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



Augusto Haro wrote:


> What I said for flapping in an arboreal *Archaeopteryx *is more related to
> equilibrium when the bird is near to fall, independently if it is running
> along branches or not, and not necessarily related to the possible
> equilibrium use of wings in rheas. 


Based on the skeletal anatomy of _Archaeopteryx_, the grasping ability of the 
pes appears to be too weak for running along branches.  


> I think that it is not clear if the deinonychosaurs are much cursorial,
> except for troodontids. Ostrom 76' noted the lenght of the metatarsus
> in *Deinonychus
> *was more comparable with that of *Tyrannosaurus* than with those of
> ornithomimids. In some Recent bird ancestor, a not-so cursorial-wards change
> occurred which implied maintaining an almost horizontal femur. 


I may may be misunderstanding you here, but the subhorizontal femoral 
orientation of birds is associated with the forward shift of the body's center 
of mass.  This forward shift is in turn associated with the development of the 
avian flight apparatus, especially the expanded pectoral musculoskeleton and 
the short tail. 


> I do not know
> if something was advanced against Feduccia's (1993) characterization of the
> very curved pedal unguals of *Archaeopteryx* (and not only those of the
> second digit, or those of the manus) as indicative of arboreal, instead of
> terrestrial habitat. I think the early appearence of a perching foot. 


I don't think we can say with any confidence that _Archaeopteryx_ has a 
"perching foot".  The hallux (first toe) was not even reversed.


> If we
> consider that the metatarsal limbs or the feathered tail are somewhat at
> odds with running in vegetated habitat, 


I don't think we necessarily have to say that that feathered hindlimbs and long 
feathered tail are at odds with running in a vegetated habitat.  Rapid 
cursorial locomotion (=running fast) may not be so important in a dense forest 
because of all the potential obstacles.  This might be irrelevent to 
_Archaeopteryx_, if it did live in a fairly open habitat (plus it didn't have 
long metatarsal feathers).  But for _Microraptor_, which did appear to live in 
a dense habitat, the most important factors might have been the ability to hide 
(such as by seeking refuge in trees), or to be able to dart from side to side 
if pursued.


> there are two suggestions, either it
> lived running in a non-so vegetated habitat, or it lived in a vegetated
> habitat and did not run so much, 


Or both could be true to varying degrees.


Cheers

Tim
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