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 <i>Plagiarthrus clivus</i>, <i>Argyrohyrax proavus</i>, <i>Argyrohyrax proavunculus</i>, ?<i>Argyrohyrax acuticostatus</i>, <i>Progaleopithecus fissurelatus</i>, <i>Progaleopithecus tournoueri</i>, and <i>Notohyrax conicus</i> is discussed. We recognise in Quebrada Fiera <i>A. proavus</i> and <i>Progaleopithecus</i> 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 <i>A. proavus</i> over <i>P. clivus</i> is established, and the latter is proposed as a <i>nomen dubium</i>. Associated deciduous and permanent dentition and some limb bones provide new data on the ontogenetic variation and postcranial morphology of <i>Argyrohyrax</i>. Phylogenetic analysis supports the taxonomic determinations and places <i>A. proavus</i> in a basal position with respect to <i>Archaeophylus</i> or <i>Progaleopithecus</i>. Documented fossil records of <i>Argyrohyrax</i> and <i>Progaleopithecus</i> 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.