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



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.


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