Image: OH 9 Homo ergaster skull side view
Cast of skull OH 9, discovered by Louis Leakey in 1960 at Olduvai Gorge in Tanzania. Its estimated to be about 1.5 million years old. The skull consists of a partial braincase with massive browridges and has a brain size of 1065cc.
- Carl Bento
- © Australian Museum
This skull shares more features with Asian Homo erectus than with other African Homo ergaster remains and is closest in size and morphology to skull Sangiran 17. This implies that either Homo erectus migrated back into Africa from Asia or that all the Homo ergaster and Homo erectus specimens should be classified as one highly variable species, rather than two.