Re: pterosaurs & snakes

[Stan Friesen <swf@ElSegundoCA.ATTGIS.COM>]

>From: Robert.J.Meyerson@uwrf.edu (Robert J. Meyerson)
 > 
 > As they got rid of their tail, however, the became far less stable in the
 > air.  It was for this reason, that most pterodactyloids have crests on the
 > head; it serves as a rudder while in flight.

The main evidence *against* this position is the fact that the
size of the crest is sexually dimorphic in Pteranodon.
[Male Pteranodons have larger crests than females of the same speces].

Also, most small pterodactyloids *don't* have a crest (for instance,
Pterodactylus itself has no crest).

Thirdly, some of the crests are very small - especially some of the
nasal crests, as in some of the South American genera.


I know it may begin to sound like a broken record - but I see
more evidence for a display function than an aerodynamic one
for these crests.

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.