Paranthropus aethiopicus

Paranthropus aethiopicus is an extinct species of robust australopithecine from the Late Pliocene to Early Pleistocene of East Africa about 2.7–2.3 million years ago. However, it is much debated whether or not Paranthropus is an invalid grouping and is synonymous with Australopithecus, so the species is also often classified as Australopithecus aethiopicus. Whatever the case, it is considered to have been the ancestor of the much more robust P. boisei. It is debated if P. aethiopicus should be subsumed under P. boisei, and the terms P. boisei sensu lato ("in the broad sense") and P. boisei sensu stricto ("in the strict sense") can be used to respectively include and exclude P. aethiopicus from P. boisei.

Like other Paranthropus, P. aethiopicus had a tall face, thick palate, and especially enlarged cheek teeth. However, likely due to its archaicness, it also diverges from other Paranthropus, with some aspects resembling the much earlier A. afarensis. P. aethiopicus is known primarily by the skull KNM WT 17000 from West Turkana, Kenya, as well as some jawbones from Koobi Fora; the Shungura Formation, Ethiopia; and Laetoli, Tanzania. These locations featured bushland to open woodland landscapes with edaphic (water-logged) grasslands.