Revision of the European species of Prosantorhinus (Mammalia, Perissodactyla, Rhinocerotidae)

Abstract

t is not size that distinguishes the genus Prosantorhinus from Diaceratherium , but the following characters: a concave dorsal skull profile with upslanting nasals and narrowing on the distal side of the last upper molar. Using these characters, in addition to the type species Prosantorhinus germanicus (), the following species can be added to the genus: Prosantorhinus douvillei () (, .), from the Early and Middle Miocene (MN 3–5) of Western Europe, Prosantorhinus laubei from MN 3 of northern Bohemia, Prosantorhinus aurelianensis () from MN 3–4a of Western Europe, and with some reservation “Rhinoceros” tagicus (), an enigmatic species from the Early Miocene (MN 3) of Portugal, known only by its upper cheek teeth. At the beginning of MN 3 (), the metapodials of Prosantorhinus aurelianensis were considerably more robust than those of the latest Diaceratherium species (Laugnac, MN 2b) (.) Within the genus shortening of the distal limb segments and narrowing of the distal side of M3 increased with time. The metapodials of Prosantorhinus laubei are less robust but of medium length, in contrast to the Middle Miocene (MN 5) Prosantorhinus germanicus in which they are extremely shortened. No transitional species or co-occurrence of Diaceratherium and Prosantorhinus are known.