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Re: Therizinosauroid apomorphies



On Wed, 5 Apr 2000 Dinogeorge@aol.com wrote:

> In a message dated 4/4/00 7:06:51 PM EST, tmk@dinosauricon.com writes:
> 
> << Since Segnosauria hasn't been phylogenetically defined, there is no way to
>  show that it is truly a synonym of Therizinosauria, anyway. Segnosauria is
>  still open to phylogenetic definiton. >>
> 
> This can easily be rectified. I would prefer to make Segnosauria as inclusive 
> as possible, so that Therizinosauria would >not< be a synonym (unless it was 
> already defined this way--so many def's kicking around these days, it's hard 
> to keep them straight). Segnosauria: all maniraptorans more closely related 
> to Segnosaurus than to (fill in your favorite segnosaur outgroup here).

I believe that's pretty much how Therizinosauria was defined (with
_Therizinosaurus_ as the anchor instead of _Segnosaurus_, of course).

Other possibilities would be {_Beipiaosaurus_ + _Segnosaurus_},
{_Segnosaurus_ > _Beipiaosaurus_}, both of which fit the traditional usage
fine. On the more inclusive side, there's {_Segnosaurus_ + _Oviraptor_}, a
clade which really could use a name, but I dunno if "Segnosauria" is the
right one ... calling _Oviraptor_ a segnosaur doesn't feel right. Ditto
for _Ornithomimus_ for those who consider therizinosaurs ornithomimosaur
relatives.

-- T. Michael Keesey .................................. <tmk@dinosauricon.com>
   My Worlds (including The Dinosauricon) ... <http://dinosauricon.com/keesey>
   AOL Instant Messenger ........................................ <Ric Blayze>