RE: Ceratops (was RE: Pterosaur diversity (was: Re: Waimanu))

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Taylor wrote:

> Sometimes it's too late.  By the time we had enough new genera that
> _Titanosaurus_ was no longer uniquely diagnosable, it was 125 years
> old.  By the time we figured out that procoelous caudals are not
> synapomorphic for "titanosaurids", Titanosauridae had been established
> for the best part of a century.  For that century-and-a-bit,
> _Titanosaurus_ and Titanosauridae were good, useful taxa.  That they
> are now rightly deprecated doesn't change the fact that they were
> historically useful.

I agree - but the word "were" is the crux of this argument.  When a taxon is 
no longer useful, it is probably better to discard it - instead of resorting 
to heroic efforts to keep it alive.

> ... but the draft PhyloCode also, of course, also requires that taxa
> (i.e. clades) that are named after genera include those genera:

This could be harder to prove.  After all, unless an explicit etymology is 
provided for each clade, it is open to interpretation whether it is named 
*after* a given genus.  For example, we know that when Titanosauria was 
first named (was it by Bonaparte and Coria, 1993?) it was ultimately named 
after _Titanosaurus_; but unless this is explicitly stated in the paper, the 
name could just be a descriptive term in its own right ("titan lizards").  
Same for Ceratopsia.

We know that Dinosauria was not named after a genus, because Owen gave 
reasons for why he came up with this name.  But for all intents and 
purposes, Titanosauria and Dinosauria could be treated the same way because 
neither were explicitly tied to a specific genus.

Family-level taxa are named after included genera because this practice is 
mandated by the ICZN.   But this is not the case for higher-level taxa (in 
zoological nomenclature, anyway).

> That says to me that it's bad PhyloCode practice, too, to make a name
> based on a genus whose affinities can't be rigorously established.

Yes.  After all, rigorously establishing the affinities of taxa is the main 
purpose of PT.

Cheers

Tim