suborder

Suborder is a taxonomic rank used in biological classification that sits below the rank of order and above infraorder or parvorder, depending on the group and system of classification. It groups together related families or genera within an order that share distinctive features or evolutionary history, without elevating them to a separate order.

The exact use of suborders varies among different lineages. In some groups, infraorders or other intermediate ranks are preferred or used in addition to suborders, and in others the rank is simply not employed. In botany, the term is also used to organize plants within an order, though the precise rank and naming conventions can differ from those in zoology. Because taxonomy adapts to new phylogenetic information, the status and contents of a suborder can change as classifications are revised.

Examples of suborders in well-known animal groups include Strepsirrhini and Haplorhini within the order Primates; Feliformia and Caniformia within the order Carnivora; and Nematocera and Brachycera within the order Diptera. Each of these suborders represents a line of descent with shared characteristics that justify grouping them together under a common suborder rather than placing them directly in separate orders.

Overall, suborder serves as a flexible, intermediate level in the hierarchical structure of classification, reflecting evolutionary relationships and providing a practical means to organize large groups of organisms without over-splitting into separate orders.