THE OSTEOLOGY OF CHUBUTISAURUS INSIGNIS DEL CORRO, 1975 (DINOSAURIA:

CARBALLIDO, JOSÉ LUIS; POL, DIEGO; CERDA, IGNACIO; SALGADO, LEONARDO

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2011 vol. 31 p. 93 - 110

0272-4634

Titanosauriform sauropods were one of the most widely distributed groups of dinosaurs during the Creta- ceous. In contrast to most derived forms from the Upper Cretaceous, the most basal taxa of the group are poorly known. Thus, studies on these forms are of special interest for understanding the origin and early evolution of Titanosauria. Chubuti- saurus insignis del Corro, 1975, is known from postcranial remains found in the Bayo Overo Member of the Cerro Barcino Formation (Chubut Group), which is commonly regarded as Aptian?Cenomanian in age. Phylogenetic analyses that include Chubutisaurus recovered this taxon as the sister group to Titanosauria. Nevertheless, most published studies have not in- cluded this taxon, probably due to its brief description and fragmentary remains. Fieldwork conducted in the quarry where the holotype was found yielded new materials that are regarded as part of the same specimen. These new materials, together with additional undescribed, and briefly described elements, originally collected by G. del Corro, are described here. The new information allows the recognition of a more extensive diagnosis of this taxon. The phylogenetic analysis presented here resolves Chubutisaurus as the most basal somphospondylian.