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Re: pelicanomimus



From: tholtz@geochange.er.usgs.gov
 > I wrote:
 > >
 > >That's not *quite* correct, but I tend to agree that this is too
 > >many teeth for it to be a proper ornithomimid.
 > >
 > >In that case, it would be in the Coelurosauria (restricted sense)
 > >or in the basal Maniraptora.  ...
 > 
 > But it will be much better in September :-) (see reference 23 in the
 > Pelecanimimus paper)
 > 
 > Anyway, we can do better than that.  Pelecanimimus shares, uniquely with
 > the Ornithomimidae, metacarpals of all the same length and proportions of
 > the phalanges of the hand.  In this respect it is more similar to valid
 > ornithomimids than to Harpymimus. 

Ah, this is important.  Assuming for now that this is a valid
synapomorphy, not a convergence, it forbids placing Pelecanimimus
is a stem group ("Coelurosauria") AND Harpymimus in Ornithomimosauria.
[That would make either the "stem" group or the ornithomimosaurs
polyphyletic, which no biologist will accept].

 >  Also, it shares with all
 > ornithomimosaurians and all troodontids the bulbous parasphenoid capsule
 > (an unusual structure of the braincase).  Therefore, the body of evidence
 > shows that this animal is a member of the troodont-ornithomimosaurian clade
 > (to be named in ref. 23), and additionally is closer to ornithomimids than
 > to troodonts.  Thus, it is an ornithomimosaurian.

This seems right given what you said above.

[And the alternative, *if* the similarities to the ornithimimosaurs
are convergent, and only under that situation, is to place it
in the same group as the Troodontidae - but this seems unlikely].

swf@elsegundoca.ncr.com         sarima@netcom.com

The peace of God be with you.