Australopiths lived in Africa from about 3 to 1.4Myr ago. The australopiths show advances over Praeanthropus afarensis (Lucy) in the flattening of the face , the loss of the diastema between incisors and canines and the small canine teeth. They show some specialisations that place them off the line to modern humans eg molars and premolars are more massive and covered in layers of thick enamel - adaptations to a tough plant diet.

Two size classes lived at the same time Australopithecus africanus was 1.3m tall and gracile while Paranthropus robustus, P. boisei and P. aethiopicus were taller, heavier with slightly larger brains (520cm3 against 445)

source p381