Re: Ceratopsian Systematics [was: Avaceratops and Ceratops (was Re: THE NEW I...

[Dinogeorge@aol.com]

In a message dated 1/26/00 1:12:26 PM EST, znc14@TTACS.TTU.EDU writes:

<< Actually, according to PT, "Ceratopidae" and "Ceratopinae" have
 never been defined. >>

Yes, but I think only recently, in Sereno's paper "A rationale for 
phylogenetic definitions, with application to the higher-level taxonomy of 
Dinosauria," N. Jb. Geol. Palaeont. Abh. 210(1): 41-83, Oct. 1998.

Ceratopsidae: Pachyrhinosaurus, Triceratops, their most recent common 
ancestor and all descendants

Ceratopsinae: All ceratopsids closer to Triceratops than to Pachyrhinosaurus

Note that if Triceratops is outside "Chasmosaurinae," this definition of 
Ceratopsinae might exclude the chasmosaurines from the subfamily. And even 
the genus Ceratops, such as it is.

The ICZN takes the long view of definitions and diagnoses, including 
phylogenetic taxonomy: they're all just passing fads. Only the names are 
stable and will exist for as long as there is zoological taxonomy, not the 
groups nor their definitions, which change whenever there is a new 
classification paradigm.