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RE: Ceratops (was RE: Glishades ericksoni, ...)

Paul P <turtlecroc@yahoo.com> wrote:

> Nah. Ceratopsidae is a great name for that clade because, 
> again, Ceratops is likely a basal form, i.e. near the root
> of Centrosaurinae + Chasmosaurinae,

Yep, _Ceratops_ may indeed be "near the root of Centrosaurinae+Chasmosaurinae". 
 But is _Ceratops_ inside or outside this clade?  This is what I'm driving at.

Because unless _Ceratops_ is actually *within* the 
Centrosaurinae+Chasmosaurinae clade, then it is NOT a ceratopsid.  In other 
words, to qualify as a ceratopsid, _Ceratops_ must lie inside the clade 
specified by _Triceratops_ and _Centrosaurus_ (or _Pachyrhinosaurus_, depending 
on whose definition of Ceratopsidae you use).

_Triceratops_ is a chasmosaurine, and _Centrosaurus_ and _Pachyrhinosaurus_ are 
centrosaurines.  Thus, you cannot have either a non-chasmosaurine ceratopsid or 
a non-centrosaurine ceratopsid.  So there cannot be a "basal ceratopsid" that 
does not belong to either the Chasmosaurinae or Centrosaurinae.