Re: Rex Jaws

[Betty Cunningham <bettyc@flyinggoat.com>]

Birds have no lips-they have beaks (a condition shared by a great many
dinosaurs, thank you)
Do birds have the muscle attatchments for lips (left over from a lipped
past) or not?

Bird lower jaws are very slim (as a weight reduction probably).  Would a
bird have room in it's jaws to have multiple rows of teeth, much less a
single row?  What kind of tooth row-and-replacement did Archie have?

Do birds have gums and gum tissue since they have no teeth or lips?  (I
know what hawks have under the tongue at least)

-Betty

Tracy Ford wrote:
> As stated before, mammals have muscles to 'smack' their lips and 'lizards,
> snakes, the tuatara doesn't.

>  I haven't seen them when I've looked at croc
> skulls, perhaps Chris Brochu has a comment?  While on the subject, what
> about the exuberant gum tissue that is seen in most reptiles?  Teeth are
> usually felt more than seen, even long ones.  I suspect the pink sticky
> covering has something to do with continuously replacing teeth, but I
> haven't been able to find anything about it in most basic reptile
> references.  Any help from the experts here?   When I have looked at large
> theropod skulls, the polished and worn area on the teeth seems to begin at
> a distance from the bone, suggesting that gums were probably there.
> 
> Not really. It also suggest a few things, one, the tooth in the skull has
> been displaced, or it's beginning to be pushed out by the incoming tooth.
> Stan has it's teeth nearly falling out (some disagree, but Neil Larson
> agrees) but the roots are still in the maxilla. What you do see is the
> enamel of the tooth, then the root, which is huge in some cases.
> 
> IMHO theropods had crocodilian jaws, no lips but ornithischians had, well, I
> need to do more research and there are a few papers coming out that will
> comment on this by others which will have a great impact on this subject
> (hopefully in the near future).
> 
> Tracy

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