An ankle bone discovered in central Burma could be evidence of an ancient ancestor common to many of today's primates, including humans.
The bone is just over a centimetre long
The 45-million-year-old fossil has features that link it to all of the anthropoids, the grouping of human-like species such as apes and monkeys.
If correct, this would tie their line of evolutionary descent to Asia and not Africa as some have suggested.
The findings appear in the Proceedings of the National Academy of Sciences.
The PNAS journal presents a paper on the discovery by Laurent Marivaux, of the University of Montpellier II, and colleagues.
They say the way the left tarsal bone might have moved in the joint would have been typical of known, early anthropoids, which clambered about in trees.
They even speculate that the remains may have belonged to an anthropoid species known as Amphipithecus, a large, ape-like animal.
The implication of the team's research is that humans' primate ancestor may have had Asian origins.
The PNAS report suggests the Burma descendents would have moved into what is Africa before evolving into the various human species that then spread back out across the globe in the last few hundred thousand years.