By 2.7 million years ago, a new lineage
of early humans had evolved in East Africa. Paranthropus aethiopicus
was originally proposed in 1967 by a team of French paleontologists to describe
a partial mandible (Omo 18) that was thought to differ enough from the mandibles
of the early human species known at that time.
This naming of a new species was generally dismissed; many paleoanthropologists
thought it premature to name a new species on the basis of a single incomplete
mandible. In 1985, when Alan Walker and Richard Leakey discovered the
famous "black skull" west of Lake Turkana in Kenya, the classification
reemerged. With its mixture of derived and primitive traits, KNM WT 17000
validated, in the eyes of many researchers, the recognition of a new "robust"
species dating to at least 2.5 million years ago in eastern Africa. The
issue was debated, but today there is general consensus that there was
a distinct robust species, Paranthropus aethiopicus, living in
eastern Africa 2.5 million years ago.
The exact phylogeny of P. aethiopicus is still not fully understood.
It is thought to have descended from the earlier A. afarensis,
and to be ancestral to P. boisei. However, go to the robust
forms page to learn more about the current debate concerning this
interesting branch of the human tree.