Marsupials (Herpetotheriids) from the late Palaeogene of south-east Serbia

Three marsupial species are present in Palaeogene assemblages from south-eastern Serbia, Amphiperatherium minutum (Aymard, 1846), A. exile (Gervais, 1848–1852) and a species of Peratherium Aymard, 1850. These species are common in the late Eocene and early Oligocene of Western and Central Europe and their presence in South-Eastern Europe indicate that by the end of the Eocene, the eastwards dispersal of these marsupial species was already a fact. The presence of the same marsupial species in Serbia and in Western Europe is surprising, as the difference in composition between the Serbian and Western European rodent faunas indicates a limited faunal exchange between these areas in the late Eocene and early Oligocene. In marsupials, the stylar shelf of the upper molars shows a large morphological variation. A lesser-known variation is the presence of a transverse crista in the stylar shelf. These occur in various marsupial species, but so far were not known to be present in Amphiperatherium minutum. In our opinion, the large morphological variation of the stylar shelf is thus better not used to define a new species.