河北围场下白垩统围场皇家螈(Regalerpeton weichangensis)(两栖类:有尾类)的再研究（英文）

Restudy of Regalerpeton weichangensis(Amphibia: Urodela) from the Lower Cretaceous of Hebei, China

围场皇家螈(Regalerpeton weichangensis)于2009年基于一件产自河北围场下白垩统不完整的骨骼印痕标本命名。然而由于标本变形导致皇家螈的部分解剖学特征被曲解,系统发育位置也存在争论。本文基于8件新标本对该蝾螈的鉴定特征和系统发育位置进行了修订。研究显示,皇家螈是一种腕骨和跗骨骨化的幼态持续型蝾螈,具有独特的特征组合,包括犁骨齿列横向排列、副蝶骨前端呈齿状、基鳃骨II呈三射型,尾长超过吻臀距以及肩胛乌喙骨的乌喙端呈矩形。新的系统发育分析根据三个近裔共性将围场皇家螈、热河螈和胖螈归入蝾螈亚目。此外,它们还与隐鳃鲵亚目共有"肋骨单关节头"这一特征,显示这三种蝾螈可能代表了隐鳃鲵亚目与蝾螈亚目分离时期这一重要演化阶段。

Regalerpeton weichangensis was established in 2009 on an incomplete skeleton preserved mainly as an impression from the Lower Cretaceous of Hebei, China. However, several anatomical characters were misinterpreted due to distortion of the holotype, and its taxonomic position has been in debate. In this paper, R. weichangensis is redescribed based on eight new specimens and its diagnosis and phylogenetic position are re-examined. This work shows that R. weichangensis was a neotenic form with ossified carpals and tarsals. It has a series of unique combination of characteristics including the vomer with a transverse vomerine tooth row, anterior end of the cultriform process of the parasphenoid indented, basibranchial II triradiate, a long tail exceeded the snout-pelvis length and scapulocoracoid with a rectangular coracoid end. Phylogenetic analysis suggests Regalerpeton, Jeholotriton and Pangerpeton should be placed in the suborder Salamandroidea with three synapomorphies. Moreover, they also share unicapitate ribs with Cryptobranchoidea, which indicates that they represent an important stage of evolution in the Cryptobranchoidea-Salamandroidea split.