title: New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya.
abstract: Nine hominid dental, cranial and postcranial specimens from Kanapoi, Kenya, and 12 specimens from Allia Bay, Kenya, are described here as a new species of Australopithecus dating from between about 3.9 million and 4.2 million years ago. The mosaic of primitive and derived features shows this species to be a possible ancestor to Australopithecus afarensis and suggests that Ardipithecus ramidus is a sister species to this and all later hominids. A tibia establishes that hominids were bipedal at least half a million years before the previous earliest evidence showed.
authors.affiliation: National Museums of Kenya, Nairobi.
authors.forename: M G
authors.initials: MG
authors.lastname: Leakey
authors.forename: C S
authors.initials: CS
authors.lastname: Feibel
authors.forename: I
authors.initials: I
authors.lastname: McDougall
authors.forename: A
authors.initials: A
authors.lastname: Walker
mesh_terms: D000818:Animals; D005580:Fossils; D015186:Hominidae / Q000145:classification; D006801:Humans; D007630:Kenya; D008322:Mammals; D008334:Mandible; D012886:Skull; D014070:Tooth