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Dino teeth -Reply

I'd be very surprised indeed to find out that any dino sprouted anything
like ivory. The term gets used for a wide range of ivory-like materials, but
a purist would correctly tell you that it is strictly defined as the
acellular dentine structure characterizing proboscidean tusks. There is
sufficient variation in growth form and structure to enable just about
anyone with a little training to distinguish fossil from Recent proboscidean
ivory. There is no other structure like it: the complex cone-within-cone
structure is absolutely diagnostic of proboscideans, and no other mammal,
let alone other vertebrate.

However, we all know this is a rotten world for purists, and the term
"ivory" gets used for a wide range of ivory-like or ivory-substitute
materials. It seems that any dense bone or bone-like structure that is
capable of being carved up for scrimshaw or figurines has at one time or
another been referred to as "ivory," including hippo and suid "tusks," any
antlers and horn cores, any compact bone sections (especially mammalian),
narwhal "horns," ratite eggshells, hornbill casques, turtle carapace
fragments, large mollusk shells, and some very dense plant seed coat
structures. This is the context in which elk teeth get referred to as
"ivory." Strictly speaking, they're not. Strictly speaking, too, a dinosaur
can't produce true ivory. 

That does not mean that a dinosaur is incapable of producing dense,
resistant bone or tooth structures, of course, though I'd really rather not
see dino materials put to the scrimshaw test. It just means that true ivory
is a structure limited to a single mammalian group.

Sally Shelton
Collections Officer
National Museum of Natural History
Smithsonian Institution

>>> Randy King <randyk@ims.com> Monday, 4 October 1999 >>>
How much do we know about the composition of dinosaur teeth?  Are
they enameled?  Ivory?  Can we even know for sure?

Someone indicated that he had some ivory elk teeth, which raised the
question.  Does anyone know if elk actually have a couple of ivory 
teeth?  Is it reasonable in dinosaurs?