RE: Microraptor also ate fish

[Mickey Mortimer <mickey_mortimer111@msn.com>]

Tim Williams wrote-

> > This all boils down to whether we're actually justified in using the tiny 
> > amount of information
> > we have on extinct animal behavior to say anything significantly likely to 
> > be true. Without
> > some broader study on the kinds and frequencies of arboreal adaptations 
> > today, and the
> > influence of novel variables such as Microraptor's clawed wings and solid 
> > mobile tail make,
> > can we even make a useful statement about its arboreality?
>
> I think we can. For _Microraptor_, the lack of *any* arboreal traits
> is telling. Motion at the joints is very limited or highly
> proscribed, as it is in all theropods. (Although there is evidence of
> increased range of motion at the acetabulum, this is found in larger
> and incontrovertibly terrestrial dromaeosaurs too.) The manus and pes
> of _Microraptor_ lack any apparent adaptations for branch-grasping -
> apart from those that possibly have a raptorial function (as well?).

Saying Microraptor lacks *any* arboreal traits is clearly hyperbole.  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..  Now, some of these could 
work for predation, scansoriality, cursoriality, etc..  But my point was that 
we can't just discount these because they could work or did work for another 
purpose.  How many arboreal taxa today also use their tree-climbing features 
for other purposes?  Probably a lot.  How many are hindered by features like 
Microraptor's parasagittal hindlimb motion?  Probably a lot.  But without some 
study of these frequencies in living taxa, how are we to say anything about 
extinct taxa?

Mickey Mortimer