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Re: Yet more on pterosaur quad arm posture



David Marjanović <david.marjanovic@gmx.at> wrote:

>> We agree that animals that are not scansorial do roost in trees.
>
> ...if they can fly there. (WAIR probably counts, too.)
>
> If they climb there instead -- if they do what practically no bird ever does 
> today: start on the ground and climb into the crown --, they're scansorial: 
> natural selection for climbing ability kicks in, and they evolve adaptations 
> to climbing.
>
> Lots of terrestrial or semiaquatic birds roost in trees _because_ they can do 
> so without climbing.

I'm sure this _must_ have been mentioned in the discussion about the
arboreality of basal maniraptorans at some point (especially since
that discussion seems to emerge on the list every two months or so),
but -- what about seriemas? They are terrestrial, maybe even vaguely
deinonychosaurian-like (although Farlow et al. 2011 found the
comparison largely unsubstantiated), their hallux is reduced (like in
tinamous), they roost in trees, but they climb up there:

http://www.oiseaux-birds.com/card-red-legged-seriema.html
https://plus.google.com/104301904461877588678/posts/MEb3NDJLVTK (with
links to photos of seriemas in trees and perched -- somehow -- on
branches)

Perhaps someone can find a better reference; the _Handbook of the
Birds of the World_ may be worth checking out.


*Ref:*

Fowler DW, Freedman EA, Scannella JB, Kambic RE 2011 The predatory
ecology of _Deinonychus_ and the origin of flapping in birds. PLoS ONE
6(12): e28964


-- 
David Černý