The discoveries suggests that at least three distinct species of humans co-existed in Africa.
The research adds to a growing body of evidence that runs counter to the popular perception that there was a linear evolution from early primates to modern humans.
Anthropologists have discovered three human fossils that are between 1.78 and 1.95 million years old. The specimens are of a face and two jawbones with teeth. The finds back the view that a skull found in 1972 is of a separate species of human, known as Homo rudolfensis. The skull was markedly different to any others from that time. It had a relatively large brain and long flat face.
But for 40 years the skull was the only example of the creature and so it was impossible to say for sure whether the individual was an unusual specimen or a member of a new species.