Subspecies

Subspecies (commonly abbreviated "subsp." or "ssp.") in biological classification is either a taxonomic rank subordinate to species, or a taxonomic unit in that rank (plural: subspecies). A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one. (However, all but one subspecies may be extinct, as in Homo sapiens sapiens.)