Chinese researchers have discovered what is thought to be the world's oldest fossil.
A 55-million year old skeleton of a monkey the size of a mouse was uncovered preserved inside a rock.
According to researchers the discovery, which was published this week in the journal Nature, could help scientists piece together how early primates evolved into humans.
"Now we've got a nearly complete skeleton and it happens to be very close to the ancestors of the human species. From this point we could say that the ancestors of humans have started to evolve,” Professor Xijun Ni, a palaeontologist at the Chinese Academies of Science, said.
It's believed Archicebus achilles, a lemur-like primate, was among the first primates to have emerged after the extinction of dinosaurs.
But Dr Henry Gee, a senior editor at Nature said it was nearly-impossible to determine if a particular fossil was the ancestor of all humans.
“Most we could say is that it looks close to what we would expect the ancestor to look like.”
Scientists say they will continue to study this fossil using computer imaging techniques as it represents “another crucial piece of the puzzle of how we as a species evolved over millions of years.”