The discovery of a new fossil in Egypt that appears to be a younger relative of the “Ida” fossil announced a few months ago (with great fanfare and publicity) has cast considerable doubt on whether Ida is an ancestor of human beings: New Primate Fossil Poses Further Challenge to Ida.

Researchers have named the new primate Afradapis longicristatus, a name that pegs it as an African member of an extinct group of primitive primates known as Adapiformes, to which Ida also belongs. Some researchers have long argued that Adapiformes might be primitive relatives of anthropoids—the higher primates including monkeys, apes, and humans—rather than ancestors of lorises and lemurs. But new fossils found over the past 20 years in Asia and Africa proved to be better candidates for the earliest anthropoids. The discovery of anthropoid-like features in the remarkably complete skeleton of Ida (Darwinius masillae), however, led the researchers who analyzed her remains to resurrect the view that Ida and, hence, adapids, were direct ancestors of anthropoids.

If Ida were truly a missing link between early primates and us, then Afradapis, which appeared 10 million years after Ida, should also share the same traits with the earliest undisputed anthropoids that were alive at about the same time and in the same place. But that’s not what Erik Seiffert of Stony Brook University in New York state and Elwyn Simons of Duke University in Durham, North Carolina, and their colleagues found when they unearthed Afradapis in the Fayum desert of Egypt in 2001. Working with 100 teeth and jaws from multiple individuals—all about 37 million years old—they compared 360 morphological traits in 117 living and extinct primates, in the most complete analysis assembled so far of extinct primates. When they scored Ida and Afradapis against those other primates, Seiffert and colleagues found that adapids do share some traits with anthropoids, such as the loss of a third upper and lower premolar. But these traits evolved more than once among primates, the team reports tomorrow in Nature. They are the result of convergent evolution, which is the acquisition of the same biological trait in unrelated lineages—and, thus, do not indicate inheritance of the trait from a shared ancestor.

I don’t even need to look at the creationist sites to know they’ll all be crowing that this proves scientists are a bunch of big fat stupid idiots — when in reality, what it shows is the real strength of science, in which sometimes a hypothesis is proven wrong and it’s back to the drawing board.

Also see:
The Unveiling of Ardipithecus