Rhinocerotidae (Mammalia, Perissodactyla) from the chrono-stratigraphically constrained Pleistocene deposits of the urban area of Rome (Central Italy)

Abstract

In the present paper we provide a revision of the Pleistocene Rhinocerotidae remains collected so far in the sedimentary deposits of the urban area of Rome. Five Pleistocene species have been identified: Stephanorhinus etruscus (Falconer), Stephanorhinus hundsheimensis (Toula), Stephanorhinus hemitoechus (Falconer), Stephanorhinus kirchbergensis (Jäger), and Coelodonta antiquitatis (Blumenbach). By establishing correlations of the sedimentary sections hosting the fossil remains with the geochronologically-constrained, astronomically-forced aggradational successions of the Paleo-Tiber River, we frame the fossil remains within a detailed chronostratigraphic scheme with no equivalent in the previous literature. This approach leads to new considerations on the occurrences and paleobiogeography of the recovered species. Based on the studied material, the last occurrence of S. etruscus in Italy is here referred to a timespan between 0.86 and 0.82 Ma, thus suggesting a long persistence of this species. Recalibration of the considered deposits enabled us to refer the first evidence of S. hundsheimensis in Italy to approximately 0.8 Ma (Ponte Milvio gravels and sands; urban area of Rome). In the Roman area, specimens referred to S. hundsheimensis are coeval with relatively smaller and slender remains of an undefined rhinoceros species. S. hemitoechus is recorded in fossiliferous deposits earlier than 0.4 Ma and its persistence in the studied area is reported at least until 0.19 Ma. S. kirchbergensis occurs for the first time in Italy at ca. 0.56–0.5 Ma (Tor di Quinto deposit; urban area of Rome) and persists in the considered area until 0.37–0.29 Ma. C. antiquitatis is here reported for the first time within the Roman area, so adding a new record of this species in Italy. Unfortunately, the exact locality in which the specimens were collected is unknown, preventing from precise chronostratigraphic assessment.