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, and puddles, damp moss, or water-filled recesses (phytotelmata) of plants 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.
Poecilostomatoida are an suborder of copepods. Although it was previously considered a separate order, recent research showed it to be nested within the Cyclopoida
Ergasilidae is a widespread family of copepods and comprises many species. The type genus is Ergasilus. With a few doubtful exceptions all ergasilids are parasitic on fishes.
Monstrilloida is an order of copepods with a cosmopolitan distribution in the world's oceans. The order contains a single family, Monstrillidae. The name of the first ever described genus Monstrilla is derived from latin, meaning "tiny monster", because the lack of usual diagnostic features of copepods puzzled early taxonomists.
Clausidium vancouverense, the red copepod, is a symbiont of the ghost shrimp Neotrypaea californiensis. It is one of six species in the genus Clausidium and is found with its host in the Pacific Ocean from Alaska to Baja California.
Ectinosomatidae is a family of the Harpacticoida, a huge group of crustaceans belonging to the subclass Copepoda. Like most of their relatives, they are usually benthic inhabitants of marine environments. Ectinosomatidae commonly inhabit sediment and fragments of dead corals or glass sponges, and occasionally algae and bryozoans, in the deep oceans. In the epifaunal species, the first leg pair is often modified to allow the animals a better grip on the substrate.
Oncaea venusta is a species of copepod with a cosmopolitan distribution, but lacking from the Arctic Ocean. Females are 1.1–1.3 mm (0.043–0.051 in) long, while males are only 0.8–1.0 mm (0.031–0.039 in) long. The front of the head is unusually wide, and the body is brightly coloured, usually yellow–orange, but sometimes red. O. venusta feeds on a variety of zooplankton and phytoplankton.
Clausidiidae is a family of parasitic copepods of the suborder Poecilostomatoida, containing the following genera:
Neotrypaea californiensis, the Bay ghost shrimp, is a species of ghost shrimp that lives on the Pacific coast of North America. It is a pale animal which grows to a length of 11.5 cm (4.5 in). One claw is bigger than the other, especially in males, and the enlarged claw is thought to have a function in mating. N. californiensis is a deposit feeder that lives in extensive burrow systems, and is responsible for high rates of bioturbation. It adversely affects oyster farms, and its numbers are controlled in some places by the application of pesticides. It carries out an important role in the ecosystem, and is used by fishermen as bait.
Lernaeocera branchialis, sometimes called cod worm, is a parasite of marine fish, found mainly in the North Atlantic. It is a marine copepod which starts life as a small pelagic crustacean larva. It is among the largest of copepods, ranging in size from 2 to 3 millimetres when it matures as a copepodid larva to more than 40 mm as a sessile adult.
Pennella is a genus of large copepods which are common parasites of large pelagic fishes. They begin their life cycle as a series of free-swimming planktonic larvae. The females metamorphose into a parasitic stage when they attach to a host and enter into its skin. The males are free swimming. Due to their large size and mesoparasitic life history there have been a number of studies of Pennella, the members of which are among the largest of the parasitic Copepoda. All species are found as adults buried into the flesh of marine bony fish, except for a single species, Pennella balaenopterae which can be found in the muscles and blubber of cetaceans and occasionally other marine mammals, and is the largest species of copepod.
Pennella balaenopterae is a large ectoparasitic copepod specialising in parasitising marine mammals. It is the largest member of the genus Pennella, the other species of which are parasites of larger marine fish.
Crustaceans form a large, diverse arthropod taxon which includes such animals as crabs, lobsters, crayfish, shrimps, prawns, krill, woodlice, and barnacles. The crustacean group can be treated as a subphylum under the clade Mandibulata; because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the clade Pancrustacea other than hexapods. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
Tracheliastes polycolpus is a copepod ectoparasite of a number of freshwater fish in Western Europe, including Leuciscus burdigalensis, the beaked dace. The parasite attaches itself to the fins of the host, and lives on the mucus and epithelial cells of the host.
Lepeophtheirus pectoralis is a species of parasitic copepod from the northeast Atlantic Ocean, and the type species of the genus Lepeophtheirus. It is a parasite of flatfish, with the European flounder, the plaice, and the dab as the most frequent hosts. It feeds on the mucus, skin, and blood of the fish, with egg-producing females infecting the pectoral and pelvic fins of the host, while immature individuals and males are found on the rest of the body.
Clausidium dissimile is a species of copepod that has been found along the Atlantic and Gulf Coasts from Massachusetts to Florida. They are found on the bodies of mud shrimp of the family Callianassidae, or from water collected from mud shrimp burrows.
Longipedia is a genus of marine copepods of the family Longipediidae, order Canuelloida.
Mesocyclops longisetus is a species of freshwater copepod in the family Cyclopidae. Two subspecies are accepted, Mesocyclops longisetus curvatus Dussart, 1987, and Mesocyclops longisetus longisetus. It has a neotropical distribution.
Bryocyclops is a genus of freshwater-dwelling cyclopoid copepods. The epithet Bryo- for Bryophyta (Mosses) refers to the fact that the first few species were described from mosses.
Callichirus major sensu lato is a monophyletic species complex of ghost shrimp in the infraorder Axiidea, found in flat sandy beaches across the Pan-American coastline.
