Re: Dinosaur Genera List update #180

["Jaime A. Headden" <qilongia@yahoo.com>]

  David Marjanovic asks about *Huabeisaurus* and it's possible affinities. 
Though touted as a
possible titanosaur by the authors (Peng and Cheng, 2000), there are several 
features of the
animal that suggest a more "primitive" if general affinity, which I looked at a 
few nights ago
after a cursory examination:

  The slender- and shallowness of the scapular blade is found in diplodocids, 
for the most part,
and features of the scapula fail to satisfy a comparison to the 
Camarasauromorpha; the coracoid is
also similarly sub-ovate, rather than rectangular or circular. Likewise, the 
caudals are
amphicoelous, and the neural arches are not set cranially on their centra in 
the caudals. The
cervical vertebrae are perhaps the most diagnostic element, which are complexly 
pneumatized by
numerus camarae and subcamarae, a feature found only in diplodocimorphs. This 
is true of *Jobaria*
as well. The neural spines also bear lateral fossae, restricted to 
non-camarasauromorphan
eusauropods higher than mamenchisaurs. (That clade really coulkd use a name, I 
think, as it is
functionally diagnostic and immenently supportable in various analyses. Maybe 
"Pleurocamarae" or
something...

  This suggests (nay, indicates) that *Huabeisaurus* is not a titanosaur. On 
the contrary, it
suggests that *Huabeisaurus* (as well as *Jobaria*) are diplodocimorphs, the 
latter a very basal
one perhaps.


=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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