In biology, a homonym is a name for a
taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...
that is identical in spelling to another such name, that belongs to a different taxon.
The rule in the
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...
is that the first such name to be published is the senior homonym and is to be used (it is "
valid"); any others are junior homonyms and 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 a ''
nomen oblitum'' and rendered unavailable, while the junior homonym is preserved as a ''
nomen protectum''.
:For example:
:*
Cuvier
Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French naturalist and zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in nat ...
proposed the genus ''Echidna'' in 1797 for the
spiny anteater.
:*However,
Forster had already published the name ''Echidna'' in 1777 for a genus of
moray eels.
:*Forster's use thus has priority, with Cuvier's being a junior homonym.
:*
Illiger published the replacement name ''Tachyglossus'' in 1811.
Similarly, the
International Code of Nomenclature for algae, fungi, and plants (ICN) specifies that the first published of two or more homonyms is to be used: a later homonym is "
illegitimate" and is not to be used unless
conserved (or sanctioned, in the case of fungi).
:Example: the later homonym ''
Myroxylon
''Myroxylon'' is a genus of Fabaceae native to Latin America.
History
The first described species in this genus was '' M. balsamum.'' It was originally described in 1753 by Linnaeus as ''Toluifera balsamum'', based on a specimen collected ...
'' L.f. (1782), in the family
Leguminosae, is conserved against the earlier homonym ''Myroxylon'' J.R.Forst. & G.Forst. (1775) (now called ''
Xylosma
''Xylosma'' is a genus of flowering plants in the family Salicaceae. It contains around 100 species of evergreen shrubs and trees commonly known as brushhollies, xylosmas, or, more ambiguously, "logwoods". The generic name is derived from t ...
'', in the family
Salicaceae).
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, ''Astrostemma'' Benth. (1880) is an illegitimate homonym of ''
Asterostemma'' Decne. (1838). The zoological code has a set 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 called ''hemihomonyms''. For example, the name ''Erica'' has been given to both a genus of spiders, ''
Erica'' Peckham & Peckham, 1892, and to a genus of heaths, ''
Erica'' L.
Hemihomonyms are possible at the species level as well, with organisms in different kingdoms sharing the same binomial. For instance, ''Orestias elegans'' denotes both a species of fish (kingdom
Animalia
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in ...
) and a species of orchid (kingdom
Plantae). Such duplication of binomials occurs in at least eight instances.
See also
*
Glossary of scientific naming
This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see List of Latin and Greek words commonly used in systematic names. Note that many of the abbrevi ...
*
Isonym
An isonym, in botanical taxonomy, is a name of a taxon that is identical to another designation, and based on the same type, but published at a different time by different authors. Citation from that source follows:
That is, the later isonyms ...
– in botany, an identical name based on the same type, but published later. Isonyms have no nomenclatural status (they are not
validly published).
References
{{reflist, 33em
Botanical nomenclature
Zoological nomenclature
01
Taxonomy (biology)