Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming, China.
Department of Earth Sciences, Natural History Museum, London, United Kingdom.
Elife. 2022 Mar 15;11:e75248. doi: 10.7554/eLife.75248.
The early evolutionary history of the armored dinosaurs (Thyreophora) is obscured by their patchily distributed fossil record and by conflicting views on the relationships of Early Jurassic taxa. Here, we describe an early diverging thyreophoran from the Lower Jurassic Fengjiahe Formation of Yunnan Province, China, on the basis of an associated partial skeleton that includes skull, axial, limb, and armor elements. It can be diagnosed as a new taxon based on numerous cranial and postcranial autapomorphies and is further distinguished from all other thyreophorans by a unique combination of character states. Although the robust postcranium is similar to that of more deeply nested ankylosaurs and stegosaurs, phylogenetic analysis recovers it as either the sister taxon of or of the clade + Eurypoda. This new taxon, , represents the first valid thyreophoran dinosaur to be described from the Early Jurassic of Asia and confirms the rapid geographic spread and diversification of the clade after its first appearance in the Hettangian. Its heavy build and distinctive armor also hint at previously unrealized morphological diversity early in the clade's history.
装甲恐龙（装甲亚目）的早期进化历史被其分布不均的化石记录和对早侏罗世分类单元关系的冲突观点所掩盖。在这里，我们描述了一种来自中国云南省下侏罗统冯家河组的早期分化的装甲亚目恐龙，其依据是一个关联的部分骨骼，包括头骨、轴骨、肢骨和装甲元素。它可以根据许多头骨和后肢的独特特征被诊断为一个新的分类单元，并且进一步通过独特的组合特征与所有其他装甲亚目区分开来。尽管坚固的后肢与更深入嵌套的甲龙类和剑龙类相似，但系统发育分析将其恢复为要么是 的姐妹分类单元，要么是 + eurypoda 的姐妹分类单元。这个新的分类单元， ，代表了第一个从亚洲早侏罗世描述的有效装甲恐龙，并证实了该分支在其首次出现于赫塘阶之后的快速地理扩散和多样化。它的厚重结构和独特的装甲也暗示了在该分支历史的早期，存在以前未被认识到的形态多样性。
