David Marjanovic wrote-
>> 14. manual ungual II much smaller than I
>> Another synapomorphy indicating Ingenia the confuciusornithid sister group, not known in >> any other theropod.
> Apart from Compsognathidae and Mononykinae at least. :-)
Damn. I forgot about these, but I could come up with a quantification that would exclude baryonychines and other basal tetanurines.
Steve Brusatte wrote-
> Well, David, I don't know if this is exactly what you are looking for, but Chiappe (2001)
> defined the clade in the Ostrom Symposium volume. He diagnosed Pygostylia by using
> four synapomorphies: the loss of hyposphene-hypantrum articulations in the thoracic
> vertebrae, the presence of a pygostyle (!), the presence of a retroverted pubis forming an
> angle of 65-45 degrees from the main synsacral axis, and the presence of a wide and
> bulbous medial condyle of the tibiotarsus. He puts both the Confuciusornithidae and the
> Ornithothoraces (as sister groups) into the clade.
His data matrix is a great resource for my analysis btw.
But look at how weak the evidence confuciusornithids are avians is- ;-)
1. no hyposphene-hypantrum articulations
Also found in Mononykus.
As in the oviraptorosaur Nomingia.
3. opisthopubic pelvis
Like segnosaurs, mononykines, dromaeosaurids, Bambiraptor and Sinornithosaurus.
4. wide and bulbous medial condyle of tibiotarsus
As stated in Chiappe et al. (1999)- "The medial condyle is slightly wider than the lateral one, a primitive condition shared by other nonornithurine birds and nonavian theropods."
With these sorts of synapomorphies supporting avian confuciusornithids, it should be easy to defend their oviraptorid position. ;-)