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Re: Forster's papers on Triceratops
Stan Friesen wrote:
> Based on Geroge Olshevsky's report, it appears as if she rejected
> sexual dimoprphisms for T. horridus/prorsus because _T. horridus_
> is much more common.
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-
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. :-) Greg Paul's _PDW_ has a nice analogy for
this kind of dilemma using his "leopards and lions" scenario.
> I do not think this is conclusive, at least if _T. horridus_ is
> the female morph. In an animal with a harem type herding system
> females may well be substantially more common than males. I am far
> more inclined to this view than to the idea of two such similar
> species being sympatric.
Don't forget about about the third one - _Diceratops hatcheri_.
IMHO it would also qualify as a sympatric species.