In traditional nomenclature (TRAD) a type and a rank are attached to a taxon name. In phylogenetic nomenclature (PHYLO) a name is attached to a clade by an explicit definition (changes to the definition are prohibited without the express written consent of the International Committee on Phylogenetic Nomenclature). In PHYLO, the taxonomist has no discretion in circumscribing a taxon--a name’s phylogenetic definition and the accepted phylogeny determine a taxon’s circumscription. Thus, under PHYLO how the name has been previously applied (e.g., circumscription, character associations) cannot be considered when applying the name under a revised phylogenetic hypothesis. Taxonomists’ hands are effectively handcuffed by the explicit phylogenetic definitions. In TRAD the names are not shackled by explicit definitions. Thus classifications using this system are more flexible and able to accommodate new information with regards to relationships, while preserving historical usage as much as possible. Under the rankless PHYLO, the name of a taxon will not change (it may become synonymized) regardless of how shifts in hierarchical position (as a result of revised phylogenetic hypotheses) alter the content of the taxon (clade). Thus the name when used outside the context of a given phylogeny or taxonomy conveys nothing regarding set exclusivity. This contrasts sharply with TRAD where the names themselves convey broad information regarding set exclusivity. TRAD may not be perfect (no nomenclature can be) but it does an excellent job of communicating biodiversity information to the multiple constituencies that use taxon names. Why switch?

Key words: Linnaean nomenclature, phylogenetic nomenclature, taxon name definition, type-based nomenclature