TAXONOMY OF THE PROTEROSUCHID ARCHOSAURIFORMS (DIAPSIDA: ARCHOSAUROMORPHA) FROM THE EARLIEST TRIASSIC OF SOUTH AFRICA, AND IMPLICATIONS FOR THE EARLY ARCHOSAURIFORM RADIATION
TAXONOMY OF THE PROTEROSUCHID ARCHOSAURIFORMS (DIAPSIDA: ARCHOSAUROMORPHA) FROM THE EARLIEST TRIASSIC OF SOUTH AFRICA, AND IMPLICATIONS FOR THE EARLY ARCHOSAURIFORM RADIATION
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DOI：
10.1111/pala.12130
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发表时间：
2015-01-01
期刊：
影响因子：
2.6
通讯作者：
Butler, Richard J.
中科院分区：
文献类型：
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作者：
Ezcurra, Martin D.;Butler, Richard J.
原龙科（Proterosuchidae）是化石记录中最早出现的始祖目（即始祖龙及其近亲）分支之一，其中最丰富的样本来自南非的Lystrosaurus组合带（最早三叠纪）。20世纪在南非发现了四种名义上的原龙（proteosuchus fergusi, Chasmatosaurus vanhoepeni， Chasmatosaurus alexanderi和Elaphrosuchus rubidgei），但对其分类的解释存在很大差异。最近的分类学修订认为，弗格森是唯一的有效种，其他名义种都是该分类单元的初级主观同义词。这一建议是基于这样一种解释，即名义种之间的解剖差异可以解释为个体发生变化和/或死后变形的结果。最近发现的多个新的南非元类标本为重新审视它们的分类提供了动力。基于对所有已知标本的全面重新检查，以及对世界各地收集的其他原suchus分类群的检查，我们得出结论，弗氏原suchus的全型是不可诊断的。因此，我们提出了该物种的新种（RC 846）。凡霍佩尼峡谷龙（Chasmatosaurus vanhoepeni）和鲁比盖象龙（Elaphrosuchus rubidgei）被认为是褐皮蛾的主观初级同义词。Chasmatosaurus' alexanderi被认为是一个有效的物种，我们提出了新的组合P.alexanderi梳子。11月第三种P.goweri sp. nov.在单一标本（NMQR 880）的基础上被竖立起来。这里发现的所有三个物种在分类上都不同于先前描述的来自AZ水龙下部的始龙属上颌骨。因此，我们在南非二叠纪-三叠纪大灭绝之后发现了至少四个始龙属物种。我们的研究结果表明，早三叠世始祖类的物种丰富度比以前认为的要高，但直到早三叠世晚期-中三叠世早期，始祖类的形态差异仍然很低，并且没有扩大。
Proterosuchidae is one of the first clades of Archosauriformes (archosaurs and closely related species) to appear in the fossil record, with the richest sample of the group coming from the Lystrosaurus Assemblage Zone (earliest Triassic) of South Africa. Four nominal proterosuchid species were described from South Africa during the twentieth century (Proterosuchus fergusi, Chasmatosaurus vanhoepeni, Chasmatosaurus alexanderi and Elaphrosuchus rubidgei), but interpretations of their taxonomy have been widely disparate. The most recent taxonomic revision concluded that P.fergusi is the only valid species and that the other nominal species are junior subjective synonyms of this taxon. This proposal was based on the interpretation that anatomical differences between the nominal species could be explained as a result of ontogenetic changes and/or post-mortem deformation. The recent discoveries of multiple new South African proterosuchid specimens provide an impetus to revisit their taxonomy. Based upon a comprehensive re-examination of all known specimens, as well as examination of other proterosuchid taxa in collections worldwide, we conclude that the holotype of Proterosuchus fergusi is undiagnostic. As a result, we propose a neotype (RC 846) for the species. Chasmatosaurus vanhoepeni' and Elaphrosuchus rubidgei' are considered subjective junior synonyms of P.fergusi. Chasmatosaurus' alexanderi is considered a valid species, for which we propose the new combination P.alexanderi comb. nov. A third species, P.goweri sp. nov., is erected on the basis of a single specimen (NMQR 880). All three species recognized here are taxonomically distinct from a previously described archosauriform maxilla from the lower Lystrosaurus AZ. As a result, we recognize a minimum of four archosauriform species following the Permo-Triassic mass extinction in South Africa. Our results suggest a greater species richness of earliest Triassic archosauriforms than previously appreciated, but that archosauriform morphological disparity remained low and did not expand until the late Early Triassic - early Mid-Triassic.