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Re: Primary feather stiffness in Mesozoic birds



On Jan 24, 2012, at 5:22 PM, Mike Keesey wrote:

>> WANG, X., NUDDS, R. L., PALMER, C. and DYKE, G. J. (2012)
>> Size scaling and stiffness of avian primary feathers: implications for
>> the flight of Mesozoic birds.
> [...]
>> Adding fossil measurement data to our DFA showed
>> that Archaeopteryx and Confuciusornis do not overlap with extant
>> birds. This strongly suggests that the bending stiffness of their
>> primary feathers was different to extant birds and provides further
>> evidence for distinctive flight styles and likely limited flight
>> ability in Archaeopteryx and Confuciusornis.
> 
> So ... were their feathers bendier or stiffer than modern bird
> feathers? (I don't have access to the paper.)


For Confuciusornis, the resultant discriminant analysis suggests that the 
feathers would be more compliant than a similarly sized modern bird (i.e. 
bendier).  However, the result for Archaeopteryx is less clear - it falls 
between two of their primary modern species clouds in discriminant space, but 
the result is not objectively "lower" or "higher".  It is simply sitting in a 
relatively unoccupied area of the components plot.  This is why the authors 
simply say "distinctive" rather than indicating a polarity.

Cheers,

--Mike H.


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181