Proposal by Richard Leakey that four hominid species
may have lived concurrently in East Africa 3-1 mya
: one was smalljawed but large-brained (e.g. Homo), a second was megadont but small-brained (e.g. Australopithecus ( Paranthropus) boisei), a third was a gracile australopithecine
(e.g. KNM-ER 1813), and a fourth was like KNM-ER 1482.