Australopithecus africanus is an extinct species of hominin that lived in southern Africa around 2 to 3 million years ago. It is known for its small brain size, similar to that of modern apes, but it also exhibited bipedalism, walking upright on two legs. Fossils of this species have been found in sites like Taung and Sterkfontein, providing important insights into human evolution. This species had a combination of ape-like and human-like features, including a small, prognathous face and long arms. Australopithecus africanus is considered a key ancestor in the evolutionary lineage leading to modern humans, highlighting the transition from tree-dwelling to ground-dwelling lifestyles.