Apomorphy-based definition also pinpoints a node, and PhyloCode names prevent effective communication

Abstract

Acceptable methods of defining taxon (or clade) names in the draft PhyloCode, or so-called phylogenetic nomenclature, are “node based,” “stem based,” and “apomorphy based.” All of them define a clade name by pinpointing a node; whereas node-based and stem-based definitions require two or more taxon “specifiers” to define names, an apomorphy-based definition requires two specifiers of different types; namely, a single-taxon specifier and a character specifier. The taxon specifier in an apomorphy-based definition is completely different from the “type” in the Linnaean system. Taxon (or clade) names in the PhyloCode are characterized in two entirely different manners: One is a name that does not change, either in its orthography or in the contents of the taxon referred to by it (or its meaning) over time; the other is a name that is just like a pure mark and thus has no meaning. Communication through such PhyloCode names is very ineffective or impossible.