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Microraptor hanqingi, new species from China.

> Again, I actually like the idea - since you're the one who pointed it out here, I was hoping you had some suggestions for what we'd predict if tree-roosting was indeed important to paravians.

The idea was never advanced by me as a testable lifestyle for any particular fossil specimen -- that would be a "misunderstanding" -- but it falsifies the idea that an animal evolving flight in tree-down gliding-first mode will by evolutionary logic show "arboreal adaptations" in its skeleton -- beyond the basic capacity to climb a tree...

I suppose predictions made by tree-roosting might include 1) limited upstroke early on (that is, even after the appearance of a sophisticated gliding wing), 2) that the perching foot would appear subsequent to powered flight (full upstroke), not before -- and 3) the capability of climbing vertically.

One note -- controlled climbing up is easier than climbing down -- and in the hoatzin type wing-claw model, climbing down would appear to be problematic, which makes parachuting/gliding useful.

In any case, I am unsure that these are unique predictions, and would be useful in "proving" tree roosting -- although I suppose in sum they might be a start.

Given that the possibility of a tree-roosting lifestyle falsifies certain assertions about the relevance of "arboreal adaptions" to bird flight evolution, I think any statements that the "discussion" was not fruitful are wrong.

> If your assertion is, instead, that we'd see no difference in the fossil record between a case a fully "terrestrial" origin and a "terrestrial + tree roosting" origin [...]

Yes, that is my assertion, but relative only to pes morphology in small cursorial, feathered, vertical-climbing, etc, etc...

I would think a strict ground-up scenario might predict a full wingstroke early on, even when wings are rudimentary -- but suppose that to be debatable.

Foraging in a tree would necessarily alter the feet, by evolutionary logic -- but just sitting or sleeping in a tree will not necessarily do so, especially given a ground-foraging lifestyle and the attendant conserving of cursorial morpho-type.

> then I'm not sure what is being argued.

Good question.

You could comb through the various threads and find other people to ask -- apparently no paravians would or could roost in trees, sauropods and tall theropods would pluck them off branches like so many peaches, any "rooster" would fall off and die when sleep came (yet could pounce on prey from the same branch with great success), and my personal fave, sickle-type claws would shear through any branches they gripped like pruning shears.

Interesting stuff...