Re: Krzyzanowskisaurus

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

Whomever David is citing (he never cites his respondents):

<<_Technosaurus_ is deemed "probably ornithischian" because of imbication of
the tooth crowns; increase in the size of the teeth to the posterior center of
tooth row; and because the tooth row is not marginal.>>

  Yes, I am aware the respondent is actually Tim Williams, but for the purposes
of continuity, I am requesting that David cite whom he is replying to, since it
makes following (or not following) a thread he participates in that much
easier.

And David Marjanovic's (david.marjanovic@gmx.at) reply:
 
<Will these 3 characters save it from becoming a sauropodomorph... or example?>

  Imbrication of the dentition (uppers inserting between the lowers) will cause
mesial and distal wear facets, features present in many sauropodomorphans. Not
all "prosauropods" have this condition, however.

  Increase of tooth size caudally from the mesial end of the jaw also occurs to
some degree in "prosauropods" but Heckert is correct in determining that when
crowns at the middle of the jaw are largest, they tend to be in ornithischian
jaws.

  Marginalization of the dentition is also found to SOME degree in
sauropodomorphans, but only distally in the jaw, with an offset lateral margin
of the dentary usually exhibiting a dorsal platform bounded by a lamina that
connects to the coronoid eminence of the dentary or surangular. This will also
result in mediolateral expansion of the dentary diameter, brought about by
expansion of the diameter or because the mandible is rotating so that the
dentition erupt further lingually and more of the dentary is exposed labially.
Ankylosaurs, for example, have rotated the ventral margin of the mandible
laterally, and hadrosaurs have done the reverse, all acheiving a broad lateral
embayment of the dentary.

  Cheers,

Jaime A. Headden

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


        
                
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