Data from: The tetrapod fauna of the upper Permian Naobaogou Formation of China: a new species of Elginia (Parareptilia, Pareiasauria)

The pareiasaur fossil record in China is poor compared to that of Russia or South Africa. A new pareiasaur specimen is here reported from the upper Permian Naobaogou Formation of the Daqing Mountains, Nei Mongol, China. It is recognized as a new species of Elginia, a taxon otherwise known only from the upper Permian Cutties Hillock Sandstone of Scotland. Diagnostic features include a moderately developed cheek flange; prominent otic notch (formed between squamosal and quadratojugal at the posterior margin of the temporal plate); enlarged supraorbital bosses on prefrontal, postfrontal, and postorbital; a hypertrophied supratemporal horn, and squamosal horn prominently projecting posteriorly from caudal margin of temporal plate. The new taxon is differentiated from E. mirabilis by a well-developed and crescentic postfrontal boss, which is the largest among a series of circumorbital bosses; upper orbital border distinctly domed with a smooth rather than angled anterodorsal margin; lesser developed cranial bosses, basal confluence of the transverse process and postzygapophysis produces at horizontal flange in some dorsal vertebrae. The new discovery significantly extends the geographic distribution of Elginia and Elginiidae.

与俄罗斯、南非的副爬行动物（pareiasaur）化石记录相比，中国的该类群化石记录较为匮乏。本文报道了一件产自中国内蒙古大青山晚二叠世脑包沟组（Naobaogou Formation）的副爬行动物新标本。该标本被归入埃尔金龙属（Elginia）的一个新物种，该属此前仅发现于苏格兰晚二叠世卡蒂希尔砂岩组（Cutties Hillock Sandstone）。该新种的鉴别特征包括：中等发育的颊突；显著的耳凹（由鳞骨与方轭骨在颞板后缘之间形成）；前额骨、后额骨及眶后骨上具膨大的眶上隆起；膨大的颞上角，以及从颞板尾缘显著向后突出的鳞骨角。该新分类单元与奇异埃尔金龙（E. mirabilis）的区别如下：具发育良好且呈新月形的后额骨隆起，该隆起为一系列眶周隆起中体积最大者；眶上缘明显呈穹隆状，其前背缘光滑而非棱角状；头部隆起相对较弱；部分背椎的横突与后关节突基部愈合，形成水平状突缘。此次新发现显著拓宽了埃尔金龙属及埃尔金龙科（Elginiidae）的地理分布范围。