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Re: Rhamphorhynchus Perching???
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.
Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2 mailto:email@example.com