Subgenus

Subgenus is a rank in biological taxonomy that sits below genus and above species. It is used to group closely related species within a genus that share particular features or evolutionary lineage. The rank is not universally employed; many genera are described without subdividing into subgenera, and different taxonomic groups may prefer other intermediate ranks.

In zoological nomenclature, the subgenus is formal and widely used in some groups. The standard format places the subgenus in parentheses after the genus, as in Genus (Subgenus) species, with the subgenus often abbreviated subg. The subgenus name is part of the cited name only in this context. A commonly cited illustration is Panthera (Panthera) leo, used to denote the lion within a subgeneric framework, though many sources also refer simply to Panthera leo.

In botanical nomenclature, subgenus operates similarly as an optional rank between genus and species. The name may appear as Genus subgenus species or Genus subg. Subgenus epithet, depending on the publication and taxonomic practice. Subgenera in plants help organize large, diverse genera into inferred lineages, reflecting phylogeny or morphology.

The designation of subgenera is governed by the respective codes of nomenclature: the ICZN for animals and the ICN (International Code of Nomenclature for algae, fungi, and plants) for plants. Subgeneric names must be validly published and follow the codes’ rules for rank, publication, and citation. Overall, the subgenus provides a flexible tool for clarifying relationships within large genera while remaining optional and subject to taxonomic judgment.