This left mandible fragment was found in 1985 by Peter Nzuve Mutiwa from LOM 4, in similarly aged deposits from which the world's oldest known stone tools were discovered and recently published. Prior to the discovery of KNMWT 40000 this specimen had been assigned to A. afarensis however it is most likely to be additional Kenyanthropus platyops material. This left mandible has a complete third molar and a broken lower second molar. The third molar has a distinct protostylid that is not found in similar specimens of A. afarensis.
The skull of this species is KNMWT 40000. The recent discovery in Ethiopia of a third hominin species, Australopithecus deyiremeda from this same time show, us convincingly that hominin diversity extends well back in time to beyond 3.5 million years. This was not readily accepted at the time of the original Kenyanthropus discovery but additional discoveries from this important age have contributed to our understanding of this time period.
