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Re: polyphyletic Alvarezsauria assemblage



The hindlimbs are quite different in Alvarezsaurus and mononykiforms (particularly the latter being hyperarctomet, as in Avimimus). Mononykiforms and Avimimus also share a fused carpometacarpus.
The absence of the m. cupped. fossa on Mickey's list also occurs in oviraptorosaurs and segnosaurians (the latter which I believe are probable Alvarezsaurus relatives).
And I believe Jaime mentioned that Alvarezsaurus had a wide supracetabular crest (which was interpreted as a reversal of sorts). Perhaps it is just primitive.
Alvarezsaurus lacks any large hypapophyses on the anterior dorsals. And it lacks carotid processes in intermediate cervicals. Present in mononykiforms.
The caudals also seem to differ, other than the fact that that they share the procoelous caudals (and sacrals). I should also mention that Gargantuavis had procoelous sacrals.
The anterior trochantor splits from the greater trochanter closer to femoral head in mononykiforms (as in other Class Aves sensu lato).
That's all I have time for tonight, but I think this is a good start. I really think Mickey is going to find a few surprises along these lines in his updated analysis.
---- Cheers, Ken
P.S. By the way, now I understand why George and Tracy don't want to release their ideas about thyreophorans until they get a relatively air-tight case. If you release your ideas piecemeal, it certainly leaves you wide open for having them picked apart and having the peanut gallery showering all manner of criticisms on you every step of the way.



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