Re: Pterosaur help and Rahonavis; sickle-claws

["Tim Williams" <tijawi@hotmail.com>]

Silvio Renesto wrote:

> It appeared in the literature that [Megalancosaurus] had a birdlike  
> >semilunate carpal. This was simply due to the hanging  hypothesis of 
> >bird relationships.

An appropriate choice of words.  The evolutionary model which held that 
birds evolved from _Megalancosaurus_ deserves to be "hanging".  Perhaps 
drawn and quartered as well.


David Marjanovic wrote:

> Unlikely IMHO. The function of such a parasagittal climbing device could be
> fulfilled much better by a pamprodactyl foot (all 4 toes point forwards),
> which exists in mouse birds = Coliiformes, while a single enlarged claw on
> II, III or IV which functions as a climbing aid does not exist in any >bird 
> AFAIK.

A pamprodactyl foot seems to be a little drastic, if all you want to do is 
climb up a trunk.  The sickle-claw of dromaeosaurids *might* have been 
co-opted for such a use.  There's certainly more than one way to climb a 
tree.  On that note, you may find this post of particular interest:

http://www.cmnh.org/fun/dinosaur-archive/2001Oct/msg00185.html



Tim

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