Possible New Hominid Species Discovered in Siberia

Reuters is running with a story about genetic research being done on hominid material discovered in Siberia that, according to researchers, suggests the presence of a new species of hominid that lived until around 30 thousand years ago. The author writes:

"It really just looked like something we had never seen before," Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told a telephone briefing.

"It was a sequence that looked something like humans but really quite different."

Writing in Nature, Krause and colleagues said they sequenced DNA from the mitochondria, a part of the cell, which is passed down virtually intact from a woman to her children. They compared it to DNA from humans, Neanderthals and apes.

The sequence indicates the hominin's line diverged about a million years ago from the line that gave rise to both humans and Neanderthals and that split about 500,000 years ago.

I always have grave misgivings when geneticists, in the complete absence of diagnostic palaeontological material, proclaim that a new species has been discovered. For one thing, we don't have the genetic sequences for the intermediates between the find in Siberia and contemporary humans. How many substitutions denote a different species? This is where systematics can get away from us. If we don't have the intermediates, how do we know where the proper branch is? To be fair, the researchers, themselves, are reticent to go the 'new species' route yet but it seems they are leaning that way.