OH 24
Exhibit item
Nickname: 
Twiggy
Site: 
Olduvai Gorge, Tanzania
Date of discovery: 
1968
Discovered by: 
Peter Nzube
Age: 
About 1.8 million years old
Species: 
Homo habilis

OH 24 is the oldest fossil skull found at Olduvai Gorge; besides OH 5, it is the most complete.

The cranium was found crushed flat (hence the nickname) and cemented together with a coating of limestone. Little value was placed on the find originally, but after much effort by scientist Ron Clarke, the skull was reconstructed. Despite this effort, there still is a good deal of distortion from the fossilization process. The slightly small cranial capacity (just under 600 cubic centimeters) is attributed to this distortion. The face of the individual is prognathic (projects forward under the nose: see the third photograph down), as in other H. habilis individuals, but not quite to the extent of the earlier Australopithecus species. This specimen manifests the larger brain size and the reduction of facial size typical of the evolution of early Homo.

The individual's third molars had erupted, so we know that Twiggy was an adult at death. Yet the molars show no sign of wear (the points on the crowns of her teeth are still sharp, and show little sign of abrasion by rough food matter), indicating that that this individual probably died soon after their eruption.

Image of OH 24 skull, 3/4 view