Paleontological Research ISSN 1342-8144 Formerly Transactions and Proceedings of the Palaeontological Society of Japan Vol. 4 No.4 December 2000 The Palaeontological Society of Japan Co-Editors Kazushige Tanabe and Tomoki Kase Language Editor Martin Janal (New York, USA) Associate Editors Jan Bergstrom (Swedish Museum of Natural History, Stockholm, Sweden), Alan G. Beu (Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand), Satoshi Chiba (Tohoku University, Sendai, Japan), Yoichi Ezaki (Osaka City University, Osaka, Japan), James C.lngle, Jr. (Stanford University, Stanford, USA), Kunio Kaiho (Tohoku University, Sendai, Japan), Susan M. Kidwell (University of Chicago, Chicago, USA), Hiroshi Kitazato (Shizuoka University, Shizuoka, Japan), Naoki Kohno (National Science Museum, Tokyo, Japan), Neil H. Landman (Amemican Museum of Natural History, New York, USA), Haruyoshi Maeda (Kyoto University, Kyoto, Japan), Atsushi Matsuoka (Niigata University, Niigata, Japan), Rihito Morita (Natural History Museum and Institute, Chiba, Japan), Harufumi Nishida (Chuo University, Tokyo, Japan), Kenshiro Ogasawara (University of Tsukuba, Tsukuba, Japan), Tatsuo Oji (University of Tokyo, Tokyo, Japan), Andrew B. Smith (Natural History Museum, London, Great Britain), Roger D. K. Thomas (Franklin and Marshall College, Lancaster, USA), Katsumi Ueno (Fukuoka University, Fukuoka, Japan), Wang Hongzhen (China University of Geosciences, Beijing, China), Yang Seong Young (Kyungpook National University, Taegu, Korea) Officers for 1999-2000 President: Kei Mori Councillors: Kiyotaka Chinzei, Takashi Hamada, Yoshikazu Hasegawa, Itaru Hayami, Hiromichi Hirano, Noriyuki Ikeya, Junji Itoigawa, Tomoki Kase, Hiroshi Kitazato, Itaru Koizumi, Haruyoshi Maeda, Ryuichi Majima, Makoto Manabe, Hiroshi Noda, Ikuwo Obata, Kenshiro Ogasawara, Terufumi Ohno, Tatsuo Oji, Tomowo Ozawa, Yukimitsu Tomida, Tsunemasa Saito, Takeshi Setoguchi, Kazushige Tanabe, Akira Yao Members of Standing Committee: Hiroshi Kitazato (General Affairs), Tatsuo Oji (Liaison Officer), Makoto Manabe (Finance), Kazushige Tanabe (Editor in Chief, PRJ, Tomoki Kase (Co-Editor, PRJ, Ryuichi Majima (Planning), Hiromichi Hirano (Membership), Kenshiro Ogasawara (Foreign Affairs), Haruyoshi Maeda (Publicity Officer), Noriyuki Ikeya (Editor, 'Fossils'), Yukimitsu Tomida (Editor in Chief, Special Papers), Tamiko Ohana (Representative, Union of Natural History Societies). Secretaries: Masanori Shimamoto, Takao Ubukata (General Affairs), Hajime Taru (Planning), Tokuji Mitsugi (Membership), Shuko Adachi (Foreign Affairs), Kazuyoshi Endo, Yasunari Shigeta, Takenori Sasaki (Editors of PRJ, Akira Tsukagoshi (Editor of 'Fossils'), Naoki Kohno (Editor of Special Papers), Hidenori Tanaka (Publicity officer) Auditor: Nobuhiro Kotake Notice about photocopying: In order to photocopy any work from this publication, you or your organization must obtain permission from the following organization which has been delegated for copyright for clearance by the copyright owner of this publication. Except in the USA, Japan Academic Association for Copyright Clearance (JAACC), 41-6 Akasaka 9- chome, Minato-ku, Tokyo 107-0052, Japan. Phone: 81-3-3475-5618, Fax: 81-3-3475-5619, E-mail: [email protected] In the USA, Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. Phone: (978)750-8400, Fax: (978)750-4744, www.copyright.com Cover: Idealized sketch of Nipponites mirabilis Yabe, a Late Cretaceous (Turonian) nostoceratid ammonite. Various reconstructions of the mode of life of this species have been proposed, because of its curiously meandering shell form (after T. Okamoto, 1988). All communication relating to this journal should be addressed to the PALAEONTOLOGICAL SOCIETY OF JAPAN c/o Business Center for Academic Societies, Honkomagome 5-16-9, Bunkyo-ku, Tokyo 113-8622, Japan Visit our society website at http://ammo.kueps.kyoto-u.ac.jp/palaeontl Paleontological Research, vol. 4, no. 4, pp. 231-234, December 30,2000 © by the Palaeontological Society of Japan Gyronautilus, a new genus of Triassic Nautilida from South Primorye, Russia YURI D. ZAKHAROV' and YASUNARI SHIGETA2 1 Federal Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Science, Vladivostok 690022, Russia (e-mail: [email protected]) 2Department of Geology and Paleontology, National Science Museum, 3--23--1 Hyakunincho, Shinjuku-ku, Tokyo, 169-0073 Japan (e-mail: [email protected]) Received 25 April 2000; Revised manuscript accepted 10 August 2000 Abstract. A new genus of Triassic Nautilida, Gyronautilus, is proposed for material from the Lower Triassic of South Primorye, Russia. The new genus differs from previous known genera of the family Grypoceratidae by its gyroconic shell with subrectangular whorl sections and a near-marginal siphuncle. A new subfamily, Gyronautilinae, within the Grypoceratidae is also proposed. Key words: Early Triassic, Gyronautilus, Nautilida, Olenekian, South Primorye Introduction subdharmus Kiparisova and Koninckites? sp., the brachio­ pod Lingula sp., the bivalves Promyalina vetusta Bencke The Triassic deposits in South Primorye, Far East of and Eumorphotis multiformis (Bittner) in the middle part, and Russia, yield well-preserved nautilids, some of which spe­ the cephalopods Hedenstroemia sp., Meekoceras boreale cies have been described by previous authors (Diener, Diener, M. subcristatum Kiparisova, Ambites sp. indet., and 1895; Kiparisova, 1954, 1961; Zakharov, 1978). Syringo­ Gyronautilus praevolutum (Kiparisova), as well as the ceras praevolutum was proposed by Kiparisova (1961) on brachiopods Abrekia sulcata Dagys and Lingula borealis the basis of a single small specimen collected by N.K. Bitner in the upper part (Zakharov and Popov, 1999). Trifonov in 1948 from the' Lower Triassic of the Abrek Bay These fossils suggest the Upper Induan in the middle part area, about 45 km southeast of Vladivostok. The exact lo­ and the Lower Olenekian (lower part of the Hedenstroemia cality and horizon of the specimen were not described, but bosphorensis Zone) in the upper part of the formation. The recently we found a large and complete specimen identified Induan/Olenekian boundary is located at 55 m above the as S. praevolutum from the type locality (Figure 1). In this base of the formation. paper we describe the early to adult features of the species, The overlying Zhitkov Formation consists mainly of dark and propose a new subfamily and genus based on the grey siltstone with calcareous nodules and intercalations of specimen. fine-grained sandstone. The formation is more than 87.3 m The specimen utilized herein is deposited in the National thick in the section studied. The ammonoids Inyoites spicini Science Museum, Tokyo (NSM). Zakharov, Parahedenstroemia conspicienda Zakharov, Prosphingitoides magnumbilicatus (Kiparisova), Dienero­ Note on Stratigraphy ceras sp., Meekoceras boreale Diener, M. sUbcristatum Kiparisova, Koninckites aft. timorense Wanner, K. varaha The Lower Triassic strata exposed along the eastern (Diener), Arctoceras septentrionale (Diener), and Flemingi­ coast of Abrek Bay are lithostratigraphically divided into two tes sp., as well as the bivalves Phaedrysmocheilus sp. and formations, the Lazurnaya Bay and Zhitkov Formations in Promyalina putiatinensis (Kiparisova) were found in the upward sequence, as defined by Zakharov (1996, 1997) lower part of the formation, suggesting an early Olenekian along the shore of Lazurnaya (= Shamara) Bay and the east age (upper part of the Hedenstroemia bosphorensis Zone). coast of Russian Island near Vladivostok. The Lazurnaya Bay Formation unconformably overlies the Paleontological description Permian Abrek Formation and consists of basal conglomer­ ate and gray, fine-grained, bedded sandstone with lenses of Order Nautilida Agassiz, 1847 coquinoid calcareous sandstone. Its thickness is 57.9 m in Superfamily Trigonocerataceae Hyatt, 1884 the section surveyed. It contains the ammonoids Gyronites Family Grypoceratidae Hyatt in Zittel, 1900 232 Yuri D. Zakharov and Yasunari Shigeta 1 em 2 Sea of Japan Figure 2. Whorl cross sections of Gyronautilus praevolutum (Kiparisova), NSM PM16132, at whorl height of 18.0 mm (1) and 39.3 mm (2). S: siphuncle. Figure 1. Map showing the fossil locality in South Primorye, Far East Russia. Subfamily Gyronautilinae, subf. nov. Venter Diagnosis. - Gyroconic shell with flattened venter. Suture with distinct ventral and lateral lobes. Figure 3. Suture line of Gyronautilus praevolutum Composition. - One genus: Gyronautilus Zakharov and (Kiparisova), NSM PM16132, at whorl height of 25 mm. Shigeta. Remarks.-Kiparisova (1961) described "Syringoceras" praevolutum in 1961 from the Lower Triassic of South Holotype.-CGM 1215504 figured by Kiparisova (1961, Primorye and included it in the family Syringonautilidae. pl.4, fig.2) from the Lower Triassic (Olenekian?) of Abrek Shimansky (1962) recognized four subfamilies in the family Bay in South Primorye, Russia. Grypoceratidae: Domatoceratinae, Grypoceratinae, Syringo­ Material.-One specimen, NSM PM16132. nautilinae and Clymenonautilinae. During our investigation Description.-Shell moderately large, reaching 92.6 mm of Kiparisova's species we experienced problems with deter­ in diameter, rapidly expanding gyroconic conch, consisting mination of its subfamily assignment, and concluded that it of 1.7 whorls. Embryonic shell 18.2 mm long, exogastrically seems to be a representative of a new, previously unknown curved, consisting of 0.4 whorl, attaining 7.4