{{Short description|Properly constructed taxonomic name}} In zoological nomenclature, an '''available name''' is a scientific name for a taxon of animals that has been published after 1757 and conforming to all the mandatory provisions of the International Code of Zoological Nomenclature for the establishment of a zoological name. In contrast, an '''unavailable name''' is a name that does not conform to the rules of that code and that therefore is not available for use as a valid name for a taxon. Such a name does not fulfill the requirements in Articles 10 through 20 of the Code, or is excluded under Article 1.3.
==Requirements== For a name to be available, in addition to meeting certain criteria for publication, there are a number of general requirements it must fulfill: it must include a description or definition of the taxon, must use only the Latin alphabet, must be formulated within the binomial nomenclature framework, must be newly-proposed (not a redescription under the same name of a taxon previously made available) and originally used as a valid name rather than as a synonym, must not be for a hybrid or hypothetical taxon, must not be for a taxon below the rank of subspecies, etc. In some rare cases, a name which does not meet these requirements may nevertheless be available, for historical reasons, as the criteria for availability have become more stringent with successive Code editions.<ref name="iczn code">{{cite web|url=http://www.nhm.ac.uk/hosted-sites/iczn/code/ |title=ICZN article 12|accessdate=12 January 2024}}</ref> For example, a name originally appearing along with an illustration but no formal description may be an available name, but only if the illustration was published prior to 1930 (under Article 12.2.7).<ref name="iczn code" />
All available names must refer to a type, even if one was not provided at the time the name was first proposed. For species-level names, the type is usually a single specimen (a holotype, lectotype, or neotype); for generic-level names, the type is a single species; for family-level names, the type is a single genus. This hierarchical system of typification provides a concrete empirical anchor for all zoological names.
An available name is not necessarily a valid name, because an available name may be a homonym or subsequently be placed into synonymy. However, a valid name must always be an available one.
==Unavailable names== Unavailable names include names that have not been published, such as "''Oryzomys hypenemus''" and "Ubirajara jubatus",<ref name="Caetanotal2023">{{Cite journal|last1=Caetano|first1=João Marcus Vale|last2=Delcourt|first2=Rafael|last3=Ponciano|first3=Luiza Corral Martins de Oliveira|name-list-style=amp|date=March 2023|title=A taxon with no name: 'Ubirajara jubatus' (Saurischia: Compsognathidae) is an unavailable name and has no nomenclatural relevance|journal=Zootaxa|volume=5254 |issue=3 |pages=443–446 |doi=10.11646/zootaxa.5254.3.10|doi-access=free|pmid=37044710 }}</ref> names without an accompanying description (''nomina nuda'', singular ''nomen nudum''), such as the subgeneric name ''Micronectomys'' proposed for the Nicaraguan rice rat,<ref>Hershkovitz, 1970, pp. 789, 791</ref> names proposed with a rank below that of subspecies (infrasubspecific names), such as ''Sorex isodon princeps montanus'' for a form of the taiga shrew,<ref>Hutterer & Zaitsev, 2004, p. 89</ref> and various other categories.
Despite the frequent confusion caused by common sense, an unavailable name is not necessarily a ''nomen nudum''. A good exemplification of this is the case of the unavailable dinosaur name "Ubirajara jubatus", which was assumed by common sense to be a ''nomen nudum'' before a detailed analysis of its nomenclatural status.<ref name="Caetanotal2023">{{Cite journal|last1=Caetano|first1=João Marcus Vale|last2=Delcourt|first2=Rafael|last3=Ponciano|first3=Luiza Corral Martins de Oliveira|name-list-style=amp|date=March 2023|title=A taxon with no name: 'Ubirajara jubatus' (Saurischia: Compsognathidae) is an unavailable name and has no nomenclatural relevance|journal=Zootaxa|volume=5254 |issue=3 |pages=443–446 |doi=10.11646/zootaxa.5254.3.10|doi-access=free|pmid=37044710 }}</ref>
==Contrast to botany== Under the International Code of Nomenclature for algae, fungi, and plants, this term is not used. In botany, the corresponding term is validly published name.<ref>{{cite book|url=http://www.iapt-taxon.org/nomen/main.php?page=glo|author1=McNeill, J. |author2=Barrie, F.R. |author3=Buck, W.R. |author4=Demoulin, V. |author5=Greuter, W. |author6=Hawksworth, D.L. |author7=Herendeen, P.S. |author8=Knapp, S. |author9=Marhold, K. |author10=Prado, J. |author11=Reine, W.F.P.h.V. |author12=Smith, G.F. |author13=Wiersema, J.H. |author14=Turland, N.J. |year=2012|title=International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011: Glossary|volume=Regnum Vegetabile 154|publisher=A.R.G. Gantner Verlag KG|isbn=978-3-87429-425-6}}</ref> The botanical equivalent of zoology's term "valid name" is correct name.
==References== {{reflist}}
==Bibliography== *Hershkovitz, P. 1970. Supplementary notes on Neotropical ''Oryzomys dimidiatus'' and ''Oryzomys hammondi'' (Cricetinae). Journal of Mammalogy 51(4): 789-794. *Hutterer, R. & Zaitsev, M.V. 2004. Cases of homonymy in some Palaearctic and Nearctic taxa of the genus ''Sorex'' L. (Mammalia: Soricidae). Mammal Study 29:89-91. *International Commission for Zoological Nomenclature. 1999. International Code of Zoological Nomenclature, 4th edition. London: The International Trust for Zoological Nomenclature. Available online at https://web.archive.org/web/20090524144249/http://www.iczn.org/iczn/index.jsp. Accessed September 27, 2009.
Category:Zoological nomenclature
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