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Re: The dino-bird connection revisited

On Mon, 19 Feb 1996, King, Norm wrote:

> If _Protoavis_ did, and _Archeopteryx_ did not, might that suggest that 
> _Archeopteryx_ is a flying theropod rather than a flying bird?  That 
> would surely explain why _Archeopteryx_ plots out very close to 
> theropods.

Well...  Yes. But if _Archaeopteryx_ is a "flying theropod," then the 
very similar _Confuciusornis_ and _Sinornis_ are, too.  And if THEY are 
theropods (and not birds), then the same is true of _Concornis_, 
Iberomesornis_, _Ambiortus_, and the enantiornithians.  I think you can 
see where I'm going with this one.

Suffice it to say, nowadays we really have a pretty good morphological 
sequence of fairly well-preserved animals linking _Archaeopteryx_ 
securely with the modern birds.  Hence, if _Archaeopteryx_ was not a 
bird, then neither is a house sparrow.

> What is a bird, really?  Can skeletal features provide a 
> characterization, since feathers normally won't be preserved?  

Certainly.  Birds are fairly unusual critters.  And practically every 
skeletal peculiarity in birds can be traced to non-avian dinosaurs.

> Of course, if we assume that _Archeopteryx_ is a bird, that really stacks 
> the deck in favor of maniraptoran ancestors for birds.  What should I 
> know that would show me why the claim of theropod ancestry for birds is 
> not this transparently circular?

Non-archaeopterygian birds also show distinctly maniraptoran characters, 
including the carpal block, deep coracoids, large sterna, and the form of 
the hand.  I particularly like the illo by Bakker in _The Dinosaur 
Heresies_ of the hands of a hoatzin hatchling, _Archaeopteryx_, and 
_Deinonychus_.  Wow.  Check it out.

> *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
> Norman R. King                                       tel:  (812) 464-1794

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447

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