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Re: Ceratops (was RE: Glishades ericksoni, ...)
Of course there's nothing stopping someone from including _Ceratops
montanus_ in a phylogenetic analysis. But this is not the same as
saying that there is a *good* reason for including _Ceratops
montanus_ in a phylogenetic analysis.
Your suggestion is just special pleading. _Ceratops_ is the
name-bearing genus for the Ceratopsidae, and therefore you are
pretending it's a useful OTU for a phylogenetic analysis. But it
isn't. The type material of _Ceratops montanus_ could belong to any
number of derived, brow-horned ceratopsians - including (as noted by
Ryan, 2007) _Albertaceratops_. In fact, decent cranial material that
was thought by Trexler and Sweeney (1995) to belong to _Ceratops
montanus_ was later assigned to _Albertaceratops_.
Including a deliberately phoney OTU like _Ceratops_ in a phylogenetic
analysis alongside valid OTUs (like _Albertaceratops_) defeats the
entire purpose of a phylogenetic analysis, which is to establish
relationships among taxa.
It's indeed a bad idea to include OTUs that are possibly paraphyletic
with respect to other OTUs in the same data matrix.
Of course there's an easy way to get around this: make a specimen-level
analysis, and put *Ceratops* in.