One way that the genus Australopithecus differed from apes is that they had a less slanted forehead. This was primarily seen in the africanus species of Australopithecus. Australopithecus evolved more than 4 million years ago and shares a common ancestor with humans and chimpanzees.
There are two main types of Australopithecus: gracile and robust. The robust Australopithecus were more heavily built than the gracile Australopithecus. Their diet mainly consisted of tough vegetables, while the gracile had a more variable diet. The genus lived primarily in East and South Africa. Several different species evolved, including A. anamensis, A. africanus, A. sediba and A. garhi. The Homo genus derived from the Australopithecus approximately 3 million years ago. The Australopithecus genus became extinct approximately 2 million years ago.
Australopithecus differentiate from earlier primates by their bipedal stature, or ability to walk on two legs. The males of the genus were typically larger than the females. They evolved the ability to make tools and use their hands in complex ways. A. africanus had smaller canine teeth than great apes. While they had a small cranial capacity, it was about two times larger than those of apes of comparable size and about 35 percent the size of the modern human brain.