Sur la decouverte dans le Pleistocene inferieur de la valle de l'Omo (Ethiopie) d'une mandibule d'Australopithecien.

In 1967 Arambourg and Coppens discovered  Omo 18, the first specimen of Paranthropus aethiopicus, also known as Paraustralopithecus aethiopicus; however it's classification as a new species was initially dismissed. In 1985, when Alan Walker and Richard Leakey discovered the famous "Black Skull" (KNM-WT 17000) west of Lake Turkana in Kenya, the classification reemerged. and a new "robust" australopithecine species dating to at least 2.5 million years before present in eastern Africa, became accepted.