Eel-like swimming in the earliest ichthyosaurs

IVPP-IR > 中科院古脊椎所（2000年以后）

	Eel-like swimming in the earliest ichthyosaurs
	Motani, R ; You, H ; McGowan, C ; Motani, R (reprint author), UNIV TORONTO,DEPT ZOOL,25 HARBORD ST,TORONTO,ON M5S 1A1,CANADA.
	1996-07-25
发表期刊	NATURE
ISSN	0028-0836
卷号	382 期号:6589 页码:347-348
文章类型	Article
摘要	ICHTHYOSAURS are extinct marine reptiles, probably belonging to the Diapsida(1), that ranged from the Early Triassic to Late Cretaceous(2,3). Post-Triassic ichthyosaurs achieved the highest level of aquatic adaptation among reptiles(4), with a streamlined body, lunate tail and a dorsal fin, features exemplified today by thunniform (tuna-like) fishes. However, little is known of how such a body plan evolved from a terrestrial diapsid. Here we report the most complete specimen of the oldest known ichthyosaur, Chensaurus, representing a transition between the two body plans. The specimen, which has a partial skin impression, has a small caudal fin, a long and narrow body, and a high presacral vertebral count. These features all suggest an anguilliform swimming mode. Later ichthyosaurs retained the high vertebral count, but overcame the high swimming costs of this plesiomorphy, achieving a rigid tunniform bauplan by evolving discoidal vertebrae, and a deep fusiform body. Chensaurus therefore seems to be an evolutionary intermediate between the shorter-bodied terrestrial stock from which the group evolved, and advanced thunniform ichthyosaurs.; ICHTHYOSAURS are extinct marine reptiles, probably belonging to the Diapsida(1), that ranged from the Early Triassic to Late Cretaceous(2,3). Post-Triassic ichthyosaurs achieved the highest level of aquatic adaptation among reptiles(4), with a streamlined body, lunate tail and a dorsal fin, features exemplified today by thunniform (tuna-like) fishes. However, little is known of how such a body plan evolved from a terrestrial diapsid. Here we report the most complete specimen of the oldest known ichthyosaur, Chensaurus, representing a transition between the two body plans. The specimen, which has a partial skin impression, has a small caudal fin, a long and narrow body, and a high presacral vertebral count. These features all suggest an anguilliform swimming mode. Later ichthyosaurs retained the high vertebral count, but overcame the high swimming costs of this plesiomorphy, achieving a rigid tunniform bauplan by evolving discoidal vertebrae, and a deep fusiform body. Chensaurus therefore seems to be an evolutionary intermediate between the shorter-bodied terrestrial stock from which the group evolved, and advanced thunniform ichthyosaurs.
WOS标题词	Science & Technology
URL	查看原文
关键词[WOS]	LOCOMOTION ; SHARKS
收录类别	SCI
语种	英语
WOS研究方向	Science & Technology - Other Topics
WOS类目	Multidisciplinary Sciences
WOS记录号	WOS:A1996UY95000049
引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.205/handle/311034/4043
专题	中科院古脊椎所（2000年以后）
通讯作者	Motani, R (reprint author), UNIV TORONTO,DEPT ZOOL,25 HARBORD ST,TORONTO,ON M5S 1A1,CANADA.
作者单位	1.ROYAL ONTARIO MUSEUM, DEPT PALEOBIOL, TORONTO, ON M5S 2C6, CANADA 2.INST VERTEBRATE PALEONTOL & PALEOANTHROPOL, BEIJING 100044, PEOPLES R CHINA
推荐引用方式 GB/T 7714	Motani, R,You, H,McGowan, C,et al. Eel-like swimming in the earliest ichthyosaurs[J]. NATURE,1996,382(6589):347-348.
APA	Motani, R,You, H,McGowan, C,&Motani, R .(1996).Eel-like swimming in the earliest ichthyosaurs.NATURE,382(6589),347-348.
MLA	Motani, R,et al."Eel-like swimming in the earliest ichthyosaurs".NATURE 382.6589(1996):347-348.

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