A new discovery of a 14,000 years old thigh bone is all set to amend the history of human evolution. Scientists believe the fossilized femur could add a new branch in family tree of humans.

Previously, historians thought other ancient human species vanished after the appearance of modern humans. But now, the new femur unearthed from Red Deer Cave in southwest China has suggested that human’s distant cousins walked the earth with some other species of humans for quite a long time.

About three years ago, researchers found fossilized skulls in Red Deer Cave situated near Maludong. Earlier this year, researchers also found clues of another possible human species around the cave named after an extinct species of deer.

After analysis, the researchers concluded that the Red Deer Cave people had thick skulls and no chins like Neanderthals, a human species in the genus Homo that vanished between 41,000 and 39,000 years ago. But there were some differences that showed they were not Neanderthals. They combined features and found that they have discovered a new species of humans.

Darren Curnoe, an evolutionary biologist and an author of the new research, said in a statement, “In short, they’re anatomically unique among all members of the human evolutionary tree”.

The new discovery is suggesting the appearance of a new species, but some scientists think the Red Deer Cave people are not a new human species. They believe the fossilized femur is another variation of modern humans.