Wings and Such

[Stang1996@aol.com]

    Another thing that's always troubled me about the "traditional model" of
pterosaurs with their legs in their wings is: what the hell good is a leg in
a wing?
    Again, using "The Illustrated Encyclopaedia of Pterosaurs" we see that
the figure labelled 'Wing Movements' on page 153 shows a pterosaur's wing
movements (hence the name) from up-stroke to down-stroke from a head-on
perspective.  In this diagram Wellnhoffer (surprisingly) doesn't put the
hind-limb "in" the wing.  I think it would have been very silly looking if he
did.  He shows the maximum up-stroke of the humerus to be about 75-85 deg.
    Now if the leg was in the wing, the femur would have had to have a _VERY_
mobile articulation with the acetebelum so as to get it pointed up in the air
75 deg. (hell, it would need one if it wanted to get it -5 deg!).  Correct me
if I'm wrong, but anything like that in ANY tetrapod's acetebelum equals
dislocation.
    Either that, or the legs just sat where they were (a neutral -45 to -85
deg) durring the up-stroke.  Now I'm no aeronautical engineer, but doesn't
that seem just a little aeronautically unsound?  It would be like having the
aerolons or elivators (or both) on an airplane be pointed down (so as to make
the plane go down) while the pilot (and pterosaur) are trying to make it go
up.  The upstroke is probably where flying animals loose a deal of altitude,
wouldn't the downwardly pointed legs (aerolons) loose them even more?
    Even more so, what good is a leg in the middle of an airfoil?  In a wing
on an airplane, wouldn't a lateral (or whatever apropriate adjective is to be
used; I hate zoolo-lingo) tube seriously affect the lift potential and the
aerodynamics of said wing?  This would be the same sort of thing for a
pterosaur that was gliding.  What evolutionary advantage would there be in
loosing a great deal of usable wing space?
    About bipedalism....  I do think that most pterosaurs, while on the
ground spent a lot of time on all fours, but probably moved around in a sort
of bipedal waddle.  I also believe that they could run sort-of OK, but hey,
why run when you can fly away?
    About pterosaur hands....  I have been wondering this for a while.  Is
the wing finger really digit four?  If it is, that would seem to me a very
aquard way of evolving.  Think about it.  On a five fingered animal (such as
yourself), why would digit four (your ring finger) become the elongate
leading edge of a wing membrane?  Why not digit five; the one closest to the
wing?  And the pteroid bone.  Does anyone really know what this was before it
was a pteroid bone?  Was it a complex of wrist bones that got themselves
migrated out of the wrist, or is it the remains of digit one?

Peter Buchholz
Stang1996@aol.com