Guide to Naming

Properly naming organisms is often a tricky endeavour. While Linnean nomenclature has the virtue of universality, its reliance on latin and classical greek, and the complex rules by which the roots are combined, often make difficult the creation of appropriate and pleasing names.

Linnaean taxonomy
In his original work, in the XVIII century, Linnaeus classified life on Earth in a hierarchy with eight ranks: from the largest to the smallest, the   kingdom  (regnum), the   phylum   (also called division), the   class  (classis), the   order  (ordo), the   family  (familia), the   gen  us   and the species. A ninth (somewhat informal) rank, the domain, was added in the XX century above the kingdom. According to the modern taxonomy, humans belong to the domain Eukarya, the kingdom Animalia or Metazoa (animals), the phylum Chordata, the class Mammalia (mammals), the order Primates, the family Hominidae, the genus Homo and the species Homo sapiens.

As the complexity of classification increased further, in the XIX and XX century, more and more ranks were added, furtherly refining the process - first adding prefixes such as super-, sub-, infra-, and then with entirely new names. The complete chain becomes domain/superkingdom - kingdom - subkingdom - infrakingdom/branch - superphylum/superdivision - phylum/division - subphylum - infraphylum - microphylum - superclass - class - subclass - infraclass - parvoclass - legion - cohort - magnorder - superorder - order - suborder - infraorder - parvorder - superfamily - family - subfamily - supertribe - tribe - subtribe - genus - subgenus - section - series - superspecies - species - subspecies - infraspecies - variety - form.

Here is the complete classification of four example lifeform: humans, fruit flies, sunflowers and the bacterium E. coli (note that different authors can disagree about the details).

Clade names
Also see: Phylogeny

''Also see: PhyloCode, [http://www.ohio.edu/phylocode/art10.html art. 10] and [http://www.ohio.edu/phylocode/art11.html art. 11]''

The name of each category (taxon, plural form taxa) is obtained from a Latin or Greek word (e.g. Plantae = "plants") or from two or more words combined, either both Greek or both Latin (e.g. Tetrapoda = "four feet"). Even when the words are etymologically greek, they obey the rules of latin grammar, and they're always plural. Genera and species are treated according to special rules (see below). Often, the rank of degree higher than the genus has a particular ending, which can be found in this table:

Today, with modern cladistics, the ranks do not exist anymore, as clades can nest inside other clades that traditionally have the same rank (e.g. "Class" Aves into "Class" Sauropsida), or even in clades that traditionally have a lower rank (e.g. "Class" Aves into "Order" Saurischia). Because of this, most new clade names are not formed with special endings anymore. Since the taxonomic rank has been abandoned, monotypic taxa (those that include only one sub-category) should be avoided: if Cephalotaceae contains only Cephalotus, which contains only C. follicularis, this last one is the only name that should be kept, as the others are superfluous.

There still are some cases were special particles are employed: PhyloCode suggests the prefix "Pan-" for total groups (clades that include a living clade and every organism closer to it than to any other living clade), for example Pan-Aves or Pan-Insecta; more generically, "Pan-", "Holo-", "-formes" and "-morpha" make the base group more inclusive, while "Eo-", "Eu-", "Neo-" and "Proto-" make it more specific; "Pseudo-" and "Para-" would be used for similar, but entirely distinct groups. "Apo-" would be used for groups that exhibit a derived trait, for example if Spermatophyta plants are characterized by seeds, "Apo-Spermatophyta" would be the widest clade to include plants with seeds.

In some entries, any name of a clade is accompanied by the surname of the author who established it and the year of establishment: for example, "Mammalia (Linnaeus, 1758)" or "Amniota (Haeckel, 1866)".

Binomial nomenclature
The heart of both Linnaean taxonomy and modern phylogeny is the binomen (also called "binomial name" or "scientific name"): the double name that identifies a species. It always include both the genus and the proper species (and sometimes the subgenus, while superspecies are written in the same way as a normal species). They obey special rules different from the higher-ranking taxa names: The subspecies can be written after the species, obeying the same rules: it's Homo sapiens idaltu or H. sapiens idaltu or H. s. idaltu, but never Homo idaltu or idaltu alone. The subgenus, finally, in inserted between genus and species (if there is one), among parenthesis: for example, Bos (Bos) taurus. Diversely from the genus, even if it exists it can be ignored, writing only genus and species (Bos taurus).
 * 1) They always must be written italicized, while the others don't (except according to PhyloCode).
 * 2) Genus and subgenus are always capitalized, just like the other names, while species and subspecies cannot ever be capitalized.
 * 3) Species and subspecies can NOT ever be written alone: it's either Homo sapiens or H. sapiens, but never sapiens alone.

Botanical varieties are written like species, but introduced by "variety" or "var." e.g. Escobaria vivipara var. deserti.

Summary of possible forms to write a species:
 * Genus species
 * G. species
 * Genus species subspecies
 * G. species subspecies
 * G. s. subspecies
 * Genus (Subgenus) species
 * Genus (S.) species
 * G. (S.) species
 * Genus (Subgenus) species subspecies
 * G. (Subgenus) species subspecies
 * G. (S.) species subspecies
 * G. (S.) s. subspecies

Etymology
Traditionally, the roots used in genera and species names are latin or classical greek words; it's common that, while the genus is more specific, the species name is a generic latin adjective, such as communis (common), silvestris (wild), domesticus (domestic), borealis (northern), etc. This is not a rule, however. It's recommended that the literal meaning of the binomen is a description of the organism, but in fact any name is acceptable. It's usually recommended to avoid mixing both latin and greek roots in the same genus or species (nomen hybridum), though this is not an actual rule.

Recently, an habit has been born to use other languages in taxonomic terms: for example, Mei long is a chinese expression that means "sleeping dragon"; for chinese dinosaurs, the root long (="dragon") has all but replaced the greek root saurus (="lizard"). Shuvuuia comes from Mongolian, Balaur bondoc from Romanian; in many cases, latin endings are added, such as the -ia in Shuvuuia, but this doesn't always happen.

Often, one of the roots identifies the place of discoveries: for example, Bakonydraco, the "dragon of the Bakony Mountains". There is no specific rule concerning geographic places, except for euphony (the name should be fluid and pleasant); sometimes, the geographic origin is used as species, with the name of the place turned into a latin adjective with a suffix such as "-anus", "-icus" or "-ensis", for example Castor canadensis.

Another common choice for the species is the surname of a person, as in Apatosaurus louisae, after Louise Carnegie; in this case, a suffix such as "-i", "-ii" or "-ia" is added at the end, unless the surname ends with an "a", which is replaced by "-ae". The suffix "-ae" should be used for feminine names, and avoided for masculine ones.

Grammar
Whatever the etymology of the roots is, the binomen follows the rules of latin grammar. As detailed here, the names should use only the letters in the english alphabet (abcdefghijklmnopqrstuvwxyz) and no one else; moreover, it should be easily pronounceable, contain at least a vowel in each syllable and not contain long strings of consonants (though there are accepted names that violate this rule, such as Piatnitzkysaurus and Futalognkosaurus).

In the latin language, adjectives have a grammatical gender too, and they must have the same gender as the name they accompany. The basic form given by vocabularies is the masculine form, usually ending in "-us" or "-is"; as a rule of thumb, adjectives that end in "-us" become "-a" when feminine, and "-um" when neuter; those who end in "-is" stay "-is" when feminine and become "-e" when neuter; those who end in "-er" become "-ra" when feminin and "-rum" when neuter. While there are several exception, this rule holds true in most cases. For this reason, Linnaeus' Fringilla domestica could not become Passer domestica, but rather Passer domesticus, as "passer" is a masculine word.

List of words
NOTE: the words given here are from two languages - greek and latin. They can be distinguished by the fact that greek words come with their transliteration in greek letters, for example "arctos (ἄρκτος)", while latin words are isolated, for example "ursus".