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Re: Caudipteryx: My Reflections on the Postcranium [was: Details on....]



Jaime Headden wrote-

>   One thing I noted is that the type and paratype (NGMC 97-4-A
> and 97-9-A, respectively) and the type of *C. dongi* (IVPP V
> 12344) have slender distal chevrons that are seldom
> craniocaudally longer than they are deep, yet in BPM 0001 and
> IVPP V 12430, they resemble the condition in *Nomingia,* where
> they are shallower, longer craniocaudally, and resemble the
> ventral blade that Barsbold et al., (2000a, b) describe.

Although what you describe would be more evidence to support my hypothesis
C. dongi is synonymous with C. zoui, I cannot see it in the figures.  The
last six or so chevrons of NGMC 97-9-A are shallow and craniocaudally
elongate with a ventral blade.  The chevrons of BPM 0001 look extremely
similar.  The last few easily visible (directly below and above the crack in
the matrix) are blade-like and craniocaudally elongate.  I cannot see the
distal chevrons of IVPP V 12430 in enough detail to determine their
morphology.  No Caudipteryx specimen shows the morphology of Nomingia where
distal chevrons are rectangular with very little or no ventral expansion.

>   ... also appears to bear several striations and logitudinal
> ridges on its lateral surface, as does *Microvenator.* These
> ridges are present on _all_ specimens.

Interesting observation.  I just figured they were scars for articulation of
the sacral ribs.  Apparently they are on the lateral surface though.  I
disagree that they are present in Microvenator however (at least not
noticible in Makovicky and Sues 1998 figure or the photo at the AMNH
website).

>   Well, I'd say slightly curved, concave cranially, but that's
> my eye!

Hmm.  Yes, slightly cranially concave, which is why I said _almost_
straight.  This is difficult to judge in some theropods due to the convex
ilial peduncle and cranial pubic foot, which often make pubes look more
concave anteriorly than they really are.

Mickey Mortimer