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

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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.