Re: Pterosaur and bat wing shapes (was: feather symmmetry)

[Ronald Orenstein <ornstn@rogers.com>]

At 04:03 PM 12/09/02 -0700, longrich@alumni.princeton.edu wrote:
> Another interesting thing with respect to flying vertebrates... I was 
> looking at some molossid bat skins recently, they are very cool. Molossids 
> have extremely long, narrow wings and apparently use speed more than 
> maneuverability to catch insects. Interestingly, in the particular 
> specimens I was looking at, the wing membrane ends roughly at the knee! 
> Anyways its sort of interesting re: the "knee vs. ankle" argument on 
> pterosaurs... either reconstruction of the wing membrane is arguably 
> "batlike" depending on which bats you are talking about, and naturally its 
> quite possible that multiple different arrangements existed in the diverse 
> pterosaurs. Uropatagia are also structurally very diverse in bats.

I had a very good demonstration of the difference this makes many years ago 
in Costa Rica, on an Organization for Tropical Studies field course.  I was 
involved in an all-night bat-netting session during which we captured a 
number of species, and made wing-tracings of the lot.  Wing-shape is indeed 
very diverse in bats, with the molossids as one extreme.  A consequence of 
this was that when other bats weer released, they flew off easily - but 
Molossus that we caught could not take off even if tossed in the air.  The 
only way we could release them was by placing them on a tree trunk.  From 
here they scuttled upwards some thirty feet or so before launching 
themselves successfully.

I have always assumed that it was most unlikely that all pterosaur wing 
shapes were the same, any more than bat wing shapes are.  In fact, for 
niche separation in a pterosaur community it would be expected that 
wing-shape would vary, with long, narrow wings in some species (perhaps 
those flying over forest canopies or launching themselves over the sea from 
cliff, short broad wings in others flying among tree trunks below the 
canopy, etc.


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@rogers.com