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Re: linguistic analogy
On Mon, 12 Feb 1996, Rob Meyerson wrote:
> Nick Pharris writes;
> >Many features make birds "different enough" for their own category,
> >Aves. But that category, Aves, is still part of Dinosauria (and
> >Theropoda, Maniraptora, etc.).
> If we place the Dinosauria taxa at a superclass level, then I'll
> agree with you.
It would have to be a lot higher than a superclass, if you want to keep
Aves as a class; because Aves must also be subsumed under Theropoda,
Tetanurae, Coelurosauria, Maniraptora...
> >I have two responses to this:
> >1) Whales have evolved a whole host of new features. Echolocation, for
> >one (secondarily lost in baleen whales), and flukes, and dorsal fins, and
> >many modifications to the lungs.
> I'll concede your echolocation and fluke points. However, the rest
> are simply the result of modifying existing structures.
I think the development of flukes, dorsal fins, melons, click-producing
apparati, retia mirabilia, etc., practically from scratch, are far
greater modifications than the ossification and amplification of a
pre-existing cartilagenous sternum!
> >2) All of the "new features" of birds are just modifications of those
> >found in other maniraptorans. Several dinosaurs have been found with good
> >sterna, BTW.
> O.K. If there is a pre-Archy dino that has a decent sternum, I'll
See another post I just sent. I think _Xuanhanosaurus_ shows a good
sternum, BTW, and I know many (most? all?) sauropodomorphs and
ornithischians have ossified sternal plates.
Pacific Lutheran University
Tacoma, WA 98447
"If you can't convince them, confuse them." -- Harry S Truman