This is news?
Wow, I've been saying this for years now. Add together the age of fossils, geographic distances, and a small global Human population and this is a no brainer. Many people don't seem to realize that highways, ocean liners, and airlines didn't exist back then. Small groups of intrepid explorers would set out into the vast worldwide wilderness and never be seen again. They would be totally isolated to develop and evolve, cut off from other populations.