ABSTRACT
Progress in phylogenetics that started in the 1950s allowed the development of phylogenetic nomenclature (PN). Some basic ideas, like the emphasis on crown- and total groups, were formulated by Hennig, but developments in PN accelerated a few decades later in the late 1980s. Under PN, taxon names can be defined in three main ways: using a node (of which crowns are a special case), branches (including total groups) and apomorphies. This last kind (apomorphy-based definitions) is problematic to the extent that it is less precise (more ambiguous) because characters can be interpreted in various ways.
Work on the PhyloCode only started in 1997 and a first draft was posted on Internet in 2000. It was initially supervised by an advisory committee, but, in 2004, this responsibility was transferred to the newly formed International Society for Phylogenetic Nomenclature (ISPN). The PhyloCode took effect in April 2020, with the simultaneous publication of Phylonyms, the monograph that includes the first set of names established under that code.
The PhyloCode aims at regulating the names of all biological organisms and is partly inspired by the draft BioCode. Given various problems linked with species (nomenclatural problems linked to binominal nomenclature, the vague ontology of species and the fact that many species concepts do not imply monophyly), the current version of the PhyloCode does not regulate species names. However, it can be used to name clades that approximate the delimitation of currently recognized species, or even infraspecific clades.
