Final answer:
The fossil remains of Australopithecus afarensis were discovered in the Afar region of Ethiopia and further specimens have been found in Kenya and Tanzania. The first discovery of Australopithecus africanus was made in South Africa, with the Taung child being the most notable find. Both species are key to understanding the evolution of bipedality in hominids.
Step-by-step explanation:
The species Australopithecus afarensis was first identified from fossils found in the Afar region of Ethiopia by the American paleoanthropologist Donald Johanson in 1973. The most famous of these fossils is the partial skeleton known as Lucy, with the identification number KNM-AL-288, and is dated to around 3.75-2.8 million years ago (MYA). Subsequent discoveries of this species have occurred in Kenya and Tanzania, enhancing our understanding of their geographical spread within East Africa.
As for Australopithecus africanus, it was the first of the australopithecine to be discovered, with the most well-known specimen being the Taung child, found in South Africa and described by anatomist Raymond Dart. A. africanus lived between two and three million years ago, and is known for its slightly larger brain and slender body compared to A. afarensis. This species is particularly important as it demonstrates some key traits of early bipedal hominids, despite smaller brain sizes comparable to that of a chimpanzee.
Both A. afarensis and A. africanus provide crucial insights into the early stages of human evolution, helping us understand the adaptations and environments that shaped the development of upright walking and other human-like characteristics.