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RE: Feduccia (was: polarity of bipedality in dinosaurs)



Norm King wrote:

>    As I recall, one of the big problems with the ground up theory is
>that Archaeopteryx's pectoralis muscles were too weak to provide the
>extra power needed for a ground take off, so it had to jump out of
>trees.
>     How valid is this, and how does the ground take off capabilities
>for pterosaurs (particularly the earlier ones) compare?

   And further, how does Confuci-etc's muscle development compare to   
Archie's?  Is it a parallel development where the pectoralis would be   
similar in both; is Archie more developed than Confuc-etc; or is   
Confuc-etc more developed (and thus, supposedly a better flier) than   
Archie?  Is there enough of Protoavis to determine if HE was better or   
worse than either?
   Since Archie is now only one of several types of early birds, is there   
enough to compare them to each other, as opposed to modern birds?  How do   
the pubis compare to each other?  Can we tell if at rest, some were   
setters (like ducks) and some were perchers (like song birds)?  How do   
the lengths of the tails compare to each other?  Are some of these early   
bird types more developed in this tail region (and thus muscular) than   
others?  Are these the earlier forms or not?
How does one tell if a change is an 'advanced characteristic' if it's a   
transition between two distinct types?  Only by the end results?  If   
having a well-developed butt is advanced in therapods but not in birds,   
is losing it advanced or not?

 -Betty Cunningham