This cranium of a young adult has one of the smallest brain sizes known in Homo erectus–similar to brain size seen in some Homo habilis  fossils, but it has features more similar to other Homo erectus crania. It was found in an area of northern Kenya where younger fossils of Homo habilis have been found, demonstrating that these two species existed at the same time, rather than H. habilis being ancestral to H. erectus.