ISSN 0031-0204

Transactions and Proceedings

of the Palaeontological Society of Japan

New Series No. 109

Palaeontological Society of Japan April 30, 1978 Editor Itaru HAYAMI Associate editors Tsunemasa SAITO and Tomowo OZAWA

Officers for 1977 - 1978

Honorary President: Teiichi KOBAYASHI President: Ryuzo TORIY AMA Councillors: Kazuo ASAMA, Kiyotaka CHINZEI, Takashi HAMADA, Tetsuro HANAI, Itaru HAY AMI, Syozo HAY ASAKA, Hisayoshi IGO, Tadao KAMEl, Kametoshi KANMERA, Tamio KOTAKA, Tatsuro MATSUMOTO, Tsugio SHUTO, Yokichi TAKA YANAGI, Toshimasa TAN AI, Hiroshi UJIIE Members of Standing Committee: Kazuo ASAMA (Finance), Kiyotaka CHINZEI (General Affairs), Takashi HAMADA (Foreign Affairs), Tetsuro HANAI, Ita­ ru HAYAMI (Transactions), Hisayoshi IGO (Planning), Kametoshi KANMERA (Special Papers), Ikuwo OBATA (Membership), Yokichi TAKAYANAGI ("Fossils"), Hiroshi UJIIE, Juichi YANAGIDA Secretaries: Ienori FUJIYAMA (Special Papers), Kunihiro ISHIZAKI ("Fossils"), Tsunemasa SAITO and Tomowo OZAWA (Transactions), Hiromichi HIRANO and Yasumitsu KANIE (Membership), Toshiyuki YAMAGUCHI (General Affairs) Auditor: Tatsuaki KIMURA

The fossil on the cover: Original figure of Podozamites Reinii GEYLER, 1877, from the Tetori group. GEYLER'S description marked the onset of modern palaeontology in 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. 109, pp. 223-2:'4, pis. 31, 32, April 30, 1978

684. DISCOACTINOCERAS AND THE DISCOACTINOCERATIDAE, FAM. NOV.*

TEIICHI KOBAYASHI

Japan Academy, Tokyo

Abstract. Discoactinoceras used to be placed in either the Huroniidae or the Polydesmiidae is quite distinct from them in the growth of intrasiphuncular stereo­ plasmic deposits from the actinoceroid to endoceroid type. Because its septal neck is of Armenoceras type, it must be a derivative from the common stock with the Armenoceratidae. In longitudinal section the septum looks sigmoidal by an adoral and adapical bent respectively near the conch and septal neck. From these distinc­ tions a new family, Discoactinoceratidae, is proposed for the genus. Here, not only Discoactinoceras multiplexum, the type-species of this genus, but also D. cf. multi­ plexum and D. okdongense, nov. from South Korea are described in detail.

Discoactinoceras known from South ceras. Therefore a new family, Discoac­ Manchuria and North Korea is an inter­ tinoceratidae, is here established. esting genus having shoulderedn nummuli Judging from the siphuncular structure like the Huroniidae, but its siphuncular this family indicates an aberrant branch structure is very complicated. Because issued from the common stock with the the description of its type-species and Armenoceratidae in the middle Toufan­ generic diagnosis written almost fifty gian or middle Mohawkian age by para­ years ago is inadequate, they are here llel specialization to the Endoceratida by redescribed. Discoactinoceras multiplexum the benthonic adaptation in the grown was monotypic. Five specimens contained stage. in SHIRAKI collection from South Korea represent two forms of this genus for one of which a new name is proposed. Family Discoactinoceratidae, fam. nov. Discoactinoceras has been placed in the Diagnosis:-Actinoceroid with a large Huroniidae or the Polydesmiidae, but marginal siphuncle whose deposits consist either one of them is unable to have it of outer annuli and inner tubular or con­ in its domain principally because of the ical sheathes; septa geniculated in pro­ possession of double structural elements ximal and distal parts; septal neck ar­ of the siphuncle. The family Georginidae menoceroid. recently proposed by WADE; from Aust­ Remarks: - Since FOERSTE and TEI­ ralia also have double elements in its CHERT'S reference (1930) Discoactinoceras siphuncle, but these elements are essenti­ has long been allocated in the Huroniidae, ally different from those of Discoactino- but as detailed below, it is sufficiently * Received June 16, 1977; read Oct. 16, 1977 distinguishable from that family. This at Kumamoto. genus must have been evolved from an 223 224 Teiichi KOBAYASHI unknown common stock with the Armeno­ annuli, but becoming later tubular or ceratidae, but the high specialization re­ conical sheathes; central cavity broad quires its isolation from that family, primarily, but later narrowing and be­ Judging from its complexity of the septa coming tubular; radial canals branching and siphuncle it is quite improbable that off from central cavity or tube and ex­ it is ancestral to the late Ordovician­ tending laterally through sheathes; stereo­ Silurian Huroniidae. Its siphunucular plasmic deposits undeveloped in camerae. structure is incomparable with the radi­ Surface of conch. apical end and body ally disposed longitudinal lamellae or chamber unknown. endosiphuncular blades by TEICHERT and Type-species: - Discoactinoceras 71lulti­ CRICK (1974) in Huroniella servenense plexu11l KOBAYASHI, 1929. (FOERSTE and SA V AGE, 1927). Remarks:-In the large siphuncle with This genus was once located in the shouldered nummuli and septal genicula­ Polydesmiidae by CHAO et al. (1965), but tion this genus resembles Huroniella. It, as I have alreadY detailed that family in however, differs essentially from Hllronia 1940 and 1977, Discoactinoceras has inner and Huroniella in the marginal position tubular sheathes on one side and its an­ of the siphuncle in this genus. The nuli do not grow in horn-shape as in that siphuncular deposits are unusually com­ family on th e other. plicated in this family. The genus was In the Georginidae tubular deposits allocated in the Polydesmiidae (CHAO et called endocones by VI' ADE (1977) some­ aI., 1965), but the siphunclar structure of times appear in the central cavity of that family is quite different from that Georgina and well developed in the cavity of this family. of iv!esaktoceras like in Discoactinoceras. The septa of this genus is more or In the radially lamellate structure of the less' sigmoidal, although its middle main nummulus and particularly in the so-called part is nearly straight. The sigmoidal engraft by VI' ADE, however, that family septa may be comparable to those of is quite distinctive. Gonioceras, but it is no more than a paral­ Thus. Discoactinoceras is isolated from lelism in the trend of specialization. the Huroniidae, Polydesmiidae, Georgin­ because Gonioceras is quite different in idae, or else in the Actino ceratida in most other characteristics. its double structure in the inner and Recently CHEN and LIU (1976) described outer parts of the siphuncle so far two new species of Discoactinoceras, that a new family should be instituted platyventrum and wuyangshanense, from for it. the middle part of their Machiakou suite Distribution :-Middle Ordovician; East­ in Shantung. The latter species appears ern Asia. to resemble D. okdongense, while the former is quite distinct from Discoac­ Genus Discoactinoceras KOBA YASH!, 1929 tinoceras in the Actinoceras-type septal neck and especially in the structure in Diagnosis: - Orthoconic actinoceroid the inner part of the siphuncle. with large marginal siphuncIe; septa Distribution:-Toufangian and its cor­ geniculated near siphuncle and shell wall; relatives in Korea, North China and septal neck armenoceroid ; siphuncular seg­ Southern Northeast China. ment very wide, shouldered near septal Recently CHEN and LIU (1976) distin­ neck; siphuncular deposits beginning with guished the Discoactinoceras- Loplwspira 684. Discoactinoceras and the Discoactinoceratidae 225

yentaiensis zone in the middle part of the Dawan formation and the Neichiashan their Machiakou suite in North China series of Central and South China where and Northeast China and considered the .series was subdivided into the Kuni­ Llanvirnian. Because their Machiakou utan limestone, Miaopa shale and Pagoda suite easily confuses the traditional Ma­ limestone in ascending order (CHANG, chiakou limestone, a few words are added 1964). According to Lu (1975) the Dawan here. formation is Llanvirnian plus the Azygo­ Ordovician rocks in North China were graptus suecicus zone and the .Neichiashan first classified in about 1921 into the series Llandeilian-middle Caradocian Yehli formation, Liangchiashan limestone (Sinoceras sinense zone) in age. and Machiakou limestone in ascending According to CHEN (1976) the post­ order, and the Machaikou fauna was Liangchiashan rocks of North China, correlated with the Black River or Mohaw­ namely the traditional Machiakou lime­ kian of North American by GRABAU stone, is classifiable into four suites, re­ (1922). This tripartition has long been stricting the Machiakou suite to a part in current use in China. but the Machia­ of the limestone and they are correlated kou limestone was subdivided into two to the North American sequence as be­ parts. The lower and upper Machiakou low. limestone were correlated respectively to

Suite Cephalopod zone North American correlative

Patou Gonioceras badonellse Mohawkian Kechuang None

Tofangoceras pauciannulatum Machiakou Stereoplasmoceras pseudoseptum Chazyan Ordosoceras quasililleatum Peianchuang Polydesmia zuezshanensis Whiterock

Subsequently, however, the Discoac­ tive. Incidentally, lower Chazy an or tinoceras-Lophospira yentaiensis zone was Whiterock of today is approximate to added at the middle part of the Machia­ Llanvirnian. while Black River is early kou suite (Lu et aI., 1976). Then, what Caradocian or thereabout in the British bears Lophospira yentaiensis on the zona­ sequence. tion is a question. Lophospira yentaiensis ENDO (1953) rectified the position of the ENDO is a member of the Kangyao fauna Kangyao formation as the subjacent unit which ENDO (1932) correlated to the early to the Ssuyen formation, eliminating the Chazyan or Mosheim fauna of eastern Wuting formation from the intercalation North America. The Mosheim limestone. between the two other formations and Alabama is lower Chazyan, but the Stones allocating it beneath the Kangyao. This River group in Tennessee and Kentucky means that the yentaiensis horizon is is Black River in age (TWENHOFEL et al.. higher than thought before. Likewise. it 1954). Therefore, neither Lophospira yen­ is probable for the Machiakou suite to taiensis nor abundant Lophospira suggests extend up into the early Mohawkian or merely Chazyan for the Kangyao correla- Blackriverian in view of the fact on the 226 Teiichi KOBAYASHI hiatus of any fossil in Kechuang suite. section. Siphuncle almost circular in According to CHEN (1976) Discoactino­ cross section, nearly as large as a half ceras occurs in the lower and middle of conch's diameter, located marginally parts of the Machiakou suite but not in or ventrally, distinctly nummuloidal with the upper part \vhich contains, however, broad central cavity but becoming nar­ Armenoceras manchurense, an associate row, longiconic or tubular where it is with Discoactinoceras mliltiplexum III surrounded by sheathes. Siphuncular North Korea. segment distinctly shouldered, but not As the result of the above discussion annulated at the top as often seen in it is concluded that Discoactinoceras as a huronioids. genus ranges through the lVlachiakou In longitudinal section septa more or suite whose range is post-Whiterock but less sigmoidal, suddenly bent forward probably pre-Trentonian. near shell wall and then ad nate with shell on distal side, but on the other side they are abruptly bent in- and backward, Discoactinoceras 11l11ltiplexum then sharply recumbent and inserted be­ KOBA Y ASH!, 1929 tween nummuli; main part of septum Plate 31, Figures 1-5, Text-figvx.os 1-2 between these two bents long, nearly straight or very slightly convex back­ 1929. Discoactinoceras mulliplexum KOBAY A­ ward. Connecting ring strongly convex SHI, Japan. Jour. Geol. Geogr., Vol, 5, on adoral side and broadly rounded on no. 4, p. 202, pI. 22, figs. a-d. the other side. Annuli in early stage 1931. Discoactinoceras mullipl eXU11l KOI3A YA· composed of some concentric layers, but SHI, Bull. Geol. Surv. Chosen ([(orea) , Vol. 11. no. 1, p. 56, pI. 4, figs. la-b. becoming roundly quadrate and separated from neighbouring neck rings by radial Description: - Conch large. straight, canals; subsequent layers less convex very slowly tapering, subcircl!lar in cross and connected with neighbouring ones; at length they become conical or tubular sheathes where, however, they are pene­ trated by radial canals at places. Endosiphuncle long, conical in adoral part, but narrow and tubular on the other side. Radial canals extending from it laterally with weak convexity on adapical side and terminating near median part of connecting ring. Septal suture appar­ ently ascending ventrally. Camerae free from stereoplasmic deposit. Surface of conch, apical end and body chamber un­ known. Observation :-In cross section of the holotype specimen it is seen that the siphuncle is in direct contact with the outer shell. judging from the sinuate Text.figure 1. Pharagmocone of septal sutures on the siphuncle exposed Discoactinoceras multiplexum. on the limestone slab, the sutures are 684. Discoactinoceras and the Discoactinoceratidae 227

ascending toward the venter. Armenoceras manchurense (KOBAYASHI), In the longitudinal section of the speci­ Onnoceras (Paraarmenoceras ?) tani (GRA­ men the boundary sheath between the BAU), Ormoceras nanum (GRABAU) and outer semicircular and inner tubular layers Stereoplasmoceras? submarginale (KOBA­ is particularly well defined. The more YASHI). Judging from the cephalopod inner sheathes are recrystallized, but association the multiplexum horizons at radial canals penetrate the recrystallized the two localities are considered coeval part at some places. In cross section of with each other. They are certainly the siphuncle the boundary sheath is cir­ within the Toufangkou limestone. cular but the circle takes zigzag course In the vicinities of P'yongyang, North and radial canals penetrate projections. Korea the Toufangian series consists of In the Cho'san specimen the boundary four units of strata in descending order sheath is clearly defined in the whole as follows: length of the siphuncle, but the more in­ ner sheathes are ill-preserved. 4. Nanso or Namjang formation, barren of fossils. Because the septa are thin and the camerae free from stereoplasmic deposits, 3. Unkaku or Unhak formation contain­ ing a copious fauna including Labechia, the camerate part was largely destroyed Lophospira, Ormoceras and Armeno­ and the siphuncle exposed. As the result ceras, etc. the outer surface of the nummulus was 2. Bantatsusan or Mandalsan formation eroded in these specimens in different containing Stereoplasmoceras and 01'­ degrees. moceras rarely. Comparison :-Without seeing the type 1. Maruyama or Hwansan formation specimen of this species SHIMIZU and yielding Polydesmia and cameroceroid. OBA TA (1935) expressed their opinion that this species is identical with Ar­ On the basis of the present knowledge menoceras submarginale (GRABAU) in pI. the Toufangian series in North Korea, VIII, figs. 5a-b, pI. XI, fig. 3, GRABAU, South Manchuria and North China is ten­ 1922, but the two species are quite dif­ tatively correlated as shown in Table 1. ferent in all essential characteristics of As discussed already (KOBAYASHI, 1977), marginal siphuncular position, septal geni­ the Maruyama, Leichuang and Peian­ culation, shouldered nummuli and the chuang faunas all characterized by Poly­ most complicate siphuncular structure of desmia are approximately coeval with this species. the Whiterock of North America. The Occurrence: - The holotype specimen Wuting fauna exclusive of Canadian fos­ was collected by K. MITSUISHI from dark sils would be about the same age, al­ gray banded limestone near Chiushukou though neither Polydesmia nor Ordosoceras in the Niuhsintai basin, Liaoning, North­ is contained in it. east China in association with Ormoceras The Machiakou limestone was primarily (Paraarmenoceras ?) tani (GRABAU) and named for the post-Liangchiashan lime­ Ormoceras (?) submarginale (KOBAYASHI). stone, although the superposition of the The second specimen was procured by Machiakou on the Lianchiashan limestone Chong-weon KIM from gray spotted was actually indeterminable, because the limestone at the northern cliff of Clailgp­ former in the Kaiping basin and the lat­ yong-dong, Nam-myeon, Ch'osan, P'yeon­ ter in the Liukiang coal-field were separ­ gan-bukto, North Korea together with ate exposures in eastern Hopei (formerly 228 Teiichi KOBAYASHI

Table 1.

I South Manchuria North China North Korea i KOBAYASHI, I 1966b I KOBAYASHI, I ENDO, OBATA, 1965 CHEN, 1976 I 1966a 1953 I Nanso i Tapu Hsiaofankechuang Patou I Ssuyen Tangshan upper Unkaku I I Toufangkou , Kangyao Lincheng middle Machiakou Bantatsusan I I Wushan lower ! Maruyama I Unnamed I Wuting Leichuang Peianchuang I

Chihli). The Machiakou fauna described the lower part of the Machiakou suite. by GRABAU, however, can safely be cor­ Ormoceras nudum and Armenoceras mal1- related to the Toufangkou and Unkaku churense, on the contrary, are considered faunas. Fossils are, however, uncommon a Tangshan member by OBATA and a in the Bantatsusan formation and appar­ late Machiakou member by CHEN respec­ ently absent in the Nanso formation. tively. Although it requires a further Similarly, the Tapu formation is almost investigation to solve the question, it is barren of fossils, although Stereoplasmo­ also probable that the horizon in ques­ ceras was later reported from the Hsiao­ tion lies in the lower Unkaku or the fankechuang stage and Gonioceras de­ Lincheng stage, if considered the rarity scribed from the Patou suite recently. of fossils in the Bantatsusan formation ENDO proposed the Ssuyen formation and its equivalents in Koreo-Manchuria. for the Armenoceras rich upper part and the Kangyao for the Lophospira rich lower part. Armenoceras, Lophospira and Discoactinoceras cf. multiplex1I11l other Middle Ordovician fossils are found KOBA YASHI, 1929 coexistent in the Toufangkou and Machia­ Plate 32, Figures 1, 2 kou limestones. OBA TA distinguished three stages in this fossiliferous limestone Tanggok specimen 9 cm long was cut and Chen also made its tripartition. into three pieces to see its cross section. Armenoceras, Stereoplasmoceras and To­ In the middle 62.5 mm 5 nummuli are jangoceras are common and persistent countable in longitudinal section in the genera all through these stages or parts. length of 23 to 24 mm. The siphuncle is Armenoceras coulingi and A. 1'esseri, for there 19 to 21 mm broad at nummulus example, belong to the lower division by and 16 to 18 mm broad at septal necks. CHEN but to the Lincheng stage by OBA­ The septal geniculation and recumbence T A. Thus the reference of these species at the neck are seen clearly near the disagrees between them. constriction. The nummulus is distinctly Ornzoceras tani is referred to the lower protruded antero-Iaterally. In the adoral Machiakou fauna as well as the Wushan part annuli are only partly lined back by fauna in association with Discoactinoceras tubular sheathes, while tubular and long multiplexum in the former. Therefore the conical sheathes are developed on the multiplexum horizon may be located in other part. In the middle part it is seen 684. Discoactinoceras and the Discoactinoceratidae 229 that radial canals are closed by a few stone or limestone lenses intercalated in sheathes. The apical angle of the endo­ the Chikunsan shale. siphocone or conical central cavity is about 10 degrees. The central cavity is Discoactinoceras okdongense half as wide as the siphuncle where it is KOBAYASHI, sp. nov. wide open on the adoral side. In cross section the annulus is penetrated by Plate 32, Figures 3-5 radial canals at a place on the adoral This species differs from the preced­ side. In the section of the adapical part ings chiefly in the subovate cross section sheathes are irregular in outline, but the of the siphuncle and relatively narrow central part appears more or less cre­ central cavity. It is represented by three scentic rather than circular or elliptical. specimens as follows: On the eroded surface of this specimen The largest specimen from Okdong some septa are seen to be extended from which is the holotype was a siphuncle 17 the siphuncle laterally and adorally. cm long, but it was cut into three pieces Hwangjiri specimen is an adoral part to see cross sections. Its diameter en­ of a phragmocone, 3.5 cm in length and larges from 10 mm at narrow end to 20 2 cm in diameter of siphuncle; nummuli mm at the other. Ten nummuli are dis­ 0.5 cm on an average. In longitudinal tributed in 40 mm in the adapical part, section septa are seen near the siphuncle but in 46.5 mm in the adoral part. In on its two sides. They are distinctly cross section the siphuncle is sub ovate geniculated just before insertion between and its broad flattened venter is in con­ constrIctIOns. Short septal brim adnates tact with the shell of the conch. In longi­ with septa. Not only the outer side but tudinal section the septum is inserted also the inner side of the annuli are some­ between two shouldered nummuli and what dissolved before fossilization, in­ abruptly recumbent at the end. The tubu­ sofar as can be judged from their irre­ lar deposit is seen to line annuli. The gular outline. Nevertheless it is certain central cavity is no more than one-third that the central cavity of the siphuncle the siphuncular diameter. is broader than a half of the siphuncular The recumbent septal neck is clearly diameter. No trace of tubular sheathes seen in the second specimen which was is seen on this specimen, for this is the contained in the same slab from Okdong adoral part of the phragmocone. with the preceding. Annuli are not yet This form agrees fairly well with Dis­ lined by tubular sheathes. The central coactinoceras multiplexum, but the less cavity is narrower than a half of the developed sheathes in the broad central siphuncular diameter at the adapical end, cavity and lunate cross section of the but it is expanded more than a half of cavity suggest that this is probably a the diameter at the other end. distinct species,although its denomina­ The third specimen from Hyeoleom is tion is postponed. a phragmocone 55 mm long; 5 camerae OCCllrrence: - The two specimens in found in the length of 20.5 mm. Its cross SHIRAKI collection were procured from (1) section shows that the shell is attached Tanggok and (2) North of Sinch'on, to the siphuncle at the broad more or Hwangji-ri, both in Sangjang-myeon, less flattened venter. The central cavity Samcheok-gun, Kangweon-to,South Korea, in the section is broad and lunate with probably either from the Tsuibon lime- convexity on the dorsal side. On the 230 Teiichi KOBAYASHI left side of the longitudinal section one side where sheathes are absent, is essen­ can see narrow camerae near the zone of tially an actinoceroid siphuncle. On the contact. There the septa are gently in­ other hand the siphuncular structure clined for some distance, but abruptly where the sheathes are developed on the geniculate near septal necks. Annuli are inner side reveals an endoceroid-like well developed, but no tubular lining is siphuncle, although the change from the as yet deposited in this siphuncle; central endosiphocone to the endosiphotube is not cavity relatively narrow. Episeptal de­ so sharp as in the Endoceratida. The posits are present on the ventral side in sheath-development is an example of paral­ camerae on the outer and posterior sides, lel specialization to the evolution of the while hyposeptal deposits are confined to Endoceratida which occurred in the Ac­ the middle part of the anterior side. The tinoceratida. camerate portion is preserved also on the In the Endoceratida the endosiphotube right side of the observer which is not except for the short anterior terminus is polished. closed by diaphragms or endosiphuncular In Discoactinoceras wuyangense CHEN segments in N athecoceras crassisipho­ and Lru the septal neck is of Armemoceras natum, A1anchuroceras wolungense and type, the nummulus shouldered and an­ Penhsioceras? sp. (KOBA Y ASHI, 1935, nuli are lined with tubular and conical 1947). In Cameroceras d. manitobense the sheathes as in this species, but in com­ successive lining of the anterior relic por­ parison with the thickness of the sheathes tion of the tube through growth yields the annuli are very broad. The siphuncle cone-in-cone structure in its endosiphotube is marginal but little mention is given of (TEICHERT and CRICK, 1974). In Disco­ its cross section. actinoceras multiplexum, however, the Occurrence;-The first and second speci­ endosiphocone and endosiphotube are mens were collected from Chinku-ri, filled up with the same kind of dirt. Okdong, Sangdong-myeon, Yongweol-glln, In the Endoceratida the camerate por­ Kangweon-to. The third specimen was tion was scarcely connected with the obtained from 1.5 km sOllthwest of Hyeo­ endosiphuncle where endocones were ac­ leom, Sangjang-myeon, Samcheok-gun, cumulated sheath after sheath, while in Kangweon-to, South Korea. the Actinoceratida any connection could be maintained between the siphuncle and Specialization of Discoactinoceras camerae through the connecting rings. In Discoactinoceras multiplexum and D. As the result of the preceding descrip­ d. multiplexum also it is known that tion it is emphasized as the most salient radial canals were extended from the point that the siphuncle of Discoactino­ central cavity and opened at the peri­ ceras is composed of a series of annuli spatium as in other actinoceroids, but in the outer side, but invaginated sheathes sooner or later the canals and annuli in the inner side which are conical like­ were largely lined on t:1eir inner side by endocones on the adoral side, but tubular tubular sheathes which were wavy at on the adapical side. The endosiphuncle first but became straight in longitudinal in the central part is a conical cavity section. Radial canals penetrated the which, however gradually merges back­ sheathes at some places, but evidently ward with a narrow central tube or endo­ the control of the camerate portion be­ siphotube. The siphuncle in the adoral came difficult for the soft animal through 684. Discoactinoceras and the Discoactinoceratidae 231 the growth of the sheathes. the camerae lost their importance. In some endoceroids, Proterocameroceras, As discussed already (1977), the Maru­ .Manchuroceras and Coreanoceras, for ex­ yam an or early Toufangian age is appro­ ample, the endosiphuncular blades cross ximately the Whiterock in North America the endocones at definite position. Al­ and the Llanvirnian in Europe when the though their nature and function are not first step of radiance has been advanced yet well known, they look incomparable of the Actinoceratida and Wutinoceras, with the radial canals of actinoceroids. Polydesmia and Ordosoceras were brought On the other hand it is interesting to see to birth in Eastern Asia. Then the the lunate cross section of the central Armenoceratidae and Ormoceratidae have tube in Discoactinoceras d. multiplexum developed there probably from Wutino­ that it is very much like the crescentic ceras in the middle Toufangian age when section of the endosiphotube of Man­ the Toufangkou limestone was deposited churoceras. Both of them have marginal in Koreo-Manchuria. Now this limestone or submarginal siphuncles whose endo­ is divided into three parts. Therefore I siphuncles are lunate in section with con­ have tried to find out the appearance of vexity on the dorsal side. Because the Discoactinoceras more accurately, but it development from the actinoceroid was in vain for there is still some dis­ siphuncle to endoceroid like siphuncle agreement in the tripartitions by OBATA which occurred in Discoactinoceras means and CHEN, although, CHEN (1976) suggest­ the increase of the shell weight and the ed the early Middle Toufangian age for ventral shifting of the center of gravity D. multiplexum. At any rate it is certain and at the same time the devaluation of at present that Discoactinoceras is one of the air-chamber for its life. Therefore the most specialized actinoceroids, insofar this specialization must have been related as the siphuncular structure is concerned, to benthonic adaptation. and it appeared sporadically some time Because the shell growth of the Nau­ during the middle Toufangian age and tiloidea advances as a rule from exterior survived by the end of the age or even to interior and in each element from a little later. apical to oral, the armenoceroid septa of Finally, I have pointed out long ago Discoactinoceras shows its derivation from (1929) that DiscosorllS resembles Disco­ the stock of the Armenoceratidae, but in actinoceras in the possession of endocone­ this stage of construction of the septa like sheathes, but its conch is quite dif­ and camerae the septal geniculation and ferent as it is a curved brevicone. Since the shouldered connecting ring show its than the order Dis:::osorida was greatly speciality of evolution. Until the growth clarified by FLOWER and TEICHERT (1957) stage of neck rings, however, the genus and it is known at present that such a was not far apart from many other ac­ structure occurs in certain genera of the tinoceroids. Judging from its camerae Westonoceratidae and Discosoridae, but and broad central cavity of siphuncle it the actinoceroid structure in the outer is presumable that the animal was cap­ part of the siphuncle is always absent in able of swimming in this stage as some them. Their end ocone-like sheathes de­ other actinoceroids. In the full grown veloped gradually from the lining of the stage, however, it became a vagile benthos nummuloidal siphuncle. Therefore this in view of the facts that the siphucle is another parallel specialization which became so heavy and at the same time took place in the Discosorida intermit- 232 T eiichi KOBAYASHI tently during the prolonged three Palaeo­ (1965) : Chinese Ce phalopod Fossils. Each zoic periods, from Ordovician to Devonian. Group of Fossils in China, 389 pp. 85 pI s . Before closing this article I record here CI-IEN, hi-yuan (1976) : Advances in the Ordo­ my sincere thanks to Assoc. Professor Itaru vician stratigraphy of North China with a brief description of nautiloid fossi ls. H A YAM! of the University of Tokyo for Acta Pal. Sinica, vol. 15, no. 1, p. 55- 73, his warm assistance for its preparation. pI. 1-3. -- and LI U, Geng-wu (1976) : North Chinese References rype nautiloids . In L u Yenhoo, CHU, Chao­ ling, CHI EN , Y i- yuan, ZH OU, Zhi-yi, CH EN, CH A:" C, W .T. (1964) : Ordovician System of Jun-yuan, LI U, Gen-wu, YO, ' 'Yen, CH EN, China. S ci. R ep. of Slratigl·. Can/. China. Xu and X u, Han-kui: Ordovician bio­ 161 pp., 1 table . stratig raphy and palaeogeography of CH AO , Chink-ke, LI ANG , I-Isi-ho, T sou, I-Isi­ China. M em. Nani

T ext-fig ure 2. of siphuncJe in pI. 31, fig . 5. a : annulus, c: central tube, g : septal genicuJation, r: radial canal, t: tubular sheath.

Explanation of Plate 31

F igures 1--1. Discoactinoceras mllltipleXll11l KOBAYAS HI. Two longitudina l sections, weathered surface and transve rse section. All reproduced from Plate 22, fi g ures 7a-d , KOB AYAS HI , 1929. Natural Size. PM 005l. Fig ure 5. Same species. Posterior part of longitudinal section in fi g . 1, four times m agnifie d from the holotype specime n to show septal geniculation near siphnucle and growth of an­ nuli and tubular sheathes in the siphuncJe . KOBAYASHI.' Discoactinoceras Plate 31

2 3 684. Discoactinoceras and the Discoactinocemticlae 233

ENDO, R. (1932): The Canadian and Ordo· uncular structure of an endoceroid. Japan. vician of Southern Manchuria. U.S. Nat. Jour. Geol. Geor., vol., 20, p. 13-lS, pI. 4. Mus. Bull. 164, 152 pp. 40 pI. map. -- (1966a): The Chosen group of South -- (1953) : A summary of the columnar sec· Korea. Jour. Fac. Sci. Univ. Tokyo, sec. tion in Manchuria. Proc. Seventh Pacif. 2, vol. 16, pt. 1, S4 pp. Sci. Congr., vol. 2, Auckland & Christ­ -- (1966b): The Chosen group of North church, p. 316-326. Korea and Northeast China. Ibid., vol. 16, FLOWER, R.H. and TEICHERT, C. (1957) : The pt. 2, p. 209-311. cephalopod order Discosorida. Paleont. -- (1977) : An occurrence of Ordosoceras in Contr. Univ. Kansas, Mollusca, '·01. 6, 144 lehol, Northeast China, and a note on the pp. Polydesmiidae. Tmns. Proc. Pal. Soc. Jap­ FOERSTE, A.F. and TEICHERT, C. (1930) : The an, N.S. no. lO7, p. 125-134, pI. IS, 19. actinoceroids of East-Central North Amer­ Lv Yen-ho (1975) : Ordovician trilobite faunas ica. Deniso7! Univ. BUll. Jour. Sci. Lab., of central & southwestern China. Palae­ vol. 25, p. 201-296, pI. 27-59. onto Sinica, n. S. B, no. 11, 463 pp. 50 pis. GRABAU, A.W. (1922) : Ordovician fossils from OBATA, T. (1965) : Ordovician nautioloid zones North China. Palaeontol. Sinica, ser. B, in North China. BUll. Aichi Gakugei Univ. vol. 1, fasc. 1, 127 pp, 9 pis. (Nat. Sci.), vol. 5, p. 50-56. KOBAY ASIII, T. (1929): Ordovician fossils SI-Il~IIZU, S. and OBATA, T. (1935) : New gen­ from Corea and South Manchuria. Japan. era of Gotlandian and Ordovician nau­ Jour. Geo!. Geogr., vol. 5, p. 201-296, pI. tiloids. Jour. Shanghai Sci. Inst., sec. 2, 27-29. vol. 2, p. l-lO. -- (1931): Studies on the Ordovician stra­ TEICHERT, C. and CRICK, R. E. (197'1): Endo­ tigraphy and palaeontology of North Korea siphuncular structures in Ordovician and with notes on the Ordovician fossils from Silurian cephalopods. Univ. Kansas, Pale­ Shantung. BUll. Geol. Surv. Chosen onto Contr. 7l, p. 1-3, pI. 1-3. (Korea), vol. 11, no. 1, 60 pp, 9 pis. TWENI-IOFEL, W. H., (Chairman) et al. ----'- (1935) : Restudy on Manchuroceras with a Ordovician Comm. (1954): Correlation of brief note on the classification of endo­ the Ordovician formations of North Amer­ ceroids. Jour. Geol. Soc. Tokyo, vol. 42, ica etc. Bull. Geo!. Soc. Am., vol. 6, p. p. 736-753, pI. 21. 247-29S, char. 2. -- (19,10) : Polydesmia, an Ordovician actino­ WADE, M. (1977): Georginidae, new family of ceroid of Eastern Asia. Japan. Jour. Geol. actinoceroid cephalopods, Middle, Ordo­ Geogr., vol. 17, p. 27-44, pI. 3-5. vician, Australia. Mem. Queensland Mus., (1947) : _-\n observation on the endosiph- vol. IS (1), p. 1-15, pI. 1-17.

Place Names C: China, K: Korea

Bantatsusan, Mandalsan IJ)E~LU (K), Changp'yong-dong ~J:5l'1/liJ (K), Chihli @~ (C), Chinku-ni $Ji'~H! (K), Chiushukou :f};WiiI; (C), Ch'osan ~LiJ (K), Dawan *~ (C), Dongjeom-ni mJiSH! (K), Hopei iDJ~t (C), Hwangji-ri 1ti!l!H! (K), Hyeoleom i\iIc (K), Kangweon-do ITi*ill (K), Kangyao /i[ili! (C), Kechuang &Jf1: (C), Kuniutan !liilj:o~ (C), Hsiaofankechuang 'H~~4?J1: (C), Leichuang ~:1± (C), Liangchiashan ~*LiJ (C), Liaoning ~~ (C), Lincheng j:i&;:!8t (C), Machiakou .~*iiI; (C), Maru- yama, Hwansan:}LLiJ (K), Miaopa M~ (C), Nam-myeon moo (K), Nanso, Namjang fff:1± (K), Neichiashan 3t*LiJ (C), Ok dong :Killll (K), Niuhsintai lj:o.c",il' (C), Patou i\1lIi (C), Peianchuang ~tltJ1: (C), Samcheok -=:~!f;:(K), Sangdong-myeon J:JlnIii (K), Sangjang-myeon J::N:OO (K), Sinch'on ~f;j (K), Ssuyen I19Ill (C), Tanggok ~~ (K), Tangshan Jl!fLiJ (C), Tapu *~ (C), Toufangkou JiJ:fHtli (C), P'yeongan-bukto 3f:tc~tifi (K), Unkaku, Unhak ~~ (K), Wushan :ii\:LU (C), Wuting .lim (C), Yehli l'i1'H! (C) 234 Teiichi KOBAYASHI

Discoactinoceras 2:: ~ft Discoactinoceratidae - Discoactinoceras Ii. Huroniidae ~ Polydesmiidae t;::.l\.;h,G;h, "(1,'f.:iJ~, {ll;:'ll!'Ij;H;::W~Ii.~jq15~"t:, l~t;::Ii.P:ljq15M2::Mfj;J:t7.> Jt.!tkJ'i'~I::t' 7.>,~ "t: J:~r.::::ft 2:: Ii.~ < ~ '? "( 1,'7.>. -=t Q)~~MIi. Armenoceras ~ "t: Armeno­ ceratidae 2:: IJ'i]-VlJt;iJ' G :$fir. L. "( :lief.: 2:: ~ *- G;h, 7.> iJ~, ~~fi.~ltJiiJij"t:li~j]lilB9"t:, ji!ij!liffiffl)"t: ;E,t;::~;h,rJIl-?"(, ~ ~ S *;jj('i'~ L."( 1" 7.> • .:.;h,G Q)!l'ifM:.iJ'G t ~ftfi.ft!!Q)~f4 2:: ~ I), ~jq 15M. i¥.jlji}J!fj1[")~*:2 v!l '/ 3 :/

Explanation of Plate 32

Figures la-b. Discoactinoceras cf. multiplexum KOBAYASHI. Longitudinal and transverse sections of adoral part of a phragmocone. x P/2 Hwanji-ri specimen. PM 4296. Figures 2a-c. Same species. One longitudinal and two transverse sections from 13 mm and 12 mm respectively from anterior and posterior ends of a siphuncle. xl. Tanggok speci­ men. PM 4297. Figure 3. Discoactinoceras okdongense KOBAYASHI, sp. nov. Longitudinal section of siphnucle. Natural size. Second specimen of Okdong. PM 4298. Figures 4a-c. Same species. Two longitudinal and one transverse sections. Natural size. Hyeoleom specimen. PM 4299. Figures 5a-e. Same species. Two longitudinal and three transverse sections of the holotype siphuncle. Natural size. Okdong specimen. PM 4300. Repository: University Museum, University of Tokyo. KOBA YASHI: Discoactinoceras Plate 32 Trans. Proc. Palaeont. Soc. Japan, N. S., No. 109, pp. 235-258, pIs. 33-35, April 30, 1978

685. PHENOTYPIC SUBSTITUTION OF GAUDRYCERAS (A CRETACEOUS AMMONITE)*

HIROMICHI HIRANO

Institute of Earth Science, School of Education, Waseda University, Shinjuku, Tokyo 160

Abstract. The mutual relations among three nominal species, Caudryceras denseplicatum, C. intermedium and C. tenuiliratum from Japan and Sakhalien are exam­ ined. C. denseplicatum and C. intermedium are here explained as a sexual dimorphic pair from the facts that they coexist, they occur in the same stratigraphic range and a constant numerical ratio of the specimens is kept for the duration in addition to their morphogenetical resemblance. They should be degraded to C. denseplicatum var. denseplicatu7ll and C. d. var. intermedium respectively. Some main characters of C. tenuiliratum are common to those of var. densepli­ catum and var. intermedium. The numerical ratio of the specimens of C. tenuili­ ratum to those of C. denseplicatum var. deseplicatum+ C. d. var. intermedium his­ torically changes in the same pattern in Obira, Hokkaido and Naibuchi, Sakhalin. Three possible explanations on the relations of C. tenuiliralulll with C. d. var. denseplicatum and C. d. yar. intermediul1l are discussed and transient polymorphism seems to be the most reasonable. Then C. tenuiliratul1l is degraded to C. dense­ plicatum var. tenui liratu m.

Introduction spectively. No character was significantly changed in each variety during the life Ammonites have been looked upon as period of the species. They are very interesting and favourable material for similar to one another, although a few evolutionary study, but the detailed characters are different as mentioned by evolutionary mode has not always been MA TSUMOTO (1941). The species occurs established. The material which I deal fairly commonly in Sakhalien, Japan, with is a species of Caudryceras which Madagascar and some other areas. flourished from the Turonian to Maastri­ The purpose of this paper is firstly to chtian of the late Cretaceous. It includes clarify the mutual relations of these three three nominal species, C. denseplicatu1Il varieties and secondly to obtain an in­ (jIMBO. 1894), C. intermedium Y ABE, 1903 formation about the adaptive strategy of (emend. SHIMIZU, 1935) and C. tenuili­ ammonites which flourished in the Creta­ ratum Y ABE, 1903, but I here regard ceous. them as conspecific for the reasons which I express my gratitude to Prof. Tatsuro mentioned later. In the present paper MA TSUMOTO, Dr. Itaru HAY AMI and Dr. they are called var. denseplicatll7n, var. Kazushige TANABE for their discussion intennediu17l and var. tenuiliratum re- and criticism. Prof. Terumi MUKAI, Dr. * Received July 4, 1977: read June 14, 1975 Tsuneyuki YAMAZAKI and Dr. Osamu at Morioka and Jan. 30, 1976 at Kawatabi. YAMAGUCHI gave me instructive advice 236 Hit'otnichi HIRANO

on genetics. Prof. Anthony HALLAl\'! I I kindly read the manuscript and gave E140 148 me some suggestions. Prof. Tokio SHlKAMA. Prof. Tetsuro HAl'iAI, Dr. Ikuwo OBA T A, Dr. Takashi HAMADA, + Dr. Kiyotaka CHINZEI and Dr. Noriyuki + IKEY A gave many helpful suggestions. Among the studied samples, those from Sakhalien and part of Hokkaido were +46 obtained by Prof. MATSUMOTO and + have been generously loaned for this study. These and several other speci­ mens kept in the University Museum of the University of Tokyo have been on loan by courtesy of Prof. HANAI. This study was financially supported partly by the Science Research Fund of the Ministry of Education, Science and Culture (No. 0 074202 for 1975, No. 174269 for 1976), the Matsunaga Research Grant and Prof. o 100 200Km , I MATSUMOTO'S Grant. Miss Mutsuko HAYASHIDA and Mrs. Yukiko HIRANO Fig. 1. Map showing the fossil locali- assisted me in various ways. ties. N: Naibuchi, K: Kawakami, S: Saku, R: Obira, A: Ashibets and Ikushumbets, Y: Yubari and Oyubari H: Hobets, T: Tomiu- Material and method chi, U: Urakawa. The samples studied in this work were Besides the material from the areas obtained from the Naibuchi area in mentioned above I examined some speci­ Sakhalien and the Obira, Ashibets and mens obtained from the Kawakami area Tomiuchi (=Hetonai) areas in Hokkaido in Sakhalien, the Saku. Oyubari, Ikushum­ (Fig. 1). Those from the Naibuchi and bets, Hobets and Urakawa areas in Hok­ Obira areas are large in size and were kaido and the Uwajima area in Shikoku obtained in stratigraphic order. Therefore which are kept in the University Museum they are suitable for the statistical of the University of Tokyo and Kyushu examination. The samples are well pre­ University, although they are not directly served in hard calcareous nodules (with quoted. For the specimens from overseas diameter about 30 cm), though the body areas I depended on the published papers. chambers are not always complete. Here The whorl of Gaudryceras is planispiral. specimens derived from one nodule are The morphology can be expressed graph­ considered as one sample. For the geol­ ically by projection of two planes which ogy of these areas and the locality cross perpendicularly to each other. Be­ records including associated fossils see cause the mode of coiling and the relief MATSUMOTO (1942, 43), MATSUMOTO ed. of surface sculpture are often considered (1954), MATSUMOTO and OKADA (1973), as the specific criteria in Gaudryceras MA TSUMOTO et al. (in press), TANABE et and the tangential section enables us to al. (1977) and HIRANO et al. (1977). measure these two characters, the tangen- 68.5. Phenotypic substittaion of Gaudrycems 237 tial section was employed for the study ysis is the future problem with the of relative growth. The mensuration revision of classically described species was done under Nikon profile projector in the world. Here I show the strati­ V -16 and the suture lines were drawn graphic distribution and the number of using Wild stereoscope. specimens in each zone of the sequences of the Naibuchi and the Obira areas Distribution of G([lUZnlCeras (Table 1). Var. denseplicatum and var. intermedium appeared in the Inoceramlls So far as available literature is con­ labiatus zone of the Turonian and continue cerned, about thirty species of Caudry­ to the I. amalwsensis zone of the Santo­ ceras have been reported from various nian (Obira) and the I. japoniCZls zone of localities of the world. The first appear­ the Santonian (Naibuchi), and their ex­ ance of this genus is in the Cenomanian tinction occurred in the early Campanian of India (KOSSMA T, 1895; COLLIGNON, (MATSUMOTO, 1942, 59a). On the other 1956) and J apan-Saghalien (MATSUMOTO, hand, var. tenuiliratum appeared in the 1942), though a precise record in the I. uwajimensis zone of the Coniacian, former region is not available. Concern­ continuing at least to the I. japonicus ing the latter, although the stratigraphy zone of the Santonian. The upper limit is very well established, the occurrence of this variety is early or middle Cam­ is not frequent. panian (MATSUMOTO, 1959a), and the Only three nominal species have been number of specimens seems to increase confirmed from the Turonian, C. dense­ with time. plica tum, C. intermedium and C. varagur­ I examined the chang'" of then umerical ense. The first and second occur in ratio of var. intermedium to var. dense­ the Lower Turonian of J apan-Sakhalien plica tum in the sequences of Naibuchi (jIMBO, 1894 ; SHIMIZU, 1935; MATSUMOTo, and Obira (Fig. 2). The numerical ratios 1941, 43, 59b) and the third was reported of the specimens of these two varieties from the Turonian of India (KOSSMAT, do not show any significant differences 1895) and Angola (HOWARTH, 1965), with (Table 2): the hypothesis of uniform ratio little stratigraphic information. A species is not rejected. comparable with C. intermedium is known The numerical ratio of var. tenuili­ from the Turonian of Angola (HOWARTH, ratum to var. denseplicatllln+var. inter­ 1965). In the Coniacian and Santonian medium seems to increase gradually with Calldryceras is widely distributed. The time (Fig. 3). The ratios in the two extinction of Caudryceras occurred in the sequences, Naibuchi and Obira. are exam­ Maastrichtian. ined by chi-square test (2 X 2 contingency Through this specified time Caudryceras table) to know whether the zone by zone may be. most abundant in the Japan­ ratios equal to each other or not. The Sakhalien area. The biostratigraphical results show that there are no significant distribution and the mode of occurrence differences between the two sequences have been preliminarily reported by (Table 3) and that the patterns of the MATSUMOTO (e. g., 1942, 43, 59b; ed., transition of the ratios in these two areas 1954). The specific diversity of Caudry­ are equal to each other. ceras, however, is not high there. This Furthermore, in the field these three phenomenon is interesting in view of the varieties are commonly fonnd in the same phylogeny of Calldryceras, and its anal- nodule or one exposure. Although the 238 Hiromichi HIRANO

Table 1. Stratigraphic distribution of C. denseplicatum var. denseplicatum, var. intermedium and var. tenuiliratum in Obira, Hokkaido and Naibuchi, Sakhalien. Number of specimens Local Geological Zone of m.y. Obira Naibuchi stratigraphic age Inoceramus division alb 1 c 1 die alb 1 c 1 d 1 e

Campanian 1 orientalis 01 01 01 01 01 01 01 01 01 0 Mh7 76 91 8 19 36 100 Mh6p japonicus 0 0 0 19-1- 01 1i 0 16 17 11 Mh6a-/3 Santonian n 4 41 11 34 Mh6a2 amakusensis 0 1 21 22 19 0 -1\-8 1 Mh6a1 -82 ~I mihoensis y 01 01 40 40 3 21 01 21 41 0 Mh5 Coniacian 1 1 uwajimensis 61 11 31 10 1 11 31 31 71 1 Mh4 88 1 teshioe:nsis 31 11 31 35 11 01 01 1 Mh3 1 ._- Turonian hobetsensis 91 21 49 60 01 01 11 1 Mh2 1 I I - labiatus 01 0\ 5\ 5 11 01 01 1 Mh1 94 Cenomanian 1 concentricus MhO 1 1 1 1 1 1 \ I a: var. densepllcatum, b: var. mtermedzum, c: Immature specImens of var. denseplicatum and/or var. intermedium, d: a+b+c, e: var. tenuiliratum. n: naumanni, y: yokoyamai

Zone Ob ira Naibuchi Age of m.y. lin oceramus Ratio Number Ratio Number Camp an. orientalis ~ var. d 76 - Q var. i .....-. japonicus "x'XXX2to! • , Santon. ------. , am akusensi 5 • ~ I • 82 - ~ mihoensis • I Coniac. uwajimensis ...... --. I • I 88 - teshioensis ~ • I ~ Turon. hobetsensis ""-"

t I labiatus • 94 - J Cenoman. concentricus 0 1.0 0 5 10 0 1.0 0 5 10

Fig. 2. Chronological changes of the numbers of the specimens of var. denseplicatu1ll and var. intennedium and the numerical ratios of the latter to the former (95% confidence interval is shown by a bar). 685. Phenotypic substitution of Gaudryceras 239

Table 2. Chi-square matrix with Yate's correction (2 x 2 contingency table) on the ratio of the number of the specimens of var. intermedium to that of var. denseplicatum, from the Upper Cretaceous of Naibuchi (upper) and Obira (lower). Data same as Table 1.

Mh6 Mh6 Mh6 Mh6 Mh5 Mh4 Mh3-1 8:9 0:1 4:4 1 : 0 0:2 3 : 1 0:2 Mh6

Mh6 0.01 Z20 . 05("=I) = 3.84 Mh6 0.09 0.01

Mh6 0.00 0.00 0.01

I Mh5 0.27 - 0.23 0.19 I Mh..! 0.20 0.05 0.04 O. 70 I 0.75 Mh3-1 0.27 - 0.23 0.19 - 0.75 I I amak. miho. uwaj. teshio. hobets. labia. 1:0 0:0 1 : 6 1 : 3 2:9 0:0 amak.

miho. -

uwaj. 0.38 -

teshio. 0.05 - O. 14

hobets. 0.36 - O. 19 O. 19 labi. - - I - - - I

Zone Geological of Local o bira Naibuchi age Inoceramus subdivision ...... japonicus Mh6A I • I Santonian Mh6ClC.A --- .---...... amakusensis .Mb..6.ct2 .....--.... Mh6oc:1 I • I mihoensis Mh5 ...... • I Coniacian uwajimensis Mh4 I • I I • I teshioensis Mh3 .-. .-...... ------...... -"1 Turonian hobetsensis Mh2 •• .- .. - .... ----_. --_ ..... -- ...

.-...... - -I labiatus Mh 1 0 0.2 0.4 0.6 0.8 to Q---0.2"--0.4---0.6---0:8 1.0 Fig. 3. Chronological change of the numerical ratio of var. tenuiliratum to the three varieties in the number of specimens (95% confidence interval is shown by a bar or a dashed line) . 240 Hiromichi HIRANO

Table 3. Chi-square matrix with Yate's correction (2 x 2 contingency table) on the ratio of the number of var. tenuiliratum to that of the pair of var. denseplico.tulll and var. intermedium between the samples from Obira and Naibuchi. Data same as Table 1. Mh4 ~ Naibuchil Mh6,B I Mh6a-,B I Mh6a1+ a2 1 Mh6a2 Mh6a1 Mh5 Obira ______100: 36 11 : 17 35: 28 34: 19 1 : 9 0:4 1 : 7 japonicus 19 : 0 I 5.15 1 15.0 ------~------+------.------,------amakusensis 19: 221 0.87 I 0.19 0.52 2.30 3.06 mihoensis 3 : 40 0.27 I uWajimensis 1: 10 I 0.27 clear distinction between var. dense­ parts of the body relative to that of the plica tum and var. intermedium in the body is in a certain functional relation. immature stages is impossible, as will be called allometry, and is expressed as mentioned later, some of the immature y=(3x" (where y represents the size of specimens which have hitherto been re­ a particular organ or a part of the body; garded as C. denseplicatum are assumed (3 the relative size of the organ at its to be var. intennedium and the rest are first appearance; x that of the total body var. denseplicatum from the examination or a part of the body; and lX the rate of of the position of the nepionic constric­ growth of the organ y) (NOMURA, 1926; tion. Thus, var. denseplicatum and im­ HUXLEY, 1932). GOULD (1966) designated mature var. intermedium are coexistent. the term allometry as the differences in Adult individuals of var. intermedium proportions correlated with changes in sometimes occur exclusively and therefore absolute magnitude of the total organism the habitat may be somewhat different or of the specific parts under consider­ from those of the immature var. inter­ ation. Ideally, the growth pattern of an medium and other varieties. A fully ammonite is isometric and the pattern is grown up and large specimens of var. recognized as a logarithmic spiral (THOMP­ intermedium, however, independently forms SON, 1917; HUXLEY, 1932; OBATA, 1959. one nodule (the size of a fully grown up 60, 61, 65). The method of mesnuration specimen is nearly the same as that of a is the same as that described in HIRAKO common nodule) and therefore the asso­ (1975). ciated fossils with the adult variety in a The growth pattern of the whorl of nodule are rare. It is uncertain whether var. denseplicatum is characterized by the this mode of occurrence depends on high rate of the growth of radius length physical and! or chemical or biological to the spiral in comparatively later stages reasons. Var. tenuiliratum often coexists as shown in Fig. 4 (Compare it with that with var. denseplicatum and assumed im­ of var. tenuiliratum in Fig. 10 of this mature var. intermediulIl. paper and fig. 3 in HIRANO, 1975). The suture line shows little variation and is

Characteristics of var. denseplicatlllll expressed as ELU2U1Is in terms of the and var. intennediu1n formula by KULLMAN and WIEDMANN (1970) (Fig. 5). The surface of shell is Ontogeny: Generally, the growth of covered by widely interspaced thin and 685. Phenotypic substitution of GaudTycem8 241

R

3 o

10.0

5.0

• R4018b N= 3

o R 2643p N 2 1.0 o e =

o• I •"0 I 0.5 iii 0

Fig. ,1. Example of the growth pattern of the radius length (R) to the spiral (0). Samples are from the teshioensis zone of Obira (R26.13p: var. denseplicatu11l; R101Sb : var. denseplicatu11l and/or var. inter11ledium).

comparatively high radial subcostae from tenuiliratum (HIRANO, 1975), and especially the first whorl to the early half of the the first, nepionic constriction, is situated third whorl. After the stage, numerous' at a constant position (Table 6). coarse and weakly sinuous subcostae C. denseplicatum var. intennedi1l11l was (Tables 4, 5; See table 11 of tenuiliratum at first described by Y ABE (190~) as a in HIRANO, 1975) appear, and branching variety of C. tenuiliratum and regarded and insertion of these subcostae arise on by SHIMIZU (1935) as a distinct species. the lateral to the ventro-lateral side of After that it was treated by MATSUMOTO the fourth to the fifth whorl. At about (1959b) as a subspecies of C. de71seplicatum. the sixth whorl the costae appear and As mentioned in the previous chapter, continue later. They describe a sine the variety under consideration is coex­ curve in cross section and the inters paces istent with var. denseplicatum and there­ become narrower with growth. The body fore the sub specific relation between them chamber occupies a little less than 360' is unlikely. in spiral angle, although the estimation The morphological characteristics of is approximate owing to the difficulty var. intermedium are the same as those in recognizing the peristome. The ventral of var. denseplicatum to the 5th or 6th shell is composed of three layers and the whorl and the differences between them dorsal shell is of two layers as the outer are not detected by the observation and layer wedges out at the umbilical seam. the biostatistic examination(Figs. 6. 7). The This variety has a constriction like var. growth ratio of the radius length to the 242 Hiromichi HIRANO

G

M

p

o

Fig. 5. Sutural ontogeny of var. denseplicatum. A-G: H2157, from Mh61', Naibuchi, Sakhalien. A: 180· from the protoconch. B: 2.5 th whorl. C: 3.5th whorl. D: 4.5th whorl. E: Just 5th whorl. G: Just before 6th whorl. H-N: H2153, from Mh61', Naibuchi. H: 3/4 whorl. I: Just before 3rd whorl. J: 3.4th whorl. K: 3.7th whorl. L: 4th whorl. M: Just 5th whorl. N: 5.5th whorl. 0: H023b, from Onnenai, Hokkaido. 5.25th whorl. P: var. tenuiliratum, H5022, from Kawa-kami. Just 6th whorl. The horizontal bar indicates 1 mm.

spiral, however, increases after the 5th one whorl later the costa describes a or 6th whorl and we can distinguish them sine-curve in cross section. if the specimens are larger than the Geographic and chronologie variation: growth stage. Further, the costae appear The geographic variation of var. dense­ at about 6th or 8th whorl, and continue plica tum is very little like that of var. to one or more whorls, and the adult tenuiliratum (HIRANO, 1975) and no sig­ individual becomes very large (diameter nificant differences are confirmed about 30 cm±). The cross section of each costa the measured characters among the pop­ is quadrate in the early stage and is the ulation samples from Sakhalien and Hok­ same as that. of var. tenuiliratulIl. About kaido. As an example the growth ratio 685. Phenotypic substitution of GaudTycems 243

Table 1. Height of subcosta (mm) at the three different ontogenetic stages, the 4th, the 4 1/2 and the 5th whorl, of var. denseplicatum and/or var. intermedium. Samples are from Obira.

Age the 4th the 4 1/2 the 5th

.:: N 7 7 7 .~ .:: x 0.019 0.041 0.078 .8 amakusensis SD 0.011 0.028 0.034 ~ [f) OR 0.008-0.036 0.013-0.096 0.028-0.098

N 1 mihoensis x - SD - OR 0.067

N 2 3 .~ u unknown* x 0.064 0.096 .~ .:: SD 0.036 0.066 0 u OR 0.038-0.089 0.040-0.169

N 3 3 uwajimensis x 0.076 0.128 SD 0.053 0.095 OR o. 0-12-0. 137 0.054-0.236

N .;I 5 teshioensis x 0.018 0.087 SD 0.021 0.027 OR 0.031-0.077 0.061-0.129

.:: N 6 6 6 .~ .:: hobetsensis x 0.014 0.035 0.059 0 1-0 upper ;::J SD 0.013 0.047 0.019 E-< OR 0.007-0.037 0.011-0.131 o. 037 -0. 071

N 7 7 7 hobetsensis x 0.010 0.027 0.090 lower SD 0.009 0.015 0.037 OR 0.003-0.029 0.011-0.055 0.055-0.166 * The detailed age is not determined. N: sample size, x: mean value, SD: standard deviation, OR: observed range.

of the radius length to the spiral of some variety is distribu ted as far as Madacas­ Santonian samples and the results of the car and differences have not been detected statistical examinations are shown (Tables between the specimens from the Japan­ 7, 8). Concerning the suture, no~ only Sakhalien area and Madagascar, although the basic elements but also the. detailed they have not been quantitatively analysed. parts show no geographic changes. This As has been recognized previously, any 244 Hirornichi HIRANO

Table 5. Number of lirae on a quarter Table 6. Position of the nepionic constric­ of whorl of var. denseplicatum, tion of the pair of var. densepli­ counted at the umbilical should­ catum and var. intermedium ex­ er, at some ontogenetic stages. pressed by the angle between the An example is shown by the constriction and the protoconch Sample N22Z from Naibuchi. aperture. Samples from Obira.

Stage Mean S.D. N Stage N 7J S.D. 3 3/4-4th whorl 20.3 6. 1 3 naumanni zone 5 355°26 1 29°45' 4 -4 1/4 23.7 4.9 3 amakusensis zone 2 355°15' 7°26' 4 1/,1-4 1/2 21. 7 2.5 3 hobetsensis zone 11 365°06' 6°17' 4 1/2-4 3/4 17.0 1.4 2 4 3/4-5 18.3 2.1 3 cation of suture, modification of surface 5 -5 1/4 20.8 1.3 4 ornamentation and growth pattern of 5 1/4-5 1/2 21. 3 4.0 3 whorl, and the change of position of 5 1/2-5 3/4 17.0 0.0 2 nepionic constriction did not arise, and it follows that this evolutionary mode ex­ particular chronological transition of hibits a morphological homeostasis. An morphology such as increase or decrease example is shown by the growth ratio of of some quantitative characters (e. g., the radius length to the spiral (Fig. 8). protoconch size), complication or simplifi- The mean values of the figured samples

40.0 mm o 20.0

10.0 o. ~ . .~ . 5.0 • 0.: ••. 1 . it•• •• j o intermedium .~i appearance of rib .1 "* 1.0 .1 • denseplicotum o appearance of rib I I' I I • Q5 .. ,II •••

0.50 2 4 6 8 10 12 14 -n; Fig. 6. Growth pattern of the whorl height to the spiral angle in var. intermedium and var. denseplicatum. Var. intermedium: 13849, loco N332b, Mh6a, Naibuchi. Var. denseplicatum: H2158-1, 2, 3, loco N22Z, Mh6 {3, Naibuchi. 685. Phenotypic substitution of Gaudryceras 245 0.1602 0.1370 0.1236 0.1505 Here I test the randomness of this amkusensis Zone series by a runs test. The minimum 8 o before 97(. value is 0.1364, maximum is 0.1774 and 6 therefore the middle is 0.1569. Let the ~ after 97(. value larger than the middle value ex­ 4 press a and smaller as b. Now the com­ 2 position of the run is as follows. -lower horizon upper horizon~ 0r-~~~~-L~~--~~ __~ 12 Composition of run: a a a b b a a a a a b a a b b b hobetsensis Zone Run number: 3 2 5 1 2 3 Here we can get the total number of the runs, U =6, lOas and 6bs. In the table of the runs test of randomness (one side 2.5,%') the rejection areas are less than four and larger than thirteen, and U is out of these areas. Thus we can con­ clude that the hypothesis of randomness o N is not rejected. d 0 o Var. intermedium cannot be distin­ Fig. 7. Histogram of the growth ratio guished from var. denseplicatum until the of the radius length to the spiral (in the specimen shows mature characteristics. stages before and after 9 rr) of the pair of Thereupon I studied and compared some var. denseplicatum and var. intermedium characters in more details. from Obira. Sutural ontogeny: No significant dif­ in Fig. 8 are as follows in ascending ference is detected (Figs. 5, 9). order: Position of the nepionic constriction: 0.1774 0.1676 0.1639 0.1364 0.1529 0.1712 The frequency distribution is bi­ 0.1715 0.1751 0.1588 0.1616 0.1564 0.1582 modal (Table 9). Although the

Table 7. Growth ratio of the radius length to the spiral angle after the 9rr stage in some Santonian samples of the pair of var. denseplicatum and var. intennedium.

- SO" Sample N a±to,o5.vN SO" O.R.

Naibuchi (j) 3 O. 1374±0. 0083 0.0045 O. 1324-0. 1412 Obira (a) 10 O. 1461 ± 0.0158 0.0224 0.1054-0.1774 Obira (n) 3 O. 1505±0. 0134 0.0073 0.1442-0.1585 Ashibets (y) 2 O. 1693±0. 0520 0.0171 0.1572-0.1814 Tomiuchi (n) 2 o. 1533±0. 0540 0.0177 0.1407-0.1659 j: japonicus zone, a: amakusensis zone, n: naumanni zone, y: upper part of yokoyamai zone. N: number of measured specimens, a: mean of growth <;; ratios, ~"=: standard error, SO": standard deviation, O.R.: observed range. vN 246 Hiromichi HIRANO

Table 8. Differences of the growth ratios among five Santonian samples of the pair of var. denseplicatum and var. intermedium. (Data same as Table 7).

Sample Na(j) Ob(a) Ob(n) As(y) To(n) Naibuchi (j) * 1. 1331 2.6439 (3.3173) 1. 6103 Obira (a) 0.3234 * 0.3261 1. 3659 0.4234 Obira (n) 1. 1102 O. 1,181 * 1. 7858 0.2602 Ashibets (y) 1. 4769 0.5873 0.7705 * 0.9207 Tomiuchi (n) O. 7162 0.1796 0.1120 O. '1598 * Right upper: results of t.test. When there is a significant difference between the variances, Welch's method is, applied. Significant result at 5% level is indicated by. ( )., Noone is significant at 1% level. Left lower: Coefficient of difference.

Geological Zone of Growth ratio age Inoceramus japonicus N=3 I • I Santonian, I N~3 I amakusensis • N=4 I • I 'N=6 mihoensis, ...... -.. N = 2 Coniacian I • I uwajimensis •

• N=4 teshioensis I • I I Ni4 I N=7 I • I Turonian t---+--1 N=7 hobetsensis • N=2 I • I • N=3 I • I labiatus 0.10 0.12 0.14 0.16 0.18 0.20

Fig. 8. Chronological change of the growth ratio of the radius length to the spiral (after the:stage of 9 n:±) in the pair of var. denseplicatum and var. intermedium from Obira. The mean value and the 95% confidence interval are shown. The black circle without a bar indicates a sample composed of one specimen.

boundary cannot be set objectively, The unfavourable preservation of ,in general the position of the char· inner whorl of var. intermedium actor, of var. denseplicatum is at impedes the confirmation of this the later stage (e. g., Sample As- relation (The preservation of inner 1144: N=5, mean=368.95°, S. D.= whorls of large specimens are 4.20°) and tfi~t of var. inten;iedium ushaily unfavourable). is at the earlier stage (e. g., Sample Number of sub costae : No difference As-1129a: N=l, Angle=340.700). is detected. 685. Phenotypic substitution of Gaudryceras 247

Table 9. Chi.square test on the frequency distribution of the position of Nepionic constriction of var. dell­ seplicatum and/or var. illterllledi­ um. Sample is of the hobetsensis zone in Obira. Class Oi Ei

x-3s~x-2s 4 0.24 x-2s~x-s 0 1. 49 x-s ~x 0 3.75 .., x ~x+s 2 0. --I;) x+s ~x+2s 0 1. 49 x+2s~x+3s. 5 o. 24 N=l1 10.97

X2 = 163.40 > X20.05("=3) = 7 .8147 Size of the adult shell: Clearly distin­ guishable. Var. intermedilllil attains more than 30 cm. in diameter but var. denseplicatum does at . most Fig. 9. Sutural ontogeny of var. inter· medium. 13849, loco N332b, Mh6 a, Naibuchi. 20cm. A: 5-5.5 th whorl. B: 5.5-6 th whorl. C: Stratigraphic distribution: The strati­ 6-6.5 th whorl. The horizontal bar indicates graphic distribution of var. inter­ 1mm. medium is the same as that of var. denseplicatum and if one increases Height of sub costae : No difference is in the number the other also does detected (Table 10). so. Ratio of the height to the width of Geographic distribution: Var. inter­ subcosta: No difference is detect­ medium coexists with var. dense­ ed (Table 11). plicatum world-widely. In some Growth ratio of the radius length to areas which have been preliminarily the spiral: It is very difficult to studied only one of them is re­ detect the difference in the stages ported. before the costae appear (Figs. 6, 7). Discussion: As described above, var. Shape of costa: Usually distinguish­ denseplicatum and var. inter71ledilllll are able (see Plates). hardly distinguishable from each other

Table 10. An example of the height of subcosta (mm) at three defined stages in var. dellseplicatum and var. interllledium. Samples are of Santonian from Ashibets. The results of t-test are non significant in al1 stages.

var. denseplicatum var. illtermedium Stage As-1140 (N=2) As-1129 (N=l) t·test mean S.D.

the 4th whorl 0.014 0.004 0.008 1. 288 4 1(2 0.031 0.012 0.016 1. 010 the 5th whorl 0.073 0.019. 0.048 . 0.078 248 Hiromichi HIRANO

Table 11. Examination of the ratio of the height to the width of subcosta between var. del1seplicatum and var. intermedium. Samples are of Santonian in Ashibets. The results of t·test are non significant in all stages.

var. denseplicatum var. intennedium Stage As-11M (N =5) As-1129 (N = 1) t-test mean S.D.

the 5th whorl o. 189 0.083 o. 163 0.284 5 1/2 o. 284 0.053 o. 272 o. 194 the 6th whorl 0.333 0.054 0.403 1. 172 until they attained the adult condition. or var. intermedium is the phenotype of The close morphological resemblance and dominant homozygote plus heterozygote. the fact that they coexist geographically In some other cases such a dimorphism and chronologically suggest they are may be controlled by a kind of chromo­ conspecific_ We cannot expect the rela­ some aberration like inversion. The re­ tion of twin species (SIMPSON, 1961) for lations between phenotypic polymorphism this phenomenon under such conditions and chromosome aberration and the mentioned above. Homeomorphy is influence of chromosome aberration are known in various ammonites but even in discussed by many geneticists (e. g., such a case the suture, which has close OSHIMA et aI., 1974; DOWDESWELL, 1970)_ relation to their soft parts, is commonly The polymorphism maintained by allelic distinguishable, and as has been known genes which are associated with the by the studies of SCHINDEWOLF (e. g., inversion is exemplified or inferred in 1954) and KULLMAN and WIEDMANN (1970) some living mollusks (e. g., CAIN and the suture is a genetically very stable SHEPPARD, 1954; KOMAI and EMURA, 1955). character. The essentially similar pattern The mechanism of this phenotypic of rise and fall of these two phena and polymorphism is nearly impossible to the sufficiently uniform numerical ratio know, and similarly the distinction be­ indicate the likelihood that they belong tween the balanced polymorphism and to one and the same species. the sexual dimorphism is certainly difficult The simultaneous occurrence of several in this case. The proved dimorphisms, discontinuous phenotypes or genes in a however, of which mode of ontogeny is population, with the frequency even of hardly distinguished up to the adult and the rarest type higher than can be adult size shows differences, in the nat­ maintained by recurrent mutation, is ural world, are usually case of sexual known as polymorphism (MA YR, 1970). dimorphism, and the difference of the Examples of polymorphism are numerous adult size between male and female has in living species. Is this case a sexual been exemplified in ammonoids (e. g., dimorphism or other type of dimorphism P ALFRAMANN, 1966, 67, 69). like a balanced polymorphism? Thus I consider the case of sexual If this is a balanced polymorphism, the dimorphism_ Here, I note the ratio of characteristic differences between the the two sexes 0 and ~ is 1: 1 as seen two phena have possibly arisen from a in the living Sepiidae (YAMAMOTO ed., pair of alleles of which one gene is 1973) and many other organisms, although dominant, and either var. denseplicatum no evidence is yet obtained in ammonoids. 685. Phenotypic substitution of Gaudryceras 249 Upon examination of the numerical ratios The fact that the ratio of two forms is of the specimens of Table 1, and no kept constant in two distant areas is significant differences are detected from unfavourable for the supposition of auto­ the hypothesis of a ratio 1: 1 (Table 12). polyploidy. The large size of var. intermedillm It is most appropriate to regard them recalls us of the autopclyploidy but such as a sexual dimorphic pair. a phenomenon is very rare in animals.

Table 12. Chi-square matrix with Yate's correction (2 x 2 contingency table), which indicates the significance for the difference between the numerical ratio of Yare intennedium to yare denseplicatum and idealized ratio on the sexual dimorphism (1 :1). Upper: Naibuchi, lower: Obira. Stage Mh6,8 Mh6a-,B Mh6,,2 Mh6,,1 Mh5 Mh4

Actual ratio 8:9 0: 1 4:1 1 : 0 0:2 3: 1 Result 0.029 0.667 0.250 0.667 0.000 0.000

Stage I amakus. miho. uwajim. teshio. hobets. labiatus Actual ratio 1 : 0 0:0 1 : 6 1 : 3 2:9 0:0 Result I 0.667 0.737 0.000 1. 264 7. 20.05("= 1) = 3.841

Characteristics of yare tenlliliratllm California (MATSUMOTO, 1959b) and South Africa (HOEPEN, 1921) similar ones were Ontogeny: The ontogenetic develop­ reported as d. tenuiliratwn or under a ment of var. tenuiliratllm was explained different name. Cf. tenuiliratu11l, which in detail with the Santonian samples is not available at my hand, is however, (HIRANO, 1975). The sutural pattern of rather rare in California and I omit this this variety is ontogenetically same as species under the assumption that this those of var. denseplicatum and var. inter­ treatment does not influence on the final mediu11l. The growth ratio of the radius results. Thereupon I studied the geo­ length to the spiral is smaller in the graphic variation of the present variety present variety than in the other two in the Japan-Sakhalien area but no partic­ varieties in the later stages. The cross ular trend like cline was detected through section of the costa is quadrate like that the range as exemplified by the Santonian of var. intennedium. The adult size of samples (HIRANO, 1975). the present variety is similar to that of Then I examined for chronological var. denseplicatu11l. In short, as mentioned change of the growth pattern of the by MATSUMOTO (1941) these three varie­ spiral from the amakusensis zone to the ties are different from each other in some japonicus zone (Fig. 10), but detected none. points but at the same time they have Discussion: The morphological differ­ common or similar characters in other ences of var. tenuiliratu11l from var. points. denseplicatu11l and var. inter11ledium are Geographic and chronologic variation: macroscopically and biostatistically clear The distribution of this variety is almost in some characters as mentioned in the restricted to Japan-Sakhalien, but from previous section. The sutural pattern of 250 Hiromichi HIRANO

o o o Sample from amokusensis Zone o o. • ... Sample fr~m j~ponicus Zone. o ..... '" o . . o t . • " o

100

1.0

~ after 91& ~ before 9 7t. I N=4 §; . o.v NB 3 .2..'- I N=8 N=1i - -~ - -I ~~ ... -[]- ) N~l

1'~ I 0 .0800 I .1 00 .1 00 N8~1400 .1600 .1800 0.10 2.0 4.0 6.0 8.0 10.0 12.0 14.0 n Fig. 10. Growth pattern and ratio of the radius length to the spiral of var. tenuili­ r.a-tum from Obira. In the square, the mean value and 95% confidence interval of the growth ratio is .shown. Sample from the naumanlli zone is indicated by a broken line. var. tenuiliratunz, however, is not distin­ medium in these two localities (Table 1). guishable from those of var. denseplicatum That is, these patterns clearly indicate and var. intermediu71l. that var. tenuiliratum replaced the pair The rise and fall of var. tenuiliratum of var. denseplicalum and var. intennedium. are exemplified in two representative Var. tenuiliratum has been regarded a localities, NaibuclTi and Obira (Table 1), single and independent species by most and both two examples show that it authors. Did it speciate from another began to appear in Coniacian and flourish­ species than C. denseplicatu71i (=C; d. ed in Santonian. Next I compare the var. denseplicatum+C. d. var. intermedium) numerical fluctuation of the specimens of or from C. denseplicatu71l in other area var. tenuiliratum with that of the pair of like the model of allopatric speciation, var. denseplicatu71l and var. intermedium migrating to Japan-Sakhalien and flourish­ (Fig. 3). ing there, taking the niche of C. dense­ The chronological change of the num­ plica tum ? The numerical ratios of the erical ratio of the specimens of var. specimens of three varieties (var. tenuili­ tenuiliratum to those of the pair of var. ratum: var. denseplicatum+var. inter­ denseplicatum and var. intermedium shows medium) in these two localities are almost nearly the same pattern in the two local­ equal to each other except in the case of the ities (Table 3, Fig. 3), notwithstanding japonicus zone vs. Mh6a-j3. Why did the the different chronologic patterns of the ratios change in the same pattern in the number of var. denseplicatum+var. inter- two places, the distance 'of which is as 685. Phenotypic substitution of Gaudrycems 251 great as 300 km ? isolated population must have arisen in Here I consider three hypothesis which the marginal part of J apan-Sakhalien. The may explain the relation between "tenuili­ Turonian sediments occur in great thick­ ratum" and the pair of var. denseplicatum ness and lateral extent in this area, and and var. intermedium. The first and fossil preservation is very good. However, second hypotheses assume "tenuiliratum" we have not succeeded in finding the as an independent species from C. dense­ intermediate form of those two "species" plica tum. That is, 1. "C. tenuiliratum" under discussion for the last 100 years speciated from a species other than C. from any locality. If we supposed that denseplicatum, migrating to Japan-Sakha­ "originally such an intermediate form lien area and adapted to an environment existed", here we can apply the model of this area, 2. "G. tenuiliratum" speciated of ELDREDGE and GOULD (1972) (I do not from C. denseplicatum in some marginal intend to deny their model). If the or semi-isolated places and migrated to transformation of morphology from the the main distributional area of C. dense­ couple of var. denseplicatum and var. plica tum (as in the model of ELDREDGE intermedium to var. tenuiliratum is grad­ and GOULD, 1972). In the third hypothesis, ual, the discovery of intermediate indivi­ on the contrary, "tenuiliratum" is the duals would be expected. On the other polymorphic pair (transient polymorphism) hand if "tenuiliratum" arose as a result with the couple of var. denseplicatum and of adaptation for different conditions than var. intermedium. Which would be the denseplicatum, the optimum condition of most reasonable explanation? the former would have been much dif­ Firstly case 1 is considered. The first ferent from that of the latter. However, appearance of "tenuiliratum" is in the the fact that these two "species" coex­ early Coniacian and therefore we must isted for 12 million years after the seek the ancestor in the Turonian species "speciation" denies this necessary condi­ of Caudryceras. The only applicable spe­ tion. cies is C. varagurense which is known in Thereupon I search for a more reason­ the Turonian of India and South Africa. able explanation. That is, we are led to There is not more positive evidence of the thought that "tenuiliratum" is one the speciation of "tenuiliratum" from C. and the same species as denseplicatum. varagurense than the interpretations men­ Although they are one species, the height tioned below although C. varagurense of the subcostae and the whorl growth resembles "tenuiliratum" in appearance. pattem in some stages are different and In case 2 we assume that the speciation there is no intermediate form. Therefore, of "tenuiliratum" from C. denseplicatum they should be regarded as a pair of proceeded in the marginal isolated area dimorphism. In spite of the different of the distribution of C. denseplicatum durations and the different patterns of and "tenuiliratum" migrated to the main local rise and fall in Japan and Sakhalien, area, J apan-Sakhalien. after the complete the relative frequencies of "tenuiliratum" reproductive isolation was established. to the pair of var. denseplicatum and var. According to the model of ELDREDGE intermedium are in the same pattern as and GOULD (1972). this process is likely mentioned in the early part (Table 3, Fig. to have proceeded fairly rapidly. Because 3). This fact seems to suggest transient the distribution of C. denseplicatum of polymorphism. That is, var. tenuiliratum Turonian age is only J apan-Sakhalien, the may constitute dimorphism with the pair 252 Hiromichi HIRANO

of var. denseplicatum and var. intermedi­ The decision whether a single gene can um, and arised by some mutation (gene change the morphology or not depends mutation, chromosome aberration, position on the. condition if the gene is a part of effect of supergene or other case) from the polygenes or the major genes. Ex­ the pair of var. denseplicatum and var. amples of the polymorphism owing to the intermedium earlier than the early Conia­ mutation of a single major gene are cian, and survived until the middle or commonly known. early Campanian after the decline of the Further, the rate of mutation is known pair of var. denseplicatum and var. inter­ as low as 10-5 to 10-6/1 gene locus medium. As the actual mode of the (DOBZHANSKY, 1951). In population genet­ adaptive strategy of organisms this ex­ ics the cases that the mutation recurrents planation may be more reasonable. at a constant ratio p. in each generation Furthermore, the fact that var. tenuili­ [xt=xoe-1tt , t: generation, Xo: frequency ratum is rarely but actually obtained of Al at the starting generation] and that from the Turonian is reasonably explained the back mutation arises [Xt= p.~v + only in this case. (1-p.-v)t(xo- p.~v)' v: rate of muta­ Additional consideration on tion from A2 to AI] (KIMURA, 1960; transient polymorphism HAYAMI, 1972, 73a, b) are considered. Here Studies on transient polymorphism of I discuss the change of the gene frequen­ living organisms are not as numerous cy on the assumption that the change is (e. g., KETTLEWELL, 1955, 56; KOMAl et caused not by recurrent mutation but by aI., 1950; KOMAI, 1956) in comparison with natural selection as has commonly been those on balanced polymorphism (e. g., suppossed by evolutionists. KOMAl and EMURA, 1955; CAIN and SHEP­ Case of recessive mutant gene: Assum­ PARD, 1954; SMITH, 1973; on many spedes ing that var. tenuiliratum represents the of butterflies and many species of Dro­ recessive homozygote, I calculate the rela­ sophila by many geneticists). This is tive gene frequencies during the duration merely because long period is required from the number of specimens (Tables for a study of transient polymorphism. 13, 14, Figs. 3, 11). The life span of the Transient polymorphism is the poly­ species is assumed as ten years or so morphism existing during the period when based on the rate of shell secretion cal­ an allele is being replaced by a superior culated from the isotopic study on am­ one (MA YR, 1970). monites by STAHL and JORDAN (1969), As the polymorphism mentioned here the origin of constriction of the molluscan is represented by two phenotypes (var. shell studied by UNO (1962) and the tenuiliratum and the sexual couple of var. ontogenetic pattern of constriction of var. denseplicatum), we can consider that a tenuiliratum (HIRANO, 1975). The strati­ pair of allele has the relation of dominant graphie range of var. tenuiliratu7n is from and recessive. I consider both cases of the Coniacian uwajimensis zone to the dominant mutation and of recessive muta­ Santonian amakusensis zone in Obira and tion, since the gene produced by mutation is 9 m. y. in absolute age (HARLAND et is usually recessive but disadvantageous ai. ed., 1964). In Naibuchi it is from the (I avoid discussing the problems of neutral uwajimensis zone to the Santonian japo­ theory here). nicus zone and is 12 m. y. (Table 1). 685. Phenotypic substitntion of Gaudryceras 253

Table 13. The change of the gene frequency from MM to Mh6.8 observed in Naibuchi samples. The case of dominant and that of recessin: are both calculated. p is the frequency of the wild type gene. Phenotype Wild type Case of dominant Case of recessive Age Horizon m.y. d All p q p q -76 Mh6;3 36 100 0.265 0.515 0.485 0.143 0.857 Santonian Mha-,8 17 11 0.607 0.779 0.221 0.373 0.627 Mh6a2 19 34 0.358 0.598 0.402 0.199 0.801 Mh6a1 9 0.900 0.949 0.051 0.684 0.316 82 Mh5 -I 0 1. 000 1. 000 0.000 1. 000 0.000 Coniacian Mh4 7 1 0.875 0.935 0.065 0.646 0.354 88 Mh3 0 1. 000 1. 000 0.000 1. 000 0.000 Turonian Mh2 0 1. 000 1. 000 0.000 1. 000 0.000 Mhl 1. 000 1. 000 0.000 1. 000 0.000 94

Table 14. The change of the gene frequency from Turonian to Santonian obserYed in Obira samples. The case of dominant and that of recessive are both calculated. p is the frequency of the wild type gene. Phenotype Wild type Case of dominant Case of recessive Age Zone m.y. d All p q p q -76 japonicus 0 19 0.000 0.000 1. 000 0.000 1. 000 Santonian amakusensis 22 19 0.537 O. 733 0.267 0.319 0.681 82 mihoensis 40 3 0.930 0.964 0.036 0.736 0.264 Coniacian uwajimensis 10 1 0.909 0.953 0.0-15 0.699 0.301 88 teshioensis 35 0 1. 000 1. 000 0.000 1. 000 0.000 Turonian hobetsensis 60 0 1. 000 1. 000 0.000 1. 000 0.000 labiatus 5 0 1. 000 1. 000 0.000 1. 000 0.000 94

Because the relative frequency of speci­ available. If A2 be recessive, the wild mens is the average value in each zone, type composed of AlAl or AlA2. and the the absolute age of the middle part of mutant type A"A 2 would be observed. each zone should be employed for the This means that the relative frequency following calculation. The number of of the mutant gene q of the mutant type the generation follows that 6.105 in the AzAz is calculated as the root of the ratio former and 9.105 in the latter. Here, the of the mutant type specimens. relative frequency of the dominant gene is Here I introduce the coefficient of selec­ p, and that of the recessive gene is q tion, s (if the recessive individuals fitted (Tables 13, 14). When the wild type gene better than the dominant individuals to is Al and the mutant gene is A z, three the natural selection, s is negative) and genotypes, AlAl' AlA2 and A2Az are the following formula of the change of 254 Hiromichi HIRANO _ sx(1-x)2 above results. the gene frequency, Llx-1- s(1-x)2' x: Before going further I propose some gene frequency, is obtained. When s is values with regard to the fixation of much smaller than 1, we can substitute mutant genes. As the small s worked the above formula by the following equa- effectively, the effective population size tlOn,. c[i-sxdx _ (1 -x)2 . (Ne) of the species is assumed to exceed In my study the absolute value of s is 10 6 • The probability of fixation (U) is 2s also assumed to be much smaller than 1. in the case of the complete dominance To solve the above formula, we can apply and U = v2s/(rrN) in the case of the com­ plete recessive. the transformation z=log.(l":J+(l~x) The generation at which the relative (KIMURA, 1960). Then, ~~ =sx(1-x)2 frequency of the mutant attains 0.5 is calculated below. dz becomes Tt= s and the value of z at 1. Case of recessive the t generation is given in the formula, Obira t=6.3·105 Zt=st+zo• Here Zo is the value of z at Naibuchi t=3.2·105 the initial generation and t is the gener­ 2. Case of dominant ation. The generation has already esti­ Obira t=1.0·105 mated and now I can obtain the value of Naibuchi t=9.2·105 s. That is, in Obira s=-3.5·1O- 6 and in That is, the relative frequency of the Naibuchi s=-4.5·1O- 6• The values are mutant gene attained 0.5 after about 1/10 reasonably small as we can assume. from total generations passed in Obira (1/14 the fact that these two types replaced in recessive case and 1/9 in dominant through 9 m. y. or 12 m. y., and the values case) and about 1/13 total generations are one figure smaller than that of Crypto­ (in dominant case) or 1/38 (in recessive pecten vesiculosus (HA YAMI, 1973b). case) passed in Naibuchi. Case of dominant mutant gene: Like­ In either case, dominant or recessive. wise the following values are obtained in the analyzed results indicate that the Obira and Naibuchi, and the values of s wild type of C. denseplicatum did not 6 are the figures of 10- in the two places. become extinct as it might appear but Obira s=3.9·10- 6 the wild type was gradually replaced by Naibuchi s=3.9·10- 6 the mutant type, caused by the difference Discussion: As mentioned in the early of fitness for selection in the order of part of this chapter, there are no data 10- 6• which are directly comparable with the Furthermore, the mutant type of C.

Explanation of Plate 33 All figures x 0.8

1. C. denseplicatum var. denseplicatum. I.471, from the Miho River, Naibuchi. Horizon: Mh3 Collected by M. KAWADA, a: ventral view, b: lateral view. 2. C. denseplicatum var. tenuiliratum. I-4034, from the Second stream of the eighteenth fore­ stry district, Naibuchi. Horizon: Mhl·3. Collected by M. KAW ADA, a: ventral view, b: . lateral view. 3. C. denseplicatum var. intermedium. I-185, from Makaushuppe, a branch of the Sanushibe River, Hobets. Horizon: uncertain. Collected by Y ABE, H. HIRANO: Gaudryceras Plate 33

Ib 685. Phenotypic substitution of Gaudryceras 255

Zone Slbdivision Age of in Dominant mutant gene Recessive mutant gene Inoceramus Naibuchi C Mh6B ...... -. .... 0 japonicus ~ t---€J ----... I I C Mh60CB • III MhSoc? .....---. III amakusensis ~ o----e--- Mhfioc1 •• I I. • I • I ...... U mihoensis Mh5 III oe-< ~ c 0 uwajimensis Mh4 I. I I • I U 10 I I 8 I teshioensis Mh3 • • c 0 0 .-III • Naibuchi c hobetsensis Mh2 • • 0 Obira 0.... 0 0 :l t- labiatus Mhl • • 0 0 o 02 0.4 0.6 0.8 1.0 0 0.2 0.4 0.6 0.8 1.0 Fig. 11. Historical change of the mutant gene frequency. 95% confidence interval is shown by a bar. denseplicatum disappears in the middle or Sakhalien, the same geographic and the early Campanian and C. striatum appears stratigraphic distribution. They are here about the time. In the detailed biostrati­ degraded to C. denseplicatum var. dense­ graphic studies (MATSUMOTO, 1943, 59a; plica tum and C. d. var. intermedium, KANIE, 1966) C. striatum is said to over­ respectively. lap in time with the mutant type of C. The ratio of the frequencies of another denseplicatum. The morphological resem­ nominal species, C. tenuiliratum, to var. blance between these two species has denseplicatum and var. intermedium shows already been mentioned by MATSUMOTO the same pattern through the duration in (1941). Transient polymorphism may have the two areas, Obira and Naibuchi, also occurred in this case. If this assump­ notwithstanding that the chronological tion is true, the extinction of C. dense­ changes of the frequencies of the pair of plica tum in the middle or early Campanian var. denseplicatum and var. intermedilll1l also is not caused by a drastic change of are in different patterns between these the physical environment or similar kinds two areas. In addition to this fact, in of other change. virtue of the consideration of the mor­ phometric analyses, the geographic and Conclusion the stratigraphic distribution, this nominal species actually seems to belong to the The two nominal species, C. densepli­ same species, C. denseplicatul1l, and catum and C. intermedium, are explained transient dimorphism is the most reason­ as a sexual dimorphic pair on the basis able relation. Here C. tenlliliratul1l is of morphometrical distinction found only degraded to C. denseplicatu17l var. tenuili­ in the adult shell, insignificant chrono­ ratul1l. logical change of the numerical ratio of The change of the relative gene fre­ the specimens, commonly observed rela­ quency is obtained for the cases of the tion of coexistence in Hokkaido and dominant mutant gene and the recessive 256 Hiromichi HIRANO mutant gene on the supposition that the car, p. 1-106, pIs. 1-11. change is not caused by recurrent muta­ DOBZHAl'SKY, T. (1951): Genetics and the origin of species. 3rd., Columbia Univ. tion but by natural selection, and the Press, N. Y., 361 p. coefficient of selection is obtained as the DOWDESWELL, W. H. (1970): The mechanism 6 figures of 10- • Var. denseplicatum and of evolution. Heinemann Educ. Book Ltd., var. intermedium may have seemingly Japanese ed., by Kawadeshoho Co., Tokyo, become extinct, but they actually survived 173p. till the end of Santonian or the early ELDREDGE, N. and GOULD, S. J. (1972): Pun­ Campanian. They were, however, grad­ ctuated equilibria An alternatiye to phy­ ually replaced by the individuals of letic gradualism. In SCHOPF, T. J. ed. another phenotype (dimorphic pair) which (1972) : Models in paleobiology, p. 82-115 probably had higher fitness. This seems in 250p., Freeman, Cooper & Co., San to be significant in the evolutionary Francisco. studies not only of ammonoids but also GOULD, S. J, (1966): Allometry and size in ontogeny and phylogeny. Bio!. Rev., vol. many other taxa. 41, p. 587-640. Speciation is a function of population HARLAND, W. B. et al. (196'1): The phanero­ size, the degree of initial variation of the zoic time-scale. Vol. 120s supplement to gene pool in the peripheral isolate and Q. J. G. S. London, 458p. the degree of fitness of the peripheral H.<\ YA;"II, I. (1972) : Possibility of " paleogenet­ isolate. Therefore there can be several ics". Jour. Geol. Soc. Japan, vol. 78, no. models on evolution. Some cases may 9, p. 495-506. fit phyletic gradualism and others may -- (1973a): An evolutionary interpretation fit punctuated equilibria. The present of biostratigraphic zones. Ibid., vol. 79, no. 3, p. 219-235. case is an example of the evolutionary -- (1973b) : Discontinuous variation in an mode by the transient polymorphism, and evolutionary species, Cryptopecten vesi· it follows that the model proposed by culosus, from Japan. Jour. Pa!aeont., vol. HAYAMI (in HAYAMI and OZAWA, 1975) 47, no. 3, p. 401-420, pIs. 1-2. is supported as one of the major models -- and OZAWA, T. (1975): Evolutionary of evolution not only by genetical theory models of lineage-zones. Lethaia, vol. 8, but also by palaeontological evidence. p. 1-14. HIRANO, H. (1975) : Ontogenetic study of late References Cretaceous Gaudryceras tenuiliratum. M em. Fac. Sci., Kyushu Univ., Sa. D, Geo!., CAIN, A. J, and SHEPPARD, P. M. (1954) : Nat­ vol. 22, no. 22, no. 2, p. 165-192, pIs. 24-26. ural selection in Cepaea. Genetics, vol. 39, --, MATSUMOTO, T. and TAl'ABE, K. (1977) : p. 89-116. Mid-Cretaceous stratigraphy of the Oyu­ COLLIGNON, M. (1956): An'lmonites Neocre­ bari area, central Hokkaido. IGCP-MCE tacees du Menabe (Madagascar), IV, V Report. In MATSUMOTO (ed.), Palaeont. and VI. Ann. Geol. Servo Min., Madagas- Soc. Japan, spec. vol. 21, p. 1-10.

Explanation of Plate 34 All figures x 0.8 1. G. denseplicatum val'. denseplicatum (a fully grown up specimen). R2113-1, from the Obira­ shibe Riber, Obira •. Horizon: I. hobetsensis zone. Collected by HIRANO and TANABE. 2. G. denseplicatum val'. intermedium. Ventral view of the PI. 33, Fig. 3. Hate 34

HI RANG : Gaudryceras 685. Phenotypic substitution of Gaudrycems 257

HOEPEN, V. (1921): Cretaceous Cephalopoda stratigraphy of Japan Part 1. Mem. Fac. from Pond oland. Ann. Transvaal Mus., Sci., Kyushu Univ., Ser. D, Ceo!., vol. 1, vol. 8, no. 1, p. 7, pI. 2. p. 129-280, pis. 5-20. HOWARTH, M. K. (1965): Cretaceous ammo. -- (1943): Ditto, Parts II & III, Ibid., vol. nites and nautiloids from Angola. Bull. 2, p. 97-237. Brit. Mus. (Nat. Hist.) , Ceol., vol. 10, p. -- (195-1): Selected Cretaceous leading am· 335-412, pIs. 1-13. monites in Hokkaido and Saghalin. In HUXLEY, J. (1932) : Problems of relative growth. MATSU\IOTO ed. (195-1): The Cretaceous 1972 ed. by Dover Co., N. Y., 312p. system in the japanese Islands. p. 243-313 JIMBO, K. (1894): Beitrage zur Kenntnis der in 32:lp., pis. 17-36 in 36 pis. japan Soc. Fauna der Kreideformation von Hokkaido. Prom. Sci. Palaeont. Abhandl., 6(N. F. Bd. 2), -- (1959a): Zonation of the upper Creta· p. 149-194, pIs. 17-25. ceous in Japan. lvIem. Fac. Sci., Kyushu KA,\"IE, Y. (1966): The Cretaceous deposits Univ., Ser. D, Ceol., vol. 9, no. 2, p. 55- in the Urakawa district, Hokkaido. jour. 93, pis. 6-1l. Ceol. Soc. japan, vol. 72, no. 7, p. 315-328. -- (1959b): Upper Cretaceous ammonites of KETTLE\\"ELL, H. B. D. (1955): Selection ex· California Part II, Ibid., Special vol. 1, p. periments on industrial melanism in the 1-172, pIs. 1-41. Lepidoptera. Heredity, no. 9, p. 323-342. -- and OKADA, H. (1973): Saku Formation -- (1956): Further selection experiments of the Yezo Geosyncline. Sci. Repts., on industrial melanism in the Lepidoptera. Dept. Ceol., Kyushu Univ., vol. 11, no. 2, Ibid., no. 10, p. 287-30l. p. 275-309. KIyIURA, M. (1960): Introduction to popula. --, --, HIRANO, H. and TANABE, K. (1977) : tion genetics. Baifukan Co., Tokyo, 312p. Mid·Cretaceous biostratigraphic succession KOyIAI, T. (1956): Genetics of ladybeetles. in Hokkaido. Ann. Mus. d'Nist. Nat. Nice Advances in Cenetics. no. 8, p. 155-188, (in press). Academic Press, N. Y. MAYR, E. (1970): Populations, species, and --, CHINO, M. and HOSHINO, Y. (1950) : Con. evolution. Belknap Press of Harvard Univ.,. tribution to the evolutionary genetics of Cambridge, 453p. \ the ladybeetle Harmonia. Cenetics, vol. 35, NO\IURA, E. (1926): An application of a == kbx p. 589-60l. in expressing the growth relation in the -- and E\IURA, S. (1955) : A study of popu· freshwater bivalve, Sphaerium heterodon lation genetics on the polymorphic land PILS. Sci. Repts. TollOku Imp. Univ., 4th snail Bradybaena similaris. Evolution, vol. ser. (Bioi.), vol. 2, p. 57-62. 9, p. 400-418. OBATA, 1. (1959): Croissance relative sur KOSSMAT, F. (1895): Untersuchungen liber quelques Espe'ces des Desmoceratidae. die Sudindische Kreideformation. Beitr. Mem. Fac. Sci., Kyushu Univ., Ser. D, Palaeont. Ceol. Ost .. Ung., vol. 9, p. 97- Ceol., vol. 9, no. 1, p. 33-45, pIs. 4-5. 203, pis. 15-25. -- (1960): Spirale de quelques ammonites. KGLLYiANN, J. and WIED\!ANN, ]. (1970): Ibid., vol. 9, no. 3, p. 151-163, pI. 15. Significance of suture in phylogeny of am· -- (1961): Analyses of growth in palaeon. monoidea. Univ. Kansas Paleont. Contr. tology with special reference to ammoni· Paper 47, p. 1-32. tes. Earth Science, no. 55, p. 23-28. MATSUMOTO, T. (1941): A study on the reo -- (1965) : Allometry of Reesidites minim us, lation among the different species, with a Cretaceous ammonite species. Trans. special reference to the duration of a fos· Proc. Palaeont. Soc. japan, N. S., no. 58, sil species. jour. Ceol. Soc. japan, vol. 48, p. 39-63, pIs. 4-5. no. 568, p. 17-37 (In Japanese with English OSIIl\IA, C. et al. ed. (1974): Adaptation and abstract) evolution of population. Modern genetics -- (1942): Fundamentals in the Cretaceous series no. 5, Asakura book Co., Tokyo; 258 Hiro?nichi HIRANO

270p. vincta (MONTAGU) in northeast England. PALFRA:,IAN, D. F. B. (1966): Variation and Jour. mar. bioi. Ass. U. K., vol. 53, p. 493- ontogeny of some Oxfordian ammonites: 520. Taramelliceras richei (de LORIOL) and STAHL, W. and JORDAN, R. (1969): General Creniceras renggeri (OPPEL) from Wood­ consideration on isotopic palaeotempera­ ham, Buckinghamshire. Palaeontology, vol. ture determinations and analyses on Juras­ 9, pt. 2, p. 290-311, pIs. 48-52. sic ammonites. Earth & Planet. Sci. lett., -- (1967): Variation and ontogeny of some 6, p. 173-178. Oxfordian ammonites: Distichoceras bico­ TANABE, K., HIRAl'O, H., MATSUMOTO, T. statum (STAHL) and Horioceras baugieri and MIYATA, Y. (1977): Stratigraphy of (D'ORBIGNY), from England. Ibid., vol. the upper Cretaceous deposits in the Obira 10, pt. 1, p. 60-94, pIs. 9-13. area, northwestern Hokkaido. Sci. Repts. -- (1969): Taxonomy of sexual dimorphism Kyushu Univ., Ceol., vol., 12, no. 3, p. in ammonites: Morophgenetic evidence in 181-202. Hecticoceras brightii (PRATT). I. U. c. S. THOMPSON, D. (1917): On growth and form. Ser. A, no. 1, p. 126-154, pIs. 6-8. Cambridge Univ. Press, Japanese ed. by SCI-lINDEWOLF, O. H. (1954) : On development, Univ. Tokyo Press, 1973, Tokyo, 215p. evolution and terminology of ammonoid U:--;o, Y. (1962): Studies on the aquiculture suture line. Mus. Compo Zool. Bull., Har­ of Turbo cornutus SOLANDER with special vard Univ., vol. 112, p. 217-237. reference to the ecology and periodicity SHIMIZC, S. (1935): The upper Cretaceous of the growth. Jour. Tokyo Univ. Fish., cephalopods of Japan. Part 1. Jour. Shang­ SPecial ed., vol. 6, no. 2, p. 1-76. hai Sci. Inst., sec. 2, vol. 1, p. 159-226. Y ABE, H. (1903): Cretaceous Cephalopoda SIMPSON, G. G. (1961): Principles of animal from Hokkaido Part 1. Jour. Coli. Sci., taxonomy. Columbia Univ. Press, N. Y., Imp. Univ. Tokyo, vol. 18, art. 2, p. 1-55, Japanese ed. by Iwanami book Co., Tokyo, pIs. 1-7. 272p. YA:\IAMOTO, M. ed. (1973): Marine ecology. SMITH, D. A. S. (1973): The population biology Oceanography series, 9, Univ. Tokyo Press, of Lacuna paliidula(DA COSTA) and Lacuna Tokyo, 213p.

1&Jt!JS.!IE;f.e7 ,/-'I:::t"1" Caudryceras Q)*!JUl'!.iiltJ!: B*t-;J:V:~:t: J: 1)f.4 Ght.::. C. denseplicalum, C. intermediullZ, C. lenuiliratum Q)1(*f~")\"-C, lllf*Je1:~AQ)1:4P.JiJ!IJ 'iE, :itl!JffiB'~· ~rfl¥J)j-;{ff, {ltiI{$:~.Lt~Q)t9tW~LJ.::.c::: 0, t'l* (1941) l~ti'i:fjl,j~hl'f,f:mCtJ: "? -C \,'t.::.J:ilt:;::::~Q)I*H~d)~(1zQ)~I~ID?fJJl-C ~ ::5::: c iJ~'FIJ"? t.::.o -ttd?'!?, C. denseplicatum c C. inlermedium ft, :::h"j:-CI~~ilGh-C\"::5M~Je1:J:Q)%fL.H\&fj;J,Q){t!!K., ~&Q). ~, )j-;{ff:itl!J1iX&O:Jf.'ff1;:Q)-It ~1~~ff~Jt!JrI31~iili c -C Q)-'iEQ)lIl{$:~JtQ)*lM'l.J\ GM;I¥J=mi. c 'J'1J1f)f ~ h::5 C. tenuiliratullZ it::: Q) jiIij~I~;ll

:t:P'J~h~-c, J:ilt:;=mi. c Q){IIiI{$:~JtQ)I!t~~*Oi)::5 c jj'iJ C/~!J '/~~-t 0 ::: h G Q)FI3'Q)~i*~ID? 1j)'j-t::5 t.::.ool-=', ::::")Q){&ID?~t~ -Ct9tWL. t.::.~*, C. tenuiliralum ftlliIilt:;=mi.c jj'iJ-;fi-C}/&lil!: l¥J~mi.cL.-CID?fJJl-t::5Q)~.t~Jffil¥Jcmhhko~:::-C~~Q).~.~~I¥J~*~M~*. 9E1:I~")\"-C~~L.t.::.o f!l!:f 5L. ~

Explanation of Plate 35

1. C. denseplicalum var. inlermediullZ. N191-p, from the Santan River, Naibuchi. Horizon: Mh6a. Collected by T. MATSUMOTO X 0.8 HIRANO: Gaudryceras Plate 35 Trans. Proc. Palaeont. Soc. Japan, N. S., No. 109, pp. 259-279, pIs. 36-38, April 30, 1978

686. ADDITION TO THE MESOZOIC PLANTS FROM THE AKAIW A FORMATION (UPPER NEOCOMIAN), THE ITOSHIRO GROUP, CENTRAL HONSHU, INNER ZONE OF JAPAN*

T ATSUAKI KIMURA

Tokyo Gakugei University, Koganei, Tokyo 18,1

and

SINJI SEKIDO

Komatsu Senior High School, Komatsu 923

Abstract. This paper deals with the additional palaeobotanical descriptions of newly discriminated species to the Akaiwa flora formerly described by us (1976) in the present transactions. The newly described species are as follows; Gleichenites nipponensis, Coniopteris saportana, Adiantopteris sewardii, A. toyoraensis, Raphaelia diamensis, Dictyozamites efr. obliquus, Nilssonia schmidtii, Butefia? sp., Ginkgoites paradianloides, Arclobaiera? sp., Elalocladus sp. C, E. sp. D, Protodammara sp. and Carpolithes sp. In addition, both Gleicheniles porsildii and Cladophlebis ex gr. wi!· liamsonii are redescribed with some emendation and additional remarks respectively. It might be notable that Raphaelia diamensis, which has so far been regarded as a Jurassic species, is now found from the Japanese Lower Cretaceous. The occurrence of Coniopteris saportana, Dictyozamites efr. obliquus, Nilssonia schmidtii, Ginkgoiles paradiantoides and Protodammara sp., is the first record in Japan. After all, the Akaiwa flora is now consisting of 26 genera and ;:;3 species. As formerly mentioned by us, both the Akaiwa flora (late Neocomian) and the underly. ing Oguchi flora (early Neocomian, the main part of the "Tetori flora") in the Inner Zone of Japan, are similar in composition to the coeval floras in V AKHRA~IEEV'S Siberian Palaeofloristic Area, but are not so to those in the Outer Zone of Japan.

Introductory Afterwards we collected many more specimens from the Bettokuzure point, of Last year we described the Akaiwa the upper layers of the Akaiwa Forma­ Flora with its comparison with the coeval tion, the Itoshiro Group, the Tetori (or floras in the Outer Zone of Japan and in Tedori) Supergroup, and found additional the Siberian Palaeofloristic Area formerly fifteen new forms among them. proposed by VAKHRA~IEEV, and men­ The present work deals with the des­ tioned its significance in the Mesozoic cription of these new forms, most of floral change in Japan and her adjacent which are common to the Late Jurassic areas (KIMURA & SEKIDO, 1976b). to the Early Cretaceous floras in the * Received July 20, 1977; read Jan. 21, 1977 V AKHRAMEEV'S Siberian Palaeofioristic at the annual meeting of the society, Tokyo. Area. 259 260 Tatsnaki KIMURA and Sin}i SEKIDO

Table 1. Composition and localities of the Akaiwa Flora (KIMURA & SEKIDO, 1977)

Localities BK OS T OG SI OZ Genera & species -- ~ 1------Equisetites spp. (stem and tubers) 0 0 0 0 ------Cleichenites nipponensis OISHI* 0 0 C. porsildii SEW ARD** 0 0 Coniopteris burejensis (ZALESSKY) SEWARD 0 0 •0 C. saportana (BEER) V ACHRAMEE\'* 0 0 C. sp. cfr. C. hymenophylloides (BRONGNIART) SE\\"ARD 0 Birisia onychioides (VASSILEVSKAJA & KARA-MuRSA) 0 •0 •0 SA'dYLINA Asplenium cfr. dicksonianum BEER 0 Adiantopteris sewardii (YABE) VASSILEVSKAJA * 0 0 •0 A. toyoraensis (O!SHI) VASSILEVSKAJA* 0 0 0 A. spp. (A, B, C) 0 0 0 0 • ------• -- Onychiopsis elongata (GEYLER) YOKOYAMA 0 0 0 0 0 0 Sphenopteris ex gr. goepperti DUl\KER 0 0 0 S. kochibeana (YOKOYAMA) OISHI 0 0 Cladophlebis ex gr. denticulata (BROl\Gl\IART) 0 0 • NATHORST • • C. (Osmundopsis) distans (BEER) KIMURA & SEKIDO 0 0 (MS) 0 C. ex gr. williamsonii (BRONGNIART) BROl\GNIART* 0 0 0 C. spp. 0 0 Raphaelia diamel1sis SE\\,ARD* 0 0 0 R. spp. (A, B) 0 ------• -- Dictyozamites cfr. cordatus (KRYSHTOFOVICH) PRYNADA 0 D. cfr. obliquus SAMYLINA* 0 • Nilssonia kotoi (YOKOYAMA) OISHI 0 0 • N. lobatidentata V ASSILEVSKAJA 0 0 •0 N. nipponensis YOKOYAMA 0 0 0 N. cfr. orientalis BEER 0 N. schmidtii (BEER) SEWARD* 0 • • • Tetoria endoi KIMURA & SEKIDO 0 0 • Butefia? sp.* 0 ------• -- Cinkgoites digitata (BRONGNIART) SEWARD 0 0 0 C. huttonii (STERNBERG) BLACK 0 0 0 C. paradiantoides (SAMYLIl\A) KI~ICRA & SEKIDO* 0 0 C. sibirica (BEER) SEWARD 0 0 0 Cinkgoidium nathorstii YOKOYAMA 0 0 Pseudotorellia sp. • 0 0 0 • 686. Mesozoic plants from the Alcaiwa Formation 261

CzekaiZowskia sp. 0 Arctobaiera? sp. * 0 • • Leptostrobus sp. 0 • ------• Podozamites angusti/olius (EICHIVALD) HEER 0 0 P. ex gr. lanceolatus (LIKDLEY & HUTTOI\') ERAV\ 0 0 0 P. reinii GEYLER 0 0 0 0 Elatocladus spp. (A, E, C*, D*) 0 . PityophyllulI! lindstroemi NATHORST 0 •0 • Protodammara sp. * 0 • Xenoxylon latiporosum (CRAMER) GOTHAI\' (MS) 0 0 0 0 ------Carpolithes sp. * (Ginkgoites seeds?) 0 Seeds 0 • Problematica 0 0 *; Additional forms here described to our previous work (KIMURA & SEKIDO, 1976b, p. 346, tab. 2). ** ; Additional description and illustration to our previous work. BK; Bettokuzure, southwestern slope of Mt. Hakusan (2,702 m), 5hiramine.mura, Ishikawa.gun, Ishikawa Prefecture. OS; Osugidani, Irahara, 5hiramine.mura, Ishikawa·gun, Ishikawa Prefecture. T; Tamodani, Hambara, Izumi.mura, Ono.gun, Fukui Prefecture. OG; Common or allied forms to the underlying Oguchi Flora (Early early Cretaceous in age). 51; Common or allied forms to the floras ranging from the Late Jurassic to the Early Cre­ taceous in age in V AKHRA~IEEV'S Siberian Palaeofloristic Area. OZ; Common or allied forms to the coeval floras with the Akaiwa Flora in the Outer Zone of Japan. (open circles and solid ones showing common and allied forms respectively).

Table 1 shows the composition and help in collecting fossil plants. We also localities of the Akaiwa Flora newly give our thanks to Miss Tamiko OHANA, edited by us, among which the species a graduate student of the Tokyo Gakugei with an asterisk and two asterisks are University for her kind help in drawing described in this paper. the figures in this paper. This study has been undertaken with the aid from the Section of Cultural Acknow ledgements Properties Protection, Board of Edu­ We first express our sincere gratitude cation, Ishikawa Prefecture. to Dr. Thomas M. HARRIS, F. R. S., Pro­ fessor Emeritus of the University of Systematic description Reading, England for his very helpful suggestions and kindest reading over the Filicales present manuscript. Family Gleicheniaceae We are indebted to Mr. Keiju YAMA­ ZAKI, a member of the Komatsu City Genus Gleichenites SEWARD, 1910: 351 Museum and many students of the Tokyo Gakugei University for their invariable Gleichenites nipponensis OISHI 262 Tatsuaki KIMURA and Sinji SEKIDO

PI. 37, figs. 4, 5; PI. 38, figs. 3, 4; The present species resembles Gleiche­ Text.fig. 1 nites vegagrandis HERBST (HERBST, 1962a, p. 145, figs. 11, 14-15) and G. san-martini Gleichenites nipponensis OISHI; OISHI, 1940, p. HALLE (Ditto, p. 142, figs. 1-5, 12-13, 16) 202, pI. 3, figs. 2, 3, 3a (Kaisekiyama, the from the Lower Cretaceous (?) Baquero Ryoseki formation; Kuwashima, the Ogu­ formation, Patagonia and also G. juliensis chi formation) ; KIMURA, 1958, p. 13, pI. 1, HERBST (HERBST, 1962b, p. 188, pi. 1, figs. figs. 2, 3; pI. 3, fig. 4; pI. 4; fig. 5; text­ figs. 1, 2 (Mochiana, the Upper Jurassic 1-5; text-figs. 1, 2) from the Middle Juras­ Kuzuryu group). sic of Patagonia. But Gleichenites nip­ ponensis differs from the above three in Description:-Ultimate (the last) pinnae its venation and fewer of sori on a mostly long and narrow, nearly parallel­ pinnule. sided, 4 mm wide, straight and attached KRASSILOV regarded G. nipponensis as at interval of 7 mm to the axis at a wide the fertile frond of his cyatheaceous angle. Pinnules set closely, small, semi­ Alsophilites nipponensis (KRASSILOV, 1967, circular with broadly rounded apex, typi­ p. 113-117). But the Japanese specimens cally 1.3 mm long and 1.2 mm wide, upper clearly have Gleichenia-like sori. surface strongly convex, and attached by Occurrence:-Rare. the whole base perpendicularly to the SPecimens:-BK6-0l0 (A-F). pinna axis; midnerve indistinct, forking at its tip, sending off a pair of lateral, Gleichenites porsildii SEWARD forked once. Sori circular, 0.5 mm in diameter, consisting of five sporangia PI. 37, fig. 3; Text-fig. 2 with a prominent central placenta. Sori occurring on each side of midnerve, but Gleichenites aff. porsildii Seward; KIMURA, often restricted to one on the acroscopic 1975, p. 70, pI. 7, figs. 1-3; pI. 8, fig. 2; side. (The details of sporangia not known). text-fig. 4-4a, b (Uppermost member of the Tamodani formation); KIMURA & Several fragments of penultimate pinnae SEKIDO, 1976b, p. 351, pI. 36, fig. 2; text­ were newly obtained. Pi. 37, fig. 5 shows fig. 2 (Bettokuzure and Osugidani, the possibly an apical portion of a penUlti­ Akaiwa formation). mate pinna in which ultimate pinnae are reduced in length, their apical halves are Description:-Proximal portion of a not segmented into pinnules but only frond with three incompletely preserved shallowly lobed and ending with acutely pinnae. Pinnules fertile, long and narrow, pointed apex. Text-fig. 1 (a-d) shows nearly parallel-sided, ending with rounded outline of sterile pinnae (la) and fertile apex, typically 0.8 cm long and 1.2 mm ones (lb) and position of sorus (lc-d). wide at the middle portion, and the upper Remarks:-The present specimens agree surface strongly convex; margins lobed well with the original ones described by except near apex, a basal pair of lobes OISHI from Kuwashima (or Kuwajima) of expanded. Midnerve of pinnule distinct, the Oguchi formation and also with those persisting to the tip, sending off once or by KIMURA from Mochiana of the Kuzu­ sometimes twice forking secondaries, the ryu group. number of secondaries corresponding to In the present material the sori each that of lobes. Sporangia all shed leaving, composed of five sporangia are seen the depression and the trace of a central clearly but their cells were not visible. placenta on the centre of each lobe, but 686. Mesozoic plants j?·om the Akaiwa Formation 263

~ ~d 1c ~ 1b I ItrY o O.25cm ~ ~·1a o O_5cm

o O_25 cm

- ~5cm I

2c

o o

Text-figs. 1-2: 1 (a-d) ; Gleichenites nipponensis OISHI. la; sterile pinnae (BK6-010A). lb; fertile pinnae, showing venation and position of placentae (small solid circleS) (BK6- 010B). 1c-d; showing sori reconstructed from their depressions, enlarged partly from lb. 2 (a-d) ; Gleichenites porsildii SEWARD. 2a; sterile pinnae (BK6-063) _ 2b; sho\\-ing detailed venation enlarged partly from 2a, each secondary nerve is forking once, then an apical branch forking again, but a proximal one does not so in general. 2c; fertile pinnae (BK6- 028) drawn from PI. 37, fig. 3 (BK6-028). 2d: showing detailed venation and position of sori, and a sorus reconstructed from its depression, in which solid circles show placentae and open circles with dotted line sh-JW the depression of sorus. (Parts drawn by dotted line are imaginary). 264 Tatsuaki KIMURA and Sil1Ji SEKIDO judging from the shape of depression, Coniopteris saportana (HEER) sori circular in form, 0.6 mm in diameter VACHRAMEEV and probably consisting of several spo­ PI. 36, fig. 1; PI. 37, fig. 6; PI. 38, fig. 2; rangia. Text-fig. 3 Sterile pinnules set closely, similar in form to fertile ones, but broader than Dicksonia soportana HEER; HEER, 1876, p. 89, fertile ones and secondary nerves forked pI. 17, figs. 1, 2; pI. 18, figs. 1-3 (Jurasso­ twice. Cretaceous of the Bureja and the Amur). Text-fig. 2 (a-d) shows outline of sterile Dicksonia gracilis HEER; HEER, 1876, p. 92, pI. 17, fig. 3 (JUl'asso-Cretaceous of the pinnae (2a), venation (2b), fertile pinnae Bureja) . seen also in PI. 37, fig. 3 (2c) and details Coniopteris saportana (HEER) V ACHRAMEEV ; of a pinnule together with a restored VAKHRA~IEEV, 1958, p. 79, pI. 4, fig. 4; sorus (2d). pI. 5, fig. 3 (Lo\\"er Cretaceous of the Remarks:-We describe two finer speci­ Lena) ; VAKHRA~IEEV & DOLUDEC-;KO, 1961, mens than those formerly illustrated by p. 56, pI. 4, figs. 3, 4 (Jurasso-Cretaceous us. Judging from its thick rachis, the of the Bureja) ; LEBEDEv, 1965, p. 66, pI. present specimen shown in PI. 37, fig. 3 5, figs. 1-4; pI. 6, fig. 1; pI. 7, figs. 4-5; might represent the proximal portion of text-fig. 15 (Upper Jurassic of the Zeia) ; a frond. Similar specimens, though repre­ SAMYLl:-.iA, 1964b, p. 61, pI. 10, figs. 3, 4a senting the apical portions of fronds, to (Lower Cretaceous of the Zyrianka Coal­ Field) ; 1976, p. 29, pI. 7, figs. 3-6 (Lower present one were already described by Cretaceous of Omusukchan Coal-Field); us. The present and our former speci­ VASSILEVSKAJA, 1966, p. 52, pI. 1, fig. 3 mens are referable to those originally (Lower Cretaceous of the Lena). described by SEWARD (1926, p. 76, pI. 6, figs. 18-19, 24, 30) from the Cretaceous Description :-Frond at least bipinnate. of Greenland, that by SEWARD & CONWAY Rachis comparatively thick, 2 mm across (1935, p. 5, pI. 1, fig. 5) from the same at the middle portion of frond (or penul­ bed, those by KRASSILOV (1967, p. 107, timate pinna) with a prominent median pI. 9, figs. 1-2) from the Lower Cretaceous groove on the upper surface and thinly of Southern Primorye, and those by BELL winged along both lateral sides. Pinnae (1956, p. 63, pI. 14, fig. 4; pI. 19, fig. 4 ; elongate-oval or elongate-lanceolate in pI. 21, figs. 2, 3) from the Lower Creta­ form, flexible, more than 9 cm long and ceous of Western Canada. 2.2 cm wide at the widest portion and Cfr. Gleichenites porsildii recently des­ attached alternately to the rachis at an cribed by SAMYLINA (1976, p. 21, pI. 2, angle of 35 degrees, then bending out­ fig. 1) from the Lower Cretaceous (dated wards, the distance being 1.25 cm. Pinna as Aptian by her) of the Omsukchan axis slender and with a distinct median Coal-Field on the right bank of the Kol­ groove. Pinnules katadromic in order, yma is indistinguishable from our sterile set closely, rhomboidal in form, acumi­ specimens. nately pointed at apex, typically 1.2 cm Occurrence :-Common. long and 3 mm wide at the widest por­ Specimens:-BK6-028, BK6-063. tion, decurrent at base, distal half of margins serrate, serration typically 6-7 Family Dicksoniaceae in number and directed forwards. Nerves Sphenopteris-type, midnerve originating Genus Coniopteris BRONGNIART, 1849: 26 near the basiscopic base, slightly sinuous 686. Mesozoic plants front the Akaiwa Formation 265 and sending off 6-7 pairs of simple or with those described by LEBEDEV (1965) rarely once forking secondaries directed from the Upper Jurassic of the Zeia in forwards. The first basiscopic pinnules outline of pinnules with serrate margins, specialized, triangular in form, the apex venation, the form of first basiscopic sometimes bilobed and originating below pinnules and the position of sorus. the base of the pinna axis and distinctly This species has been regarded as one decurrent to form wings along both sides of the characteristic ones in the V AKHRA­ of main rachis. Fertile pinnae and pin­ MEEV'S Siberian Palaeo floristic Area. This nules, similar in form to sterile ones, but is the first record of Coniopteris saportana mostly reduced in size, 0.4-0.5 cm long from Japan. and 1.3 mm wide at the widest portion, Occurrence:-Probably common. in the largest one, more than 1 cm long Specimens:-BK6-031, BK6-037, BK6- and 7 mm wide at the widest portion. 042, BK6-048, BK6-092. Sori circular or oblong, variable in size, 0.2-1 mm across, one or rarely two in Family Pteridaceae? number on the distal part of each serra­ tion, or on the distal part of the acros­ Genus Adiantopteris V ASSILEVSKAJA copic secondary nerves in case of larger 1968: 49 pinnules. Several specimens were obtained. PI. We use Adiantopteris V ASSILEVSKAJA, 36, fig. 1 shows a part of sterile frond 1968 instead of Adiantites GOEPPERT, 1836, in which the first basiscopic pinnules are the meaning of which is confused. We clearly seen. PI. 38, fig. 2 shows a fertile describe new material of Adiantopteris pinna on the apical portion of a frond, sewardii and A. to),oraensis in which we attached remotely to the fairly thick include 'Adiantites sp. D' of KIMURA & rachis, 2 mm across. PI. 37, fig. 6 shows SEKIDO, 1976b. We rename Adiantites sp. two fertile pinnules enlarged presumably A, sp. Band sp. C of KIMURA, 1975 and on the proximal portion of a frond, 1 cm KIMURA & SEKIDO, 1976b as Adiantopteris long and 0.5 cm wide, deeply lobed, in sp. A, sp. Band sp. C respectively. which sori are terminated at the distal edge of each acroscopic secondary nerve Adiantopteris sewardii CY ABE) in each lobe, and the laminae, except the sterile parts, are somewhat reduced. V ASSILEVSKAJA Text-fig. 3 shows outline of sterile and PI. 36, figs. 1, 2; PI. 37, fig. 7A; Text.fig. 4 fertile pinnae, pinnules and their venation, and presumable transverse section of a Adiantites sewardi YABE; YABE, 1905, p. 39, rachis. pI. 1, figs. 1-7 (Nagdong Group,. Korea), Remarks:-The present specimens agree fig. 8 (Kami-Uchinami, an equivalent of the Oguchi formation) ; OISHI, 1940, p. 233, with Coniopteris saportana known from pI. 7, figs. 1,5 (Iwaidani and Kuwashima, various parts of East Siberia. The pres­ the Oguchi formation), fig. 6 (a reproduc­ ent specimens resemble HEER'S original tion of Y ABE'S pI. 1, fig. 3) ; ]Ai\:ICHEi\: & specimens in general outline of sterile KAHLERT, 1972, p. 966, pI. 1, figs. 2, 3, 5 pinnules and venation in which the secon­ (Jurasso.Cretaceous? of Mongolia). daries are directed forwards, but with Adiantites aff. sewardi YABE; VAKHRAMEEV, entire margins. 1958, p. 83, pI. 8, figs. 2, 3 (Lower Creta· The present specimens agree closely ceous of the Lena). 266 Tatsuaki KIMURA and SinJ·i SEKIDO

3e ~ 3g I----l o O.25em

I I I I 0 1 em 0 2em 3d 3a t I I 0 O.5em 3f

o O.5em

Text·fig. 3: Coniopteris saportana (HEER) VACHRAMEEV. a-d; sterile, e-f; fertile. a-b; a part of sterile frond (BK6-037 and BK6-048). c; showing outline and venation of normal pinnules, drawing from 3a. d; showing outline and venation of a first basiscopic pinnule, drawing from 3a. e; a fertile pinna fragment on the distal part of a frond, show­ ing outline and venation of pinnules, and position of sorus (BK6-031). f; a part of fertile pinnule probably on the proximal portion of a frond, showing outline and Yenation, with deeply lobed margins, and position of sorus (BK6-042). g; a presumable transverse section of rachis with a prominent median groove above, rounded below and lateral expansions due to wings of laminae above. 686. Mesozoic plants from the Akaiwa Formation 267 Adiantopteris sewardii (YABE) V ASSILEVS­ Adiantopteris toyoraensis (OISHI) KAJA; KRASSILOV, 1967, p. 123, pI. 20, figs. 1, 2 (Lower Cretaceous of Southern VASSILEVSKAJA Primorye). PI. 36, fig. 3; Text-fig. 5

Description :-Rachis slender, 0.5 mm Adiantites toyoraensis OISHI; OISHI, 1931, p. 11, thick, with smooth surface, bearing subop­ (name only) ; 1940, p. 235, pI. 7, figs. 2, posite lateral pinnules. Lateral pinnules 2a, 3 (non figs. 4, 4a) (Upper Jurassic with short stalk, laminae somewhat ine­ Kiyosue formation); JANICHEN & KAH­ quilateral, broadly oblanceolate in form, LERT,1972, p.967, pI. 2, figs. 1,2 (Jurasso­ with cuneate base, distal margin irregu­ Cretaceous? of Mongolia). larly double-serrate or lacerate, and distal Adiantites sp. D; KIMURA & SEKIDO, 1976b, p. 358, pI. 36, fig. 4; text-fig. 8 (Osugi­ half of lateral margins shallowly serrate. dani, the Akaiwa Formation). Nerves usually prominent, arising from two in the stalk, branching throughout Description :-Incompletely preserved and showing little tendency to form strong pinnate lateral pinnules, bases missing. marginal nerves, 16-18 in number per cm Laminae small, ovate in form, with a in density at the middle part of lamina. median sinus and with serrate outer Apical pinnules and fructification not margin, 2 cm long and about 1.5 cm wide known. at the widest portion. Nerves divergent Several detached pinnules and one frag­ from the point of attachment, repeatedly ment of a frond were obtained. PI. 37, forking dichotomously, 18 per cm in fig. 7A (BK6-046) shows a fragment of a density at the middle part of lamina. frond with three broken pinnules and PI. Fructification not known. 36, fig. 2 (BK6-003) and fig. 1 show de­ Text-fig. 5 shows two pinnate lateral tached pinnules. Text-fig. 4 shows outline pinnules and their venation. of pinnules and their venation drawn from Remarks:-The present incomplete BK6-046 and BK6-003 respectively. specimen agrees in pinnule outline and Remarks:-This species is less common venation with the original specimens des­ in the Akaiwa Formation than the Oguchi cribed by OISHI from the Upper Jurassic formation. The present specimens, though Kiyosue formation, Yamaguchi Prefecture. incomplete, agree with Y ABE'S original This species resembles Adiantopteris specimens, especially with his pI. 1, fig. 3, gracilis V ASSILEVSKAJA known widely except the venation. All nerves appear from the Upper Jurassic-Lower Creta­ to originate from the top of stalk in ceous of East Siberia (V ASSILEVSKAJA, Y ABE'S illustration, while in the present 1957, 1966; V ASSILEVSKAJA & PAVLOV, specimens, nerves are arising two in the 1963; SAMYLINA, 1976). stalk, then branching throughout, as the Occurrence :-Rare. nerves of Ginkgo biloba do. We imagine Specimen:-BK6-081. that the veins are imperfectly represented in YABE'S figures. Occurrence :-Not common. Unclassified ferns Specimens:-BK6-003, BK6-046 and many small fragments of pinnules. Form-genus Cladophlebis BRONGNIART, 1849: 105

From the Akaiwa Formation and its l 268 Tats~wki J{li\WRA and Sinji SEKIDO

2cm 2cm (r rn 6a 6b ~ ffrn/J o o O.5cm

7c

o 2cm

Text-figs. 4-7. 4; Adiantopteris sewardii (YABE) VASSILEVSKAJA. 4a; a lateral pinnule preserved almost completely, drawn from PI. 36, fig. 2 (BK6-003), showing outline and venation of pinnule. 4b; a part of pinna with three incompletely preserved pinnules with short stalk. 5; Adiantopteris toyoraensis (OISHI) VASSILE\,SKAJA, showing two lateral pinnules and their venation, drawn from PI. 36, fig. 3 (BK6-0S1). 6; Cladophlebis ex gr. williamsonii (BRONGNIART) BRONGNIART. 6a; three detached pinnae drawing from PI. 37, fig. 2 (BK6- 033), showing general outline of pinnules. 6b; showing venation drawing from 6a. 7; Raphaelia diamensis SEWARD. 7a; showing venation (BK6-017). 7b-c; showing outline of pinnules, the first pair of lobes is distinctly specialized in form and each lamina is decur­ rent to axis to form a wing (BK6-025 and BK6-047). 686. Mesozoic plants from the Akaiwa Formation 269 equivalents, the following Cladophlebis Description :-Sterile frond probably species have been known; Cladophlebis ex bipinnate, unknown size. Pinnae set gr. denticulata (BRONGNIART) NATHORST, closely, long and narrow, nearly parallel­ C. distans (HEER) YABE (non FONTAINE), sided, more than 8 cm long and 1.6 cm C. williamsoni (BRONGNIART) var. tenui­ wide and attached to the rachis at an caulis THOMAS and C. sp. angle of 30-45 degrees. Pinnules set We recently obtained good specimens closely, broadly triangular in form, falcate, from Bettokuzure of the Akaiwa Forma­ entire, basiscopic margin usually rounded, tion, assignable to C. ex gr. williamsonii attached by their whole base at a wide and regarded here C. williamsoni var. angle, mostly with expanded base and tenuicaulis formerly described by us from subacutely pointed apex, typically 1.2 cm the same locality as C. ex gr. williamsonii. long and 0.6 cm wide at base. Midnerve Cladophlebis ex gr. denticulata is similar persisting to the tip, sending off twice in form to C. ex gr. williamsonii, but it forking secondaries, 3 or 4 pairs on both is easily distinguishable from each other sides of a midnerve. (No fertile material by examining their venation; in C. ex gr. available). denticulata, the secondaries are once fork­ Text-fig. 6a drawn from the specimen ing dichotomously except the first pair shown in PI. 37, fig. 2 shows. outline of and in C. ex gr. williamson ii, they are pinnules and Text-fig. 6b shows detailed twice forking in general. venation. By our finding of its fertile pinnae from Remarks:-It would be noteworthy that the Oguchi formation, Cladophlebis distans such one of the older types of Cladophlebis is to be redescribed by us as Osmundopsis species bearing large-sized pinnules as distans (KIMURA & SEKIDO, 1977 MS) and this species is fairly abundant in the also C. sp. is at present to be referable Akaiwa Flora, because they have not been to some Gleichenites species (KIMURA & found from the coeval floras in the Outer SEKIDO, 1977 MS). Zone of Japan. The present specimens agree in form and venation with a common form of Cladophlebis ex gr. williamsonii sterile Todites williamsoni, though there may be Cladophlebis species of this form (BRONGNIART) BRONGNIART in the Upper Jurassic and Lower Creta­ PI. 37, fig. 2; Text·fig. 6 ceous. Cladophlebis williamsoni var. tenuicaulis Cladophlebis williamsoni (BRONGNIART) BRO. described by us from the same locality :"IGNIART var. tenuicaulis THOMAS; KIMU· should now be included into the category RA & SEKIDO, 1976b, p. 354, pI. 36, figs. of C. ex gr. williamsonii. 5, 6; pI. 38, fig. 6 ; text.fig. 5 (Bettokuzure, the Akaiwa Formation). Occurrence :-Common. SPecimens:-BK6-033, BK6-034 and HARRIS (1961) listed a large number of many pinna fragments. comparable specimens from many regions including Japan and ranging from the Upper Triassic through the Jurassic. Genus Raphaelia DEBEY & V AKHRAMEEV (1958) and V AKHRAMEEV ETTINGSHAUSEN, 1859: 219 & DOLUDENKO (1961) gave Cretaceous references. In our previous paper (1976b), we des- 270 Tatsuaki KIMURA and Sinji SEKIDO cribed Raphaelia sp. A and sp. B. Re­ wing, 0.3 mm wide, other lobes semi­ cently we obtained new material among circular in form. Midnerve distinct, which we discriminated a well-known slightly sinuous, persisting to the tip, Raphaelia diamensis. sending off twice or once forking second­ aries at an acute angle, each lobe receiv­ ing one secondary nerve. (No fertile speci­ Raphaelia diamensis SEWARD mens found). PI. 37, fig. 1; PI. 38, fig. 1; Text.fig. 7 PI. 38, fig. 1 and PI. 37, fig. 1 show the upper and lower surfaces of pinnae res­ Raphaelia diamensis SEWARD: SEWARD, 1911, pectively and Text-fig. 7 shows outline p. 15, pI. 2, figs. 28, 29 (Middle Jurassic of pinnules and venation in detail. of Chinese Dzungaria); V AKHRAMEE\', Remarks:-The present specimens agree 1958, p. 100, pI. 21, figs. 2-4; pI. 22, figs. with the original ones described by 1-3; pI. 23, figs. 1-6; pI. 24, fig. 1 (Upper Jurassic of the Lena); VAKHRAMEEV & SEW ARD from the Middle Jurassic of DOLLDENKO, 1961, p. 75, pI. 6, fig. 5; pI. Chinese Dzungaria and those by several 27, fig. 1; pl. 28, fig. 1; pI. 30, fig. 4; Russian palaeobotanists from the Upper text·fig. 22 (Upper Jurassic of the Bureja) ; Jurassic rocks in VAKHRAMEEV'S Siberian SA~IYLI"A, 1963, p. 79, pI. 9, figs. la, 2 Palaeofloristic Area in past two decades, (Upper Jurassic of the Aldan) ; 1964b, p. but the Siberian pinnules are somewhat 69, text·fig. 8 (Upper Jurassic of the shorter and broader than those of ours. Zyrianka Coal.Field); LEBEDEV, 1965, p. In V AKHRAMEEV'S Siberian Palaeo­ 87, pI. 14, fig. 2; pI. 15, fig. 3 (Upper floristic Area, this species appears to be Jurassic of the Zeia). restricted in the Middle to Late Jurassic Raphaelia aff. diamensis SEWARD; SAMYLIKA, 1963, p. 80, pI. 2, figs. 8-11; pI. 7, fig. 5 floras, while in Japan this species is abun­ (Upper Jurassic of the Aldan). dant in the early Neocomian Oguchi flora (KIMURA & SEKIDO, 1977 MS) and common Description :-Several incomplete pinna in the late Neocomian Akaiwa Flora, but fragments. Pinnae elongate-oval or elon­ has not been recorded in the coeval floras gate-lanceolate in form, about 1.5 em wide in the Outer Zone of Japan. at the widest portion. Pinnules set some­ Occurrence :-Common. what remotely, elongate-triangular in Specimens:-BK6-017, BK6-025, BK6- form. 1 em long and 0.25 cm wide at base, 041, BK6-047. bluntly or acutely pointed at apex, strong­ ly constricted at base, then decurrent to the axis to form a wing and attached at Bennettitales a wide angle to the axis, upper surface strongly convex; margins distinctly lobed, Genus Dictyozamites OLDHAM & lobes 6-7 in number on each side, with MORRIS, 1963: 37 rounded apex directed forwards, the first pair of lobes mostly specialized, acro­ As was shown in detail in our previous scopic ones rectangular in form, largest paper (KIMURA & SEKIDO, 1976a), the in size, 0.27 mm long and 0.13 mm wide Oguchi formation yields abundant and and less directed forwards, basiscopic varied Dictyozamites species, while from ones circular or triangular in form, some­ the superjacent Akaiwa Formation, only times reaching 0.2 mm in diameter, often D. cfr. cordatus (KIMURA & SEKIDO, 1976b) decurrent along the pinna axis to form a and a new type here described resembl- 686. Mesozoic plants from the Akaiwa Formation 271 ing D. obliqllllS are known in rare occur­ From the Akaiwa Formation, the fol­ rence. lowing Nilssonia species have been des­ cribed; Nilssonia kotoi (YOKOYAMA) OISHI, N. lobatidentata V ASSILEVSKAJA and N_ Dictyozamites cfr. obliqllllS SAMYLINA nipponensis YOKOYAMA. In addition, we PI. 38, fig. 5; Text·fig. 8 here describe Nilssonia schmidtii (HEER) SEWARD. Comparable specimens: Dictyozamites obliquus These Nilssonia species are common to SA:\IYLINA; SAMYLINA, 1964a, plate, figs. those of the coeval floras in V AKHRA­ 10, 11 (Lower Cretaceous of Central Pri· MEEV'S Siberian Palaeo floristic Area, morye). except N. kotoi. But N. kotoi is similar Description :-Isolated pinnae, elongate­ in form to N. sinensis Y ABE & OISHI triangular in form, upper margin straight known from the Jurassic of Northern and lower one arched, both apex and China and N. borealis SAMYLINA from base missing, more than 3 cm long and the Lower Cretaceous Siliap formation in 0.8 cm wide at basal part. Nerves fine, the Zyrianka Coal-Field. anastomosing to form fine meshes, upper These Nilssonia leaves from the Akaiwa nerves straight, parallel to the upper Formation are smaller in size in general margin but lower nerves divergent to the than those from the underlying Oguchi lower margin. formation. Text-fig. 8 drawn from one of the specimens shown in PI. 38, fig. 5 show Nilssonia schmidtii (HEER) SEWARD venation in detail. Remm'ks:-The present specimens are PI. 38, fig. 6; Text-fig. 9 characterized by the nerves in which upper ones are straight and parallel to Anomozamites schmidtii HEER; HEER, 1876, the upper margin and lower ones are p. 100, pI. 23, figs. 2, 3; pI. 21, figs. 4-7 (Jurasso.Cretaceous of the Bureja and the divergent. Such nerves as in the present Amur). specimens has not yet been recorded Nilssonia schmidtii (HEER) SEWARD; SEWARD, among the known Dictyozamites species, 1912, p. 27, pI. 2, figs. 11, 12, 14 (Jurasso­ except D. obliquus. Cretaceous of the Tyrma and the Umalta) ; Therefore the present specimens might KRYSHTOFOVICH, 1916, p. 114, pI. 10, fig. be referable to Dictyozamites obliquus 5 (Lower Cretaceous of Southern Pri­ originally described by SAMYLINA from morye); V AKHRAMEEV & DOLlJDEl'KO, the Lower Cretaceous of the Bikin River 1961, p. 96, pI. 43, figs. 5, 6 (Jurasso­ area, Central Primorye, but we here Cretaceous of the Bureja) ; LEBEDEv, 1965, reserve identifying the present ones fully p. 92, pI. 22, fig. 3b; pI. 23, fig. 2; pI. 24, fig.. 1 (Upper Jurassic of the Zeia). to SAMYLINA'S species because they are too imperfect. Description :-Several isolated leaf-frag­ Occurrence :-Rare. ments. Leaves more than 4.7 cm long Speci71len:-BK6-090 (one slab only). and 2.8-1.6 cm wide at the middle portion of lamina. Lamina covering the upper Cycadales surface of rachis, irregularly segmented, segments 0.5-1.3 cm wide, quadrilateral in Genus Nilssonia BRONGNIART, 1825: 200 form, lateral and distal margins of narrow 272 Tatsuaki KIMURA and Sinji SEf(IDO

2em

o

8 "ill I I o lem

o

I I o o 1. em 686. Mesozoic plants from the Akaiwa Formation 273

segments rounded, but irregularly and cluding YOKOYAMA'S Glossoza71lites hohe­ broadly undulated in broad segments. neggel'i with her some doubt, and des­ Nerves fine, simple, parallel, 26-34 per cribed Butejia ensiform is (HEER) (p. 135, cm in density. pI. 12, figs. 1-3), from the Upper Jurassic Remarks:-The present specimens are in the upper course of Amur. referable to Nilssonia schmidtii in general This genus is a form-genus known only outline. Such specimens regarded as by its external pinnate fronds. The ex­ Nilssonia schaumburgensis by KRASSILOV ternal appearance of its pinnae reminds (1967) from the Lower Cretaceous of us of some Podozamites leaves, but it is Southern Primorye as his pI. 57, figs. 3, generally distinguished from Podozamites 4, 6 resemble the present ones, but they by its apparently dichotomously forking are distinguishable from the present ones nerves near the base. in that in KRASSIL ':lV'S specimens the In 1965 LEBEDEV described Butejia bure­ incisions of laminae are mostly not reach­ jensis from the Upper Jurassic along the ing to the rachis, or if do so, the seg­ Zeia, including as synonymy PRYNADA'S ments are different in form those of N. Glossozamites burejensis and DOBRUSK~NA'S schmidtii. Butejia ensiform is excluding her pI. 12, Several specimens regarded by us as fig. 2. Nilssonia nipponensis from the same Very recently SAMYLINA (1976) des­ locality (KIMURA & SEKIDO, 1976b, p. 361, cribed Butejia obliqua as a new species pI. 37, fig. 2; text-fig. 17) are similar in from the Lower Cretaceous bed (dated form to the present ones but the distal as Aptian by her) of the Omsukchan margins of their segments are mostly Coal-Field in the right bank of Kolyma. finely dentate and not rounded as those of the present ones. Butejia? sp. Occurrence :-Common. Text-fig. 10 Specimens:-BK6-018, BK6-044, BK6- 080. Description :-A detached pinna, base missing, elongate-ovate in outline, 8.3 cm long and 3.4 cm wide ,at the widest por­ Unclassified cycadophyte tion, apex presumably rounded: Nerves Genus Butejia DOBRUSKINA, 1964: 135 originating radially from the small area at base, dichotomously forking near base~ In 1964, DOBRUSKINA established this parallel on the most part and converging genus as a new cycadophyte, based on a near apex, apex unknown, 16 per cm in part of HEER'S Podozamites ensiformis density at the middle portion of lamina. ' (HEER, 1878, p. 6, pI. 2, figs. 5, 6) and Text-fig. 10 shows pinna outline and PRYNADA'S Glossozamites ensiform is, in- venation.

Text-figs. 8-12. 8; Dictyozamites cfr. obliquus SA;\IYLlNA, showing venation in detail, drawing from One of the incomplete pinnae shown in PI. 38, fig. 5 (BK6-090). 9,; Nilssonia schmidtii (HEER) SEWARD, showing outline of segments and venation, drawing partly from BK6-018. 10; Butefia? sp., showing pinna outline and venation, drawing from BK6- 029. 11; Ginkgoites paradiantoides (SAMYLINA), sh'owing venation and general outline of lamina, drawing from PI. 38, fig. 8 (BK6-035). 12; Arctobaiera? 'sp., showing venation, drawing from PI. 38, fig. 9 (BK-106). 274 Tatsuaki KIMURA and Sinji SEKIDO Remarks:-The present pinna would Ginkgoites paradiantoides belong to Butefia owing to its venation. (SAMYLINA) n. comb. But it does not agree both in external outline and in density of nerves with PI. 38, figs. 7, 8; Text-fig. 11 such three species hitherto known in Similar specimens: Ginkgo paradiantoides V AKHRAMEEV'S Siberian Palaeofloristic SAYMYLINA; SA~IYLINA, 1967, p. 138, pI. Area as B. burejensis, B. ensiformis and 2, figs. 2-5; pI. 3, figs. 1-11; pI. 4, figs. B. obliqua. However, owing to the in­ 9-10; pI. 6, fig. 7a; pI. 8, fig. 7b (Lower completeness of present material, we at Cretaceous of the Zyrianka Coal-Field). present regard the present one hastily as Ginkyo pluripartita SClIIMPER; SA:vIYLINA13, Butefia? sp., though we should make here 1964, p1.l7, fig. 2b (Ditto). with our anxiety an additional remark Description :-Leaves long petioled, peti­ that the present one resembles closely ole 4-5cm long. Laminae semi-circular with such Ferganiella species regarded by a basal angle of 180 degrees, divided by a Russian palaeobotanists as having Podoza­ deep median sinus reaching to the top of mites affinity, as F. LanceoLata BRICK des­ petiole into two halves with truncated or cribed by BARANOV A et al. (1975, p. 133, irregularly lobed apical margin. Nerves pl. 34, figs. 7, 8) from the Jurassic of the divergent, dichotomously forking at all eastern part of Caspian Basin. levels on the apical half of lamina. Occurrence :-Rare (at present). Remarks:-It is unfortunate that we SPecimen:-BK6-029. cannot give details of the cuticle because it is not preserved in the present flora. The present specimens would be refer­ Ginkgoales able almost to SAMYLINA'S Ginkgo para­ Genus Ginflgoites SEWARD, 1919: 10 diantoides described from the Zyrianka Coal-Field. In addition to such Ginkgoites species Occurrence :-Not rare. as G. digitata, G. huttonii and G. sibirica SPecimens:-BK6-035, BK6-085. described by us (KIMURA & SEKIDO, 1976b) from the Akaiwa Formation, a new type Czekanowskiales leaves referable to Ginflgoites paradian­ toides are described here. Following Genus Arctobaiera FLORIN, 1936: 118 SEW ARD (1919), we have used the generic Arctobaiera? sp. name Ginkgoites, instead of Ginkgo used by modern palaeobotanists. PI. 38, fig. 9; Text-fig. 12

Explanation of Plate 36

1. Coniopteris saportana (HEER) VACI-IRA~1EE\'; sterile part of a frond; in association with two incomplete pinnules of Adiantopteris sewardii (YABE) VASSILEVSKA)A. (BK6-037), x 2. 2. Adiantopteris sewardii (YABE) VASSILEVSKA)A; one nearly complete pinnule and two incom­ pletely preserved pinnule bases. (BK6-003), x 2. 3. Adiantopteris toyoraensis (OISI/I) VASSILEVSKA)A; (= Adiantites sp. D in KIMURA & SEKIDO, 1976b) ; two pinnate sterile pinnules. (BK6-081), x 2. 4-7. Protodammara sp. ; cone scales. (4; BK6-001, 5-7; BK6-040), x 3. 8-9. Carpolithes sp. ; seeds of Ginkgoites?; (BK6-040), x 3. KIMURA and SEKIDO: Mesozoic plants from the Akaiwa Formation Plate 36 686. Mesozoic plants from the Akaiwa Formation 275

Description :-A fragment of a leaf­ Conifers in the Akaiwa Formation have bundle composed of four segments, unit­ usually been neglected because the speci­ ing near base. Segments long and narrow, mens give little palaeobotanical informa­ about 7 cm long, variable in width, rang­ tions, but we point out that there are ing 5-Smm wide at the middle portion, fairly numerous species in the flora. overlapping each other laterally, narrow­ ing gradually towards the unknown base and abruptlY towards unknown apex. Form-genus Elatocladus HALLE, em. Nerves 5-7 in number at basal part, then HARRIS, 1969: 249 dichotomously forking, as many as twice in number at middle portion, not converg­ Elatocladus sp. C ing at apex. Text-fig. 12 drawing from PI. 38, fig. 10 PI. 3, fig. 9 shows outline of leaves and their venation. Description:-A single specimen of a Remarks:-One specimen with its coun­ coniferous shoot. Leaves dorsiventrally terpart was obtained. JUdging from its set closely, long and narrow, nearly form, this specimen might represent a parallel-sided throughout, constricted at leaf-bundle consisting of more than four base, very shortly petioled, with bluntly segments and might belong to Arctobaiera pointed at apex, typically 0.7 cm long and or Phoenicopsis of Czekanowskiales. At 0.9 mm wide, attached to the axis at an present we provisionally place it Arcto­ angle of about 60 degrees, and longitu­ baiera? sp. dinally traversed by an indistinct median The present specimen would remind us nerve. of Arctobaiera florinii originally described Remarks:-Though we have nothing to by LEBEDEV (1974, p. SO, pI. 20, fig. 2; say about its affinity because of the in­ pI. 21, figs. 1-4; pI. 22, fig. 1 ;text-fig. 37) completeness of material, the present from the Lower Cretaceous of Western specimen would remind us of such taxo­ Priokhotie. diaceous genera as Sequoia or Taxodium, Occurrence:-Rare. so far as its external appearance is con­ Specimen:-BK-106 (its counterpart, cerned. BK -133, collected by C. SMILEY, Professor Occurrence :-Fine fragments are com­ of the University of Idaho, U. S. A., in mon. 1974). SPecimen:-BK6-009.

Coniferales Elatocladus sp. D

Besides varied and abundant Podoza­ PI. 38, fig. 11 mites species, a few conifer remains such as Elatocladus sp. A and sp. B, and Pityo­ DescriptiOlL'-A single incomplete con­ phyllum lindstroemii have been reported in iferous shoot. Leaves linear lanceolate the Akaiwa Flora (KIMURA & SEKIDO, in form, constricted at base and decurrent 1976b). In addition, we describe here two to the axis, bluntly pointed at apex, 0.5. types of coniferous shoots, and several cm long and 1 mm wide at the widest coniferous cone-scales probably belonging portion, and longitudinally traversed by a to a same species but uncertain affinities. prominent median nerve. 276 Tatsuaki KIMURA and Sinji SEKIDO Remarks:-Palissya sp. described by and Dammara minor by HOLLICK (1906) YOKOYAMA (1889, p. 64, pl. 9, fig. 11) from from the Cretaceous of New York. But Kuwashima (formerly Shimamura) of the these American specimens differ from the Oguchi formation somewhat resembles the present ones in having apiculate apices. present one in external appearance. Full analysis and discussion of the The present specimen is included in present specimens will be made after a Elatocladus in the sense in which that more complete study of our new material. comprehensive genus was proposed by This generic name, Protodammara itself HALLE. does not always mean its araucarian Occurrence:-Fine fragments of leaves affinity. are common. Occurrence :-Not rare. Specimen:-BK6-039. Specimens:-BK6-00l, BK6-040.

Form-genus Protodammara HOLLICK & Unclassified seed JEFFREY, 1906: 199 Form-genus Carpolithes SCHLOTHEIM, Protodammara sp. 1820: 418

PI. 36, figs. 4-7 Carpolithes sp.

Description :-Several detached kite-like PI. 36, figs. 8, 9 cone scales. Cone scales 0.8-1.0 cm long and 0.7-0.9 cm wide above, abruptly nar­ Description :-SeveraJ incomplete seeds. rowed from about middle to the base, not Seeds or seed-stones ovate, sharply edged, apiculate but broadly undulate terminally, rounded at base and sharply beaked at seed scars three in number, crescentically apex, 0.9 cm long and 0.6 cm wide at the arranged above the middle and approxi­ widest portion. mately in the broadest part of the scale, Remarks:-The present specimens re­ with the central one slightly higher up semble the following in external appea­ than the laterals. rance; seeds regarded by HEER (1876, p. Remarks:-In external appearance, the 58, pI. 11, figs. 13-16) as belonging to present specimens somewhat resemble Ginkgo sibirica from the Jurassic of Ust­ Protodammara speciosa originally des­ Balei; Carpolithes ginkgoides by YOKO­ cribed by HOLLICK & JEFFREY (1906, 1909) YAMA (1889, p.65, pI. 10, figs. 20-23) from

Explanation of Plate 37

1. Raphaelia diamensis SEWARD; a pinna fragment (back view) ; (BK6-025), x 3. 2. Cladophlebis ex gr. williamsonii (BROJ'iGNIART) BRONGNIART; sterile parts of fronds piled up together. (BK6-033), x 1. 3. Gleichenites porsildii SEWARD; fertile pinnae with comparatively thick rachis. (BK6-028), x 2. 4-5. Gleichenites nipponensis OISHI; incomplete fertile pinna fragments. (BK6-010), x 2.5. 6. Coniopteris saportana (HEER) V ACI-IRAMEEV ; fertile pinna fragment. (BK6-042), x 3. 7. A; Adiantopteris sewardii (Y ABE) V ASSILEVSKAJA; two pinnate pinnules attached to the rachis with short stalks. B; Nilssonia lobatidentata VASSILEVSKAJA; (for details, see KIMURA & SEKIDO, 1976a, b). (BK6-046), x 2. KIMURA and SEKIDO: Mesozoic plants from the Akaiwa Formation Plate 37 686. Mesozoic plants from the Alcaiwa Formation 277

Ozo of the Oguchi formation apart from Cleichenites de los sedimentos Baque­ their long beaks as shown in his figures; roensis de Santa Cruz, Patagonia. Ameg­ Allicospennum burejense by KRASSILOV hiniana, T. 2, nr. 8, p. 141-148, pis. 1-3. (1972, p. 39, pI. 5, figs. 8-10; text-fig. 5d, -- (1962b): Cleichenites juliensis n. sp. del g) from the Jurasso-Cretaceous of Bureja Jurasico Medio de Santa Cruz, Patagonia. Basin; seeds regarded by HARRIS et a!. Ibid., nr. 10, p. 187-190, pI. 1. (1974, p. 72, fig. 22C, D) as belonging to HOLLICK, A. (1906): The Cretaceous flora Ginkgo huttoni from the Middle Jurassic of Southern New York and New England. of Yorkshire. Mon. U. S. Ceol. Surv., vol. 50, p. 1-219, incl. pis. 1-40. Thus it would be quite possible that the -- & JEFFREY, E. C. (1906): Affinities of present specimens belong to Ginkgoites. certain Cretaceous plant·remains com­ Occurrence :-Rare. monly referred to the Dammara and Specimen :-BK6-040 (one slab only). Brachyphyllum. Amer. Nat., vol. 40, p. 189-216, pis. 1-3. -- & -- (1909): Studies of Cretaceous References coniferous remains from KreischerviIIe, New York. Mem. N. Y. Bot. Card., vol. R-\RANOVA, Z. E., KIRICHKOVA, A.I. & ZAUER, 3, p. 1-76, pis. 1-29. V. V. (1975): Stratigraphy and flora from Jii.HNICIIEN, H. & KAHLERT, H. (1972): Vber the Jurassic of the eastern part along the eine mesozoische Flora aus der mongol is­ Caspian Basin. VNICRI, Leningrad, Bull. chen Volksrepublik. Ceol., Jahr. 21, H. 332, p. 1-190, incl. pis. 1-34. (in Russian). 8, p. 964-1001, incl. pis. 1-6. BELL, W. A. (1956): Lower Cretaceous floras KIMURA, T. (1958): On the Tetori flora (Pt. of Western Canada. Ceol. Surv. Canada, 1). Mesozoic plants from the Kuzuryu Mem. 285, p. v+1-331, incl. pis. 1-85. Subgroup, Tetori Group, Japan. Bull. DOBRUSKINA, I. A. (1964): New Jurassic Sen. High Sch., Tokyo Univ. Educ., II-2, cycadophyte·s from the upper course of p. 1-47, pis. 1-4. Amur. jounl. Palaeont., Acad. Sci. USSR, -- (1975): Middle·late early Cretaceous 1964-no. 2, p. 132-141, pis. 12-13. (in plants newly found from the upper course Russian). of the Kuzuryu River area, Fukui Pre­ HARRIS, T. M. (1961) : The Yorkshire Jurassic fecture, Japan. Trans. Proc. Palaeont. flora I. Thallophyta-Pteridophyta. Brit. Soc. japan, N. S., no. 98, p. 55-93, pis. A;fus. (Nat. Hist.), p. ix+1-212. 5-8. -- (1969): Naming a fossil conifer. j. Sen -- & SEKIDO, S. (1976): Dictyozamites and Mem. Vol., Bot. Soc. Bengal, p. 243-252. some other cycadophytes from the early --, MILLINGTON, W. & MILLER, J. (1974): Lower Cretaceous Oguchi Formation, the The Yorkshire Jurassic flora, IV. Gink­ Itoshiro Group, Central Honshu, Japan. goales and Czekanowskiales. Brit. Mus. Ibid., no. 101, p. 291-312, pIs. 30-32. (Nat. Hist.), p. viii+1-150, pis. 1-8. -- & -- (1976b): Mesozoic plants from HEER, O. (1876): Beitrage zur Jura-Flora the Akaiwa Formation (Upper Neoco· Ostsibiriens und des Amurlandes. Mem. mian), the Itoshiro Group, Central Hon· Acad. Imp. Sci., St.-Petersb., ser. 7, T. shu, Japan. Ibid., no. 103, p. 343-378, 22, no. 12, p. 1-122, pis. 1-31 (Fl. foss. pis. 36-39. arct., 4-2). -- & -- (1977MS): The Oguchi Flora ---- (1878) : Beitrage zur fossilen Flora (Early early Cretaceous) in the Inner Sibiriens und des Amuriandes. Ibid., T. Zone of Japan. 25, no. 6, p. 1-58, pis. 1-15 (Fl. foss. arct., KRASSILOV, V. A. (1967): Early Cretaceous 5-2) . flora from Southern Primorye and its HERBST, R. (1962a): Sobre les especies de significance for stratigraphy. Far East 278 Tatsuaki KIMURA and Sinji SEKIDO Ceol. Inst., Siber. Br., Acad. Sci. USSR, the west of the Kolyma River (Zyrianka Moscow, p. 1-248, pIs. 1-93. (in Russian). Coal-Basin), Pt. 1. Palaeobot., Koma/ov -- (1972): Mesozoic flora from the Bureja Bot. Inst., Acad. Sci. USSR, ser. 8 (Pal­ (Ginkgoales and Czekanowskiales). Far aeobot.), vol. 5, p. 41-78, pIs. 1-18. (in East Ceo!. Inst., Far East Sci. Centre, Russian). Acad. Sci. USSR, p. 1-151, incl. pIs. 1- -- (1967): Ditto. Pt. 2 Ginkgoales, Coni­ 3-1. (in Russian). ferales, General Chapters. Ibid., vol. 6, KRYSHTOFOVICH, A. N. (1916): Material for p. 133-175, pIs. 1-14. (in Russian). the Jurassic flora of Ussuriland. Trav. -- (1976): The Cretaceous flora of Omsuk­ Mus. Ceol. Min., St.-Petersb., vol. 2, no. chan (Magadan District). Komalov Bot, -1, p. 81-140, pIs. 7-11. Inst., Acad. Sci. USSR, Leningmd, p. 1- LEBEDEv, E. L. (1965) : Late Jurassic flora from 206, incl. pIs. 1-48. (in Russian). Zeia and boundary between Jurassic and SEW ARD, A. C. (1910): Fossil plants, A text­ Cretaceous. Ceol. Inst., Acad. Sci. USSR, book for students of botany and geology, Trans., vol. 125, p. 1-142, pIs. 1-36. (in vol. 2, p. xxii+1-624. Cambridge. Russian). "- (1911): Jurassic plants from Chinese -- (1974): Albian flora and Lower Creta­ Dzungaria, collected by Prof. OBR UTSCHEW. ceous stratigraphy of West Priokhotie. Mem. Com. Ceol., N. S., L. 75, p. 31-61, Acad. Sci. USSR, Trans., vol. 254, p. 1- pIs. 1-7. 147, incl. pIs. 1-31. (in Russian). -- (1912): Jurassic plants from Amurland. OISI-II, S. (1931): The Mesozoic plants, in Ibid., L. 81, p. 17-34, pIs. 1-3. Iwanami's Geological and Palaenotological -- (1919): Fossil plants, A text-book for Series, Tokyo. p. 1-91. (in Japanese). students of botany and geology, vol. 4. -- (1940): The Mesozoic floras of Japan. p. xvi+1-543, Cambridge. Journ. Fac. Sci., Hokkaido Imp. Univ., vol. -- (1926): The Cretaceous plants-bearing 5, nos. 2-4, p. 123-480, pIs. 1-48. rocks of Western Greenland. Philos. SAMYLlNA, V. A. (1963): Mesozoic flora of Trans. Roy. Soc., London, ser. B, vol. 215, the lower course of the Aldan River. p. 1-174, pIs. 4-12. Palaeobot., Komalov Bot. Inst., Acad. Sci. -- & CONWAY, V. (1935): Additional Cre­ USSR, ser. 8 (Palaeobot.), vol. 4, p. 59- taceous plants from Western Greenland. 138, pIs; 1-37. (in Russian). K. svensk. Vet.-Acad. Hand!., Stockholm, -"-" (1964a): Lower Cretaceous plants from Bd. 15, no. 3, p. 1-41, pIs. 1-6. the Central Sikhota-Alin. Jourii. Bot., V AKHRAMEEV, V. A. (1958): Stratigraphy Acad. Sci. USSR, vol. 49, p. 1286-1287. and fossil plants from the Jurassic and (in Russian). Cretaceous deposits ot" the Vi lui Basin -- (1964b): Mesozoic flora of the area to and Vercho jansk Foredeep. Reg. Stratigr.

Explanation of Plate 38

1. Raphaelia diamensis SEWARD; pinnules with convex upper surface (surface view). (BK6-047), x2. 2. Coniopteris saportana (HEER) V ACHRAl\IEEV ; an incomplete fertile pinna. (BK6-031), x 3. 3-4. Cleichenites nipponensis OISHI; incomplete fertile pinna fragments. (BK6-010), x 2.5. 5. Dictyozamites cfr. obliquus SAMYLlNA; two incomplete pinnae isolated. (BK6-090), x 2. 6. Nilssonia schmidtii (HEER) SEWARD; (BK6-044), x 2. 7 -8. Cinkgoites paradiantoides (SAMYLINA) comb. nov.: (7; BK6-0SS, 8; BK6-035), xL 9. Arctobaiera:? sp.; (BK-106), xL 10. Elatocladus sp. C; (BK6-039), x 3. 11. Elatocladus sp. D; (BK6-009), x 2. KIMURA and SEKIDO: Mesozoic plants from the Akaiwa Formation Plate 38 686. Mesozoic plants from the Akaiwa Formation 279

USSR, Ceol. Inst., Acad. Sci. USSR, vol. -- (1968) : New late Mesozoic ferns from 3, p. 1-128, pis. 1-32 (in Russian). Yakutia, in 'New genera of ancient plants -- & DOLuDE;-;Ko, M. P. (1961): Upper and invertebrates in USSR, vol. 2, pt. 1'. Jurassic and Lower Cretaceous flora of All Union Sci. Rep., Ceol. Ins!., Min. Ceol. the Bureja Basin and its significance for USSR, p. 49-51, pI. 16. (in Russian). stratigraphy. Ceol, Inst., Acad. Sci. -- & PAVLOV, V. V. (1963): Stratigraphy USSR, Trans., vol. 54, p. 1-135, pis. 1-60. and flora from the Cretaceous beds of (in Russian). Lena·Olenek region of Lena Coal-Basin. VASSILEVSKAJA, N. D. (1957): Three new II Problems of oil and gas content beds fern genera from the Lower Cretaceous in Arctica. Bull. Inst. Arct. Ceol., Min. in the lower course of Lena. Sci. Rep., Ceol. & Protect. Undergr. Res., USSR. Inst. Arct. Ceol. Min. Ceol. USSR, Proc. vol. 128, p. 1-96, pis. 1-49. (in Russian). Palaeo11t. Biostratigr., vol. 3, p. 69-76, pis. Y ABE, H. (1903): Mesozoic plants from 1-2. (in Russian). Korea. journ. Call. Sci., Imp. Univ. -- (1966): Some early Cretaceous plants Tokyo, vol. 22, no. 8, p. 1-59, pis. 1-4. from the Zyrianka District (Lena Coal­ YOKOYA~IA, M. (1889): Jurassic plants from Basin). Ibid., vol. 15, p. 49-76, pis. 1-7. Kaga, Hida, and Echizen. Ibid., vol. 3, (in Russian). pt. 1, p. 1-66, pis. 1-14.

Akaiwa iJ.r-;'fi, Bettokuzure JJIj~

**::z ~ 7 :/l::'if!IiJ.r-;fiJl (E~&BJii:tlf.Hff)) 0)11i'!4W1l:E (jj1!!Jn): ~ ~1c:.¥IH!r (KI"IURA & SEKIDO, 1976b) Lt-:~~Ic:.1Jn;t -C, ~1?1c:.---::>~O)~1i.l~ jj1!!JQ~cJiiJi:Lt-:; Cleichenites nip­ ponensis, Coniopteris saportana, Adiantopteris sewardii, A. toyoraensis, Cladophlebis ex gr. williamsonii, Raphaelia diamensis, Dictyozamites cfr. obliquus, Nilssonia schmidtii, Butefia? sp., Cinkgoites paradiantoides, Arctobaiera? sp., Elatocladus sp. C U J: u~ sp. D, Protodammara sp. U J: (f Carpolithes sp. :. h -r:, 1976if.j;J ll1J1c:.vi~ I? h -C l ,t... iJ> "J t-:iJ.r-;fiJl U J: "(fFiiJ;f§~JlO)11i'!4W:tlfO)mJR~~(:!:.~ -;zHc:.if-:i" c U ~ c t... "J t:: 0 ~ ~ 1c:.'¥1i15 L t-: Adiantites Ill1. (GOEPPERT, 1836) Ic:.l~~? I) , *~i1li)( J: ~ Adiantopteris ~ (V ASSILEV5KAJA, 1968) ~ J'Ih' 7.< eeL t-: 0 "i t-: Clei­ chenites aff. porsildi Ic:.---::>l'-Cfi, 4-JiNH'1!!Il*iJ~t-\tl?h, :'hc~~0)1!!Il*c~il'f.ii'!IH:'lt 'R~M L td6*, :. h I? fi, Cleichenites porsildii c !KJJiJ"C'~t... l':' c iJ~ ~Jj~ L t-:O)"C'::: ::: IC!I}F.cJlll(;L t-:o tJ.J::O):' -t:" Coniopteris saportana, Raphaelia diamensis, Dictyozamites cfr. obliquus, Nilssonia schmidt ii, Cinkgoites paradiantoides, Protodammara sp. t... 1:' fi, l3*iJ>l?li:/&fJJO)ffi!±l-r:.'l?00 :.hl?fH'fh{, VAKHRAMEEV 1c:.J: "J-C~Pl[\~:!l, -Cl' 0, :/:;1. 7 *,ciJ> I? ll1JWl B!!!!*,~Jc:.td-: {,';'-'" ~ 711i'!4WtmJl!!.!K~!\o/.J:tlfI:'fi ~b6b-C1}jjjjiB9;'d:fi,~"C' .'l?00 *N te ~ . I*l P fi3 IX Trans. Proc. Palaeont. Soc. Japan, N. S., No. 109, pp. 280-292, pI. 39, April, 30, 1978

687. FURTHER NOTES ON VASCOCERATID AMMONITES FROM HOKKAIDO (STUDIES OF THE CRETACEOUS AMMONITES FROM HOKKAIDO AND SAGHALIEN-XXXIII)

T A TSURO MATSUMOTO

c/o Department of Geology, Kyushu University, Fukuoka 812

and

KIKUWO MURAMOTO

Mikasa City Museum, Mikasa, Hokkaido 068-22

With Notes on the Early Turonian Palaeogeography

(Tatsuro MATSU~IOTO)

Abstract. Since previous descriptions (MATSUMOTO, 1973), more ammonites of the Vascoceratidae have been obtained from the Cretaceous of Hokkaido. They are described in this paper, in which a new species of Fagesia is included. In connexion with the distribution of the vascoceratids, notes are given on the Early Turonian palaeogeography.

stratigraphy and biogeography. Introduction This is a contribution to the interna­ One of us (MATSUMOTO, 1973) described tional project: Mid-Cretaceous Events. three species of the Vascoceratidae from The work has been financially supported the Turonian of Hokkaido, giving a notice by the Ministry of Education with the on their palaeobiogeographical implica­ Grant-in-aid No. 154280. tions. They / were Vascoceras sp. aff. V. Before going further we thank Dr. duratidi (THOMAS et PERON), Fagesia Hitomaro HONDA, Chief Geologist, Mr. thevestensis (PERON) and Fagesia sp. cf. Yasutaka FUJISHIMA, Geologist, and Mr. F. rudra (STOLICZKA). Since then more Tsutomu SA TO of the Hokkaido Colliery examples of the Vascoceratidae from & Steamship Co. Ltd., Yubari, who kindly Hokkaido have been assembled, aided provided us interesting specimens for our much by several friends of ours. In this study; Drs. Hiromichi HIRANO and Kazu­ and another paper (MATSUMOTO, 1977a) shige TANABE and Mr. Yuichiro MIYATA these species are described. We now (a student) of Kyushu University who have six species which afford us a valu­ cooperated with us in the field work and able basis to discuss the Turonian bio- provided the necessary specimens for this study. Dr. K. TANABE and Miss Mutsuko * Received August 26, 1977; read Oct. 4, HAYASHIDA have assisted us in preparing 1976 at Sapporo. the figures and the typescript. 280 687. Vascoceratid ammonites from Holclcaido 281 Systematic Descriptions [=Opiraushibets] ; ? GK. H 5858, from loco Y 6017 p5, in a small valley on the right Family Vascoceratidae SPATH, 1925 bank of the creek Taki-no-sawa, Oyubari Genus Vascoceras CHOFF AT, 1898 area, Hokkaido. All three collected by a field work team of Kyushu University Type-species:- Vascoceras gamai CHOF­ (H. H., K. T. & T. M.) FAT, 1898. Descripti ve remarks:-The three speci­ Remarks: - See MATSUMOTO 1973, p. mens of dissimilar size are all incom­ 27-28. pletely preserved. They are smooth ish and show the globose and considerably Vascoceras sp. aff. V. durandi involute shell-form, with inflated flanks (THOMAS et PERON) and a rather flattened venter. The su­ tures have massive broad saddles, an Text·fig. 1 opened general outline of L, and moder­ ately deep incisions at the base of L. 1973. Vascoceras sp. aft. V. durandi, MATSU. All of these characters suggest that the MOTO, Trans. Proc. Palaeont. Soc. Japan, specimens are probably referable to the [N. S.], no. 89, p. 29, pI. 8, fig. 1; text. fig. 1. species which was previously described under Vascoceras sp. aff. V. durandi Material :-GK. H 5856, from loco R 5235 (THOMAS et PERON, 1889) (see MA TSU­ pI, and GK. H 5857, from loco R 5207 p8, MOTO, 1973, p. 29, pI. 8, fig. 1 ; text-fig. 1). along the main stream on the River Obira Occurrence :-Although the three speci­ mens were obtained from fallen or floated calcareous nodules, the two localities -- ...... " , R5235p1 in the Obira area and Y6017p5 "­, in the Oyubari district probably indicate \ \ the derivation from a limited stratigra­ \ \ phic position in the lower part of the \ Lower Turonian. The previously report­ \ \ ed (MATSUMOTO, 1973) specimen of Vas­ \ lOmm I coceras aff. durandi came in situ from J I loco R2513a, but this locality is isolated _____ 1 a and its correlation with the better ex­ posed and more carefully measured sequence along the main stream of the River Obira has yet to be worked out. For the locations readers may refer to the route maps in TANABE et a!. (1977) and also HIRANO et a!. (1977).

Text.fig. 1. Vascoceras sp. aft. v. durandi (TI-IOYIAS et PERON). GK. H5856, from loco Genus Fagesia PERVINQUIERE, 1907 R5235p, lower part of unit Mj, Obira district. Diagrammatic whorl-section (a) and external Type-species: - Olcostephanus superstes suture (b) outside of the umbilical shoulder. KOSSMAT, 1897. (T. M. delin.) Remarks:-See MATSUMOTO, 1973, p. 32. 282 Tatsuro MATSUMOTO and Kikuwo MURAMOTO

Fagesia spheroidalis PERVINQUIERE spheroidalis. iV/aterial:-Yb 3001 of K. MURAMOTO'S PI. 39, Fig. 1; Text-fig. 2 Collection, fro:n a calcareolls nodule rest­ 1907. Fagesia superstes (KOSSMAT) var. sphe­ ing on the floor of the Taki-no-sawa, im­ roidalis PERVINQUIERE, Etudes de pale. mediately west of loco Y5102 of MA TSU­ ontologie tunisienne. 1. Cephalopodes MOTO and OKADA (1973), in the Oyubari des Terrains secondaires, p. 32,1, pI. 20, district of central Hakkaido. figs. 3, 4 and fig. A. Specific characters: - Shell large and 1965. Fagesia superstes var. spheroidalis COL­ cadicone, consisting of much depressed LIGNON, Atlas des Fossiles Caracte­ whorls which have a broadly arched venter ristiques de Madagascar, fasc. 12, p.46, pI. 395, fig. 1677. and much depressed section. Umbilicus moderately narrow, about one third of Lectotype :-Of the two illustrated syn­ the shell-diameter, deep, and surrounded types the larger one (PERVINQUIERE, 1907, by a nearly vertical umbilical wall and p. 324, fig. 122, pI. 20, fig. 4 and fig. A) a subangular shoulder. is designated here as the lectotype of F. Umbilical nodes thick and blunt, about

10mm J / / / ',: '\'.. f;

\ \ \ ,tv \. 5 / "'I u, '-" ' ,

a b ...... r;J;;} ( (! r'l'f 1I?tfq L~m it :, '.' "·

Text·fig. 2. Fagesia spheroidalis PERVINQUIERE. Yb 3001 of K. MURAMOTO Collection, from near loc. Y5102, Oyubari area. Diagrammatic sketch of frontal (a) and lateral (b) views, with a restored shell-form; external suture (c) at the middle growth-stage (whorl­ . height=43 mm). (T. M. delin.) 687. Vascoceratid ammonites from Hoklcaido 283

12 to 13 per whorl. They may be ed. As shown in the measurements be­ strengthened at the umbilical sh oulder low, it is characterized by its cadicone on the outer whorl. Radial ribs weak, general shell-form, much depressed whorl­ gently concave and numerous; 4 or 5 section (B/H=2.46), broadly arched ven­ ribs corresponding to a node, some ter, deep umbilicus showing a stepwise branched from the node and others in­ structure due to the combination of a serted. On the whorl of the late growth­ subangular umbilical shoulder and a high stage the ribs are much weakened or al­ and vertical umbilical wall, thick nodes most lost. at the umbilical shoulder numbering 12 Suture of Fagesia type, being similar or 13 per whorl, and weak ribs branched to that of F. superstes as illustrated by at the nodes and also inserted between KOSSMAT (1897, pI. 17 [6], fig. lc), hav­ them. The ornament becomes blunter ing deep E and L, tall saddles at E-L and as the whorl grows. The suture is fairly L-U2, narrow and long lobules and folioles. well exposed, showing the general Description of the Oyubari specimen:­ pattern of Fagesia (see Fig. 2c). L is This is still septate at its diameter of expanded by diverging branches. 163 mm, and no body-chamber is preserv-

Measurements (in mm):- Specimen Diameter Umbilicus Height Breadth B./H. Yb 3001 163 (1) 55 (0.34) 58 (0. 36) 145 (0. 89) 2.46 Lectotype 135 (1) 36 (0.27) 53 (0.39) 139 (1. 72) 2.62

Discussions:-The described specimen ter it is crater like. These characters from Hokkaido has essentially the same should be effective to the mode of move­ characters as the lectotype and other ex­ ment in the sea water. Moreover, the amples of Fagesia spheroidalis from Tuni­ former has more numerous and finer ribs sia and Madagascar (listed above). Al­ than the latter. L in the suture of the though it shows a somewhat broader former has larger and. cmore diverged umbilicus and a less depressed whorl, branches than that of the latter. these minor differences are regarded as Occurrence :-In Tunisia and Madagas­ variations within a species, as is some car this species is reported to occur in range in the number of tubercles (10-13 the Lower Turonian. The locality record per whorl). of the Oyubari specimen strongly sug­ Fagesia spheroidalis was established by gests the derivation from a comparatively PERVINQUIERE (1907, p. 324) as a variety upper part of the Lower Turonian sequ­ of F. superstes (KOSSMAT) (1897). This ence along the Taki-no-sawa. has been followed by COLLIGNON (1965, p. 46). We think it better to regard them as distinct species, because of the distinct Fagesia japonica sp. noV. morphological difference which would be PI. 39, Figs. 2, 3; Text-fig. 3 effective enough for giving rise to a dissimilar mode of life. F. spheroidalis Material :-Holotype, HCS. No.1, from has much broader whorls than F. sup­ a sandy calcareous nodule at loco H2074, erstes. In the former the umbilicus shows on the left bank of a creek called the a step-wise deepening, whilst in the lat- Nutapomanai, a tributary of the River 284 Tatsuro MATSUMOTO and Kiku'Wo MURAMOTO

Hobetsu, collected by Tsutomu SA TO Specific characters:-Shell large and (Sept. 1971). Paratype 1. GK. H5855 from globose in general aspect. consisting of the mudstone at loco R5231b, main stream fairly involute whorls. which have a steep. of the Obira [=Opiraushibets], found by almost vertical, high umbilical wall, sub­ Yuichiro MIYATA during the field work angular umbilical shoulders. gently con­ by a team of Kyushu University (K. T A­ vex, convergent flanks passing gradually NABE, H. HIRANO, Y. MIYATA and T. to a rounded venter, and accordingly a MA TSUMOTO, on Aug. 13, 1975). Para­ semi-circular to semi-elliptical cross-sec­ type 2, Ob1005 of K. MURAMOTO Collec­ tion, with the maximum breadth between tion (Mikasa City Museum), from a cal­ the umbilical shoulders. Umbilicus fairly careous nodule at R4601, an intensely narrow and deep, showing a stepwise meandering point of the creek of Naka­ structure by the combination of vertical kinembetsu, a tributary of the Obira, at umbilical walls and subangular shoulders. a point 250 m NWW from the conference Inner whorl has small tubercles at the with a small tributary called the 82 Rin­ umbilical shoulder, 10 or so per whorl, and pan-no-sawa, collected by K. MURAMOTO numerous, weak ribs, which are flex ira­ (Sept. 16, 1973). diate, diverged or intercalated on the

J c lOmm

Text·fig. 3. Fagesiajaponica MATSU~JOTO et MURAMOTO, sp. nov. Holotype, HCS. No.1 (T. SATO CoIl.), from loco H2074p, Hobetsu district. Diagrammatic sketches of lateral (a) and back (b) views· and a whorl·section (c) ; external suture (d) at S. (T. M. delil1.) 687. Vascoceratid ammonites from Hokkaido 285 flanks and curved moderately forward on is somewhat larger than the holotype, the venter, where faint constriction like, but its outer half whorl is poorly pre­ slightly deeper inters paces are periodically served and an apparently subtrigonal discernible. Outer whorl nearly smooth, whorl-section of the preserved last part but with distant, blunt umbilical nodes. may be due to the secondary deformation. Suture essentially similar to that of Paratype no. 2 is much larger and re­ Fagesia superstes as illustrated by Kos­ garded as representing the adult stage. SMAT (1897, pI. 17 [6], fig. lc), but has a Its last septum is at about 210 mm in dia­ somewhat broader stem of L and a meter but its body-chamber is almost lost. broader saddle between E and L. Its outer whorl tends to be subtrigonal Remarks:-Holotype is immature but in . cross-section and its height seems to well preserved. Paratype no. 1 (D.=87.5) be reducing.

Measurements (in mm):- Specimen Diameter Umbilicus Height Breadth B./H. HCS. No.1 57.0 (1) 10.5 (0.18) 29.0 (0.49) 42.4 (0.72) 1. 46 GK. H5855 54.5 (1) 10. 1 (0. 19) 27.5 (0.50) 20 x 2 (0.7) 1.4 Db 1005 207.0 (1) 41. 5 (0.20) 41. 5 (0.44) 65 x 2 (0.6) 1.4

Discussion:-This species is characteriz­ only) and probably also Hokkaido (MATSU­ ed by its peculiar shell-form which recalls MOTO, 1973, p. 34, text-fig. 3), in its glo­ us certain species of Vascoceras [e. g. V. bose aspect, narrow and deep umbilicus polygonum BARBER (1957, p. 17, pI. 5, fig. and weak ornament. It is, however, dis­ 2; pI. 29, figs. 1-3)], but its suture is dis­ tinguished from that species in its some­ tinctly of Fagesia type, characterized by what higher whorl with a distinctly nar­ tall saddles deeply incised by narrow rower, moderately instead of broadly lobules. rounded venter, and somewhat broader In the same respect it resembles Fagesia stem of L. involuta BARBER (1957, p. 27, pI. 9, fig. 3 ; Some of the variable forms of Fagesia pI. 29, figs. 6-7), from the Lower Turonian lenticu~aris FREUND and RAAB (1969, p. of north-eastern Nigeria, which was re­ 36-42, with subspecific names which we garded by BARBER as somewhat inter­ regard as untenable because of their oc­ mediate between Vascoceras and Fagesia. currence in the same zone of the same That Nigerian species has, however, more area), from Zone 6 of the Lower Turonian distinctly sub trigonal whorl-section and of Israel, may be similar to F. japonica less numerous,· much coarser umbilical in shell-form but has distinctly coarser tubercles. ribs on its inner whorl. F. jajJonica is fairly close to Fagesia Occur-renee :-See ·the locality records rudra (STOLICZKA, 1865), a more wide" described under the heading Material. spre::).d species known from the Lower The sandy layer of the type locality in Turonian of southern India (STOLICZKA, the sequence of the Nutapomanai is cer­ 1865, p. 122, pI. 60; KOSSMA T, 1897, p. 29 tainly . lower than but not much apart [136J), Tunisia (PERVINQUIERE, 1907, p .. from. the prolific Zone of Inoceramus 322), Madagascar (COLLIGNON, 1965, p. 48, hobetsensis and accordingly it is regarded pI. 396, fig. 1678A; p. 397, fig. 1678-B), as representing a comparatively upper Spain (WIEDMANN, 1960, p. 720, listed part of the Lower Turonian in the Hobe- 286 Tatsnro MATSUMOTO and Kiknwo MURAMOTO tsu area. The paratype no. 1 is precisely there are now six species of the Vasco­ allocated at a horizon immediately below ceratidae from the Lower Turonian of the key member of tuff and tuffite in the Hokkaido. One of them is Vascoceras aff. middle of Member Mj of TANAKA (1963). durandi, for which four examples are at This is in the middle part of the Lower our disposal and three of them came Turonian sequence in the Obira area, from a limited part of the Obira area. since Vascoceras aff. durandi came from There are four species of Fagesia, of the lower part of the sequence along the which one is, so far, endemic of Japan. same route. The paratype nO. 2 from This is represented at present by at least the same Obira area is a somewhat trans­ three specimens. ported calcareous nodule derived probably The occurrence frequency of the above from somewhere within Member Mj. It species in Hokkaido is approximately the should be noted that Neoptychites cepha­ same as that of certain species of the lotus (COURTILLER) was found in another Acanthoceratidae or Collignoniceratidae nodule of the same spot (see MATSUMOTO, there. 1977a). As is described in another paper (MA­ TSUMOTO, 1977a) Neoptychites cephalotus (COURTILLER) has recently been found Appendix from the Obira area of Hokkaido. It is represented by an adult specimen in Notes on the Early Turonian which the body-chamber is nearly com­ Palaeogeography pletely preserved. (Tatsuro MATSUMOTO) The above facts altogether suggest that at least several species of the Vascocera­ In connexion with the distributional tidae lived in the Turonian Japanese pro­ records of the vascoceratid ammonites, I vince. Postmortem drifting of shells for should like to give further remarks on a long distance from somewhere in epi­ the palaeobiogeographic aspects of the continental areas around the Tethys could Early Turonian time. be considered as another alternative, but En vironmental conditions;-Ammonites this seems to be less probable for the belonging to the Vascoceratidae normally increasing records of the vascoceratids occur abundantly in the sediments of from our province. The relative scarcity shallow epicontinental seas. They are of the fossils is probably due to that the mostly characterized by a globose or main part of the sedimentary basin of roundish shell-form, smooth ish surface Hokkaido (i. e. the so-called Yezo geo­ with reduced ornaments and more or less syncline) was more or less deeper and pseudoceratitic sutures. Presumably these off-shore than the original habitats and morphological characters of the shell may that the optimum shallower parts at the have been favourable for their living in margin of the basin may have been nar­ very shallow, sometimes wavy seas. row because of the tectonic instability in In the Cretaceous rocks of Hokkaido, East Asia. Species of Fagesia have vascoceratid ammonites are indeed rare more complex sutures than other genera in comparison with desmoceratids, tetra­ of the Vascoceratidae and they may gonitids and certain groups of hetero­ have an ability to go down to some morpha, but they do occur. Aside from deeper part of the sea. This may be two species of Hourcquia of later ages, consistent with the fact that fossils of 687. Vascoceratid ammonites f1·om Hokkaido 287 Fagesia have been found more commonly rather infrequent, I hope that an increas­ in Hokkaido than other genera of the ing number of records of the vascoceratid family. ammonites from Hokkaido may serve for Correlation: - Vascoceras and F agesia the correlation of the ammonoid faunas occur in the Lower Turonian of various of the Tethys region with those of the region of the world and they have been Pacific. found also from the Lower Turonian Palaeogeographic aspects:-Vascoceratid equivalent in Hokkaido. Inoceramus (My­ ammonites are distributed mainly in the tiloides) labiatus (SCHLOTHEIM) (s. 1.) oc­ Turonian 'epicontinental sea areas facing curs in the same unit, if not in the same the Tethys Sea and its extensions. On bed (MATSUMOTO and NODA, 1975). the previous occasion (MATSUMOTO, 1973) If we examine more carefully the strati­ a Turonian palaeobiogeographic map was graphic sequences, we notice that fossils presented, showing the distribution of of Fagesia occur in (or presumed to have selected ammonite genera. That was derived from) comparatively upper to drawn on a world map of the present middle parts of the probable correlative land and sea configuration. of Lower Turonian in Hokkaido. For In this paper I dare to plot the distri­ instance, in the sequence exposed along bution data of Fagesia on a tentatively the main stream of the Obira, Fagesia reconstructed palaeogeographic map (Fig. japonica is found at a horizon about 50 m 4). For the reconstruction I depend es­ above that of Vascoceras aff. durandi, al­ sentially on DIETZ and HOLDEN (1976) though there is still a doubt about the rather than SMITH et al. (1973), because adequate correlation of the bed of the the former seems to be preferable to ex­ latter species exposed at loco R2513a on plain the faunal migration. For the early the bank of the tributary Okufutamata Turonian palaeogeography it is necessary with that of the main stream. It should to modify reasonably the two maps (at also be noted that a larger example of about the beginning and the end of the F. japonica was collected from the Naka­ Cretaceous period) of DIETZ and HOLDEN. kinembetsu, another tributary of the Obi­ One of the questions in the reconstruc­ ra, from the same spot as a specimen of tion is how broad or narrow was the Neoptychites cephalotus. Although they Tethys Sea in the early Turonian time. were obtained in transported or washed Another question is how broad or narrow out nodules, they have the same lithologic was the opening North and South Atlantic character that suggests the derivation Oceans. The answers would affect the from the same unit Mj (see MATSUMOTO, interpretation of faunal similarity and 1977a). dissimilarity between both sides of the The above facts are generally in har­ deep sea-ways. mony with the successions in the Tethys As the Turonian is at the middle of region, as revealed by WIEDMANN (1960, the long period of geomagnetic quietness 1964) in Spain and by FREUND and RAAB 0. e. a continuously normal geomagnetic (1969) in Israel. polarity) (LARSON and HELSLEY, 1975), it As has been pointed out by HANCOCK is fairly difficult to allocate precisely the et al. (1977), the adequate scheme of the subcontinents of India and Madagascar Turonian biostratigraphic subdivision has on the map. The result would also affect not yet been established even in western the interpretation of Turonian faunal Europe. Although the occurrence is affinities between Japan and these places. 288 TatSt£1'O MATSUMOTO and Kikt£WO lV!URAMOTO

Text-fig. 4. Map showing the distribution of selected genera of the Vascoceratidae: Vascoceras and/or Plesiovascoceras with solid reversed triangle; Paravascoceras and Para­ mammites with solid circle; Fagesia with empty triangle. Tentative reconstruction of Eady Turonian palaeogeography modified from DIETZ and HOLDE=" (1970). (T. M. delin.)

In view of these difficulties, the map As to the South Atlantic the present in this paper is quite tentative, but I have reconstruction is much broader than that shown it towards further refinement in of REYMENT and T AIT (1972). In view the future. of the hypothesis of a world-wide increase Some information of regional geology in spreading rates during the period of should be taken into consideration for the 110 to 85 m. y. ago (LARSEN and PITMAN questions. For instance, the pink pelagic III, 1972), it is strange to see little open­ limestone of the Scaglia rossa of the Ita­ ing of the South Atlantic from Middle lian Appenines record the existence of Albian to late Early Turonian in their deep sea in Late Cretaceous times up to map. Moreover, the recent information middle Eocene (ALVRAFEZ eta!., 1977). of DSDP Leg 40 tells us that the drilling The Aruma pelagic shale, comprising the cores at site 364 contain cosmopolitan Hawasina facies, of the Oman mountains Albian ammonites (Mortoniceras, Puzosia record the existence of eugosynclinal deep (?), Tetragonites (?) etc.) and Inoceramus sea in Late Santonian-Early Maestrichtian ct. anglicus WOODS (see MATSUMOTO, times (WILSON, 1969). In Early Turonian, 1977b, in press) and that the Albian and therefore, the oceanic part of the Tethys Upper Cretaceous sediments are micritic must have existed with a certain breadth. and pelagic. These suggest the exist- 687. Vascoceratid ammonites 11'0111 Hokkaido 289 ence of a free sea-way rather than a the intimate faunal affinity of this region closed one in Late Cretaceous times. with the northern Andean province can The distribution pattern of the vasco­ be explained in a similar way or other­ cera tid fauna in contrast to Collignonieeras wise is a problem to be worked out. (5) (Sel!c),noeeras) assemblage can be explain­ The distinct fauna of Morocco (COLLIG­ ed, even if the South Atlantic was opened NON, 1966) may be ascribed to the with a moderate breadth. I should con­ welling up of the cooler water mass of sider the two kinds of oceanic currents the North Atlantic (EINSELE and WIED­ or water masses in the oceanic area and MAl\N, 1975). (6) There was naturally factors of optimum depth in accordance a faunal affinity between southwestern with the history of transgression-regres­ Europe and the Gulf Coast plus the sion in the epicontinental area. southern Western Interior of North Considering the effect of subsequent America. (7) The vascoceratid fauna of erosion, the shelf sea is drawn to be the \Vestern Interior had some, if not somewhat broader than the outcropping remarkable, peculiarity (e. g. prevalence area of the Lower Turonian, as in my of the subgenus Greenhornoeeras COBBAN previous map. Taking the Turonion re­ and SCOTT, 1972) as that of central Asia gression from the Arabian shelf (POWERS had another peculiarity. (8) Fagesia and et aI., 1966; AL NAQUIB, 1967) into con­ N eoptyehites (see also another map in sideration, the epicontinental sea is revised MA TSUMOTO, 1977a, fig. 2). of the late to be reduced, although how narrow was Early Turonian, are more widespread the shelf sea in the Early Turonian is than other vascoceratids. This is pro­ not precisely recorded in the available bably due to more active ability of their references. The want of information in locomotion and also to expanded marine southern Asia is the same as in the pre­ transgression in many regions. (9) There vious ~ase. are doubtful records of Fagesia from New Although I plot the distribution data of Caledonia (KILIAN, 1910) and California selected five genera, the present map (Fig. (represented by F. siskiyouensis ANDER­ 4) is fairly good to understand or inter­ SON, 1931), for which no suture has been pret the following palaeobiogeographic described and the homoeomorphy with features: (1) In general the vascoceratids certain Lewesiceras could be considered. were distributed in the Early Turonian Aside from the above doubtful one, there epicontinental areas surrounding the is in California a species of Plesiovas­ Tethys sea and its extensions. (2) Vas­ coeeras which is somewhat allied to the coeeras and Plesiovaseoeeras prevailed in Western Interior species (see MATSUMOTO, the northern shelf sea, whereas Para­ 1959, p. 102). (10) It is considered that vascoceras, Gombeoceras and Paramam­ certain species of the Vascoceratidae lived llzites did so in the southern shelf sea, as in the Japanese province (see p. 286). FREUND and RAAB (1969) pointed out. Hokkaido is much separated from any of (3) This faunal distinction was not strict the known distributional areas of the and the two faunal elements intermingled vascoceratids. To make clear the route to some extent (MATSUMOTO, 1973). (4) of migration the information from south­ The intimate faunal relation between ern Asia is especially wanted. West Africa and East Brazil may have been due to the southern equatorial cur­ rents in the South Atlantic Sea. Whether 290 Tatsuro MATSUMOTO and Kikuwo MURAMOTO Geol. Tananarive. References Cited -- (1966): Les cephalopodes cretaces du bassin cotier de Tarfaya. Notes et Mhn. (References of the basic data for the distri­ Servo Ceol. Maroc, no. 175, 148pp, incl. bution map of the vascoceratids were indi­ 35pls. cated in MATSUMOTO, 1973 and not re­ DIETZ, R. S. and HOLDEN, J. C. (1970): Recon­ peated here, but for the addition of FRI­ struction of Pangaea: Break up and dis­ TZSCHE, 1924.) persion of continents, Permian to Recent. Jour. Ceophys. Res., vol. 75, p. 4939-4958. AL NAQUIB, K. M. (1967): Geology of the EINSELE, G. and WIED'I;IANN, J. (1975) : Faunal Arabian Peninsula. Southwestern Iraq. and sedimentological evidence for upwell­ U. S. Ceol. Surv. Prof. Paper 560-G, p. ing in the Upper Cretaceous coastal basin 1-5c1, pIs. 1-4. of Tarfaya, Morocco. I Xth Intern. ALVAREZ, W., ARTHUR, M. A., FISCHER, A.G., Congr. Sedimentology, Nice, 1975, Theme LOWRIE, W., NAPOLEON, G., SILVA, 1. P. 1, p. 67-74. and ROGGENTHEN, W. M. (1977): Upper FREUND, R. and RAAB, M. (1969) : Lower Turo­ Cretaceous-Paleocene magnetic stratigra­ nian ammonites from Israel. Spec. Pap. phy at Gabbio, Italy. V. Type section for Palaeont., no. 4, p. 1-83, pIs. 1-10. the Late Cretaceous-Paleocene geomagnet­ FRITZSCHE, C. H. (1924): Neue Kreidefaunen ic reversal time scale. Ceol. Soc. Amer. aus Stidamerika (Chile, Bolivia, Peru, Bull., vol. 88, p. 383-389. Columbia). Neues Jahrb. Min. Ceo!. Palae­ A:"DERSO:", F. M. (1931): The genus Fagesia ont., Beil. Bd. 50, p. 1-56,313-334, pis. 1-4. in the Upper Cretaceous of the Pacific HANCOCK, ]. M., KENNEDY, W. J. and WRIGHT, coast. Jour. Paleont., vol. 5, no. 2, p. 121- C. W. (1977): Towards a correlation of 126, pIs. 15-17. the Turonian sequences of Japan with BARBER, W. (1957) : Lower Turonian ammoni­ those of north-west Europe. Palaeont. tes from north-eastern Nigeria. Ceol. Soc. Japan, Spec. Pap., no. 21, p. 151-168. Surv. Nigeria, BUll. no. 26, p. 1-86, pIs. HIRANO, H., MATSUMOTO, T. and TANABE, 1-34. K. (1977) : Mid-Cretaceous biostratigraphic COBBAN, W. A. and SCOTT, G. (1972): Strati­ succession in the Oyubari area, central graphy and ammonite fauna of the Gran­ Hokkaido. Ibid., no. 21, p. 1-10. eros Shale and Greenhorn Limestone near KILIAN, W. (1910) : Sur la presence de Fagesia Pueblo, Colorado. U. S. Ceol. Surv. Prof. en N ouvelle-Caledonie. Bull. Soc. Ceol. Paper, 645, p. 1-108, pis. 1-39. France, ser. 4, vol. 10, p. 29. COLLIGNON, Maurice (1965): Atlas des Fossiles KOSSMAT, Franz (1897): Untersuchungen tiber Caracteristique de Madagascar (Ammoni­ die stidindische Kreideformation (Zweiter tes). fasc. 12, p. 1-82, pis. 376-.113, Servo Theil). Beilr. Paliionl. Oesterr.- U gnarns

Explanation of Plate 39

Fig. 1. Fagesia spheroidalis PERVINQUIERE· ...... Page 282 Yb 3001 of K. MURAMOTO'S Collection, from Taki-no.sawa, Oyubari area, central Hok­ kaido. Lateral (a) and frontal (b) views, xO.5 Figs. 2, 3. Fagesia japonica sp. nov.··················· ...... · ...... Page 283 2, Obl005 of K. MURAMOTO'S Collection, from loc. R4601p, Naka-kinembetsu in the Obira area, northwestern Hokkaido. Lateral (a) and frontal (b) views of a larger paratype, xO.3. 3, Holotype, HCS. No.1, from loco H2074, Nutapomanai, in the Hobetsu area, central Hokkaido. Lateral (a) and back (b) views, xl. Kyushu University [K. TANABE] photos, without whitening.

687. Vascocemtid ammonites from Hokkaido 291

u. d. Orients, vol. 11, p. 1-46 [108-153J, POWERS, R. W., RA;-"IRIEZ, L. F., REDMOND, pIs. 1-8 [12-19J. C. D. and ELBERG, Jr. E. L. (1966) : Geology LARSON, R. L. and HELSLEY, C. E. (1975) : Meso­ of the Arabian Peninsula. Sedimentary zoic reversal sequence. Rev. Geophys. & geology of Saudi Arabia. U. S. Geol. Surv. SPace Phys., vol. 13, p. 174-209. Prof. Paper 560·D, p. 1-147, pis. 1-10. LARSON, R. L. and PIT;-"IAN III, W. C. (1972): REYMENT, R. A. and TAIT, E. A. (1972): Bio­ World-wide correlation of Mesozoic mag­ stratigraphic dating of the early history netic anomalies and its implication. Geol. of the South Atlantic Ocean. Phil. Trans. Soc. Amer. Bull., vol. 83, p. 3645-3662. Roy. Soc. London, ser, B. vol. 264, p. 55- MATSUMOTO, Tatsuro (1959): Upper Creta­ 95, pis. 3-5. ceous ammonites of California. Part. II. SMITH, A. G., BRIDEN, ]. C. and DRE\\'RY, G. E. Mem. Fac. Sci., Kyushu Univ., ser. D. (1973): Phanerozoic world maps. Spec. Special vol. 1, p. 1-172, pis. 1-41. Pap. Palaeont., no. 12, pp. 1-42. -- (1973): Vascoceratid ammonites from STOLlCZKA Ferdinand (1863-66) : Ammonitidae, the Turonian of Hokkaido. Trans. Proc. with revision of the Nautilidae, etc. In Palaeont. Soc. Japan, N. S. no. 89, p. 27- BLANFORD, M. F. and STOLlCZKA, F., 1861- 41, pI. 8. 66. The fossil Cephalopoda of the Creta­ -- (1977 a): A record of Neoptychites from .;eous rocks of southern India. Mem. Geol. the Cretaceous of Hokkaido. Recent Res. Surv. India, Palaeon!. Indica, vol. 1, p. in Geol., Delhi, vol. 4, p. 196-207. 41-216, pis. 26-94. -- (1977 b, in press): Notes on Inoceramus, TANABE, K., MATSUMOTO, T., HIRANO, H. Mesozoic bivalves, from the southeastern and MIY ATA, Y. (1977): Stratigraphy of Atlantic, DSDP sites 361 and 364, Leg 40. the Upper Cretaceous deposits in the Obira Initial Rept. Deep Sea Drilling Project, vol. area, northwestern Hokkaido. Sci. Rept. 40. Dept. Geol., Kyushu Univ., vol. 12, no. 3, MATSU~IOTO, Tatsuro and NODA, Masayuki p. 181-202 (in Japanse with Engl. ab­ (1975) : Notes on Inoceramus labiatus (Cre. stract). taceous Bivalvia) from Hokkaido Trans. TANAKA, Keisaku (1963): A study of the Proc. Palaeon!. Soc. Japan, N.S., no. 100, Cretaceous sedimentation in Hokkaido, Ja­ p. 188-208, pI. 18. pan. Geol. Surv. Japan, Rept. no. 197, MATSUMOTO, Tatsuro and OKADA, Hakuyu 119pp. (1973): Saku Formation of the Yezo geo­ WIEDMANN, Jost (1960): Le cretace superieur syncline. Sci. Rept. Dept. Geol., Kyushu de l'Espagne et du Portugal et s~s cepha­ Univ., vol. 11, no. 2, p. 275-309 (in Jap­ lopodes. 84° Congres Soc. sat'anles, 1959, anese with Engl. abstract). Dijon, p. 706-764. PERON, Alphonse (1889-90): Description des -- (1964) : Le cretace superieur de I'Espagne mollusques fossiles des terrains cretace et du Portugal et ses cephalopodes. de la region des Hautes Plateaux de la Esludios Geolog icos, Insl. Lucas M allada, Tunisie. Recueillis en 1885 et 1886 par M. C.S.1.C. (Espana), vol. 20, p. 107-148. Phillipe Thomas. Exploration scientifique WILSON, H. H. (1969): Late Cretaceous eugeo· de la Tunisie, 405p., 35pls., Paris. synclinal sedimentation, gravity tectonics PERVINQCIERE, L. (1907) : Etudes de paleonto­ and ophiolite emplacement in Oman moun­ logie tunisienne, 1. Cephalopodes des ter­ tains, southeast Arabia. Amer. Assoc. rains secondaires. Carte geol. Tunisie, Petrol. Geol., Bull., vol. 53, p. 626-671. 483pp., 27 pis.

82 Rinpan-no-sawa. (82 1*.FlEJ»)R) , Hobetsu ('f!!.\lJlj) , Naka-kinembetsu (q:r*'c;ftlJU), Nuta­ pomanai (;;<;ll ;i'h' j-·n, Obira (/j>3F) , [=Opiraushibets (;t 1::,0'7 :/'''' '/)], Okufutamata (~=m,t), Oyubari (:;k ,9,*), Taki·no·sawa (itO))R) 292 Tatsu1'O MATSUMOTO and Kiku~vo MURAMOTO

~tiiIJ)llUlif /~ 7-, ::z -t: '7 7-, H 7 :/.'f:- -r -{ r 0) ~JC$R: ~tiiIJ:@:~ 0) /~ 7-, ::z -t: '7 7-, f~r 7 :/.'f:- -r -{ r ~ 1973 1pK.$R1!i- 1...- -C tJ*, 1i'lJ~;I·O){t=5iJ; ~ G ~::.:!ire"i ":>1-:'0 ;:;h. G ~~:gln."" *iiwo;t"C'ft, Vas­ cocems aff. durandi (THOl\'IAS et PERON) (1ltr@lO) C Fi'J-:ft0)JJi'tjm~;f4), Fagesia sphe­ roidalis PERVINQUIERE, Fagesia japonica sp. nov. 0) 3 *,!fi~8Glf~1...- t-:.o ;: o)1'J.iJ' Neopl),­

chiles cephalotus (COURTILLER) "{., jo 0 iJ;;m*iJ;5Jljiiwo;t~qc.]I~-t 0 0 10 * ~ Jl!r> • H*{~Pd:f~

I;H~: 7- "" - P :=. 7 :/:fJJWJO)t!:llliJill: l:8C.0)~:ftft \, 'fn"{., Blfu-*7- "" - P :=. 7 :/rffll-z.4'ii' f3 ---j,t 0 0 Fagesia ft..:t O)J:j:IO) ftilr1f:r':1l:ffl\iJ,J:j:IfflW:.$ <~-t 0 0 /~ 7-, ::z -t: '7 7-,~;1·0) 7 :/.'f:- -r-{ r ft, ~1l~j0)7-7-7-,liIJ C ..:to)~:lHqfii Udli;#fj:[j!:HJlIl~::.±: C. 1...- -C 7J"1j1-t 0 iJ" ~tfl§:;t(¥f,pO)~tw

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PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY OF JAPAN

O~106-\} . ~~1iC.O)~:lJn. (4'If,\]1j~~J 3JZJgl.~, 1:i~ ~, ~JJ1Ul;:'=', ~~01JJ3, *~,,!,,~ (5 i'l) 01978i'f 1 J:j19S O)i1'-p.~~~~;::;t.o~'-C'ffiJ~~~O)r!t1!iIJO)~f~ c ~~O)~:lJnilti~!E~JLf,:. (~iit) i~r.. ~-!ij (IB~~), (il;~) 'N1H111!E (~~U~15~f;::.l: I) ~:lJn) O~~~~~~.O)~.~~~O)*.~~~fi~hh~M*, *i'f~O)~.~.W.~il;.O)~iI •••~ =·~ffi.±(~~~ff), m~R~'~*W~(~~~ff) ck~~. O~iW~~~~jJ:re~ht.:~~O)ilJMtit(xO)lili I) ~if> 7.> (~ftnwo. (A~~J !&!f /M!, )111:) ~-, ~ffi$'Rj, f:j: '~11', IOOlffim'.'1:, =*~=., 1fiJtt~1l!, j\1ij:m :,!:, iiFt0 ~P#, !fj:1j*,*, m~~:t, ~I!ifi~p#, ~*:f:~, i§lR. 93 (14i'l) (i!!il;~J lJIfffilnt;JtI~K. K, 4'7 :/1:iilllK. K, (• .Il1Jf'<. Hi:) ; J'tfj: R, 'Hi~~, ~ * .~, tj. !EJ!{I:!!., j\1ij!f ~, ~ M3JZ (-iflili~. 6 i'l) (jj1i*~J ••-U~, '.I:IIl:;lH,JjE, 4-!fPHlL 1'-F8a~ (4 i'l) (4'If,\]1j~~t;::m-lt~~ht.:~.J T.ff!\;~, iltrffif*~, *~'*jt,fJlII, f'l,i1l;~., i'lljj(t!}J:k, i§ffi.'1:AA, !f ffi~Z, ~~~~, 1fili!t1f=., *Di'ffiIE, f~ttaB5[,., 3JZ -5[,., im:j?Jm~, 1111:) ¥.!fZ (14i'l) (i'lI'~.t;::m-lt~~:ht.:~.J i~!f m', ~ffi~*, If[ri3~IF.¥~, j\1ij*~=. (415) .:to)M*, *f'<~~ ~-iflili~.n1i'l, 4'If~il;.1~i'l, ~~~.~i'l, i'l.~.8i'l, • .Il1J~~8~c~~~. O*~4'If,\]1j-\}~21-\} c L -Cf'l*~a~ogv:til'O) "Mid-Cretaceous events, Hokkaido Symposium, 1976" ilt flJfi ~ht,·.• "£ t.:, ~22-\} "Bibliography of Paleontology in Japan, 1961-1975" iI'itIfIjO)'f!E~ if> 7.> c i7)¥li15-tMJ: ~:ht.:. 01978i'fJ.t~~~OO)c.it, WI:) jt,fZogO) "Taxonomic studies on some fossil and recent Japanese Balanoidea" (¥li15-. iiG*107-\}, 108%) t;::tl'ilJ-~ht.:. . 01978i'fJ.t~*~JHb~it, j~r.. 9-!ijog ('*' . ii'!t f\:M¥J11:1:i 0)7iJf:1E) c::kffi IE)iog ('¥:kTlf1:iJY(!5 0) !E;f§ 0) 7iJf :1E) 1;::tl'ilJ-~ht.:.

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-gil Mt1::.' A r :/::1 7 *O)~fl::;o· ...... g§;fj lIB· g§;fjI!JFf- -1 :/ r·~M7K*0)~iIii~0)~ji[7Hjlt:.'?\"-C·············""""""" ·~IEJllr.- .!MJ;fj ~. 1JniiUit!!fl A few species of Hystrichokolpoma (Dinophyceae) from the Pleistocene sediment in Okinawa Jima ...... MATSUOKA, K. fjg~~~i*I:l:~tt~tJe!G-O)~{I::;o~(ft~EB~W'" ·iitill~1IB . 'NR ~. *" ;a-. *~Ii£5(fl'!~' iii JlIj!fE iM5iijlO)tt~jli**~~t:.'?\"-C············· ...... ,...... jliijlifji •• 'j'JR ~ ~ti1a~O)tt~~~f:' ,?\,'-C ...... "j' 7'R ~ Fossil Cervidae from Taiwan····································· ·OTUKA, H. and SHIKAMA, T. On some new materials of Gomphotherium annectens (MATUMOTO) from the Miocene Mizunami Group····················································································· ...... KAJ-IEI, T., Okazaki, Y. NONOGAKI, I., and Paleontology Club, Aichi Gakuin Univ. On Hipparion fauna of the Marageh district, North-West Iran························· ...... KAMEl, T., ISHIDA, S. and NAKAYA, H. Eocene land turtle discovered from Yubari city, Hokkaido ...... ·OKAZAKI, Y. New species of trionychid turtle from the Pliocene Age Group··················· ·OKAZAKI, Y. !G-;P9jHt!G-;oW(!G-*t:.AMEBm~~jl1pj<-t 7.> ...... ·!MJ;fj:/ltzl!tJ ~tM~~!Ji.~1.J>I?Je~(HttdxliX.'F,{I::;ot:.'?\"-C··············· .. ········· ...... :/It 1ElJ:- Bolivina robusta BRADY t:.~I?;hol'&O)MtmEB*t!&t:.'?\,'-C ...... ·~t.m. ~ mJII:Itl!.1.n:.~I?;hom~=:*c . ~gg*c~w.#JlIO)f1.JbfM:~:}L.'F,~O)1C~············· ·~*JlT . ± ~- !MJilI9~*H;oW(!G-t:.'@:-tO;o~*C0)7;;( ~ :rM .. · ...... ·ft;: IE ~ fjf ~J!t[!JjHi!ffmf!l!!MJIHT1.J>I?Je~ l...t.: Triticites {I::;o~t:.'?\"-C ...... f& iii j;JJ iJIJ; Paleontological study on the Copacabana Group at Hill of Jacha Khatawi in Yaurichambi area, Bolivia, South America, Part 1. Fusulinids········· 'YAl\IAGIWA, N. and URDININAE, M. R. Biostratigraphical zonation and Fusuline fauna of the Khao Khao section, Sara Buri, Central Thailand················································· ·TORIYAMA, R. and KANMARA, K. Cyclina sinensis O)?E9I.~ffiO)1t'l-ij--1 ;;(7f;(jlc-tO)MIll1:~~ ...... ·r ill IE- H1V~.MO)?E9I.-ij--1 ;;(7f;(jlmlll1:t:,~x.oP1~l:i-v r:IJ ~ O)-ij-.-( ;;(~tRM:tU: OllI;~l''''''''''''''r ill IE- Umboniulll miyagiense NOMURA and ONISI, 1940 t:.'?\',-C ...... "'j' 1R ~ 1:. *mtltO) Geloina ~~t:.'?\"-C ...... !M!JII i.$::: . g§JII !JJ g§mB*1:i!Ill~r~*t:'~I?;ho Inoceramus (Cataceramus) ex gr. balticus O)Mtm1Cfl::· .... ·ff IE Jl z *C~~~mi!llO)~=:*C9I.M{I::1j············· ...... ···~IE~-l'!~· ~iii~l'!p Occurrence of the Wuchiapingian (Early Lopingian) bivalves from the Nesen Formation in the central Alborz Range, Iran················································· ·NAKAZAWA, K. Shallow sea molluscan fauna in the northern border of the Shimanto Terrain, Kii Peninsula, West Japan··································· ·NAKAZAWA, K., KUMON, F. and KIMURA, K. Rates and pattern of size change in evolution ...... HAYAMI, I. A systematic survey of the Paleozoic and Mesozoic Gastropoda from Japan··· ...... HAYAMI, I. and KASE, T. =- "" - :IJ v r =- 7fJili(l\7'!-~t:.;t.;\-t 0**""':J * ry .l..:!l'-( O)ffIi~ ...... "~IE~± . =:1: jjt Biometric characteristics of Nautilus macromphalus.· ...... · ...... HIRANO, H. and OBATA, I. Some early Permian ammonoids from the Taishaku district, Hiroshima Prefecture, Japan····· ...... NISIIIDA, T., HAMADA, T. and NISHIKAWA, I. Upper Triassic ammonoids from Eastern Timor········· ...... ·BANDO, Y. ffJ'.l!Tltri¥:=:ii:*c7 :/"E':r-1 r "Ptychites" t:.'?\',-C ...... ;0 ~ ~ Mammites and allied ammonites from the Cretaceous of Hokkaido and Saghalien ...... 295

••...... •..••.••...... MATSU~\'IOTO, T., KA\\-ASI-IITA, Y. and FUJISI-IC\IA, Y.

~tifjj:@:7J"j':.l1!!.~J:ifI\ tlijt~*7-;L - p -=- 7 :/lOm:nll¥~lOt-lfti:' ...... , ... #MI-fiZ . 'HjHIllj:: . =J:3&~ Carboniferous brachiopods from Kawai, Hiroshima Prefecture, Southwest japan .. Y ANAGJDA, J. Elikah~:fr (17:/) IOJ::tf1I.rZ,v.b,>* Nesen ~9=t~c~;t.h0JIiii}.t~~lOfJ~jf\:; ...... '1:'J'HJt=· m**rinl; . GOLSIIAC\:I, F. Urushteni(J from the Permian of Eurasia· ...... ·NAKAMUI~A, K. On some specific aspects of the r,"production of marine ostracods· .. ·IKEY A, N. and OIIISlll, M. llliJ¥HI ::$:mj::f\lOiIiJ\1f;(\l~1tT:ir.1'tI~· ...... *~.}II i¥= . Vli::$:W:rr ~t:7L'I'I'lm 'J';f1' ffiC a illi*,c 10 iJk*fi.!J;I'i1tT:i· ...... J: !Jlf tl!i ~t Computer file system of Japanese Cladophlebis················· ·OGAWA, N. and NISIllII'AKI, N. Ii! JJ Y;1.~ifJ;1~11t£1O Dictyophyllu11l nathorsti ZEILLER IC":) l' -C ...... rAJiili§i1Ji\;tnr, =FJ&tftjj(H?o1lf~ Adiantites lJaY Ginkgoites K ,,:)l'-C· ...... '1'~ I~ * JoB 'll~~~c J: 07J ::--TJil. (Acer L.) 7Hl'ilOfI}~iM c -tlOiiHt*aft ...... ·#DJ )1: fit *v. Some coniferous remains from the Palaeogene Noda Group, Iwate Prefecture, Japan. (Part 3) ...... KI~IURA, T. and HORIUCHI, J. =:m:t'R,~:fITiHc7t;(P-t o fFJ9(!li'l 1O::(::jJJHt U-::t-t1tIl IOMHliic ,,:)l ,-c ...... 'lljWH4!~ . jIf;Jlllii1f~ . ,f1l!JfB$ffJ Jlf*1m:n. R r!flllY,t%) ~!:Ir1~ciW-t 01;f{tIl IO*,Ui~~c ":)l' -C ...... 'IUIIr{;j-M!~ . 1M] FRir'L1: ' ,f1l!JFR$PJ

UJ D~Z.~: Taxonomic studies on some fossil and recent Japanese Balanoidea. Trans. Proc. Palaeont. Soc. Japan, N.S. No. 107, pp. 136-160, pis. 19-22, 1977; No. 108, pp. 161-201, pis. 23- 27, 1977. {tIl 7:;"/ ;f-~tH:tt1}?*'I'~Ci'~ .iilllc~IL\-t 0 b'ftl!:7HtfHhUJ: i) -\"'-t <, b,":)-tJuj'N%I'-t 0 1m rlli 10 ¥!J{* 10 iE*lc J: '0 L M!~b:iSrh 0 t-:: lib Ic7tft[b:ts..-jfJ· L <, E1:;fi: -c'(Fc 10 f,llMjldl9liJf'5E It%; A., c'tJ:iJ' '0 t-::o -:Jfffl,j::ifjj 11F.1!lF;1l':t/iJVJ!j&;-illl::z. f;L -C {, !u:{flO (j'~Wlr-¥rtT11O /.1=.ffl.!'!91lWi~~~-'t" J1l!JlI!(I(J';t;{jllcit1;..-jl 'k fi-'t"i!P.fi 10 ftlf1Elt *t-= rm ftfl ~.hk'ib' I) -C-;/J) 0 0 :;fi:ilifU::l(ltEl::$:i£{tli :to J: O~JJ~~EIO Balanus amphitrite f!l1llf, B. rostratus, Solidbalanus hesperius, Megabalanus tintinnabllium :flfUlf:to J: lY B. crenatus IC":)l'-C, -t.hl? b;WY~¥/.I-C-i:Ji:iia-C-!Jlf?1-lm~fJ; -C- ~ 0 c ~ I) ;f1J.~,:z.~t:b' L -Cftt*IOJf1~IO*,=lr~IOW!tt-=(tICJJ;.-jl ,td~?,\IJ.$(l97tm:z.~M L, Dl,j::fiHI&l'" -C hfJ, '0 t-::fililj:to J:lYfifil"JI.l'M*:z. {, c IC L -C 5J'-mCJf:(FJIC[[.l,....-ji,t I? *"t-::M'l'tHtflo~ • EFJ~HtJ(~J~CJ/&~ICl!'1l""? -c~.L-cmwll¥IO.~K{,c..-j<~j::~IO>*aftlO~~~~mlO.ftK~libk{,IO-C-~0.::$:liJf~KJ:~B ;j~IO{tIl 7:;"/ ;f-mlOj,iJri,'<1-'Ull:JUc~i',(UI9Ic:l1'!j1JQ Lt-::. {t;n:to J: u~:m.j:: :z.jj!tit L t-::ifjjPM!!Ffl':fft!fffJfu7tmlO liJf~K*~Lkc~~LR*~4~$~~~~Kwn~~~K~L-C.~~:z..0.

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New Series No. 109 April 30, 1978

CONTENTS

TRANSACTIONS 684. KOBAYASHI, Teiichi: Discoactinoceras and the Discoactinoceratidae, fam. nov...... 223 685. HIRANO, Hiromichi: Phenotypic substitution of Gaudryceras (A Cretaceous ammonite) ...... 235 686. KIMURA, Tatsuaki and SEKIDO, Sinji: Addition to the Mesozoic plants from the Akaiwa Formation (Upper Neocomian), the Itoshiro Group, Central Honshu, Inner Zone of Japan ...... 259 667. MATSUMOTO, Tatsuro and MURAMOTO, Kikuwo: Further notes on Vasco­ ceratid ammonites from Hokkaido (Studies of the Cretaceous ammonites from Hokkaido and Saghalien-XXXIII) ...... 280 PROCEEDINGS ...... 293