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RE: Ceratops (was RE: Glishades ericksoni, ...)
Tim Williams wrote-
> But... we'll never know where _Ceratops_ sits in ceratopsian phylogeny.
> _Ceratops_ is *never* included in a phylogenetic analysis, because it is a
> nomen dubium.
> I'm not saying _Ceratops_ *should* be included in a phylogenetic analysis;
> I'm only saying it *can't* be. This simple fact makes it impossible to
> determine the content of Ceratopsidae if _Ceratops_ is a specifier. For
> example, what if _Avaceratops_ comes out as a sister taxon to the
> Chasmosaurinae+Centrosaurinae clade. Is _Avaceratops_ a ceratopsid? We could
> only know this if _Ceratops_ is also included the analysis. But it isn't...
Er... there's nothing stopping someone from including nomina dubia in
phylogenetic analyses. It will just make a polytomy in the range of all the
taxa it cannot be distinguished from. And if that polytomy is within the
Chasmosaurinae+Centrosaurinae clade, then using Ceratopsidae for that clade is
> IMHO, the best solution is to abandon Ceratopsidae altogether. We've
> abandoned other family-level names that have been deemed to be based on
> dubious genera (Deinodontidae, Trachodontidae, Titanosauridae, etc), so why
> not abandon Ceratopsidae too? Having a definition of Ceratopsidae that
> includes _Ceratops_, for the sole purpose of maintaining the name
> Ceratopsidae, strikes me as special pleading.
My preference would be to only abandon names if the eponymous taxon isn't
necessarily located within that clade. "Dubious" is just too subjective a
notion. Of course this requires actual hard work and exhaustive comparison
instead of just saying "Taxon X is only based on one bone whose original
diagnosis is no longer valid- it's undiagnostic." Has anyone actually tried to
compare Ceratops to other related taxa? I know they haven't for Deinodon, for
The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with