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As Thom says here I'm working on re-reconstructing my own paintings
using the Longrich model... I don't regret that. This is the business
of having fun recognizing the fact of being obsolete in stages.
On the other hand, the leg 'wings' of Archaeopteryx are not at all as
extreme as Microraptor's virtually perfect "leg wing"... so evolution
could have favored the arm wings over the leg wings at other
stages... this mosaic evolution is shown all over the place in what
we know about bird evolution. What about the possibility that the
chicks did not develop the leg wings until later? They would be using
WAIR as a way to avoid predators.
I see the avian model as a half-running, half flying one.
Perfect functionalism is not a priority in evolution (as they say,
for us it is good to have the sophisticated eyes we have now, but
for other animals a few light-sensitive cells might have worked just
as well or better that if they didn't have them).
I don't think that >all< primitive "flying or gliding" theropods had
leg wings. I don't think they had to either... so I think we better
keep an open mind and see what the evidence and the next model built
on that will bring us.
On 25 Sep 2006, at 13:39, Thomas R. Holtz, Jr. wrote:
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]On
Robert J. Schenck
thought the Dial WAIR model was more widely
accepted and I definitively accept that model
much more than any of the others."
But the WAIR model is built upon two feathered
forelimgs, giving the organism a 'hold' to the
slopping/vertical running surfaces.
Is there are variation of WAIR that invovles the
leg feathers/leg wing?
Not as yet.
If WAIR is the activity
that most leads to flight in the evolution of
birds, it requires that the legs be powerfully
developed and devoted to running no?
Much as they are ancestrally, yes, yes it would. I.e., it requires
them to have theropod legs. Which they do.
variations away from that, while still in the
"WAIR Stage" would be deleterious to the organism
no, it would interfere with WAIR no?
No. They wouldn't. I really wish people would get over this idea!!!
They would presumably interfere with the rapid flexion and
extension of the hindlimb much the way that the longer flight
modern birds prevent the rapid opening and closure of wings: i.e.,
not at all!
course, hindlimbs with flight feathers evolved
after the "WAIR stage" of course.
Plus, you should probably hope that Mr. Longrich
is wrong no? YOu'll have to redo all those
fascinating paintings, adding wing-legs!
Oh, he's woking on that!!
Thomas R. Holtz, Jr.
Senior Lecturer, Vertebrate Paleontology
Department of Geology Director, Earth, Life & Time Program
University of Maryland College Park Scholars
Building 237, Room 1117
College Park, MD 20742
Phone: 301-405-4084 Email: firstname.lastname@example.org
Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796
Visit my website
- From: "Thomas R. Holtz, Jr." <email@example.com>