Re: Silesaurus and Trialestes

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

Tim Williams (twilliams_alpha@hotmail.com) wrote:

<Something that occurred to me recently... it would be interesting to
compare the recently described _Silesaurus opolensis_ with _Trialestes
romeri_, which was recently touted as a possible early dinosaur (Clark,
Sues and Berman, 2000).  In both taxa, the forearm is very long, and
exceeds the length of the humerus.  Both _Silesaurus_ and _Trialestes_
also come from around the same age (late Carnian) (Dzik, 2003), not that
that means very much by itself.  _Silesaurus_ has a closed acetabulum,
whereas that of _Trialestes_ is perforate; but this character is very
labile in early Dinosauria/Dinosauriformes (e.g., _Guaibasaurus_ and
_Saturnalia_ both have a closed acetabulum).>

Micket Mortimer also thought of this a while back ...
http://www.cmnh.org/dinoarch/2001Feb/msg00439.html.

  The description of the carpus includes that it had elongated radiale and
ulnare, features unknown in dinosaurs, but possible in basal
dinosauromorphans given that animals ancestral to Archosauria have it, in
addition to crocodylomorphans. Based on what Reig (1963) did during his
description of the material and what is noted by Clark et al. (2000), it
is likely that *Trialestes* should be restricted to the skull, and that
the distinct postcrania possibly be given another name, as some of the
material is indicatively crocodylomorphan, and the other "dinosaurian."

  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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