Source: BBC

By Pallab Ghosh Science correspondent, BBC News

Fossils from Northern Kenya show that a new species of human lived two million years ago, researchers say.

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 monkey to ape to modern human.

The research has been published in the journal Nature.

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 ago 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.

With the discovery of the three new fossils researchers can say with more certainty that H.rudolfensis really was a separate type of human that existed around two million years ago alongside other species of humans.

For a long time the oldest known human ancestor was thought to be a primitive species, dating back 1.8 million years ago called Homo erectus. They had small heads, prominent brows and stood upright.

But 50 years ago, researchers discovered an even older and more primitive species of human called Homo habilis that may have coexisted with H. erectus. Now it seems H. rudolfensis was around too and raises the distinct possibility that many other species of human also existed at the time.  Read further.