New ctenochasmatid pterosaur record for Gondwana: discovery in the Lower Cretaceous continental deposits of the Atacama Desert, northern Chile

Abstract

New pterosaur remains from Cerro La Isla, Quebrada Monardes Formation (Lower Cretaceous), Northern Chile, are described. The material comprises mandibular remains preserving dental bases and two vertebrae of the mid cervical series. The morphology and arrangement of the dental bases show a similar pattern to that observed in European and Chinese ctenochasmatids, but can be distinguished from those other South American ctenochasmatids reported from Argentina and Uruguay. The new vertebrae share certain characteristics with the mid cervical vertebrae of ctenochasmatids, such as very elongated centra with low neural arches, low and elongated neural spines, the presence of postexapophyses and a pair of oval pneumatic foramina on the lateral surfaces of the centra. Although most of these features are shared with the mid cervical vertebrae of azhdarchid pterosaurs, the lower integration of the neural arch, which does not acquire a tubular morphology in the mid-point of the vertebral centrum, together with the presence of oval pneumatic foramina, are characteristics that allow the referral of both vertebrae to the Ctenochasmatidae. The vertebral, mandibular and rostral remains from Cerro La Isla suggest the presence of a previously unknown ctenochasmatid pterosaur, distinct from Pterodaustro, the only other South American taxon.