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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 Behalf Of
Robert J. Schenck

Mr. Rey
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!!! (Colleagues included!)

They would presumably interfere with the rapid flexion and extension of the hindlimb much the way that the longer flight feathers of
modern birds prevent the rapid opening and closure of wings: i.e., not at all!

Perhaps, of
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
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796

Luis Rey

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