| Project/Area Number |
06452097
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TANABE Kazushige The University of Tokyo, Graduate school of science, Professor, 大学院・理学系研究科, 教授 (20108640)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGETA Yasunari National Science Museum, Department of Geology, Researcher, 地学研究部, 研究室 (30270408)
ENDO Kazuyoshi The University of Tokyo, Graduate school of science, Assistant Professor, 大学院・理学系研究科, 助手 (80251411)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1994: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Keywords | Cephalopoda / Anatomy / Embryology / Molecular biology / Phylogeny |
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| Research Abstract |
1) Comparative embryological study
On the basis of well-preserved material from various localities throughout the world, Tanabe and Shigeta have investigated the embryonic shell features of the embryonic shells of various ammonoids using a scanning electron microsope, and the results were compared with data on other extant and fossil cephalopods. As a results, it was revealed that the embryonic shell features in ammonoids are quite different from those of nautilids but are quite similar to those of coleoids. Tanabe is now studying with Mr.Kimio Uchiyama of the Toba Aquarium on the embryonic shell development of living Nautilus in aquaria. Details of these studies will be published in a book chapter of "ammonoid Paleobiology" (Plenum Press) in 1996.
2) Comparative anatomical study
Tanabe and Mapes (1995) described the jaws and radula of a Carboniferous ammonoid Cravenoceras from Oklahoma and discussed its phylogenetic implications.
3) Phylogenetic sutdy
In order to realize the phylogenetic position of the Ammonoidea within the Cephalopoda, Tanabe and Landman (American Museum of Natural History, New York) did a cladistic analysis of 14 embryonic and anatomical characters in five operational taxonomic units. As a result, it was realized the Cephalopoda consists of two monophyletic groups, the Nautiloidea and the Neocephalopoda, the latter includes the Sphaerorthocerida, Ammonoidea, and Coleoidea. This result will be published in Novitates in 1996.
4) Molecular biological study
Endo is now doing research on the molecular systematic study on Nautilus, a well-known living fossil. He also is analyzing biomolecules preserved in cephalopod hard tissues to obtain data on molecular evolution.
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