A new Middle Triassic arboreal reptile fauna from the Voltziensandstein (Grès à Voltzia) and the recovery of forest ecosystems

三叠纪是生命进化的重要时期，是二叠纪-三叠纪大灭绝后全球生态系统逐渐恢复的时期。在这段时间内，爬行动物在海洋、淡水和陆地环境中经历了主要的进化辐射。最不为人所知的陆地群落之一是森林生态系统，它们在中三叠世早期缓慢地重建。法国阿尔萨斯（Alsace）的volziensandstein （gr<s:1> <s:1> Voltzia）是保存这种生态系统的一套特殊的fossillagerstätten。这个岩石序列产生了丰富的植物群，多种节肢动物和鱼类，以及路易斯·格劳沃格尔（Louis Grauvogel）在20世纪收集的两个未描述的爬行动物分类群。后者之一，分类群A，目前有83个标本，包括两个关节骨骼和保存完好的头骨材料。这种长15厘米的双肢爬行动物保留了四肢的特征，这些特征被认为与树栖攀登有关，骨骼保留了广泛的表皮结构。这些包括硬化的表皮结构，可能被解释为显示滑翔或飞行装置的特征或组成部分。设想中的项目侧重于gr<s:1> Voltzia的爬行动物，它们的解剖结构和系统发育位置，生活方式以及森林栖息地内的生态关系。它整合了以下数据：(1)新的爬行动物分类群A和B的形态，(2)它们发生的fossillagerstätten，以及(3)这些地区保存的丰富的植物群和鱼类，软体动物和节肢动物，以便了解这些非常不寻常的森林爬行动物与它们生活的古生态环境之间的相互作用。这需要对Grauvogel在gr<s:1> Voltzia上收集的现有数据进行详细的分析和一些新的获取。该项目的主要目标是：(1)记录新的爬行动物分类群A和B的形态（包括CT数据），(2)阐明它们的系统发育位置，(3)检查这些分类群的攀爬适应性，(4)研究这些爬行动物的栖息地和假定的生态特征，最后(5)分析外壳和骨骼结构的功能，以决定两种相互竞争的假设：(A)空中滑翔机制或(B)精细的展示结构。

The Triassic was an important phase for the evolution of life, within which a gradual recovery of the global ecosystems after the Permian-Triassic extinction took place. During this time interval, reptiles experienced major evolutionary radiations in marine, freshwater, and terrestrial environments. One of the least understood terrestrial communities were those of forest ecosystems, which were slowly re-established by early Middle Triassic time. An exceptional suite of fossillagerstätten preserving such ecosystems is the Voltziensandstein (Grès à Voltzia) of Alsace (France). This rock sequence yielded rich floras, diverse arthropod and fish faunas, and two undescribed reptile taxa collected by Louis Grauvogel in the 20th century. One of the latter, taxon A, is present with 83 specimens, including two articulated skeletons with well-preserved skull material. This 15 cm long diapsid reptile preserves features in the limbs that are believed to correlate with arboreal climbing, and the skeletons preserve extensive integumentary structures. These include stiffened epidermal structures that might be interpreted as either display features or components of a gliding or flying apparatus.The envisioned project focuses on the reptiles of the Grès à Voltzia, their anatomy and phylogenetic position, mode of life, and ecological relations within the forest habitat. It integrates data on (1) the morphology of the new reptile taxa A and B, (2) the fossillagerstätten at which they occur, and (3) the preserved rich flora and fish, mollusc and arthropod fauna of these localities in order to understand the interactions between these highly unusual forest-dwelling reptiles and the paleoecological context in which they lived. This requires a detailed analysis and some new acquisition of the available data on the Grauvogel collection on the Grès à Voltzia. Principal goals of the project are (1) to document the morphology of the new reptile taxa A and B (including CT data), (2) elucidate their phylogenetic position, (3) examine the climbing adaptations in these taxa, (4) study the habitat and putative ecological traits of these reptiles and finally (5) analyze the function of the integumentary and skeletal structures in order to decide between the two competing hypotheses: (a) an aerial gliding mechanism or (b) an elaborate display structure.