The human-chimpanzee last-common ancestor has been variously dated at anywhere from 13 million to 4 million years ago. So this latest tooth does seem to fall within that range. It's interesting that it was found outside Africa. I'm inclined to agree with Sculptor that our current picture of human evolution is probably woefully simplistic. Things were probably far more complicated than we currently hypothesize. (Biology is always like that.) In particular, I don't see all of human evolution taking place in one favored place (Africa) and an out-of-Africa event as a mass exodus that suddenly populated the rest of Eurasia with more or less finished humans. I'm more inclined to imagine lots of tiny hunter-gatherer bands of individuals of many different sorts (some more human, some less) kind of continually leaking out of Africa over long periods of time. Some probably went east into Yemen and South Asia. Others probably went northeast into Israel and the Levant, then into Europe and Central Asia perhaps. (Neanderthals and Denisovans may be descended from these.) Others may have crossed the Straits of Gibraltar. Tracing the detailed histories of these small widely-dispersed populations and the extent to which their decendants interbred with later more anatomically modern arrivals might be very hard to reconstruct.