It's long been believed that members of the genus Australopithecus evolved into the genus Homo. Everyone in anthropology, it seems, has a different opinion on how and when. A unique australopithecine with some human traits but extra-long arms, a South African species named Australopithecus sediba, may have split off about two million years ago and set out on a path that led to us.
Or not. The creature's uniqueness as a species seems well agreed on, but was it on the "critical" path to humans, or just an interesting side branch? The search to find - and properly classify - the countless links in the evolutionary chain goes on.