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 Int ...
is that the first such name to be published is the senior homonym and is to be used (it is "
valid
Validity or Valid may refer to:
Science/mathematics/statistics:
* Validity (logic), a property of a logical argument
* Scientific:
** Internal validity, the validity of causal inferences within scientific studies, usually based on experiments
** ...
"); 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
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the ...
.
:*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
(ICN) specifies that the first published of two or more homonyms is to be used: a later homonym is "
illegitimate
Legitimacy, in traditional Western common law, is the status of a child born to parents who are legally married to each other, and of a child conceived before the parents obtain a legal divorce. Conversely, ''illegitimacy'', also known as ...
" and is not to be used unless
conserved (or sanctioned, in the case of fungi).
:Example: the later homonym ''
Myroxylon'' L.f. (1782), in the family
, is conserved against the earlier homonym ''Myroxylon'' J.R.Forst. & G.Forst. (1775) (now called ''
Xylosma'', 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) and a species of orchid (kingdom
Plantae
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
). 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 abbrevia ...
*
Isonym – in botany, an identical name based on the same type, but published later. Isonyms have no nomenclatural status (they are not
validly published
In botanical nomenclature, a validly published name is a name that meets the requirements in the ''International Code of Nomenclature for algae, fungi, and plants'' for valid publication. Valid publication of a name represents the minimum require ...
).
References
{{reflist, 33em
Botanical nomenclature
Zoological nomenclature
01
Taxonomy (biology)