Diagnoses in zoological taxonomy and nomenclature

Abstract

The use of the term ‘diagnosis’ and of related terms (‘character’, ’description’, ‘definition’, etc.) in the two related fields of taxonomy and nomenclature is quite confusing. The purpose of this work is to propose an unambiguous terminology for these terms, and to discuss the use of diagnoses and related concepts in these two disciplines. In taxonomy, the different kinds of ‘diagnoses’ one uses provide different kinds of information about organisms, their characters and their relationships, and they should be used together rather than be mutually exclusive. In nomenclature, the current Rules of the Code that concern the use of ‘descriptions’ and ‘definitions’ are unclear. Articles 13.1.1 and 75.3.2 are ambiguous, as they allow both a ‘strict’ and a more ‘inclusive’ interpretation. Proposals are offered to improve them.