Reevaluation of the cranial osteology and phylogenetic position of the early crocodyliform Eopneumatosuchus colberti , with an emphasis on its endocranial anatomy
Reevaluation of the cranial osteology and phylogenetic position of the early crocodyliform Eopneumatosuchus colberti , with an emphasis on its endocranial anatomy
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重新评估早期鳄形始气鳄的颅骨学和系统发育地位，重点是其颅内解剖结构
DOI：
10.1002/ar.24777
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Irmis, Randall B.
中科院分区：
文献类型：
--
作者：
Melstrom, Keegan M.;Turner, Alan H.;Irmis, Randall B.
Eopneumatosuchus colbertiCrompton和Smith， 1980，从一个单一的部分头骨中得知，是一种来自下侏罗统Kayenta组的神秘鳄鱼形。尽管其独特的形态，一个特殊的气动脑壳，以及在鳄鱼形进化的关键时期出现，但对这个分类群的了解相对较少。在这里，我们重新描述颅外形态的e。Colberti，提出关于其颅内解剖的新信息，评估其在早期鳄鱼形动物中的系统发育位置，并寻求更好地表征其生态学。我们的检查阐明了颅缝线路径和颅脑解剖的关键方面。与相关分类群（例如，傲慢原龙）的比较表明，脑病例的极端气性可能在原龙中比以前所认识的更为普遍。计算机断层扫描显示其颅内形态类似于其他早期鳄形动物，特别是非鳄形鳄形动物almadasuchus figarii。然而，在嗅球和大脑半球形态上存在关键差异，这表明鳄鱼的颅内膜并不像以前假设的那样保守。我们的系统发育分析恢复。与先前认为的与Thalattosuchia有亲缘关系的假说相比，colbertia是理查森原蜥蜴和天山苏齿蜥蜴的近亲。先前的研究表明，内耳与半水生鳄鱼形有一些相似之处，但e。具有陆生颅后骨骼形态的原类人猿中的科尔伯蒂使古生态学解释复杂化。
Eopneumatosuchus colbertiCrompton and Smith, 1980, known from a single partial skull, is an enigmatic crocodylomorph from the Lower Jurassic Kayenta Formation. In spite of its unique morphology, an exceptionally pneumatic braincase, and presence during a critical time period of crocodylomorph evolution, relatively little is known about this taxon. Here, we redescribe the external cranial morphology ofE.colberti, present novel information on its endocranial anatomy, evaluate its phylogenetic position among early crocodylomorphs, and seek to better characterize its ecology. Our examination clarifies key aspects of cranial suture paths and braincase anatomy. Comparisons with related taxa (e.g.,Protosuchus haughtoni) demonstrate that extreme pneumaticity of the braincase may be more widespread in protosuchids than previously appreciated. Computed tomography scans reveal an endocranial morphology that resembles that of other early crocodylomorphs, in particular the noncrocodyliform crocodylomorphAlmadasuchus figarii. There are, however, key differences in olfactory bulb and cerebral hemisphere morphology, which demonstrate the endocranium of crocodylomorphs is not as conserved as previously hypothesized. Our phylogenetic analysis recoversE.colbertias a close relative ofProtosuchus richardsoniandEdentosuchus tienshanensis, contrasting with previous hypotheses of a sister group relationship with Thalattosuchia. Previous work suggested the inner ear has some similarities to semi‐aquatic crocodyliforms, but the phylogenetic placement ofE.colbertiamong protosuchids with a terrestrial postcranial skeletal morphology complicates paleoecological interpretation.