sousespèce

A subspecies is a taxonomic rank below species used for populations within a species that are distinct in morphology, genetics, or geography but are capable of interbreeding with other populations of the same species. Subspecies reflect patterns of population structure and historical isolation, rather than complete separation.

Differences that define subspecies are often regional and can be subtle, such as variations in coloration, size, or skull shape, and increasingly supported by genetic data. Subspecies are typically confined to particular geographic areas or habitats where gene flow with other populations is limited by barriers like mountains, deserts, or rivers. Not all species have recognized subspecies; in some cases, variation is continuous or not sufficiently distinct to warrant the rank.

In zoology, subspecies are named with trinomial nomenclature: Genus species subspecies (for example Panthera tigris altaica, the Siberian tiger). In botany, the rank is also used, usually written as Genus species subsp. name, with varieties and forms occasionally serving similar purposes.

The concept is sometimes debated within taxonomy. Different authorities may disagree on whether a population warrants subspecies status, and advances in genetics can lead to reclassifications that elevate subspecies to full species or merge them with other populations. Subspecies designations can have conservation implications by highlighting unique regional lineages and guiding protection priorities. In French usage, the term is sous-espèce, the equivalent concept in taxonomic practice.