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RE: Who says dromaeosaurs can't fly?




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Jaime A. Headden
Sent: Thursday, September 12, 2002 9:07 PM
To: dinosaur@usc.edu
Cc: GSP1954@aol.com
Subject: Re: Who says dromaeosaurs can't fly?

Greg Paul (GSP1954@aol.com) wrote:

<Everyone get used to it. At least some basal dromaeosaurs could fly baby,
and better than Archaeopteryx. In no way was Crypto a protoflier, it was a
fully developed flier whose performance approached and equalled that of
pterosaurs and confusiusornithids that lack deep keeled sterna but have
well developed wings. The dromaeosaur should have been able to take off
from level ground, climb and fly a substantial distance, and land high in
a try. It may have used flight as a regular attack mode. Imagine
sickle-claws perched high in trees, waiting for some hapless prey to walk
through the neighboring glade only to be pounced upon from above!
Screaming dinosaurs from the air! (Research into stomach contents
indicates that cladists were considered especially tasty). Since the Jehol
is churning out fossils like candy out of a Hershey factory we will get
more and more fossils that will only make this increasingly clear, so
there is no point making a fuss about it. You don't want to be like those
who went on and on about how dinos don't have feathers and those fibers
are really just frayed collagon, now do you? If you do, the burden is upon
you to demonstrate that Cryptovolans was not a competent flier.

 Readjust your minds to the new reality.>

I agree 100% with Greg (as you can see in my other posts).


>>  I'd hate to think what this statement may imply, on the nature of people
trying to _not_ accept volant dromaeosaurids. The converse is true, as
made from statements on this list. Some individuals appear to think the
multitude of us are arranged against the "truth."<<

You know, I grow werry of this argument. People keep saying we don't
disagree with the 'possiblity' but then argue completely against a flying
dromaeosaur. 'They' have this dogmatic view, that just won't change. These
arguments just help Feduccia and Martin. To many are just way TOO consertive
for my tastes.

>>The basal fellows, like *Sinovenator*, *Microraptor*, and
*Sinornithosaurus*, have large arms, large shoulders with reflexed
coracoids, and large sterna. What they do not have are true pinnate
feathers. From the photos I've seen of *Cryptovolans*, the feathers lack
barbules, and would not have been very aerodynamic in this feature.<<

Are they preserved well enough that you could see them? Give me a break on
that statement.

>>  The argument that any vaguely dromie animal is a dromaeosaur must depend
on some sort of phylogenetic concept for the word/term "dromaeosaur"; if
in generalities *Cryptovolans* is a "dromie," then fine, but it is not a
dromaeosaurid (member of clade Dromaeosauridae), I can assure you.<<

In your view, correct? Not mine.

>> And in an argument such as this, semantics is king.<<

Then who's right? (Me of course :) ).

>> You _must_ argue the particulars and not the generalities to assess the
nature of something or
an approximation of it. Flight is a biomechanical issue, not a typological
one, and assessing an animals flight performance by feather type, size,
mass, and arm size, means nothing, in this respect; it has to be
demonstrated the mechanisms under which flight can be acheived, and the
dynamics to which feathers and therefore a wing can perform
aerodynamically.<<

Again, we have to STOP thinking of what flying was, not what flying is
today. It's like banging my head against the wall.

>> An ostrich has long arm feathers, as do "weak" fliers
like tinamous, woodcocks, and kagus. The emu has the most mechanically
"wing-like" arm structure of any ratites, and proportionately the longest
wings, but as a ratite it is fairly advanced compared to the moa-kiwi
clade, which have virtually no arm skeleton. The effects of paedomorphosis
have been invoked for some aspects of paleognath and neognath evolution,
but they have not been strongly applied to the origin of flight; indeed,
until the "Farlow and the dark side" paper on *Caudipteryx* and limb
proportions with Terry Jones et al., the question of paedomorphosis in the
evolution of the avian hindlimb has not been broached strongly, and is an
aspect that some researchers are exploring ...

  ... but we ain't there yet, folks. Nothing stops us from speculating,
but nothing _is_, and especially with paleontology, "there are no
absolutes."<<

You know, reading this list, I don't think we ever will be...

  Cheers,

=====
Jaime A. Headden

Tracy L. Ford
P. O. Box 1171
Poway Ca  92074