Platycopiidae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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

s. Until the description of ''Nanocopia'' in 1988, it contained the single genus ''Platycopia''. It now contains four genera, three of which are

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

; the exception is ''Platycopia'', with 8 species.

Systematics

The family Platycopiidae was erected by

Georg Ossian Sars Prof Georg Ossian Sars H FRSE (20 April 1837 – 9 April 1927) was a Norwegian marine and freshwater biologist. Life Georg Ossian Sars was born on 20 April 1837 in Kinn, Norway (now part of Flora), the son of Pastor Michael Sars and Maren S ...

when he described the new species ''P. perplexa'', and included it in the order Calanoida. In 1948, Karl Georg Herman Lang erected a new suborder, Progymnoplea, for the family, and in 1985, Audun Fosshagen & Thomas Iliffe created the order Platycopioida to contain the Platycopiidae, initially placed alongside Calanoida in the superorder

Gymnoplea Calanoida is an order of copepods, a group of arthropods commonly found as zooplankton. The order includes around 46 families with about 1800 species of both marine and freshwater copepods between them. Description Calanoids can be disting ...

. Most recently, Huys & Boxshall inferred that Platycopiidae was the earliest branching copepod lineage, making it the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to all other copepods; they therefore raised Progymnoplea to the

rank Rank is the relative position, value, worth, complexity, power, importance, authority, level, etc. of a person or object within a ranking, such as: Level or position in a hierarchical organization * Academic rank * Diplomatic rank * Hierarchy * ...

of infraclass, to accommodate Platycopioida alone, with all other copepods being placed in the

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

. Members of the Platycopiidae have a primitive form, thought to be similar to the

most recent common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...

of all copepods. Few synapormorphies have been found to unite the family, but they include the presence of a second dorsal

seta In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. ...

(hair) on particular segments of the legs. They share with calanoid copepods the possession of Von Vaupel Klein's organ, a sensory organ near the base of the first swimming leg.

Members

''Antrisocopia prehensilis'' Fosshagen, 1985 is a critically endangered species from a

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

anchialine An anchialine system (, from Greek ''ankhialos'', "near the sea") is a landlocked body of water with a subterranean connection to the ocean. Depending on its formation, these systems can exist in one of two primary forms: pools or caves. The primary ...

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

Bermuda ) , anthem = "God Save the King" , song_type = National song , song = " Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , e ...

, known from only five mature specimens. ''Nanocopia minuta'' Fosshagen, 1988 is a critically endangered species from the same anchialine cave as ''Antrisocopia'', and is known from only two specimens. ''Sarsicopia polaris'' Martínez Arbizu, 1997 was collected in 1993 from a depth of in the

Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...

. ''Platycopia'' comprises eight species, distributed in the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

, the eastern seaboard of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, the

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

Mauritania Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber: ''Agawej'' or ''Cengit''; Pulaar: ''Moritani''; Wolof: ''Gànnaar''; Soninke:), officially the Islamic Republic of Mauritania ( ar, الجمهورية الإسلامية ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. The first species to be described was ''P. perplexa'', named by

in 1911.

References

{{Taxonbar, from=Q13656302 Copepods Crustacean families