Paleontological Research
Volume 14, Issue 2, 2010
Volumes & issues:
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Early Jurassic (Hettangian - Sinemurian) Ammonites from New Caledonia (French Overseas Territory, Western Pacific)
View Description Hide DescriptionAbstract.Seventeen ammonite taxa are described and placed in their biostratigraphic framework which covers parts of the Hettangian and Early Sinemurian ages. They show on the one hand strong paleogeographic affinities with the western Tethys [Ectocentrites, Paradasyceras and Angulaticeras (Sulciferites) cf. marmoreum Oppel] and, at the same time, less strongly expressed affinities with eastern Pacific areas with Eolytoceras. Nevertheless the Early Jurassic of New Caledonia essentially reveals a strong endemism due to the presence of ammonites like Kammerkarites paucicostatum (Avias) and Ectocentrites thibaudi nov. sp. and to some New Zealand ammonites like Murihikuites mackellari Stevens or Nevadaphyllites (?) pounamuus Stevens. More ubiquitous forms like Arnioceras aff. bodleyi (Buckman) and Phylloceras (?) cf. psilomorphum Neumayr are also present.
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Eocene Mollusca from the Tainohata Formation in Kôbe City, Southwest Japan
View Description Hide DescriptionAbstract.The Tertiary Tainohata Formation of the Kôbe Group has yielded 10 species of Gastropoda and 19 species of Bivalvia. The formation is of late Middle Eocene age on the basis of the dinoflagellate cyst assemblage and radiometric data. The occurrences of the genera Trinacria, Vicarya, and Sulcobuccinum strongly support an Eocene age for the Tainohata Formation. The molluscan fauna shows high endemism at the species level, whereas it is characterized by Tethyan—Indo-West Pacific genera. Two indigenous molluscan assemblages, Potamides-Cyclina and Corbicula, were discriminated. The composition of these assemblages compares with those of the Neogene intertidal assemblages in embayments. This fact indicates that “temporal parallelism” in the shallow embayment assemblages can be traced back to the late Middle Eocene age in the Japanese Islands.
The following 10 new species are proposed herein: Potamides huzitai sp. nov., Cerithideopsilla hondai sp. nov., Crepidula tainohataensis sp. nov., Cantharus (s.l.) andoi sp. nov., Barbatia nodal sp. nov., Trinacria nipponica sp. nov., Trapezium (Neotrapezium) kobe sp. nov., Tellina (Gastranopsis?) sumaensis sp. nov., Corbicula (Corbicula) uejii sp. nov., and Pitar ozakii sp. nov.
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Jaws of a New Species of Nanaimoteuthis (Coleoidea: Vampyromorphida) from the Tuironian of Hokkaido, Japan
View Description Hide DescriptionAbstract.A new Late Cretaceous vampyromorphid coleoid, Nanaimoteuthis yokotai sp. nov. is described on the basis of two lower jaws recovered from the Turonian of Hokkaido, Japan. The lower jaw of this new species consists of equally sized outer and inner lamellae, and the crest portion of the latter is wholly covered by the former. The maximum length of the outer lamella in the holotype attains 63.7 mm, suggesting a remarkably large body size of the living animal. The new specimens reported herein and other occurrences of cephalopod jaws and gladii which were previously described from Hokkaido (Japan) and Vancouver Island (Canada) demonstrate the existence of a comparatively highly diverse coleoid fauna including -in some cases exceptionally large- specimens of the Teuthida, Vampyromorphida, Cirroctopodida, Octopodida, and Sepiida in the Late Cretaceous North Pacific.
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Aulotortus friedli from the Upper Triassic Gravitational Flow Deposits of the Kumagawa River (Kyushu, Southwest Japan)
View Description Hide DescriptionAbstract.The benthic foraminifer Aulotortus friedli is reported from the Upper Triassic carbonates (capped seamount) of the Sambosan Accretionary Complex in Kyushu, Southwest Japan. Specimens were collected from shallow-water limestone clasts in a debris flow sequence near the Ose locality along the Kumagawa River. The limestone clasts mainly represent shoal facies where the benthic foraminifer is extremely abundant. Because of the remarkable preservation of the Japanese specimens, they allow further description of the involutinid A. friedli. In addition, a detailed sedimentary and environmental analysis of the gravitational deposits where A. friedli occurs is given. Using microfacies analysis together with the biostratigraphic range of A. friedli and associated foraminifers, a new interpretation is proposed of a seamount collapse process that occurred during the Norian-Rhaetian and preceded the major collapse event of the Sambosan seamount, which has been placed in the Middle to Late Jurassic.
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SHORT NOTE
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Recognition of Microbunodon (Artiodactyla, Anthracotheriidae) from the Eocene of China
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