Out of Eurasia?

I've just been reading an article in the August issue of Scientific American 'Planet of the Apes'.It's main jist is that most species of fossil great ape between 22mya and 5.5mya lived in Eurasia, not Africa, and it hypthosises that human evolution started in Eurasia and later migrated back to Africa (meeting with the Ardipithecus ramidus about 4.4mya).The section on Great Ape evolution seems quite sound, but the part about human origins seem a bit vague and tacked on at the end. I was wondering whether anyone here knows anymore about this hypthesis? Or could point me in the direction of further reading?

Hmmm...I'll have to dig up that issue, have not taken a good look at it. But Miocene Apes are a real can of worms right now, the nomenclature is really screwed up and so is the evolutionary picture.The basic idea is that the grassland biome expanded during the Miocene and these baboon-like animals expanded into Asia then their descendents reverted to an arboreal strategy. Think of terrestrial quadrupeds like baboons with big canines.It is thought that the Orang-Utan line came from the Sivapithicus/Ramapithicus line.Will have to read the aricle sometime soon. ------------------
Bringer of fire, trickster, teacher.

Finally read it and it does have some interesting points. One is that there is a scarcity of African fossil remains before the A. ramidus find and that the sahelensis find is particularly important since it shows evidence of bipedalism with the reduced canine and the position of the foramen magnum.One of the debates about human evolution is the evolution of bipedalism. The article seems to have brachiation as a primary mode of mobility for sivapithecus and dryopithecus. This would be problematic in a grassland environment since there are few trees to brachiate in, but in a forest environment we could see this happening.A reference to this is found here:Higher Education Support | McGraw Hill Higher EducationI favor the thinking that early apes used terrestrial quadrupedalism then adopted brachiation as they moved into a forest environment with knuckle-walking as a secondary mode with thick tree cover and bipedalism with thinnner tree cover. The need for a grasping foot or a walking foot dictating which mode would be favored evolutionarily. Some favor the idea that brachiation preceded bipedalism.As something of an aside, there is a debate about Gigantopithecus and whether it was bipedal or not. The evidence for this is only in that the mandible has reduced incisors and possibly might have the U shape that bipeds would have. That is, the rows of teeth on either side of the jaw are not parallel. The link has something of an explanation:http://www.ratsnest.net/bigfoot/giganto.htmThe point being that brachiation may not be needed as an intermediate stage between bipedalism and quadrupedalism.Then this link has a copy of the article in SA:Planet of the Apes------------------
Bringer of fire, trickster, teacher.