Harpacticoida
Encyclopedia
Harpacticoida is an order
of copepod
s, in the Subphylum
Crustacea
. This order comprises 463 genera
and about 3,000 species
. Members of it are benthic copepod
s found throughout the world in the marine environment (most families) and in fresh water
(essentially the Ameiridae, Parastenocarididae and the Canthocamptidae
). A few of them are plankton
ic or live in association with other organism
s. Harpacticoida represents the second-largest meiofaunal group in marine sediment
milieu, after nematode
s. In Arctic and Antarctic seas, Harpacticoida are common inhabitants of sea ice.
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
, and often have a somewhat worm-like body.
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, in the Subphylum
Subphylum
In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla...
Crustacea
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
. This order comprises 463 genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
and about 3,000 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. Members of it are benthic copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s found throughout the world in the marine environment (most families) and in fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
(essentially the Ameiridae, Parastenocarididae and the Canthocamptidae
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...
). A few of them are plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic or live in association with other organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s. Harpacticoida represents the second-largest meiofaunal group in marine sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
milieu, after nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s. In Arctic and Antarctic seas, Harpacticoida are common inhabitants of sea ice.
Harpacticoids are distinguished from other copepods by the presence of only a very short pair of first antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. 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
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, and often have a somewhat worm-like body.
Families
Sixty-seven families are currently recognised in the Harpacticoida:- Adenopleurellidae
- Aegisthidae
- Ameiridae
- Ancorabolidae
- Arenopontiidae
- Argestidae
- Balaenophilidae
- Cancrincolidae
- CanthocamptidaeCanthocamptidaeCanthocamptidae 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...
- Canuellidae
- Cerviniidae
- Chappuisiidae
- Cletodidae
- Cletopsyllidae
- Clytemnestridae
- Cristacoxidae
- Cylindropsyllidae
- Dactylopusiidae
- Danielsseniidae
- Darcythompsoniidae
- EctinosomatidaeEctinosomatidaeEctinosomatidae 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...
- Euterpinidae
- Hamondiidae
- Harpacticidae
- Heteropsyllidae
- Huntemanniidae
- Idyanthidae
- Ismardiidae
- Laophontidae
- Laophontopsidae
- Latiremidae
- Leptastacidae
- Leptopontiidae
- Longipediidae
- Louriniidae
- Metahuntemanniidae
- Metidae
- Miraciidae
- Neobradyidae
- Normanellidae
- Novocriniidae
- Orthopsyllidae
- Parameiropsidae
- Paramesochridae
- Paranannopidae
- Parastenheliidae
- Parastenocarididae
- Parastentheliidae
- Peltidiidae
- Phyllognathopodidae
- Porcellidiidae
- Protolatiremidae
- Pseudotachidiidae
- Rhizothricidae
- Rhynchothalestridae
- Rometidae
- Rotundiclipeidae
- Superornatiremidae
- Tachidiidae
- TegastidaeTegastidaeTegastidae 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. Around 60 species have been described in 6 genera...
- Tetragonicipitidae
- Thalestridae
- Thompsonulidae
- Tisbidae
- Zosimidae