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Re: MORE FEATHERS & NEKKID MAMMALS
Peter Buchholz wrote:
>Because, as we understand dinosaur systematics at this moment in time
>TYRANNOSAURS ARE CLOSER TO BIRDS THAN ARE COMPSOGNATHIDS. Period.
>Tyrannosaurs fall with in the clade Coelurosauria (Compsognathus + Corvis),
>and so, therefore had the potential to be feathered.
I still don't understand how feathers are reconciled with a scaley
skin. Regardless of whether birds are born feathered or naked, they at
some point get feathers on the smooth skin and scales everywhere else.
This implies something about the incompatability of feathers and scales
on the same section of skin. If you are growing feathers somewhere, you
don't want scales there. For theropods with scaley skin impressions, this
implies one of two things:
1) They were scaled thier entire lives.
2) At some point, they altered the fundamental nature of thier
skin. How could this be accomplished? Do birds regularly shed thier
skin? This cannot be a case of "ontongeny recapitu
Tyrannosaur scales might only be known from small patches, but to my
knowledge none of these patches come from the legs or face. If
tyrannosaurs fall within the new phylogenetic bracket made by
_Sinosauropteryx_, the integumentory presence of scales is even more
difficult to understand.
What sort of work is availible on the compositional differences of
bird and reptile skin?
Also, would anyone care to explain why so few endothermic animals
are poisionous, when such a huge percentage of ectotherms are?