Final answer:
Australopithecus africanus was a bipedal early hominid with a slender build and larger brain size relative to A. afarensis. Distinguishing features include less pronounced sexual dimorphism, human-like pelvic shape, and traits suggesting bipedal posture and locomotion. The Taung child is a key specimen demonstrating its mix of ape-like and human-like characteristics.
Step-by-step explanation:
Australopithecus africanus is one of the early hominids that lived between two and three million years ago, with several characteristics that differentiate it from other members of the Australopithecus genus. A. africanus had a more slender build compared to others and was bipedal but also had robust arm bones, indicating it may have spent significant time in trees. Its brain size was approximately 500 cubic centimeters, larger than that of A. afarensis, but still less than one-third the size of the modern human brain. Compared to the great apes, A. africanus showed less sexual dimorphism with males being less proportionally larger than females than in modern gorillas and orangutans. Notably, it shared with modern humans the characteristic of bipedalism; for example, the positioning of the foramen magnum and pelvic shape suggested this bipedality.
Australopithecus africanus was first identified from the Taung child skull discovered by Raymond Dart. The skull displayed a blend of human-like and ape-like features, with notable aspects being minimal prognathism, small canines, no diastema, and an anterior position of the foramen magnum, all indicating bipedal locomotion and upright posture. The species fell into the category of gracile australopiths, meaning that they had a relatively less robust facial and dental morphology compared to the robust australopiths.