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Re: Pterosaur wing membranes (Questions)



Nobody seems to have answered this...

----- Original Message -----
From: <paleo@ncf.ca>
Sent: Wednesday, October 20, 2004 3:39 PM

> It seems obvious that as a pterosaur grew and also as its wings took wear
> its wing membranes would have to grow.
>
> Is it assumed that they would continously grow out from the base or is
there
> much thought to the concept of growth in sections of the membrane itself?
> Or are we talking about a situation that involves... sheding??

The wing "membrane" consisted not just of a double layer of skin, but also
of strengthening fibers, blood vessels and muscle fibers in between. In
other words, it was living tissue that probably grew everywhere.

> It seems that there would be a use in being
> able to heal over extremely small tears or over stressed areas.

Holes in bat wings -- similar to pterosaur wings, but withoug the stiffening
fibers -- are said to heal extremely fast.

> If it is possible there was activity in the wing, what mechanisms would
one
> expect to control heat loss, especially in conditions that combine
moisture
> and strong winds.

I know too little about the aerodynamic effects of fur. In general,
pterosaur wings seem to have been naked -- judging from the very few fossils
that actually preserve sufficient details!

> I have seen pictures of a ramphorynchus specimen that appears to have
clear
> fan like folding mechanisms apparently radiating from near the base of the
> first phalange (much like the feather layout in a Gull except reversed).
> It seems to suggest that the wing membrane may have been much stiffer
> than is often depicted.

You are right. Modern depictions -- as opposed to those that were in the
literature 30 or more years ago and can still be found in popular books -- 
show quite stiff wings.