Final answer:
Gracile australopithecines from South Africa include Australopithecus africanus and Australopithecus sediba, characterized by a slender build and smaller teeth and jaws.
Step-by-step explanation:
Two gracile australopithecines from South Africa are referred to as Australopithecus africanus and Australopithecus sediba. These species are part of a genus of hominins that evolved approximately four million years ago and include other species such as Australopithecus anamensis, A. afarensis, A. garhi, and A. bahrelghazali. The gracile australopithecines had a slender build, were bipedal, and had certain features such as a more pronounced projection of the face (prognathism) and smaller teeth and jaws compared to their robust counterparts, which include species like Paranthropus robustus, P. boisei, and P. aethiopicus. The robust australopithecines had a sagittal crest to support large temporalis muscles necessary for their diet of tough plant materials. Although gracile australopithecines vanished from the fossil record around two million years ago, they are significant in understanding human evolution as they share more common features with the genus Homo, to which modern humans belong.