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.^[1] 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).^[1]

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",^[2] names without an accompanying description (nomina nuda, singular nomen nudum), such as the subgeneric name Micronectomys proposed for the Nicaraguan rice rat,^[3] names proposed with a rank below that of subspecies (infrasubspecific names), such as Sorex isodon princeps montanus for a form of the taiga shrew,^[4] 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.^[2]

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.^[5] The botanical equivalent of zoology's term "valid name" is correct name.

References

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.

This zoology–related article is a stub. You can help Wikipedia by adding missing information.

• v
• t
• e