Lightening of the
There is intense selective pressure on flying
vertebrates to develop a light body plan. If a
pterosaur bone is sectioned and compared with that
of a modern bird, one would notice marked
similarities. Pterosaur bones are extremely thin
walled and are not of uniform thickness. The bones
show selective thickening in areas of higher
stress. To further reduce weight the bones are also
hollow and have a system of internal cross bracing.
In the skull there is an additional opening; which
have may served to reduce the weight of the large
Cross section through
© 1991 Christopher
Dinosaurs, Spitfires & Sea Dragons.