Re: Sequential Centrosaurines, Batman!

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

Tim Williams (twilliams_alpha@hotmail.com) wrote:

<BTW, the diagnostic characters of _Brachyceratops_ are thought by some 
authors to be immature centrosaurine characters, and therefore invalid.
Ditto for _Monoclonius_.  Thus, both genera are deemed invalid under this 
interpretation.>

  Yes. However, juveniles _can_ exhibit diagnostic features, even if the
juvenile condition cannot be compared to adults of other species (reducing
their diagnostic utility). The actuality of the features that are present
as unique in combination or existence, or as a dinosaur, ornithischian, or
ceratopsian, etc., makes these features valuable and useful, even if the
naming of the taxon is pushing it. Otherwise, *Chasmosaurus canadensis,*
*Brachyceratops montanus,* and *Monoclonius crassus* are valid in their
uniqueness, but hardly comparable to the adult types and almost completely
adult hypodigms of other ceratopsians. Skulls referred to *Monoclonius*
include the species *M. lowei* and *M. dawsoni,* the former which is
distinct from both *Centrosaurus* and *Styracosaurus,* as well as other
centrosaurines, based on its frill morphology, and indicate they are
possible unique species, even if they may not validate the genus they were
placed it.

=====
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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