Australopithecus

Australopithecus (/ˌɒstrələˈpɪθɪkəs/, OS-trə-lə-PITH-i-kəs;[1] from Latin australis 'southern', and Greek πίθηκος (pithekos) 'ape'; singular: australopith) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genera Homo (which includes modern humans), Paranthropus, and Kenyanthropus evolved from Australopithecus. Australopithecus is a member of the subtribe Australopithecina,[2][3] which also includes Ardipithecus,[4] though the term "australopithecine" is sometimes used to refer only to members of Australopithecus. Species include A. garhi, A. africanus, A. sediba, A. afarensis, A. anamensis, A. bahrelghazali and A. deyiremeda. Debate exists as to whether some Australopithecus species should be reclassified into new genera, or if Paranthropus and Kenyanthropus are synonymous with Australopithecus, in part because of the taxonomic inconsistency.[5][6] The earliest known member of the genus, A. anamensis, existed in eastern Africa around 4.2 million years ago. Australopithecus fossils become more widely dispersed throughout eastern and southern Africa (the Chadian A. bahrelghazali indicates the genus was much more widespread than the fossil record suggests), before eventually becoming extinct 1.9 million years ago (or 1.2 to 0.6 million years ago if Paranthropus is included). While none of the groups normally directly assigned to this group survived, Australopithecus is not literally extinct (in the sense of having no living descendants), as the genus Homo emerged from an Australopithecus species[5][7][8][9][10] at some time between 3 and 2 million years ago.[11] Australopithecus possessed two of three duplicated genes derived from SRGAP2 roughly 3.4 and 2.4 million years ago (SRGAP2B and SRGAP2C), the second of which contributed to the increase in number and migration of neurons in the human brain.[12][13] Significant changes to the hand first appear in the fossil record of later A. afarensis about 3 million years ago (fingers shortened relative to thumb and changes to the joints between the index finger and the trapezium and capitate).[14]