Last updated
Subspecies LifeDomainKingdomPhylumClassOrderFamilyGenusSpecies
The hierarchy of biological classification's eight major taxonomic ranks. Intermediate minor rankings are not shown.
Ceylon paradise flycatcher (female) - Sri Lanka - 02.jpg
Ceylon paradise flycatcher (Terpsiphone paradisi ceylonensis), an Indian paradise flycatcher subspecies native to Sri Lanka
Leopard africa.jpg
African leopard (Panthera pardus pardus), the nominotypical (nominate) leopard subspecies native to Africa [1]
Sumatran Tiger 4 (6964676168).jpg
Sunda Island tiger (P. tigris sondaica), a tiger subspecies native to the Sunda islands [1]

In biological classification, the term subspecies refers to one of two or more populations of a species living in different subdivisions of the species' range and varying from one another by morphological characteristics. [2] [3] A single subspecies cannot be recognized independently: a species is either recognized as having no subspecies at all or at least two, including any that are extinct. The term may be abbreviated to subsp. or ssp. The plural is the same as the singular: subspecies.


In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks.

A taxonomist decides whether to recognize a subspecies. A common criterion for recognizing two distinct populations as subspecies rather than full species is the ability of them to interbreed without a fitness penalty [ citation needed ]. In the wild, subspecies do not interbreed due to geographic isolation or sexual selection. The differences between subspecies are usually less distinct than the differences between species.


The scientific name of a species is a binomial or binomen, and comprises two Latin words, the first denoting the genus and the second denoting the species. [4] The scientific name of a subspecies is formed slightly differently in the different nomenclature codes. In zoology, under the International Code of Zoological Nomenclature (ICZN), the scientific name of a subspecies is termed a trinomen, and comprises three words, namely the binomen followed by the name of the subspecies. [5] For example, the binomen for the leopard is Panthera pardus. The trinomen Panthera pardus fusca denotes a subspecies, the Indian leopard. [1]

In botany, subspecies is one of many ranks below that of species, such as variety, subvariety, form, and subform. To identify the rank, the subspecific name must be preceded by "subspecies" (which can be abbreviated to "subsp." or "ssp."), as in Schoenoplectus californicus subsp. tatora. [6]

In bacteriology, the only rank below species that is regulated explicitly by the code of nomenclature is subspecies, but infrasubspecific taxa are extremely important in bacteriology; Appendix 10 of the code lays out some recommendations that are intended to encourage uniformity in describing such taxa. Names published before 1992 in the rank of variety are taken to be names of subspecies [7] (see International Code of Nomenclature of Prokaryotes ). As in botany, subspecies is conventionally abbreviated as "subsp.", and is used in the scientific name: Bacillus subtilis subsp. spizizenii. [8]

Nominotypical subspecies and subspecies autonyms

In zoological nomenclature, when a species is split into subspecies, the originally described population is retained as the "nominotypical subspecies" [9] or "nominate subspecies", which repeats the same name as the species. For example, Motacilla alba alba (often abbreviated M. a. alba) is the nominotypical subspecies of the white wagtail (Motacilla alba).

The subspecies name that repeats the species name is referred to in botanical nomenclature as the subspecies "autonym", and the subspecific taxon as the "autonymous subspecies". [10]

Doubtful cases

When zoologists disagree over whether a certain population is a subspecies or a full species, the species name may be written in parentheses. Thus Larus (argentatus) smithsonianus means the American herring gull; the notation within the parentheses means that some consider it a subspecies of a larger herring gull species and therefore call it Larus argentatus smithsonianus, while others consider it a full species and therefore call it Larus smithsonianus (and the user of the notation is not taking a position).[ citation needed ]


A subspecies is a taxonomic rank below species – the only such rank recognized in the zoological code, [11] and one of three main ranks below species in the botanical code. [10] When geographically separate populations of a species exhibit recognizable phenotypic differences, biologists may identify these as separate subspecies; a subspecies is a recognized local variant of a species. [12] Botanists and mycologists have the choice of ranks lower than subspecies, such as variety (varietas) or form (forma), to recognize smaller differences between populations. [10]

Monotypic and polytypic species

The Indian rhinoceros (Rhinoceros unicornis) is a monotypic species One horn Rhino in Kaziranga national park.jpg
The Indian rhinoceros (Rhinoceros unicornis) is a monotypic species

In biological terms, rather than in relation to nomenclature, a polytypic species has two or more genetically and phenotypically divergent subspecies, races, or more generally speaking, populations that differ from each other so that a separate description is warranted. [13] These distinct groups do not interbreed as they are isolated from another, but they can interbreed and have fertile offspring, e.g. in captivity. These subspecies, races, or populations, are usually described and named by zoologists, botanists and microbiologists.[ citation needed ]

In a monotypic species, all populations exhibit the same genetic and phenotypical characteristics. Monotypic species can occur in several ways:[ citation needed ]

See also

Related Research Articles

Binomial nomenclature System of identifying species of organisms using a two-part name

Binomial nomenclature, also called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name or a scientific name; more informally it is also called a Latin name.

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 International Commission on Zoological Nomenclature. The rules principally regulate:

In biology, a tribe is a taxonomic rank above genus, but below family and subfamily. It is sometimes subdivided into subtribes. By convention, all taxonomic ranks above genus are capitalized, including both tribe and subtribe.

In botanical nomenclature, variety is a taxonomic rank below that of species and subspecies, but above that of form. As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies rank should be used to recognize geographic distinctiveness, whereas the variety rank is appropriate if the taxon is seen throughout the geographic range of the species.

In biology, trinomial nomenclature refers to names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany.

Within biological taxonomy, a honey bee race would be an informal rank in the taxonomic hierarchy, below the level of subspecies. It has been used as a higher rank than strain, with several strains making up one race. Therefore, a strain is a lower-level taxonomic rank used at the intraspecific level within a race of a subspecies. Strains are often seen as inherently artificial concepts, more usually within biology as characterized by a specific intent for genetic isolation, however, within beekeeping circles, strain is more likely to be used to describe very minor differences throughout the same subspecies, such as the color ranges of A. m. carnica from brown to grey. Within A. m. ligustica there are two races, the darker leather brown northern Italian bee from the Ligurian Alps region which was discovered to be resistant to acarine in the 1900s, while the other Italian bee race, from regions near Bologna and further south, was highly susceptible to acarine and within this race there are two color strains, the traditional Italian yellow and a rarer all-golden color.

Type species

In zoological nomenclature, a type species is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). A similar concept is used for suprageneric groups and called a type genus.

In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term original combination or protonym is used in the same way in zoology. Bacteriology uses a similar term, basonym, spelled without an i.


In evolutionary ecology, an ecotype, sometimes called ecospecies, describes a genetically distinct geographic variety, population or race within a species, which is genotypically adapted to specific environmental conditions.

Botanical name Scientific name for a plant, alga or fungus

A botanical name is a formal scientific name conforming to the International Code of Nomenclature for algae, fungi, and plants (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the International Code of Nomenclature for Cultivated Plants (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups ."

Race (biology) Informal rank in the taxonomic hierarchy, below the level of subspecies

In biological taxonomy, race is an informal rank in the taxonomic hierarchy, below the level of subspecies. It has been used as a higher rank than strain, with several strains making up one race. Various definitions exist. Races may be genetically distinct populations of individuals within the same species, or they may be defined in other ways, e.g. geographically, or physiologically. Genetic isolation between races is not complete, but genetic differences may have accumulated that are not (yet) sufficient to separate species. The term is recognized by some, but not governed by any of the formal codes of biological nomenclature.

In botany, an infraspecific name is the scientific name for any taxon below the rank of species, i.e. an infraspecific taxon. The scientific names of botanical taxa are regulated by the International Code of Nomenclature for algae, fungi, and plants (ICN). This specifies a 'three part name' for infraspecific taxa, plus a 'connecting term' to indicate the rank of the name. An example of such a name is Astrophytum myriostigma subvar. glabrum, the name of a subvariety of the species Astrophytum myriostigma.

In zoological nomenclature, the specific name is the second part within the scientific name of a species. The first part of the name of a species is the name of the genus or the generic name. The rules and regulations governing the giving of a new species name are explained in the article species description.

In zoological nomenclature, a trinomen, trinominal name, or ternary name, refers to the name of a subspecies. For example: "Gorilla gorilla gorilla" for the western lowland gorilla. Also, "Bison bison bison" for the plains bison.

In botanical nomenclature, author citation is the way of citing the person or group of people who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Nomenclature for algae, fungi, and plants (ICN). In cases where a species is no longer in its original generic placement, both the authority for the original genus placement and that for the new combination are given.

In zoology, the word "form" or forma is a strictly informal term that is sometimes used to describe organisms. Under the International Code of Zoological Nomenclature the term has no standing. In other words, although form names are Latin, and are sometimes wrongly appended to a binomial name, in a zoological context, forms have no taxonomic significance at all.

Taxonomic rank Level in a taxonomic hierarchy

In biological classification, taxonomic rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.

In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined.

In zoology, the Principle of Coordination is one of the guiding principles of the International Code of Zoological Nomenclature.

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 abbreviations are used with or without a stop.



  1. 1 2 3 Kitchener, A. C.; Breitenmoser-Würsten, C.; Eizirik, E.; Gentry, A.; Werdelin, L.; Wilting, A.; Yamaguchi, N.; Abramov, A. V.; Christiansen, P.; Driscoll, C.; Duckworth, J. W.; Johnson, W.; Luo, S.-J.; Meijaard, E.; O’Donoghue, P.; Sanderson, J.; Seymour, K.; Bruford, M.; Groves, C.; Hoffmann, M.; Nowell, K.; Timmons, Z.; Tobe, S. (2017). "A revised taxonomy of the Felidae: The final report of the Cat Classification Task Force of the IUCN Cat Specialist Group". Cat News. Special Issue 11: 66−69. hdl:10088/32616.
  2. Mayr, E. (1982). "Of what use are subspecies?". The Auk. 99 (3): 593−595.
  3. Monroe, B. L. (1982). "A modern concept of the subspecies". The Auk. 99 (3): 608−609.
  4. Linné, C. (1735). Systema naturae, sive, Regna tria naturae systematice proposita per classes, ordines, genera, & species. Lugduni Batavorum: Theodor Haak.
  5. Ride, W. D. L.; Corliss, J. O., eds. (1999). International Code of Zoological Nomenclature: Adopted by the International Union of Biological Sciences (PDF) (Fourth ed.). London: The International Trust for Zoological Nomenclature. ISBN   0853010064.
  6. James, Mallet. "Subspecies, semispecies, superspecies" (PDF). Retrieved 27 April 2018.
  7. "Chapter 3: Rules of Nomenclature with Recommendations". National Center for Biotechnology Information. Retrieved January 17, 2013.
  8. Parker, Charles T.; Tindall, Brian J.; Garrity, George M. (20 November 2015) [2008]. "International Code of Nomenclature of Prokaryotes (2008 Revision)". International Journal of Systematic and Evolutionary Microbiology (ICSP Matters ed.). 69. "Names of Subspecies: Rule 13a". doi: 10.1099/ijsem.0.000778 . PMID   26596770. Full text available from PDF link at this page; direct URL to PDF is auto-generated and expires.
  9. International Code of Zoological Nomenclature, Art. 47
  10. 1 2 3 McNeill, J.; Barrie, F. R.; Buck, W. R.; Demoulin, V.; Greuter, W.; Hawksworth, D. L.; Herendeen, P. S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G. F.; Wiersema, J. H.; Turland, N. J. (2012). International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011. Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN   978-3-87429-425-6.
  11. Rosenberg, Gary; et al. (eds.). "ICZN Glossary". International Code of Zoological Nomenclature. International Commission on Zoological Nomenclature.
  12. Russell, Peter J.; Hertz, Paul E.; McMillan, Beverly (2011). "21: Speciation". Biology: The Dynamic Science. Brooks/Cole California. p. 456. ISBN   978-1133418849.
  13. Mayr, E. (1970). Populations, Species, and Evolution: An Abridgment of Animal Species and Evolution . Harvard University Press.