ZAPALASAURUS BONAPARTEI, UN NUEVO DINOSAURIO SAURÓPODO DE LA FORMACIÓN LA AMARGA (CRETÁCICO INFERIOR), NOROESTE DE PATAGONIA, PROVINCIA DE NEUQUÉN, ARGENTINA

LEONARDO SALGADO, ISMAR DE SOUZA CARVALHO, Y ALBERTO GARRIDO

GEOBIOS

ELSEVIER

Lugar: Lyon; Año: 2005

0016-6995

An incomplete skeleton from Puesto Morales (Neuquén Province, Argentina) is described as a new species of sauropod, Zapalasaurus bonapartei. The unit that yielded the holotype of this dinosaur is the Piedra Parada Member of the La Amarga Formation, whose age is regarded as Barremian-lower Aptian. Several characters are interpreted as autapomorphies of Zapalasaurus bonapartei: cervical vertebrae with a lamina uniting the prezygapophysis and the zygapophyseal portion of the postzygodiapophyseal lamina, cervical vertebrae with the diapophyseal portion of the postzygodiapophyseal lamina reduced, cervical vertebrae with poorly developed spinoprezygapophyseal laminae, mid and posterior caudal vertebrae with anteroposteriorly elongated neural spines, whose anterodorsal corners are higher than their posterodorsal ones, y caudal centrum length doubles over first 20 vertebrae. Zapalasaurus bonapartei is considered as the sister group of the other diplodocoids (excluding Haplocanthosaurus). Diplodocoids were abundant in the Early Cretaceous, becoming extinct by the early Late Cretaceous. The record of Zapalasaurus bonapartei shows that, at least in the Neuquina Basin,  basal diplodocoids were more diverse than previously thought.