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RE: vaulting pterosaur launch, questions
David Marjanovic wrote:
>> Even the brooding hypothesis (which I like) doesn't explain why the
>> feathers of _Archaeopteryx_ were asymmetrical,
> It does, or at least it claims to do: the leading edge is more likely to
> contact the ground.
Hmm... do you really 'buy' that explanation?
> It also explains very nicely why tertials aren't remiges (not even in
> soaring birds with endless humeri) and why Archie lacks them altogether.
Not necessarily - especially if the emphasis is on maneuverability during the
descent. Sure, mammalian gliders and many reptilian ones (like _Draco_ and
kuehneosaurs) have a continuous lift surface that connects the body wall to the
limbs. But the distal gliding surfaces (webbed feet) of "flying" frogs
(_Rhacophorus_, etc) and "flying" lizards (_Ptychozoon_) accord a great deal of
benefit in gliding. True, in _Ptychozoon_ the cutaneous flaps play a role too;
but those big webbed feet improve both the lift:drag ratio and maneuverability.
> That doesn't mean we can't do science on this question. Had Archie been a
> glider, it would almost certainly have had tertials...
This is what the "Pouncing Proavis" hypothesis states. However, the lack of
tertials in _Archaeopteryx_ does not necessarily mean it didn't glide, nor that
its ancestors didn't either.
>> nor why the tail was lined with rectrices.
> Indeed not, but for this you can always blame sexual selection :o)
Oh, you mean "display". When there's no other explanation, then it must be
Garner, J.P., Taylor, G.K., and Thomas, A.L.R. (1999). On the origins of
birds: The sequence of character acquisition in the evolution of avian flight.
Proc. Biol. Sci. 266: 1259-1266.
Young, B.A., Lee, C.A., and Daley, K.M. (2002). On a flap and a foot: Aerial
locomotion in the "flying" gecko, _Ptychozoon kuhli_. J. Herpetology 36:
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