subfamily

Subfamily is a taxonomic rank used in the classification of organisms. It sits below the family and above the tribe, serving to group together genera that share a more recent common ancestry than other genera within the same family. In plants, the rank similarly lies between family and tribe, aiding the organization of large families into smaller, related segments.

In zoological nomenclature, subfamily names typically end with the suffix -inae, while the corresponding family ends with -idae. For example, the family Hominidae includes the subfamily Homininae, which contains humans and related great apes, and the subfamily Ponginae, which includes orangutans. The family Canidae includes subfamily Caninae. In plants, subfamilies generally end with -oideae, such as Solanoideae within Solanaceae, or Faboideae within Fabaceae.

The rank is used to reflect evolutionary relationships within a family and to organize diversity in a way that highlights shared characteristics and lineage. However, not all taxonomic groups employ subfamilies, and some classifications prefer unranked clades or other intermediate ranks. The acceptance and definition of subfamilies can vary among taxonomic schools and over time as new phylogenetic information becomes available.

Etymology traces subfamily to the Latin sub- meaning under and familia meaning family. The term thus denotes a subdivision within a family, intended to capture a distinct subset of related organisms within a broader evolutionary lineage.