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The Lower Cretaceous Kuwajima Formation, Tetori Group, Japan

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Bull. Kitakyushu Mus. Nat. Hist. Hum. Hist., Ser. A, 3: 123-133, March 31, 2005 Depositional environments and taphonomy of the bone-bearing beds of the Lower Cretaceous Kuwajima Formation, Tetori Group, Japan Shinji Isaji1 Hiroko Okazaki1 Ren Hirayama2 Hiroshige Matsuoka3 Paul M. Barrett4 Takehisa Tsubamoto5 Mikiko Yamaguchi6 Ichio Yamaguchi6 Tatsuya Sakumoto6 INatural History Museum and Institute, Chiba, 955-2 Aoba-cho, Chuo-ku, Chiba 260-8682, Japan 2School of International Liberal Studies, Waseda University, 1-17-14 Nishiwaseda Shinjuku-ku, Tokyo 169-0051, Japan 3Department of Geology and Mineralogy, Faculty of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8224, Japan ^Department of Palaeontology, The Natural History Museum, London, Cromwell Road, London SW 7 5BD, UK 5Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan 6Shiramine Institute of Paleontology, 10-1-20 Kuwajima, Hakusan, Ishikawa 920-2502, Japan (Received August 21, 2004; accepted September 12, 2004) ABSTRACT—The bone-bearing beds of the Lower Cretaceous Kuwajima Formation (Tetori Group) are described. Three facies of bone-bearing beds (Facies I: carbonaceous sandstones; Facies II: dark grey fine-grained silty sandstones; Facies III: dark greenish-grey mudstones) are present in inter-channel deposits that originated on a floodplain. The grain size of the sediments, and plant and molluscan fossils occurring in each bone-bearing bed, indicate that Facies I was deposited in a peat marsh, Facies II in a shallow lake, and Facies III in a vegetated swamp. Isolated small bones and teeth are the most abundant vertebrate fossils. Common elements in Facies II are aquatic vertebratessuch as fishes and turtles. Facies III is characterized by the occurrence of terrestrial lizards, tritylodontid synapsids and mammals. Vertebrate fossil assemblages in Facies II and III are not mixed with each other even though they both represent parautochthonous assemblages. In contrast, Facies I is allochthonous, and is composed mostly of reworked sediments from Facies II. Depositional environments of the bone-bearing beds are strongly correlated with the composition of their fossil assemblages, indicating that different facies preserve the original faunal differences that existed between the shallow lake and vegetated swamp environments. INTRODUCTION Ishikawa Prefecture, has been a famous fossil locality (Figure 1) since the first discovery of dinosaur remains in During the past two decades, a large number of 1985. However, until recently, only a handful of speci- vertebrate fossils have been recovered from the Mesozoic mens were collected from Kaseki-Kabe, because the thin non-marine formations of Japan. The LowerCretaceous fossiliferous beds, which crop out several metres above Kuwajima Formation has yielded vertebrate fossils from ground level in an almost vertical cliff section, were not several localities. "Kaseki-Kabe", which means literally suitable for large-scale excavations. "Fossil Bluff' in Japanese, in Kuwajima, Hakusan City, In 1997, a road tunnel was driven through the cliff This paper is one of those given at the Symposium of Early Creteceous Terrestrial Biota held in the Kitakyushu Museum of Natural History and Human History on the 1st and 2nd of September in 2003. 121 Shinji Isaji et at. __ V" tunnel H 10m """"-"-" ~~ "^~^~" ~~ :?v&& In-channels •10m Inter-channels in situ tree trunk north Tedori Lake south Figure I. A: Location of Kaseki-Kabe (marked with *. 36 I2*N. 136 38'E). Kuwajima. Hakusan City, Ishikawa Prefecture. Japan. \i: Photograph of Kaseki-Kabe. view from the North West. C: Sketch of Kaseki-Kabe. showing inter-channel and in-channel deposits. Small arrows show the position of an in situ tree trunk. Modilied from Masuda et al.. (1991). section (Figure IB. C) permitting us to observe the fos- mals such as lizards, trilylodontid synapsids and mammals siliferous horizons in detail. So far. three facies of bone- have been newly discovered from several fossiliferous bearing rocks have been identified and numerous verte horizons, which had not been recognized in the cliff brate fossils have been found. The vertebrate fossil section prior to the tunnelling operation. These discov assemblages from Kaseki-Kabe include fishes, anurans. eries revealed that the compositions of the vertebrate fossil turtles, choristoderes. lizards, pterosaurs, sauropods. ther- assemblages are strongly related to the bone-bearing opods, hypsi lophodontian-gradc ornithopods. facies. Such modes of occurrence are noteworthy from a iguanodontians. birds, tritylodonlid synapsids and mam taphonomic point of view. mals (for references, see Figure 2). These materials have The purpose of this study is to describe the modes of been under study by a multi-institutional research team occurrence of vertebrate fossils from the Kuwajima For sponsored by the Shiramine Board of Education and by an mation of Kaseki-Kabe. This paper also discusses the Anglo-Japanese team under the leadership of Susan E. depositional environments and taphonomic processes that Evans (University College London) and Makoto controlled the composition of the small vertebrate fossil Manabe (National Science Museum. Tokyo). assemblages. Among the taxa listed above, small terrestrial ani Institutional abbreviation: SBEI-Shiramine Institute Bone-bearing beds of the Lower Cretaceous Kuwajima Formation 125 Facies I II III carbonaceous sandstones dark grey fine-grained silty sandstones dark greenish-grey mudstones Gastropoda Gastropoda Gastropoda Viviparus onogoensis - (va) Viviparus onogoensis - (va) Viviparus onogoensis - (r) c Si, Micromelania sp. - (r) Micromelania sp. - (r) « ^ Pleuroceridae - (r) Pleuroceridae - (r) |1 Pupilloidea family indet.- (r) s 1 Physidae- (c) Bivalvia Bivalvia Bivalvia Unio ogamigoensis - (va) Unio ogamigoensis - (va) Unio ogamigoensis - (r) Sphaerium sp.- (r) Sphaerium sp.- (r) Plant fragmented & dispersed completely fragmented & accumulated in situ rootlet fossils charophytan zygotes Environ ment peat marsh shallow lake vegetated swamp Bone articulated (< 1%) articulated (< 5%) articu all isolated associated + dispersed (< 1%) associated + dispersed (< 5%) lation isolated + dispersed (> 98%) isolated + dispersed (> 90%) Neopterygii Neopterygii Neopterygii Semionotidae Semionotidae Semionotidae Lepidotes sp. ft Lepidotessp. • Lepidotes sp. ft Sinamiidae Sinamiidae Sinamiidae Sinamia up. Ar'Ar^A' Sinamia sp. ^A"'A"A' Sinamia sp. *** Pachycormidae ft Ostcoglossidae ft Lower Teleostei **• Lower Teleostei * • * Lower Teleostei * Anura Arachaeobatrachia ft Testudines Testudines Testudines Testudinoidea "A" "A" Tcstudinoidea "kit*k-k Testudinoidea * Trionychoidea 'A'"A" Trionychoidea "A"A"A"A' Trionychoidea * Sinemiidae ft Sinemiidae ** family indet. * family indet. "A"^ Squamata Squamata Squamata Anguimorpha ft Sakurasaurus sp. *•*• Paramacellodidae "A"A"A" Amphisbaenia ** Long-bodied animals ••* family indet. * family indet. * family indet. 60 gen. A (herbivore) * J2 gen. B (bicuspid) • gen. C (striated) • E gen. D (amphicoelous) ft gen. E (very small) * C3 gen. F (deep jaw, small teeth)ft M Choristodera Choristodera Choristodera L. IShokawa -si- family indet. * family indet. * family indet. * t: Pterosauria Pterosauria Pterosauria > Type A ft Type A ft TypeB • TypcC • Type D t!r Theropoda Theropoda Theropoda Dromaeosauridae • Dromaeosauridae * Dromaeosauridae * Oviraptorosauria+Therizinosauridae Tyrannosauridae ft ft Theropoda family indet. • Sauropoda Titanosaurlformes *• Omithopoda Omithopoda Omithopoda Iguanodontidae ** Iguanodontidae •• Iguanodontidae -*-* Hypsilophodontian-grade ft Hypsilophodontian-grade * Omithischia indet. ft Aves ?Enantiornithiformes ft Synapsida Synapsida Synapsida Tritylodontidae * Tritylodontidae ft Tritylodontidae 'A"A"A"A' Mammalia Triconodonta ** Multituberculata * Figure 2. Faunal and floral list of three bone-bearing facies found at Kaseki-Kabe and interpretation of their depositional environments. The total number of specimens found during 1997 to 2002 is based on the occurrence of isolated skeletal remains such as a tooth, a scale and a bone fragment. Associated or articulated specimens are counted as one specimen. Vertebrate fossils (•&: known only by one specimen; *: <I0; **: <20; ***: <30; ****: <40; "A": >50). Molluscan fossils (va; very abundant, c; common, r; rare). Sources of information on the fauna are summarized as follows: fishes (Yahumoto, 2000a, 2000b, 2000c, 2002), anurans (Matsuoka, 2000), turtles (Hirayama, 1996, 1997, 1999, 2000), choristoderes (Evans and Matsumoto, personal communication), lizards (Evans and Manabe, 2000), pterosaurs (Unwin and Matsuoka, 2000), sauropods (Barrett et al., 2002), theropods (Manabe et al., 1989, Manabe et al., 200o! Manabe and Barrett, 2000), hypsilophodontian-grade ornithopods (Manabe and Barrett, 2000, Ohashi et al. 2003), iguanodontids (Hasegawa et al. 1995, Manabe and Barrett, 2000), birds (Unwin and Matsuoka. 2000), tritylodontid synapsids (Setoguchi et al., 1999, Matsuoka and Setoguchi, 2000) and mammals (Rougier et al., 1999, Takaim et al., 2001). 126 Shinji Isaji et al. of Paleontology, Hakusan City, Ishikawa Prefecture, Geological Age Japan. The precise age of the Kuwajima Formation is un known because this non-marine formation is barren of reliable index fossils and is not interbedded with marine GEOLOGICAL SETTING strata containing ammonites or other index fossils. The Tetori Group is widely distributed in central However, circumstantial evidence indicates
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  • Titanosauriform Teeth from the Cretaceous of Japan

    Titanosauriform Teeth from the Cretaceous of Japan

    “main” — 2011/2/10 — 15:59 — page 247 — #1 Anais da Academia Brasileira de Ciências (2011) 83(1): 247-265 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 www.scielo.br/aabc Titanosauriform teeth from the Cretaceous of Japan HARUO SAEGUSA1 and YUKIMITSU TOMIDA2 1Museum of Nature and Human Activities, Hyogo, Yayoigaoka 6, Sanda, 669-1546, Japan 2National Museum of Nature and Science, 3-23-1 Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan Manuscript received on October 25, 2010; accepted for publication on January 7, 2011 ABSTRACT Sauropod teeth from six localities in Japan were reexamined. Basal titanosauriforms were present in Japan during the Early Cretaceous before Aptian, and there is the possibility that the Brachiosauridae may have been included. Basal titanosauriforms with peg-like teeth were present during the “mid” Cretaceous, while the Titanosauria with peg-like teeth was present during the middle of Late Cretaceous. Recent excavations of Cretaceous sauropods in Asia showed that multiple lineages of sauropods lived throughout the Cretaceous in Asia. Japanese fossil records of sauropods are conformable with this hypothesis. Key words: Sauropod, Titanosauriforms, tooth, Cretaceous, Japan. INTRODUCTION humerus from the Upper Cretaceous Miyako Group at Moshi, Iwaizumi Town, Iwate Pref. (Hasegawa et al. Although more than twenty four dinosaur fossil local- 1991), all other localities provided fossil teeth (Tomida ities have been known in Japan (Azuma and Tomida et al. 2001, Tomida and Tsumura 2006, Saegusa et al. 1998, Kobayashi et al. 2006, Saegusa et al. 2008, Ohara 2008, Azuma and Shibata 2010).
  • New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Nemegt Formation of Southwestern Mongolia

    New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Nemegt Formation of Southwestern Mongolia

    Bull. Natn. Sci. Mus., Tokyo, Ser. C, 30, pp. 95–130, December 22, 2004 New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Nemegt Formation of Southwestern Mongolia Junchang Lü1, Yukimitsu Tomida2, Yoichi Azuma3, Zhiming Dong4 and Yuong-Nam Lee5 1 Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 2 National Science Museum, 3–23–1 Hyakunincho, Shinjukuku, Tokyo 169–0073, Japan 3 Fukui Prefectural Dinosaur Museum, 51–11 Terao, Muroko, Katsuyama 911–8601, Japan 4 Institute of Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 5 Korea Institute of Geoscience and Mineral Resources, Geology & Geoinformation Division, 30 Gajeong-dong, Yuseong-gu, Daejeon 305–350, South Korea Abstract Nemegtia barsboldi gen. et sp. nov. here described is a new oviraptorid dinosaur from the Late Cretaceous (mid-Maastrichtian) Nemegt Formation of southwestern Mongolia. It differs from other oviraptorids in the skull having a well-developed crest, the anterior margin of which is nearly vertical, and the dorsal margin of the skull and the anterior margin of the crest form nearly 90°; the nasal process of the premaxilla being less exposed on the dorsal surface of the skull than those in other known oviraptorids; the length of the frontal being approximately one fourth that of the parietal along the midline of the skull. Phylogenetic analysis shows that Nemegtia barsboldi is more closely related to Citipati osmolskae than to any other oviraptorosaurs. Key words : Nemegt Basin, Mongolia, Nemegt Formation, Late Cretaceous, Oviraptorosauria, Nemegtia. dae, and Caudipterygidae (Barsbold, 1976; Stern- Introduction berg, 1940; Currie, 2000; Clark et al., 2001; Ji et Oviraptorosaurs are generally regarded as non- al., 1998; Zhou and Wang, 2000; Zhou et al., avian theropod dinosaurs (Osborn, 1924; Bars- 2000).