The first record of sauropod dinosaurs from Antarctica

CERDA, I.; PAULINA CARABAJAL, A.; SALGADO, L.; CORIA, R. A.; MOLY, J.

Las Vegas

Congreso; Society of Vertebrate Paleontology annual meeting; 2011

University of Nevada

Sauropods were one of the most widely distributed group of dinosaurs for most of theMesozoic Era, although this clade has not been previously recorded in Antarctica. Here wereport the first record of a sauropod dinosaur from Antarctica, represented by an incompletecaudal vertebra from the Late Cretaceous of the James Ross Island (Antarctic Peninsula).The vertebra was collected from marine sediments assigned to the Gamma Member of theSanta Marta Formation (Campanian), constituted mainly by fine-grained to mid-size grainedsandstones. The specimen consists of a strongly procoelous middle caudal centrum lackingthe neural arch. The centrum length (excluding the posterior ball) is 170 mm and its heightis 105 mm. There is no pleurocoels, and a sagittal fracture has exposed the internal bonestructure, which is not pneumatized. The morphology and size of the specimen allow it to beidentified as a caudal vertebra of a derived sauropod dinosaur. The anterior position of theneural arch indicates referral to Titanosauriformes. The procoely of the middle caudal vertebra has been proposed to have a diagnostic feature of lithostrotian titanosaurs. The biogeographical history of sauropods and the interrelationships amongst titanosaurs from southern landmasses remain obscure and controversial. The specimen is notable for representing the first Antarctic sauropod record, but also the most southern record of the clade, adding new data in the process of resolving the affinities of South American titanosaurs and the understanding of Gondwanan paleobiogeography.