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Don Ohmes <email@example.com> wrote:
> It follows that a "jumping-out-of-trees" evolution-of-flight scenario is not
> falsified by a perceived lack of "arboreal adaptations", given vertical
> climbing competence.
I'm inclined to agree with you here. If vertical climbing competence
can be demonstrated for basal paravians, we have a ball game.
> So a conclusion that a wing-clawed vertical climber is/is not "arboreal" is
> interesting ecologically, but irrelevant in terms of "tree's down" vs
Agreed. There is abundant evidence than no basal paravian was adept
in trees. Dececchi & Larsson (2011) presented a strong case against
basal paravians being arboreal. But IMHO the absence of arboreality
does not necessarily refute a "trees-down" origin of avian flight.
> Which might imply that the wing-clawed
> Archie/Archie-ancestors/Archie-siblings/ilks and sundry et als could ascend
> a tree stepwise more competently than the reverse process, which is
> descending stepwise -- as is typical in vertical climbers.
Again, agreed. I'm convinced that basal paravians could not climb
*down* trees (e.g., see Dececchi & Larsson, 2011). But was it the
need to get out of trees that provided the initial selection for
> Adopting as a working hypothesis that it did in reality both climb and sleep
> in trees, what evolutionary mechanism would change the pes beyond that seen
> in the fossil?
I suspect that sleeping in trees would favor the appearance of
branch-grasping/perching adaptations, in either the hands or the feet.
The absence of said adaptations is why I'm so cold on the idea of
roosting behavior in basal paravians.