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Nqwebasaurus, maybe NOT an African ornithomimosaur



Very cool to see this described in more depth.  Unfortunately, I'd recommend 
taking the phylogenetic position with a HUGE grain of salt.  Previous Choiniere 
analyses have been extremely uncoded, leaving huge swaths of data unknown when 
they could have been coded as one state or another.  In addition, at least the 
Haplocheirus analysis wasn't optimized in TNT right, as Choiniere et al. 
reported far too few trees which are longer and different than the 1,000,000+ 
most parsimonious trees their data actually generate.  While the Nqwebasaurus 
matrix is not available yet, only 176 trees are reported, and only 84 when it's 
constrained to be an alvarezsaur.  This suggests they made the same mistake 
while running TNT as last time.

Amusingly, this was all predictable back in 2010 when Nqwebasaurus was 
conveniently excluded from the Zuolong analysis after the Limusaurus analysis 
found it to be a basal ornithomimosaur 
(http://theropoddatabase.blogspot.com/2010/12/zuolong-new-basal-coelurosaur-from.html).

Mickey Mortimer

----------------------------------------
> Date: Fri, 15 Jun 2012 08:18:22 -0700
> From: bcreisler@gmail.com
> To: dinosaur@usc.edu
> Subject: Nqwebasaurus, an African ornithomimosaur
>
> From: Ben Creisler
> bcreisler@gmail.com
>
>
> A new online paper:
>
> Jonah N. Choiniere, Catherine A. Forster & William J. de Klerk (2012)
> New information on Nqwebasaurus thwazi, a coelurosaurian theropod from
> the Early Cretaceous (Hauteriverian?) Kirkwood Formation in South
> Africa.
> Journal of African Earth Sciences (advance online publication)
> http://dx.doi.org/10.1016/j.jafrearsci.2012.05.005
> http://www.sciencedirect.com/science/article/pii/S1464343X12001082?v=s5
>
>
> We performed additional preparation on the holotype skeleton of
> Nqwebasaurus thwazi and discovered new skeletal material from the
> holotype. We describe this material, which includes a maxilla with
> small, conical, unserrated teeth as well as bones of the braincase, as
> well as parts of the holotype postcranial anatomy that were previously
> poorly documented. We incorporate this new anatomical information into
> a broadly sampled matrix designed to test theropod relationships. Our
> phylogenetic results hypothesize that Nqwebasaurus is the basalmost
> ornithomimosaur, and recover numerous characters supporting this
> relationship, including features of the maxilla, frontal, dentition,
> axial skeleton, forelimb and hindlimb. Nqwebasaurus is the first
> African ornithomimosaur and the first Gondwanan member of this group
> known from articulated skeletal material, supporting the hypothesis
> that coelurosaurian groups were cosmopolitan during their early
> evolutionary history. The presence of reduced dentition and a gastric
> mill in Nqwebasaurus strongly suggest that this taxon was herbivorous.