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Re: Type material: does it have to be pretty?



Phillip Bigelow wrote (11/13/97; 7:41p):

>>Another thing that I want to know about is whether a type specimen
>>can be replaced if a much better specimen is found?

>No. Provided that the crappy material is "diagosable" of something
>never before described, then it stays the type (holotype, actually).

>If the crappy material is later found not to have been diagnostic
>of a unique critter, then it ceases to be a valid taxon (provided
>that someone publishes this fact). The key is diagnosability,
>not completeness.

There is another solution to the problem of non-diagnosability in 
holotypes.  A neotype could be designated.  A neotype is (from the 
International Code of Zoological nomenclature) another specimen 
designated "to be the type (neotype) of a nominal species-group taxon if 
no holotype, lectotype, syntype, or prior neotype is believed to exist."

This is what should have been done for Coelophysis bauri (was that the 
species?), since the holotype was undiagnosable, rather than erecting a 
new genus (Rioarribasaurus) for the species.  The latter course, which is 
what actually happened until the Commission on Zoological Nomenclature 
was asked to intervene, left the better-known name in limbo and possibly 
referring to nothing identifiable.  Although at first glance it may 
appear that designation of a neotype would not be appropriate in this 
case (since a holotype existed), it had become clear that the holotype 
was inadequate.  This is what the Code recommends about such a situation:

"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."  (Recommendation 75E)

Recommendation 75B is this:  Before designating a neotype, an author 
should satisfy himself that his proposed designation does not arouse 
serious objection from other specialists in the group in question. 

I felt that the authors of Rioarribasaurus should have taken care to be 
sure that other systematists were likely to agree with their proposal.  
Foreseeing the considerable confusion and disagreement, the matter should 
have been brought before the Commission initially, which could then have 
designated a neotype for Coelophysis, thereby retaining stability in 
nomenclature and continuing to "honor" the originator of the concept (of 
C. bauri), who may have been operating according to professional 
standards in existence when the name was introduced.  (Well, maybe he 
wasn't, but we do strive for stability in established names.)  The 
Coelophysis affair demonstrates (or should have demonstrated) a situation 
in which a poor holotype could be replaced with a neotype.  Going through 
the process requires special effort, but in some cases it is the best 
approach.

I'm not arguing with Phillip--just supplying more information about this 
legalistic loophole to the sanctity of holotypes, and a commentary.  I 
know that several people on the dinosaur list don't agree with my 
position on Coelophysis.  So, what's new?  At least the subsequent action 
of the Commission supports my interpretation of the applicability of 
Recommendation 75E to such a situation.


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Norman R. King                                       tel:  (812) 464-1794
Department of Geosciences                            fax:  (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712                      e-mail:  nking.ucs@smtp.usi.edu