Data_Sheet_1_Revised Description of the Early Permian Recumbirostran “Microsaur” Nannaroter mckinziei Based on New Fossil Material and Computed Tomographic Data.ZIP

The early Permian Richards Spur locality of Oklahoma has produced abundant material of numerous terrestrial fossil tetrapods, including various “microsaurs,” several of which are considered to belong to the clade Recumbirostra. We present a new partial skull of the recumbirostran “microsaur” Nannaroter mckinziei; through computed tomography (CT) analysis of both this new specimen and the holotype, we provide an updated description of the taxon. This new description provides novel information regarding several regions that could not be examined previously due to either being absent in the holotype or difficult to access. This includes missing and obscured aspects of the skull roof, braincase, lower jaw, and the palatal region. Furthermore, the new information obtained from this description was used to update phylogenetic character codings of Nannaroter, and a revised phylogenetic analysis was conducted. The results of this updated analysis are congruent with those of other recent phylogenetic analyses of recumbirostran “microsaurs.” This new information adds to the ever-growing body of early tetrapod CT data, which has been, and will continue to be, important in revealing details regarding early tetrapod anatomy, interrelationships, paleoecology, and evolution.

美国俄克拉荷马州早二叠世的理查德斯普尔（Richards Spur）化石点产出了大量陆生化石四足动物标本，涵盖多种“微蜥类（microsaurs）”，其中不少类群被归入斜椎类（Recumbirostra）演化支。本文记述了一件新的斜椎类“微蜥类”——麦肯齐小纳蜥（Nannaroter mckinziei）的部分头骨标本；通过对该新标本与正模标本开展计算机断层扫描（CT）分析，我们对该分类单元进行了更新版描述。本次描述补充了此前因正模标本缺失或难以观察而无法探明的多个区域的全新信息，包括颅顶、脑颅、下颌及腭区中缺失或被遮蔽的细节。此外，基于本次描述获得的新数据，我们更新了麦肯齐小纳蜥的系统发育特征编码，并开展了修订后的系统发育分析。本次分析结果与近期其他斜椎类“微蜥类”的系统发育研究结果一致。本研究新增的数据进一步丰富了早期四足动物的CT扫描数据集，该类数据集此前及未来都将为揭示早期四足动物的解剖结构、亲缘关系、古生态学与演化历程提供重要支撑。