Final answer:
Raymond Dart discovered Australopithecus africanus in 1924, and Donald Johanson discovered Lucy, a skeleton of Australopithecus afarensis, in 1974. Matthew Berger discovered Australopithecus sediba in 2008, showing a rich tapestry of hominin evolution.
Step-by-step explanation:
The Australopithecus genus, which is integral to our understanding of human evolution, was first discovered by Raymond Dart, an Australian anatomist and anthropologist. The first australopithecine discovered was Australopithecus africanus, in 1924. A significant fossil find from this species was the Taung Child, a skull of a juvenile individual which Dart meticulously worked on, indicating a combination of ape-like and human-like features and bipedalism.
Another key discovery was made by American paleoanthropologist Donald Johanson in 1974, who found a 40 percent complete skeleton of an adult female australopithecine in the Afar region of Ethiopia. The skeleton, known as Lucy, belonged to Australopithecus afarensis, a species with significant implications for the study of human ancestors.
Additionally, Australopithecus sediba was discovered in 2008 by Matthew Berger, the young son of American paleontologist Lee Berger. This species displayed a mix of traits that suggested both tree climbing abilities and bipedal locomotion, highlighting the complex and adaptive nature of early hominins.