Re: Details on Tugulusaurus

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic wrote:

<Alvarezsaurid caudal centra lack pleurocoels. Okay,
but pneumatic depressions seem to be present: [ref] p.
144 ... Reference: Fernando E. Novas: Anatomy of
Patagonykus puertai (Theropoda, Avialae,
Alvarezsauridae), from the Late Cretaceous of
Patagonia, JVP 17(1): 137 -- 166 (March 1997)>

  The pneumatized vertebrae of oviraptorosaurs is
quite extensive, and persists into the distal caudals.
This may be due to the loss of the typical theropoda
distal caudals posterior to the 34/35 vertebrae in
therizinosaurs/oviraptors....

  A pneumatic formen is not a fossa, or lateral
excavation, though ontegeny in some forms may
demonstrate homogeneity, this is as yet unproven. I
can't wait to get my hands of Britt's PhD thesis,
though....

  As for fossae, there are different origins for
fossa, including impressions of air-sacs (pneumatic)
but also tendon inserations, extensions of trochleae,
mere sulci, that have nothing to do with air sacs.
*Achillobator* also persists with caudal
pneumatophores. Sharp-rimmed pneumatophores, shallow
ones with rounded rims, fossae either shallow or deep
as seen in sauropods.... Origins differ, and
terminology has been suggested (Britt, 1997 [in
_Encyclopedia of Dinosaurs_, cf. PhD thesis; cf. also
Makovicky, PhD thesis).

=====
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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