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Re: Fwd: Aw: RE: Arboreal Theropods: The prize at the bottom of the cracker jack box
Tim Williams wrote:
>Don Ohmes wrote:
>> Analog, schmanalog. The mechanics of standing on a horizontal rigid branch
>> are the same as standing on
>> flat ground -- whatever your neutral pose is
>> It is irrelevant, ecologically...
>It is? You're a biped (I assume). Give it a try. Is standing on a
>branch really as easy as standing on flat ground? :-)
A horizontal branch that 2x the length of my foot in diameter presents little
challenge, in my experience. And a branch 2x the diameter of the impressively
clawed M zhaoianus foot is quite a small branch...
>Birds that roost in trees *typically* have a grasping pes, even if it
>is not optimized for perching; the hallux is reversed, and able to
>oppose the other three toes in anisodactyl grasping. I know not all
>roosting birds do this. But to argue that this feature was not
>required for roosting in non-bird maniraptorans strikes me as special
The above is special pleading of the most brazen sort. It boils down to a
The turkey is presumably descended from an ancestor with the iconic "perching
pes", and roosts nightly -- yet the hallux has *become* vestigial relative to
grasping function -- as one would expect, given it's foraging habits.
Reality and evolutionary logic stand contra the contention that sheltering in
trees inevitably alters the foot -- and rebuts the contention that a trees-down
path to flight is necessarily associated with "arboreal adaptations".