Pterosaurs from the latest Early and early Middle Jurassic of Argentina and the origin of the Pterodactyloidea

翼龙类祖龙是第一批实现主动拍打飞行的脊椎动物。在这一类群中，衍生的翼手类至少从晚侏罗世起就代表了最大的分类和生态多样性。翼手类化石记录出现于晚侏罗世早期，但它们在晚侏罗世的系统发育关系和多样性表明它们的起源将在早侏罗世中期甚至晚侏罗世。然而，翼龙的化石记录强烈偏向于特殊的Lagerstätten，至少在侏罗纪，北半球。阿根廷丘布省早侏罗世和中侏罗世的翼龙化石的发现，对我们了解翼龙的侏罗纪进化和翼手类的起源具有很大的潜力。由于在Chubut的Toarcian-Bajocian Cañadón Asfalto组中描述的唯一分类群代表了单鳍目动物（翼足类所属的分支）的近亲，并且从该组中已经知道了显示该分支特征的进一步遗骸，因此这个单位似乎可以提供关于翼足类起源的新数据。因此，本项目的目的是研究阿根廷丘布省Cañadon Asfalto组及其等效组的翼龙动物群。我们将建立该动物群的分类多样性，并分析已鉴定分类群的系统发育关系。在此基础上，我们还将进一步研究其对典型翼足蕨的生态学框架和形态进化的影响。

Pterosaurian archosaurs were the first group of vertebrates to achieve active flapping flight. Within this group, the derived pterodactyloids represent the greatest taxonomic and ecological diversity at least from the Late Jurassic onwards. Pterodactyloids appear in the fossil record in the early Late Jurassic, but their phylogenetic relationships and diversity in the Late Jurassic indicate that their origin will be found in the Middle or even late Early Jurassic. However, the fossil record of pterosaurs is strongly biased in favour of exceptional Lagerstätten and, at least in the Jurassic, the northern Hemisphere. Finds of pterosaurs from the latest Early and Middle Jurassic of the province of Chubut, Argentina, thus have a great potential to improve our understanding of the Jurassic evolution of pterosaurs and the origin of pterodactyloids. Since the only taxon described from the Toarcian-Bajocian Cañadón Asfalto Formation in Chubut represents a close relative of monofenestratans (the clade to which pterydactyloids belong), and further remains that show features of this clade are already known from that formation, it seems likely that this unit can provide new data on the origin of pterydactyloids. The objective of the present project is thus a study of the pterosaur fauna from the Cañadon Asfalto Formation and its equivalents in the Argentinean province of Chubut. We will establish the taxonomic diversity of this fauna and analyse the phylogenetic relationships of the identified taxa. Furthermore, we plan to investigate the implications for the eological framework and the morphological evolution of the typical pterydactyloid bauplan.