2021 Fiscal Year Final Research Report

Evolution of neck motion system in tetrapods, revealing from the morphology of occipital condyles

Research Project

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Project/Area Number	17K05698
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Stratigraphy/Paleontology
Research Institution	Kanagawa Prefectural Museum of Natural History
Principal Investigator	Matsumoto Ryoko 神奈川県立生命の星・地球博物館, 企画情報部, 学芸員 (00710138)
Project Period (FY)	2017-04-01 – 2022-03-31
Keywords	四肢動物 / 後頭顆 / 頚椎 / 可動性 / 機能形態
Outline of Final Research Achievements	There are two types of joint in the connection between the skull and neck in tetrapods: mono-articular joint (e.g. reptiles, birds); bi-articular joint (e.g. lissamphibians, mammals). As these differences in joint type are expected to reflect differences in the position and orientation of the range of flexibility in both joint types. The results of this study showed that the bi-articular joint type indicates greater flexibility in the dorsoventral direction, while the mono-articular joint type indicates in the torsion and dorsoventral flexibility. Both joint types share similarity in the restriction of the lateral flexibility. In particular, for the mono-articular joint, it was revealed that although three-axis rotation was expected due to the joints being ball and socket, in fact the rotation was limited to two axes.
Free Research Field	機能形態
Academic Significance and Societal Importance of the Research Achievements	本研究成果は、初期の四肢動物から有羊膜類における首の進化について、機能に裏付けられた議論を可能にした点に意義がある。後頭部の機能的特性を解剖・形態・実験・理論から明らかにした本研究は、機能形態学の新たな領域を開拓し、今後多くの研究に引用され波及効果が大きい。将来の研究課題として、初期の哺乳類における頭部の運動様式と首の進化を見据えている。本研究は、動物の骨格の違いがどのような機能的な違いに反映されているのかという、素朴な疑問に理論と検証に裏付けられた1つの答えを提供することを可能にした。この様な基礎研究の累積が、多くの人が関心を寄せる古生物の復元をより確からしいものにする。