Snarling theropods

["Michael Lovejoy" <michael@palaeoproductions.fsnet.co.uk>]

When I bought a Playstation a few years back, there was a demo disc with it
which contained, amongst other things, a virtual T.rex. You could move it's
head, make it roar etc. One of the things it could do is lift it's lips in a
snarling gesture.
So, what's the current feeling on snarly lips on theropods? While it's
unlikely that theropods had lizard-type lips (no glands?) what about the
possibility of mammal-type movable lips? After all, mammal-like cheeks are
accepted by most for some dinos, and many extant birds can raise and lower
feather crests, showing that skin muscles on the head is not unusual in
archosaurs. Also, snarly lips seem to be used in mammals for display, and
visual display was clearly important to theropods, as evidenced by the
plethora of crests and horns on many species. IIRC, Greg Paul illustrated a
Dilophosaurus raising it's lips in PDW.

So, raised, snarling lips on a theropod ? Let's have some opinions on this,
please!

Regards,
Michael Lovejoy
PalaeoProductions
http://www.palaeoproductions.fsnet.co.uk
Michael@palaeoproductions.fsnet.co.uk