I posted a link to this article a few years back under a post titled 'Scientists Wanted'; the new 'space' theorists might want to ask the question; who/what's creating the empty space for creatures to move into and subsequently evolve? Vrba's turnover pulse hypothesis incorporates all other theories including this new space theory. The naysayers keep going back to their same stomping ground, North East Africa or Turkana Boy to disprove Vrba's theory, seemingly, totally ignoring Southern Africa, "the cradle of humankind" famous for Raymond Dart's Taung Child fossil.

http://en.wikipedia.org/wiki/Australopithecus_africanus