Re: Terrestriality is a bias

[Ronald Orenstein <ornstn@home.com>]

> All the references I've checked indicate that the Aye Aye's elongated digit
> is an adaptation for feeding (reaching into holes in trees to extract
> larvae) not for arborealty. It is unique among all arboreal lemurs in having
> that modification.  If that's the case, how does your analogy support
> arborealty in this new little dinosaur?

Just to note that it is not unique in mammals, though - the Striped Possum 
Dactylopsila trivirgata of northern Australia has a quite similar 
modification, an elongate fourth finger used to extract wood-boring beetle 
larvae.  It, too, is arboreal (though the only one I ever saw was a roadkill!).

I would be inclined to think that a similar modiication in a fossil might 
well be evidence for at least a partially arboreal habit, but of course it 
might also be useful for extracting grubs from fallen logs or termites from 
terrestrial mounds (if these existed at the time).  A similar adaptation, 
in a way, might be the habit of chimpanzees, which use a thin twig to 
extract termites from mounds on the ground.

--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com