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Re: Deinonychus claw use and origin of flapping

Anthony Docimo <keenir@hotmail.com> wrote:

> Theropod backbones and joints lack
> even the most basic requirements for arboreality.
> Refrain: and yet they managed it in time.

Arboreal birds can fly.  Therefore, they typically don't need to climb
up trunks or branches.  Except for juveniles of certain birds (e.g.,
hoatzins, turacos) that have yet to acquire the ability to fly, and so
climb up or within vegetation.  In addition to clawed wings, these
juvenile birds have proportionally large and specialized
branch-grasping feet.  They are arboreal birds, and their pedal
morphology reflects this.

Those birds that climb trunks as adults (e.g., woodpeckers,
treecreepers) have special adaptations in the feet (and often the tail
as well) for trunk-climbing/trunk-clinging behavior.

>> 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...?

Terrestrial bipeds.

> (is the "crocodile-like beast with growing hind legs" theory still given any 
> weight?)

Don't know what you're referring to here.

>> and partly a consequence of their current ecology
>> (negotiating steep and uneven terrain).
>  Which we all know never existed in the Mesozoic.  uh-huh.

Such terrains likely existed in the Mesozoic.  We just don't know if
any theropod (or any dinosaur) was specialized for this terrain.

Oceans also existed in the Mesozoic.  But we don't know of any marine
non-avian dinosaurs.   Just because a particular environment existed
in the Mesozoic, doesn't mean a dinosaurian lineage was there to
exploit it.  Dinosaurs weren't the only game in town.