New reptiles from the Middle Triassic of Germany and the early evolutionary history of lepidosaurs

鳞龙是一个主要的脊椎动物支系，有9.400多个物种组成了一个生态多样性和地理分布广泛的类群。人们对它们的早期进化和多样化仍知之甚少。分子数据表明，现存的两个分支鳞类和蜥蜴可能在三叠纪时期分裂。不幸的是，类鳞龙化石在三叠纪岩石中非常罕见，除了完全建立的鳞头类外，三叠纪岩石中只有很少的零散已知的茎类群(鳞龙纲)。这是由于身体较小，骨骼僵化程度较差，以及小型四足动物保存潜力较好的化石拉格斯塔顿的贫穷所致。在维尔贝格的下库珀(德国西南部巴登-符腾堡州)，科学发掘最近发现了大量小型鳞龙骨骼。对这些发现的骨学分析是耗时的，除了在显微镜下进行广泛的检查外，还需要CT数据，这是识别元素和充分了解经常脱节和严重粉碎的骨骼的3D结构所必需的。拟议项目的目标是对新发现的分类群进行描述和编制文件，根据保存的大小分类研究个体发育，在一个宽阔的底栖纲框架内进行系统发育分析，以及研究鳞龙茎系的特征进化。这个项目将大大增加我们对鳞龙的现代生态和分类多样性最初是如何产生的理解，并将为跳跃爬行动物的一般规模的进化提供更多的线索。

Lepidosaurs are a major vertebrate clade, with more than 9.400 species forming an ecologically diverse and geographically widespread group. Their early evolution and diversification are still poorly understood. Molecular data indicate that the two extant branches, squamates and tuataras, probably split during Triassic time. Unfortunately, lepidosaur-like fossils are very rare in Triassic rocks, which yielded only few fragmentarily known stem taxa (Lepidosauromorpha) apart from the fully established rhynchocephalians. This results from the small body size and poorly ossified skeletons as well as the poverty of fossil Lagerstaetten with good preservation potential for small tetrapods. In the Lower Keuper of Vellberg (Baden-Württemberg, SW Germany), scientific excavations have recently produced a vast number of small lepidosauromorph skeletons. The osteological analysis of these finds is time-consuming, requiring CT data in addition to extensive examination under the microscope, necessary to identify elements and fully understand the 3d structure of the often disarticulated and heavily crushed skeletons. The objectives of the proposed project are the description and documentation of the newly discovered taxa, the study of the ontogeny on the basis of preserved size classes, the phylogenetic analysis in a wide frame of diapsids, and the study of character evolution in the stem line of lepidosaurs. This project will greatly increase our understanding of how the modern ecological and taxonomic diversity of lepidosaurs first arose, and will shed more light on the evolution of diapsid reptiles on a general scale.