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Re: [dinosaur] Jianianhualong, new feathered troodontid from Lower Cretaceous Jehol Group of China (free pdf)




On Thu, May 4th, 2017 at 5:08 PM, Tim Williams <tijawi@gmail.com> wrote:

> I agree that "asymmetrical" versus "symmetrical" should not be
> regarded as a binary character, since there are different kinds of
> "asymmetry".  And it's still not clear why vane asymmetry (functional
> asymmetry) evolved in the first place.  Was it originally associated
> with terrestrial 'pre-flight' behaviors (leaping, maneuverability,
> etc)?  Or was vane asymmetry originally involved in a non-locomotory
> function, such as display?

Could vein asymmetry have originally evolved to aid in folding the 'wing' fan? 
Ostriches appear to
have symmetrical feathers on most parts of their bodies, however some of their 
wing feathers
seem to be asymmetrical. Perhaps that helps the feathers to slide over each 
other when folding
or unfolding the forelimbs?

-- 
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 Dann Pigdon
 GIS Officer
 Melbourne, Australia
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