caridean

Caridea, commonly called caridean shrimp, is an infraorder of decapod crustaceans within the suborder Pleocyemata of the order Decapoda. The group covers a large and diverse set of shrimp-like species found in a wide range of habitats, including marine, estuarine, and some freshwater environments. In traditional classifications, carideans are distinguished from the related infraorder Dendrobranchiata, which includes many of the larger prawns.

Taxonomy and characteristics. Carideans are generally small to medium-sized, with a laterally compressed body and a well-developed first pair of thoracic legs adapted for walking. A defining reproductive feature in Pleocyemata, including carideans, is that females brood eggs on their pleopods until hatching (ovigerous females). The infraorder contains many families and a broad array of forms, from commensal cleaners to predatory shrimps, and includes both widely familiar aquarium species and commercially important taxa.

Distribution and ecology. Carideans have a near-global distribution, occupying shallow coastal waters, reefs, mangroves, continental shelves, and, in some lineages, freshwater systems. They play key ecological roles as scavengers, detritivores, grazers, and predators. Freshwater lineages are represented by several genera in families such as Atyidae, which contribute to biodiversity in streams and rivers.

Importance and notes. Carideans support substantial fisheries and aquaculture, particularly some penaeid and other commercially harvested groups. They are also prominent in the aquarium trade, with many genera such as Caridina and Neocaridina being popular among hobbyists. Taxonomic arrangements within Caridea have shifted with molecular studies, but the group remains a primary reference point for discussions of shrimp-like decapods.