Australopithecus is the point just above gorillas, which then splits in two directions: chimps and humans.  

The Leakeys believed in one continuous line, hence they searched for the "missing link" between humans.

Read the Haraway essay on the way Leakey created the field of primate studies, choosing Jane Goodale to study chimps because he felt that women would better understand what he saw as evolutionary primitive versions of humans.  Men find the bones.  Women get to play with monkeys.  Leakey was a sociopath.

Ah, this is great stuff.  But off topic...