The Interatheriinae from the Late Oligocene of Mendoza (Argentina), with comments on some Deseadan Interatheriidae

This contribution discusses the interatheriids from Quebrada Fiera, a Late Oligocene locality in the south of Mendoza Province. In addition, the taxonomic status of the Deseadan interatheres Plagiarthrus clivus, Argyrohyrax proavus, Argyrohyrax proavunculus, ? Argyrohyrax acuticostatus, Progaleopithecus fissurelatus, Progaleopithecus tournoueri, and Notohyrax conicus is discussed. We recognise in Quebrada Fiera A. proavus and Progaleopithecus sp. A possible third taxon is represented by one specimen that shows a combination of features that do not permit accurate assignment. These new remains, in combination with a systematic study of Deseadan interatheres, allow for a better definition of each recognised taxon, extended diagnoses, and clarification of some long-standing taxonomic misconceptions. Indeed, the priority of A. proavus over P. clivus is established, and the latter is proposed as a nomen dubium. Associated deciduous and permanent dentition and some limb bones provide new data on the ontogenetic variation and postcranial morphology of Argyrohyrax. Phylogenetic analysis supports the taxonomic determinations and places A. proavus in a basal position with respect to Archaeophylus or Progaleopithecus. Documented fossil records of Argyrohyrax and Progaleopithecus in Mendoza extend the known range to middle latitudes in central west Argentina; these taxa expand the list of mammals from Quebrada Fiera with Patagonian affinities.