Extract

More than one thousand specimens representing fossil hippopotamus have been recovered from deposits in the Baringo Basin. This collection, the greater part of which consists of isolated teeth, spans a time range covering the last ten million years and contains the earliest recognizable hippo remains in the world. Comparison with other hippopotamus faunas reveals a striking conservatism until about four million years ago. Specimens from later deposits are much more numerous, with speciation and diversification in the East African forms becoming apparent. In the Baringo area this diversification is first seen in hippos from the Chemeron Formation which can be favourably compared with specimens from Kanapoi and the early levels of the Omo and East Lake Turkana. In the later Pleistocene deposits of Baringo the hippopotamus is close to the extant Hippopotamus amphibius and associated with permanent water. It is possible that the earlier levels of the Baringo Basin may hold the key to the origin of the Family Hippopotamidae, the ancestry of which is at present obscure.