Re: the reason I asked about maniraptor limbs

[Dann Pigdon <dannj@alphalink.com.au>]

Tim Williams writes: 

> I thought this was true for all maniraptorans.  The palms face inwards, 
> but the hindlimbs are held vertically and restricted to parasagittal 
> movement.  Whether this combination is suitable for trunk-climbing is a 
> totally different question.

This is pretty much how cats scale a vertical trunk. Foreclaws grip the 
sides of the trunk, while hindclaws mostly face forward to provide traction. 
Other (more arborial) species that can rotate their ankles to grip 
side-to-side are capable of decending a trunk head-first, since their fore 
and hind feet can swap roles. Cats can't do this, and have to back down a 
vertical trunk slowly (or wait for the fire department). 

There's a simple way to demonstrate this up close. Put a cranky cat on its 
back and try to tickle its belly. Your hand will be gripped mercilessly from 
side-to-side by the manual claws (causing puncture wounds), while the pedal 
claws will pump back and forth in a more saggital plane (causing 
lacerations). Try it and see... 

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Dann Pigdon
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://heretichides.soffiles.com
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