Ancylotherium pentelicum (Mammalia, Chalicotheriidae) from the late Miocene of Kerassia (Greece) and remarks on its intraspecific variability

The first detailed description of Ancylotherium pentelicum (Gaudry and Lartct, 1856) from the late Miocene (Turolian) of Kerassia (Greece) is provided based on three metapodial elements. Potential intraspecific variability of this species in the Eastern Mediterranean has been previously discussed, but no decisive conclusions could be drawn. The present comparison of metapodial elements of A. pentelicum from Kerassia, Pikermi, Samos (Greece), Pinaryaka, Salihpasalar (Turkey), Kiro Kuchuk (North Macedonia), and Hadjidimovo (Bulgaria) provides evidence for the existence of notable intraspecific variation in both the morphology and especially the size of the species. The morphological differences in the shape and occurrence of some metapodial articular facets are probably associated with the anticipated individual variability and not with sexual dimorphism. On the other hand, the notable metrical variability observed among metapodials of A. pentelicum may be indicative of sexual dimorphism, as has been previously documented in other chalicotheriids.