[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

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
> agree.

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.

> Rob

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447

"If you can't convince them, confuse them." -- Harry S Truman