Re: nomenclatorial problems

["Nicholas J. Pharris" <pharrinj@PLU.edu>]

On Mon, 22 Apr 1996, King, Norm wrote:

> introduction of _Rioarribasaurus_ has indeed "renamed"
> much of the material formerly called _Coelophysis_.

However, if we were not allowed to split up ill-founded or
"wastebasket" genera, almost every large theropod would have to be
called _Megalosaurus_, and all of the nearly 40 species of cats would be
subsumed under the name _Felis_ (13 or so genera is closer to the mark).

The moral of the story is:  Don't name a genus unless you're absolutely
*certain* it can be distinguished from all others, and don't refer good
specimens to bad genera unless you can be *certain* they are from the
same type of animal.

> It takes an expert to figure it out, and even
> the experts have had trouble keeping things straight.

I am by no means an expert, and I have little trouble figuring it out.
Most dinosaur genera (especially more recently-named ones) have no such
nomenclatural problems.  And I think the few that do have convoluted
histories provide a good example of how difficult it is to determine and
compare the characteristics of such long-dead animals.


> I wonder if there are standards for deciding where to draw the line
> between genera among ceratosaurs (or coelophysids, more specifically--so
> to speak ;-)), hadrosaurines, and lagosuchids, as "random" examples?

Unfortunately, there are no such standards (and it would be difficult to
erect standards, as every pair of sister species is itself a taxon).  The
species is the only taxonomic grouping with a rigid definition (and the
only one even capable of having such a definition).  Anything above that
level is up to the author.


> maybe people could have foreseen that
> designating a new genus for the Ghost Ranch coelophysid material would
> have caused a counter-productive furor.

If _Rioarribasaurus_ had been erected purely because of the inadequacy of
the _Coelophysis bauri_ type material, I would say the old name should
stay.  But if the Ghost Ranch animals really are different from the type
species, then _Rioarribasaurus_ should stand.

> Norman R. King


Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8206
PharriNJ@PLU.edu