解决早期羊膜的系统发育关系,尤其是茎爬行动物,仍然是一个难题。保存完好的茎爬行动物标本的三维形态分析可以揭示重要的解剖数据并阐明系统发育区域。这里,我们提出了不寻常的早期二叠纪茎爬行动物Bolosaurusmajor的第一个彻底描述,包括对bolosaurid脑壳的第一个全面描述。我们描述了先前模糊的腭细节,允许深入了解牛龙喂养机制。讲台的各个方面,腭,下颌骨,和神经头颅表明B.major咬伤特别强烈。我们还发现B.major有一个令人惊讶的细长骨,类似于中二叠纪茎爬行动物Macroletterpoezicus,与其他古生代羊膜相比,这可能表明听力能力增强(例如,captorhinids).我们将新的解剖信息整合到一个大的系统发育矩阵中(150个OTU,590性状),以探讨茎爬行动物之间的Bolosauridae关系。我们的分析通常发现了一种近亲性的“Pararepilia”,\“并发现Bolosauridae在CaptorinidaeAraeoscelidia之后发散。我们还将B.major包含在一个较小的矩阵中(10个OTU,27个字符)旨在探索Bolosauridae的相互关系,并发现Bolosaurus的所有物种都是单系的。虽然爬行动物的关系仍需要进一步调查,我们的系统发育表明,在古生代茎爬行动物中,阻抗匹配耳的重复进化。
Resolving the phylogenetic relationships of early amniotes, in particular stem reptiles, remains a difficult problem. Three-dimensional morphological analysis of well-preserved stem-
reptile specimens can reveal important anatomical data and clarify regions of phylogeny. Here, we present the first thorough description of the unusual early Permian stem
reptile Bolosaurus major, including the first comprehensive description of a bolosaurid braincase. We describe previously obscured details of the palate, allowing for insight into bolosaurid feeding mechanics. Aspects of the rostrum, palate, mandible, and neurocranium suggest that B. major had a particularly strong bite. We additionally found B. major has a surprisingly slender stapes, similar to that of the middle Permian stem
reptile Macroleter poezicus, which may suggest enhanced hearing abilities compared to other Paleozoic amniotes (e.g., captorhinids). We incorporated our new anatomical information into a large phylogenetic matrix (150 OTUs, 590 characters) to explore the relationship of Bolosauridae among stem reptiles. Our analyses generally recovered a paraphyletic \"Parareptilia,\" and found Bolosauridae to diverge after Captorhinidae + Araeoscelidia. We also included B. major within a smaller matrix (10 OTUs, 27 characters) designed to explore the interrelationships of Bolosauridae and found all species of Bolosaurus to be monophyletic. While
reptile relationships still require further investigation, our phylogeny suggests repeated evolution of impedance-matching ears in Paleozoic stem reptiles.