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RE: Yet more on pterosaur quad arm posture



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> Date: Fri, 12 Jul 2013 09:48:06 +1000
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Yet more on pterosaur quad arm posture
>
> Scott Hartman <skeletaldrawing@gmail.com> wrote:

>
>> Regardless, the act of roosting is not scansorial activity, and would
>> not result in any sort of flying-squirrel selective pressures -
>> instead it would seem that the vast majority of selective pressure
>> would still occur on the ground, where the organisms have to eat,
>> mate, and flee danger for most of their lives.
>
>
> Exactly. The corollary of this is that if a theropod spent most of
> its time in trees, that's where the selection pressures would be
> applied. I can accept that _Microraptor_ and kin were capable of
> venturing up into vegetation, although spending most of their time on
> the ground (including when nesting or sleeping). But if these
> theropods spent most or all of their time in trees, they would be
> under strong selection to acquire appropriate "arboreal" adaptations,
> such as for grasping branches. However, these traits are not apparent
> in basal avialans or non-avialan theropods (although _Bambiraptor_ has
> been regarded as having a somewhat opposable manus). But no way were
> any of these non-avialan theropods adapted for living in trees.

Is there any difference between climbing a {flowering plant} tree, vs a pine 
tree, a cycad, a boulder/kjope, a sauropod, or anything else which would have 
been an off-the-ground home/feeding platform for basal avialans or non-avialans?
(hard to say "they didn't climb like modern tree-climbers" suffices, when 
modern trees weren't the only things around then; yes?)