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Re: feathers



Earl Wood wrote:
<Hello , I  have been monitoring the list about feathers , and I
would like some comment on the following to see if it is of any 
value.......

   I think that perhaps a small dinosaur found a nitch as a predator
of small fish......>

  It would seem that *Ornitholestes* and *Proceratosaurus* and even the 
compsognathids had some piscivorous traits, which would include long 
neck, long teeth anteriorly, and the mandible with teeth curved 
downward, the premaxillary teeth lengthened to accomodate. One could 
assume that these adaptations, seen in all taxa named, could be used for 
eating fish. Also, the hands are not as specialized as later 
oviraptorosaurs and/or therizinosauroids, and were more or less of 
unequal lengths, good for catching things with, where the fingers would 
splay out in a triangual patter evenly, and not with digits III and II 
of equal lengths, seen in dromaeosaurs and oviraptorosaurs (excluding 
*Ingenia*) and therizinosauroids.

<That in that capacity it would develop hollow bones for flotation
purposes......>

  The hollow bones go all the way back to the Triassic. Now, this is not 
to say *Herrerasaurus* couldn't catch the occasional fish, and the same 
for *Eoraptor*. The hollowness, though, increased agility for it reduced 
weight. It might even have been a co-culprit of bipedality, one causing 
the other (they evolved in tandem for the same reason, in other words).

<Arms would evolve into longer appendages to aid in pushing for
greater speed....

As perhaps the earth cooled prior to the K/T boundary the need for
greater insulation as well as more buoyancy was needed which brought 
about proto feathers which were only a modification of the scales to a 
hollow tubule........>

  We see this from Coelurosauria on, and indeed, except for tyrannosaurs 
and compsognathids, all arm characters seem to gear towards increased 
mobility with the forelimbs (fore, aft, sidewise, downward, inward, and 
even upward). And integument as protofeathers seem to have popped up 
from Compsognathidae (including *Sinosauropteryx*) and passed down the 
line, though sino represent a possible unique case, or a rather ordinary 
one, and like Peter Buchholz wrote a few days ago, _all_ theropods could 
have had non-scaly integument, and protofeathers isn't a bad way to go 
unless your climate prevents it.

  Now, cooling of the earth may be the culprit for formation of feathers 
as we know them, but this would go all the way back to *Archaeopteryx'* 
ancestors, and and at that time (Late Jurassic) the Earth was not so 
cool.

  Another remark: present day birds will actually _lose_ feathers in 
hotter climates, or at least the ratites did so, but otherwise feathers 
appear on hot-climate birds and cold-climate birds, and the same types 
of feathers and birds (penguins are, of course, the exception).

<From there it would seem to me that the need for more speed and
stronger arms would lead to eventual flight as an aquatic bird.>

  All birds who are primarily swimmers ano/or fishers, such as 
flightless cormorants and auks, and penguins of course, have smaller arm 
feathers, in need of less drag. The same strength is implied for aquatic 
or aerial flight.

  And now I am touching on another topic, so I'd better quite while I'm 
behind :)

  Otherwise, Earl Wood, you've given a good premise, and it deserves 
looking in to.

  Jaime A. Headden

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