5-7 million years ago: divergence between hominids and chimpanzees.
DNA molecular analysis has revealed that humans and chimpanzees, bonobos included, share a common ancestor that lived between 5 and 7 million years ago.
Unfortunately, both chimpanzees and bonobos live in warm, tropical rainforests, where organic material decomposes rapidly and does not preserve. Therefore, there are no remains of fossilized ancestors of these species dating 5 million years ago or less.
The human case is different. There are several known species of potential ancestors, such as Australopithecus afarensis, Homo habilis and Homo erectus.
Bonobos and chimps evolved in isolation – they suffered allopatric speciation ─ because, at some point, the Congo River separated both species. Bonobos live in the south of the river and chimps live in the north. Since these species never swim, their genes have not mixed for the last 2 to 3 million years.