Homonym (biology)

Inbiology,ahomonymis a name for ataxonthat is identical in spelling to another such name, that belongs to a differenttaxon.

The rule in theInternational Code of Zoological Nomenclatureis that the first such name to be published is thesenior homonymand is to be used (it is "valid"); any others arejunior homonymsand must be replaced with new names. It is, however, possible that if a senior homonym is archaic, and not in "prevailing usage," it may be declared anomen oblitumand rendered unavailable, while the junior homonym is preserved as anomen protectum.

For example:

• Cuvierproposed the genusEchidnain 1797 for thespiny anteater.
• However,Forsterhad already published the nameEchidnain 1777 for agenusofmoray eels.
• Forster's use thus haspriority,with Cuvier's being a junior homonym.
• Illigerpublished the replacement nameTachyglossusin 1811.

Similarly, theInternational Code of Nomenclature for algae, fungi, and plants(ICN) specifies that the first published of two or more homonyms is to be used: alater homonymis "illegitimate"and is not to be used unlessconserved(or sanctioned, in the case of fungi).

Example: the later homonymMyroxylonL.f. (1782), in the familyLeguminosae,is conserved against the earlier homonymMyroxylonJ.R.Forst. & G.Forst. (1775) (now calledXylosma,in the familySalicaceae).

Limits and exceptions

Under the zoological code, homonymy can only occurwithineach of the three nomenclatural ranks (family-rank, genus-rank, and species-rank) but notbetweenthem; there are thousands of cases where a species epithet is identical to a genus name but not a homonym (sometimes even occurring in the genus it is identical to, such asGorilla gorilla,termed a "tautonym"), and there are some rare cases where a family-rank name and a genus-rank name are identical (e.g., the superfamily nameRanoideaand the genus nameRanoideaare not homonyms). The botanical code is generally similar, but prohibits tautonyms.

Parahomonyms

Under the botanical code, names that are similar enough that they are likely to be confused are also considered to be homonymous (article 53.3). For example,AstrostemmaBenth. (1880) is an illegitimate homonym ofAsterostemmaDecne. (1838). The zoological code considers even a single letter difference to be sufficient to render family-rank and genus-rank names distinct (Article 56.2), though for species names, the ICZN specifies a number of spelling variations (Article 58) that are considered to be identical.

Hemihomonyms

Both codes only consider taxa that are in their respective scope (animals for the ICZN; primarily plants for the ICN). Therefore, if an animal taxon has the same name as a plant taxon, both names are valid. Such names are calledhemihomonyms.

For example, the nameEricahas been given to both a genus of spiders,EricaPeckham & Peckham, 1892, and to a genus of heaths,EricaL.

Another example isCyanea,applied to the lion's mane jellyfishCyaneaPéron and Lesueur and to the Hawaiian lobelioidCyaneaGaudich.

Hemihomonyms are possible at the species level as well, with organisms in different kingdoms sharing the samebinomial nomenclature.For instance,Orestias elegansdenotes both a species of fish (kingdomAnimalia) and a species of orchid (kingdomPlantae). Such duplication of binomials occurs in at least nine instances.

Animal	Plant
Adesmia muricata(Linnaeus, 1758)(a beetle)	Adesmia muricata(Jacq.) DC.(a legume)
Agathis montanaShestakov, 1932(a wasp)	Agathis montanade Laub.(the Mount Panié kauri, a conifer)
Baileya australis(Grote, 1881)(the small baileya moth)	Baileya australisRydb.syn.B. multiradiata(a desert marigold)
Centropogon australis(White, 1790)(the fortescue, a waspfish)	Centropogon australisGleason(a bellflower)
Cuspidaria cuspidata(Olivi, 1792)(a bivalve)	Cuspidaria cuspidata(M. Bieb.) Takht.syn.Erysimum cuspidatum(a wallflower)
Ficus variegataRöding, 1798(the true fig shell, a sea snail)	Ficus variegataBlume(the common red-stem fig)
Gaussia princeps(T. Scott, 1894)(a copepod)	Gaussia princepsH.Wendl.(a palm)
Orestias elegansGarman, 1895(a pupfish)	Orestias elegansRidl.(an orchid)
Tritonia pallidaStimpson, 1855(a nudibranch)	Tritonia pallidaKer Gawl.(an iris)

See also

• Glossary of scientific naming
• Isonym– Term in botanical nomenclature, an identical name based on the same type, but published later. Isonyms have no nomenclatural status (they are notvalidly published).

External links

Data related toList of valid homonymsat Wikispecies