The first record of the genus Prosantorhinus (Perissodactyla: Rhinocerotidae) of East Asia

Abstract

Abstract Prosantorhinus is a genus of small extinct teleoceratine rhinoceroses with shortened limb bones, widely distributed in Europe. However, the Asian evolution of the teleoceratine Prosantorhinus has remained unclear because of a scarcity of fossil records of the genus. Here, we report the first record of Prosantorhinus in East Asia from the Middle Miocene of Tongxin, Ningxia. The new specimen is characterized by a concave dorsal skull profile and elevated nasals; short and stout nasal bones with drooping margins on both sides; the thickened, enlarged, and roughened nasal extremity supporting a small horn; the semi-molarized upper premolars with a lingual bridge between the protocone and hypocone; the metaloph constriction present on P2–4; the protocone equal to the hypocone on P2; the crista present on P3; and the cement on the cheek teeth developed. With all the morphological evidence considered, we establish a new species, Prosantorhinus yei sp. nov.. A phylogenetic analysis based on 282 morphological characters scored for 36 taxa reveals that Prosantorhinus yei sp. nov. is a relatively derived taxon in the genus. We hypothesize that Prosantorhinus yei sp. nov. lived in relatively moist environments.