RE: Two Questions

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

Tim Williams (TiJaWi@agron.iastate.edu) wrote:

<_Lukousaurus_ is a teratosaurid non-dinosaurian rather than a theropod? 
Is this speculation on your part - or has someone published this
re-interpretation?>

  I use the term "teratosaur" loosely in that it tends to define a
poposaurid or a rauisuchian. Not a Teratosauridae, in this sense, which is
poorly defined by fossils anyway. *Lukousaurus* has been considered by
some workers, including Clark and Rauhut (I beleive) as to be
non-dinosaurian, as wass conceived as possibly non-dinosaurian by Kurzanov
et al., 1990. The skull, despite it's small "ceratosaurian" appearance, is
not well-preserved and has been only poorly described. Laying in state in
the IVPP vertebrate paleontology collection (IVPP V), the material needs a
good spanking in the description department.

  However, many reasons to consider this animal to be non-dinosaurian
involve the presence of many non-dinosaurian or basal dinosaur conditions,
including suborbital maxillary tooth row, no ventral extent of the
antorbital fossa, rostral lachrymal protuberances, and an oddly-shaped
orbit with a ventral "notch" and posterior process of the lachrymal that
projects into the orbit and may form a platform for a palpedral
ossification. External nares very dorsally positioned, not rostrally, and
well posterior to the rostral limit of the premaxilla.

  The absence of the caudal portion of the skull makes this taxon's
affinities more difficult to assess in the issue of dino--non-dino.
However, the above features suggest, though do not indicate, a
non-dinosaurian relationship for *Lukousaurus yini* Yang [Young], 1948.
Molnar has communicated to Norman, 1990, that two other similar specimens
are known from the Lower Lufeng (Carnian-Norian, Upper Jurassic) of China.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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