In what could prove to be a landmark discovery, a leading paleontologist said scientists have dug up the 47 million-year-old fossil of an ancient primate whose features suggest it could be the common ancestor of all later monkeys, apes and humans.

Anthropologists have long believed that humans evolved from ancient ape-like ancestors.

Some 50 million years ago, two ape-like groups walked the Earth. One is known as the tarsidae, a precursor of the tarsier, a tiny, large-eyed creature that lives in Asia.

Another group is known as the adapidae, a precursor of today's lemurs in Madagascar.

Based on previously limited fossil evidence, one big debate had been whether the tarsidae or adapidae group gave rise to monkeys, apes and humans.

The latest discovery bolsters the less common position that our ancient ape-like ancestor was an adapid, the believed precursor of lemurs.

Philip Gingerich, president-elect of the Paleontological Society in the U.S., has co-written a paper that will detail next week the latest fossil discovery in the Public Library of Science, a peer-reviewed, online journal.

"This discovery brings a forgotten group into focus as a possible ancestor of higher primates," Gingerich, a professor of paleontology at the University of Michigan, said in an interview.

The discovery has little bearing on a separate paleontological debate centering on the identity of a common ancestor of chimps and humans, which could have lived about six million years ago and still hasn't been found.

That gap in the evolution story is colloquially referred to as the "missing link" controversy.

In reality, though, all gaps in the fossil record are technically "missing links" until filled in, and many scientists say the term is meaningless.

• Click here to read more on this from the Wall Street Journal.

• Click here to read the full scientific journal report in PLoS ONE.

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