Many people will admit to having the odd rogue ancestor.

But now scientists believe we may all be related to cannibals.

The claim comes after the discovery of what is thought to be the oldest human species: a toothy tree swinger named Homo gautengensis.

The new species emerged more than two million years ago and died out approximately 600,000 years ago, according to Dr Darren Curnoe, the anthropologist who identified him.

It is based on two million- to 800,000-year-old fossil-skull pieces, jaws, teeth, and other bones found at the Sterkfontein caves complex in South Africa's Gauteng Province.

Dr Curnoe, of the University of New South Wales in Australia, believes the earliest known man may have been cannibal due to wounds discovered.

The marks on the Stw 53 skull show 'that it was de-fleshed, either for ritual burial or cannibalistic consumption,' he said.

Along with burned bones, the marks suggest that man 'was certainly on the menu of Homo gautengensis,' Dr Curnoe added.

But Homo gautengensis, who thought to measure 3ft 6in high and weighed just over seven stone, wasn't exclusively carnivorous.

The new species had teeth apparently adapted for eating plant material that looks to have required plenty of chewing, according to the study, soon to be published in the human-biology journal Homo.

Compared with modern humans, the new species had proportionally long arms, a projecting face somewhat like a chimp's, larger teeth, and a smaller brain—though not too small for verbal communication.

'While it seems possible that Homo gautengensis had language,' Curnoe said told National Geographic magazine, 'It would have been much more rudimentary than ours, lacking the complex tones and lacking a grammar, as all human languages have.'

Due to these missing abilities, its anatomy and geological age, the researchers think that it was a close relative of us, but not necessarily our direct ancestor.

The discovery of this new human not only adds to our overall family tree, but it may also lead to a big shake-up.

For decades, scientists have been searching for the species that eventually evolved into the first Homo genus member.

Earlier this year, it was announced that this 'missing link' human may have been unearthed — in the form of Australopithecus sediba.

The newly identified human, however, throws a wrench into that theory, because the former was 'much more primitive than Homo gautengensis, and lived at the same time and in the same place,' according to Dr Curnoe.

As a result, 'Homo gautengensis makes Australopithecus sediba look even less likely to be the ancestor of humans.'

Dr Curnoe instead proposes that Australopithecus garhi, found in Ethiopia and dating to about 2.5 million years ago, is a better possibility for the earliest non-Homo direct ancestor in the human evolutionary line.

He still regards East Africa as being the cradle of humans, 'because it has the oldest fossil record, going back to about seven million years, but we are clearly learning now that there was much greater diversity in our evolutionary tree than we realised for a long time.'