Eumalacostraca
Encyclopedia
The Eumalacostraca are a subclass of crustacean
s, containing almost all living malacostraca
ns, about 40,000 described species. The remaining subclasses are the Phyllocarida
and possibly the Hoplocarida
or mantis shrimps.
Eumalacostracans have 19 segments (5 cephalic, 8 thoracic, 6 abdominal). The thoracic limbs are jointed and used for swimming or walking. The common ancestor is thought to have had a carapace
, and most living species possess one, but it has been lost in some subgroups.
The group as originally described by Karl Grobben
included the Stomatopoda (mantis shrimp), and some modern experts continue to use this definition. This article follows Martin and Davis in excluding them; they are placed in their own subclass, Hoplocarida
.
Subclass Eumalacostraca Grobben, 1892
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...
s, containing almost all living malacostraca
Malacostraca
Malacostraca is the largest of the six classes of crustaceans, containing over 25,000 extant species, divided among 16 orders. Its members display a greater diversity of body forms than any other class of animals, and include crabs, lobsters, shrimp, krill, woodlice, scuds , mantis shrimp and many...
ns, about 40,000 described species. The remaining subclasses are the Phyllocarida
Phyllocarida
Phyllocarida is a subclass of crustaceans, comprising the extant order Leptostraca and the extinct orders Hymenostraca and Archaeostraca....
and possibly the Hoplocarida
Hoplocarida
Hoplocarida is a subclass of crustaceans. The only extant members are the mantis shrimp , but two other orders existed in the Palaeozoic: Aeschronectida and Palaeostomatopoda....
or mantis shrimps.
Eumalacostracans have 19 segments (5 cephalic, 8 thoracic, 6 abdominal). The thoracic limbs are jointed and used for swimming or walking. The common ancestor is thought to have had a carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
, and most living species possess one, but it has been lost in some subgroups.
Classification
Martin and Davis present the following classification of living eumalacostracans into orders, to which extinct orders have been added, indicated by †.The group as originally described by Karl Grobben
Karl Grobben
Karl Grobben was an Austrian biologist. He graduated from, and later worked at, the University of Vienna, chiefly on molluscs and crustaceans...
included the Stomatopoda (mantis shrimp), and some modern experts continue to use this definition. This article follows Martin and Davis in excluding them; they are placed in their own subclass, Hoplocarida
Hoplocarida
Hoplocarida is a subclass of crustaceans. The only extant members are the mantis shrimp , but two other orders existed in the Palaeozoic: Aeschronectida and Palaeostomatopoda....
.
Subclass Eumalacostraca Grobben, 1892
- Superorder SyncaridaSyncaridaSyncarida is a superorder of crustaceans, comprising the two orders Anaspidacea and Bathynellacea. Fifty-nine genera are known, in six families:Anaspidacea Calman, 1904*Anaspididae Thomson, 1893*Koonungidae Sayce, 1908*Psammaspididae Schminke, 1974...
Packard, 1885- †Order Palaeocaridacea
- Order BathynellaceaBathynellaceaBathynellacea is an order of crustaceans which live interstitially in groundwater. Some species can tolerate low salt concentrations, and at least one African species is a thermophile, living in hot springs and tolerating temperatures up to . Bathynellaceans are minute, blind, worm-like animals...
Chappuis, 1915 - Order AnaspidaceaAnaspidaceaAnaspidacea is an order of crustaceans, comprising eleven genera in four families. Species in the family Anaspididae vary from being strict stygobionts to species living in lakes, streams and moorland pools, and are found only in Tasmania...
Calman, 1904 (including Stygocaridacea)
- Superorder PeracaridaPeracaridaThe superorder Peracarida is a large group of malacostracan crustaceans, having members in marine, freshwater, and terrestrial habitats. They are chiefly defined by the presence of a brood pouch, or marsupium, formed from thin flattened plates borne on the basalmost segments of the legs Other...
Calman, 1904- Order SpelaeogriphaceaSpelaeogriphaceaSpelaeogriphacea is an order of crustaceans that grow to no more than . Little is known about the ecology of the order.Only four species, all subterranean, have been described...
Gordon, 1957 - Order ThermosbaenaceaThermosbaenaceaThermosbaenacea is a group of crustaceans that live in thermal springs in fresh water, brackish water and anchialine habitats. They have occasionally been treated as a distinct superorder , but are generally considered to belong to the Peracarida...
Monod, 1927 - Order LophogastridaLophogastridaLophogastrida is an order of malacostracan crustaceans in the superorder Peracarida. They are shrimp-like animals that mostly inhabit the relatively deep pelagic waters of the oceans throughout the world....
Sars, 1870 - Order Mysida Haworth, 1825
- Order MictaceaMictaceaMictacea is the most recently established order of crustaceans, erected for five species of small shrimp-like animals of the deep sea and anchialine caves.-Description:...
Bowman, Garner, Hessler, Iliffe & Sanders, 1985 - Order AmphipodaAmphipodaAmphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
Latreille, 1816 - Order IsopodaIsopodaIsopods are an order of peracarid crustaceans, including familiar animals such as woodlice and pill bugs. The name Isopoda derives from the Greek roots and...
Latreille, 1817 (pillbugs, sowbugs, woodlice) - Order TanaidaceaTanaidaceaThe crustacean order Tanaidacea make up a minor group within the class Malacostraca. There are about 940 species in this order.-Description:...
Dana, 1849 - Order CumaceaCumaceaCumacea is an order of small marine crustaceans, occasionally called hooded shrimp. Their unique appearance and uniform body plan makes them easy to distinguish from other crustaceans.-Anatomy:...
Krøyer, 1846
- Order Spelaeogriphacea
- Superorder EucaridaEucaridaEucarida is a superorder of the Malacostraca, a class of the crustacean subphylum, comprising the decapods, krill and Amphionides. They are characterised by having the carapace fused to all thoracic segments, and by the possession of stalked eyes....
Calman, 1904- Order Euphausiacea Dana, 1852
- Order AmphionidaceaAmphionidesAmphionides reynaudii is the sole representative of the order Amphionidacea, and is a small planktonic crustacean found throughout the world's tropical oceans, mostly in shallow waters.-Description:...
Williamson, 1973 - Order DecapodaDecapodaThe decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
Latreille, 1802 (crabs, lobsters, shrimp)