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Re: Making Lip of It
----- Original Message -----
> From: Augusto Haro <email@example.com>
> Besides, I think that another (rather weak, I admit) argument to say
> lizard-like lips were not present in non-avian dinosaurs (accepting
> their function is to keep teeth wet) may be that carnivorous dinosaurs
> and some archosauriforms have teeth generally longer than most
> carnivorous squamates. Thus, the lip should be generaly longer than in
> a lizard. For the dinosaur to bite something, and the long teeth to
> enter deeply into the flesh, the lip should be raised. This required
> to raise a bigger lip, which would require more lip musculature.
> Perhaps mammals can accomplish raising bigger lips which commonly
> protect longer canines because the larger amount of voluntary muscle
> present. Lizard teeth are commonly so short (or, when long as in
> snakes and monitors, so caudally pointing) that perhaps the lip has
> not to be raised too much more than passively for the teeth to mostly
> penetrate prey.
I'm not sure how necessary lip musculature would be for this. Unless the lips
were overhanging to such a degree that they could fold inward on the teeth, I'd
suspect that passive suspension on the jaw would be all that's needed to allow
the teeth to pierce through prey (whose own bodies should provide enough
resistance to allow the teeth to move beyond the lips. A similar situation like
this is believed to exist in Komodo dragons, except that it involves the gums
instead of the lips. Mammal lip musculature is certainly impressive, but all
the cases of lip raising that I have seen (lions, baboons, wolves) are always
done as a signal to congeners (typically telling them to back off). The
infamous Indian tiger attack on a man riding an elephant seems to show that
regular attacks don't really require pulling the lips out of the way.
(blurry, but effective).
with a lion).