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Syntarsus



Sender: "T. Mike Keesey" <tmkeesey@wam.umd.edu>
 > 
 > Okay, there are two species - S. kayentakatae and S. rhodesiensis. The
 > former has paired crests, the latter doesn't. Other members of its family
 > (Coelophysidae) include Coelophysis (non-crested and small), Liliensternus
 > (large, crested?), and Dilophosaurus (large and crested). 
 > 
 > It seems like Syntarsus is a paraphyletic species, with S. kayentakatae
 > closer to Dilophosaurus than to S. rhodesiensis! Is this the case?

Probably not.  Crests are dratted poor characters to use for phylogenetic
analysis.  They tend to change rapidly, and unpredictably, and certainly
evolved many times in Theropoda.
 > 
 > Possibly I'm missing something. Did the common ancestor of the
 > Syntarsus and Dilophosaurus have crests, and then S. rhodesiensis lost
 > them? Or are the crests a case of convergent evolution?

Something like that.
 > what happens to the
 > name? If S. kayentakatae id the type species, I guess S. rhodesiensis
 > could be sunk into Coelophysis. Otherwise, wouldn't a new name be needed
 > for S. kayentakatae?

S. rhodesiensis is the type species.

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.