Re: tiny theropod on a tree trunk question

[Patrick Norton <ptnorton@suscom-maine.net>]

> One of the minor/major differences in bats and colugos (or colugoes in a
> nod to Dan Quayle) is a preference for one or the other (and remember
> we're talking about tree trunks, not horizontal branches here) with a
> posterior/lateral rotation of the resting carpus in one and not the
> other.

It seems much more likely that the posterior orientation of the carpals in 
birds, bats and pterosaurs is related to selection for increased aerodynamic 
thrust than to any specific orientation when grasping onto vertical 
surfaces.  Posterior/lateral rotation of the carpus is a characteristic of 
all 3 of those groups, and is absent in all groups of tetrapod gliders, such 
as Colugos and the many types of flying squirrel.

PTN