2010 Fiscal Year Final Research Report
The origin of cephalopods inferred from shell structure, ontogeny and anatomy
| Project/Area Number |
20540455
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SASAKI Takenori The University of Tokyo, 総合研究博物館, 准教授 (70313195)
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| Co-Investigator(Kenkyū-buntansha) |
TANABE Kazushige 東京大学, 理学系研究科, 教授 (20108640)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 系統 / 進化 / 多様性 |
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| Research Abstract |
The consequences of our research include four main topics. (1) Apomorphic or plesiomorphic characters were determined in "living fossil" Nautilus pompilius by comparing characters states of Nautilus with those of other cephalopods and molluscs. (2) Based on ontogenetic data on Nautilus embryo, a new hypothesis was proposed concerning the origin of cephalopod body plan from a primitive conchiferan stage. (3) High diversity of modern-type coleoidean cephalopods in the Cretaceous was revealed by detailed examinations of fossil jaws. (4) The cause of the end-Cretaceous extinction in ammonoids was inferred to be a decline of primary producers in the ocean.
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