Australopithecus aethiopicus skull, KNM-WT 17000 (2.5 million years).
The Australopithecus aethiopicus Skull KNM-WT 17000 was discovered by A. Walker in 1985 on the west shore of Lake Turkana in northern Kenya. It was described by Walker, Leakey, Harris and Brown in Nature in 1986. The skull is commonly referred to as the "Black Skull" due to its blue-black colour. Although not considered on a direct line to humans, it gives insights into early hominid evolution. Although it shares many primitive features with A. afarensis (e.g., projecting face, small cranial capacity of 410cm3), it also has features typical of australopithecine species, e.g. projecting face, large sagittal crest and jaws, and expanded cheek teeth. Given that it seems to fall between A. afarensis and A. boisei, it was given its own species name.