I've said this before, but why do people continue to consider Neanderthals a different species when there appears to be a lot of evidence that they 'interbred' (horrible word) with other humans and produced fertile offspring?
The definition of species is:
A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction.
Ergo, Neanderthals (and probably other, somewhat different humans) must have been part of the same species.
Anyway, we clearly still know so very, very little about pre-history.