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Re: Cryolophosaurus restoration



On Sun, 04 Jun 2000 13:45:26  
 Timothy Williams wrote:
>Steve Brusatte wrote:
>
>>In his 1994 and 1997 (and 1999, I believe) papers, Hammer stated that the 
>>some of the postcranial material may not belong to Cryolophosaurus.  As of 
>>today, he is basically saying that most of it (femur, vertebrae, ribs, hip 
>>bones) DOES belong to C. ellioti, but is leaving in the possibility of 
>>another Antarctic carnivore.
>
>In the original 1994 description, the authors (Hammer and Hickerson) do say 
>"it is possible these [postcranial] elements may not go with the skull, but 
>are clearly theropod and are the right size."  The femur and tibiotarsus 
>(which appears to be fused) are very ceratosaur-like, but the hip bones are 
>more in keeping with the tetanurine (especially allosauroid) affinities 
>suggested by the skull.

Yes, Hammer also said that it would be "unlikely" for two predators the size of 
Cryolophosaurus to be occupying the same environment, which would have been the 
case if these postcranial elements do not go with the skull.

The problem with Cryolophosaurus is that it's just too weird, even for dinosaur 
and paleontology standards.  Nobody's quite sure what it is, mostly because its 
odd mixture of characteristics and the fact that only one good Early Jurassic 
large theropod is known from Gondwanna.  

In their 1994 paper Hammer and Hickerson presented three possibilities for the 
evolutionary history and relationships of C. ellioti: 

1) A ceratosaur with features convergent with those of some of the large 
tetanurans

2) An early tetanuran that has some primitive features

3) Or, an early abelisaur

Though, when I talked to him a few months ago he said that it was definitely a 
tetanuran, which shares a few features with allosaurs but has a fairly 
primitive postcranial skeleton.  Therefore, he said, he wouldn't place it in 
the same family as Allosaurus.

Plus, he said, the links between Cryolophosaurus and Allosaurus are fairly 
unclear.  

So, I guess we're just as lost as when we started...

Steve

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