A new peirosaurid (Crocodilyformes) from the Late Cretaceous (Turonian–Coniacian) of Patagonia, Argentina

Abstract

Peirosauridae is composed of mid- to large-sized terrestrial mesoeucrododylian crocodyliforms distributed throughout Gondwanan landmasses. Here we describe a new peirosaurid that comes from the upper levels of the Portezuelo Formation (Turonian–Coniacian, Upper Cretaceous) from Loma de la Lata, Neuquén Province, Argentina. This specimen consists of some associated bones belonging to a single individual. In order to facilitate comparisons, we recognise two different peirosaurid morphotypes based on skull shape: broad- and narrow-snouted taxa. The new taxon may be related to broad-snouted taxa, especially Gasparinisuchus peirosauroides. The new taxon here reported has strong heterodont dentition when compared with other peirosaurids. As in related forms, the fourth dentary tooth is caniniform, very large, acute and transversely compressed (much more than other peirosaurids), and the anterior dentary teeth have less globular, sharp serrated crowns. Large interalveolar spaces are present between both mandibular and maxillary teeth, a trait only observed on the new taxon. With this addition, we elevate the number of Patagonian peirosaurids to four. Moreover, it represents together with Lomasuchus palpebrosus the second peirosaurid species described for the Portezuelo Formation.