Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic, some are benthic, a number of species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, puddles, damp moss, or water-filled recesses of plants (phytotelmata) such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators.
Harpacticoida is an order of copepods, in the subphylum Crustacea. This order comprises 463 genera and about 3,000 species; its members are benthic copepods found throughout the world in the marine environment and in fresh water. A few of them are planktonic or live in association with other organisms. Harpacticoida represents the second-largest meiofaunal group in marine sediments, after nematodes. In Arctic and Antarctic seas, Harpacticoida are common inhabitants of sea ice. The name Harpacticoida comes from the Greek noun harpacticon and the suffix -oid and means reminiscent of a predator.
Ceuthonectes is a genus of copepods in the family Canthocamptidae. It includes the Slovenian endemic species C. rouchi, which is listed as a vulnerable species on the IUCN Red List. Ceuthonectes contains the following species:
Elaphoidella is a genus of freshwater copepods in the family Canthocamptidae. It contains over 200 species, including three classified as vulnerable species by the IUCN – three endemic to Slovenia and one endemic to the United States. In total, the genus Elaphoidella contains the following species:
Ingolfiella is a genus of amphipod in the family Ingolfiellidae, containing the following species:
Leptocaris is a genus of copepods in the family Darcythompsoniidae. One species, the Mexican endemic L. stromatolicolus, is included on the IUCN Red List as a vulnerable species. The genus contains the following species:
Murunducaris is a genus of crustacean in family Parastenocarididae. It contains the following species:
Nitocrella is a genus of copepod. Although most other genera in the family Ameiridae are marine, species of Nitocrella are almost exclusively found in subterranean fresh water or brackish water. More than 80 species are included in the genus, including two which are listed as vulnerable species on the IUCN Red List:
Acantholochus is a genus of parasitic copepods belonging to the family Bomolochidae. Its members can only be distinguished from the closely related genus Hamaticolax by the absence of an accessory process on the claw of the maxillipeds.
Gelyella is a genus of freshwater copepods which are "surrounded by mystery". They live in groundwater in karstic areas of southern France and western Switzerland. The two species are the only members of the family Gelyellidae and, although previously placed in the order Harpacticoida, a new order, Gelyelloida, was erected for this family alone.
Tegastidae is a family of copepods, which are characterised by having laterally compressed bodies, a claw-like mandible in the nauplius stage, and by a modified male genital complex. 85 species have been described in 6 genera. Two species of Smacigastes are found at hydrothermal vents, while the remaining species are found in shallow water, associated with algae, bryozoans and cnidarians, such as corals.
Hamaticolax is a genus of parasitic copepods belonging to the family Bomolochidae. Its members can only be distinguished from the closely related genus Acantholochus by the presence of an accessory process on the claw of the maxillipeds. It includes the following species:
Darcythompsoniidae is a family of copepods, containing four genera. Members of the family have a very wide distribution throughout the tropics, where they live in rotting mangrove leaves. They lack egg sacs and are thought to lay their eggs directly into the leaf litter.
Tigriopus brevicornis is a coastal marine copepod. They are a dominant member of shallow supra tidal rock pools along the North Western European coastline. A broad range of studies have been carried out on this species, including: its ecology, physiology, phylogeography, metapopulation genetics, development and reproductive behaviour. T. brevicornis has also recently been used in ecotoxicology studies and has been trialled as a live feed for larvae in several aquaculture-based studies for the past 30 years.
Longipedia is a genus of marine copepods of the family Longipediidae, order Canuelloida.
Laophontidae is a family of copepods belonging to the order Harpacticoida.
Tachidiidae is a family of copepods belonging to the order Harpacticoida.
Ancorabolidae is a family of copepods belonging to the order Harpacticoida.
Cylindropsyllidae is a family of copepods belonging to the order Harpacticoida. It was first described by Sars in 1909
Paramesochridae is a family of copepods belonging to the order Harpacticoida.
