Transactions and Proceedings of the Palaeontological Society of Japan New Series No. 76 Palaeontological Society of Japan December lOth, 1969 Editor: Tokio SHIKA MA Associate Editors : Kiyotaka CHI NZE I a nd Noriy uki IK EY A Officers for 1969- 1970 President: Fuyuji T AKA! Councillors (*Executives) : Kiyoshi ASA NO*, T etsuro HANA I* (Secretary), Kotora HATAI, Itaru HAYAM I, Koichiro IcHIK AWA , Taro KANAYA, Kametoshi KAN· MERA, Teiichi KOBAYASHI, Kenji KONISHI , Tamio KO TAKA , Tatsuro MATSU· MOTO*, Masao MINATO, Hiroshi OzAK I* (T reasurer ), Tokio SHIKAMA* , Fuyuji TAKA!* Executive Committee (Chairman: Fuy uji TAKA!) General Affairs: T etsuro HANA I, Takashi HAMA DA, Yasuhide IwASA KI Membership: Takashi HAMA DA Finance : Hiroshi OzAK I, Saburo KANN O Planning : Hiroshi OZAKI, Hiroshi UJIIE Publications Transactions : Tokio SHIKAMA , Kiyotaka CHI NZEI, Noriyuki IKEYA Special Papers: Tatsuro MATSUMOTO, Tomowo OzAWA " Fossils " : Ki yoshi ASAN O, Yokichi T AKAY ANAG I Fossils on the cover is Gl oborotalia tnmcalulinoides (D'0RBIGNY, 1839). The photograph was taken on a scanning electron microscope, JEOL-JSM- 2, x 100. All communications relating to this journal should be addressed to the PALAEONTOLOGICAL SOCIETY OF JAPAN Geological Institute, Faculty of Science, University of Tokyo, Tokyo 113, Japan Sole a gent : University of Tokyo Press Trans. Proc. Palaeont. Soc. Japan, N:S., No.' 76, pp. 165-176, pls. 18, 19, Dec. 10, 1969 558. LOWER CRETACEOUS AMMONITES FROM THE MIYAKO GROUP PART 3 SOME DOUVILLEICERATIDS FROM THE MIYAKO GROUP IKUWO OBATA Department of Paleontology, National Science Museum, Ueno, Tokyo Tt:f~E3illi*'Ert!l~lltmi:7:/-t-71 r (.:f:-0) 3), 'E\t!lmtl'f.m£ douvilleiceratids: '§rt!l~ llH::EJi:i"":Q7 :/-t-7-1 r 0)? t,, Douvilleiceratidae f.!j.O) Eodouvilleiceras /If!, 2f!!U:: Dou­ villeiceras /If!, 1 f!ll~~t&Zimcll\X Lt.:. fiti1\ff'i.lfit~niTl}BO)J:t:f~ J:: tJ mi:t-H l.-, :fk'!!§'f'i.lfit~ni :IOCJ:l}M,Ga)lpi~ ~fl!~fCiPf::J-'""Ci~I:HT :Q. ;::_ O)EJi:I:HJII~/f:fCfWJT {5-~f'J:, Wl\'?'ti!!fC.t>I::J-:Q~p ID'U.l:tf.J(i"":Q C.~. ~:blsb'""Ci\ffll;flli¥JC:;li):Q. gg~O)~~Ht:.:fi D. mammillatum O);!EI:HfCJ:: tJ, ajjpF.ftJ: G U:fc .lfit~F.f:."OCJ:l}Bf'i.i;.:f:- G <Tl}B Albian O)J:l'fBfc M.l:t~ h:Q <::· ;li) 0?. v'·::>V1?, Eodouvilleiceras /If!, 2 ~O)i.lfi:HiPG, .lfit~~Tl}~ii~J:$ Aptian O)J:$f::)<t ft~h:Q~-~~~T~T"-~~k. ~ m ~ ~ to Dr. Tetsuro HANAI of the University Introduction of Tokyo and to Dr. I taru HAY AMI of Some species of the Lower Cretaceous Kyushu University, for their kind co­ ammonites from the Miyako Group were operation in the field work and in vari· described in my previous papers (1967a, ous other ways. I desire to express my b). Subsequently (HANAI et a!., 1968) the sincere thanks to Professor Tatsuro stratigraphic division and succession of MATSUMOTO of Kyushu University, who selected species of ammonites from the had encouraged me during the course Miyako Group were shown in a table. of this study, shared his precious time On that occasion the Aketo Formation, with me in fruitful discussion, and fur­ the uppermost member of the Group, thermore made a critical review of the was provisionally assigned to the Lower first draft. Thanks are extended to Dr. Albian, without, however, definite indices. Hiroshi OZAKI and Miss Reiko FUSEJIMA In the present part, I describe three spe­ of the National Science Museum for their cies belonging to the family Douvillei­ help in many ways. Financial support ceratidae. The Douvilleiceratidae consist was defrayed by the Ministry of Educa­ of only a few genera but are important tion as the Grant in Aid for Scientific in that they are representative of the Researches. Douvilleicerataceae and comprise good index species of Aptian to Albian ages. Systematic Descriptions I wish to record here my cordial thanks Order Ammonoidea * Received April 1, 1969; read January 25, 1969, at Tokyo. Superfamily Douvilleicerataceae 165 166 1kuwo · 0BATA Family Douvilleiceratidae ward the venter. The ribs start from the umbilical shoulder, slightly concave_ · Subfamily Douvilleiceratinae P ARONA on the flank, and are very gently pro­ & BONARELLI, 1897 jected on the venter in younger stages, but in later stages they become straight, Genus Eodouvilleiceras CASEY, 1961. slightly prorsiradiate on the flank, and Type species.-Douvilleiceras horridum then radially cross the venter. The ribs RIEDEL, 1937 (designated by CASEY, 1961). are broad but very low, and are sepa­ Remarks.-CASEY (1961, p. 191) de· rated by interspaces which are nearly scribed concisely the diagnosis of the as wide as the ribs. The lirae are genus, to which a few species were discernible in the interspaces on the referred (1961, p. 191 ; 1962, p. 260). shell. There are eighteen ribs in a Recently, MATSUMOTO (1968, p. 143) de­ whorl of a late stage (e. g. NSM 7272), scribed a species of the genus from the but six in an earlier whorl (e. g. NSM Tomochi Formation, Kyushu. In this 7264). paper two species from the Miyako At the stage below 5 mm. in diameter, Group are described.· They came from a tubercle appears first on the most in­ flated part of the flank (e. g. NSM 7273). the upper part of the Upper Aptian~ In addition, a . ventro-lateral tubercle appears on the rib at about 7 mm. in Eodouvilleiceras matsumotoi, sp. nov. diameter (e. g. NSM 7264), and lastly a tubercle appears on the umbilical end Pl. 18, figs. 2, 3, 5; Pl. 19, fig. 2; text-fig. 1. of the rib at about 16 mm. in diameter (i. e. NSM 7272). The lateral tubercles Holotype.-NSM 7272 from loc. Hn. are rather clavate in the young stage 4201 (0BATA coll.) .. between 5-8 mm in diameter (e. g. NSM Paratypes.-Two specimens, NSM 7269 7264 and 7272), but become conical later and 7281, from the type locality (OBATA (i. e. NSM 7272). ·In later stages there coiL}; NSM 7263 and 7264 from loc. Hn. are two ventro~lateral tubercles on each 4151 (OBA T A coll.) ; NSM 7268 from the rib, but lateral tubercle is sometimes same locality (HANAI coll.); IGPS 87145, absent. The ventro-lateral tubercles are a fragment, from loc. Hn. 4152 (YEHARA rather spinose and are nearly as large coiL). · as the lateral ones in later stages. The Description.-Whorls are much depres­ umbilical tubercles are much smaller sed and coronate, except for the young thart the lateral and ventro-lateral ones. which shows a rather cadicone stage The suture is rather simple. Follow­ below 10 mm. in diameter. The maxi­ ing WIEDMANN'S formula (1966, p. 34), mum thickness is at some distance it consists of EL(LvLd)U(UvUd)I. E is below the midflank. Width of umbilicu~ deep and of moderate breadth. L is the is fairly wide to moderate, decreasing broadest and is divided into Lv and Ld with growth. The umbilical wall is by a comparatively large, subquadrate high and steep near its base, becomes saddle. Lv is oblique, much smaller rounded upward, passing into a sub­ than E and is asymmetrically incised angular top, slightly above the umbilical with small folioles. Ld is smaller than shoulder, where the whorl is broadest. Lv and is oblique. U is asymmetrically The inflated flanks are convergent to- divided into Uv and Ud by a foliole. 558. Douvilleiceratids fro'rn ·the Miyako Group 167 lmm L___j ~~~,o~r~-~ u.s. v -.; \ u.s. Fig. 1. Eodouvilleiceras matsumotoi sp. nov .. Suture of the holotype, NSM 7272, from the Hiraiga Formation, at whorl-height=3.8 mm, breadth=7.5 mm. Uv is small and situated on the outer and fairly large distance between two side of the umbilical seam. Ud is almost ventro-lateral tubercles. Since the suture vertical and deeper than Uv. I is fairly of the holotype of E. horridum is insuf­ narrow but larger than Ud. The first ficiently preserved and the incision of lateral saddle between E and L is the saddles is uncertain, an exact comparison tallest, massive, asymmetric in outline, cannot be expected between the two with a steeper ventral slope, multipar­ species under consideration. The main tite with several lobules, decreasing in difference between the Miyakoan and breadth toward the top. The saddle the Colombian species is the position of between L and U is subquadrate, and the lateral tubercles. In the described shallowly bipartite at the top. The species. the lateral tubercles are situated saddle between U and I is fairly high below the mid-flank, while in E. horridum and narrow. they are situated rather above the mid­ Remarks.-The holotype, the largest flank. of the present specimens, is much The described species is distinguished smaller than the hitherto known mature from Eodouvilleiceras n. sp. (?) aff. E. specimens of douvilleiceratids, but its horridum (RIEDEL) (MATSUMOTO, 1968, morphological features are distinguish­ p. 143, pl. 2, fig. 2a-d) from the Tomochi ed from the specimens of the known Formation, Kyushu, in that it has a sub­ species. angular, instead of rounded, top slightly Comparison.-The described specimens above the umbilical shoulder and the are closer to the holotype of Eodouvillei­ lateral tubercles which are situated in­ ceras horridum (RIEDEL) (1937, p. 29, pl. side the mid-flank. 6, figs. 1, 2) than to the specimen illust­ Eodouvilleiceras santafecinum (BURCK­ rated by CASEY (1962, p. 261, text-fig. HARDT) from Colombia has more numer­ 90), in the delicate and dense ribbing ous ribs (cf.