THE FIRST PROTOSUCHIAN (ARCHOSAURIA: CROCODYLIFORMES) FROM THE CRETACEOUS OF GONDWANA

LUCAS FIORELLI; JORGE CALVO

Río de Janeiro, Brasil

Congreso; II Congreso Latinoamericano de Paleontología de Vertebrados; 2005

Museu Nacional

The remains of protosuchians from the Cretaceous come, to exception of “Las Hoyas crocodyliform” from the Lower Cretaceous of Spain, exclusively of Central Asia: Zaraasuchus, Gobiosuchus and Zosuchus from the Upper Cretaceous of Mongolia and Edentosuchus, Sichuanosuchus and Shantungosuchus from Lower Cretaceous of China. We report a new form of basal crocodyliformes from the Cretaceous of Neuquén province, Argentina, belonging to Bajo de la Carpa Formation, representing the first and only “protosuchian” of Gondwana. The articulated and fragmentary materials correspond to a willowy, slender species, with very long and thin extremities. As in Shantungosuchus, the cervical center is lengthened, with prominent ventral keel and well developed anteroventral parapophyses. As the basal crocodylomorphs, it possesses two sacral vertebrae. Also, a much enlarged scapular blade, with well developed acromial ridge and the posterior edge similar to Sichuanosuchus. The pronounced deltopectoral crest in the complete humerus is equivalent to Sichuanosuchus and as this a circular, elongated and thin shaft with the medial condyle longer than the lateral one. Also, the complete ulna and radius is similar in their proportions to Sichuanosuchus. As this, the pubis is lengthened, very thin in the half section and not very expanded distally. The femur, tibia and fibula are elongated and similar to a basal form of China, and others crocodylomorphs. Besides representing the first Cretaceous "protosuchian" of Gondwana, the occurrence of these outside of Asia and Europe during the Cretaceous, offers new evidence of the contact happened in  pre-Albian times between Gondwana and Central Asia through Europe.