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 walked upright on two legs, indicating a significant step in human evolution. Fossils of this species have been found in sites like Taung and Sterkfontein. This species is considered a key ancestor of modern humans, as it exhibits both ape-like and human-like traits. Australopithecus africanus had a smaller face and teeth compared to earlier primates, suggesting a diet that included more plant material. Its discovery has provided valuable insights into the evolution of bipedalism and human ancestry.