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Re: Microraptor hanqingi, new species from China.

> >   But if you're a theropod, and you want to spend a large
> > part of your life sitting on boughs or branches, you need to have a
> > way of holding on.
> This is an active hypothesis, and requires evidence.
> And good luck on that -- it is mechanically incorrect relative to mere 
> sitting or even standing on large, more or less horizontal 
> branches/crotches by even inanimate objects, much less well-clawed 
> theropods that presumably had reasonably competent balancing systems -- 
> "large branch" being defined as relatively rigid, and significantly 
> larger in diameter than the contact point upon which the object or 
> theropod balances.
> Moreover, there is no obvious selective path to a perching foot in the 
> presence of active ground-foraging, the absence of active in-tree 
> foraging, and/or exploitation of small, flexible branches, such as are 
> found in the terminal branch environment.

Who cares about "obvious"? :-) We've discussed the Fowler et al. paper in PLoS 
ONE about the prey-grasping function of the dromaeosaurid foot. That's a good 
starting point for a branch-grasping foot (even though it _isn't_ a 
branch-grasping foot itself).

I think sleeping in trees came next-to-last, followed only by nesting in trees. 
That's because to sleep in a tree, you need a way to hold yourself in there 
_while sleeping_. That can be a specialized foot, a big hole in the tree, or a 
nest; ways of building nests in trees may not be very easy to evolve, and 
finding holes big enough for anything the size of *Archaeopteryx* or 
*Xiaotingia* or *Anchiornis* or any kind of *Microraptor* is difficult. -- I'm 
sure I've overlooked other possibilities. What are they?