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首页> 外文期刊>Journal of vertebrate paleontology >Cranial osteology of Guizhouichthyosaurus tangae (Reptilia : Ichthyosauria) from the Upper Triassic of China
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Cranial osteology of Guizhouichthyosaurus tangae (Reptilia : Ichthyosauria) from the Upper Triassic of China

机译：中国上三叠统的唐氏贵州唐古虎（Reptilia：Ichthyosauria）的颅骨学

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摘要

The cranial osteology of the large ichthyosaur Guizhouichthyosaurus tangae from the Wayao Member of the Falang Formation (Lower Carnian, Upper Triassic) of Guizhou, southwest China, is described, based on a well preserved skull and mandible and additional specimens. It can be diagnosed by a suite of cranial characters that include premaxilla without well-developed processus subnarialis, maxilla reaches far anteriorly and has a very long processus postnarialis, orbit of characteristic shape with concave dorsal and straight posterior and ventral margins, small prefrontal that forms only the anterior third of the dorsal orbital margin, postfrontal meets the supratemporal externally, postorbital forms a large part of the lateral margin of the temporal fenestra internally, deep triangular incisura postjugalis, jugal fails to meet quadratojugal externally, short postorbital skull segment; frontals and parietals form sharp ridges lateral to the area of the foramen parietale; parietals form a low and narrow sagittal crest; teeth thecodontously implanted, blunt, conical and without carinae. New data on the postcranial skeleton are also provided. The available evidence indicates that Guizhouichthyosaurus is an advanced member of the Merriamosauria, but more plesiomorphic than the parvipelvians. The taxonomy of the large ichthyosaurs from the Falang Formation remains largely problematic. It appears probable that only two taxa are valid, Guizhouichthyosaurus tangae and Guanlingsaurus liangae. They differ in the length of the snout, the number of the presacral vertebrae, vertebral proportions, the shape of the humerus and fibula, among other features.
机译：基于保存完好的头骨和下颌骨及其他标本，对中国西南部贵州法郎组瓦窑段（上三叠统下卡尼期）的大型鱼龙类唐古奇鱼龙的颅骨进行了描述。可以通过一系列颅骨特征来诊断，包括没有上颌前突发育的上颌前突，上颌前伸很远并且具有较长的后突后突，特征形状的眼眶，背凹凹入，后缘和腹缘平直，形成小的前额叶仅眶后缘的前三分之一，额后部在外侧汇合，而眶后部在内部占颞窗外侧缘的很大一部分，深三角切牙后颌，法律上不能见到四方合法，眶后颅骨短。额叶和顶叶在有孔的顶棚区域的外侧形成锋利的脊;顶骨形成低而狭窄的矢状峰;牙被植入，钝，圆锥形，无隆突。还提供了有关颅后骨骼的新数据。现有的证据表明，贵州龙是Merriamosauria的晚期成员，但比细骨动物更具拟形性。法朗组大型鱼龙的分类学仍然存在很大问题。似乎只有两个分类群是有效的，即唐氏圭龙和两冠龙。它们在口鼻的长度，s前椎骨的数量，椎骨比例，肱骨和腓骨的形状等方面有所不同。

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