The mystery of the location of this new species in the human family tree is because the fossils have not yet been dated. The reason for that is not explained in the Scientific American article, but it does discuss the ramifications of what it will mean when the dates are determined:
The bones could be several million years old or tens of thousands of years old, though the team seems to favor the idea that H. naledi stems from a point close to the origin of Homo. (The oldest known fossil of Homo is a lower jaw bone from Ethiopia that dates to 2.8 million years ago).
However old the Homo naledi bones turn out to be, they will dramatically impact how scientists interpret human evolution, Berger says. If the remains are quite old, then certain physical and behavioral traits associated with later Homo emerged surprisingly early, and possibly in species that did not give rise to H. sapiens. If the remains are intermediate in age, some of their more australopithecine-like traits might be the result of reversals, in which a more primitive trait re-evolves, possibly because it becomes adaptive again in some way. If the remains are young, then scientists will have to come to terms with the fact that a small-brained human species with tool-wielding hands managed to persist alongside larger-brained human species—possibly including H. sapiens—for an amazingly long time. In that case, says team member John Hawks of the University of Wisconsin, perhaps H. naledi was among the archaic human species that interbred with H. sapiens and thereby contributed DNA to the modern human gene pool, like Neandertals did. (The team plans to try to obtain DNA from the H. naledi bones, though the warm, damp conditions in the cave system are not ideal for preservation of ancient DNA.)
Beyond that mystery, there’s yet another one which we’ll explore on the next page…
[nextpagelink][/nextpagelink]