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RE: vaulting pterosaur launch, questions




Scott Hartman wrote:


> That presumes, of course, that Archaeopteryx got airborne for any
> significant period of time at all. It continues to amaze me how we can
> have discussions using Archaeopteryx as the pivot point for "origin of
> flight" discussions when it hasn't been properly established that
> Archaeopteryx flew, or if so, how, when, where, and why?


True - on all accounts.  Nevertheless, _Archaeopteryx_ did have wings, and in 
all likelihood it was using those wings for *something*.  That *something* was 
probably some form of aerial locomotion.  That at least is the most 
parsimonious explanation, given that this is what modern birds use their wings 
for.  (Well, most of them, anyway.)   I think we've moved away from unorthodox 
views which held that the wings of _Archaeopteryx_ were *not* flight-related, 
but were instead used purely for a non-aerodynamic function (such as 
insect-nets, or to shade the water while hunting fish).  Even the brooding 
hypothesis (which I like) doesn't explain why the feathers of _Archaeopteryx_ 
were asymmetrical, nor why the tail was lined with rectrices.


I also agree that _Archaeopteryx_ has been regarded as being a "pivot point" 
for the origin of flight, insofar as its inferred ecology might give us clues 
to the origin of avian flight.  This assumption may be dead wrong.  
_Archaeopteryx_ might actually lie a long way (both phylogenetically and 
ecomorphologically) from the origin of flight of theropods.  There is a 
minority view that the poor flight abilities of _Archaeopteryx_ were secondary, 
and associated with its island-dwelling habitat.  If so, the first flying 
theropod might have actually looked nothing like _Archaeoptyeryx_.  


However, the available evidence (such as it is) does point to _Archaeopteryx_ 
being fairly close to the origin of flight, even if it wasn't directly 
ancestral to later birds.  As to whether it was a glider, a sustained flier, or 
something in between - of course, we'll never *know*.  But I think it's a real 
stretch to say that that _Archaeopteryx_ did *not* use its wings for aerial 
locomotion.  And if it did use its wings for aerial locomotion, then it needed 
some way to get into the air.  


Cheers

Tim





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