The Baringo (Kapthurin) ulna

Abstract The adult hominid ulna, KNM-BK 66, which was discovered in 1966 in the Kapthurin Formation, Baringo, Kenya, is described and assessed. The ulna differs from Australopithecus boisei (Omo L.40.19) and Neanderthal ulnae and from OH 36 in its gracile and slender overall appearance and in its relatively straight shaft. It also differs from modern human ulnae in having a disproportionately small coronoid process. In view of these differences and the close association of the ulna with the KNM-BK 67 mandible already attributed to Homo cf. erectus , it would seem prudent to include the Baringo ulna in the same taxon.