Taxonomy
Krill belong to the large arthropod subphylum, the Crustacea. The most familiar and largest group of crustaceans, the class Malacostraca, includes the superorder Eucarida comprising the three orders, Euphausiacea (krill), Decapoda (shrimp, lobsters, crabs), and the planktonic Amphionides.
The order Euphasiacea comprises two families. The more abundant Euphausiidae contains ten different genera with a total of 85 species. Of these, the genus Euphausia is the largest, with 31 species. The lesser known family, the Bentheuphausiidae, has only one species, Bentheuphausia amblyops, a bathypelagic krill living in deep waters below 1,000 metres (3,300 ft). It is considered the most primitive extant krill species.
Well-known species of the Euphausiidae of commercial krill fisheries include Antarctic krill (Euphausia superba), Pacific krill (Euphausia pacifica) and Northern krill (Meganyctiphanes norvegica).
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