Last year, Science magazine's Breakthrough of the Year was the description of a new species of fossil primate, believed to be on the human line of descent but a million years older than the famous "Lucy." The type specimen of the new find was nicknamed "Ardi."
Now other scientists are challenging the placement of Ardi on the human line, saying it branched off somewhere closer to the common ancestor of humans and apes. Analysis of teeth, skull shape, wrist bones, etc. gets very technical, but the bottom line is some researches want Ardi booted out of the family. The original describers, not surprisingly, are standing their ground.
COMMENT: The important lesson, stressed by everyone involved, is that this kind of debate is normal and healthy in science. In this case (as in the Flores "hobbit" dustup) it may take more specimens, preferably from other locations, to get a definitive answer.