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lip clarifications

This morning our aquarist came in and plopped down a newspaper with a headline, "Dinosaurs lacked lips according to research," and started barking at me that dinosaurs had no lips and couldn't snarl.  I didn't try to clarify the issue with him, just like I don't try to clarify the "all computers will collapse at the turn of the century" issue for him.  I don't cast pearls before swine.  But you who have ears to hear may glean something useful here. 
As with so many issues in this group, there seems to be unnecessary semantic confusion about something that is not at all semantically unclear in the zoological literature.  Terrestrial vertebrates with teeth have lips.  Period.  They protect the relatively fragile tooth rows, contain salivary secretions, and conceal the often conspicuous inner lining of the mouth.  Both lizards and snakes have well-developed lips, even extremely long-toothed forms such as tree boas.  The upper teeth slip into a pocket between the mandible and the lower lip.  It is painfully obvious to me, having seen a number of dinosaur skulls of various taxa, that all had well-developed lips.
The issue of lip mobility is a completely separate one.  Complex facial muscles and facial expressions are limited today to mammals.  This is not to say that birds and reptiles cannot express themselves visually with their faces.  One can even cite cases where reptiles do seem to use their lips independently in certain contexts.  Snakes of the genus Storeria, for example, sometimes do a "lip curl" when handled.  The function of this behavior is not at all clear.  I see no compelling evidence that any dinosaur could produce facial expressions in any way comparable to what we see in mammals.  (For that matter, many mammals are limited in this regard.)  Nor do I see any compelling reason to believe they couldn't.
I do find it rather absurd that there are so many restorations of theropods with such poorly-developed lips.  Try drawing lizards without lips and you will see what I mean.  They look ridiculous.  I repeat that all terrestrial vertebrates with teeth, amphibians, reptiles, or mammals, have well-developed lips.  It is therefore for those who draw dinosaurs without them to explain why they should be deprived of something that is so widespread and so obviously useful.  It gives a very misleading impression of the appearance of the animal, quite unnecessarily inaccurate in my view given the evidence.

Best regards.