| Abstract: | Three genera and six species of extinct African Plio-Pleistocene Colobinae are discussed. One new genus, Rhinocolobus and three new species, R. turkanaensis, Cercopithecoides kimeui and Paracolobus mutiwa are named. These colobines show a diversity in postcranial and dental morphology not seen among extant species. Rhinocolobus was most similar to extant Colobus in postcranial morphology and had similar high-cusped shearing teeth. Cercopithecoides shows a number of postcranial skeletal features typical of terrestrial cercopithecid species and has lower cusped teeth. Paracolobus, while generally more similar to Rhinocolobus than to Cercopithecoides, is intermediate in some features of its postcranial morphology. The distribution of the various taxa among East and South African sites with different palaeoenvironments is generally consistent with the morphological interpretation. With the exception of Cercopithecoides kimeui, which persisted a little longer, these large colobines disappear from the fossil record about 1.8 million years ago. Their disappearance coincides with an interval of increasing aridity documented at Olduvai Gorge, the Omo Valley, and East Turkana. |
