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Re: Jinfengopteryx elegans the troodontid



I wrote-

> I'll save my final judgement until I get the data matrix of Ji et al.
(since
> they include Sinovenator, and Jinfengopteryx does not clade with it), but
it
> seems we have the most complete troodontid known, and the only one with
> preserved feathers.  The matrix seems to be a modified version of Norell
and
> Clarke's (2001), with some added non-birds.  Perhaps it suffers from the
> same problems that place oviraptorosaurs in Ornithurae in Lu et al.
(2002),
> i.e. analyzing non-birds in a bird matrix.

Now that I have the matrix, my opinion remains unchanged.  You can read
details here-
http://students.washington.edu/eoraptor/Troodontidae.htm#Jinfengopteryxelega
ns
And no, Jinfengopteryx is not synonymous with Sinovenator or Mei.
Sinovenator lacks the heterodonty in tooth size and density seen in
Jinfengopteryx and most troodontids (Senter et al., 2004), has more teeth,
and lacks posteriorly bifurcated chevrons.  Mei has a much larger naris
that's posteriorly displaced, more teeth, a depressed nasal, less cervical
vertebrae, shorter cervical ribs, large hypapophyses, more elongate mid
caudals, lacks posteriorly bifurcated chevrons, has a less distally expanded
scapula, and other differences.  Sinovenator is much more similar, and
Jinfengopteryx actually has one of its supposed apomorphies (straight and
vertical anterior margin of antorbital fenestra), the other three being
unknown in Jinfengopteryx.  Similarly, the apomorphies of Jinfengopteryx
I've identified are unknown in Sinovenator.

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html