Name:

Australopithecus (Greek for "southern ape"); pronounced AW-strah-low-pith-ECK-us

Habitat:

Plains of Africa

Historical Epoch:

Late Pliocene-Early Pleistocene (4-2 million years ago)

Size and Weight:

About 4 feet tall and 50-75 pounds

Diet:

Mostly herbivorous

Distinguishing Characteristics:

Bipedal posture; relatively large brain

 

About Australopithecus:

Although there's always the possibility that a stunning new fossil discovery will upset the hominid apple cart, for now, paleontologists agree that the prehistoric primate Australopithecus was immediately ancestral to genus Homo--which is now represented by only a single species, Homo sapiens.

The two most important species of Australopithecus were A. afarensis, named after the Afar region of Ethiopia, and A. africanus, which was discovered in South Africa. Dating to about 3.5 million years ago, A. afarensis was about the size of a grade-schooler; its "human-like" traits included a bipedal posture and a brain slightly bigger than a chimpanzee's, but it still had a distinctly chimp-like face. (The most famous specimen of A. afarensis is the famous "Lucy.") A. africanus appeared on the scene a few hundred thousand years later; it was similar in most ways to its immediate ancestor, although slightly bigger and better adapted to a plains lifestyle. A third species of Australopithecus, A. robustus, was so much bigger than these other two species (with a bigger brain as well) that it's now usually assigned to its own genus, Paranthropus.

However, it's important not to overstate the extent to which Australopithecus was similar to modern humans. The fact is, the brains of A. afarensis and A. africanus were only about a third the size of those of Homo sapiens, and there's no convincing evidence that these hominids were capable of using tools (though some paleontologists have made this claim for A. africanus).

In fact, Australopithecus seems to have occupied a place fairly far down on the Pliocene food chain, with numerous specimens succumbing to attacks by the carnivorous megafauna mammals of their African habitat.