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Re: David's Statements [Extended Version]



Mickey Mortimer (Mickey_Mortimer@email.msn.com) wrote:

<Dromaeosaurids lack pneumatized dorsals?! I know you don't
think Achillobator is dromaeosaurid (with its pneumatized
caudals(?) and dorsals), but plenty of dromaeosaurids have
dorsal pleurocoels. Deinonychus, Variraptor and
Saurornitholestes have pneumatic dorsals, as do the related
deinonychosaurs Bambiraptor and Unenlagia. Ornithomimids have no
pneumatized dorsals.>

  I stand corrected, my statements were more general. Am fairly
certain most of my statements were based on *Sinornithosaurus*
and *Gallimimus* (which don't seem to have very manu pneumatic
dorsals, but cervicodorsals or dorsosacrals do seem to be
pneumatic. Am also very certain that *Pelecanimimus* is more
pneumatic than most, and that ornithomimids are a reversal on
the tree, but must jump back into the lit. Am also curious is
anyone has Xabier Perez-Moreno's email, if he has one?

<Keep with the times (and rapidly changing phylogenetic trees)
man. :-) Avimimus used to be a Yandangornis+Pygostylia sister
group for a while until it settled back down as an alvarezsaurid
sister group. Still not mononykine though, as it lacks too many
alvarezsaurid synapomorphies.>

  I distrust polypositional taxa, where the newest phylogeny
drops these certain taxa in this brand new place, and _whomp!_
you get a new theory.

<I personally think Avimimus or therizinosauroid when I see the
ilium, but haven't done any studies yet.>

  This might be expected in a plesiomorphy: the degree to which
the ilia flare caudally and the degree to which the medial shelf
and the sacral "yoke" comprise this union or width may be more
key than the condition itself. Super-wide posterior pelvic canal
in *Segnosaurus* is interesting to note for such a large animal
(on the order of 28ft, my estimates). Interesting further to
note wide posterior pelves in *Chirostenotes* and the more
similar condition of the ilium in _these_ two.


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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