Robust (left) and gracile (right) australopithecines

Gracile and Robust Morphologies

The australopithecines are usually separated into two morphological types on the basis of their body build:gracile forms (Australopithecus afarensis and A. africanus) and robust forms (A. robustus, A. boisei and A. aethiopicus).

Though probably little different in overall body weight, these two forms must have looked very different in stature and facial appearance.

These reconstructions represent what we know of the robust and the gracile australopithecines respectively.

The skulls are built on the same plan but the robust form has relatively bigger teeth, along with larger jaws and jaw muscles.

Both forms were capable of walking on two legs but the arrangement of the legs and feet was different from modern man.

Remains of arm bones indicate that the upper limbs of the australopithcines were longer than equivalent modern human bones.