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Ceratosaur stuff

Jaime Headden wrote:

> It was a very small animal, as is obvious from Luis Rey's painting of 
> the Auca Mahuevo site; the sauropods there could squat and kill these 
> critters, even when they were full size.

Perhaps that explains the cranial horns of _Carnotaurus_ and _Majungatholus_
- a deterrence against being sat on by angry sauropods!

Mickey Mortimer wrote:

> And the metatarsus lacks the slender second and fourth metatarsals seen 
> in  several abelisauroids.  Metatarsal IV is actually much broader than 
> III  (sort of like troodontids).  So this settles the debate as to 
> whether abelisaurids have this character, allowing it to be used to 
> group Noasaurus, Masiakasaurus and Velocisaurus in a Noasauridae to the 
> exclusion of abelisaurids.  

Which state is primitive?  Or are both metatarsal proportions derived
relative to coelophysoids and ceratosaurids?  In other words, can you be
certain that the proportions seen in _Noasaurus_, _Masiakasaurus_ and
_Velocisaurus_ are not primitive for the Abelisauroidea?

> Whether Ligabueino, Elaphrosaurus, Laevisuchus or  Chuandongocoelurus 
> are noasaurids too, or somewhere else in the Ceratosauria remains to be 
> clarified. 

_Chuandongocoelurus_?  Haven't heard anything on this fellow for quite a
while.  What makes you think it could be an abelisauroid? - thereby making
it the earliest (Middle Jurassic) member of the clade.  (Assuming
_Piatnitzkysaurus_ is a basal tetanurine, not an early abelisaur as avered
by Currie.)

By the way, many thanks to Mickey and Mike for the juvenile theropod info.
Much appreciated.



Timothy J. Williams, Ph.D. 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 9359