Drusilasaura deseadensis gen. et sp. nov., a new titanosaur (dinosauria-sauropoda), of the bajo barreal formation, upper cretaceous of north of Santa Cruz, Argentina

Abstract

A new titanosaurid from Patagonia, Argentina, is here described, Drusilasaura deseadensis gen. et sp. nov., the materials include four dorsal vertebrae, one sacral vertebra, six caudal vertebrae, left scapula, dorsal rib fragments, two haemapophyses and indeterminate fragments. The material comes from the Upper Member of the Bajo Barreal Formation (Cenomanian-Turonian), exposed in the María Aike Ranch, Santa Cruz Province, Patagonia, Argentina. The taxon shows the following character association: (i) presence in the anterior dorsal vertebrae, of two robust spinodiapophyseal laminae, one anterior and other posterior, which delimit an elongate and deep supradiapophyseal cavity; (ii) presence in the anterior dorsal vertebra of a small circumneural lamina surrounding the neural canal in posterior view; (iii) the last sacral vertebra with postspinal lamina expanded toward the neural spine apex; (iv) prespinal laminae, at least until 5°? caudal vertebra, expanded toward the neural spine apex; (v) existence in the anterior caudal vertebrae of tuberopostzygapophyseal laminae; (vi) presence of ventral foramina, at least until the 4°? caudal vertebrae; and (vii) prezygapophyseal tuberosity jointed the prespinal lamina until the 4°? caudal vertebrae. The presence of a synapomorfic character of the clade Lognkosauria suggests the probable inclusion of the Drusilasaura deseadensis gen. et sp. nov. within the clade, in tandem with Mendozasaurus neguyelap, Futalognkosaurus dukei and probably Puertasaurus reuili. © 2011 by the Sociedade Brasileira de Paleontologia.