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Re: Lots of things



>ornstn@hookup.net
><<First of all, my understanding is that the presence of hair (or 
>something like hair) in Pterosaurs is not a "fact" but an interpretation 
>of the specimen(s) of Sordes that is not universally shared. It may be 
>likely but not proven.>>
>
>You've got an alternate theory, I'm listening.  There is VERY good 
>evidence that _Sordes_ had hair. 

I really don't know one way or the other, but the following is from an
article posted to the list last September.  I'm not sure I agree with it
(though who am I to say) but just to show I'm not making this up:

FOSSIL FIND MAY REDRAW IMAGE OF PTEROSAURS
By MALCOLM W. BROWNE

Disagreement over the wing structure of extinct flying reptiles has led to a
lacerating scientific debate between paleontologists, the outcome of which could
oblige artists and film makers to begin redrawing the terrible pterosaurs of
fact and fancy......

Paleontologists no longer believe that Sordes pilosus had hair, but its original
name has stuck. The creature had long, membranous wings, in which an elongated
string of bones equivalent to those in the fourth finger of a human hand served
as the supporting structure. The animal probably lived on fish, but it is not
known whether it could dive beneath the surface of the lakes where it hunted.

The latest volley in the debate over pterosaur wings was fired in a report in
current issue of the British journal Nature.... 

The authors of the study, Dr. David M. Unwin and Dr. Natasha N. Bakhurina, a
married couple who are paleontologists at the University of Bristol, England,
said that the fossil evidence suggests pterosaurs were very agile flyers, but
as ungainly as grounded bats when crawling.

The two scientists said that the fossil wing membrane they studied contains
two kinds of fibers once thought to be the remains of hair, but which are now
believed to be stiffeners that evolved in the pterosaur wing to improve its
aerodynamics. Unwin and Bakhurina found long, rigid fibers in the outer sections
of the pterosaur's wing, the part that needs stiffness in flapping flight, and
thin, curly fibers closer to the animal's body, where more flexibility would
have been needed. [END OF EXCERPT]

I admit I have always wondered why, if pterosaurs were really hairy, we
don't see it more clearly in Solnhofen pterosaur fossils - from the same
beds that produced clear feather impressions in Archaeopteryx (and I have
read the section on these finds in Wellnhofer - I admit something is there,
but I'm not at all sure what).  Don't get me wrong - I like the idea of
hairy pterosaurs.  I'm just nervous about being too sure about anything to
do with these weird beasts.

><<be convergent if the two groups developed heterothermy 
>separately,>>
>
>Don't you mean homeothermy?

Yes.  I caught that after the message had gone out.

>tlcomp@iu.net
><<I think they would have ran. Even modern birds will run rather than 
>fly. If you watch them they only fly as a last resort. Why? Because 
>running takes less energy than flying. So I think the "ancient" birds 
>and pterasaurs (especially small ones) would have run.>>
>
>I guess your right.  I'm thinking of all the crows and robins that fly 
>away from oncoming cars without a second thought.  If you chase 
>ducks and sparrows on the ground, they'll normally run away.  I 
>guess it would depend on how much they wanted to get out of the 
>situation.
>
>Peter Buchholz

Well, that's not universally so - but I think it is safe to say that birds
adapted to terrestrial locomotion will use it.  I think it begs the question
to extend this to pterosaurs when the debate itself seems to be over whether
pterosaurs were, in fact, so adapted.
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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