This Darwinius masillae fossil, aka Ida, is a 47-million-year-old primate skeleton.

AP Photo/Mary Altaffer

On May 19, 2009, researchers held a press conference at the American Museum of Natural History. From behind a podium bearing the slogan "The Link: This Changes Everything," speakers talked about a fossil known as Ida. The fossil, they explained, was an amazing find that would change our understanding of evolution. In video clips released as part of the media package, Richard Attenborough said, "Now people can say, 'You say we're primates, like monkeys and apes, and that we came from very simple, generalized mammals. Show us the link.' The link ... until now, is missing. Well, it is no longer missing."

Within hours, the mainstream media and the blogosphere were abuzz with the news about Ida (pronounced EE-dah). "Scientists find the missing link," declared a headline at the Daily Mail online. But almost immediately, the dust started to settle. Journalists and scientists had a chance to read the academic paper describing the find, published in the journal PLoS ONE on the day of the announcement. Headlines did a 180 over the next couple of days: One, in Time, read, "Ida: Humankind's Earliest Ancestor! (Not Really)."

The original paper, "Complete Primate Skeleton from the Middle Eocene of Messel in Germany," contains no reference to a creature called Ida. Instead, it describes a 47-million-year-old fossil of an animal dubbed Darwinius masillae. Collectors excavated the fossil in 1983, split it into two pieces -- the fossil known as Ida and its mirror image -- and sold them separately. At the time, the two halves were identified as a different animal and weren't hailed as particularly important.

But almost 20 years later, Dr. Jorn Hurum rediscovered the more complete half of the fossil through an unnamed collector. He shelled out $750,000 to purchase it for the Natural History Museum of the University of Oslo [source: Devlin]. Hurum assembled a team of researchers to analyze the find. The media bonanza that declared it the missing link came after two years of work on the specimen.

But the idea that Ida is the missing link has more to do with the news coverage surrounding the fossil than the research itself. Without ever using the term, the paper does describe the fossil as a missing link -- a fossil that has traits from two different types of animals and may form an evolutionary link between them, of which there are many. It doesn't, however, present the fossil as "the missing link" -- a direct bridge between humans and early primate ancestors.

So if Ida isn't the missing link, what is it?