Re: Dilophosaurus and Syntarsus

["Steve Brusatte" <dinoland@mailcity.com>]

On Fri, 23 Jun 2000 23:34:45  
 Rob Gay wrote:
>I was just sitting around, wondering, beyond what the function of the large 
>crests in Dilophosaurus and the smaller crests of Syntarsus kayentakatae, if 
>any other more recently discovered theropods had such crests. My only real 
>main source of information is my copy of The Dinosauria, which (in my case) 
>was published in 1990. It also states that Dilophosaurus, Syntarsus et al. 
>are part of Ceratosauria, along with Ceratosaurus. It seems to me, from what 
>I've been able to get from the section, that there are not a whole lot of 
>similarities between Ceratosaurus and the rest of the group, beyond the fact 
>the it has horns, and some of the other "Ceratosaurs". Just wondering if 
>these animals were still grouped together, or has cladistics tackled this 
>grouping as well.

Well, Monolophosaurus and Cryolophosaurus also possessed similar crests.  
Monolophosaurus' crest was like that of Dilophosaurus, in that it ran across 
the skull length wise.  Cryolophosaurus' crest, on the other hand, went across 
the width of the skull, extending from one orbit to the other.  

Monolophosaurus did belong to the Ceratosauria, while there is considerable 
debate on where Cryolophosaurus should be placed.  In his 1994 paper William 
Hammer said that Cryolophosaurus COULD be a ceratosaur with features convergent 
with those of some of the large tetanurans.  Today, he says that it is likely 
that Cryolo was a tetanuran.  

We discussed Cryolophosaurus' evolutionary history about a month ago.  To read 
more about it go to Dino Data's Paleozoica magazine at http://www.dinodata.net  
Click on the article about William Hammer and Antarctica's dinosaurs.

Steve

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Steve Brusatte-DINO LAND PALEONTOLOGY
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