Re: Microraptor also ate fish

[Tim Williams <tijawi@gmail.com>]

Mickey Mortimer <mickey_mortimer111@msn.com> wrote:


> Saying Microraptor lacks *any* arboreal traits is clearly hyperbole.


Not at all.  As I've said, I'm using the strict definition of
arboreal: rarely spends time on the ground, and forages and shelters
in trees.  Simply entering a tree does not qualify as arboreal.


> The blue whale might lack any arboreal traits.  Microraptor has a lot.  It 
> could clearly climb
> trees if it wanted, was small, had prehensile hands and feet, sharp recurved 
> unguals,
> elongate limbs, a tail that could swivel at its base and was relatively 
> swift, feathers to
> cushion a fall, a distally placed hallux, traits to increase aerial motion 
> (incipient alula,
> asymmetrical feathers) which could only be achieved by using an elevated 
> perch, etc..


None of these attributes are (strictly speaking) arboreal characters.
They are aerodynamic and/or raptorial characters.  Perhaps some of
these could have been scansorial behaviors as well (and therefore
employed for tree-climbing).  Unfortunately, I think the term
"arboreal" is often used far too permissively, such as for behaviors
that are associated with climbing or launching from elevated
vegetation.


BTW, I'm not sure what you mean by _Microraptor_ having a "prehensile"
manus.  I had thought _Microraptor_ was incapable of holding any
object with only one hand.  I also think calling the foot "prehensile"
is bit of a stretch - although at least here (unlike the hand) there
is evidence for digital opposability.


> Now, some of these could work for predation, scansoriality, cursoriality, 
> etc..


Especially if that's what they are adapted for.


> But my point was that we can't just discount these because they could work or 
> did work for
> another purpose.


Yes, I agree.  That's were exaptation comes in.  But this alone does
not mean that such characters were arboreal.


> How many arboreal taxa today also use their tree-climbing features for other 
> purposes?
> Probably a lot.


But these are arboreal taxa.  We haven't even established that
_Microraptor_ was arboreal.


> How many are hindered by features like Microraptor's parasagittal hindlimb 
> motion?
>  Probably a lot.


Name one.  :-)






Cheers

Tim