Subspecies
In biological classification, subspecies (pl.: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed.[2][3] Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are").
This article is about the biological term. For the film series, see Subspecies (film series).
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 even if some male offspring may be sterile.[4] 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.
Criteria[edit]
A subspecies is a taxonomic rank below species – the only such rank recognized in the zoological code,[13] and one of three main ranks below species in the botanical code.[12] 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.[14] Botanists and mycologists have the choice of ranks lower than subspecies, such as variety (varietas) or form (forma), to recognize smaller differences between populations.[12]
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.[15] 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.
In a monotypic species, all populations exhibit the same genetic and phenotypical characteristics. Monotypic species can occur in several ways:
