Re: Gliders to Fliers? (Was Re: Ruben Strikes Back)

[Dinogeorge@aol.com]

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?