It doesn't make sense that no one in Europe would develop light skin without the Proto-Indo-Europeans. At least if we're assuming that "dark skin" means as dark sub-Saharan Africans, I think skin colour and physical features (with an obvious bias toward what we consider "white") like the Inuit and other circumpolar people (including the Sami apparently before Nordic admixture) is plausible. Even the article you posted doesn't suggest it was the proto-Indo-Europeans who spread light skin in Europe.
At the time of the pod white skin already exists, and i wasn't arguing against that. what i was talking about how. and how fast it would spread compared with otl, considering that with anothe rlanguage, the culture will also be different.
no, skin would be dark brown, not black. the other physical features like the shape of the face would be current european, just not the skin tone.
http://www.livescience.com/42838-european-hunter-gatherer-genome-sequenced.html
this is how it would look like: