Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana
Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana
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DOI：
10.1038/nature01995
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发表时间：
2003-10-09
期刊：
影响因子：
64.8
通讯作者：
Novas, FE
中科院分区：
文献类型：
--
作者：
Apesteguia, S;Novas, FE
蝶齿爬行动物在三叠纪和侏罗纪时期成功地繁衍，但在白垩纪时期几乎灭绝(1)。早白垩纪稀疏的蝶齿动物记录被解释为反映了这一群体的衰落，而被认为是它们的生态继承者——蜥蜴的出现。然而，最近在巴塔哥尼亚晚白垩世地层的发现部分地改变了这种解释。在Cenomanian-Turonian Candeleros组的一个单一地点收集了许多新的蝶类动物Priosphenodon avelasi gen. et sp. nov.的骨骼，在那里它比采石场记录的任何其他四足动物群（例如，鳄鱼目，蛇目，恐龙和哺乳动物）都要丰富（3,4）。前鳞龙的成年标本身长达1米，比以前已知的任何陆地鳞龙都要大。在此，我们利用现有证据提出，蝶形虫并不是白垩纪南美洲陆地生态系统的一个小组成部分，它们被鳞片虫所取代的生态系统推迟到第三纪早期。这一新发现有助于弥合化石记录（大约1.2亿年）中巨大的鸿沟，将早白垩世的蝶龙（5-7）与其现存的近亲（蝶龙）区分开来。
Sphenodontian reptiles successfully radiated during Triassic and Jurassic times, but were driven almost to extinction during the Cretaceous period(1). The sparse Early Cretaceous record of sphenodontians has been interpreted as reflecting the decline of the group in favour of lizards, their suspected ecological successors(2). However, recent discoveries in Late Cretaceous beds in Patagonia partially modify this interpretation. Numerous skeletons of a new sphenodontian, Priosphenodon avelasi gen. et sp. nov., were collected from a single locality in the Cenomanian-Turonian Candeleros Formation, where it is more abundant than any other tetrapod group recorded in the quarry (for example, Crocodyliformes, Serpentes, Dinosauria and Mammalia)(3,4). Adult specimens of Priosphenodon reached one metre in length, larger than any previously known terrestrial sphenodontian. Here we propose, using available evidence, that sphenodontians were not a minor component of the Cretaceous terrestrial ecosystems of South America, and that their ecological replacement by squamates was delayed until the early Tertiary. The new discovery helps to bridge the considerable gap in the fossil record (around 120 million years) that separates the Early Cretaceous sphenodontians(5-7) from their living relatives (Sphenodon).