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Re: Tiktaalik



David Marjanovic wrote:

I don't think so. The toothplates and jaws of lungfish are quite awe-inspiring. (For example lungfish don't have an upper jaw -- just a palate.) The cocoon is almost unique among vertebrates as well.

I'm talking body plans. So was Daeschler et al. (2006) in their _Nature_ paper. The term "body plan" is even in the title. No matter how awe-inspiring a lungfish's cakehole is, it's not going to help it move around on land. Of course, no offense to lungfishes is intended...


Sorry, I can't help it -- this all sounds so much like an argument for ranks :^)

Oh no! Not those horrible "ranks"! I'm not talking typology here (heaven forfend!), but transformations involving locomotion in (or on) two different kinds of media. Tetrapods (including ourselves) are still just uppity lobe-finned fish, and birds will always be theropods. But both transitions involved major transformations, associated with water-to-land and land-to-air. (The latter is still true even if birds evolved from arboreal theropods, because no known non-avian theropod is specialized for arboreality; they retain the terrestrial-bipedal body plan primitive for Theropoda.)


Not convinced? Ask yourself this: Why did _Nature_ magazine dedicate a combined 18 pages to the discovery of _Tiktaalik_? It made the cover too. It was not just because this critter was "photogenic" (though it was that too).

Cheers

Tim