Re: SEGNOSAUR 2

[Jeffrey Martz <martz@holly.ColoState.EDU>]

> The kind of basisphenoid that
> _Erlikosaurus_ had is not known in any other dinosaur groups, so it is fair to
> call it a segnosaur autapomorphy even if we have only one segnosaur specimen
> that displays it.

     I don't follow that reasoning at all.  If that kind of basisphenoid
is found in a larger group that also has a number of other features in
common with it, it may be fair to say that it is a segnosaur-whatever
symPLEISIOMORPHY.  But if _Erlickosaurus_ is the only skull known to
have it in a family where none of the other known specimens have
skulls, how can you possibly determine if that the feature
is a segnosaur or _Erlickosaurus_ autapomorphy?  If _T.rex_ was the only
tyrannosaur known with a skull would you say that rostrolaterally facing
eyes were a tyrannosaur autopomorphy?    
       
LN Jeff