El registro más antiguo de Panochthus (Xenarthra, Glyptodontidae)

Abstract

Panochthus is one of the largest sized and most frequently recorded genera of Pleistocene South American Glyptodontidae. A recent taxonomic revision shows that the genus includes six species: P. intermedius and P. subintermedius (early Pleistocene-middle Pleistocene), P. tuberculatus and P. frenzelianus (middle Pleistocene-late Pleistocene), whereas P. greslebini and P. jaguaribensis only can be referred to the Pleistocene sensu lato. In this contribution the oldest record of the genus Panochthus (MMP 5171) is presented and described. The remains came from the late Pliocene (Playa Los lobos Aloformation, Chapadmalal Formation; Chapadmalalan; Paraglyptodon chapalmalensis Biozone) of the Mar del Plata, Buenos Aires province, Argentina. The material is represented by a considerable fragment of dorsal carapace and some associated osteoderms, which are assignable to an indeterminate species of Panochthus. One of the most significant characters in the exposed surface of the osteoderms is the presence of a clear "reticular" pattern, a character only observed in Panochthus. From a biostratigraphic viewpoint, it is remarkable the absence of records of Panochthus in the Marplatan Age/Stage (late Pliocene-early Pleistocene).