The term australopithecine refers to two very closely related genera within the Hominina subtribe of the Hominini tribe. They appeared in the Pliocene: Australopithecus, appeared about 4 million years ago; Paranthropus, appeared about 2.7 million years ago. When used alone, the term refers to both genera together. Australopithecus is sometimes referred to as the "gracile (slender) australopithecines", while Paranthropus are also called the "robust australopithecines". A likely ancestor of the Au… (More on Australopithecine)