They had biped behavior and the appearence of apes.
I have to thank to Moacir Elias Santos, a Brazilian archaeologist that took a serie of pictures of a cast skull on Museu Egipcio e Rosacruz.
The skull used was reconstructed with PPT GUI (scanning by picture).
The skull of chimp was deformed using Lattice modifier on Blender 3D, until match with the Australopithecus skull. Obviously, the skin was deformed too.
I hope you enjoyed.
A big hug!