Dear all,
Ignore if this seems very basic for you, but mistakes are being made out there. If you are uncertain about the terminology please be careful with using 'nomen nudum' for species names. I've seen it appear in recent abstracts, and used multiple times in a checklist, when the designation was not correct. It's simply a name published 'naked' without the basic details required by the Code that make a name usable as a label in taxonomy. If we apply it wrongly the original author is entitled to feel somewhat annoyed (fortunately mostly these authors will no longer be with us).
A nomen nudum is a PUBLISHED NAME that lacks a description or indication of what the taxon is. We can do nothing further with it. Usually it gets published by accident or carelessness. By definition unpublished names CANNOT be nomina nuda, and the names of described published taxa CANNOT be nomina nuda.
If a work is unpublished, such as many old non-European theses are unpublished, the names of taxa described in the thesis are NOT nomina nuda, they are simply unpublished and don't enter nomenclature AT ALL, unless published subsequently (which may well happen), whereupon the later name publisher would be the name's new author.
If a description is inadequate by today's standard and the type is missing, the taxon name is NOT a nomen nudum, but it might be regarded as a nomen dubium in the opinion of a particular author. A nomen dubium is very different and is a subjective categorisation in taxonomy without any particular significance for nomenclature.
To end with an example. The great McIntosh wrote long rambling descriptions that might be quite useless - those 'fully clothed' names are NOT nomina nuda of course, whereas he also slipped stark-naked into his publications mentions of names that he was going to describe later - YEESS, those were his nomina nuda. It's easy.
Thank you,
Geoff
