ABELISAURID (DINOSAURIA,THEROPODA) REMAINS FROM THE CANDELEROS FORMATION CENOMANIAN, NEUQUÉN PROVINCE, ARGENTINA.

CANALE, JUAN IGNACIO; HALUZA, ALEJANDRO

Buenos Aires

Jornada; XXVI Jornadas Argentinas de Paleontología de Vertebrados; 2012

The abelisaurids are the best-represented carnivorous dinosaurs in Cretaceous rocks of Argentina. In particular, the beds of the Neuquén Group have yielded several abelisaurid species. Here we report on the discovery of a partial pelvis and a distal half of metatarsal II of an abelisaurid from the Candeleros Formation at Barda Atravesada area, 20 km at south of Villa El Chocón. The pelvic elements include a partial right ilium, complete right pubis fused with the distal part of the left one, and fragments of the proximal portion of right ischium. These elements shows ceratosaurian traits (e.g., supraacetabular crest and brevis shelf connected by a crest, pubic boot dorsally concave, pubis with obturator foramen enclosed by bone) as well as abelisauroid characteristics (e.g., long and low ilium, metatarsal II transversely reduced at midshaft). The dorsal border of ilium is straight, as in Carnotaurus and Aucasaurus, but diferent from Skorpiovenator in which this margin is curved. Degree of fusion of the pelvic elements suggests a mature individual around 3 meters long, thus constituting a small to medium sized abelisaurid. Two other abelisaurids are known from the Candeleros Formation: Ekrixinatosaurus novasi (one of the largest abelisaurids, reaching 10-11 meters long) and a yet undescribed, mid-sized (5 meters) form from Aguada Pichana locality, NW Neuquén Province, both represented by pelvic elements. An integrative comparative study of abelisaurid pelves is required to improve the knowledge on the morphological variation among this group of theropods.