Re: Tyrannosaurus imperialis?

[Dinogeorge@aol.com]

In a message dated 98-06-22 17:31:57 EDT, tkeese1@gl.umbc.edu writes:

<< Are the ICZN rules on the web anywhere? >>

Try searching for keywords like "nomenclature" and "zoological nomenclature."

Regarding generic nomina dubia as type of family group names, ICZN says:

"Recommendation 64A. Type genus should be well known.--So far as possible, an
author who establishes a nominal family-group taxon should select as its type
genus a genus that is both well known and representative of the taxon."

and

"Recommendation 75E. Use of neotypes to clarify nomina dubia.--Neotypes should
be designated to clarify the application of names when their continued
existence as nomina dubia threatens the stability of other names; if, despite
the existence of a holotype, or a lectotype, or syntypes, it is not possible
to resolve a complex zoological problem, a zoologist should refer the case to
the Commission which may, by the use of the plenary power, set aside the
existing type material and designate a neotype."

The latter is the recommendation that was used to rename the type specimen of
Rioarribasaurus colberti to Coelophysis bauri, setting aside the original type
material of Cope. The ICZN could likewise be petitioned to designate neotype
material for the type species of Deinodon, Hadrosaurus, Ceratops, and so
forth, if and when better material (usually, topotypes) is discovered.

Since these are recommendations and not rules, they need not be strictly
adhered to. There's nothing that I can find in the ICZN that says one >cannot<
use a nomen dubium as a family-group type genus, only that one >shouldn't<.