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RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)



Eike (koreke77@yahoo.de) wrote:


> True, if I would argue for arboreality of _Microraptor_. But what I'd argue 
> for here is that it undeniably 
> differs from most relatives in the same size class in an adaptation (hindlimb 
> wings) that is detrimental to 
> the way smnall theropods escaped predation - running away. The leg feathers 
> were unlikely to be 
> helpful as long as the toes touched the ground, and probably were even quite 
> detrimental in any sort of 
> vegetated habitat. Especially as they were not leg but midfoot feathers.


I agree that long metatarsal feathers would not have been at all helpful when 
running.  However, I think the idea that these feathers were a hindrance has 
been overstated.  Firstly, the digitigrade foot would have helped keep the 
metatarsal feathers from dragging along the ground.  Secondly, would the 
hindlimb feathers be any more detrimental to running through close vegetation 
than the long, stiff, feathered tail?  


> So there must have been *something*, either in its ecosystem or in its 
> behavior, that allowed these 
> features to evolve in the first place - lack of predators, de-emphasis of 
> cursoriality, whatever.


Yes, I agree with you here.


> As with Archie, _Microraptor_ was not a percher. 


And here.


> And I think that it is hard to challenge the assumption that Archie, 
> _Microraptor_, as well as all 
> other "protobirds" were terrestrial bipeds first and foremost. But were they 
> anything else, and if yes 
> what, and to what extent?


Yes, I think this is the most important question of all.  It takes a large dose 
of 'special pleading' to reconstruct _Microraptor_ and _Archaeopterx_ as 
specialized arboreal animals with highly evolved climbing and perching 
abilities.  Most tellingly, it took a long time for birds to shake off their 
ancestral cursorial/terrestrial body plan.



Cheers

Tim
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