An articulated titanosaur from Patagonia (Argentina): new evidence of neosauropod pedal evolution

GONZÁLEZ RIGA, BERNARDO J.; CALVO, JORGE O.; PORFIRI, JUAN

PALAEOWORLD

ELSEVIER

Lugar: Amsterdam; Año: 2008 p. 33 - 40

1871-174X

Most titanosaur dinosaurs are represented by incomplete skeletal elements lacking articulated pes. An exceptionally preserved specimen from the Late Campanian-Early Maastrichtian strata of Patagonia (Argentina) provides new data on pedal morphology and the evolutionary trends of these huge dinosaurs. This finding is one of the few articulated titanosaur pes known in the world, and shows a phalangeal formula of 2-2-2-2-0. The first three digits posses sickle-shaped claws and the articular faces of ungual phalanges suggesting mobility in horizontal and vertical planes. An comparative analysis of available record  suggests that titanosaurs had a progressive reduction of size and number of pedal phalanges in digits III and IV during the Late Cretaceous. Key word: Pes morphology, Sauropoda, Titanosauria, Cretaceous, Patagonia, Argentina.