The Australopithecines are thought to represent a single evolving lineage. This lineage has many 'primitive' or ancestral features. These features suggest that the Australopithecines are not far removed from the common ancestor of humans and chimpanzees. Scientists believe that there were seven species of the genus Australopithecus. All species but Australopithecus afarensis are believed to have been evolutionary dead ends. This is under debate, however, since the species Australopithecus africanus is believed to possess many more human-like characters.
Some features of the genus Australopithecus are as follows: strong prognathism( where the lower face extends far beyond the eyes), a flat cranial base, large canines, long arms relative to the rest of the body, a relatively small brain(400 cc) and curved bones in the fingers and toes. These bones suggest that Australopithecus afarensis climbed trees. Australopithecus africanus is much more ape-like in its limb proportions. This suggests that it spent more time in trees than did A. afarensis. But the pelvic structure and also the structure of the hind limb indicate that both A. africanus and A. afarensis were bipedal. It is believed that the south, from which Australopithecus africanus comes, stayed more forest-like for a longer period of time than did the east. A. afarensis comes from the east. Australopithecus afarensis would have roamed the savannas and woodlands. Australopithecine footprints of three individuals have been found in a rock formed of volcanic ash in Tanzania . Unlike later hominid forms, Australopithecus afarensis is not thought to have made or used stone or bone tools.
Here is an artist's interpretation of what australopithecus africanus would have looked like.