On 10/12/2011 1:28 AM, Tim Williams wrote:
I've wondered about this. It is likely that bipedality preceded predatory behavior in dinosaur evolution.
This is a new idea to me. How come?
The study of Martinez et al. (2011) further indicates that the ancestral body plan for dinosaurs included a proportionately long forelimb (~45% hindlimb length) and a sharp-clawed manus capable of hyperextension. Theropods show a shift to a more raptorial/grasping manus (elongate penultimate phalanges of manus, etc). Nevertheless, it appears to me that once dinosaurs became bipedal it was a case of: "So, what do we do now with these appendages?"
A consequence of the balance-beam type body -- erect bipeds are not constrained relative to arm length, but have no use for tails.
Thankfully...