Re: Folding Feathers Out of the Way

[TomHopp@aol.com]

James Headden wrote:

<< If they sported feathers and climbed, how would they have kept from 
damaging the feathers while climbing? That was the bulk of the hypothesis. 
You can test this in a multitude of ways, but to Rob Gay's observation, the 
vultures were not standing on their own feathers, so were not willingly doing 
anything to damage them. 
    how these feathers orient to the arm is a question that will go towards 
testing the original question, and perhaps the feathers would never have been 
in danger during climbing, or they would have folded relative to the long 
bones of the arm, which as I understand it there is no correlate or structure 
to suggest this was possible in the avian or maniraptoran (sensu stricto) arm.
   Anybody have further comments? >>

Did I hear my name mentioned? I have a photo of a mother duck whose chicks 
are all over her primaries, making it hard for her to stand up after brooding 
them. There are lots of pressures shaping the feathers and arm bones of 
modern birds. The same may have been true for maniraptorans. I am fond of the 
idea that the folding of the modern bird wing was dictated back in the 
Mesozoic when cursorial mothers needed to manage their long brooding 
arm-feathers. Even the semilunate carpal makes sense, without needing flight, 
climbing, or predatory swipes. Just the requirement for getting the 
baby-covering devices stowed out of harm's way could have led to bird-shaped 
arm bones and feathers. This is all covered in detail with diagrams in Hopp 
and Orsen, Dinofest 98 (if the dang thing ever gets published).
- Tom Hopp
P.S. preprints available.