Australopithecus

Australopithecus Temporal range: Zanclean – Gelasian, 4.5–1.9/1.2 mya PreꞒ Ꞓ O S D C P T J K Pg N ↓
Mrs. Ples, an Australopithecus africanus specimen
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Hominidae
Subfamily:	Homininae
Tribe:	Hominini
Subtribe:	Australopithecina
Genus:	†Australopithecus R.A. Dart, 1925
Type species
†Australopithecus africanus Dart, 1925
Species
†A. afarensis †A. anamensis †A. africanus †A. bahrelghazali (= A. afarensis?) †A. deyiremeda †A. garhi †A. prometheus (= A. africanus?) †A. sediba Classically excluded but cladistically included: †Paranthropus †Kenyanthropus Homo

Australopithecus (/ˌɒstrələˈpɪθɪkəs, -loʊ-/, OS-trə-lə-PITH-i-kəs, -⁠loh-;^[1] or (/ɒsˌtrələpɪˈθiːkəs/, os-TRA-lə-pi-THEE-kəs^[2] from Latin australis 'southern' and Ancient Greek πίθηκος (pithekos) 'ape'^[3]) is a genus of early hominins that existed in Africa during the Pliocene and Early Pleistocene. The genera Homo (which includes modern humans), Paranthropus, and Kenyanthropus evolved from some Australopithecus species. Australopithecus is a member of the subtribe Australopithecina,^[4][5] which sometimes also includes Ardipithecus,^[6] 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.^[7][8]

Furthermore, because e.g. A. africanus is more closely related to humans, or their ancestors at the time, than e.g. A. anamensis and many more Australopithecus branches, Australopithecus cannot be consolidated into a coherent grouping without also including the Homo genus and other genera.

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 that the genus was much more widespread than the fossil record suggests), before eventually becoming pseudo-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 gave rise to living descendants, as the genus Homo emerged from an Australopithecus species^{[7][9][10][11][12][excessive citations]} at some time between 3 and 2 million years ago.^[13]

Australopithecus possessed two of the 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.^[14][15] 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).^[16]