PROSQUALODON AUSTRALIS (CETACEA: ODONTOCETI) FROM THE EARLY MIOCENE OF PATAGONIA, ARGENTINA: REDESCRIPTION AND PHYLOGENETIC ANALYSIS

Abstract

We re-describe the holotype and referred specimen of Prosqualodon australis, early Miocene of Gaiman Formation (Chubut province, Argentina), and analyse its phylogenetic position. Our study shows that this taxon is presently represented by an adult and a juvenile individual and provide the first diagnosis of the species based on the morphology of the anterior projection of the antorbital process along with plesiomorphic dental features (such as well-marked heterodont, large lateromedially compressed teeth with long crowns, reticulated enamel, and birradiculated teeth in the maxillae). The total body length of P. australis is estimated to be 2 m in the juvenile and 3 m in the adult specimen. We included for the first time this species in a phylogenetic analysis as an operational taxonomic unit itself, recovering P. australis as a stem-Odontoceti and Prosqualodon as a paraphyletic genus. The relative basal position of P. australis in the optimal trees recovered may respond to plesiomorphic skull characteristics.