| Project/Area Number |
26800270
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Osaka Museum of Natural History |
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Principal Investigator |
HAYASHI SHOJI 大阪市立自然史博物館, 学芸課, 学芸員 (60708139)
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| Research Collaborator |
SATO TAMAKI 東京学芸大学, 教育学部, 准教授
NAKAJIMA YASUHISA 東京大学, 大気海洋研究所, 研究員
SANDER MARTIN ボン大学, 古生物学部, 教授
HOUSSAYE ALEXANDRA パリ大学, 研究員
WINTRICH TANJA ボン大学, 古生物学部
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2016: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2015: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2014: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | 化石 / 系統 / 進化 / 骨内部組織 / 海生爬虫類 / 水生適応 / 首長竜類 / 遊泳能力 / 淡水生 / 骨密度 / 系統進化 / 世界最古 / K戦略 / 内温性 |
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| Outline of Final Research Achievements |
Considering that Plesiosauria are the most diverse clade of Mesozoic marine reptiles, their bone histology and bone microanatomy has received little study. Like for other marine tetrapods inhabiting open waters, a cancellous structure has been reported for plesiosaurs. This microanatomy represents a decrease in skeletal mass as an adaptation to fast swimming. This study with extensive samples reveals a more complex pattern and evolutionary trends. Growth marks in limb bones are distinctive, the first appearing at >70% final cortical thickness, and growth mark counts indicate that asymptotic size was reached within 4-6 years. Such rapid growth is only observed in endothermic amniotes today. This suggests that plesiosaurian endothermy evolved in concert with the changes in their axial skeleton and limbs linked to the evolution of underwater flight and may have been an adaptation to cruising in the open marine habitat of plesiosaurs.
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