Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
Sci Data. 2018 Nov 6;5:180244. doi: 10.1038/sdata.2018.244.
Understanding the origin and early evolution of squamates has been a considerable challenge given the extremely scarce fossil record of early squamates and their poor degree of preservation. In order to overcome those limitations, we conducted high-resolution X-ray computed tomography (CT) studies on the fossil reptile Megachirella wachtleri (Middle Triassic, northern Italy), which revealed an important set of features indicating this is the oldest known fossil squamate in the world, predating the previous oldest record by ca. 75 million years. We also compiled a new phylogenetic data set comprising a large sample of diapsid reptiles (including morphological and molecular data) to investigate the phylogenetic relationships of early squamates and other reptile groups along with the divergence time of those lineages. The re-description of Megachirella and a new phylogenetic hypothesis of diapsid relationships are presented in a separate study. Here we present the data descriptors for the tomographic scans of Megachirella, which holds fundamental information to our understanding on the early evolution of one of the largest vertebrate groups on Earth today.
理解有鳞目动物的起源和早期进化一直是一个相当大的挑战，因为早期有鳞目动物的化石记录极其稀少，保存状况也很差。为了克服这些限制，我们对化石爬行动物 Megachirella wachtleri（中三叠世，意大利北部）进行了高分辨率 X 射线计算机断层扫描（CT）研究，结果显示了一系列重要特征，表明这是世界上已知最古老的有鳞目化石，比之前最古老的记录早了大约 7500 万年。我们还编译了一个新的系统发育数据集，其中包含大量的双孔类爬行动物（包括形态和分子数据），以研究早期有鳞目动物和其他爬行动物群体的系统发育关系以及这些谱系的分歧时间。对 Megachirella 的重新描述和双孔类爬行动物关系的新系统发育假说在另一项研究中提出。在这里，我们提供了 Megachirella 的断层扫描数据描述符，这些数据对于我们理解当今地球上最大的脊椎动物群体之一的早期进化具有重要意义。
