The PhyloCode only governs the naming of clades,[7] not of paraphyletic or polyphyletic groups, and only allows the use of specimens, species, and apomorphies as specifiers (anchors).
[8] Unlike rank-based nomenclatural codes (ICN, ICZN, ICNB), the PhyloCode does not require the use of ranks, although it does optionally allow their use.
In contrast, under phylogenetic nomenclature, the content of taxa are delimited using a definition that is based on phylogeny (i.e., ancestry and descent) and uses specifiers (e.g., species, specimens, apomorphies) to indicate actual organisms.
Once implemented, the PhyloCode will be associated with a registration database, called RegNum, which will store all clade names and definitions that will be considered acceptable.
The ISPN membership elects the Committee on Phylogenetic Nomenclature (CPN), which has taken over the role of the advisory group that oversaw the earlier stages of development of the PhyloCode.
The Second International Phylogenetic Nomenclature Meeting took place from June 28, 2006, to July 2, 2006, at Yale University (New Haven, Connecticut, U.S.).
[18] The theoretical foundation of the PhyloCode was developed in a series of papers by de Queiroz and Gauthier,[19][20][21] which was foreshadowed by earlier suggestions that a taxon name could be defined by reference to a part of a phylogenetic tree.
However, many rules in the PhyloCode have no counterpart in any code based on taxonomic ranks because of fundamental differences in the definitional foundations of the alternative systems.
Note that the PhyloCode does not govern the names of species, whose rules of availability, typification, etc., remain regulated by the requisite traditional Code of Nomenclature.