Survivorship and recovery of early triassic tetrapods following the permo-triassic extinction event

在已知的五次大灭绝事件中，二叠纪-三叠纪灭绝事件被一致认为是地球历史上最严重的灭绝事件。普遍的观点是，70-90%的物种在2.51亿年前灭绝。物种死亡率高的这种估计是基于对低分类分辨率（科一级群体）的等级研究。我自己的调查，使用更高分辨率的系统发育研究（种和属），表明陆生脊椎动物（四足动物）经历了低灭绝压力在二叠纪-三叠纪灭绝事件。

Of the five known mass extinction events, the Permo-Triassic extinction event is regarded unanimously as the most severe in Earth history. The consensus view has been that 70-90% of species became extinct 251 million years ago. Such estimates of high species mortality were based on ranks-based studies of low taxonomic resolution (family-level groups). My own investigations, using phylogenetic studies of higher resolution (species and genera), suggest that terrestrial vertebrates (tetrapods) experienced low extinction pressure during the Permo-Triassic extinction event.