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

[Tim Williams <twilliams_alpha@hotmail.com>]

Scott Selberg wrote:


> I appreciate that the thread was about archeopteryx climbing ability, but my 
> main objecteve was to explain the differences 
> in morphology between Archeopteryx and Microraptor and why one had hind wings 
> and a well developed sickle claw and 
> one did not--that it was primarily a difference in habitat--that Microraptor 
> was steering through branches and landing on 
> tree trunks, while Archie was simply crash landing on top of small trees.


Yes, but all these things are intimately connected.  Your proposed scenarios 
for _Archaeopteryx_ and _Microraptor_ are predicated on the assumption that 
both theropods were to a large degree 'arboreal'.  So we need to examine the 
'arboreal' abilities of these theropods (scansoriality, perching, etc) before 
looking at the biomechanics of flying and landing in (or on) trees.


I don't deny that there are some very poor climbers among modern gliders (like 
the Japanese flying squirrel); and some modern arboreal animals are exceedingly 
ungainly in the trees (like the tree kangaroos, which evolved from terrestrial 
ancestors).  But even these guys have a skeletal anatomy far better adapted for 
arboreality than any non-avian theropod or basal bird.


> About Archies climbing ability--it's my understanding that Confuciusornis is 
> considered a climber.What adaptions for climbing
> (not including reversed hallux),does it have that Archeapteryx lacks?


None at all, AFAIK.  So I would argue that _Confuciusornis_ was no better at 
climbing than _Archaeopteryx_ was.  _Changchengornis_ shows a slightly better 
grasping pes; but the idea that any confuciusornithid was particularly well 
adapted to climbing is very poorly supported anatomically.




Cheers

Tim


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