this really isn't that new. it's been clear for a while now that there are far too many named species; there was paleoanthropological literature produced in the 80s and 90s that put forth the idea that all these homo *s are just presenting variation, and they need to be condensed into two or three species rather than a dozen or more. you're fighting against the egos of the researchers. this will eventually come out in the wash.

if neanderthals and sapiens produced viable offspring, and it is clear now that they did, then what that means is that - by definition - they were actually not distinct species. rather, what you're seeing in the difference in the bones is just local variation.

likewise, there wasn't a dozen "archaic" species in africa, but merely a lot of variation. these are going to need to be deleted.

now, the next question is regarding erectus. i don't see any reason to rule out interbreeding, a priori, by analyzing bone fragments. rather, it strikes me as entirely reasonable to project a discovery of erectus genes, should they be possible to really analyze.

once you get to more primitive forms, you lose the ability to differentiate. that is, you can place early sapiens (which probably interbred with ergaster) in africa, neanderthalensis in europe, the denisovans in northern asia and erectus in southern asia. but these would all just be local populations, not distinct species. any further hybridizing would exist within these base populations, which would have existed in these regions for a very long time before the out of africa migration.

the result is nothing revolutionary. it's merely a synthesis of the once competing singular and multi-regional hypotheses - out of africa, yes, but what came out of africa interbred with local populations wherever it went, creating continuity in local populations.

http://www.youtube.com/watch?v=0ScqOVxPHA8