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Re: Gliders to Fliers? (Was Re: Ruben Strikes Back)
In a message dated 9/26/99 1:36:14 AM EST, mbonnan@hotmail.com writes:
<< This is where I would say we have to be careful. As I mentioned, the
cylindrical femoral head and hinge-ankle of theropods would not lead me to
say "almost certainly" theropods are descendants of arboreal animals. What
of bipedal ornithischians? All of these forms are bipedal because of
arboreality as well? >>
As a matter of fact, I would say they are. The correlation between bipedality
and ancestral arboreality is quite strong. This is not to say that an
arboreal lifestyle invariably leads to bipedal descendants, but rather that
we should certainly look for evidence of an arboreal lifestyle in the
ancestors of bipedal animals, and that bipedality by itself may be evidence
of a prior climbing arboreal lifestyle. I for one don't think bipedality
"just happened" in the lineage that later evolved into dinosaurs, because
bipedality is not a particularly safe mode of locomotion. Break a leg, and
where are you, if you're bipedal?