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Re: Thou Shalt Not Climb!

On 6/29/07, mariusromanus@aol.com <mariusromanus@aol.com> wrote:

Were basal birds up in the trees before they had the modern traits we now use to define a bird as arboreal??? If yes, what were the traits that allowed them to be there? If not, then why did selection favor characteristics for an arboreal lifestyle?

Aren't most terrestrial vertebrates (below a certain size) capable of getting into trees? There's even at least one non-tetrapod capable of it: mudskippers.

I would imagine that archosaurs (and amniotes and crown-tetrapods)
have "ability to get into a tree" as the ancestral condition, only
absent in some lineages due to derived conditions (large size,
fossorial or aquatic adaptations, armor, etc.).

Seeing as few pan-avian subclades have derived conditions like these
(except for "large size"), and seeing as they all began life at a
relatively small size, I would think most were capable of getting into
trees. The preconditions for arboreality are pretty old, I think.
Mike Keesey