The Palaeotheriidae (Equoidea, Perissodactyla, Mammalia) from the Eocene fauna of Aumelas (Hérault department, France)

The rich vertebrate fauna of Aumelas has from decades been the subject of several partial publications, which led to assign it an age close to the MP 13 reference level in the biochronological scale of Western European mammals; but it is still partially unpublished and this paper is part of a general review of the fauna. With regard to equoid perissodactyls, five taxa have been distinguished, to be assigned to the “Pachynolophinae” to the exclusion of any Palaeotheriinae. Two leading species appear in this ensemble: Propalaeotherium sudrei Remy, Krasovec & Marandat, 2016 and Pachynolophus ruscassierensis n. sp. The three other taxa are less documented, which prevents a specific determination, Pachynolophus sp., Propalaeotherium cf. gaudryi (Lemoine, 1878) and Lophiotherium sp. All of these species display relatively archaic features as highlighted by a cladistic analysis. Such a conclusion challenges the hitherto prevailing consensus on the dating of the fauna, in the sense of an older biochronological age. This discrepancy will be discussed in a subsequent synthetic work, in conjunction with specialists of all mammal and reptile orders represented in the locality.