''Oithona'' is a

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

genus found in marine, brackish, fresh water environments. ''Oithona'' has been described as the most ubiquitous and abundant

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

in the world's oceans. It was first described by Baird in 1843 using the species ''Oithona plumifera'' as taxon type. The following species are recognized: * ''Oithona aculeata'' Farran, 1913 * ''Oithona alvarezi'' Lindberg, 1955 * ''Oithona amazonica'' Burckhardt, 1913 * ''Oithona aruensis'' Früchtl, 1923 * ''Oithona atlantica'' Farran, 1908 * ''Oithona attenuata'' Farran, 1913 * ''Oithona australis'' Nishida, 1986 * ''Oithona bjornbergae'' Ferrari F.D. & Bowman, 1980 * ''Oithona bowmani'' Rocha C.E.F., 1986 * ''Oithona brevicornis'' Giesbrecht, 1891 * ''Oithona colcarva'' Bowman, 1975 * ''Oithona cruralis'' Nishida, Tanaka & Omori, 1977 * ''Oithona davisae'' Ferrari F.D. & Orsi, 1984 * ''Oithona decipiens'' Farran, 1913 * ''Oithona dissimilis'' Lindberg, 1940 * ''Oithona erythrops'' Brady, 1915 * ''Oithona fallax'' Farran, 1913 * ''Oithona farrani'' (Brady, 1915) * ''Oithona flemingeri'' (Ferrari & Bowman, 1980) * ''Oithona fonsecae'' Ferrari & Bowman, 1980 * ''Oithona fragilis'' Nishida, 1979 * ''Oithona frigida'' Giesbrecht, 1902 * ''Oithona gessneri'' Kiefer, 1954 * ''Oithona hamata'' Rosendorn, 1917 * ''Oithona hebes'' Giesbrecht, 1891 * ''Oithona horai'' Sewell, 1934 * ''Oithona linearis'' Giesbrecht, 1891 * ''Oithona longispina'' Nishida, Tanaka & Omori, 1977 * ''Oithona minuta'' Scott T., 1894 * ''Oithona minuta'' Krichagin, 1877 * ''Oithona nana'' Giesbrecht, 1893 * ''Oithona nishidai'' McKinnon, 2000 * ''Oithona oswaldocruzi'' Oliveira, 1945 * ''Oithona pacifica'' (Nishida, 1985) * ''Oithona parvula'' (Farran, 1908) * ''Oithona plumifera'' Baird, 1843 * ''Oithona pseudofrigida'' Rosendorn, 1917 * ''Oithona pseudovivida'' Shuvalov, 1980 * ''Oithona pulla'' (Farran, 1913) * ''Oithona robertsoni'' McKinnon, 2000 * ''Oithona robusta'' Giesbrecht, 1891 * ''Oithona rostralis'' Nishida, Tanaka & Omori, 1977 * ''Oithona setigera'' (Dana, 1849) * ''Oithona similis'' Claus, 1866 * ''Oithona simplex'' Farran, 1913 * ''Oithona splendens'' Baird, 1843 * ''Oithona tenuis'' Rosendorn, 1917 * ''Oithona vivida'' Farran, 1913 * ''Oithona wellershausi'' Ferrari F.D., 1982 * ''Oithona abbreviata'' (Dana, 1849) (taxon inquirendum, listed as "Unbestimmbare Species" by Giesbrecht, 1892) * ''Oithona alia'' (Kiefer, 1935) accepted as ''Oithona rigida'' Giesbrecht, 1896 accepted as ''Dioithona rigida'' (Giesbrecht, 1896) (synonym according to Nishida, 1985) * ''Oithona canhanhae'' Oliveira, 1945 accepted as ''Oithona hebes'' Giesbrecht, 1891 (placed in synonymy by da Rocha, 1986) * ''Oithona challengeri'' Brady, 1883 accepted as ''Oithona setigera'' (Dana, 1849) (listed as synonym by Nishida, 1985) * ''Oithona helgolandica'' (Claus, 1863) accepted as ''Oithona similis'' Claus, 1866 * ''Oithona neotropica'' Herbst, 1967 accepted as ''Oithona oswaldocruzi'' Oliveira, 1945 (placed in synonymy by da Rocha, 1986) * ''Oithona oculata'' Farran, 1913 accepted as ''Dioithona oculata'' (Farran, 1913) (synonym ) * ''Oithona oligohalina'' Fonseca & Björnberg T.K.S., 1976 accepted as ''Oithona oswaldocruzi'' Oliveira, 1945 (placed in synonymy by da Rocha, 1986) * ''Oithona oraemaris'' Oliveira, 1946 accepted as ''Oithona hebes'' Giesbrecht, 1891 (placed in synonymy by da Rocha, 1986) * ''Oithona ovalis'' Herbst, 1955 accepted as ''Oithona hebes'' Giesbrecht, 1891 (placed in synonymy by da Rocha, 1986) * ''Oithona ovata'' Lindberg, 1950 accepted as ''Oithona attenuata'' Farran, 1913 (synonymised by Nishida, 1985) * ''Oithona pelagica'' Farran, 1908 accepted as ''Oithona setigera'' (Dana, 1849) (listed as synonym by Nishida, 1985) * ''Oithona plumosa'' Lindberg, 1947 accepted as ''Oithona nana'' Giesbrecht, 1893 (synonymised by Nishida, 1985) * ''Oithona pygmaea'' Boeck, 1865 accepted as ''Oithona similis'' Claus, 1866 (listed as probable synonym by Giesbrecht, 1892) * ''Oithona rigida'' Giesbrecht, 1896 accepted as ''Dioithona rigida'' (Giesbrecht, 1896) * ''Oithona sapucaiae'' Oliveira, 1945 accepted as ''Oithona hebes'' Giesbrecht, 1891 (placed in synonymy by da Rocha, 1986) * ''Oithona scriba'' (Dana, 1849) accepted as ''Oithona plumifera'' Baird, 1843 (listed as synonym by Giesbrecht, 1892) * ''Oithona sinensis'' Burckhardt, 1912 accepted as ''Limnoithona sinensis'' (Burckhardt, 1913) * ''Oithona spinifrons'' Boeck, 1865 accepted as ''Oithona similis'' Claus, 1866 * ''Oithona spinirostris'' Claus, 1863 accepted as ''Oithona setigera'' (Dana, 1849) (listed as synonym by Nishida, 1985) * ''Oithona spinulosa'' Lindberg, 1950 accepted as ''Oithona brevicornis'' Giesbrecht, 1891 (synonym according to Nishida & Ferrari, 1983) * ''Oithona tropica'' Wolfenden, 1906 accepted as ''Oithona setigera'' (Dana, 1849) (listed as synonym by Nishida, 1985)

References

{{Taxonbar, from=Q6556536 Cyclopoida genera