Note: “PhyloCode”

Cladistic analyses produce either pure cladograms, phylograms with distinctive branch lengths, or time-calibrated cladograms (chronograms, timetrees). In any case, only clades with robust support should be given names. In zoological taxonomy, the rules for applying clade names are traditionally defined by the International Code of Zoological Nomenclature (ICZN). The rules only pertain to clades of lower hierarchical ranks (genera, tribes, and family groups), and strictly follow the principle of priority. ICZN stipulates that family-group and tribal names have fixed suffixes (-oidea, -idae, -inae, - ini, and -ina). Above superfamily level, clade names can be freely chosen. 

Orders of birds and fishes are traditionally indicated by the Latin suffix -(i)formes, while order names of mammals and invertebrates have no consistent pattern.

In 2019, a number of ICZN critics, objecting to the use of clade names that are burdened with ranks, released the International Code of Phylogenetic Nomenclature. Proponents of this PhyloCode want to get rid of imposed arbitrary ranks (aside from the genus level that has no fixed suffix and forms part of the binomial species name), arguing that ranks provide relative hierarchy-level information only within a given clade, but lack equivalence among clades. 

In the long term, zoologists should not tolerate the existence of two competing codes of nomenclature. A first step towards bridging existing differences might be the application of „temporal banding“. This approach allows ranks to be linked to evolutionary ages. 



Cantino PD, and de Queiroz K  (2020), International code of phylogenetic nomenclature (PhyloCode), version 6. (pdf)