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

LUCAS FIORELLI; JORGE O. CALVO

ARQUIVOS DO MUSEU NACIONAL

MUSEU NACIONAL

Lugar: Río de Janeiro; Año: 2007 vol. 65 p. 417 - 459

0365-4508

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, Zosuchus, and Artzosuchus from the Upper Cretaceous of Mongolia; Tagarosuchus from Lower Cretaceous of Southern Siberia; Edentosuchus, Sichuanosuchus, and Shantungosuchus from Lower Cretaceous of China. We report a new basal crocodyliform taxon, Neuquensuchus universitas gen.nov., sp.nov., from Neuquén Province, Argentina, belonging to Bajo de la Carpa Formation, representing the first and only “protosuchian” from the Cretaceous of Gondwana. The articulated and fragmentary materials belonged to a willowy, slender species, with very long and thin extremities. As in Shantungosuchus, the cervical centers are lengthened, with prominent ventral keel and well developed anteroventral parapophyses. As in 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 other non-derivated crocodyliforms. Besides representing the first Cretaceous “protosuchian” of Gondwana, the occurrence of these outside of Asia and Europe during the Cretaceous offers new evidence of pre-Albian dispersion between Gondwana and Central Asia through Europe.