UN NUEVO SAUROPODO DICRAEOSAURIDAE, AMARGASAURUS CAZAUI GEN. ET SP. NOV., DE LA FORMACION LA AMARGA, NEOCOMIANO DE LA PROVINCIA DEL NEUQUEN, ARGENTINA

The material is represented by the basicranial and temporal regions of the skull and most of the postcranium. The comparative discussion of this new species suggests it is more derived than Dicraeosaurus hansemanni from the Late Jurassic Tendaguru beds, in the more elongate and pronounced bifurcation of the presacral vertebrae, and in the longer basipterygoid processes. The comparison of the genera Dicraeosaurus-Amargasaurus with other clades of sauropods, in particular with Diplodocidae, suggests they correspond to a family of their own: Dicraeosauridae, which is more derived than and with significant differences to Diplodocidae.