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RE: You have got to be kidding (Re: Nudds and Dyke)
So, Nudds and Dyke don't cit GSP, which is not okay even though GSP didn't cite
Nudds and Dyke when discussing a topic on which they'd directly published, in a
well-publicized paper, no less?
Also, forgive me if I am wrong, but the main issues here are 1) Meaning of
powered flight, 2) Relative performance of Archie and Confu to extant birds,
and 3) what features in extant birds are actually related to "powered flight?"
GSP wrote (_Dinosaurs of the Air_, pg. 154) that "*Archaeopteryx* is an obvious
example of information about the kind of characters expected to be associated
with flight loss in the early stages, but some predictions about what we should
expect in slighltly less advanced or somewhat more advanced fliers are
necessary. The most obvious potentially neoflightless characters center on the
asaptations that made the shoulder girdle suitable as a base for wings[.] The
potentially flightneoflightless characters associated with the arm are more
limited be3cause this appendgae is remarkably little modified from the
predatory dinosaur condition in *Archaeopteryx.* [...] For example, ossified
uncinate processes may have strengthened the rib cage or aided respiration or
both." (Quote mining mine.)
Note that no specimen of *Archaeopteryx* has uncinate processes on the ribs.
Paul further discusses characters that should indicate neoflightlessness (Pg.
155). 40 in total, most authors have typically indicated these features
indicate FLIGHT, rather than its loss. Determination of the flight ability of
these features from their presence alone is unclear, but it is assumed that the
animal otherwise being considered must already seem to be flightless in the
first place. This forms the basis of Paul's theory that dromaeosaurids derive
from an *Archaeopteryx*-like taxon and were originally volant. The premise
should, however, not distinguish *Archaeopteryx* from *Velociraptor*, wings and
feathers or not. So it makes it unclear where Paul draws the line.
In most lay usage, the definition for "powered flight" is commonly associated
with modern avian flying; various authors have already argued, on the basis of
various lines of evidence, that using modern avian flight capability and
extrapolating various elements and landmarks onto *Archaeopteryx* renders its
potential performance output lower than that of modern birds. Nudds and Dyke
are only the latest piece to show *Archaeopteryx* -- surprisingly -- is not a
modern bird. So when we discuss the idea that *Archaeopteryx* has a weaker
flight module than modern birds, we simply downgrade (in the common usage) the
performance angle -- but still keep the powered flight concept so that this
"clearly adapted flier" may remain as such (I'm not quoting anyone in
particular). In relation to this problem, Paul continues to discuss
*Archaeopteryx*, the loss of flight, the presence of features that indicate
loss of flight (but these are actually all features that indicate improved arm
performance, respiration etc. in the taxa that have them), but does not show
that the argument can give us a limit on how many features must not be present
to make a taxon "neoflightless" -- and this especially applies to
Despite applying the model to *Archaeopteryx,* the taxon is shown as a
reasonably capable flier, and this belies the importance of such features in a
study by phenetic mapping: Authors (not just GSP) have a tendency to list a
host of features, indicate their value, and transfer their expectations of said
taxon onto those features, permitting them to use said features to indicate
something they originally premised otherwise. So if the features of
*Archaeopteryx* are traits we find in non-flying dinosaurs, then why isn't
*Archaeopteryx* also a non-flying dinosaur?
However, previously, as I said, I wrote thet Nudds and Dyke are only adding
data points to the larger discussion, and while the data points to lack of
derived flight ability in Archie, it does not remove ANY volant capability from
Archie. Many authors have shown derived aerodynamic qualities of the wing and
tail, but few (by which I mean either none or none that I know of) have been
able to directly map the threshhold at which the skeletal features transcend
flightlessness to flightedness.
Jaime A. Headden
The Bite Stuff (site v2)
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion
> Date: Fri, 14 May 2010 22:31:31 -0400
> From: GSP1954@aol.com
> To: Dinosaur@usc.edu; Vrtpaleo@usc.edu
> Subject: You have got to be kidding
> The Nudds & Dyke paper in Science on the supposedly weak feathers of
> Archaeopteryx and Confuciusornis is wrong, wrong, wrong. They failed to do a
> proper literature search on a key factor in their calculations, and the exact
> reason they are way into wrong is in Dinosaurs of the Air (which they did not
> cite) if you know where to look. Am not going to say where they made their
> critical mistake because am going to send in a technical comment to Science.
> There is no evidence based on feather dimensions that basal birds could not
> power fly.
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