Phylocode: a New System of Nomenclature

Features PhyloCode: A New System of Nomenclature

Peggy Robinson and the scientific community might ultimately Principles of the PhyloCode Thor Kommedahl, decide that the PhyloCode should become for the CSE Style Manual the sole code governing the names of taxa. Reference—The primary purpose of taxon Subcommittee At present the intent is to provide an alter- names is to provide a means of referring to A new code for naming organisms by explic- native system, not a replacement. taxa, as opposed to indicating their charac- it reference to phylogeny (ancestry and One fundamental characteristic that ters, relationships, or membership. descent),1 rather than on the basis of the distinguishes the PhyloCode from the Linnaean hierarchy of taxonomic categories conventional hierarchic nomenclatural Clarity—Taxon names should be unam- (species, genus, family, and so on), has been systems is its ranklessness. The PhyloCode biguous in their designation of particular proposed and is now under review. will cover the naming of clades and species, taxa. Nomenclatural clarity is achieved Proponents of the PhyloCode, a for- but in this system these terms refer not to through explicit definitions. mal set of nomenclature rules, posit that ranks, but to different kinds of biologic because species and clades (a term defined entities. As the preface to the PhyloCode Uniqueness—To promote clarity, each by the PhyloCode as “group[s] of species states, “both [clades and species] are prod- taxon should have only one accepted comprising a common ancestor and all ucts of evolution that are discovered, rather name, and each accepted name should of its descendants”1) are the constituents than created, by systematists, and both refer to only one taxon. of the “tree of life”, they should have have an objective existence regardless of explicit, unambiguous names that do not whether they are named”.1 Stability—The names of taxa should not change with time. The current nomencla- The starting date for the new code, change over time. As a corollary, it must tural systems based on Linnaean hierarchy which has not yet been decided, will coin- be possible to name newly discovered taxa (such as the International Code of Botanical cide with the publication of a companion without changing the names of previously Nomenclature2 and the International Code of volume providing definitions of widely used discovered taxa. Zoological Nomenclature3) do not boast such clade names. immutability; a clade or species name may The advisory group coordinating work on Phylogenetic context—The PhyloCode be changed on the basis of considerations of the PhyloCode is seeking comments and is concerned with the naming of taxa and rank or genus assignment even if the clade ideas concerning this proposal from as many the application of taxon names within a or the species itself has not changed. people as possible. If you are interested in phylogenetic context. The PhyloCode is based on ideas present- this subject, you are encouraged to review ed in the literature since the late 1980s and, the current draft of the PhyloCode and to The PhyloCode permits freedom of taxo- more formally, on the outcome of a work- make your views known by communicating nomic opinion with regard to hypotheses shop held at Harvard University in August directly with the PhyloCode advisory com- about relationships; it only concerns how 1998. The draft proposal covers only the mittee or by joining the PhyloCode discus- names are to be applied within the context naming of clades. Rules governing species sion group. of a given phylogenetic hypothesis. names will be added later. As a temporary measure, Linnaean binomial nomenclature References Source: PhyloCode. Division 1. Principles. is used in the draft PhyloCode where species 1. Cantino PD, de Queiroz K. PhyloCode: a phyloge- www.ohiou.edu/phylocode/principles.html names are needed. netic code of biological nomenclature [draft document]. (11 December 2001) The form that species names should take www.ohiou.edu/phylocode/printable.html (11 December (reproduced with permission) in the PhyloCode is controversial. A 1999 2001). article in the journal Systematic Biology4 2. 16th International Botanical Congress. International 4. Cantino PD, Bryant HN, de Quieroz K, Donoghue presents 13 possibilities for naming species code of botanical nomenclature (St Louis code). MJ, Eriksson T, Hillis DM, Lee MSY. Species names phylogenetically and compares these meth- Regnum vegetabile 138. Greuter W, chairman. in phylogenetic nomenclature. Syst Biol 1999;48: ods with each other and with the Linnaean Konigstein (Germany): Koeltz Scientific Books; 2000. 790-807. system. 3. International Commission on Zoological The PhyloCode has been designed so Nomenclature. International code of zoological Note: The information in this article is based that it can be used concurrently with the nomenclature. Fourth ed. London: International Trust on material available at the PhyloCode Web existing nomenclatural codes, although for Zoological Nomenclature; 1999. site: www.ohiou.edu/phylocode/.

52 • Science Editor • March – April 2002 • Vol 25 • No 2