Oldest azhdarchid (Pterosauria) record from South America

Resumen

Azhdarchid pterosaurs in South America were hitherto represented by two taxa coming from Coniacian-Santonian and Maastrichtian beds, of the Mendoza and Río Negro provinces, respectively, in Argentina. Here we report an incomplete pterosaur cervical vertebra from Cenomanian beds exposed at the east shore of Ezequiel Ramos Mexía Reservoir at the Río Negro Province (Patagonia, Argentina). The cervical vertebra is referred to Azhdarchidae by the presence of a notoriously slender centrum being sub-circular in cross-section at its mid-length, with well-developed postexapophyses, and extremely reduced neural spine. The recovered specimen represents a pterosaur smaller in size than the previously found azhdarchids in Patagonia, and constitutes the oldest record for the clade in the South American continent. Thus, it constitutes an important addition to the knowledge of the diversity of the clade in Patagonia during the Cretaceous.