The braincase of the early archosaurian reptile Erythrosuchus africanus
The braincase of the early archosaurian reptile Erythrosuchus africanus
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早期祖龙类爬行动物非洲红鳄的脑壳
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发表时间：
2009
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通讯作者：
D. Gower
中科院分区：
文献类型：
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作者：
D. Gower
本文对三叠纪早期始龙类爬行动物Elythrosuhus的脑壳进行了详细描述。所描述的原始龙的多形性特征包括骨化的外侧枕骨、半月凹、位于颈内动脉后腹孔、基蝶突间板、未或不完全骨化的耳囊内侧壁和外淋巴管通道、未被骨分割的转移孔和较短的大隐窝。在最早的始龙中，红尾龙的脑壳被认为比与其他类群有更多的衍生相似性，尽管需要进一步的研究来确定这些相似性是否是同源的。了解非冠群始祖龙的形态对于解决有关现存始龙脑壳特征的有争议的同源性问题以及改进始龙系统发育的估计是重要的。据推测，鳄鱼和鸟类的最新共同祖先缺乏“半月凹”和蝶骨“结节间板”，并具有位于外侧的颈内动脉孔、较短的颈内动脉、完整的交替孔、未骨化的咽鼓管系统和鼓室未充气的成分。
The fimt detailed description of the braincase of the Triassic early archosaurian reptile Elythrosuchus is presented. Features plesiomorphic for archosaurs that are described include an ossified laterosphenoid, a ‘semilunar depression’, posteroventrally positioned internal carotid foramina, a basisphenoid ‘intertuberal plate’, an un- or incompletely ossified medial wall of the otic capsule and channel for the perilymphatic duct, a metotic foramen undivided by bone, and a short lagenar recess. Among the earliest archosaurs, the braincase of Erythrosuchus is considered to share more derived similarities with the erythrosuchid Shansisuchus than with other taxa, although further study is required to ascertain whether these similarities are homologous. An understanding of non crown-group archosaur morphology is important for resolving controversial questions of homology concerning braincase features in extant archosaurs, as well as for improving estimates of archosaur phylogeny. The most recent common ancestor of crocodiles and birds is hypothesized to have lacked a ‘semilunar depression’ and basisphenoid ‘intertuberal plate’, and to have had laterally positioned internal carotid foramina, a short lagena, an undivided metotic foramen, an unossified eustachian system, and elements of the tympanic cavity that were not pneumatized.