RE: Sereno's (2005) new definitions

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

Michael Mortimer (mickey_mortimer111@msn.com) wrote:

<You can run the Troodon formosus holotype premaxillary tooth in a matrix as an
OTU.>

  This is assuming it's a premaxillary tooth crown. When Currie originally
suggested this idea, he was VERY circumspect about it and merely suggested if
he was to offer an ID on position, it seemed likely to be PMX in nature.
Rather, NO premaxillary or maxillary tooth crowns are known _in situ_ in any
North American troodontid crowns so far described, though several dentaries
have _in situ_ crowns with similar shapes. Premaxillary and anterior maxillary
teeth are also largely corresponding in many taxa, and a survey of crowns in
troodontids (pers. obs.) suggests that the crown, if "premaxillary", may also
likely be "mesial maxillary", but this morphology is seen in mesial dentary
crowns as well. In addition, dentary crowns have larger denticles for crown
size when present than uper jaw teeth (again, when present) in jaws with _in
situ_ crowns. This ambiguity makes assigning the ANSP crown to position
ambiguous.

  Cheers,

Jaime A. Headden

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

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