南方古猿属属

该属最初被发现的化石是“露西”。根据化石证据，南方古猿的成员兼具人类和猿类的特征。它们与现代人类相似，都是双足行走（即用两条腿行走），但像猿猴一样，它们的大脑很小。它们的犬齿比猿类的小，而颊齿比现代人类的大。

Australopithecus (, OS-trə-lə-PITH-i-kəs, -⁠loh-; or, os-TRA-lə-pi-THEE-kəs, from Latin australis 'southern' and Ancient Greek πίθηκος (píthēkos) 'ape') is an extinct 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, which sometimes also includes Ardipithecus, 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.

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 genus Homo 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 extinct 1.9 million years ago (or 1.2 to 0.6 million years ago if Paranthropus is included). While no members of the genus Australopithecus survive today, there are living descendants, such as the genus Homo, which evolved from Australopithecus at some time between 3 and 2 million years ago.

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. 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).