PS. Also the fact that Neanderthal & Cro-Magnon were contemporaries added to the reasons why they were thought sub-species, and to be sure, still are in a sense. Or, to be more precise, their status is currently indecisive between a sub-species or a fully distinct species. However, one thing that is now much, much clearer that it was just a decade ago is that Neanderthal and Cro-Magnon behavior was far more different than had been thought the case. The Neanderthal had inferior tools, inferior weapons, inferior artistry, etc.
I suppose, then, that the natives at the source of the Nile were a subspecies (or a separate one altogether) of those that lived at the mouth of the Nile 3000 years ago?
Do you believe it possible that tools/artifacts/art/food/customs/etc. are subjected to modern ethnocentric prejudices?
What does the level of technological development or cultural sophistication have to do with determining species? We have people on this planet living in the stone age while others can split an atom. Yet, they can interbreed producing viable offspring which means they are from the same species.
"The Neanderthal had inferior tools, inferior weapons, inferior artistry, etc."
That could be said for many people today I suppose. Does that make them sub-species? If so, a sub-species of what?