A reassessment of Permian parareptiles using 3D imaging technologies, and their importance for early amniote evolution and ecology

二叠纪时期是地球历史上现代陆地生态系统形成的时期，这些生态系统的主要组成部分是四足动物（完全陆地四足动物）。羊膜动物传统上分为姊妹分支Synapsida（现代哺乳动物的进化谱系）和Sauropsida（现代爬行动物和鸟类的进化谱系）。其中一个在二叠纪期间多样化的早期古生物群是Parareptilia，这个分支在二叠纪末获得了世界性的分布，并在二叠纪-三叠纪边界的地球历史上最大的大规模灭绝中幸存下来。然而，仍有很多关于副爬行动物的进化和生态学，特别是在晚二叠世之前，是未知的。俄罗斯的副爬行动物代表了广泛的和未充分研究的二叠纪地区的组成部分，因为有重大的差距，在我们的知识，他们的解剖，系统发育的相互关系，古生态学，和古地理学。此外，内部和相互关系的parareptiles和早期anterotes作为一个整体，是远远没有解决和几个传统的假设最近受到挑战。为了解决其中的一些问题，我们提出了一个深入的合作德俄研究项目，重新评估选定的成员独特的俄罗斯parareptile动物群（包括分支Nycteroleteridae，Bolosauridae，Nyctiphruretidae，Lanthanosuchoidea）使用现代方法。为了实现这一目标，我们提出的研究将利用最先进的3D成像技术，特别是同步加速器和微型CT扫描和俄罗斯parareptile类群的3D分割，特别是他们的头骨，以阐明关于他们的解剖学的新细节。从这些新数据中获得的信息将用于修订和更新的描述，扩展和修订的系统发育分析，定量分析和宏观进化解释。总的来说，这项研究的目的是提供一个更好的了解俄罗斯parareptiles，并促进这些类群的整合到更大的图片在晚古生代的古陆演化。重新评估这些俄罗斯parareptile分支也将有助于测试的单系Parareptilia，这从来没有得到充分的评估，因为成立的分支。

The Permian period was a time in Earth’s history in which modern terrestrial ecosystems were taking form, a major component of these ecosystems were amniotes (fully terrestrial tetrapods). Amniotes are traditionally divided into the sister-clades Synapsida (the evolutionary lineage of modern mammals) and Sauropsida (the evolutionary lineage of modern reptiles and birds). One of the early amniote groups that was diversifying during the Permian was Parareptilia, with this clade gaining a cosmopolitan distribution by the end of the Permian and surviving the greatest mass extinction in Earth’s history at the Permian-Triassic boundary. However, there is still much that is not known regarding parareptilian evolution and ecology, especially prior to the late Permian. The Russian parareptiles represent an extensive and understudied component of Permian localities, as there are major gaps in our knowledge of their anatomy, phylogenetic interrelationships, palaeoecology, and biogeography. Moreover, the intra- and interrelationships of parareptiles and early amniotes as a whole, are far from resolved and several traditional hypotheses have recently been challenged. To resolve some of these issues, we propose an in-depth collaborative German-Russian research project to re-evaluate selected members of the unique Russian parareptile fauna (including the clades Nycteroleteridae, Bolosauridae, Nyctiphruretidae, Lanthanosuchoidea) using modern approaches. In order to accomplish this our proposed research will utilize state-of-the-art 3D-imaging technologies, specifically synchrotron and micro-CT scanning and 3D segmentation of Russian parareptile taxa, especially their skulls, in order to elucidate new details regarding their anatomy. The information obtained from this new data will be used for revised and updated descriptions, expanded and revised phylogenetic analyses, quantitative analyses, and macroevolutionary interpretations. Overall, this research aims to provide a better understanding of Russian parareptiles and to facilitate the integration of these taxa into the bigger picture of amniote evolution during the late Palaeozoic. Re-evaluating these Russian parareptile clades will also be instrumental for testing the monophyly of Parareptilia, which has never been adequately assessed since the inception of the clade.