New remains of Andesaurus (Sauropoda-Titanosauria): contribution to the knowledge of its caudal anatomy

ALEJANDRO OTERO; JUAN CANALE; ALEJANDRO HALUZA; JORGE CALVO; LEANDRO PÉREZ; JAVIER OCHOA

San Juan

Jornada; XXII Jornadas Argentinas de Paleontología de Vertebrados; 2006

Facultad de Ciencias Exactas, Físicas y Naturales (Universidad Nacional de San Juan)

In this contribution we present new materials of the genus Andesaurus Calvo and Bonaparte. It comes from the top of Candeleros Formation (Neuquén Group) near Villa El Chocón, Neuquén province. The specimen (MMCH-Pv 47) includes a sequence of five articulate middle caudal vertebrae with haemal arches, and four posterior caudals. Each centra is amphyplatic with its ventral face showing a deep furrow, as that of the holotype. Neural spines are width and laminar and neural arches are placed a little more backwards than in other titanosaus. In anterior view haemal arches are open proximally as those present in other members of Titanosauria. In lateral view the caudal series shows variations that not correspond to that of the holotype (MUCPv-132). The holotype of Andesaurus delgadoi is deformed by smashing and compression but the new materials are much better preserved, so that allows us to study its original morphology and to improve the knowledge about the anatomy of primitive titanosaurs. A. delgadoi was collected from the middle section of Candeleros Formation, therefore this new discovery extends the temporal range of this genus, at least, up to the top of Candeleros Formation.