Re: perching in pterosaurs

[David Peters <davidpeters@att.net>]

DP: 
> Quad launch from a tree was, no doubt, customary among
> pterosaurs clinging to tree trunks like lemurs do.

TW: Except that the postcranial morphology of pterosaurs is nothing like that 
of lemurs.

Take off the wing finger of any taxon from Longisquama to Sordes and you'll 
have an analog in basal primates from lemurs to tarsiers. Especially so among 
the short-necked pterosaurs. What are the differences in your opinion? Let's 
talk specifically. 

> If perching on branches bipedally, a simple drop and fly seems
> appropriate.

TW: If it was a percher, then yes.  But perching may have been the exception 
rather than the rule for pterosaurs (if it happened at all).  I know it's been 
argued that little _Nemicolopterus_ was a percher; but although it's likely to 
have been a tree-dweller, _Nemicolopterus_'s arboreal characters suggest 
suspensory behavior rather than bipedal perching.  (To me, anyway.)

http://dml.cmnh.org/2008Feb/msg00105.html

I appreciate your thoughts, Tim. Have you considered the hypothesis that an 
elongated digit V acted as a universal wrench to enable perching? It worked 
like a reversed hallux, except opposite in every way. It was lateral, not 
medial. It opposed the branch surface by extension, not flexion. It contacted 
the branch surface with its inverted dorsal surface caused by hyperflexion of 
p5.2, rather than its ventral surface as in birds. And no claw was involved. 



David Peters
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