Harpacticoida is an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

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

s, in the

subphylum In zoological nomenclature, a subphylum is a taxonomic rank below the rank of phylum. The taxonomic rank of " subdivision" in fungi and plant taxonomy is equivalent to "subphylum" in zoological taxonomy. Some plant taxonomists have also used th ...

Crustacea 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 c ...

. This order comprises 463

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

and about 3,000

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

; its members are

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning " ...

s found throughout the world in the marine environment (most families) and in

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does incl ...

(essentially the

Ameiridae Ameiridae is a family of crustaceans belonging to the order Harpacticoida 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 throu ...

, Parastenocarididae and the

Canthocamptidae Canthocamptidae is a family of copepods. Most of the 700 species are confined to fresh water, although there are also marine species. It contains the following genera: *'' Afrocamptus'' Chappuis, 1932 *'' Antarctobiotus'' Chappuis, 1930 *'' Antr ...

). A few of them are

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...

ic or live in association with other organisms. Harpacticoida represents the second-largest

meiofauna Meiobenthos, also called meiofauna, are small benthic invertebrates that live in both marine and fresh water environments. The term ''meiofauna'' loosely defines a group of organisms by their size, larger than microfauna but smaller than macrof ...

l group in

marine sediment Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor. These particles have their origins in soil and rocks and have been transported from the land to the sea, mai ...

s, after

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...

s. In Arctic and Antarctic seas, Harpacticoida are common inhabitants of

sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's o ...

. The name Harpacticoida comes from the Greek noun ''harpacticon'' (rapacious predator) and the suffix ''-oid'' (akin to) and means ''reminiscent of a predator'' . Harpacticoids are distinguished from other copepods by the presence of only a very short pair of first antennae. The second pair of antennae are biramous, and the major joint within the body is located between the fourth and fifth body segments. They typically have a wide

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

, and often have a somewhat worm-like body.

Families

53 families are currently recognised in the Harpacticoida: *

Adenopleurellidae Adenopleurellidae is a family of crustaceans belonging to the order Harpacticoida 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 fou ...

* Aegisthidae *

Ancorabolidae Ancorabolidae is a family of copepods belonging to the order Harpacticoida 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 thro ...

* Arenopontiidae *

Argestidae Argestidae is a family of copepods belonging to the order Harpacticoida 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 through ...

Balaenophilidae Balaenophilidae is a family of copepods belonging to the order Harpacticoida 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 th ...

Chappuisiidae ''Chappuisius'' is a genus of crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipo ...

Cletodidae Cletodidae is a family of copepods belonging to the order Harpacticoida 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 through ...

Cletopsyllidae Cletopsyllidae is a family of crustaceans belonging to the order Harpacticoida 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 ...

Cristacoxidae Cristacoxidae is a family of crustaceans belonging to the order Harpacticoida 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 t ...

Cylindropsyllidae Cylindropsyllidae is a family of copepods belonging to the order Harpacticoida 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 ...

Dactylopusiidae Dactylopusiidae is a family of copepods belonging to the order Harpacticoida 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 th ...

Darcythompsoniidae 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 direc ...

Ectinosomatidae Ectinosomatidae is a family (biology), family of the Harpacticoida, a huge group of crustaceans belonging to the Class (biology), subclass Copepoda. Like most of their relatives, they are usually benthic inhabitants of marine environments. Ectino ...

* Hamondiidae * Harpacticidae * Idyanthidae * Laophontidae *

Laophontopsidae Laophontopsidae is a family of copepods belonging to the order Harpacticoida 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 th ...

* Latiremidae * Leptastacidae * Leptopontiidae *

Louriniidae Louriniidae is a family of crustaceans belonging to the order Harpacticoida 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 thr ...

Metidae Metidae is a family of copepods belonging to the order Harpacticoida. Genera: * '' Ilyopsilla'' * '' Lauberia'' * '' Laubieria'' Soyer, 1966 * ''Metis Metis or Métis may refer to: Ethnic groups * Métis, recognized Indigenous communities in ...

Miraciidae Miraciidae is a family (biology), family of copepods in the family Miraciidae. Subdivisions The World Register of Marine Species lists the following genera as accepted within Miraciidae, subdivided into three subfamilies. References

...

* Nannopodidae * Neobradyidae *

Normanellidae Normanellidae is a family of copepods belonging to the order Harpacticoida 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 thro ...

Novocriniidae Novocriniidae is a family of crustaceans belonging to the order Harpacticoida 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 t ...

* Orthopsyllidae * Parameiropsidae * Paramesochridae * Parastenheliidae * Parastenocarididae * Peltidiidae * Phyllognathopodidae * Pontostratiotidae * Porcellidiidae * Protolatiremidae *

Pseudotachidiidae Pseudotachidiidae is a family of crustaceans belonging to the order Harpacticoida 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 fou ...

Rhizothricidae Rhizotrichidae is a family of crustaceans belonging to the order Harpacticoida 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 ...

* Rometidae * Rotundiclipeidae *

Superornatiremidae Superornatiremidae is a family of crustaceans belonging to the order Harpacticoida 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 fo ...

* Tachidiidae * Tegastidae * Tetragonicipitidae *

Thalestridae Thalestridae is a family of copepods belonging to the order Harpacticoida 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 throu ...

* Thompsonulidae * Tisbidae * Zosimeidae

References

External links

Harpacticoida, Guide to the marine zooplankton of south eastern AustraliaTasmanian Aquaculture and Fisheries Institute
* {{Taxonbar, from=Q146286 Crustacean orders