A primate fossil that was hyped as revealing the earliest evolutionary roots of monkeys, apes and humans is, in fact, as distant a relative as a primate could be, scientists say.
Darwinius masillae, a 47-million-year-old lemur-like creature nicknamed Ida, was dubbed "The Link" in a book and a documentary, but now appears to belong to an extinct fringe branch of the primates that left no living descendants.
Erik Seiffert of Stony Brook University in New York and his colleagues examined 360 anatomical features — the jaw and teeth in particular — of 117 species of primate, living and extinct, and compiled a family tree based on those comparisons.
The researchers also described a newly discovered primate called Afradapis, which lived 37 million years ago in the Eocene period. Its fossil remains were found in Egypt.
The tree places Darwinius and Afradapis in a group called the adapoids, which were not ancestors of the living, higher primates, but shared a common ancestor with smaller primates, the lemurs and lorises.
The scientists' research appears this week in the journal Nature.
Darwinius received almost as much attention for the promotion of the discovery as the discovery itself, as the New York Times dubbed the promotion "science for the Mediacene age."
The fossil was front-page news and even got a custom Google logo "doodle" to commemorate its discovery. It was the topic of a glossy documentary and a book, The Link: Uncovering Our Earliest Ancestor.
The scientists who unveiled Darwinius said it was not a direct ancestor to humans or monkeys, but could show what an ancestor of apes and humans might have looked like. They said it shared some characteristics with higher primates worth examining.
The new analysis says the adapoids don't belong to the same major grouping of primates as apes, monkeys and humans. The features it shares with higher primates, such as the loss of certain teeth, must have evolved independently, the researchers said.
"This is a rigorous analysis based on many features," said Eric Sargis, an anthropology professor at Yale. He said he'd found the argument of the Darwinius researchers unconvincing, so the new result came as no surprise.
The new family tree of primates confirms what most scientists think, said David Begun, a paleoanthropologist at the University of Toronto.
Jorn Hurum of the Natural History Museum in Oslo, Norway, who was an author on the original Ida paper, said he welcomed the new analysis.
"We are happy to start the scientific discussion" about what Ida means for where adapoids fit on the primate family tree, he wrote in an email to The Associated Press.