Re: L'origine et l'évolution des oiseaux, with a

[Tim Williams <tijawi@yahoo.com>]

David Peters wrote:


> The key to this thread is long legs (longer tibia
> than femur) = cursor.


Refer to (and I guess you've already seen it, but it can't hurt to look again):


Dyke, G.J., Nudds, R.L. and Rayner, J.M.V. (2006). Flight of _Sharovipteryx 
mirabilis_: the world's first delta-winged glider.  J. Evol. Biol. 19: 
1040-1043.


If the length of the femur is functionally constrained (especially if wing 
shape is governed by femoral protraction, as Dyke &c propose), then increased 
length of the wing could only be achieved by elongation of the lower hindlimb.  
Under this scenario, the intramembral proportions of _Sharovipteryx's_ hindlimb 
have nothing to do with bipedal/terrestrial locomotion, but are an adaptation 
to gliding.



Cheers

Tim