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Re: Another tooth question



Thomas Hammann wrote:

<Last weekend I've read an older article in National
Geographic from Sereno entitled "Africa's Dinosaur
Castaways" (June 1996; pp 106-119). There are some 
great pictures of the famous
Carcharodontosaurus-remains, but one of it seemed to
be a little mysterious to me. On the photograph at the
bottom on page 108 you can see a big single tooth
which is described as followed: "Once it has been
cleaned, a five-inch tooth reveals a series of grooves
- their purpose unknown."

You can see the grooves very well on the picture. So
I'm asking myself if the other teeth of the discovered
piece of skull (which was shown in many newspapers in
May 1996) also have got such grooves. If yes, this
would possibly mean that all the (mostly smaller)
teeth from Morocco I know from fossil-shows could
belong to an other species. I don't think so, but if
all teeth of Sereno's specimen have such grooves I'm
not so sure about the identification of
Carcharodontosaurus-teeth as I was before.>

  All the maxillary teeth of Stromer's original skull
and Sereno's new one [more complete] have the
characteristic "blood-grooves" that extend as pleats
onto the side surfaces of the tooth. The skull
(SGM-Din 1) shows nearly all maxillary teeth intact,
save the posterior 4, and there are 14 preserved
sockets. Each tooth possesses the same characteristic
grooves, as do a variety of teeth collected around the
skull fragments. (Sereno et al., 1996.)

  Newly erupted or smaller teeth, as in Stromer's jaws
and a variety of isolate teeth I've had the chance to
see are distinctly symmetrically triangular, giving
the animal its name, the longer (or older) the teeth
or animal, the more rear-curved the teeth become. But
all possess the same groove pattern.

  It would seem to me, then, that the more symmetrical
the teeth, the younger the animal that produced them,
but we'd need more specimens for that.

  Sereno, P.C.; Duthier, D.B.; Iarochene, D.M.;
Larsson, H.C.E.; Lyon, G.H.; Magwene, P.M.; Sidor,
C.A.; Varrichio, D.J.; and Wilson, J.A. 1996.
Predatory dinosaurs from the Sahara and Late
Cretaceous faunal differentiation. _Science_ 272:
986-991.

Stromer, E. 1931. Wirbeltier-Reste der Baharioje-Stufe
(untertes Cenoman). 10. Ein Skelett-Rest von
Carcharodontosaurus nov. gen. _Abhandlungen Bayer
Akademie Wissenschaften Mathematische-naturwissen_ 9:
1-23. [in German]
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