ABSTRACT

A partial skull (BP/1/7976) of a very large cynodont from the Middle Triassic Cynognathus Assemblage Zone (Cricodon-Ufudocyclops subzone) of South Africa is described. The specimen represents a new gomphodont taxon, Impidens hancoxi, gen. et sp. nov., diagnosed by five sectorial teeth constituting just over half of the length of the upper postcanine tooth row, and enlarged canine and incisor teeth. BP/1/8123, a skull fragment also from the Cricodon-Ufudocyclops subzone, and AMNH FARB 24421, a partial skull from the upper Fremouw Formation of Antarctica, are also referred to the new species. The presence of this taxon in both the upper Fremouw Formation and Cricodon-Ufudocyclops subzone strengthens evidence of biostratigraphic correlation between these units. Impidens hancoxi, with an inferred skull length of up to 460 mm, was a large-bodied and likely omnivorous gomphodont, and may have played the role of apex predator within the tetrapod fauna of the Cricodon-Ufudocyclops subzone.

摘要

描述了来自南非中三叠世犬颚兽组合区（Cricodon-Ufudocyclops 亚区）的一个非常大的犬齿兽的部分头骨 (BP/1/7976) 。该标本代表了一个新的 gomphodont 分类群，Impidens hancoxi，gen。等 sp. 11 月，诊断为五颗扇形牙齿，占上犬牙列长度的一半多一点，犬齿和门牙增大。BP/1/8123（同样来自Cricodon-Ufudocyclops 亚区的头骨碎片）和 AMNH FARB 24421（来自南极洲 Fremouw 组上部的部分头骨）也被称为新物种。该分类群在上部 Fremouw 组和Cricodon-Ufudocyclops 中的存在子带加强了这些单元之间生物地层相关性的证据。Impidens hancoxi推测的头骨长度可达 460 毫米，是一种体型庞大且可能是杂食性的角齿兽，可能在Cricodon-Ufudocyclops 亚区的四足动物群中扮演着顶级捕食者的角色。