"Of the extant lineages of s, tapirs have the poorest and least understood fossil record. Both molecular and morphological data agree that the tapirs and rhinoceroses are more closely related to each other than to horses ..., and the superfamilies and are combined as Ceratomorpha. ... While the fossil record of horses and rhinoceroses is notable for its diversity and illustration of evolutionary trends, tapirs and their fossil relatives are more notable for their conservatism. Both living and fossil tapirs typically inhabit or have inhabited warm, closed canopy forests, not unlike the earliest perissodactyls. However, tapir evolution shows many of the same trends as that of horses and rhinos, including increases in body size and premolars that increasingly resemble molars (i.e. premolar molarisation)."