Revision of the Tanzanian dicynodont Dicynodon huenei (Therapsida: Anomodontia) from the Permian Usili Formation
Revision of the Tanzanian dicynodont Dicynodon huenei (Therapsida: Anomodontia) from the Permian Usili Formation
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DOI：
10.7717/peerj.7420
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发表时间：
2019-08-22
期刊：
影响因子：
2.7
通讯作者：
Kammerer, Christian F.
中科院分区：
文献类型：
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作者：
Kammerer, Christian F.
目前在坦桑尼亚的晚二叠纪Usili组中发现了一种Dicynodon huenei Haughton， 1932。对已知的坦桑尼亚材料的重新研究表明，它们代表了两种不同的形态，在这里被认为是单独的分类群。虎斑蝶的全型不属于双齿目，而是被转移到Daptocephalus属（但保留为一个有效种，Daptocephalus huenei comb）。11月)。然而，来自Usili组的许多已发表的双齿状齿标本可用于双齿状齿，并且在这里被认为是一个新种（Dicynodon angielczyki sp. 11 .）。Dicynodon angielczyki可以与其南非同属Dicynodon lacerticeps区分开来，因为它们的鳞片和颊柱下的鳞片扩张以及颞窗后鳞片的弯曲后外侧扩张。在系统发育分析中，angelelczyki双齿龙和huenei双齿龙分别属于双齿龙和Daptocephalus。这些结果表明，晚二叠世大型双齿兽的盆地地方性比先前认为的要高，与早三叠纪的世界主义形成鲜明对比。
A single species of the dicynodontoid dicynodont Dicynodon is currently recognized from the late Permian Usili Formation of Tanzania: Dicynodon huenei Haughton, 1932. Restudy of the known Tanzanian materials of D. huenei demonstrates that they represent two distinct morphotypes, here considered separate taxa. The holotype of D. huenei is not referable to Dicynodon and instead is transferred to the genus Daptocephalus (but retained as a valid species, Daptocephalus huenei comb. nov.). A number of published dicynodontoid specimens from the Usili Formation, however, are referable to Dicynodon, and are here recognized as a new species (Dicynodon angielczyki sp. nov.) Dicynodon angielczyki can be distinguished from its South African congener Dicynodon lacerticeps by the presence of an expansion of the squamosal and jugal beneath the postorbital bar and a curved, posterolateral expansion of the squamosal behind the temporal fenestra. Inclusion of Dicynodon angielczyki and D. huenei in a phylogenetic analysis supports their referral to Dicynodon and Daptocephalus (respectively). These results indicate higher basinal endemism in large late Permian dicynodonts than previously thought, a sharp contrast to the cosmopolitanism in the group in the earliest Triassic.