''Acartia clausi'' is a species of marine

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) ...

belonging to the family

Acartiidae Acartiidae is a family of calanoid copepods distinguishable by the rostral margin not being extended. They are epipelagic, plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are u ...

. This species was previously thought to have a worldwide distribution but recent research has restricted its range to coastal regions of the north-eastern Atlantic Ocean as far north as Iceland, the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

and the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

, with specimens from other regions assigned to different species. At just over 1 mm in length, this is a generally larger animal than its closest congeners. It can also be distinguished by the row of large spines at the rear margin of the body segment known as the metasome.

References

''Acartia clausi'' at World of Copepods
Calanoida Crustaceans described in 1889 {{copepod-stub