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Rajasaurus roundup



Hi,
A few days back Nick Gardner mentioned that the paper on _Rajasaurus_ was 
officially published.  That is indeed the case, as I have a copy in my hands.  
It is dated August 15, 2003, and if past experiences are any indication, it may 
be a little hard to get.  I know that many onlist are likely to request a pdf 
file, but I'm afraid that I don't have one.  As far as I know, the University 
of Michigan doesn't distribute pdf copies of their Contributions online, but I 
could be wrong.  

So, for the sake of those that might have a little trouble obtaining this 
thing, I'll summarize briefly.  Nick already posted the citation and abstract, 
so no need to be redundant.

The holotype (Geological Survey of India, Calcutta, GSI No. 21141/1-33) is a 
partial skeleton consisting of a braincase, cervical centrum, partial dorsal 
vertebrae, sacrum, partial caudal vertebrae, partial scapula, partial ilia, 
left proximal pubis, right femur, left distal femur, right distal tibia, right 
proximal fibula, right and left metatarsal II, and right metatarsal IV.  Casts 
of some of these elements are also housed at the University of Michigan Museum 
of Paleontology (UMPP 9085).  The specimens come from Temple Hill, near 
Rahioli, and the holotype is regarded as representing a single individual.  The 
specimen was preserved within a melange of titanosaur bones, and was excavated 
from 1982-1984.  The specimens were found in the Maastrichtian Lameta Formation.

Wilson et al. note that the ilia and sacrum described as _Lametasaurus_ by 
Matley (1923) match the holotype of _Rajasaurus_ in their heavy construction 
and strongly divergent preacetabular process, but any conclusive referral is 
avoided at this time.

_Rajasaurus_ is diagnosed by a median nasofrontal prominence, with the frontals 
forming only the posterior rim of the prominence; anteroposteriorly elongate 
supertemporal fenestrae, with length approx. 150% transverse breadth of 
frontal; and robust ilium with transversed ridge separating the brevis fossa 
from the acetabulum.

A 169-character phylogenetic analysis is presented.  While each character, 
including its first cladistic authorship, is listed in an appendix, tree 
statistics will be discussed in an upcoming paper that, barring the usual 
pitfalls of review, should hopefully be published soon.  Disagreeing with 
Sereno (1999) and Holtz (2000), but agreeing with Carrano et al. (2002) and 
some others, the new analysis finds _Ceratosaurus_ and abelisauroids sharing a 
more recent common ancestry with Tetanurae than with _Coelophysis_ and kin.  
Additionally, the analysis also finds an unnamed "Niger Taxon 1" as immediately 
basal to Abelisauroidea, and another unnamed "Niger Taxon 2" as an abelisaurid 
closely related to _Abelisaurus_, _Rajasaurus_, and _Carnotaurus_.  Perhaps 
most significantly, the new analysis also includes _Deltadromeus_, and finds 
this form to be a noasaurid!  It is placed in a trichotomy with _Noasaurus_ and 
_Masiakasaurus_.  However, it is best to be cautious with this placem!
 en!
!
t
 at this point, as only one character unites _Masiakasaurus_ and 
_Deltadromeus_: strongly reduced distal condyles of metatarsal IV.  One 
character, that's it.  As no coelurosaurs are included in the analysis, and 
Spinosauroidea and Neotetanurae are treated as OTUs, this needs to be tested 
further.

As Sereno (1998) and Padian et al. (1999) both formulated their respective 
cladistic definitions based on a monophyletic Ceratosauria including 
_Ceratosaurus_ and _Coelophysis_, the authors recognize that the name 
Ceratosauria is periously close to falling into synonymy.  Therefore, they 
accept Padian et al.'s (1999) definition (all neotheropods more closely related 
to _Ceratosaurus_ than to Neornithes).  Neotheropoda (node-based), Tetanurae 
(stem), and Ceratosauria (stem) are configured into a node-stem triplet, as is 
Abelisauroidea (node), Abelisauridae (stem), and Noasauridae (stem).  
Additionally, new definitions of the latter three taxa are presented: 
Abelisauroidea (_Carnotaurus_, _Noasaurus_, their most common ancestor and all 
descendants); Abelisauridae (all abelisauroids more closely related to 
_Carnotaurus_ than to _Noasaurus); and Noasauridae (all abelisauroids more 
closely related to _Noasaurus_ than _Carnotaurus_).

Let the arguments begin.

Steve

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******************************************************
Stephen Brusatte
Geophysical Sciences
University of Chicago
Dino Land Paleontology-http://www.geocities.com/stegob
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