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Re: Extinction - specific info
From: Tom Holtz <email@example.com>
> Hmm, let's see... Even if you lump as far as you can (put both
> dromaeosaurids as one genus, all the tyrannosaurids as one, take out
> Dyslocosaurus, put all the Triceratops line [D. hatcheri, T. horridus, and
> T. sp. 2] as one,
Hmm, what reasoning is behind seperating hatcheri from horridus?
My own perusal of the data seems to indicate that almost all
specimens of Triceratops fall within the range of variation of
a single species in the other genera of ceratopsians.
[I will reserve judgement on T. sp. 2 until I see the paper].
> both Thescelosaurus forms together, and Anatotitan into
> Edmontosaurus [although it is clearly a very derived form])
Actually the one aspect of the reclassification of Anatosaurus as
Edmontosaurus that bitehrs me is that three distinct species are
still recognized in *addition* to Anatotitan copei. They all seem
rather similar to me - and it seems odd that three such similar
species should live simultaneously *and* also last for so long a time
(since at least two of them are also known from pre-Lancian times).
I would think that there would be only one, or perhaps two, species
of Edmontosaurus (not counting Anatotitan).
The peace of God be with you.