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Re: Origin of feathers

<< Name me a bird that broods with feathers on the lateral surface of 
the body. While not disparaging the idea that yes, the brooder could 
have had brooding feathers on the sides, it is not unpresumptuous to say 
that yes, there could have been brachial feathers long enough to brood 
with, and even not interfere with the other manual or brachial motions 
of the arms. >>

<You're missing my point here.>

  Perhaps. I think I may have been a little testy when I wrote this (not 
at you, or anything on the list, a perfect example of letting my life in 
the back door).

<I would assert that there are no lateral brooding-feathers in birds 
because they make use of the feathers that appeared on their forelimbs 
for reasons other than brooding. When you assert that feathers appeared 
in birds >for brooding eggs<,>

  I didn't say that. I was actually agreeing with you. I went on to say 
that feather evolution as functional flight may have been exapted for 
the brooding method in *Oviraptor*.

<you haven't explained why they would appear preferentially on the 
forelimbs and not somewhere else, such as the sides of the bird or the 
back, etc. You need to come up with something about the forelimbs that 
would compel the evolution specifically of brooding-feathers there, to 
the exclusion of other parts of the body.>

  I would assume they would appear on the forelimbs because Ovi's 
ansectors had them, albeit being a little smaller, having a smaller 
brood to care for, even a single egg. Those wings of Archie sure would 
make excellent sunshades :-) If anything, the posture of the brooder 
actually agrees with BCF, wouldn't you concur? And if feathers appeared 
on the forelimbs, long and secondary-like, why not? Of course, why?

  Hot sun, for one, and the environment wasn't to moist. Ostriches 
"parasol" their wings over both egg and chick, as do rheas and emus; 
cassowaries, being tropical jungle dwellers, just build mounds of dirt 
and sit around all day. These wings (or should I say, feathers?) have 
stuck around, even with the flight capability gone. I'm just saying that 
Ovi suggests this as well.

<< Many birds can adjust their feathers so they do not stick out, lay 
flat, etc. The ventral surface of the avian ulna is ridged, while 
*Oviraptor*'s (for instance) is not, and we already assume Archie could 
use his claws and fly (or ornithopt, or whatever). The ridge actually 
stiffens the quills, while a rounded surface would not provide any 
direct anchor for the ends. Thus, we can assume that a brooding dinosaur 
could actually tuck its feathers parallel to the arm, and never 
interfere with the manual motions. >>

<This is actually a pretty strong argument against the existence of 
>any< sizable wing feathers on the forelimbs of _Oviraptor_. Perhaps we 
should consider whether _Oviraptor_ retained any feathers at all, let 
alone elongate brooding-feathers of some kind. Perhaps _Sinosauropteryx_ 
fuzz is all the feathers _Oviraptor_ had, too.>

  If this _is_ so, how do we then look at the arm posture? This could 
have been taphonomical, but when we see this, and compare to a bird 
brooding, we are instantly astounded. The AMNH sure was. The 
similarities are just staggering.

  Now, aside from the visually-blinding standpoint, could we assume that 
yes, long feathers existed on the arms, long enough to cover the spaces 
between arms and feet where eggs are exposed? Fuzz, or bare skin would 
not do the job, as exciting an idea it might actually be. 
*Sinosauropteryx*, for instance, may have used his fuzz (quite long on 
the sides and arms) to maximize the lateral plan of coverage. Later on, 
Archie has feathers, and his sister group gives rise to oviraptors, and 
they retain the [Archaeopteryx + Oviraptor] arm feathers.

  Anyway, the Djadochta doesn't seem to be very good at preserving 
impressions, such as Santana, Solnhofen, Las Hoyas, or Yixian beds. We 
may have to wait a while to see the evidence for, and if it doesn't 
appear, that could mean it may not exist.

  I don't disagree with you, George.

Jaime A. Headden

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