RE: Terrestriality is a bias

["Norton, Patrick" <Patrick.Norton@state.me.us>]

Betty wrote:

>If it's using this odd finger morphology to feed >exclusively< in trees   
couldn't that be a legitimate sign of arborality (living in trees)?<

The fact that the two extant taxa cited as having this feeding adaptation   
are arboreal animals is interesting, but that doesn't necessarily mean   
that the character occurs "exclusively" among tree dwellers.  And even if   
it does, it's clear that it's obviously not an essential arboreal   
character, since other arboreal animals with an equally long evolutionary   
history---even the other lemurs--don't possess that character and do   
perfectly well living in the trees.

>Or are we really meaning 'brachiality' (climbing ability) when throwing   
this 'arborality' term around?<

Since we don't know the osteological correlates for arborealty, that term   
seems to be relatively meaningless in a paleontological context.  We   
could probably come to some agreement on this list as to what constitutes   
an arboreal or scansorial lifestyle, but it does not appear that anyone   
is yet able to infer that lifestyle from a fossil skeleton of extinct   
taxa.

PTN