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RE: Deinonychus claw use and origin of flapping






> Date: Fri, 16 Dec 2011 12:02:13 +1100
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Deinonychus claw use and origin of flapping
> 
> K Kripchak <saurierlagen1978@gmail.com> wrote:
> 
> 
> >> So, we end up with arguments that boil down to saying;
> >> "Birds/theropods were unlikely to have become arboreal without
> >> cursorial basal birds/theropods possessing the capabilities, traits,
> >> and behaviours for becoming arboreal. However, the capabilities,
> >> traits, and behaviours for becoming arboreal wouldn't have been
> >> selected for until cursorial basal birds/theropods became arboreal."
> >>
> >> A Catch-22.

> The trouble with this hypothesis is that the overall morphology of
> theropods (their bauplan, if you will) was so poorly adapted for
> arboreality. Even if (and it is still an *if*) certain characters in
> the hands and feet improved trunk-climbing or branch-holding ability,
> these characters must be set against the rest of the skeleton, which
> remained resolutely terrestrial. Theropod backbones and joints lack
> even the most basic requirements for arboreality.
 
Refrain: and yet they managed it in time.
 
 
> This is why comparisons between theropods and mammals are so inapt -
> including goats. The much-vaunted tree-climbing abilities of goats
> are a partly a product of their heritage (placentals began as small
> arboreal mammals)
 
While theropods began as...?
(is the "crocodile-like beast with growing hind legs" theory still given any 
weight?)
 
 
> and partly a consequence of their current ecology
> (negotiating steep and uneven terrain).
 
 Which we all know never existed in the Mesozoic.  uh-huh.
(flowering plants didn't exist - boulders and scree did - if they didn't, 
please point me to the paper saying so)