Austropithecus, often referred to in its more commonly known form as Australopithecus, is a genus of hominins that lived in Africa between about 4 and 2 million years ago. They are considered some of the earliest ancestors of modern humans, showcasing both ape-like and human-like characteristics. Australopithecus species, such as A. afarensis, are known for their bipedal locomotion and relatively small brain sizes compared to modern humans. Their fossils provide crucial insights into human evolution and the transition from tree-dwelling to upright walking.