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Re: Quadruped theropods?

Any tripods?

My budgies climb with their legs and their beaks. They would often as soon climb as fly.

Dora Smith
Austin, TX
----- Original Message ----- From: "Neal Romanek" <nromanek@earthlink.net>
To: <twilliams_alpha@hotmail.com>
Cc: "DML" <dinosaur@usc.edu>
Sent: Sunday, May 21, 2006 4:39 PM
Subject: Re: Quadruped theropods?

"What about penguins?" I was my immediate thought, "when they move across ice on their bellies?" But I believe that they too only push themselves forward with their hindlimbs, yes?

On May 21, 2006, at 2:27 PM, Tim Williams wrote:

Graydon wrote:

Birds did eventually find a way to get the forelimb involved in
locomotion again, but no quadrupedal stance.

One minor point, which doesn't really detract from your statement, which is essentially correct given that no modern bird uses quadrupedal locomotion when on land. But the first birds (like _Archaeopteryx_, confuciusornithids, and so forth) probably used all four limbs when climbing trees. Thus, they were arboreal quadrupeds and terrestrial bipeds. The same is probably true for microptorans and _Epidendrosaurus_.

Among modern birds, juvenile hoatzins are arboreal quadrupeds. Certain shearwater species have observed using their wings when climbing up tree trunks.



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