Rhinocerotidae (Mammalia, Perissodactyla) from the middle pleistocene site of ponte milvio, central Italy

Three rhinoceros species have been identified at Ponte Milvio: Stephanorhinus hundsheimensis (Toula, 1902), Stephanorhinus hemitoechus (Falconer, 1859) and Stephanorhinus kirchbergensis (Jäger, 1839). Remains ascribed to S. hundsheimensis were collected in gravels and sands deposits. They show morphological and morphometric affinities with the small-sized populations of the latest Early Pleistocene from Vallonnet. The occurrence of these small-sized specimens suggests the presence of a faunal assemblage chronologically related with the Early-Middle Pleistocene transition. The remains of S. hemitoechus and S. kirchbergensis were collected in volcanoclastic deposits. The specimens ascribed to S. hemitoechus show morphometric characters close to the small-sized specimens of the latest Middle Pleistocene. Moreover, S. kirchbergensis seems to be common in Italy during the late Middle Pleistocene and it has never been collected with certainty from Late Pleistocene sites. The co-occurrence of S. kirchbergensis and the small-sized S. hemitoechus suggests the presence of a faunal assemblage chronologically referable to a time span between MIS10 and MIS8