Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from 1 to 340 millimetres and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as Talitrus saltator and Arcitalitrus sylvaticus.
Gammaridea is one of the suborders of the order Amphipoda, comprising small, shrimp-like crustaceans. Until recently, in a traditional classification, it encompassed about 7,275 (92%) of the 7,900 species of amphipods described by then, in approximately 1,000 genera, divided among around 125 families. That concept of Gammaridea included almost all freshwater amphipods, while most of the members still were marine.
Pardaliscidae is a family of amphipods, whose members typically inhabit the deepest parts of ocean basins. It contains the following genera:
Talitridae is a family of amphipods. Terrestrial species are often referred to as landhoppers and beach dwellers are called sandhoppers or sand fleas. The name sand flea is misleading, though, because these talitrid amphipods are not siphonapterans, do not bite people, and are not limited to sandy beaches.
Lysianassidae is a family of marine amphipods, containing the following genera:
Gammaridae is a family of amphipods. In North America they are included among the folk taxonomic category of "scuds", and otherwise gammarids is usually used as a common name.
Gammarus roeselii is a species of freshwater amphipod native to Europe.
Bogidiella is a genus of crustacean in the family Bogidiellidae, containing the following species:
Ingolfiella is a genus of amphipod in the family Ingolfiellidae, containing the following species:
Niphargus is by far the largest genus of its family, the Niphargidae, and the largest of all freshwater amphipod genera.
Stygobromus is a genus of amphipod crustaceans that live in subterranean habitats. The majority of the listed species are endemic to North America, a smaller number of species are also known from Eurasia. Most of the North American species live in areas which were not covered by the Laurentide Ice Sheet, although a few species seem to have survived under the ice. A number of species are on the IUCN Red List as endangered species (EN) or vulnerable species (VU); one species, S. lucifugus, is extinct.
Niphargidae is a family of amphipod crustaceans. Its distribution is in western Eurasia, and its members mainly live in subterranean freshwaters habitats. It contains the following genera:
Hyalella is a genus of amphipods found in the Americas. They are mainly found in freshwater habitats.
Pomphorhynchidae is a family of parasitic worms from the order Echinorhynchida.
Dikerogammarus villosus, also known as the killer shrimp, is a species of amphipod crustacean native to the Ponto-Caspian region of eastern Europe, but which has become invasive across the western part of the continent. In the areas it has invaded, it lives in a wide range of habitats and will prey on many other animals. It is fast-growing, reaching sexual maturity in 4–8 weeks. As it has moved through Europe, it threatens other species and has already displaced both native amphipods and previous invaders.
Gammarus lacustris is an aquatic amphipod.
Platorchestia is a genus of sand flea, containing the following species:
Bogidiellidae is a family of amphipod crustaceans, containing the following genera:
Phoxocephalidae is a family of small, shrimp-like crustaceans in the suborder Gammaridea described by Georg Ossian Sars in 1891. It contains Cocoharpinia iliffei, a critically endangered species on the IUCN Red List.
Maera is a genus of amphipod crustacean in the family Maeridae, and was first described by William Elford Leach in 1814. The type taxon is Cancer (Gammarus) grossimanus Montagu, 1808, currently accepted as Maera grossimana.
