Re: Nemegtian tyrannosaurs

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

George Olshevsky (dinogeorge@aol.com) wrote:

<You never know. Today's pet theory could well become tomorrow's
nonsense.>

  Not to be crude, but does this include one's own pet theories, such as
George's BCF? Carr's, Holtz', and Currie's theories are based on the
multitude of data; as shown through previous arguments, George does not
consider much of this data valid without explaining why, just to assume
one or two features of choice are automatically better. George has stated
his data is more right by invoking parsimony, but by the basic
understanding of parsimony, the _a priori_ rejection of the multitude of
data to favor one or two features for an alternate topology is not, in
fact, parsimonious. George has not shown why *T. efremovi*,
*Maleevosaurus*, and *G. lancinator* are not juveniles of *Tarbosaurus
bataar*, which is a questionable approach to regarding them as valid taxa
versus the adult forms.

  That other purported juveniles of *T. rex* have been regarded as valid
taxa otherwise is not a valid indicator of distinguishing Nemegt and Hell
Creek faunas to indicate how the relative plethora of "adults" in rex
known show how *Tarbosaurus* is so "rare". This also ignores the
taphonomic variability and paleoenvironmental conditions between the two,
one being a higher, drier and probably less wooded area than the other.
The Nemegt is more like the Judith River in structure and should be better
compared to that than to the Hell Creek. Tyrannosaurus and Aublysodon may
merely represent immigrants from Asia. And contrary to an earlier
statement, referral of *Aublysodon* to *T. rex* was based on the
postcranial and cranial material, rather than just the type. This may
merely allow the type to be pulled with the rest, but one should abhor
referral of tooth types beyond a general group rather than any species.

  Cheers,

=====
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.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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