"The Black Skull" (KNM-WT 17000), Australopithecus aethiopicus
Discovered by Alan Walker in 1985 near West Turkana in Kenya. Estimated age is 2.5 million years. This find is an intact, almost complete cranium. The brain size is very small for a hominid, about 410 cc, and the skull has a puzzling mixture of primitive and advanced features.
Credit: photo from the In Hand Museum; reproduced by kind permission.