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Re: _Turanoceratops tardabilis_
On Mon, 26 Feb 1996, Adam Yates wrote:
> I'm a little confused by the above statement. How can all known members
> of a taxon form a monophyletic clade yet the taxon still be paraphyletic?
Welcome to the weird world of Olshevskian logic!
> Unless of course you are intending to place any future discoveries of
> "stem" ceratopids or neoceratopians into Protoceratopidae. What would be
> the justification for this? Wouldn't it be simpler to place stem
> ceratopids in Ceratopidae and stem neoceratopians a plesions outside of
> Neoceratopia (if Neoceratopia has a node based definition) or outside of
> Ceratopidae + Protoceratopidae, within the Neoceratopia (if a stem based
> definition is used).
Hmmm. This sounds suspiciously familiar. Ah, Yes. That's it. I spent
about a week going over this very sort of argument with George regarding
herrerasaurs, theropods, and hypothetical stem sarcodinosaurs.
I agree with you. Basal neoceratopians, were they ever to be found and
recognized as such, could not be placed _in_ the Neoceratopsidae if one
defines this as, say, all descendants of the last common ancestor
of _Leptoceratops_ and _Triceratops_, because the more basal neoceratopians
would not have been descended from that common ancestor!
Even if one uses the old character-based system, basal neoceratopsians
would be excluded because they would necessarily lack certain features
shared by Ceratopidae and Prtoceratopidae.
> Adam Yates
Pacific Lutheran University
Tacoma, WA 98447
"If you can't convince them, confuse them." -- Harry S. Truman