Comments on: What did the immediate ancestor of chimps and humans look like?

By: Luna_the_cat

Luna_the_cat — Wed, 20 Feb 2008 11:32:30 +0000

So the current idea, then, is that Proconsul is not on the ancestral line to African apes at all?Not trying to be awkward, just sorting out the lines of descent in my head.

By: Greg Laden

Greg Laden — Wed, 20 Feb 2008 10:25:27 +0000

Luna,It depends on how far back your conception of Proconsul dates to. Proconsul is a genus that includes specimens that have been reworked (taxonomically) a few times. The miocene apes probably split into two broad categories, one that would eventually include the living African apes (including humans) and the other, which includes Proconsul.

By: Luna_the_cat

Luna_the_cat — Wed, 20 Feb 2008 05:33:02 +0000

Where does Proconsul fit into this picture, just out of curiosity?

By: Anne Gilbert

Anne Gilbert — Tue, 19 Feb 2008 18:55:02 +0000

Greg:I’m going to link your piece to my own Palanthsci e-mail list. This is really very good, and I’m glad you’ve written about it.Anne G

By: Greg Laden

Greg Laden — Tue, 19 Feb 2008 08:49:20 +0000

There are no unambiguous fossils of the chimp-human LCA. That would be too easy.

By: Laelaps

Laelaps — Tue, 19 Feb 2008 08:38:39 +0000

I remember asking a close friend of mine about the fossil record for the chimpanzee side of the split recently; she held up her hand in the shape of a 0. Perhaps there are a few scraps, but I really hope there’s a more concerted effort to fill in the gaps on the chimpanzee side, especially since it would either support or refute some of what you’ve mentioned above.I agree that chimps, for the most part, are the best model we have for the LCA. That being said, even though I didn’t agree with Aaron Filler’s mechanism I am intrigued with his hypothesis that knuckle-walking is a derived trait and that the LCA might have been more gibbon-like in form (which goes back to Sir Arthur Keith).Unfortunately fossils of the lineage leading up to chimpanzees are going to be hard to find; if they remained in the forest taphonomy is against us, but I think it’s still important to look. Coming up with some such remains would be a test of the modern chimpanzee as a model for the LCA and either support what was said here or cause us to revise our ideas. Perhaps the research isn’t as “sexy” as searching for the earliest humans, but I think it’s just as important to understanding our own evolution.

By: stavros

stavros — Tue, 19 Feb 2008 08:23:05 +0000

Greg, all these hypotheses and arguments: are they based on the fossil records? You also mention genetic evidence, this is DNA analysis or is it something else?Thanks!