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RE: OLD ORNITHOMIMOSAURS



Timothy Williams wrote:

<But, as I said previously, discovering a single 
coelophysoid-like tooth near a postcranium (even if
that postcranium is coelophysoid) is no 100% guarantee
that the two come from the same animal. Remember those
teratosaurids - carnivore teeth associated with
prosauropod postcrania.>

  Yes, but I'm also reminded of the holotype and
referred material for *Probactrosaurus
mazongshanensis* is a cranium and various postcranial
element (respectively) which are associated, but not
articulated [which is why they aren't paratypes]. But
the morphology is congruent between the two,
suggesting homogeneity of the elements.

<I'd bet the tooth does belong to _Gojirasaurus_, but
only further discoveries will settle the matter for
sure.>

  As much as you could say the likelyhood of two
larger, similar-sized coelophysoids in the same
formation and quarry, but distinct forms, is less
parsimonious and less-likely than to suggest they are
the same form. A tooth of a coelophysoid associated
with the skeleton of a coelophysoid much larger than
any requisite element of *Shuvosaurus* shows that in
any form, there is _one_ coelophysoid. This is the
process, I believe, that Carpenter (1997) used to
suggest homogeneity. I do understand what you're
saying, and would essentially agree; but, if it was
possible the two forms might not be congruent (the
tooth would be either plesiomorphic, or with some
mosaic/chamaeric tendencies) I would agree even more
to not refer the tooth to *Gojirasaurus* until future
discoveries may confirm it. This has been done with
all those tooth-bearing *Megalosaurus* species, the
*Carcharodontosaurus saharicus* case being a prime one
of how the association is wrong [well, for a _lot_ of
reasons]; same for *Dilophosaurus* until the
distinctive and basal form of the elements was uncovered.

=====
Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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