Euphausiacea


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Related to Euphausiacea: Decapoda, Cirripedia, Branchiopoda, Caridea

Euphausiacea

[yü‚fȯ·zē′ās·ē·ə]
(invertebrate zoology)
An order of planktonic malacostracans in the class Crustacea possessing photophores which emit a brilliant blue-green light.

Euphausiacea

 

an order of higher crustaceans. The body varies in length from 5 to 96 mm. Externally the animals resemble shrimp of the order Decapoda, differing from them in having gills that are not covered by a thoracic shield and that are located on the bases of the thoracic extremities. The biramous thoracic extremities are used only for swimming. The eyes are stalk-shaped; there are photophores on the eye stalks, as well as on the bases of several pairs of thoracic limbs and on the first four abdominal segments. The Euphausiacea are dioecious. Eggs are laid in the water. The larva leaves the egg during the nauplius stage, after which several more developmental stages follow; the cycle from egg to adult is completed in three or four months.

The order embraces approximately 90 known species, which are widely distributed in the world ocean, especially in subtropical and tropical regions. The animals reproduce in large numbers in some seas, where they are the source of food for various marine mammals and fishes. In the waters of Antarctica the accumulation of some species of whale is related to the mass reproduction of krill, including one member of the Euphausiacea, Euphasia superba. In the Barents Sea, the mass-reproducing species Thysanoessa raschii is a food source for herring, Eurasian perch, Atlantic cod, and other commercial fishes.

REFERENCES

Zhizn’ zhivotnykh, vol. 2. Moscow, 1968.
Dogel’, V. A. Zoologiia bespozvonochnykh, 6th ed. Moscow, 1975.

A. V. IVANOV

References in periodicals archive ?
Chaetognatha, Thaliacea, Euphausiacea and Pelagic Polychaeta in the Colombian Pacific Ocean, during two periods in 1996 (La Nina) and two periods in 1997 (El Nino).
De acuerdo al IIR es de manifiesto predominio entre los crustaceos especies de la orden Euphausiacea, siguiendoles en presencia las larvas zoeas y otros tipos de pequenos crustaceos que llegan a ser incluso predominantes al finalizar el ano.
Euphausiacea y Teleosteos fueron importantes en la dieta de reclutas y adultos (Fig.
Other crustacean groups recorded with high relative abundance were Decapoda (4.7%), Cladocera (3.7%), Mysidacea (2.7%), and Euphausiacea (2.0%).
Population structure of daytime surface swarms of Nyctiphanes simplex (Crustacea: Euphausiacea) in the Gulf of California, Mexico.
Cross-shelf circulation, zonation and maintenance mechanisms of Nyctiphanes capensis and Euphausia hanseni (Euphausiacea) in the northern Benguela upwelling system.
Note that "krill 1" (Order Euphausiacea) is as close to two of the molluscs as it is to the other crustaceans (Order Decapoda).
15.10 0.01 Euphausiacea 11.00 < 0.01 Decapoda Galatheidae Pleuroncodes planipes 1937.00 0.84 Osteichthyes Clupeiformes Clupeidae 3206.00 1.39 Etrumeus teres 19681.00 8.52 Opisthonema libertate 4985.00 2.16 Sardinops caeruleus 36492.00 15.79 Gadiformes Merlucciidae Merluccius productus 16619.00 7.19 Exocoetidae Exocoetus spp.
Small hakes feed daily on small Euphausiacea (Nictiphanes couchi).
Die Eucarida sind nicht monophyletisch - Ommatidienstruktur deutet auf nahere Verwandtschaft von Euphausiacea. Syncarida und Peracarida (Crustacea).
Se identificaron los siguientes grupos del holozooplancton: radiolarios (Clase Radiolaria), foraminiferos (Orden Foraminifera), sifonoforos (Orden Siphonophora), medusas (Clase Hydrozoa excepto sifonoforos), clenoforos (Phylum Ctenophora), tecosornados (Orden Thecosomata), gimnosomados (Orden Gymnosomata), heteropodos (Suborden Heteropoda), poliquetos (Clase Polychaeta), cladoceros (Orden Cladocera), ostracodos (Subclase Ostracoda), copepodos (Subclase Copepoda), misidaceos (Orden Mysidacea), anfipodos (Orden Amphipoda), eufausidos (Orden Euphausiacea), decapodos pelagicos (Orden Decapoda), quetognatos (Phyllum Chaetognata), apendicularias (Orden Appendicularia) y tunicados (Clase Thaliacea).