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Re: feathers, hair and Compsognathus



> REQUIRES that dinosaurs be considered unfeathered.  I would think we would
> look to the dinosaurs' closest living relatives for clues about their
> integument, and those living relatives are feathered ... therefore I would
> think the logical conclusion is dinosaurs ... at least theropods ... had
> feathers.

     Assuming that all details of dinosaur soft anatomy was identical to
birds is as illogical as assuming that thier osteology was identical.
There are a lot commonalitites, but thier osteology is not identical, so
why should we assume which details of theropod SOFT anatomy was shared
with birds?
     To give an analogy, one small branch of mammals, the primates,
re-evolved color vision.  Lets pretend for a moment that primates were
the only mammals left on earth.  A paleontologist might assume, using
reasoning similar to yours, that since the closest living relative of
extinct mammals were the living primates, that all mammals had color
vision, when in fact it was a useful innovation of one small group.
     [Note that I am not saying that assuming color vision in all
DINOSAURS is illogical.  Both living reptiles and birds have color vision,
so a phylogenetic bracket can be made.  However, since crocodilians don't
have feathers, and since the earliest known feather impressions are known only
from a couple small theropod dinosaurs, this sort of extrapolation cannot
be made for feathers (although it does tell us it was an archosaur
of some kind)].
      We just cannot say with any certainty for which common ancester of whom
among archosaurs feathers evolved.

> The few skin impressions we had up to this point were of the
> larger forms ... hadrosaurs, tyrannosaurs, etc. ... which, if TODAY'S large
> animals are any indication, would have lost most of their feathers just as
> elephants, rhinos, hippos and whales have lost most of their hair.

     On the places where birds have feathers, thier skin is relatively
smooth.  If I am not mistaken, on birds that have lost thier feathers in
some places (for example, the necks of living ratites), the skin there is
also smooth (the legs? on all birds retain the scales, indicating
that feathers were probably never present here). Birds being theropods after
all (if you choose to call them that), it would seem strange for a secondarily
naked skinned dinosaurs to have somehow reverted back to prominant scales
when a smooth skin seems to do the job just fine in nekkid birds.

LN Jeff
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