Re: Rhamphorhynchus Perching???

[Ronald Orenstein <ornstn@home.com>]

At 07:18 AM 08/08/00 -0400, Larry Febo wrote:
> I`m not sure pterosaurs could have perched on a branch using their feet
> alone.  They didn`t have the locking tendon mechanism, and no reversed
> hallux to aid the grasp. I would think they would have climbed about in
> cycad branches with both feet and hands. They may have been bipedal on the
> ground,........but, I`ve never heard Dave Unwin mention this (quite the
> opposite in fact!).

It is, I am afraid, a misconception that a reversed opposable hallux and 
locking tendon mechanism are necessary for perching.  The locking mechanism 
in particular is a feature of the Passeriformes or "perching birds", and 
non-passerines like parrots and hawks have strongly opposable grasping 
toes, but there are a good many birds that perch in trees quite 
successfully without relying on either feature.  Examples are whistling (or 
tree) ducks, cormorants, and herons.  The lack of these features in 
pterosaurs is therefore not conclusive.


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Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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