FIGURE 1 in Phylogeny, taxonomy and nomenclature: the problem of taxonomic categories and of nomenclatural ranks

FIGURE 1: Compulsory and optional nomenclatural ranks in zoological nomenclature, based on a hypothetic phylogeny. Nomenclatural ranks as designated in the upper line are as follows: C, classis; sC, subclassis; O, ordo; sO, subordo; SF, superfamilia; F, familia; sF, subfamilia; T, tribus; G, genus; sG, subgenus; S, species. Background colours indicate the nominal-series in which these ranks belong: blue, class-series; green, family-series; yellow, genus-series; salmon, species-series. Red stippled lines correspond to five major ranks that must be named in all cases, according to the guidelines here presented (see text). In the text, a taxon is designated by the letter(s) of its rank (upper line), combined with its number appearing in the tree. The reasons for naming these taxa are as follows: (1) star in circle, terminal taxa (species); (2) circles, taxa that must be named because they include several subtaxa; (3) squares, taxa that must be named, although they include only one species, because, acording to the phylogeny presented, they are sister-groups of taxa indicated by circles; (4) diamonds, taxa that are not supported by cladistic data, but that must be named for purpose of allowing the nomenclatural hierarchy to play its rôle of system of storage and retrieval of information (see text).