Re: Gliders to Fliers?

[Raymond Ancog <rayancog@pacific.net.ph>]

Matthew Bonnan wrote:

>My question for you, or anyone else on the list, is this: all the gliding 
>animals I am familiar with incorporate both their forelimbs AND hindlimbs in 
>the act of gliding.  Flying squirrels use a patagium which spans from fore 
>to hindfeet.  Gliding lizards have a sheet of skin/scales that stretches 
>between the fore and hindlimbs.

>If birds are descendants of small arboreal archosaurs (dinosaur, 
>non-dinosaur) which were gliders, how do you think the decoupling of both 
>the forelimbs and hindlimbs took place?  Am I missing something: are there 
>gliders which do not use both limbs with a sheet in between?

Well, we have the modern-day flying lizards (_Draco_) of SE Asia, with
patagia stretched on elonaged ribs, w/o using the limbs; the superficially
similar weigeltisaurs (though a paper says the supporting bines weren't
ribs attached to the vertebrae) of the Late Permian; the kuehneosaurs of
the Late Triassic; and modern-day gliding geckos (or more appropriately,
parachuting geckos), with modest, boneless skin flaps at their flanks.


Raymond Thaddeus C. Ancog
Mines and Geosciences Bureau
Philippines