Australopithecus

Australopithecus was a prehistoric hominid that lived 4 to 3.5 million years ago. There are many species. Humans are thought to have evolved from the Australopithecus species A. afarensis.

Description
Australopithecus tended to be diminutive and gracile, most specimens measuring 1.2 to 1.4 metres high. They shared several traits with modern apes and humans, but their brains were roughly 35% the size of a modern human's brain. Australopithecus also showed sexual dimorphism, with males being up to 50% larger than females, where as in humans, males are, on average, 15% larger than females.

Popular Culture
A group of Australopithecus appear in Episode 23 of Primeval, where Helen Cutter tries to poison them at Site 333.