The skull of Stephanorhinus hemitoechus (Mammalia, Rhinocerotidae) from the Middle Pleistocene of Campagna Romana (Rome, central Italy): biochronological and paleobiogeographic implications

A fragmentary rhinoceros skull from the "Campagna Romana" was analysed. The results of morphometrical and morphological analysis identify the skull as Stephanorhinus hemitoechus. The petrography and geochemistry of the volcanoclastic sediments containing the rhinoceros skull indicate that its geographic provenance is the northern area of Rome (between the Tiber River and the southern area of the Sabatini Volcanic District). The textural and geochemical features of white pumice indicate that the volcanoclastic sediments were deposited at ca 500 ka during the MIS13. A revision of the earliest records of S. hemitoechus in Europe reveals that the skull from Campagna Romana is the earliest record of the species. The time and spatial collocation of this occurrence postdate the diffusion of S. hemitoechus in the Mediterranean Basin, most likely due to the favourable climate. Successively, the species becomes common in the rest of western and northern Europe and reached its maximal geographic extension during MIS5.