Re: Forster's papers on Triceratops

[Stan Friesen <swf@ElSegundoCA.NCR.COM>]

From: "Tim Williams" <T.Williams@cclru.randwick.unsw.edu.au>
 > This rationale has also been used to differentiate two _Allosaurus_ 
 > species in the Morrison.  There are two morphs (of equal 
 > stratigraphic age), one more robust than the other, but one (and I 
 > can't remember which) predominates overwhelmingly in the Cleveland-
 > Lloyd Quarry. 
 > 
 > Either there were two sympatric species (or two genera according to 
 > Bob Bakker, the last I heard) or them male allosaurs in Utah had one 
 > doozy of a harem.  :-) 

There is another alternative.

In some species the males and females only remain together in the
breeding season, and the rest of the time they lead separate lives.

Perhaps Allosaurus behaved this way.  The the C-L quarry would be
sampling the female flock.

 > Don't forget about about the third one - _Diceratops hatcheri_.  
 > IMHO it would also qualify as a sympatric species. 

True, and that might be a problem.

We need some more work on ecological differentiation of the three forms.

[Though if one of the forms is *really* rare it may not actually
be local to the area, except perhaps seasonally].

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

The peace of God be with you.