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Re: Sinocalliopteryx (Theropoda: Compsognathidae) ate confuciusornithids and dromaeosaurids



GSPaul wrote:

it is very unlikely that the basal fliers could elevate the humerus to vertical 
the way birds can (I sometimes show the arm vertically
elevated in basal flier skeletals just to show the wing profile). Extremely 
unlikely they could take off vertically, but with a jumping-running start
may have been able to take off from the ground. Or maybe not. 

I agree that basal paravians probably could not elevate their humeri to the 
vertical.

But I hope that all readers will recall that experimental evidence shows that 
bats and surgically altered starlings can take off and fly well even when 
elevating their humeri only to a maximum of 50 degrees above horizontal 
(Sokoloff et al. 2001, and Bullen and McKenzie 2002). Thus the lack of a 
glenoid with the range of motion of modern birds should not be assumed by any 
reader to imply proof of flightlessness.

I also agree that the contribution of jumping to takeoff is huge, far more than 
I would have thought before I read the literature.