniids from Japan 195 lation on the area, but is distingushable from that species in having less deve­ loped subradial costae on the disk. It is also similar to Apiotrigonia (Micro­ trigonia) postonodosa NAKANO in the finely tuberculated subradial costae in the posterior series and the features of the ornamentations on the area, but is not characterized by so strong and so well developed subradial costae of the poster­ ior series as in that species. The sub­ generic assignment of this species to Text·fig. 6. Apiotrigonia (?Apiotrigonia) Apiotrigonia (s. str.) is provisional, since dubia sp. nov., scale 5 mm. it has some characters which recall us Microtrigonia. Occurrence.-Fine-grained sandstone of Measurements (in mm).- the Azenotani Shale of the Izumi Group Specimen Length Height Thickness at Azenotani, Sakai City, Izumi Moun­ KSG 2087, left ex. 9.5 6.5 1.6 tains. Fine-grained sandstone of the mould same formation at Takinoike, Izumi­ KSG 2088, Sano City, Izumi Mountains. Sandstone right ex. 11.9 8.0 1.9 mould of the Middle Member (Member U-IVb, KSG 2089, TASHIRO and OTSUKA, 1978) of the Upper left in. 10.0 7.'J Himenoura Subgroup, at about 400 m mould west of Masuno (roadside exposure), KSG 2090, left ex. 10.5 7.S 1.2 Oniki-machi, Ushibuka City, Kumamoto mould Pref.; Upper Hetonaian (Maastrichtian). KE 1935, This species is restricted probably to the left ex. 11.0 7.5 mould uppermost Campanian and Maastrichtian, KE 1936, being one of the latest species of the left ex. 15.0 9.5 pennatae trigoniids. mould

Comparison.-This species resembles Subgenus Microtrigonia NAKANO, 1957 Apiotrigonia (Apiotrigonia) obsoleta NA­ KANO in ornamentation of the disk, but Type-species: Microtrigonia amanoi differs in its tuberculated sculpture on NAKANO, 1957; Upper Himenoura Sub­ the area and the finely tuberculated group in Southwestern Japan. Upper subradial costae in the posterior series. Campanian (Lower Hetonaian). It is similar to Apiotrigonia (Apiotrigonia) Diagnosis.-Shell small, roundly sub­ utoensis TASHIRO in its finely tuberculated triangular or pyriform; umbo weakly subradial costae, but differs clearly in opisthogyrous, located anteriorly; disk that the latter has transverse costellae ornamented with two sorts of costae: on the area and numerous concentric the concentric plain costae on umbonal costae in the anterior series. It resembles part and the subradial ones tuberculated Apiotrigonia (Microtrigonia) amanoi generally, appearing on the outer side of (NAKANO) in the same type of costel- outskirts of the former; escutcheon 196 Masayuki TASHIRO narrow with tuberculated oblique or transverse costellae; area broad with or without oblique tuberculated costellae which conjoined with the costellae of the escutcheon; dorsal carina indistinct; postero ventral carina rather distinct, angulated near the umbo; median groove of the area weak or indistinct. Remarks.-Microtrigonia was eata­ blished by NAKANO (1957) as a distinct genus. It was considered as a derivative A from Apiotrigonia s. str. by NAKANO (1957) and TASHIRO (1972). The intimate relationships between certain species of Apiotrigonia s. str. and Microtrigonia are suggested by many features. For instance, a specimen of Apiotrigonia (Microtrigonia) imutensis (TASHIRO) (pI. 26, fig. 10), shows the subradial costae of the posterior series, like those of Apiotrigonia (Apiotrigonia) minor (Y ABE and NAGAO) (pI. 26, fig. 18) and A.

(A.) crassoradiata NAKANO (pI. 26, figs. B 21, 22) (see Text-figs.). This specimen may, however, be a malform. Apiotri­ gonia (Microtrigonia) imutensis (TASHIRO) is closely related to Apiotrigonia (Apio­ trigonia) utoensis TASHIRO in the features of the area and the tuberculated costae ," of the posterior series. The immature . stage of Microtrigonia is nearly identical ., , , with that of Apiotrigonia s. str. in the Frenguelliella- or Rutitrigonia-like con­ centric plain costae of the umbonal region (see TASHIRO, 1972, text-fig. 1). A younger shell of Apiotrigonia (Micro­ - ..... __ .. --- trigonia) postonodosa NAKANO does not Text-fig. 7. Examples showing the show the typical characters of Micro­ relationships between Apiotrigonia s. str. trigonia but has fine tuberculate costae and Microtrigonia. Note the "common of the posterior series and less developed zigzag ribbing" appearing on the disks on subradial costae on the anterior part of three different species of the pennatae the disk. This suggests that A. (M.) trigoniids. A: Apiotrigonia (Api?trigonia) postonodosa may have descended from minor (Y ABE and NAGAO); B: A. (Micro­ some species of Apiotrigonia s. str. trigonia) imutensis (TASHIRO); C: A. (A.) crassoradiata NAKANO, scale 5 mm. Microtrigonia is distinguished from Apiotrigonia s. str. in its tuberulated 709. Pennatae trigoniids from Japan 197 subradial costae which are developed on A. (M.) imutensis (TASHIRO, 1972); a certain part of the disk. Several Campanian species of Apiotrigonia s. str., Turkesta­ A. (M.) postonodosa NAKANO, 1957; nella nov. and Dampietrigonia nov., have uppermost Campanian or Maastri­ subradial sculptures on the anterior part chtian of the disk. For instance, Apiotrigonia A. (M.) sp.; Maastrichtian (this paper) (Apiotrigonia) hetonaiana TASHIRO have Distribution.-Campanian and Maastri­ subinternal striae on the part, Apiotri­ chtian (Hetonaian) of Japan. Examples gonia (Dampietrigonia) dampierensis outside of Japan have not yet been SKWARKO have fine radial striae, and confirmed. Apiotrigonia (Tu rkestanella) tu rkestanensis (ARCHANGELSKI) is characterized by the Apiotrigonia (Microtrigonia) Microtrigonia-like subradial costae. Apio­ amanoi (NAKANO) trigonia (Apiotrigonia) minor (Y ABE and NAGAO) and A. (A.) crassoradiata NAKANO Plate 26, Figs. 1-6, Text-fig. 9 are very often characterized by the 1957. Trigonia subovalis var. minor Y ABE obliquely costated anterior series. Such and NAGAO: AMANO, Kumamoto Jour. subinternal or external subradial sculp­ Sci., ser. B, vol. 2, no. 2, p. 57, pI. 1, tures and oblique costations on the fig. 19. anterior part of the disk, appearing in 1957. Microtrigonia amanoi NAKANO, Japan. Apiotrigonia s. str., Turkestanella nov. Jour. Ceol. Ceogr., vol. 28, nos. 1-3, and Dampietrigonia nov., are probably p. 117, pI. 9, figs. 21 and 22. 1957. Apiotrigonia tuberculata NAKANO, suggested the relationships between them Japan. Jour. Ceol. Ceogr., vol. 28, and Microtrigonia. And the subradial nos. 1-3, p. 115, pI. 9, figs. 15 and 16. elements probably indicate one of the 1972. Microtrigonia amanoi NAKANO: TASHI­ common characters in the pennatae RO, Trans. Proc. Palaeont. Soc. Japan, trigoniids. I think that these four taxa, N. S., no. 86, pI. 40, figs. 26 and 27 Apiotrigonia s. str., Turkestanella nov., (without description). Dampietrigonia nov. and Microtrigonia, 1975. Microtrigonia amanoi NAKANO: HA­ can not be distinguished generically. I y AMI, Univ. Mus., Univ. Tokyo, Bull. regard Microtrigonia as a subgenus of no. 10, p. 116. Apiotrigonia s. 1. Microtrigonia is as yet 1975. Microtrigonia tuberculata (NAKANO): unknown from the foreign Cretaceous HA YAMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 116. sediments. Its known occurrence is 1976. Microtrigonia amanoi NAKANO: TA­ restricted to the Campanian and SHIRO, Palaeont. Soc. Japan Sp. Pcp. Maastrichtian of Japan. It seems likely no. 19, p. 57, pI. 7, figs. 10-14. that Microtrigonia is one of the end members of the trigoniid lineages, which Material.-KE 1933, 1934, 2130 and 2131, became extinct by the end of Cretaceous. external moulds, collected from Ukimizu, The following species from Japan are Shimo-Koshikijima Island, Kagoshima referable to the subgenus Microtrigonia: Pref. (type locality by Nakano, 1957). A. (M.) amanoi (NAKANO, 1957); Upper KE 2134, external mould, from Oe of Campanian (type-species of Micro­ Amakusa-machi, Amakusa-shimojima . trigonia) Island, Kumamoto Pref. KE 2132-2133, A. (M.) minima (NAKANO, 1957); Maas­ from Himezuka of Dogo, Matsuyama trichtian City, Ehime Pref. KSG 2092-2094, internal 198 Masayuki TASHIRO

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Z I- ~ I Q :2 A I z0 I:)- lLJ U 709. Pennatae trigoniids from Japan 199 and external moulds, from Azenotani, than their interspaces, regularly spaced, Sakai City, Izumi Mountains. KSG 2095- about 10 in number, occupying umbonal 2098, internal and external moulds, from region which is about one fourth in height Fukkireura of Shimo-Koshikijima Island. from the umbo; several imperfect con­ KSG 2099-2100, external moulds, from centric costae which are crossed by the Hanzanji, A waji Island, Hyogo Pref. other sort of costae, forming tubercu­ KSG 2101, external mould, from Hirono lations, recognizable under the umbonal of A waji Island. The specimens registered concentric costae, weakened and broadend as KE, were already described by towards the venter; the other element TASHIRO (1976). of costae subradial, strong, tuberculated, Description.-Shell trigonally ovate, broader than their interspaces, occupying moderately inflated; umbo slightly the main part of the disk outside the opisthogyrous or nearly orthogyrous, umbonal region, about 9 costae of small, a little elevated from the dorsal posterior extended from the postero­ margin, located at about two-fifths from marginal carina to the ventral margin, the front of the valve; anterior margin the other 6 or more costae appearing on semicircular; ventral margin broadly the anterior marginal part and the arched; siphonal margin obliquely trunc­ anterior part of ventral margin, oblique or ated, occupying about a half lenght of nearly vertical on the middle part on the the height of the valve; postero-dorsal ventral, soon bended obliquely on the margin nearly straight or slightly convex ventral part; escutcheon very narrow but a little concave near the umbo; with 10 or more oblique and tuberculated antero-siphonal margin bluntly angulated ; costellae; area broad, elongated trian­ disk ornamented with two sorts of gular; 7 or so plain and concentric costae; concentric plain ones, narrower costellae which conjoined with the costae of the disk, crowded near the umbo of the area; 10 or so tuberculated and oblique costellae, which conjoined with the costellae of the escutcheon, widely spaced, narrower than their interspaces, occupying the other part of the area; escutcheon carina distinct near the umbo, but obscure on the posterior; the boundary of the area and escutcheon visible only as a depressed line of the escutcheon; postero-marginal carina distinctly angulated, weakly concave; median groove of the area indistinct; Text-fig. 9. Apiotrigonia (Microtrigonia) inner surface smooth; inner posterior amanoi (NAKANO), scale 5 mm. ventral margin broadly crenulated ; in the

Text-fig. 8. Diagram showing the stratigraphical occurrences and the presumed line of descent in Apiotrigonia s. str. from Japan. A: Apiotrigonia (Apiotrigonia) mikasaensis sp. nov., B: A. (A.) minor (Y ABE and NAGAO), C: A. (A.) crassoradiata NAKANO, D: A. (A.) hetonaiana TASHIRO, E: A. (A.) undulosa NAKANO, F: A. (A.) utoensis TASHIRO, G: A. (A.) obsoleta NAKANO, H: A. (?A.) dubia sp. nov., scale 5 mm. 200 Masayuki TASHIRO umbonal region a marginal sulcus-like "rostrate", the "typical" and the "tuber­ narrow band runs under the postero­ culate" forms (see Text-fig. 11). They ventral carina; the band ornamented with are, however, not clearly discriminated fine plain vertical costae which conjoined specifically or subspecifically, since the with the concentric costae of the disk intermediate specimens are usually found of I:lmbonal region, forming rever:oe L between them. The rostrate form shape. generally occurs in the Lower Campanian or the lowest part of the Upper Cam­ Measurements (in mm).- panian of the Izumi Group and the Upper Specimen Length Height Thickness Himenoura Subgroup. The typical form KSG 2095, is found from the Upper Campanian and right ex. 18.0 14.0 3.3 mould Lowest Maastrichtian? of the Upper Himenoura Subgroup, the tuberculate form KSG 2096, 14.5 10.8 1.9 left valve from the Maastrichtian and the upper­ KSG 2097, left ex. 12.3 8.5 1.7 most Campanian of the Izumi Group of mould Awaji Island and the Izumi Mountains. KSG 2098, The features of each form are as right ex. 11.9 9.2 1.7 mould follows.- KSG 2093, Rostrate form :-Shell pyriform and right ex. 12.5 8.9 2.5 roundly subtriangular; area narrow than mould in the typical form; umbonal concentric KSG 2092, left ex. 8.5 6.3 1.6 costae less numerous and occupy a mould narrower area. Typical form :-Shell subtriangularly Remarks.-The holotype (GKU. MA. ovate; umbo improminent; area broader 00001) designated by NAKANO (1957) from than in the rostrate form; escutcheon the Upper Member of the Middle For­ very narrow. mation of the Upper Himenoura Subgroup Tuberculate form: - Shell trigonally (Member U-lIb), at Ukimizu of Imuta, ovate, much inflated. Kashima-mura, Shimo-Koshikijima Island, The rostrate form somewhat resembles Kagoshima Pref. (=Imuta Formation at Apiotrigonia (Microtrigonia) imutensis Ukimizu of Imuta by AMANO, 1957, and (TASHIRO) in its rostrated posterior NAKANO, 1957), is small (11.6 mm in siphonal part, but differs in its costellae length). It seems to represent a young on the area and less numerous costae of stage, being probably a umbonal frag­ the anterior and posterior series. The mental specimen. The largest specimen tuberculate form is similar to Apiotri­ (KE 1934; see TASHIRO, 1976) in my gonia (Microtrigonia) postonodosa NAKA­ collection from the type locality is NO, in its features of costae on the disk, measured about 25 mm in length. The but differs in its weak and more dis­ latio of length to height is variable tinctly tuberculate costae of the posterior between 4/5 and 3/5. series. The Frenguelliella- or Rutitrigonia­ This species shows gradual changes in like stage is more distinct in the tuber­ outline and surface sculptures in ac­ cuI ate form and more persistent than in cordance with the stratigraphic sequence, A. (M.) postonodosa. Apiotrigonia tuber­ in which three representative forms are culata NAKANO (1957) is identical with recognizable. They are called here the the tuberculate form. What was listed 709. Pennatae trigoniids from Japan 201

under "Apiotrigonia tuberculata" by Material.-Holotype is KE 1887 (T A­ TANAKA and TERAOKA (1973), and MAE­ SHIRO, 1972) from Ukimizu of Imuta, DA and KA W ABE (1967) from Shimo­ Kashima - mura (Shimo - Koshikijima Koshikijima Island, Kagoshima Pref., is Island), Satsuma-gun, Kagoshima Pref. probably better to be transferred to KSG 2102-2104, from Fukkireura of Imuta, typical form. Kashima-mura. KSG 2105-2106 from Occurrence. - Black siltstone of the Yokohama of Oe, Amakusa-machi, Upper Member of the Middle Formation Amakusa-gun, Kumamoto Pref. KSG of the Upper Himenoura Subgroup 2107 from Himezuka of Dogo, Matsu­ (Member U-lIb), at Ukimizu of Kashima, yam a City, Ehime Pref. KSG 2108-2109 Satsuma-gun, Kagoshima Pref. Black from Oshima islet of Ushibuka City, silty sandstone of the Lower Member Amakusa-Shimojima, Kumamoto Pref. of the Middle Formation of the Upper Description.-See TASHIRO, 1972, p. 335. Himenoura Subgroup, at Fukkireura of Kashima. Fine-grained sandstone of the Measurements (in mm).- Lower Member of the Middle Formation Specimen Length Height Thickness KSG 2102, 4.0 of the Upper Himenoura Subgroup right valve 25.0 17.0 (Member U-lIa) at Yokohama of Oe, KSG 2103, 17.0 12.2 3.0 Amakusa-machi, Amakusa-gun, Kuma­ right valve moto Pref. Black siltstone of the basal KSG 2104, left ex. 16.7 12.5 2.8 part of the Izumi Group at Himezuka of mould Dogo, Matsuyama City, Ehime Pref. KSG 2105, right ex. 24.0 15.0 4.0 Fine-grained sandstone or siltstone of mould the Azenotani shale of the Izumi Group KSG 2106, at Azenotani, Sakai City, Izumi Mountains. right ex. 22.4 16.5 3.9 Silty sandstone of the Shichi shale of mould KSG 2107, the Izumi Group at Hirono, Awaji Island, left ex. 18.4 14.7 4.0 Hyogo Pref.; Inoceramus (Sphenoceramus) mould schmidti Zone. Campanian and probably KSG 2108, left ex. 11.2 9.3 2.6 also an uncertain part of the Maastri­ mould chtian. KSG 2109, left ex. 13.2 12.5 3.0 mould Apiotrigonia (Microtrigonia) imutensis (TASHIRO) Remarks.-This species is clearly dis­ tinguished from Apiotrigonia (Microtri­ Plate 26, Figs. 7-12 gonia) amanoi(NAKANO) in its smooth area, 1972. Microtrigonia imutensis TASHIRO, finer tuberculations of the subradial costae Trans. Proc. Palaeont. Soc. Japan, and more numerous and more crowded N. S., no. 86, p. 335, text-fig. 9, pI. 40, concentric costae on the disk. This figs. 24 and 25. species shows changes in the arrange­ 1975. Microtrigonia imutensis TASHIRO: ment of the surface ornamentation in HAYAMI, Univ. Mus., Univ. Tokyo accordance with the stratigraphic se­ Bull. no. 10. p. 116. 1976. Microtrigonia imutensis TASHIRO: quence. Three representative varieties TASHIRO, Palaeont. Soc. Japan, Sp. aredis criminated: pseudo-utoensis form Pap. no. 19, pI. 7, -figs. 7 and 8 (for (Text-fig. 3-A), radiate form (Text-fig. comparison) . 3-B and C) and the typical form (Text- 202 Masayuki TASHIRO fig. 3-D). Since an intermediate form moto Pref. (Amakusa-Shimojima Island), usually occur in every case, these three and from the same formation at Fukki­ forms are not treated as subspecies. reura of Kashima-mura (Shimo-koshiki­ The features of the three forms are as jima Island). Inoceramus (Sphenoceramus) follows.- orientalis orientalis is known from the pseudo-utoensis form: - Area orna- locality of Oshima islet. While Inocer­ mented with fine but distinct concentric amus (Sphenoceramus) elegans pseudo­ or transverse striae, as in Apiotrigonia sulcatus was collected from the locality (Apiotrigonia) utoensis TASHIRO; subradial of Fukkireura. The radiate form is costae somewhat less numerous (about known from the black siltstone of the 15) and more distinctly tuberculated than basal part of the Izumi Group at Hime­ in the other two forms; siphonal margin zuka of Dogo, Matsuyama City, Ehime moderately rostra ted. Pref., occurring together with Inoceramus radiate form :-Siphonal margin rost­ (Sphenoceramus) schmidti. Another local­ rated; subradial costae well developed ity of the radiate form is the sandstone on almost the entire surface of the disk, of the Lower Member of the Middle except for the umbonal concentric Formation of the Upper Himenoura Sub­ Rutitrigonia or Frenguelliella-like series; group (Member U-IIa) at Yokohama of the tubercles of the subradial costae Oe, Amakusa-machi, Amakusa-gun, Kuma­ very fine. moto Pref. (Amakusa-Shimojima Island), typical form :-Area broader than in and the sandstone of the same member the other two forms; siphonal margin at Fukkireura of Kashima-mura, Shimo­ somewhat truncated; the subradial costae Koshikijima Island. Inoceramus (Spheno­ about 25, being more numerous than in ceramus) sachalinensis is known from the other forms. same locality as this form in Amakusa­ The radiate form was sometimes listed Shimojima Island. This species is pro­ erroneously as Trigonia ogawai (YEHARA, bably restricted to occur in the Cam­ 1923) or Apiotrigonia postonodosa (HATAE, panian (Lower Hetonaian); Inoceramus 1959, 1960; MIKI, 1972) from the Lower (Sphenoceramus) orientalis orientalis Zone Member of the Middle Formation of the and Inoc. (SPhenoc.) schmidti Zone. Upper Himenoura Subgroup at Yokohama of Oe. "Trigonia" sp. (n. sp.) of AMANO Apiotrigonia (Microtrigonia) (1962), from the same member at Oe, is probably another example of this radiate postonodosa NAKANO form. Plate 26, Figs. 13-17, Text.fig. 10 Occurrence.-The holotype came from the black siltstone of the Upper Member 1957. Apiotrigonia postonodosa NAKANO, of the Middle Formation of the Upper japan. jour. Ceol. Ceogr., vol. 28, nos. Himenoura Subgroup at Ukimizu of 1-3, p. 114, pI. 9, figs. 8-14. Imuta, Kashima-mura, Satsuma-gun, 1972. Apiotrigonia postonodosa NAKANO: Kagoshima Pref. (Shimo-koshikijima TASHIRO, Trans. Proe. Palaeont. Soc. japan, N.S., no. 86, pI. 40, figs. 20-23, Island) (T ASHlRO, 1972). The pseudo­ text.figs. 5 and 1-c, 3-d, and 6-B. utoensis form occurs in the black siltstone 1975. Apiotrigonia postonodosa NAKANO: of the Lower Formation of the Upper HAYAMI, Univ. Mus., Univ. Tokyo, Bull. Himenoura Subgroup (Formation U-I) no. 10, p. 115 at Oshima islet of Ushibuka City, Kuma- 1976. Apiotrigonia postonodosa NAKANO: 709. Pennatae trigoniids from Japan 203

TASHIRO, Palaeont. Soc. Japan, Sp. on the anterior part short, surrounded Pap., no. 19, pI. 7, figs. 1-3. by the outskirts of the anterior series, bi- or trifurcate near the antero-ventral Material.-KE 1927-1931 and KSG part; Frenguelliella-like stage of the 2113-2114, from Yotsuinosako of Kami­ umbonal region limited only with a few hira, Miyanokawachi, Kawaura-machi, concentric plain costae; escutcheon Amakusa-Shimojima Island; KE 2117- depressed, very narrow, ornamented with 2119, from Ono of Hongo, Miyano­ 10 or more transverse costellae which kawachi; All the specimens are internal are finely tuberculated, narrower than and external moulds. their interspaces, and conjoined with the Diagnosis. - Shell medium for Micro­ costellae of the area; area broad, trigonia but small for Apiotrigonia s. 1., ornamented with horizontal or oblique pyriform to rounded subtrigonal, fairly costellae which are finely tuberculated, inflated; umbo slightly opisthogyrous, narrower than their interspaces, number not prominent, located at about one­ about 15, of which 3 or so near the third to one-fifth from the front of the siphonal margin somewhat weaked and valve; anterior margin well rounded; irregularly waved; escutcheon carina ventral margin long, broadly arched; indistinct except near the umbo; postero­ siphonal margin narrow, rounded, some­ ventral carina angulated on a half what rostrated to the posterior; postero­ length of itself from the umbo but soon dorsal margin straight or weaklyc oncave, changing into roundly angulated ridge occupying about a half length of the on the posterior half; median groove on valve; ratio of length to height about the area indistinct; inner surface smooth; two-thirds in the adult stage but larger posterior inner ventral margin broadly in younger stages; disk ornamented with and strongly crenulated; inner adductor two series of costae: the anterior and scars and hinge structures are strongly the subradial series, those of the former impressed for pennatae trigoniids. concentric, plain, widely spaced, some­ what narrower than their interspaces; 5 or 6 costae on the umbonal region distinct for about 4 mm in distance from the umbo towards the venter; the succeeding several costae gradually weakened and broadly spaced, and con­ nected with the subradial series of costae on the anterior part; and finally those on the ventral part of the adult stage, over 10 mm or so in length, become nearly indistinct; the subradial series of costae very strong, but narrower than their interspaces, finely tuberculated; about 10 costae from the rear of the valve extended from the postero-ventral carina Text·fig. 10. Apiotrigonia (Microtrigonia) towards the ventral margin, nearly postonodosa NAKANO, scale 5 mm. straight, occupying about three-fourths in length of the disk; 7 or more costae 204 Masayuki TASHIRO Measurements (in mm).- broad area, but differs in its finer Specimen Length Height Thickness tubercles on the costae, more rostra ted KE 1927, siphonal margin and the more restricted left ex. 18.4 13.3 3.0 mould FrengueHiella-like stage on the umbonal KE 1928, part. The rostrate form of Apiotrigonia right ex. 12.5 10.5 2.6 (Microtrigonia) imutensis (TASHIRO) some­ mould what resembles this species in its KSG 2110, right in. 13.3 9.7 2.7 rostra ted outline, but clearly discrimin­ mould ated by its smooth area and more KSG 2112, numerous subradial costae of the posterior right ex. 13.4 9.4 2.4 mould series. KSG 2113, Occurrence.-Fine sandstone of the left ex. 14.8 9.8 2.3 Lower Member of the Upper Formation mould of the Upper Himenoura Subgroup KSG 2114, right ex. 12.3 10.8 3.2 (Member U-I1Ia), at Yotsuinosako of mould Kamihira, Ono of Hongo, Keijigahama KSG 2119, left ex. 14.9 9.5 3.6 and Nodden, all in Miyanokawachi, mould Kawaura-machi, Amakusa-gun, Kuma­ moto Pref. The type locality by NAKANO Remarks.-This species was referred (1957) (Nodden of Miyanokawachi) is of to Apiotrigonia s. str. by NAKANO (1957). nearly the same horizon as the four As the holotype (GH. NM.00004) and the localities of this paper. ?Siltstone of paratypes (GH. NM.00005-6, GK. H.6021) the Shichi shale of the Izumi Group, at are small, the subradial costae which are Hanzanji, Shichi-mura, Mihara-gun, Hyogo characteristic to Microtrigonia are not Pref. (Awaji Island); The geological age shown in these type specimens. JUdging of Member U-I1Ia of the Upper Himenoura from the specimens which I collected Subgroup may be referrable to the upper­ from the same stratigraphic unit in most Campanian or Lower Maastrichtian. Amakusa, the type specimens undoubtedly The Shichi Shale of the Izumi Group was represent the younger stage of this assigned to the Uppermost Campanian. species. The largest specimen in my collection is about 20 mm in length. Besides the material from the Himeno­ Apiotrigonia (lvIicrotrigonia) sp. indet. ura Group, this species was also described Plate 26, Figs. 19, 20 by NAKANO (1957) from the Shichi shale of the Izumi Group at Hanzanji, Mihara­ Material.-Three imperfect specimens gun, Awaji Island. As the specimens (KSG 2120-2122) and two internal moulds from the Izumi Group in my collection (KSG 2123-2124), from Panketosanosawa are very small, it is questionable whether of Tomiuchi (Hetonai), Iburi District, they are referrable to this species or to Hokkaido. the tuberculate form of Apiotrigonia Description.-Shell small, roundly tri­ (Microtrigonia) amanoi (NAKANO). In angUlar, longer than high, fairly strongly fact, this species is closely related to the inflated; umbo slightly opisthogyrous, tuberculate form of A. (M.) amanoi, less prominent; anterior margin semi­ in having the tuberculated subradial circular; ventral margin broadly arched; costae and the oblique costellae on the siphonal margin small, somewhat angu- 709. Pennatae trigoniids from Japan 205 lated; posterior dorsal margin nearly Hetonaian). straight but a little concave near the umbo; disk ornamented with two series Apiotrigonia (Microtrigonia) of costae; the subradial costae of the posterior series tuberculated, of which 8 minima (NAKANO) or more extended from the postero­ 1957. Microtrigonia minima NAKANO, Japan. ventral carina to the ventral margin, Jour. Geol. Geogr. vol. 28, nos. 1-3, occupying the posterior half of the disk, p. 119, pI. 9, figs. 21 and 22. whereas several others appear on the 1975. Microtrigonia minima NAKANO: HAYA­ antero-ventral part, short, extending MI, Univ. Mus., Univ. Tokyo, Bull. no. from a point at some distance from the 10, p. 116. umbo to the ventral margin; concentric Remarks.-There is no example of this costae of the anterior series plain; area species in my collection. I indicate it broad with oblique costellae; escutcheon only for completing the list of species. very narrow with numerous transverse Age and distribution.-Campanian and costellae; escutcheon carina indistinct; Maastrichtian (Hetonaian): Shichi Shale postero-ventral carina angulated near and Kitaama Sandstone of the Izumi the umbo, but roundly elevated on its Group in Awaji Island (NAKANO, 1957). posterior half; inner surface smooth; inner posterior ventral margin broadly Subgenus Dampietrigollia nov. crenulated, numbering about 6; inner posterior dorsal margin crenulated, about Type-species: 'Apiotrigonia' dampier­ 12; inner siphonal median ridge distinct. ens is SKWARKO, 1969; Aptian; Western Australia. Measurements (in mm).- Diagonosis.-Shell pyriform; umbo opi­ Specimen Length Height sthogyrous, located anteriorly; disk orna­ KSG 2120, right valve 7.8 5.6 KSG 2123, left in. mould 15.0 11.7 mented with two series of costae; sub­ radial costae occupying on the whole Remarks.-Although the details of sur­ surface of the disk but weak on the face ornamentation of the available anterior half, generally tuberculated; specimens are not clear, this species concentric costae plain, appear on the resembles Apiotrigonia (Microtrigonia) anterior half of the disk; area and postonodosa NAKANO rather than other escutcheon smooth; escutcheon and species of Microtrigonia, in its inflated postero-ventral carinae weak or indistinct valve and less numerous subradial costae. except near the umbo; median groove A. (M.) postonodosa, differs from this of the area weak. species in its strong costae in both Remarks.-This new subgenus is pro­ series on the disk. So far it is only posed on the basis of 'Apiotrigonia' known species of Microtrigonia, from the dampierensis SKW ARKO, 1969, from the Cretaceous of Hokkaido. Melligo Quartzite of Dampier Peninsula, Occurrence.-Fukaushi Sandstone of the Western Australia. It is characterized Hakobuchi Group at Panketosanosawa of by the smooth area and escutcheon, and Tomiuchi (Hetonai), Iburi District, the subradial costae which cover the Hokkaido. The part immediately below whole surface of the disk including the the Zone of Inoceramus (?Sphenoceramus) anterior part. Trigonia calderoni (CAS­ hetonaianus; Maastrichtian (Upper TILLO and AGUILERA) (CRAGIN, 1905; 206 Masayuki T ASH! RO

z <{ l­ I U 0::: I­ (f) w <{ ~

z <{ z <{ a. ~ <{ U

A ..... 709. Pennatae trigoniids from Japan 207 STOY ANOW, 1949; SKW ARKO, 1970), from area· and escutcheon ornamented with the Jurassic formation of Mexico and oblique costellae; postero-ventral carina Texas, is similar to this type-species distinct; escutcheon carina obscure. in its smooth escutcheon. While SKW ARKO Remarks.-This new subgenus is similar (1970) referred T. calderoni to Apiotri­ to Microtrigonia in its subradial costae gonia, NAKANO (1971) classified T. which develop on the anterior part of calderoni as a member of Heterotrigonia, the disk, but differs in its broader and because of the presence of weak radial less numerous subradial costae, and less costellae on the area of T. calderoni. A numerous concentric costae on the disk. few Albian species, Trigonia newcombei Distribution.-Cenomanian; Turkestan. PACKARD (1921) and Trigonia maudensis WHITE AVES by PACKARD (1921) from the Genus Heterotrigonia Cox, 1952 Haida Formation (Albian) of Queen Charlotte Island, resemble the type­ Type-species: Trigonia diversicostata species in having the smooth escutcheon WHITE AVES, 1876; Albian; British and area. Dampietrigonia is, however, Colombia. distinguishable from them in that its Diagnosis. - Shell small to large, subradial costae extend to the anterior pyriform and trigonally ovate; umbo part. Microtrigonia, Nakanotrigonia nov. opithogyrous, located anteriorly; disk and Turkestanella nov. are characterized ornamented with two series of costae; by the subradial costae which appear on subradial ones developed generally on the anterior part of the disk. The sub­ the posterior part of the disk; extending radial costae of them are, however, sometimes to the anterior part; the stronger than those of this new subgenus, costae of the other series appear on the and do not develop near the umbo. anterior part of the disk, generally sub­ Distribution.-Aptian; Western Aust­ horizontal but may be variable in the ralia. arrangement and intensity; area orna­ mented with radial costellae; escutcheon Subgenus Turkestanella nov. ornamented with oblique or subhorizontal costellae, or smooth; postero-ventral Type-species: Trigonia turkestanensis carina and escutcheon carina weak ARCHANGELSKI, 1916 [=Megatrigonia except near the umbo; median groove (Apiotrigonia) turkestanensis : POJARKOVA, of the area very weak or indistinct. 1978J; Cenomanian; Turkestan. Remarks.-Heterotrigonia was estab­ Diagnosis.-Shell trigonal-ovate; umbo lished as a distinct genus by Cox (1952) small, less prominent, slightly opistho­ on the basis of Trigonia diversicostata gyrous, located anteriorly; disk orna­ WHITE AVES, from the Haida Formation mented with Microtrigonia-like costae; of the Queen Charlotte Islands, British

Text·fig. 11. Diagram showing the stratigraphical occurrence and possible lines of descent in Apiotrigonia (Microtrigonia) from Japan. A·D: Apiotrigonia (Microtrigonia) imutensis (TASHIRO), A. pseudo·utoensis form, B. and C. radiate form, D. typical form; E·H: Apiotrigonia (Microtrigonia) amanoi (NAKANO), E and F. rostrate form, G. typical form, H. tuberculate form (=Microtrigonia tuberculata NAKANO), I: Apiotrigonia (Microtrigonia) minima (NAKANO), J: Apiotrigonia (Microtrigonia) postoncdosa NAKANO, scale 5 mm. 208 Masayuki TASHIRO

Columbia. It is distinguishable from 1894. Trigonia subovalis JIMBO, Pal. Abh., Apiotrigonia in its radial costellae on the N. F. Bd. 2, Ht. 3, pp. 188-189, pl. 8, area. figs. 5 and 5a. Distribution.-Upper jurassic to Upper 1923. Trigonia sawatai YEHARA, Japan. Jour. Cretaceous; Northern Pacific region. Ceol. Ceogr., vol. 3, p. 80, pl. 10, fig. 9. 1954. Heterotrigonia sawatai (YEHARA): Ko­ BAYASHI, Japan. Jour. Ceol. Ceogr., Subgenus Heterotrigonia Cox, 1952 vol. 25, nos. 1-2, p. 77. 1957. Apiotrigonia jimboi NAKANO, Japan. Type-species: Trigonia diversicostata Jour. Ceol. Ceogr., vol. 28, nos. 1-3, WHITEAVES, 1876. p. 115, pI. 8, figs. 5-7. Diagnosis.-Shell pyriform, umbo pro­ 1957. Heterotrigonia subovalis (lIMBO) : NAKA­ minent, opisthogyrous; disk ornamented NO, Japan. Jour. Ceol. Ceogr., vol. 28, with two series of costae; anterior ones nos. 1-3, p. 118, pI. 8, figs. 13-15. plain, concentric near the umbo, but 1961. Heterotrigonia subovalis (lIMBO) : NAKA­ NO, .Trans. Proc. Palaeont. Soc. Japan, horizontal, oblique, waved or obsolete on N. S., no. 42, p. 57, pl. 9, figs. 1-14. the antero-ventral part, occupying about ?1960. Megatrigonia (Apiotrigonia) subovalis the anterior half or less of the disk; (lIMBO): LIVEROVSKAJA, Palaeont. posterior costae plain, occupying the Bull., 2, Leningrad, pp. 251-252, pI. 5, posterior half or so of the disk; area figs. 1-3. ornamented with plain radial costellae; 1975. Apiotrigonia (Heterotrigonia) subovalis escutcheon narrow,smooth or ornamented (lIMBO): HAYAMI, Univ. Mus., Univ. with oblique or subhorizontal costellae; Tokyo, Bull. no. 10, p. 115. postero-ventral and escutcheon carinae indistinct except near the umbo. Material.-KSG 2125-2128, external and Remarks.-Three species, e. g., Trigonia internal moulds from Keirinbashi of diversicostata WHITEAVES, from the Shimo - Katsurazawa, Mikasa City, Albian of British Columbia, Trigonia Hokkaido; KSG 2129-2130 from the calderoni (CASTILLO and AGUILERA), Ponbetsu River (Loc. near Ik 2016), from the Upper jurassic of Mexico and Mikasa City, Hokkaido; GK. H6051 and Texas, and Trigonia subovalis JIMBO, 6055, collected at Ik 2021, on the Pon­ from the Cenomanian of japan, are betsu River, by T. MATSUMOTO. referable to this subgenus. It resembles Description.-Shell large, pyriform, closely Apiotrigonia s. str. in its orna­ moderately inflated, longer than high; mentations of the disk and the escutcheon, test rather thick; umbo slightly pro­ and its pyriform outline of the valve. minent, located at about one third or one Unless the area is observable, it may be fourth of length from the front of the difficult to discriminate Heterotrigonia s. valve; anterior margin well rounded; str.. from Apiotrigonia s. str. ventral margin moderately arched; Distribution.-Upper jurassic and siphonal margin weakly rounded or Cretaceous; Northern Pacific region, somewhat truncated obliquely, slightly Central America (Mexico and Texas). rostrate; posterior dorsal margin weakly concave; disk ornamented with two Heterotrigonia (Heterotrigonia) series of costae: anterior ones plain, subovalis (jIMBO) generally weak, of which several on the umbonal region are concentric, those on Plate 26, Figs. 23-24, Text-fig. 12 the anterior ventral part nearly obsolete, 709. Pennatae trigoniids from Japan 209

Text-fig. 12. Diagramatic sketches showing two shapes of Heterotrigonia (Hetero­ trigonia) subovalis (JIMBO). A: radiate form (form of Trigonia sawatai) , B: typical form, scale 5 mm.

and those on the median part generally Remarks.-This species was described subhorizontal, variable in the arrange­ in detail by NAKANO (1957, 1961). It is ment, oblique, wavy and sometimes dis­ variable in the features of the surface appear; the costae of posterior series ornamentation. Trigonia sawatai YEHARA, subradial, generally weak, broadly 1923, and Apiotrigonia jimboi NAKANO, spaced, numbering about 10 or more, of 1957, are here regarded as synonyms of which 2 or so near the umbo do not Heterotrigonia (Heterotrigonia) subovalis. reach the ventral margin and the next However, two forms are represented in 2 or so are very often bi- or trifurcated the same fossil population of this species. near the ventral margin; area ornamented Radiate form (form of T. sawatai):­ with radial costellae which are very Subradial costae of the posterior series variable in number and strength and appear distinctly under the umbo; sometimes effaced; escutcheon depressed, anterior series irregularly waved on. the narrow, ornamented with fine and plain anterior ventral part; radial costellae on horizontal or oblique costellae; escutcheon the area numerous and distinct. carina indistinct; posterior carina "Typical form": - Subradial costae distinct near the umbo but later weak, less numerous than in the radiate changing into roundly elevated and form; costae of the anterior series nearly concave ridge; median groove on the disappear on the anterior ventral part; area very shallow. radial costellae on the area very weak and discernible only on the umbonal Measurements (in mm).- region; umbonal angle somewhat broader Specimen Length Height Thickness than in the radiate form. KSG 2127, right ex. 32.0 24.1 8.4 This species differs from Heterotrigonia mould (Heterotrigonia) calderoni (CASTILLO and GK. H6051 AGUILERA) from the Upper Jurassic of left valve 43.2 33.3 10.8 GK. H6055, Mexico and Texas, and H. (H.) diversi­ right valve 48.9 38.2 12.0 costata (WHITE AYES) from the Albian of British Columbia, in its distinct costellae on the escutcheon. Two imperfect speci- 210 Masayuki TASHIRO Aiotrpigonia (Apiotrigonia) mikasaensis Z nov. of the same locality in its less "'TJ :::0 numerous costae on the disk. lj> Occurrence.-Sandstone of the Mikasa rli Formation at Keirinbashi of Shimo­ -l 0 katsurazawa, Ikushunbetsu, and on the z Pombetsu River (Ik 2021), both in Mikasa, Central Hokkaido; Middle Cenomanian. ?Sandstone of the upper part of the C Mikasa Formation of Ponbetsu (Ik 2016) ; z :::0 « l> Turonian. Sandstone of the upper part z (lId) of the same formation at an o A l> abandoned quarry, NWW of the Katsura­ ~ zawa-dam, Ikushunbetsu; Turonian. z Subgenus Nakanotrigonia nov. B z~ Type-species: Heterotrigonia himeno­ 8 urensis TASHIRO, 1972; Lower Campanian. Diagnosis. -Shell small, trigonal-ovate, Z G"I a little longer than high; umbo small, costae; the plain, concentric ones on ::l A I- umbonal part and subradial, tuberculated l> ones extending to the outer part of the :i o z outskirt of the umbonal concentric ones; a:i area rather broad, ornamented with u A several tuberculate radial costellae; «z escutcheon very narrow, with numerous in tuberculate, oblique costellae; escutcheon --l

1972. Heterotrigonia himenourensis TASHIRO, Trans. Proc. Palaeont. Soc. Japan, N. S., Genus Columbitrigonia PauL TON, 1977 . no. 86, p. 334, pI. 41, figs. 14-16, text·fig. 8. 1975. Apiotrigonia (Heterotrigonia) himeno· Type-species: Trigonia columbiana urensis (TASHIRO): HAYAMI, Univ. PACKARD, 1921. Mus., Univ. Tokyo, Bull. no. 10, p. 116. Remarks.-This genus is characterized Description and lvIeasurements.-(see by well developed subradial costae of TASHIRO, 1972). the posterior series. In young stage it Remarks.-This species differs from shows the surface ornamentations of Heterotrigonia (Nakanotrigonia) granosa typical Apiotrigonia. PauL TON (1977) NAKANO in its distinct postero-ventral referred it to Megatrigoniinae VAN carina, well developed subradial costae HOEPEN, together with Apiotrigonia. of the posterior series, and bi- or trifur­ Age and distribution. - Albian, south­ cate subradial costae on the antero­ western British Columbia. ventral part of the disk. Occurrence.-Black siltstone of the ?Genus Quoiecchia CRICKMA Y, 1932 Upper Formation of the Lower Himeno­ ura Subgroup (Formation L-III) at Type-species: Quoiecchia aliciae CRICK­ Okoshiki and Hiraiwa beaches of Oda, MAY, 1932. Uto City, Kumamoto Pref. (Uto Penin­ Remarks.-This genus is debatable as sula); lower Lower Campanian; Lowest to its taxonomic position. It was Hetonaian. referred to the Laevitrigoniinae by SAVELIEV (1958), but to the Myophorel­ Heterotrigonia (Nakanotrigonia) linae by PauL TON (1977). It is charac­ granosa NAKANO terized by subvertical or subradial costae on the posterior part of the disk where 1957. Heterotrigonia granosa NAKANO, Japan. the costae extend from the postero­ Jour. Ceol. Ceogr., vol. 28, nos. 1-3, ventral ridge to the ventral margin. p. 119, pI. 8, fig. 16. Its costae resemble more closely to those 1975. Apiotrigonia (Heterotrigonia) granosa of the posterior series of Apiotrigonia (NAKANO) : HAYAMI, Univ. Mus., Univ. Tokyo, Bull. no. 10, p. 116. s. str. or Heterotrigonia s. str. than the costation of lvIyophorella and Laevitri­ Remarks.-This species resembles Apio­ gonia. Its less opisthogyrate umbo and trigonia (lvIicrotrigonia) amanoi (N AKA- less angulated postero-ventral ridge are 212 Masay'/!-ki TASHIRO also similar to those of the pennatae concentric costae on· the umbonal part. trigoniids .. Such a costation on the disk is one of Age and distribution.-Lower Creta­ the important characters of pennatae ceous, British Columbia. trig()niids.. The anterior subhorizontal costae. (anterior series) meet with the posterior subra·dial op.~~ (posterior series) Evolutionary changes of the usually on the central part of the disk, subfamily Apiotrigoniinae forming the reversed L sculptures. As illustrated by STOY ANOW (1949, pI. 14, The earliest species of pennatae figs. 1 and 2), the umbonal region of trigoniids is represented by Trigonia T. calderoni is characterized by Fren­ calderoni (CASTILLO and AGUILERA) guelliella- or Rutitrigonia-like regularly (CRAGIN, 1905; STOY ANOW, 1949; SKW AR­ spaced and plain concentric costae. Such KO, 1970), from the Upper Jurassic of a Frenguelliella- or Rutitrigonia-like Mexico and Texas. T. calderoni is charac­ stage is generally observable on the terized by its smooth escutcheon and umbonal region of numerous species in finely radiating area as mentioned by pennatae trigoniids, as has already been SKWARKO (1970) and NAKANO (1971). mentioned by TASHIRO (1972). T. calderoni, The disk of T. calderoni is ornamented is probably a common ancestor of many with subhorizontal plain costae on the species belonging to Apiotrigonia s. I. anterior part, subradial or subvertical and Heterotrigonia s.l., which flourished costae on the posterior, and fine regular extensively in the Cretaceous period.

Species cenom.Tur·leon·lsanton. I Campanian IMaestricht.

Het. (Het.) subova/is Hel.(Nok.) granosa - Het. (Nak.) himenourensis -- Ap: (Ap,) mikasaensis Ap. (Ap.) minor Ap. (Ap.) crassoradiota Ap. (Ap.) hetonaiano Ap. (Ap.) undu/osa ---x Ap. (Ap.) utoensis X Ap. (Ap.) obso/eto -- Ap. (lAp.) dubia Ap. (Micr.) imufensis Ap. (Micr.) amanoi -- Ap. (Mlcr.) posfonodosa .--.. Ap. (Micr.) minima x Ap. (Micr.) sp. x

Gvliakian I Urakawah I Hetonaian

Text-fig. 14. The stratigraphic ranges of the pennatae trigoniid species from Japan. 709. Pennatae trigoniids from Japan 213 Heterotrigonia is known from the characterized by numerous radial costellae Cenomanian and Turonian (Gyliakian) of on the area. T. subovalis is very change­ Hokkaido in Japan. It is represented by able in the number and strength of the Trigonia subovalis JIMBO (1894), which is costae and costellae. The subradial

Text-fig. 15. Map showing the distributions of the pennatae trigoniids in the world.

/ Microf'rigonlo

Aplofrigonlo

Heferofrlgonio

UP. JUR. LOWER CRETACEOUS UPPER CRETACEOUS

Text-fig. 16. Possible lines of descent of the pennatae trigoniids. 214 Masayuki TASHIRO costae are weakened or bi- or trifurcate part of the disk. Dampietrigonia was on the ventral part, and the subhorizontal probably derived from Trigonia calderoni costae are weakened, irregularly waved or some other pennatae trigoniids in the or sometimes disappearing in the mature Early Cretaceous. The close relationship or late aged specimens. Heterotrigonia between T. calderoni and Dampietrigonia s. str. began to appear, probably in the is shown by their smooth escutcheon Upper Jurassic, as shown by the occur­ and somewhat truncated siphonal margin. rence of Trigonia calderoni in Central Apiotrigonia s. str. is the most flourished America, and disappeared in the Middle group in the pennatae trigoniids (Apio­ Turonian (K4b2 by MATSUMOTO, 1977) trigoniinae), characterized by the absence of Japan, with the downfall of Trigonia of radiating costellae on the area. The subovalis. The distribution of Heterotri­ earlier representatives of Apiotrigonia gonia was shifted from Central America are several species from the Lower to Japan along the North Pacific Coast, Cretaceous of Central America and South passing through British Columbia, where America (STOY ANOW 1949, ANDERSON Heterotrigonia diversicostata and radiat­ 1938, STANTON 1901). The latest one is ing "Trigonia newcombei" (NAKANO, 1961, represented by Apiotrigonia (Apiotrigonia) 1971), are known. hetonaiana, from the Maastrichtian (K6bl) Heterotrigonia s. str. is undoubtedly of Japan. Some species of Apiotrigonia succeeded by Nakanotrigonia nov., which s. str. from the Lower Cretaceous, are occurs in the Santonian and Lower generally characterized by the regularly Campanian (K5b and K6al) of Japan. arranged costae of the anterior series Nakanotrigonia is characterized by tuber­ and the escutcheon without costellae. culate radial costellae on the area and On the other hand, the species of APio­ tuberculate subradial costae which trigonia s. str. from the Upper Cretaceous occupy nearly the whole surface of the are characterized by the variable arrange­ disk except for the narrow umbonal ment of the anterior series and the part, crossing to plain concentric costae. costellate escutcheon. The Campanian Nakanotrigonia is probably a branch and Maastrichtian species, such as A. which offshooted from the Heterotrigonia (A.) hetonaiana and A. (A.) crassoradiata, trunk represented by the successive species probably represent the last phase of the from T. calderoni to T. subovalis by way of evolutionary trend in the main trunk of T. diversicostata and "T. newcombei", as Apiotrigonia s. str., as shown by their has already been pointed out by NAKANO extraordinarily bi- or trifurcate subradial (1961, 1971). Text-fig. 13 diagramatically costae of the posterior series and the illustrates the three species of Heterotri­ irregularly waved or effaced costae of gonia s. I. from Japan, showing the the anterior series. Similar features are successive change with age. Also text­ also observable in H. (H.) subovalis, the fig. 12 shows two varied forms of latest species of Heterotrigonia s. str. Heterotrigonia (Heterotrigonia) subovalis. On the other hand, the earlier species of Dampietrigonia nov., based on 'Apoitri­ Heterotrigonia, e. g., H. (H.) calderoni gonia' dampierensis SKW ARKO (1969) from and H. (H.) diversicostata, are similar to the Aptian of Western Australia, is the earlier ones of Apiotrigonia s. str. characterized by the smooth area and of the Lower Cretaceous, e. g., A. (A.) escutcheon, and numerous subradial cragini, A. (A.) kitchini and A. (A.) costae which invade into the anterior kayana from North America, and A. CA.) 709. Pennatae trigoniids from Japan 215

UP. JURASSIC LOW. CRETACEOUS UPPER CRETACEOUS

Text-fig. 17. Diagram showing the directionally increasing radial ornaments on the disk of the pennatae trigoniids and the evolutional parallelism between trunks of Hetero- r_ 0 trigonia and Apiotrigonia. A: Heterotrigonia (Heterotrigonia) calderoni; B: H. (H.) diver­ sicostata; C: H. (H.) subovalis; D: H. (Nakanotrigonia) himenourensis; E: Quoiecchia aliciae; F: Apiotrigonia (Apiotrigonia) pennata; G: A. (A.) mikasaensis; H: A. (A.) crassoradiata; I: A. (A.) hetonaiana; J: A. (Microtrigonia) amanoi; K: A. (Dampietri­ gonia) dampierensis; L: Columbitrigonia columbiana; M: A. (Turkestanella) turllestanensis; N: A. (A.) obsoleta.

newcombei and A. (A.) condoni from along the North Pacific coast. The British Columbia, in their regularly second route was from Central America arranged costae of the both series on the to Central Asia (Turkestan), passing disk. These similarities in successive Texas, England and France, along the changes with geological age imply the northern coast of the Tethys Sea. The evolutionary parallelism between Apiotri­ third one was presumably from the gonia and Heterotrigonia. native home to western Australia passing In sofar as I know, the origin of through South America and South Africa, Apiotrigonia s. str. was probably in the along the South western Pacific coast. Lower Cretaceous of Central America, This is suggested by the subgenus as that of Heterotrigonia s. str. Apiotri­ Dampietrigonia from Australia by way gonia s.1. expanded its distribution into of A. (A.) heterosculpta STANTON, 1909) three directions. One was the same as from Patagonia, A. CA.) progonos (PAU­ in the case of Heterotrigonia s. str., ex­ LCKE) (REYES and PEREZ, 1978) from tending from Central America to Japan Chile and A. (A.) concardiformis (KRAUSS) 216 Masayuki TASHIRO from South Africa (KITCHIN 1913). Microtrigonia NAKANO, 1957, from CoLumbitrigonia POULTON (1977), from Japan, is undoubtedly derived from Apio­ the Lower Cretaceous (Barremian to trigonia s. str., with Apiotrigonia (APio­ Albian) of British Columbia, is charac­ trigonia) utoensis as its presumable terized by extraordinarily developed ancestor. Microtrigonia closely resembles subradial costae of the posterior series. Nakanotrigonia and TurkestaneLLa in the It is undoubtedly derived from Apiotri­ ornamentation of the disk, but differs gonia s. str., because the immature shell from Nakanotrigonia in its less developed has distinctly the Apiotrigonia-type costae radial costellae on the area, and from as illustrated by POULTON (1977, pi. 2, TurkestaneLLa in its more numerous costae figs. 22, 24, 28, 29, 30, 33, 38, 41, 42 and of the posterior and anterior series. 43 ; pi. 3, figs. 22 and 23). CoLumbitrigonia Microtrigonia is the latest branch from probably offshooted from the Apiotrigonia the Apiotrigonia trunk, as Nakanotrigonia trunk in an early Cretaceous time. is so from the Heterotrigonia trunk. Quoiecchia CRICKMAY (1932), from the Microtrigonia appears, however, later Lower Cretaceous of British Columbia, than Nakanotrigonia (Microtrigonia in the is doubtful in the systematic position. Lower Campanian as compared with For the reasons which I mentioned in p. Nakanotrigonia in the Santonian) (see 212, I regard it as a member of the Text-figs. 16, 18). pennatae trigoniids (Apiotri:goniinae), TurkestaneLLa, from the Cenomanian of presumably a branch from the Hetero­ Turkestan, may also be a derivative from trigonia trunk. the Apiotrigonia trunk.

Text-fig. 18. Presumed phylogenetic relations in the subfamily Apiotrigoniinae nov. T: Trigoniinae, B: Apiotrigoniinae, R: Rutitrigoniinae and Megatrigoiinae; A: Apiotrigonia trunk, H: Heterotrigonia trunk. 709. Pennatae trigoniids from Japan 217

The Apiotrigonia trunk ranges from 66, no. 783, p. 769-779. the lowest Cretaceous to the uppermost -- (1962): The geologic history of the Cretaceous, accompanied with several Paleo·Shiranui Bay in the Neo·Cretaceous branches, e. g., Columbitrigonia in the period (Part 2, Regional geology). Neocomian, Dampietrigonia in the Aptian, Kumamoto Jour. Sci., ser. B, sec. 1, Geol., vol. 5, no. 1, p. 1-36. Turkestanella in the Cenomanian and -- (1963): Geology of Ikara·jima, Izumi· Microtrigonia in the Campanian. The gun, Kagoshima Prefecture. Ibid., vol. 6, Heterotrigonia trunk probably ranges no. 1, p. 12-17. from the Upper Jurassic to the lower ANDERSON, F. N. (1938): Lower Cretaceous Lower Campanian, accompanied with the deposits in California and Oregon. Ceol. branches of Quoiecchia(?) in the Lower Soc. America, Sp. Pap., no. 16, p. 1-339, Cretaceous and Nakanotrigonia in the pis. 1-48. Santonian (see Text-fig. 18). ARCHANGELSKI, A. D. (1916): Les mollusques In my opinion, the phylogenetic du Cretace superieur du Turkestan. Mhn. evolution ·of the pennatae trigoniids Com. Ceoi. Petrograd, N. Ser. Livr. 152, 52 p., 8 pis. (Apiotrigoniinae) probably took place Cox, L. R. (1952): Notes on the Trigoniidae, systematically in a definite direction with outline of a classification of the which is manifested by the development family. Proc. Mal. Soc. London, vol. 29, or increase of the subradial costae, the pts. 2 and 3, p. 45-70, pis. 3-4. so-called posterior series, and the degene­ CRAGIN, F. R. (1905): Palaeontology of the ration of the concentric or subhorizontal Malone Jurassic Formation of Texas. costae, the so-called anterior series (see Bull. United States Ceoi. Surv., no. 266, Text-fig. 17). The directional evolution ser. C, no. 73, p. 1-172. proceeded on the trunks of Apiotrigonia CRICK:VIAY, C. H. (1932): Contribution toward and Heterotrigonia in parallel with each a monograph of the Trigoniidae. American other, and also in several branches which Jour. Sci., vol. 24, p. 443-464. offshooted from the both trunks. The GEINITZ, H. B. (1872-73): Das Elbthalgebirge in Sachsen. 1, Der untere Quader. 5, evolutional tempo in each branch or Brachiopoden und Pelecypod en. Palaeon­ trunk was not constant. tographica, vol. 20, pt. L HAGG, R. (1954): Die Mollusken und Bra· References chiopoden der Schadischen Kreide 4, Sver. Ceol. Unders., ser. C, no. 535, 72 p., 9 AGASSIZ, L. (1840): Etudes critiques sur les pis. Mollusques Fossiles, Memoire sur les HATAE, N. (1959): On the stratigraphical Trigonies, 58 p., 11 pis., (Neuchatel). boundary between the Upper Cretaceous AMANa, M. (1957): Upper Cretaceous mol­ and Palaeogene strata of Amakusa· luscan fossils from Shimo-Koshikijima, Shimoshima, Kumamoto Prefecture. Sci. Kyushu. Kumamoto Jour. Sci., ser. B, Rep. Kagoshima Univ., no. 8, p. 102-113 sec. 1, Geol., vol. 2, no. 1, p. 63-86, pis. (in Japanese). 1-2. -- (1960): The geology and the geological -- (1960a): Geology of Tobase-jima and structure of Amakusa·Shimoshima, Kuma· Senzokuzozo·jima, Amakusa, Kumamoto moto Prefecture. Ibid., no. 9, p. 61-107 Prefecture. Ibid., vol. 4, no. 1, p. 1-12, (in Japanese). pI. L HAYAMI, I. (1968): Some Jurassic bivalves -- (1960b): Geology of Maki·shima and its from Mindoro. Ceoi. Palaeont. South. neighboring islands, Amakusa, Kumamoto east Asia, vol. 5, p. 173-185, pis. 21-22. Prefecture. Jour. Ceol. Soc. Japan, vol. -- (1975) : A systematic survey of the 218 Masayuki TASHIRO

Mesozoic Bivalvia from Japan. Univ. of the Upper Cretaceous in Japan. Mid­ Mus., Univ. Tokyo, Bull. no. 10, p. 1-228, Cretaceous Events, Hokkaido Symposium, pis. 1-10. 1976. Palaeont. Soc. Japan, Sp. Pap., JIMBO, K. (1894): Beitrage zur Kenntnis der no. 21, p. 63-74. Fauna der Kreideformation von Hokkai­ -- and HARADA, M. (1964): Cretaceous do. Palaeont. Abhandl. N.F., vol. 2, no. stratigraphy of the Yubari dome, Hokkai­ 3, p. 149-194, pis. 17-25. do. Mem. Fac. Sci., Kyushu Univ., ser. JONES, D. L. (1960): Lower Cretaceous D, vol. 15, no. 1, p. 79-115, pis. 9-11. (Albian) fossils from South-Western MIKI, T. (1972): Cretaceous-Tertiary uncon­ Oregon and their paleogeographic signi­ formity in the western part of Amakusa ficance. Jour. Palaeont., vol. 34, no. 1, Shimoshima. Ibid., vol. 21, no. 2, p. 217- p. 152-160, pI. 29. 237, 2 pis. KOBAYASHI, T. (1954): Studies on the NAGAO, T. (1930): On some Cretaceous Jurassic trigonians in Japan. Part 1, fossils from island of Amakusa, Kyushu, Preliminary notes. Japan. Jour. Geol. Japan. Jour. Fac. Sci., Hokkaido Imp. Geogr., vol. 25, nos. 1-2, p. 61-80. Univ., ser. 4, vol. 1, no. 1, p. 1-25, pis. -- (1956): Studies on the Jurassic trigoni­ 1-3. ans in Japan, part 5, Some Jurassic -- and OTATUME, K. (1938): Molluscan trigonians from central and west Japan. fossils of the Hakobuchi Sandstone of Ibid., vol. 27, no. 1, p. 1-8, pI. 1. Hokkaido. Ibid., vol. 4, nos. 1-2, p. 31- -- (1957) : A trigon ian faunule from Mindoro 56, pis. 1-4. in the Philippine islands. Jour. Fac. Sci. NAKANO, M. (1957): On the Cretaceous Univ. Tokyo, sec. 2, vol. 10, no. 3, p. pennatae trigonians in Japan. Japan. 351-365, pI. 3. Jour. Geol. Geogr., vol. 28, nos. 1-3, p. KITCHIN, F. L. (1913): The invertebrate 107-120, pis. 8-9. fauna and palaeontological relations of -- (1960): Stratigraphic occurences of the the Uitenhage series. South African Cretaceous trigoniids in Japanese Islands Mus., Ann., vol. 7, pt. 2, no. 3, p. 21-250, and their faunal significances. Jour. Sci. pis. 2-11. Hiroshima Univ., ser. C, vol. 3, p. 215-280. LEANZA, A. F. (1942): Los Pelecipodos del -- (1961a): On the Trigoniinae. Ibid., Lias de Piedra Pintada en el Neuquen. ser. C,vol. 4, p. 71-94. Rev. Mus. de la Plata, N.S. tom. 2, p. -- (1961b): Note on Heterotrigonia sub­ 143-206, pis. 1-19. ovalis (lIMBO). Trans. Proc. Palaeont. LEBKUCHNER, R. (1933): Die Trigonien des Soc. Japan, N. S., no. 42, p. 55-62, pI. 9. siiddeutschen Jura. Palaeontographica, -- (1963): On the Rutitrigoniinae. Geol. vol. 77, p. 1-119, pis. 1-16. Rep. Hiroshima Univ., no. 12, p. 513-529, LIWEROWSKAJA, E. V. (1960): Stratigraphy pI. 56. and fauna of the Upper Cretaceous for­ -- (1971): A note on Trigonia calderoni mation in the East Coast of Penshina (CASTILLO and AGUILERA). Res. Bull. Bay. Palaeont. Bull., 2, Leningrad, p. Hiroshima Inst. Techn., vol. 6, no. 1, p. 231-261, pis. 1-6. 11-13. LYCETT, J. (1872-79): A Monograph of the NEWELL, N. D. and BOYD, D.W. (1975): British Fossil Trigoniae. Palaeontogra­ Parallel evolution in early trigoniacean phical Soc., 245 p., 41 pis., London. Bivalves. Bull. American Mus. Nat. MAEDA, S. and KAWABE, T. (1967): Apio­ Hist., vol. 154, art. 2, p. 55-162. trigonia from the Futaba Group in the PACKARD, E. L. (1921): The Trigoniae from Joban District, North Japan. Prof. H. the Pacific Coast of North America. SHIBATA Memorial Volume, p. 420-425, Univ. Oregon Publ., vol. 1, no. 9, p. 3-35, pI. 1, table 1. pis. 1-11. MATSUMOTO, T. (1977): Zonal correlation POJARKOVA, Z.N. (1978): Upper Cretaceous 709. Pennatae trigoniids from Japan 219

bivalve mollusca from north Vostochnoj from the Himenoura Group, Kyushu, Japan. Area, Central Asia. Akademiia Nauk Trans. Proc. Palaeont. Soc. Japan, N.S., Kirgizskoj CCP, p. 1-143, pis. 1-65. no. 86, p. 325-339, pis. 40-41. POUL TON, T. P. (1977): Early Cretaceous -- (1976): Bivalve faunas of the Cretace­ trigoniid bivalves of Manning Provincial ous Himenoura Group in Kyushu. Palae­ Park, Southwestern British Columbia. onto Soc. Japan, Sp. Pap., no. 19, 102 p., Geol. Surv. Canada, Pap. 76-9, 25 p., 3 12 pis. pis. -- (1978): New species of Apiotrigonia REYEs, R. B. and PEREz, E. D' A. (1978): and Senis from the uppermost Cretaceous Las trigonias del Titoniano y Cretacico of Hokkaido. Trans. Proc. Palaeont. inferior de la cuenca Andina de Chile. Soc. Japan, N.S., no. 112, p. 424-433, pI. Inst. Invest. Geol. Chile, Bol. 32, 105 p., 54. 5 pis. -- and NODA, M. (1973): The geological SAITO, T. (1962): The Upper Cretaceous age of the "Himenoura Group", Kyushu, System of Ibaraki and Fukushima Pre­ Japan. Jour. Geol. Soc. Japan, vol. 79, fecture, Japan (Part 2). Bull. Fac. Arts no. 7, p. 465-480, pI. 1 (in Japanese). and Sci., Ibaraki Univ., Nat. Sci., no. 13, -- and OTSUKA, M. (1976): Inoceramus p. 52-87, 8 pis. from Hayaura in Ushibuka City, Kuma­ SAVELIEV, A. A. (1958): Lower Cretaceous moto Prefecture. Ibid., vol. 82, no. 2, p. trigoniids of Mangyschlak and western 139-141 (in Japanese). Turkmenia. Trudy Vnigri, no. 125, 516 -- and -- (1978): Stratigraphical study p., 58 pis. on the boundary between the Upper SKW ARKO, S. K. (1963): Australian Mesozoic Cretaceous and Paleogene strata of trigoniids. Bur. Min. Res., Geol., Geo­ Amakusa-Shimojima Island, Kumamoto phys., Australia, Bull. 67, p. 1-55, 6 pis. Prefecture, Kyushu. Res. Rep. Kochi -- (1969): Aptian (Lower Cretaceous) Univ., vol. 27., no. 9, p. 113-134, 2 pis. 'Apiotrigonia' from the Melligo Quartzite (in Japanese). Dampier Peninsula, Western Australia. TERAOKA, Y. (1970): Cretaceous formations Bur. Min. Res., Geol. Geophys., Canberra, in the Onogawa basin and its vicinity, p. 227-234, pI. 33. Kyushu, southwest Japan. Geol. Surv. -- (1970) : An Upper Jurassic Apiotrigonia Japan, Rep., no. 237, p. 1-84, pis. 1-18. from Mexico. Bol. Soc. Geol. Mexicana, UEDA, Y. (1962): The type Himenoura vol. 31, no. 2, p. 75-78, pI. 1. Group. With palaeontological notes by STANTON, T. W. (1901): The marine Cretace­ MATSUMOTO, T. and UEDA, Y., Mem. ous invertebrates. Princeton Univ. ex­ Fac. Sci., Kyushu Univ., vol. 12, no. 2, pediteons to Patagonia, 1896-1899, Repts., p. 129-178, pis. 22-27. Vol. 4, Paleontology, Pt. 1, 43 p., 10 pis. -- and FURUKAWA, N. (1960): On the STOY ANOW, A. (1949): Lower Cretaceous Himenoura Group of the Amakusa-Kami­ stratigraphy in Southeastern Arizona. shima and adjacent islets, Kumamoto Geol. Soc. America, Mem. 38, 136 p., 26 Prefecture. Sci. Rept., Kyushu Univ., pis. Geol., vol. 5, no. 1, p. 35-44 (in Japanese). TANAKA, K. and TERAOKA, Y. (1973): v AN HOEPEN, E. C. N. (1929): Die Krytfauna Stratigraphy and sedimentation of the von Soeloeland, I. Trigoniidae; Pal. Upper Cretaceous Himenoura Group in Navorsing Nat. Mus. Bloemfontein, vol. Koshiki-jima, Southwest Kyushu, Japan. 1, pt. 1, 38 p., 7 pis. Bull. Geol. Surv. Japan, vol. 24, p. 157- WHITEAVES, J. F. (1876): On some inverte­ 184, pis. 15-24 (in Japanese). brates from the coalbearing rocks of the TASHIRO, M. (1972): On the surface orna­ Queen Charlotte Island. Geol. Surv. mentation of the pennatae trigoniids, and Canada., Mesozoic Fossils, Vol. 1, 92 p., on three new species of the trigoniids 10 pis. 220 Masayuki TASHIRO

Y ABE, H. (1927): Cretaceous stratigraphy Prefecture. Sci. Rept_, Kyushu Univ., of the japanese islands. Sci. Rep. Tohoku Geol., vol. 11, no. 1, p. 35-44 (in Imp. Univ., ser. 2, vol. 11, no. 1, p. 27- japanese) . 100, pis. 3-9. YEHARA, S. (1915): The Cretaceous trigoniae -- and NAGAO, T. (1925): New or little from Miyako and Hokkaido. Sci. Rept. known Cretaceous fossils from north Tohoku Imp. Univ., ser. 2, vol. 2, no. 2, Saghalin. Ibid., ser. 2, vol. 7, no. 4, p. p. 35-44, pis. 1-2. 111-124, pis. 28-29. (1923): Cretaceous trigoniae from YAMAMOTO, S. and HAY AMI, I. (1971): Cre­ southwest japan. Japan. Jour. Ceol. taceous system of Shishijima, Kagoshima Ceogr., vol. 2, no. 3, p. 59-84, pis. 8-13.

Explanation of Plate 25

Apiotrigonia (Apiotrigonia) mikasaensis sp. nov. Fig. 1: GK. H6910; right valve, xl; loco Yonnosawa, Ponporokabetsu, Yubari, Hokkaido. Fig. 2: GK. H6912; left valve, xl; loco ditto. Fig. 3: GK. H6913; left valve, xl; loco ditto. Fig. 4: GK. H6911; left and right valves, xl; loco ditto. Fig. 5: KSG 2061; right valve, x 1.2; loco Ponbetsu, Mikasa City, Hokkaido. Fig. 6: KSG 2070; a cluster of specimens, xl; loco ditto. Apiotrigonia (Apiotrigonia) undulosa NAKANO Fig. 7: KSG 2064; gum cast of left external mould, x 2; loco Kajisako of Monobe, Kochi Pref., Shikoku. Fig. 8: KSG 2065; gum cast of left external mould, x 2; loco ditto. Fig. 9: KSG 2073; gum cast of left external mould, x 3; loco Hiromi, Uwajima City, Ehime Pref., Shikoku. Fig. 10: KSG 2074; gum cast of left external mould, x 2; loco ditto. Apiotrigonia (?Apiotrigonia) duMa sp. nov. Fig. 11: KSG 2087; gum cast of left external mould, x5; loco Azenotani, Sakai City, Izumi Mountains. Fig. 12: KSG 2088; gum cast of right external mould, x 2.5; loco ditto. Fig. 13: KE 1935; gum cast of left external mould, x 2; loco ditto. Fig. 14: KE 1936; gum cast of left external mould, x 2; loco ditto. Figs. 15, 16: KSG 2090; gum cast of left external mould, x 2; loco Masuno, Oniki-machi, Ushibuka City, Kumamoto Pref., Kyushu. Fig. 17: KSG 2091; gum cast of imperfect left external mould, x 5; loco ditto. Apiotrigonia (Apiotrigonia) minor (Y ABE and NAGAO) Fig. 18: KSG 2051; left valve, x 2; loco Wadanohana of Takado, Amakusa-Kamishima island, Kyushu. Fig. 19: KSG 2054; gum cast of right external mould, xI; loco Furushiroyama, Uwajima City, Ehime Pref., Shikoku. Fig. 20: KE 1906; left valve, x 2; loco Wadanohana of Takado, Amakusa·Kamishima island. Apiotrigonia (Apiotrigonia) crassoradiata NAKANO Fig. 21: KSG 2075; gum cast of right external mould, xI; loco Omagari of Tomiuchi (Heto­ nai), Iburi District, Hokkaido. Fig. 22: KSG 2085; gum cast of imperfect right external mould, xI; loco Fukkireura of Kashima, Shimo.koshikijima island, Kagoshima Pref., Kyushu. TASHIRO: Pennatae trigoniids from Japan Plate 25

5

6

2

3 4

8 7

10 18

20 17

11 15

...... 12 13 16

22 709. Pennatae trigoniids from Japan 221

Amakusa "Je1if., Amakusa-Kamishima "Je1if.J:,ill;, Amakusa-Shiimojima "Je1if.""f,ill;, Ashi- zawa JEtR, Awaji ~~, Azenotani ~/ i:l', Chinomigawa ~L;e:JII, Dogo }gf3€:, Fukaushi i?/i!lJ::, Fukkireura i!J.:-!iUillL Furushiroyama ~:lBtLlJ, Futaba ~jf, Futamado =FI39p, Goshonoura 1!llJmiflj, Hakobuchi ~lJl!~, Hanzanji ~LlJ~, Hetonai Jlt~P:!, Hidaka B i'i1ii, Himedo liCip, Himenoura liCiTili, Himezuka liCi~, Hinoshima 1lmz,ill;, Hiraiwa fE, Hiromi !A.m, Hirono !A!Ilf, Hongo *~, Iburi !lli.l1N, Ikushunbetsu ~*5JIJ, Imuta M.$[!, Inukai :;JdO], Iwaki 1'7 ,-\,-, Izumi ;f!l7'R, Kajisako ~{;£~, Kamihira J:f, Kashima J1g,ill;, Katsurazawa tttR, Kawaura VlJrilL Keirinbashi ?-1 V :/1\t, Keiji ~~, Kitaana ~tjr.JtJIl, Kita-uwa ~t~;f!l, Kugushima l1"],ill;, Masuno :tfM!Ilf, Mihara ?]Jj{. Mikasa =:~, Minato ~, Miyanokawachi '8!1lffoJlJ:] , Nodden ~[!, Oda ~83, Oe *iI, Okoshiki 1!llJ~*, Omagari *Ilt!, Oniki "'J~'-, Ono *!Ilf, On ogawa *!IlfJII, Onsen ifn\.jR, Otochi *tm, Oriki :W*, Oshima *,ill;, Panketosanosawa /{:/?- I- -It / tR, Ponbetsu ;f-:/"" '/ , Ponhorokabetsu ;f-:/ *' P 71"" '/ , Ryugadake ~?- ffi, Sakai JR, Saku {;£;Z, Sakuradani t2(i:l', Satsuma ifiJ!llf, Shichi 1.;%1, Shimokatsura ""ftt, Shimo-Koshiki Tt/[, Taikorin!; 1 ::z V :/, Takado i'i1iip, Takinoike iI'i!/ iU!, Teshionakagawa "JeJj[J:j:IJiI, Tomiuchi ffip:!, Ukimizu 1'J!.7lC, Ura- kawa TiliJil, Ushibuka lj::i?/i!, Uto ~±, Uwajima ~*1l,ill;, Wadanohana '1'!-1839,t, Yachi i:l':it!!, Yezo "'" ,/, Yokohama ~~, Yotsuinosako ~;Jf/ j§, Yonnosawa 11:9/ tR, Yuasa ~~, Yubari :9~.

B*.i£: "pennatae trigoniids" O)liJf~: *liJf~lt, *omO)J:'iffltn.lli*il'0%10;/1.G/H~!.

=: ~ ~ "pennatae trigoniids" t:.~-t G M1m~(fJ *jVE 7tM~i¥J liJf~ -c: l> G 0 * om -c: it "Pennatae Trigoniids" it, -I! / -< =- 7 :/--< A I- V 1::. -/7 :/t:.l±l:m. L, 16fj (2 ~fj) il~ lii~ ~;/1. Go .:.;/1.0It Heterotigonia c Apiotrigonia t:::.~-tGtO)ct:.:;J(5]Ij-C:~Go Heterotrigonia t:.~-t G t 0) It Heterotrigonia s. str. 0) 1 :ml c ~ill!J.m Nakanotrigonia 0) 2 fjO)llt 3 fjil~l> I), Heterotrigonia s. str. It-\! / -< =- 7 :/-7"- "- p =- 7 :/t:::.il,'! 0;/1.,

Nakanotrigonia It -It:/ I- =- 7 :/-71 :/ /{ =- 7 :/t:.i±',m-t G 0 Apiotrigonia t:.lt Apiotrigo­

nia s. str. c!!E~ Microtrigonia il~l> G 0 Apiotrigonia s. str. It 7"- "- p =- 7 :/--< A l­ V 1::. -/7 :/ i: "(,t:. 8 fj (2 ~fj) il~l> I), Microtrigonia It 71 :/ /{ =- 7 :/ J;J.~t:::. I±l:m. L, 7c

0) 5 fjil'~~ 0;/1. G 0 :;t - A I- '7 V7 O)Dampietrigonia (~!!EJm) -,?J:j:I:9 I) , 71 -r!;to) Columbitrigonia It:to7c 0 < Apiotrigonia s. str. c ~JiO)j'f;tJl~ t "? -C\" G c ,\~,tb;/1. G 0 i: t.: 71 -r !;t 0) Quoiecchia It Heterotrigonia t:.~Ji L t.:~lID'!iit!lli~f.fi?7c 0) * jVEi¥J~;i!IH1:il''f~ ~;/1.G 0 tJJ:O)Jm· !!E~~ t c t:'~!!E~;~ Apiotrigoniinae ~ID!:5E Lt.:o * ~.!lU4t:'lt Apiotrigonia trunk c Heterotrigonia trunk 0)=*7Uil~~~ 0;/1., lltr~'It :to7c 0 <""f'ifflS!!E*c.t:.:to\, '-Cf3€:~il' 07t;oz Lt.: c ,~,:b;h., i: t.:jj!ij~rl3't:'lt fIT Lt.:5EItiJi¥JtsJr~ mHfNtil'~~0;/1.Go *~ill!'fiHt, :to7c0 <~ "- '7*c.I3€:JtIlt:::. Frenguelliella il'l>G\"ltmW O)=:~A~JI§WJ(c L-cJ:j:l:9

It, Rutitrigoniinae c t '&i~tJ:~f*il~l> G c ,~,:b;h.G 0 83 ~ IE z 222 Masayuki T ASHI RO

Explanation of Plate 26

Apiotrigonia (Microtrigonia) amanoi (NAKANO) Fig. 1: KSG 2092; gum cast of left external mould, x 2.5; 'tuberculate form' ; loco Azenotani, Sakai City, Izumi Mountains. Fig. 2: same specimen, x 5. Fig. 3: KSG 2098; gum cast of right external mould, x 2; 'rostrate? form' ; loco Fukkireura of Kashima, Shimo-koshikijima island, Kagoshima Pref., Kyushu. Fig 4: KE 2130; gum cast of right external mould, x 2; 'typical form'; loco Ukimizu of Kashima, Shimo.koshikijima island, Kagoshima Pref., Kyushu. Fig. 5: KE 1934; gum cast of left external mould, x 2; 'typical form'; loco ditto. Kashima, Shimo.koshikijima island. Fig. 6: KSG 2097; gum cast of left external mould, x 2; 'typicai form'; loco Fukkireura of Kashima, Shimo·koshikijima island. Apiotrigonia (Microtrigonia) imutensis (TASHIRO) Fig. 7: KSG 2108; gum cast of left external mould, x 2; 'pseudo-utoensis form'; loco Oshima of Ushibuka City, Amakusa-Shimojima island, Kumamoto Pref., Kyushu. Fig. 8: KSG 2104; gum cast of left external mould, x 2; 'radiate form'; loco Fukkireura of Kashima, Shimo.koshikijima island. Fig. 9: KSG 2105; right valve, xl; 'radiate form'; loco ditto. Fig. 10: KSG 2107; plaster cast of left external mould, x 2; 'radiate form' ; loco Himezuka of Dogo, Matsuyama City, Ehime Pref., Shikoku. Fig. 11: KSG 2105; gum cast of right external mould, x 1.5; 'radiate form'; loco Yokohama of Oe, Amakusa·machi, Amakusa·Shimojima, Kumamoto Pref., Kyushu. Fig. 12: KSG 2106; gum cast of right external mould, x 2; 'radiate form' ; loco ditto. Apiotrigonia (Microtrigonia) postonodosa NAKANO Fig. 13: KSG 2117; gum cast of left external mould, x 1.5; loco Ono of Hongo, Miyanokawachi, Amakusa·Shimojima island, Kumamoto Pref., Kyushu. Fig. 14: KSG 2118; gum cast of right external mould, x 2; loco ditto. Fig. 15: KE 1927; gum cast of left external mould, x 2; loco ditto. Fig. 16: KSG 2116; gum cast of imperfect left external mould, x 2; loco Yotsuinosako of Kamihira, Miyanokawachi. Fig. 17: KSG 2115; gum cast of conjoined valves, x 1.5; showing the dorsal view; loco Ono of Hongo, Miyanokawachi. Apiotrigonia (Apiotrigonia) utoensis TASHIRO Fig. 18: KE 1882; right valve, xl; loco Okoshiki of Oda, Uto City (Uto peninsula), Kuma­ moto Pref., Kyushu. Apiotrigonia (Microtrigonia) sp. indet. Fig. 19: KSG 2120; right valve, x 2; loco Panketosanosawa of Tomiuchi (Hetonai), Iburi District, Hokkaido Fig. 20: KSG 2123; left internal mould, x 1.5.; loco ditto. Apiotrigonia (Dampietrigonia) dampierensis (SKWARKO) Fig. 21: CPC 7723; plaster cast of right external mould (see SK\YARKO, 1969). Fig. 22: CPC 7729; ditto. Heterotrigonia (Heterotrigonia) subovalis (lIMBO) Fig. 23: GK. H6056; left valve, xl; loco Shimokatsura, Mikasa (lK 2021), Hokkaido; collected by T. MATSUMOTO; 'typical form of subovalis'. Fig. 24: KSG 2125; plaster cast of imperfect left valve, xl; loco Keirinbashi, Shimokatsura, Mikasa, Hokkaido; 'radiate form' (form of Trigonia sawatai). Heterotrigonia (Nakanotrigonia) himenourensis TASHIRO Fig. 25: KSG 2131; left valve, x 2; loco Hiraiwa of Oda, Uto City, Kumamoto Pref., Kyushu. TASHIRO: Pennatae trigoniids from Japan Plate 26

3 4

S

6 2

8

9

. 13 :

...... 14 lS 16

17

19

20 23

2S

: Trans. Proc. Palaeont. Soc. Japan, N. S., No. 116, pp. 223-234, pis. 27, 28, December 30, 1979

710. SOME NEW BIVALVE SPECIES FROM THE LOWER GYEONGSANG GROUP, KOREA*

SEONG YOUNG YANG

Department of Earth Science, Kyungpook National University, Daegu 635, ,~or~~.

Abstract. Two new bivalvian species from the Yeonhwadong Formation, the lciw¢r­ most formation of the Gyeongsang Group are described here. ,Trigo7Jioides (Koreanaia) bongkyuni sp. nov. is ornamented with large angled V -shape subradial ribs of Koreanaia type and possesses fine crenulated hinge teeth of Wakinoa type. On account of the stratigraphic relation as well as the morphologic characters, T. (K;) bongkyuni is reasonably interpreted as a link-species between T. (K.) cheongi and some species of T. (Wakinoa) in the evolutionary lineage. The other new one" Pseudohyria matsumotoi, may be considered to be an ancestor of ,other specie,S of Pseudohyria reported from the continental side of Asia in respe~t of the strati­ graphic occurrences.

Introduction as'a derivative from Wakinoa observing the degree of the development of median Many species referred to the family cardinal teeth in the two :subgenera_ Trigonioididae have been reported from HAYAMI (in HAYAJ.\.;II and ICHIKAWA, 1965) the Lower Cretaceous formations' in the considered that Wakinoa was a common Asian Continent including the Koreo­ ,ancestor of, Trigonioides,' (s; s.) and Japanese region since the genus" Tri­ Nippononaia or that Trigonioides'(s.s.) was gonioides was first established by derived from 'Nippononaia through KOBAYASHI and SUZUKI (1936) from the Wakinoa with 'regard to' the hinge Nagdong Subgroup, Korea. They have structure ,and other' morphologic charac­ been known as indices in the non-marine ters. After thal, I revised the evolution­ Cretaceous formations of Asia. But, for ary lineage such as Koreanaia-Wakinoa further precise correlation, and the ap­ Nippononaia-Trigonioides (s. s.)-Kuma­ propriate allocation of their taxonomic motoa from the stratigraphic relations position, the construction of their and their;. morphologic characters' and phylogeny is indiE!pensable. The for­ presented the Koreanaia cheongi as an mations yielding these species, unfor­ ultimate ,ancestor of the trigonioidid tunately, are separat,ely distributed here species (1976, .1978b). The evolutionary and there, and thus the phylogenetic trend was' also supported from the com­ relations amqng them have not yet been parison of the T. (s. s.) kodairai and T. definitely constructed as mentioned pre­ (s. s.) pauc.isulcatus (YANG, 1978a). viously (YANG, 1978a). Recently, I discovered a new fossil OTA (1963) regarded Trigonipides(s.s.) locality) 'from the lowermost formation * Received July 26, 1979; readJan~'ary 22, of the Gyeongsang Group, Korea. Among 1979, at the Annual Meeting of'the 'Palae­ the collection, a new trigonioidid species ontological Society of Japan' at. FukilOka. described 'below presents a fairly inter- 223 224 Seong Young YANG

2km tI;;;g;J;;b;g;;a:;;;;;;;=~=;;;;j1 Text-figure 1. Geologic map around the fossil locality (generally after 5.0. Ci-iOl and Y.!. K WON, 1970). 1. Pre-Gyeongsang gneiss, 2. Pre-Gyeongsang granite, 3. Yeonh­ wadong Formation, 4. Hasandong Formation, 5. Dongmyeong Formation, 6. Acidic dyke, 7. Alluvium. x Fossil locality. In the index map at the lower right corner, D: Daegu, J: jinju, B: Busan, G.S.B.: Gyeongsang Main Basin. esting feature certainly considered to ment and also critical reading of this be intermediate between K. cheongi and paper, and to Miss Gumja LEE of the W. wakinoensis. This is supported also Kyungpook National University for her by the stratigraphic evidence. assistance on field and laboratory works. The other new species is referred to This study was financially supported Pseudohyria, which has not been reported by the Korea Science & Engineering from Koreo-Japanese region. From the Foundation (KOSEF). stratigraphic occurrence, the new species of Pseudohyria is possibly an ancestor of Stratigraphic Notes various species of Pseudohyria reported from the Asian Continent. There have been different proposals This is to report systematically the about the stratigraphic subdivision of two new species with some brief notes the Gyeongsang Group by several authors, on the stratigraphy of the Gyeongsang but I do not give any comments on them Group. in this paper. In this paper, the current Acknowledgements-I would like to ex­ scheme of subdivision is used as shown press my sincere gratitude to Emeritus in Table 1. Professor Tatsuro MATSUMOTO of the The Gyeongsang Group is noncon­ Kyushu University for his kind encourage- formably underlain by a complex gener- 710. New bivalves from Gyeongsang Group 225 ally composed of gneisses and granites, The relation of the two subgroups, but in one small area of the northern the Nagdong and the Sinla, is apparently margin of the Gyeongsang Basin, the observed as conformable at least near group is in contact with the possibly the type-section. The ruditic rock of upper Jurassic Myogog Formation with the Paldal Formation shows a gradual angular unconformity, from which change from the arenites of the Chilgog Koreanaia cheongi was described (YANG, Formation lying below generally in the 1976). Assuming that the Yeonhwadong northern area of the basin. However, Formation next above the regional un­ in the southern area, an abrupt lithologic conformity is almost of the same age change at the boundary is observed, throughout the basin, K. cheongi must which leads us to regard the relation as be chronologically earlier than the disconformable. The two subgroups are present species. fairly well distinguishable from each

Table 1. Current scheme of subdivision of Gyeongsang Group. -1------~- I Bulgugsa intrusives 1------,- intrusive I I Jusasan andesites I ----I I I Geoncheonri Fm. ------a.. Chaeyagsan basalts T. (s.s.) paucisulcatus or Jindong Fm. g Sinla c:: Subgroup Banyaweol Fm. l:) 1------l:) Haman Fm. Z <: (f) Hagbong basalts l:) Zo Paldal Fm.* (iI ______~_ >­ - conformity (or dis conformity) l:) I Chilgog Fm. ------1 Dongmyeong Fm. * Nagdong ------Subgroup Hasandong Fm.-T. (s.s.) kodairai ------Yeonhwadong Fm.*-Nippononaia ryosekiana, T. (K.) bongkyuni, I Ps. matsumotoi ------~------unconformity Pre·Gyeongsang complex (granites, gneisses) orM~ogog Fm.-T. (K.) cheongi

-'------.,----,------~---~ In spite of CHANG'S withdrawal (1975) of his own proposal (1966) of *Yeonhwadong and *Dongmyeong formations for Nagdong and Jinju formations, respectively, I prefer to use the Yeonhwadong and Dongmyeong formations, as the name Nagdong has - been familiar to geo· logists broadly meaning the lower part of the Gyeongsang Group such as Nagdong flora and Nagdong fauna since YABE (1905), and above all, the Nagdong is also used to the subgroup, and the name Jinju is derived from the remote distance from the -type·section.- The *Paldal formation has been occasionally used for the Sinla conglomerate since SUZUKI (1943), and seems more desirable than the latter on the same reason as above. The Paldal is derived from the Paldal·gyo (Paldal bridge) at the type-locality near Daegu. 226 Seong Young YAAG other by different lithology, that is, the Nagdong is composed of rudites, arenites and lutites, while the Sinla contains ~ predominantly lutites and subordinately LL ~Sh arenites besides the basal conglomerate <.!) ~~Ms-- of the Paldal Formation. Therefore, it Z seems to be more reasonable to divide o ...... ······SS the group into the two subgroups than o EIJ any other schemes of subdivision. And ~ ~Ad there is no problem in stratigraphic :c comparison between Geoncheonri For­ z Im'blcg mation (with T. (s. s.) paucisulcatus) and @ Hasandong Formation· (with T. (s. s.) > mGr kodairai). LLo l!;!\Gn The subgroups are divided into for­ mations generally on the grounds whether the reddish beds are intercalated or not. However, on account of dis­ continuity of the reddish beds, they can not be considered as appropriate key beds (YANG, 1972). Therefore, it is quite 100m difficult to draw chronology in detail from the lithologic units, formations, especially in correlation of the two areas of a great distance aparts. For instance, no one can say, in the present state of knowledge, whether the lower Lower Yeonhwadong Formation near Goryeong be in fact lower than the middle Lower Text-figure 2. Columnar section of Yeonhwadong Formation near Waegwan. lower part of the Yeonhwadong Formation, And so the locality of Nippononaia showing the stratigraphic horizon of the fossil locality. Sh: shale, Ms: mudstone ryosekiana near Waegwan is hardly or siltstone, Ss: sandstone, Ad: acidic comparable with that of the present fossil dyke, Cg: conglomerate, Gr: granite, Gn: locality. However, the Lower Yeonhwa­ gneiss. dong Formation and the Middle Hasandong Formation can be compared with each locality was mapped by CHOI and KWON other with some chronologie sense. The (1975), and Text-figure 1 is adapted from present locality falls under the Lower their geological map with some modi­ Yeonhwadong Formation. While the fication made by me. The area is located occurrences of T. (s. s.) kodairai are con­ on the western margin of the central fined to the Middle Hasandong Formation part of the Gyeongsang Basin and even though the fossils occur very spora­ consists of the pre-Gyeongsang complex, dically. Thus, the present. locality can the lower part of the Gyeongsang Group be said to be stratigraphically lower and the acidic dyke as illustrated in than thdse of T. (s. s.) kodairai. Text-figure 1. The geology around the present fossil 710. New bivalves from Gyeongsang Group 227 Systematic Description be crenulated in some species. Other Superfamily Unionacea characters same as the original diagnosis (Y ANG, 1976, p. 320). Family Trigonioididae Cox, 1952 Subfamily Trigonioidinae Cox, 1952 Trigonioides (Koreanaia) bongkyuni, sp. nov. Genus Trigonioides KOBAYASHI & PI. '2.7, Figs. 1-12; Text·fig. 3 SUZUKI, 1936 Etymology-The specific name is dedi. Subgenus Koreanaia YANG, 1976 cated to Professor Bong Kyun KIM of Type-species-Koreanaia cheongi YANG, the Seoul National University who has 1976. contributed much to the paleontology of Remarks-Koreanaia was originally Korea. proposed as an independent genus on Material-Holotype (KPE 2190, PI. 27, account of its large angle of the V­ Fig. 9) and forty six para types (KPE sculptures on the median part and 2180-89, 2191-2226), collected from a lamellar hinge teeth. Such a combi­ horizon in the lower part of the Yeonh­ nation of characters had been unknown wadong Formation, Nagdong Subgroup, in the trigonioidid genera, i. e., Trigoni­ Gyeongsang Group (ColI. S.Y. YANG). oides, H offetrigonia, Nippononaia and Description-Shell medium in size Wakinoa. However, a new species (about 10-60 mm in length) generally described below is certainly referred to suboval or subquadrate in outline sub­ Koreanaia on account of its similar sur­ equilateral and equivalve, moderate in face ornamentation and outline, but the inflation; anterior margin well rounded, hinge teeth are not lamellar but finely posterior one rather straight, ventral crenulated like Wakinoa. It can be margin broadly arcuate; ratio of L/H regarded as a member of Koreanaia with about 1.3; test of moderate thickness; dentition of Wakinoa or a member of umbo slightly prosogyrous,· placed at Wakinoa with sculpture of Koreanaia. about two-fifths of the shell length from Therefore, it is considered as an inter­ the anterior extremity, projected slightly mediate species between Koreanaia and above. the hinge line; escutcheon and Wakinoa, that is, a link-species in the lunule indistinct. lineage from Koreanaia to Wakinoa. If Surface ·ornamented with V-shaped Wakinoa is considered as one of the sub­ ribs in the median part and reversed genera of Trigonioides (OTA, 1975; V-ribs on both of the anterior and the HAY AMI, 1975), it is reasonable to treat posterior sides. The angles of the Koreanaia also as another subgenus of median V-ribs about 30-45 degrees and Trigonioides. those of the reversed V-ribs on both sides Subgeneric diagnosis (emend.)-Hinge about 50-60 degrees. The line linking plate moderate in breadth, provided with the apices of the median V-ribs prosocline, opisthocline pseudocardinal and postero­ forming about 80 degrees with the ventral lateral teeth; the pseudo cardinal ones margin. The ribs and grooves on the two or three in left valve, two in right posterior half stronger and wider than valve, and the postero-Iateral teeth two those on the anterior half; the former in left valve, one in right valve. The ones run downward and gently curved hinge teeth typically lamellar but may forward, while the latter ones run rather 228 Seong Young YANG

interval and prominence. Posterior ridge running from the umbo to the postero­ ven tral corner. Hinge plate IT_oderatein breadth, provided with pseudocardinal and postero-Iateral teeth; the pseudocardinal ones two on each valve, the postero-Iateral ones one on right valve, two on left valve, forming the following dental formula; 5 3 PIII 4 2 PII PIV where 5: narrow and elongated with fine transverse crenulations on the ventral (lower) side onl y, parallel to the antero-dorsal marg in, 3: stout and high, with fine trans­ verse crenulations on both sides, subpara llel to the anterodorsal margin, Pill : narrow and elongated, w ith very fine transverse crenulations on both sides, parallel to the postero-dorsal margin, 4: stout and high, with fine trans .. verse crenulations on both sides, parallel to the antero-dorsal margin, 2: narrow and low, with fine trans­ verse crenulations on dorsal (upper) side on ly, subparallel to the antero-dorsal margin, PlI : narrow and elongated, w ith very fine transverse crenulations on dorsal side onl y, parallel to the postero-dorsal margin, PlY: narrow and elongated, more or less lower and shorter than PlI, with very fine transverse crenulations on ventral side only, parallel to the postero-dorsal margin. T ext-figure 3_ T rigonioides (Koreanaia) Two adductor scars subequal in size; bo ngkyuni, sp_ nov. a: surface ornamet­ anterior one semicircular, strongly im­ ation and the outline of left valve, b: pressed, accompanied with a minute internal structure of right valve, c : inter­ distinct pedal scar; posterior one sub­ nal structure of left valve. The sculpture ~ircular and larger, but not so distinct_ impressed on the internal surface is pro­ babl y due to the erosion of the inner la yer. The internal mould provided with im­ pression of V -shaped ornaments on the straightly downward. The median ribs flank and with crenulations around the number more than 13 in the anterior ventral margin. Umbonal cavity moder­ balf and 9 in the posterior half of the ately deep_ large specimens. The whole surface Ob se1-vation- The holotype (KPE 2190) ornamented also with fine numerous is an ex ternal mould of right valve_ concentric growth-lines of irregular The para types are also external or inter- 710. New bivalves from Gyeongsang Group 229 nal moulds. The tests were mostly while those of K. cheongi number 17 in dissolved out. The internal structures the anterior half and 13 in the posterior. can be observed on some internal moulds. Above all, the hinge teeth of the present Among the type-specimens, seven are species are clearly crenulated, while conjoined, twenty four are right valves those of K. cheongi are not crenulated, and fifteen are left valves. The speci­ rather lamellar. The crenulations of the mens at hand are mostly deformed to hinge teeth are quite similar to those of some extent. Besides the type-specimens, Wakinoa wakinoensis, but the surface many fragmentary specimens were ornametation distinctly differs from that collected. of the latter. In short, the present Occurrence-The specimens described species may be comparable with Wakinoa here were collected from the black shale in the hinge while it resembles Koreanaia at Weolmagdong, Ssangrim-myeon, in the surface ornamentation, especially Goryeong-gun, Gyeongsangbug-do, Korea in the large angle of the V-sculptures. (see Text-figure 1). The black shale In other words, the present species belongs contains abundantly the following neither to typical Wakinoa nor to typical molluscan species besides the described Koreanaia. But it is rather reasonable one and fragmental remains of plants. to assign the presen t species to one of the two subgenera than to propose Nippononaia ryosekiana (see YANG, 1978a) Nagdongia cf. sod YANG another independent genus or subgenus. Pseudohyria sp. (described below) In this case it is practically more con­ Micromelania? katoensis SUZUKI venient to classify the fossil species on Viviparus sp. the basis of the surface ornamentation rather than the internal structures for Measurements (in mm)- the future identification. Specimens Length Height Hoffetrigonia diversicostatus (HOFFET, Right valve (KPE 2180) 15.3* 13.1+ 1937) and H. robusta (KoBAYASHI, 1968) Left valve (KPE 2182) 56.2+ 42.9+ are similar to the present species in the Left valve (KPE 2183) 17.0+ 9.6* large angle of V-sculpture on the median Right valve (KPE 2184) 28.7+ 22.2 surface, but differ in their opisthogyrous Right valve (KPE 2185) 25.9+ 19.0+ umbo, finer subradial ribs on the anterior Conjoined valves (KPE 2187) 57.6 half and stronger inflation. Right valve (KPE 2189) 33.9 24.2+ If the phylogenetic series of Koreanaia­ Right valve (KPE 2190) * 56.6 38.1+ Wakinoa-Trigonioides (s. s.)-Kumamotoa Left valve (KPE 2192) 38.8+ 31. 3 is assumed (OTA, 1963; HAYAMI and Right valve (KPE 2202) 43.4 32.3+ ICHIKAw A, 1965; and YANG, 1976), the Right valve (KPE 2220) 10.8 6.3+ present species can be inserted between * holotype K. cheongi and W. wakinoensis. Comparison-The present species is similar to Koreanaia cheongi YANG, Subfamily Pseudohyriinae 1976 in the surface ornamentation and outline, but its ribs and grooves are KOBAY ASHI, 1968 much stronger and wider than those of Genus Pseudohyria MACNEIL, 1936 the latter. The subradial ribs of the present species number about 13 in the Type-species - Pseudohyria gobiensis anterior half and 9 in the posterior, MACNEIL, 1936 230 Seong Young YANG Pseudohyria matsumotoi, sp. nov. where 5: narrow and elongated, parallel to the antero-dorsal margin, occasionally in­ PI. 28, Figs. 1-8, Text-fig. 4 distinct, Etymology-The specific name is dedi­ 3: stout and high, subparallel to the cated to Professor Tatsuro MATSUMOTO antero-dorsal margin, of the Kyushu University who has greatly 1a: low and short, immediately below the umbo, nearly vertical, contributed to the Cretaceous strati­ 1b: low and short, smallest in the graphy. right valve, immediately below the umbo, Material-Holotype (KPE 2163, PI. 28, nearly vertical, Fig. 1) and twenty eight paratypes (KPE PIlI: distinct and elongated, parallel 2151-62, 2164-79), collected from the to the postero-dorsal margin, lower horizon of the Yeonhwadong 4: stout and prominent, parallel to the Formation, Nagdong Subgroup, Gyeong­ antero-dorsal margin, sang Group, Korea (ColI. S.Y. YANG). 2: stout and high, subparallel to the Description-Shell fairly large in size antero-dorsal margin, (about 60-85 mm in length), trigonally l'a: low and short, nearly vertical, suboval or suborbicular in outline, fairly PH and PIV: narrow and elongated, parallel to the postero-dorsal margin. inflated; subequilateral and equivalve; anterior margin well rounded, postero­ These hinge teeth neither crenulated nor dorsal one rather straight, postero-ventral striated, but rather lamellar. corner rather angulate, ventral margin Two adductor scars subequal in size; broadly arcuate; ratio of L/H about 1.2; anterior one semicircular, strongly umbo fairly high and prominent, slightly impressed, accompanied with a minute prosogyrous, situated nearly centrally, but distinct pedal scar, posterior one escutcheon and lupule indistinct; test subcircular and larger, but not so moderately tbick. distinct. The internal mould provided Surface ornamented with radial costae with impression of the surface radial and concentric growth-lines; the costae costae on the flank, especially distinct indistinct near the umbo and on the on the posterial part. Ventral crenu­ anterior half, but becoming gradually lation on the inner side not so distinct. prominent toward postero-ventral side. Umbonal cavity moderately deep. The costae on the postero-dorsal periphery Measurements (in mm)- being widely separated tangentially from the posterior ridge. The radial costae Specimens Length Height number 13 or more. Posterior ridge Left valve (KPE 2151) 67.7+ 58.3+ fairly prominent. Right valve (KPE 2152) 30.1+ 26.4+ Hinge plate moderate in breadth, Right valve (KPE 2153) 75.5+1- 60.6+1- provided with opisthocline pseudocardinal Right valve (KPE 2154) 85.5+ Left valve (KPE 2160) 80.2+ 62.2+1- teeth and postero-Iateral teeth; the pseu­ Left valve (KPE 2163) * 69.3+ 52.7+ docardinal ones three or four on right Left valve (KPE 2166) 12.0+ 10.9+ valve, three on left valve, the postero­ Right valve (KPE 2174) 65.1+ 55.7+1- lateral teeth one on right valve, two on * holotype left valve, forming the following dental formula: Observation-The holotype (KPE 2163) j5t 3 1a 1b PIlI is an internal mould of left valve. 4 ---2--1'a --- ~PIC --P"iV Many of the other specimens are also 710. New bivalves from Gyeongsang Group 231 specimens but become distinct with growth. Occurrence-Same as described above (Koreanaia bongkyuni). Comparison-At a glance, the present species looks similar to some species of Plicatotrigonioides from U.S.S.R.(MARTIN­ SON, 1965, pi. 3, fig. 6) and from Thailand (KOBA Y ASHI, 1968, pi. 20, fig. 1) in the trigonally suboval outline and surface ornamentation. But those species are generally ornamented with rather strong costae nearly on the whole surface, and the costae on the postero-dorsal part start 9.irectly from the last posterior radial. costa which runs from the umbo to the postero-ventral corner. The ventral crenulation on the inner margin is rather regular and subquadrate in that genus (MARTINSON, 1965, pi. 6, fig. 2) unlike other trigonioidid species. The present species is very similar to Pseudohyria cardiiformis ferganensis MARTINSON in the surface ornamentation and internal structures. But in the latter the radial costae climb up to near the umbo, and are well developed even on the anterior half. So far as the illustration is relied upon (MARTINSON, 1965, pi. 2, fig. 2), P. c. ferganensis possesses two or three pseudocardinal teeth on the right valve, while the present species possesses three or four Text·figure 4. Pseudohyria matsumotoi, ones on the right valve. With respect sp. nov. a: surface ornamentation and out· to the surface ornamentation, the present line of left valve, b: internal structure of species is rather similar to P. d. cardii­ right valve, c: internal structure of left formis (MARTINSON, 1965, pI, 2, fig. 4) from valve. U.S.S.R., but the latter is more elongated internal or external moulds and frag­ laterally, and not so high. ments. Thererefore, the description is Remarks-Many species referred,to the supplemented by the para types. genus Pseudohyria have been reported The immature small specimens are from Southeastern U.S.S.R. and China. generally suborbicular in outline, but They are generally of upper Cretaceous gradually become trigonally suboval with as illustrated in Table 2, while the growth. The posterior costae or pli­ present species is probably of lower cations are not distinct in the small Cretaceous (see YANG, 1978b). 232 Seong Young YANG

Table 2. Stratigraphic occurrences of Pseudohyria spp. (original data after MARTINSON, 1965, 1969; Ku, 1976) Pseudohyria SPECIES NEOC. APT. .-_.ALB. CEN. TUR. SAN.-DAN. P. javanica .-_. c:::: P. babatagensis . __ . P. rnujanica . . . P. plicatensis __ If) P: kysyl kumaensis .--- P. k. aralica .--. If) P. ferganensis .--. P. mongolensis radiatus .--- ::> P. tachtamyshensis .--. P. gobiensis itemirica .--. P. triangularis P. tuberculata ._-_. « P. obliqua - Z P. cardiiformis - P. gobiensis K 1 ·--K 2 :c P. sinkiangensis P. aralica U P. songhuaensis - ~ P. matsumotoi, sp. nov.

Explanation of Plate 27

Figures 1-12. Trigonioides (Koreanaia) bongkyuni, sp. nov. 1. Left valve (KPE 2197), internal mould, la; side view, showing the impression of the surface ornaments, Ib; dorsal view, showing the crenulated hing teeth. 2. Left valve (KPE 2182), internal mould, side view, showing the crenulation on the antero·ventral margin, the impression of V-shaped ornaments on the posterior flank, the muscle scars and the crenulated hinge teeth partly, the postero-ventral part broken out. 3. Right valve (KPE 2220), internal mould, showing the impression of V -shaped orna­ ments and the hinge teeth, immature specimen. x 2. 4. Left valve (KPE 2186), internal mould, showing the crenulated pseudocardinal hinge teeth and the muscle scars. 5. Left valve (KPE 2191), external mould of the postero-dorsal part. 6. Left valve (KPE 2192), external mould, showing the crenulated pseudocardinal hinge teeth. 7. Right valve, clayey cast of the external mould (KPE 2184). 8. Right valve (KPE 21948), antero-dorsal part broken out, 8a; external mould, 8b; clayey cast. 9. Right valve, clayey cast of the external mould (KPE 2190), holotype. 10. Left valve (KPE 2196), external mould, strongly compressed laterally. 11. Right valve, clayey cast of external mould (KPE 2188). 12. Conjoined valve (KPE 2187), external mould, antero-dorsal part broken out, 12a; clayey cast of right valve, 12b; clayey cast of left valve. All figures are approximately of natural size, unless otherwise stated. Loc.: Weolmagdong, Ssangrim-myeon, Goryeong-gun, Gyeongsangbug-do, Korea (see Text-figure 1) • YANG: New bivalves from Gyeongsang Group Plate 27 710. New bivalves from Gyeongsang Group 233

The hinge teeth of the upper Cretace­ Dam site in the northern part of the ous species of Pseudohyria, that is, P. Khorat Plateau, Thailand with a note on aralica, P. tuberculata, P. cardiiformis the Trigonioididae. Ceol. Palaeont. S.E. and P. aff. gobiensis, are more or less Asia, vol. 4, p. 109-138, pis. 20-23. distinctly crenulated and are similar to -- and SUZUKI, K. (1936): Non·marine shells of the Naktong.Wakino series. those of Wakinoa and Plicatounio, but Japan. Jour. Ceol. Ceogr., vol. 13, nos. somewhat different from the regularly 3-4, p. 243-257, pis. 27-29. crenulated teeth of the species of Tri­ Ku, C. W. et al. (1976) : Fossil lamellibranchs gonionioides (T.) and Kumamotoa. Up to of China. Nanking Inst. Ceol. Palaeont., now, Pseudohyria is first found from Acad. Sinica, p. 1-522, pis. 1-150. the Lower Cretaceous formation in Far MACNEIL, F. S. (1936): Notes on Pseudohyria East Asia, and the hinge teeth of P. gobiensis gen. et sp. nov. from the Iren matsumotoi are not crenulated but lamellar Dabasu formation at Iren Dabasu, Inner as described above. As the phylogenetic Mongolia. In F.R. MORRIS: Central Asia relation can be read in the hinge teeth in Cretaceous time, Bull. Ceol. Soc. Amer., vol. 47, no. 9, p. 1477-1534, pis. in the series Koreanaia-W akinoa-Trigoni­ 1-2. oides (s. s.)-Kumamotoa, a similar trans­ MARTINSON, G. G. (1965): Biostratigraphy formation of hinge teeth may be expected and fauna of Cretaceous continental in the phylogeny of the Pseudohyriinae. deposits. (in Russian) . Sci. Acad. U.S.S.R., p. 101-152, pis. 1-11. -- (1969): Biostratigraphy and fauna of References the Cretaceous continental system in CHANG, K. H. (1966): Stratigraphy and sedi· Tadzik basin, Kizilkum and along the mentation of Nagdong Subgroup (Lower river Chura in the vicinity of Taskhent. Cretaceous), Kyungsang province, south· ibid., p. 18-50, pis. 1-6. ern Korea. Jour. Ceol. Soc. Korea, vol. OTA, Y. (1963): Notes on the relationship 2, no. 1, p. 17 -5l. of Trigonioides and Plicatounio, non­ (1975): Cretaceous stratigraphy of marine Mesozoic bivalvia from eastern southeast Korea. ibid., vol. 11, no. 1, p. Asia. Ceol. Rept. Hiroshima Univ., no. 1-23. 12, p. 503-512. CHOI, S. O. and KWON, Y. I. (1970): Expla­ -- (1975): Notes on the genus Trigonioides natory text of the geologic map of (Bivalvia). Bull. Fukuoka Univ. Educ., Gujeong sheet (1/50,000). Ceol. Surv. vol. 24, pt. 3, p. 79-98. KOlea. Seoul, p. 1-9, pis. 1,2. SUZUKI, K. (1943): Restudy on the non· Cox, L. R. (1952): Notes on the Trigoniidae marine molluscan fauna of the Rakuto with outline of a classification of the series in Keisyo-do, Tyosen. Jour. Sigen­ family. Proc. Malac. Soc. London, vol. kagaku Kenkyusyo, vol. 1, no. 2, p. 189- 92, nos. 2-3, p. 45-70, pis. 3-4. 219, pis. 14-19. HA Y AMI, I. (1975): A systematic survey of YABE, H. (1905): Mesozoic plants from the Mesozoic Bivalvia from Japan. Univ. Korea. Jour. Coli. Sci., Imp. Univ. Mus. Univ. Tokyo, Bull. 10, p. 1-228, pis. Tokyo. vol. 20, no. 8, 1-59, pis. 1-4. 1-10. YANG, S. Y. (1972): On the distribution of -- and icHIKAWA, T. (1965): Occurrence reddish beds of Hasandong formation in of Nippononaia ryosekiana from Sanchu northern part of Daegu-W aegwan area. area, Japan. Trans. Proc. Palaeont. Soc. Theses Coli. Crad. Sch. Educ., Kyungpook Japan, N.S., no. 60, p. 145-155, pI. 17. Univ., vol. 3, p. 77-9l. KOBAYASHI, T. (1968): The Cretaceous non· -- (1976): On the non-marine molluscan marine pelecypods from the Nam Phung fauna from the upper Mesozoic Myogog 234 Seong Young YANG

formation, Korea. Trans. Proc. Palaeont. 333-348, pis. 45-46. Soc. japan, N. S. no. 102, p. 317-333, pis. -- (1978b): On the discovery of Nippono­ 33-34. naia ryosekiana from Gyeongsang group, -- (1~78a): Ontogenetic variation of Tri­ Korea. jour. Geol. Soc. Korea, vol. 14, gonioides (s.s.) paucisulcatus (Cretaceous no. 2, p. 33-34, pI. 1. non-marine bivalvia). ibid., no. 111, p.

Ancheon *JII, Anlimdong ***foJ, Banyaweol ~:eiYJ, Bulgugsa {blE~, Chaeyagsan :f*~W, Chilgog ~:fr, Daegu *Ji'~, Dongmyeong JR:!Jij, Geoncheonri ¥l;JII11, Goryeong ii1li~, Gujeong Atr, Gyeongsang ~~, Habcheon Il*JII, Hagbong .~, Haman ~*, Hasandong ~WfoJ, Jinju wm, Jusasan *Ti'JiW, Myogog 91l:fr, Nagdong mJR:, Paldal Ait, Sinla ~lI, Ssangrim-n.yeon ~**ITii. Waegwan ~U!i; Weolmagdong YJ :iJfoJ, Yeonhwadong ~fEfoJ.

~lErml.j';1fiJi!fUHE::::ttJ'l.~:fiI!ft:Ot;::'?"'-C: ~j';1fiJi!fUJilrmlJi!fL'ib7.> ~fE11l!1Ji!ftpt> HE ill L.. t.::. ilikf*lIJiJilmft:o q:,::::ttJ'l. 2 ~f1~~~"t 7.>. -t ~ q:" Trigonioides (Koreanaia) bong­ kyuni, n. sp. It-t~~iHi~Mlilt Koreanaia ~~~~.J~lt Wakinoa ~~5FL..-C"'7.>. ;:.;h t> ~M~ C Ji!f1f:~fj{J~f*tJ, t>~ljwr L.. -C, ;:. ~~:fiI!lt!l4~fj{JtJ: Koreanaia tJ't> Wakinoa i t.::.lt Trigonioides (s.s.) t;::~ft"t 7.>*7U~q:,r,,'~c fW~ ~;h7.>. Pseudohyria matsu­ motoi, n. sp. It-t~Ji!f1f:~fj{JOOf*~~.::t -c, Lf"iL'7~7*~tJ't>¥jH!r~;ht.::. Pseudohyria spp. ~m9i;tuJ:7.>PTIi~1i.tJtib7.>. ~ ffi. *

Explanation of Plate 28

Figures 1-8. Pseudohyria matsumotci sp. nov. 1. Left valve (KPE 2163), internal mould, holotype. la; side view, showing the pseu­ docardinal teeth, the muscle scars, and the impression of radial plicae on the posterior part. Ib; dorsal view, showing the hinge teeth, lc; rubber cast, showing the internal structures. 2. Right valve (KPE 2169), internal mould, posterior part broken out, 2a; dorsal view, showing the pseudocardinal hinge teeth, 2b; rubber cast, showing the pseudocardinal teeth' and the muscle scars. 3. Left valve (KPE 2166), internal mould, showing the hinge teeth and the muscle scar, immature specimen. x 1.6. 4. Left valve (KPE 2152), internal mould, showing the pseudocardinal tooth. 5. Left valve (KPE 2173), internal mould, dorsal view, showing the hinge teeth. 6. Left valve (KPE 2157), posterior part only, 6a; external mould, showing the radial plicae on the posterior part, 6b; clayey cast. 7. Left valve (KPE 2151), internal mould, showing the hinge teeth, the muscle scar and the impression of posterior plicae. 8. Right valve, clayey cast of KPE 2153, showing the radial plicae antero-dorsal and postero-ventral parts broken out. All figures are approximetely of natural size, unless otherwise stated. Loc.: Weolmagdong, Ssangrim-myeon, Goryeong-gun, Gyeongsangbug-do, Korea (see Text­ figure 1). YANG : New bivalves from Gyeongsang Group Plate 28 235

PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY OF JAPAN

~ ~ ~c • Possible feeding habit of Nautilus pompilius B *ti~¥J.J~~~ 124@]{7IJ~ft.1979~10Jl20 B t:. from the viewpoint of anatomy and its ~ti~*~w.~$ t:.:to~ ,"( Mil ~tLt.: (~~~74 impication for cephalopod paleobiology .. ~)o " Y. FUKUDA, K. TANABE and Y. KANIE Implosion of living Nautilus test under 1m A ~ iJil increasing pressure: its bearing on ce- i'¥tdIIIWf$ft~- £~ itiIEm:w- #ilI fl) 15 W('lljJa~1r. phalopod paleobiology ...... Y. KANIE, 15Jfi!1/'f ...... i1!lB35!:AA Y. FUKUDA, H. NAKAYAMA, .K. SEKI and Geological age of the N obori Formation, M. HATTORI Shikoku, as viewed from calcareous nan- i'fift$M~~.~Y~-fl).ff~m~i~V-~ nofossil evidences ...... T. TAKAYAMA -fl)~~~{-fl)M~M~ff~W.~~fl)~ffl .. B *i'fifrd7¥J:$~~:W-fl)rlNJm!;f;~1r.15 {-fl) 3- . ... ~1i$~!Jj· ~ ~f:iJj. 9=tili~1!J.I • ~nI*:J'[; :lfH;Jfi!I • i1!liliJfi!l ...... ;f".kilUl~7C Shell growth of living Nautilus in captivity tiRf!!WlJfi!lfffl)Jt~1r.15t:."?~'"( ...... ~ ;g ...... H. HIRANO and jECOLN members ~~~Afl)~~~*Jt~Jfi!I/'f~Jt~4~fl)~M SEM observations on siphuncles in ammo­ ~i¥J~t-t ...... ,1H~ m noids and living chambered cephalopods: 1r.15Jt~fl) f*~)ffy~ ~ {- fl) ~UIB)ffy ~ fl) ~f*t:.~ microstructures and their functional signi- i" 7.>~~ : 2 ~~fl)~t(; ...... /N;f~- ficance ...... Eocene planktonic Foraminifera from Chichi- .. I. OBATA, K. TANABE and Y. FUKUDA jima, Ogasawara (Bonin) Islands ...... Early jurassic plants in japan. Part 1: ...... Y. TAKAYANAGI and T. KATAYAMA Equisetales .... T. KIMURA and M. TSUJII *3ft$fJ!ljfl) 9=t;M9=t~ti!:t:.:toft 7.> JrEfl1r11.!Rff~ Cuticular study on the Ginkgo leaves from ~ti}jj!mfl)ft£ilt:."?~'"( ...... WB3 :w the Upper Cretaceous Omichidani For­ m*!Jjld)'l?ft.l:.lb"(~Ji ~tLt.: Miogypsina t:. mation, Ishikawa Prefecture, japan .... ,,?~,"( ...... •...... ••.....• ;f".k1LIE~ • ...... T. KIMURA and T. OHANA =¥Jli(itilEiIt¥J.Jfft:.&: L- t.: Pterophyllum ~t:. ,,?~, * t$-'~ili~-'*~~~'ilI~ ~ A new Chlamys from the Shitakara For- "( ...... ;f".k )~Jf;;~ mation of the Urahoro Group, Kushiro ~ll B ,!i!;:l1!!JlilGt:.&:i" 7.> PR1r.;fit1r.15t:. "?~ ,"( .... coal field, eastern Hokkaido .... Y. HONDA ...... ili~Mi;Jc· ilUlB31ft5!: • illB3$R] ~.Jfi!lfl)Jfi!I&·ti~¥J.J~I-JrE~~15~~fl)* A study of the pennatae trigoniids from 3fi¥Jft£1r.t:."?~'"( ...... {ii:~~!Jj Japan ...... M. TASHIRO tl*JIIJfi!1ff&:fl)/¥-iiM:J'l.M1r.15 ...... ~B3 ~ ~7J+*~p~AJfi!lfffl).::::..tlcJ'l.1r.15 ...... i1!lWf B * 9=t~ti!:fj(f*lIffJ¥J.J1r.15 fl) 2 • 3 fl) r~'JI:!i- ...... l¥~

...... T, MATSUl'viOTO and Y. MOROZUMI Neopetalodus, a new genus of Ellasmobran­ ~~!llrfQ)ggn-t*Q):liXM~t.::."?\""{ ...... chii from the Permian Akasaka Lime­ ...... '*'t!!:J!i~!X t!~ • '*')11 ~==. stone, Japan .. M. MURATA and T. UYENO ~71* Q) ==.~* :to .t If ='- 7 * Q) :liX1tY:~ t.::. "? \, ,"( ,;; Iv Iv *[1. r ~ ? -t ? i? Carboniferous trilobites of ...... *~mz Japan ... •T. KOBAYASHI and T. HAMADA J!i1ffft!llb4W~ c J!i~4WliIf~iYT ...... ~JiIi\j~~ M fl :til! M fl a BtIt~$~~m

1980~~il; • ~il; $t illl * ~ 1980~ 1 R25' 26a 19791j:.uR 25 a ~ 125 @I {1U ~ ~ ~ * ~ 1980~6 R29a 1980~4 R29a

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04Hi~f,!;j!9'l:DiJJ~(7)~~milt~ '? \" "C *~~J;l7'j-(7)~fi~f,!;j!9'l:DiJJ~ .1!bnJ(;~tJ: ct~.tt.~~hi!>1J-e~~mil~~'J!ci'"i!>~~, "it.:~fi1it(7) ~fm~C I..- "C~~tJ:1J~~~ J: I) mil I..- "CW\I..-\"c1ri~~hi!>:Ijj~ll, tJ:i!>~ t.:J:, ml!HR:/sb"ii'". tJ::t,;*~il;t~~1*(7)i*\"!9'l:DiJJ~ ·1!bnJ(;~c I..-"Cll, iWJa~VJij~DiJJ~, =:~Mffii3?t,\:f4~9If5e1!bnJ(;~, ~ ~~I),1itcl..-"C~iWJa~~.1it~c~~l)ti'". O{~:ti29~ (1lB;frl54~10R25a §err, 2000FJ) '/J~fUrr~ht I..-t.:. 1lB;frl54~ 1 m~m/lUJ-errtJ:bht.:::z P "f­ ry A r@l~:l<\tJ:f:;(7) J!:tIl!iJ, ~.;z,..t.: a *:1"0 J: L)(jl[~:tIl!C7) s1lli:~{tEJ t~'/J'A.,i'" i!> * !i ;/:;t- Iv~Jt, {tE(7)-ut9lt, -1 :/ ~:;t-::-- a :;t- IH ,f- - r tJ: c'/J~1!!I:'!lit~mJ!lt~h "C\" ti'". r {tEJ 111 ffit~ c (7)JlIji7H \"t.: I..- "ii'"'/J~, ~~7t':J~~t\lt~~~ I..- "C\"t.:t-: ~, §err(7)'I$~:t,;* I) I..- "C, tt~~~t&\,' L "C\"t.:t-: <1J~;6~fifU-ei'". ~1ri~(7)1Jll, 11iJ~ ~~**:ge c *%t-:~iJ'~m7t0'/J,~§J3~(7)J:, "f~~:t,;$~.;z,.. "f~ \" •. 'T980 fJililflrm~*i1f~ *~t*~llI!~ffll:tll!Jt~i1&:.4ifo~~~Jf

gerr~ a*ii~~~~ 1 9 7 9 ~ 12 R 25 a (:JJ JilU Jt Jj{ IK ~ &:. 2-4-16 1 9 7 9 ~ 12 R 30 a ~ rr a*~~$$~:/~-Pl (~ if 0 ~ JI( Jj{ 84780 11) ISS~ 0031-0204 (~ illS 0 3 - 8 1 5 - 1 9 0 3) • ~ ~ ~* ~'1ifJfinIE ~ • 116 % lOP .IilU ~ Jfi! Jj{ m** .!Ii IK fl 3i ~t 2 / 13 2.000 Fl ~VJij~.(:JJJilUI*~~:f!: &" EB ~ (ll illS 0 3 - 9 9 1 - 3 7 5 4) Transactions and Proceedings of the Palaeontological Society of Japan

New Series No. 116 December 30, 1979

CONTENTS

TRANSACTIONS 708. KOMURA, Seiichi: Eine neue Diatomeen-Gattung aus den oberneogenen Koitoi Schichten, Tenpoku, Hokkaido ...... 175 709. TASHIRO, Masayuki: A Study on the "Pennatae Trigoniids" from Japan .. 179 710. YANG, Seong Young: Some new Bivalve Species from the Lower Gyeongsang Group, Korea ...... 223 PROCEEDINGS ...... 235