Re: Did pterosaurs feed by skimming?

[jrc <jrccea@bellsouth.net>]

> although Thalassodromeus and Tupuxuara score points for being more flexible 
> than most. Long-necked azhdarchids, by contrast, would've snapped their 
> necks the moment they skimmed anything with more resistance than snot, and 
> that's probably enough to shoot their skimming prospects down on its own.<

Physical manipulation of the skeleton of the quetz neck shows that it has 
enough ventral mobility to allow the jaw to tuck under and aft if an object 
is struck.  This will also sweep the wings slightly forward and the cg 
slightly aft, lifting the snout clear of the water.  And, you can see most 
objects in the water in time to avoid them anyway.  I've spent several 
hundred hours doing low level search and rescue flying in a Piper J3 on the 
Mississippi and White Rivers in the southern USA.  Even though the lower 
Mississippi is quite muddy, while flying the J3 at altitudes of about a half 
meter (eye height about 2 meters) you can see most floating objects ahead. 
Visibility for submerged objects is better at altitude.  If you look before 
you dive (as I would expect anyone to do, even a pterosaur), you know ahead 
of time which paths to avoid.

Colin McHenry, John Conway, Margot Gerritsen, and I have given several talks 
about the feasibility for some crested pterosaurs to use a process I call 
sailglide skimming to use wind for powering a skimming process with a 
non-rynchopian beak.  For the particular example we looked at, it turned out 
to be feasible in mean annual windfields on the order of  7 knots.  By way 
of comparison and perhaps coincidence, the US Navy has estimated the mean 
annual windfield over the WIS during the appropriate period to be on the 
order of 7 knots.

I think we should keep in mind that there may be more than one way to skin a 
cat and a pterosaur  :-)

JimC