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RE: Sinosauropteryx feathers?
Ok... First off, I wasn't looking for a slap to the face here. Secondly, the
only reason I said what I said was to take a break from getting ready for
finals by having some fun imaginative speculations, and to offer Mr. Lovejoy a
response to his post. I know what it's like to have your posts ignored. Looks
like I was very, very successful in my endeavor. Thirdly, Iâm not going to
get into a brawl over this, so the below is all I am going to say.....
Of course I know about what you said Mr. Headden. Old news really... and as in
an article entitled "The morphogenesis of feathers" in 30 October 2002 Nature
pretty much adequately demonstrated via developmental approaches, that the
barbs to rachis model is the one that best fits the data. Barbs form first in
development and thus in integument evolution, with rachis, a special form of
fused barbs, appearing later as an evolutionary novelty. I know this. Oh, and
you said "... those of *Sinosauropteryx* are stage II structures where various
filaments fuse at the base, but in a fan-shaped structure with a possible
helical base order. No other structures aside from single filaments (stage I)
have been described for *Sinosauropteryx*..." Which is it then? "Stage I" or
"Stage II"? I thought that there was a combination of both observed for the
little guy anyway. In fact, my understanding is that this is the case for ALL
feathered theropods... combinations of feather forms... just l!
e birds now. Funny how that is.. Also, your "Stages" refer to Prum and Brush's
work right? I only ask since I sat in on a talk at SVP by Hillenius and
Maderson about how some of these hypothetical neomorphic developmental "Stages"
are not congruent with the developmental genetics. I think it was with those
beyond "Stage II" where problems arise... Something about tissue distributions
and keratin types... a morphological "jump" that is not possible... misleading
notions about developing feather shape and form... or something to that effect.
Baer's Law might have had something to do with it too. All I know is that the
talk asserted that Prum and Brush's model is supposedly lacking in the
developmental, morphological and molecular data department. I don't remember
for sure, and I only have the notes I took from the talk at my disposal. But
this is beside the point.
The actual point is, what I place on the skin of *Sinosauropteryx* isn't really
an issue, and I don't want to make one of it. Feathers apparently are a derived
novelty, whose evolution themselves constituted numerous morphological and
developmental novelties. Feathers evolved and diversified before the evolution
of what we now like to label and neatly categorize as the birds. Feathers
evolving solely for the purpose of flight has been falsified. And as I
understand it, learning from the talk at SVP, there is no phylogenetics that
gives you a phylogenetic analysis of feather evolution. Modern birds show no
"primitive to advanced" feather pattern. Why insinuate that this was NOT the
case for extinct theropods? This is like saying beaks, being what beaks are,
belong solely to the birds. As some people seem to think, "Teeth and a beak you
say!!?? How dare you Sr!!!??? Never!!!!!!!"... So why is it that some of those
"phylogenetically primitive" dinosaurs possessed beaks and even!
eaks also with teeth? I think all of this is just another good example as to
why I tend to view cladistics in the same light as Mr. Paul. In all, I perceive
cladistic arguments as the corollary evidence in this type of arena as being
very inadequate and misleading.
I see that *Sinosauropteryx* is only preserved with filaments of one sort or
another... I'm not blind... But this doesn't mean for an unquestionable fact
that this is all that it ever had, no matter what the opinion is on what's
direct evidence to the contrary or not. In fact, there were more species of
ceolurosaurs than just *Sinosauropteryx*, and there is such a thing called
variation. I wonder if a MALE bird of paradise was to be fossilized, would
those radically wild display plumes hidden deep beneath their regular old
plumage be clearly preserved? Would we ever find the bird to begin with? My
best educated guesses are "No"... and "No" again. And for another twist, what
happens if we just find FEMALES? Does this mean a verified and unquestionable
"No" to display feathers for the entire species? Also, arguments about how
feathers with rachis are only associated with the advent/loss of flight simply
holds not a drop of water for me. My understanding is that structures don'!
simply evolve for only one, single purpose. Evolution has the funny habit of
not proceeding in the nice, logical, orderly fashion that many want it to
proceed in. Helps with categorizing and labeling I suppose. It bugs me when
people try to force evolution onto a tidy, neat, perfectly predictable path. I
mean really... Look at the trouble such thinking has gotten the human evolution
folks into. And by the way, donât you need feathers of the lifting sort, be
them asymmetrical or not, to evolve first before you take to the skies to begin
with??? Who evolved them first??? What group had them??? Since evolution has no
directed goal, what was the pre-flight advantage for the continuous evolution
of such feathers??? What was being selected for??? Whatâs the distribution to
the mix of feather types across the Dinosauria??? Was it only one, strictly
defined group and their descendents who were magically bestowed one day with
the special rachis honors??? Are these types of feathe!
only reserved for dromaeosaurs now??? Were we thinking t!
dromaeosaurs didnât have these types of feathers before *Cryptovolans* was
found??? Or is it that these feathers are still only for the birds since we
still are of the opinion that dromaeosaurs didnât fly??? If the later is the
case, then what does this make *Cryptovolans* out to be??? Does the flyer make
the bird who cladistically dictates who has the type of feathers??? Iâm not
asking for answers to these questions. Iâm not picking a fight here. I simply
do not see things in a palate of strict black and white until it becomes
perfectly clear that this happens to be the case. But when it comes to
evolution, it never is black and white case. This is all I am saying. But then
again, I can't say anything for sure now can I? I do not possess an all seeing
and all knowing eye that allows me to pound my fists on the table and proclaim
to the heavens that this is how it is and how it is going to be. I know of no
one who does.
By the way, Mr. Lovejoy, I have Prum and Brush's paper on feather
diversification and evolution from the Sept 2002 "Quaterly Review of Biology"
along with the "Nature" paper I mentioned from October 2002 in .pdf form. They
have numerous graphics I'm sure you'd be interested in seeing. They also
attempt to answer some of those questions you asked in your last post. If ya
want them, just drop me an e-mail.