Tarailo David A
Department of Earth & Environmental Sciences, University of Iowa, Iowa.
J Morphol. 2018 Dec;279(12):1840-1848. doi: 10.1002/jmor.20906. Epub 2018 Nov 5.
Temnospondyl amphibians experienced a geologically brief interval of success in the wake of the end-Permian mass extinction. This study examines the relationship between taxonomic and ecological diversity of temnospondyls across the Permian-Triassic boundary in the Karoo Basin of South Africa. Ecomorphological diversity, as implied by differences in cranial shape, was incorporated into the study by the use of a landmark-based geometric morphometric analysis. Both taxonomic diversity and cranial disparity are low during the Permian and increase across the Permian-Triassic boundary. Taxonomic diversity is stable through the Triassic, but disparity shows subsequent increases during the Olenekian and Anisian. Temnospondyls are restricted in size immediately following the extinction, but size range fully rebounds by the Olenekian. Cranial shape is heavily influenced by phylogenetic relatedness, and the observed increases in disparity may be partly the result of decreases in the net relatedness of coeval Karoo stereospondylomorph temnospondyls in younger faunas. The increase in community level taxonomic diversity for temnospondyls in the Karoo following the end-Permian mass extinction was likely facilitated by an influx of distantly related and ecologically distinct species.
离片椎目两栖动物在二叠纪末大灭绝之后经历了一段地质时期短暂的成功期。本研究考察了南非卡鲁盆地二叠纪 - 三叠纪边界的离片椎目动物的分类多样性与生态多样性之间的关系。通过基于地标点的几何形态测量分析，将由颅骨形状差异所暗示的生态形态多样性纳入研究。在二叠纪期间，分类多样性和颅骨差异均较低，并在二叠纪 - 三叠纪边界处增加。分类多样性在整个三叠纪保持稳定，但差异在奥伦尼克阶和安尼阶期间随后增加。在灭绝事件刚结束后，离片椎目动物的体型受到限制，但到奥伦尼克阶时体型范围完全恢复。颅骨形状受系统发育相关性的严重影响，观察到的差异增加可能部分是由于较年轻动物群中同时期卡鲁坚头类离片椎目动物的净相关性降低所致。二叠纪末大灭绝之后，卡鲁地区离片椎目动物群落水平的分类多样性增加，这可能是由远缘且生态不同的物种涌入所推动的。
