Australopithecus << `aw` struh loh PIHTH uh kuhs >> , is a group of early humanlike creatures. These creatures lived in Africa from about 4 million years ago to about 1 million years ago. Members of the genus (group of species) Australopithecus are called australopithecines. The remains of australopithecines are among the oldest known hominin fossils. In scientific classification, hominins make up the group that includes human beings and prehistoric humanlike species.
Australopithecines stood upright and walked on two legs. They grew about 3 1/2 to 5 feet (110 to 150 centimeters) tall and had large projecting faces with large molars (back chewing teeth). The size of their brains was about one-third the size of a modern human brain. The male australopithecines were larger than the females.
Most anthropologists recognize at least eight species of Australopithecus. They are A. anamensis, A. afarensis, A. africanus, A. aethiopicus, A. garhi, A. sediba, A. boisei, and A. robustus. Although all the australopithecines had large faces and molars, A. aethiopicus, A. robustus, and A. boisei had much larger jaws and teeth than the other species. These three species are often called the robust australopithecines. The other species are called gracile (slender) australopithecines. Some anthropologists put the robust species in a separate genus, called Paranthropus.
Scientists think that humans developed from a species of australopithecine. However, they are not sure which species is ancestral to the first humans. The oldest fossils that are recognized as members of the genus Homo, which includes modern humans, are known from fossil sites in Africa and dated from about 2 million to 2.4 million years old.
Australopithecine fossils were first recognized in 1924 when the South African anthropologist Raymond Dart identified a child’s skull that had been found at Taung, near Vryburg, South Africa. Dart named the creature Australopithecus africanus. He believed it was a human ancestor, but most scientists thought it was an extinct ape. Additional fossils found over the next 35 years convinced scientists that Australopithecus was a hominin.
In 1974, researchers discovered a partial skeleton of a female australopithecine at Hadar, Ethiopia. The fossil is about 3.2 million years old. Nicknamed “Lucy,” she walked upright but had arms that, in proportion to her body, were longer than those of modern people. In 1978, researchers at Laetoli, Tanzania, found fossil footprints together with fossilized bones of a hominin that lived 3.6 million years ago. Anthropologists have classified “Lucy” and the Laetoli fossils as Australopithecus afarensis. These discoveries demonstrated that the Australopithecines walked fully upright, reinforcing the idea that this group is ancestral to human beings.
In 2010, anthropologists announced the discovery of a new gracile species called Australopithecus sediba at a site called Malapa in South Africa. It is about 2 million years old. Features of the skeleton show that A. sediba had an odd mix of primitive and modern characteristics. In 2015, anthropologists announced that fossils of a new gracile species were discovered near Hadar. This new species, called Australopithecus deyiremeda, lived alongside “Lucy” and her kind about 3.4 million years ago. However, most scientists believe that more fossils must be found to determine if A. deyiremeda is a distinct species from A. afarensis.
