1987 Fiscal Year Final Research Report Summary
EVOLUTIONARY PALEOBIOLOGY OF CHAMBERED CEPHALOPDS
| Project/Area Number |
61480028
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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 | UNIVERSITY OF TOKYO |
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Principal Investigator |
TANABE KAZUSHIGE FACULTY OF SCIENCE, UNIVERSITY OF TOKYO, ASSOCIATE PROFESSOR, 理学部, 助教授 (20108640)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA HARUYOSHI FACULTY OF SCIENCE, KOCHI UNIVERSITY, RESEARCH ASSISTANT, 理学部, 助手 (10181588)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Cephalopoda / Ammonoidea / Nautiloidea / Hokkaido / life history / Functional morphology / 機能形態 / タフォノミー |
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| Research Abstract |
Evolutionary paleobiological, aspects of modern and fossil chambered cephalopods were analyzed, with special reference to ammonites and modern Nautilus. As a result, the following lines of evidence were made clear.
1. Wide variety of adaptive design for streamling among Cretaceous ammonites was suggested from vomparative shell shape analysis of many species from Hokkaido.
2. Embryonic origin of ammonite juvenile shells (ammonitellas) was inferred from comparative SEM observation of microornament with other molluscan embryonic shells.
3. Taphonomic process of ammonite death assemblages in the Upper Cretaceous of Hokkaido was considered from careful observation of mode of fossil occurrence.
4. Feeding habits of ammonites were considered on the basis of comparative anatomy of jaw apparatuses of ammonites and modern Nautilus.
5. Morphologic variation of soft and haed tissues in Nautilus pompilius was analyzed on the basis of specimens from the Philippines and Fiji, and its evolutionary and ecological implications were considered.
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