Caridea

Distinguished from Dendrobranchiata (prawns) by three key characters: (1) lamellar versus branching gill structure, (2) second abdominal segment overlapping both first and third segments (versus overlapping only the third), and (3) typically two pairs of chelae versus three. Distinguished from Stenopodidea by the absence of greatly enlarged third pereiopods. Distinguished from Axiidea (mud shrimp) by body form and gill structure. Brooding of eggs on pleopods versus release into water column separates Caridea from Dendrobranchiata.

Body plan conforms to a generalized natantian (swimming) decapod form with elongated, laterally compressed abdomen. Size ranges from a few millimeters to over 300 mm in length. Carapace covers and protects the cephalothorax and gills; water circulation through gills is driven by mouthpart action. One pair of stalked eyes is typically present, though sometimes covered by the carapace. Second abdominal segment overlaps both first and third segments (distinctive from Dendrobranchiata). Typically possess two pairs of chelae (claws), compared to three in dendrobranchiates. Foregut contains multiple patterns of ossicles accommodating diverse feeding modes.

Occupies every category of aquatic habitat. Majority of species are marine, occurring from intertidal zones to depths of 5,000 meters. Approximately one-quarter of described species inhabit freshwater, including nearly all Atyidae and Palaemoninae (Palaemonidae). Freshwater species occur on all continents except Antarctica. Marine species range from tropical to polar regions. Benthic species dominate, though some are pelagic or associated with specific substrates including coral rubble, anemones, and tunicates.

Global distribution in freshwater and marine environments. Freshwater species present on all continents except Antarctica. Marine species occur from tropical to polar latitudes and from surface waters to hadal depths.

Most species are omnivorous. Specialized feeding modes include: filter feeding using setose legs as sieves; algae scraping from hard substrates; predation using snapping claws (Alpheus) to generate shock waves; and consumption of parasites and necrotic tissue from host fish (cleaner shrimp).

• fish - cleaning symbiosisCleaner shrimp remove parasites and necrotic tissue from reef fish
• sea anemones - symbiosisSome species live among anemone tentacles or use anemone tissue for protection (blanket-hermit crabs in related groups)
• tunicates - commensalismSome small species inhabit tunicate cavities
• bopyrid isopods - parasitismCarideans frequently host bopyrid parasites

Eggs are brooded on female pleopods rather than released into water. Embryonic development completes all naupliar stages within the egg; larvae eclose as zoeae. Zoeal stages feed on phytoplankton; number of zoeal stages varies from 2 to 13 depending on species. Post-zoeal stage (decapodid) resembles miniature adult but retains some larval characters. Final metamorphosis produces post-larval juvenile with full adult characteristics.

Most adults are benthic, living primarily on the sea floor. Some species exhibit specialized behaviors: snapping shrimp generate cavitation bubbles to stun prey; cleaner shrimp establish stations on reefs where fish present themselves for parasite removal; some deep-sea species exhibit filter-feeding behavior previously unknown in carideans.

Important components of aquatic food webs as both predators and prey. Cleaner shrimp provide ecosystem services by maintaining health of reef fish populations. Serve as food for fish, seabirds, and other predators. Some species are significant bioturbators in benthic environments.

Several species support commercial fisheries, notably Pandalus borealis (pink shrimp) and Crangon crangon (brown shrimp). Wild capture fisheries produced approximately 430,000 tonnes in 2010, representing about 13% of global wild shrimp capture. Some species are cultured, though carideans contribute minimally to global aquaculture compared to penaeid shrimp. Popular in marine aquarium trade, particularly cleaner shrimp. Subject of extensive research on viral diseases including White Spot Syndrome Virus.

• DendrobranchiataOften called prawns; distinguished by branching gills, different abdominal segmentation, three pairs of chelae, and release of eggs into water column rather than brooding
• StenopodideaContains boxer shrimp; distinguished by greatly enlarged third pereiopods
• AxiideaContains mud shrimp; not true shrimp despite common names; distinct body plan and gill structure

• commercially important
• freshwater
• marine
• deep sea
• cleaner shrimp
• omnivorous

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Zookeys | Blog - Part 26
• marine science | Blog - Part 3
• Decapoda | Blog
• Caridea and Amphionides
• Protection of Caridea Against White Spot Syndrome Virus
• Description of Alpheopsis gorei sp. nov., a mesophotic alpheid shrimp from the western Atlantic (Decapoda: Caridea)
• Seleção de habitat e natureza polimórfica em populações do camarão Hippolyte obliquimanus Dana, 1852 (Decapoda; Caridea)
• Sequence comparison of the mitochondrial genomes of Plesionika species (Caridea: Pandalidae), gene rearrangement and phylogenetic relationships of Caridea