Copepod
Guides
Acanthocyclops
Acanthocyclops is a genus of freshwater copepod crustaceans in the family Cyclopidae, originally described by Friedrich Kiefer in 1927 as a subgenus of Cyclops. Species within this genus inhabit diverse aquatic environments ranging from temporary ponds to large permanent lakes. The genus has been validated through ecological studies demonstrating distinct habitat preferences and life history strategies among closely related species.
Acartia
Acartia is a genus of marine calanoid copepods comprising the majority of species in the family Acartiidae. They are small, planktonic crustaceans found primarily in temperate coastal and estuarine waters worldwide. The genus includes ecologically important species such as A. tonsa, which is among the most abundant and well-studied estuarine copepods globally. Acartia species serve as key intermediaries in aquatic food webs and are increasingly used as model organisms for studying coastal plankton dynamics, thermal ecology, and phylogeographic patterns.
Calanidae
Calanidae is the largest family of calanoid copepods, containing ecologically dominant genera including Calanus, potentially the most abundant metazoan genus on Earth. Members inhabit marine environments from surface waters to depths exceeding 400 m, with distributions spanning polar, temperate, and tropical oceans. The family exhibits significant vertical stratification and seasonal abundance patterns, with some species performing ontogenetic vertical migrations for overwintering. Calanidae species play critical roles in marine food webs as primary consumers and prey for fish and higher trophic levels.
Centropagidae
Centropagidae is a family of calanoid copepods comprising 14 genera and over 130 species. Members occupy diverse aquatic habitats including marine coastal waters, freshwater lakes, and saline lakes across the Southern Hemisphere, with notable concentrations in Australia, southern South America, subantarctic islands, and Antarctica. The family exhibits significant habitat diversity: marine genera include Centropages, Dussartopages, and Gladioferens; freshwater genera include Boeckella, Calamoecia, and Hemiboeckella. The genus Boeckella poppei represents the only terrestrial/freshwater invertebrate reported from all three main Antarctic biogeographic regions (subantarctic islands, maritime Antarctic, and continental Antarctic).
Cyclopoida
Cyclopoid Copepods
Cyclopoida is an order of small crustaceans within the class Copepoda, comprising approximately 30 families. Members are primarily planktonic, inhabiting both marine and freshwater environments, and are distinguished by morphological features including antennae shorter than the head and thorax combined. The order exhibits metamorphic larval development with embryos carried in paired or single sacs attached to the first abdominal somite. Molecular phylogenetic studies have reclassified the former order Poecilostomatoida as a lineage nested within Cyclopoida.
Diacyclops
Diacyclops is a genus of cyclopoid copepods in the family Cyclopidae containing over 120 described species. Species occupy diverse aquatic habitats including freshwater lakes, wetlands, rivers, and groundwater systems. Some species are planktonic while others are benthic or stygobiontic. The genus shows broad salinity tolerance, with at least one species thriving in brackish conditions up to 5 ppt. Diacyclops species serve as prey for fish and are sensitive indicators of environmental contaminants.
Diacyclops thomasi
Diacyclops thomasi is a cyclopoid copepod species in the family Cyclopidae, first described by Forbes in 1882. The species exhibits a distinctive life cycle involving summer diapause with whole-body encystment at the copepodid IV stage. During encystment, the organism undergoes profound metabolic depression and ultrastructural reorganization of its digestive tract, including transformation of midgut epithelial cells and accumulation of lipid-rich lacunae.
Diaptomidae
Diaptomidae is a family of freshwater pelagic copepods comprising approximately 50 genera. Members are the most widespread copepods in lentic inland waters of the Palearctic region. The family contains two subfamilies: Diaptominae and Paradiaptominae, with the latter consisting almost exclusively of African taxa. Diaptomids exhibit high species richness in tropical and Mediterranean regions, with numerous endemic species.
Epischura
Epischura is a genus of freshwater calanoid copepods in the family Temoridae. The genus contains approximately 11 recognized species, including the well-studied Epischura lacustris of North American lakes and the endemic Epischura baikalensis of Lake Baikal. Species within this genus exhibit diverse feeding strategies ranging from omnivory to predation, with documented consumption of both phytoplankton and zooplankton prey. The genus has been proposed as paraphyletic with respect to Heterocope, with suggestions to transfer the Siberian species E. baikalensis and E. chankensis to the resurrected genus Epischurella.
Epischura lacustris
Epischura lacustris is a predatory calanoid copepod in the family Temoridae. It inhabits freshwater lakes across northeastern North America, including all five Great Lakes. The species exhibits size-selective predation on small zooplankton, particularly Bosmina longirostris, and has been observed to consume both phytoplankton and animal prey. It can be distinguished from other Great Lakes calanoids by three stout caudal setae on each caudal ramus and a noticeably bent urosome in mature specimens.
Harpacticoida
Harpacticoid Copepods
Harpacticoida is an order of benthic copepods comprising approximately 463 genera and 3,000 species. Members are predominantly marine but include freshwater families (Ameiridae, Parastenocarididae, Canthocamptidae). They represent the second-largest meiofaunal group in marine sediments after nematodes and are also common in Arctic and Antarctic sea ice. A few species are planktonic or live in association with other organisms.
Lernaea
anchor worms
Lernaea is a genus of parasitic copepod crustaceans commonly called anchor worms, exclusively parasitic on freshwater fishes. Females burrow into fish flesh and transform into unsegmented, wormlike forms with egg sacs visible externally, while males are free-swimming and short-lived. The genus is widely distributed globally and causes significant disease in aquaculture and wild fish populations. Multiple species exist, with Lernaea cyprinacea being the most studied and economically important.
Lernaea cyprinacea
anchor worm, fish louse
Lernaea cyprinacea is a parasitic copepod commonly known as the anchor worm, a significant pest in freshwater aquaculture worldwide. Native to Eurasia, it has been introduced to multiple continents including North America and South America. The species exhibits sexual dimorphism with females becoming permanently attached to fish hosts while males are free-living and short-lived. It causes substantial economic damage through direct parasitism, reduced fish growth, and secondary infections.
Lernaeidae
anchorworms
Lernaeidae is a family of parasitic copepods in the order Cyclopoida, commonly known as anchorworms. The family contains approximately 131 species across 20 genera, all of which are obligate ectoparasites of freshwater fishes. Species in this family are characterized by elongated bodies, often with anchor-like holdfast structures used for attachment to host tissues. The most widely distributed and economically significant species is Lernaea cyprinacea, which has been introduced globally and causes substantial damage in aquaculture systems.
Lernaeopodidae
Lernaeopodidae is a family of parasitic copepods in the order Siphonostomatoida. Females are typically large and fleshy, attaching permanently to fish hosts using a chitinous plug called the bulla. Males are smaller and cling to females using their antennae. Members parasitize both marine and freshwater fishes, with some species causing significant problems in aquaculture.
Oncaea
Oncaea is a genus of small marine copepods in the family Oncaeidae, order Poecilostomatoida. The genus includes bioluminescent species that exhibit internal (non-secreted) bioluminescence, a distinctive trait among copepods. Members occur in marine environments from tropical to polar regions, including the Arctic Ocean, Antarctic waters, and the Mediterranean Sea. Some species have been documented feeding on chaetognaths and other crustaceans, though feeding mechanisms appear complex and variable.
Oncaeidae
Oncaeidae is a family of microcopepods characterized by small body size, high abundance, and high species diversity across all ocean basins. The family was established by Giesbrecht in 1893 and comprises approximately 115 described species across seven genera. Members occur from surface waters to bathypelagic depths, exhibiting a life strategy fundamentally different from most other pelagic microcopepod families. Their ecological role in marine ecosystems remains incompletely understood despite their numerical importance.
Salmincola
Salmincola is a genus of freshwater parasitic copepods in the family Lernaeopodidae. These ectoparasites are common on salmonid fishes throughout the Northern Hemisphere. The genus exhibits substantial geographic variation in infection rates across water bodies, and current taxonomic definitions based on decades-old morphological descriptions may obscure cryptic diversity. Species in this genus are considered pests by fisheries management agencies due to their impact on host fish populations.
Salmincola californiensis
gill lice, gill maggot, salmon gill maggot
Salmincola californiensis is a freshwater parasitic copepod in the family Lernaeopodidae that infests the gills and branchial cavities of salmonid fishes, particularly species of Oncorhynchus. Native to the Pacific Rim and now established in introduced ranges including Japan and Colorado, this parasite has become a significant concern for fisheries management and salmonid conservation. Recent research has documented a previously unrecognized naupliar stage and demonstrated strong temperature-dependence in egg development and copepodid survival, with implications for disease management under climate change scenarios.
Sapphirina
Sea Sapphires
Sapphirina is a genus of marine planktonic copepods in the family Sapphirinidae, commonly known as sea sapphires. Males exhibit striking iridescent structural coloration ranging from gold to deep blue, produced by multilayered guanine crystal plates beneath the dorsal cuticle. Females are translucent and lack this coloration. The genus comprises specialized predators of pelagic tunicates (salps), with some species exhibiting a complex life history involving both parasitic and predatory phases.
Sapphirinidae
Sapphirinidae is a family of copepods in the order Cyclopoida, established by Thorell in 1859. The family includes three genera: Copilia, Sapphirina, and Vettoria. Members exhibit striking sexual dimorphism in coloration, with males displaying bright, iridescent colors while females remain transparent. They are found in marine environments.
Siphonostomatoida
Siphon-mouth Copepods
Siphonostomatoida is an order of copepods distinguished by siphon-like mandibles and a frontal filament used for host attachment. The order comprises 40 recognized families, with approximately 75% of all fish-parasitizing copepods belonging to this group. Most species are marine symbionts, though a few inhabit freshwater environments. Members exhibit diverse host associations, with 17 families parasitizing vertebrates (primarily fishes) and 23 families associated with invertebrates.
copepodparasitemarinefish-parasitesymbiontcrustaceanectoparasiteSiphonostomatoidabiodiversitySouthern-AfricaJapanBrazilsponge-associatecoral-associatedevelopmental-stageschalimusfrontal-filamentsiphon-mandibleAsterocheridaeLernaeopodidaePennellidaeHatschekiidaeSphyriidaeNotodelphyidaeBotryllophilidaeTemoridae
Temoridae is a family of calanoid copepods established by Giesbrecht in 1893. The family includes seven genera: Epischura, Epischurella, Eurytemora, Ganchosia, Heterocope, Lahmeyeria, and Temora. Members inhabit diverse aquatic environments ranging from freshwater lakes to brackish estuaries and marine coastal waters. The genus Eurytemora has been extensively studied due to its species complex containing cryptic species with significant genetic and morphological heterogeneity.