the oldest robust australopithecine discovered to date. The prominence of the crest appears to have been an adaptation for the P. aethiopicus' heavy chewing, and the Black Skull's cheek teeth are correspondingly large. Smaller sagittal crests are also present on the skulls of other Paranthropines, including Paranthropus boisei and Paranthropus robustus.

The shrinking of the sagittal crest in human ancestors was widely attributed to a growing brain and shrinking teeth. However, it was discovered in 2004 by a group of researchers led by