Crocodylomorph osteoderms morphology from the Paleontological Site of Peirópolis (Bauru Basin, Upper Cretaceous)

Abstract

Osteoderms are dermal bony plates situated over the epiderm and covered by queratin layer. Until now are recognized at the Paleontological Site of Peirópolis three distinct crocodylomorph species, the Peirosauridae Peirosaurus termini Price, 1955 and Uberabasuchus terrificus Carvalho; Ribeiro & Ávilla, 2004 and the Trematochampsidae Itasuchus jesuinoi Price, 1955. The peirosaurids have nostrils frontally positioned within the skull and are regarded as terrestrial crocodylomorphs. The trematochampsids differently from the peirosaurids have the nostrils positioned at the dorsal portion of the skull, similar to the extant crocodiles with aquatic habits. The osteoderms morphological analysis of P. tormini, U. terrificus and I. jesuinoi corroborate, with the cranial evidences, for the terrestrial or aquatic lifestyle of these animals.