This skull didn’t start out black – it was white, like all other bones in living animals. KNM-WT 17000 or the ’Black Skull’ only got its dramatic dark color after millions of years of sitting in a manganese-rich soil and absorbing minerals as it fossilized.

This nearly complete fossilized cranium has a face that projects far outward from the forehead, widely flaring zygomatic arches, and the largest sagittal crest of any early human. Though some of the individual’s front teeth fell out and others were broken off after death, molar and premolar roots in the jaw indicate that this early human would have also had massive cheek teeth; all of these features are adaptations for heavy chewing.

Because of the sagittal crest and the skull’s small cranial capacity (410cc), researchers originally classified the ’Black Skull’ as Paranthropus boisei - but further comparison showed more similarities to Australopithecus afarensis. This mosaic of features led scientists to assign the specimen to a new species: Paranthropus aethiopicus.

The ’Black Skull’ is the only known adult skull of Paranthropus aethiopicus.