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.
Corophiida is an infraorder of amphipods that contains the two parvorders Caprellidira and Corophiidira.
The Hyperiidea are a suborder of amphipods, small aquatic crustaceans. Unlike the other suborders of Amphipoda, hyperiids are exclusively marine and do not occur in fresh water. Hyperiids are distinguished by their large eyes and planktonic habitat. Most species of hyperiids are parasites or predators of salps and jellyfish in the plankton, although Themisto gaudichaudii and a few relatives are free-swimming predators of copepods and other small planktonic animals.
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.
Phronima sedentaria is a species of amphipod crustaceans found in oceans at a depth of up to 1 km (0.6 mi). They are large in size relative to other members of the family Phronimidae. Individuals may be found inside barrel-like homes, created most commonly from the tunics of select species of tunicate, where they rear their young. P. sedentaria is known to employ multiple feeding strategies and other interesting behaviors, including daily vertical migration. The species is also known by the more common names “pram bug” and “barrel shrimp.”
Pallaseidae is a family of amphipod crustaceans endemic to Lake Baikal. Some species are also found in the Angara River which flows out of Lake Baikal, and one species is distributed throughout Northern Palearctic. The composition of the family is a subject of discussion, with different sources listing either 9 genera and 58 species, or 8 genera and 20 species. They are benthic, nectobenthic or epibiotic.
Abludomelita obtusata is a brown colored species of amphipod crustacean. It may grow up to 9 millimetres (0.35 in) long and lacks a rostrum. It lives in marine sediments of any grain size, but with a preference for a mud content of 10%–40%, around the coasts of the southern North Sea.
Amphilochus is a genus of crustaceans in the Amphipoda order, containing the following species:
Dikerogammarus is a genus of amphipod crustaceans, containing the following species:
Hyalella azteca is a widespread and abundant species complex of amphipod crustacean in North America. It reaches 3–8 mm (0.12–0.31 in) long, and is found in a range of fresh and brackish waters. It feeds on algae and diatoms and is a major food of waterfowl.
Alicellidae is a family of amphipod crustaceans, which live as scavengers in the deep sea, often in association with hydrothermal vents. The family includes the following genera:
Caprella kominatoensis is a species of skeleton shrimp in the genus Caprella. It was described in 1986 by Ichiro Takeuchi for specimens from Amatsu-Kominato, Chiba Prefecture, Japan, and is closely related to C. decipiens.
Martensia martensi is a species of amphipod crustacean, and the only species in the genus Martensia. It occurs in waters around Svalbard at depths of 37–95 metres (121–312 ft).
Sunamphitoe femorata is a species of amphipod crustacean in the family Ampithoidae. It is a herbivore and constructs a tubular nest-like home on a blade of the sporophyte of the giant kelp Macrocystis pyrifera. This home is made by rolling the sides of the blade together and securing them with silk. As the kelp blade grows, the nest is advanced down the blade towards the base, approximately keeping pace with the algal growth.
Brandtia is a monotypic genus of amphipod in the Acanthogammaridae family, containing the species Brandtia latissima. Like other members of the family, it is endemic to Lake Baikal. This omnivore is found at depths of 1–65 m (3–213 ft) among stones. It is up to 1.9 cm (0.75 in) long.
Luckia is a genus of amphipod crustaceans in the family Pontogeneiidae, with the sole species Luckia striki. It is found in hydrothermal vents in the Atlantic Ocean.
The clade Multicrustacea constitutes the largest superclass of crustaceans, containing approximately four-fifths of all described crustacean species, including crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods, mantis shrimp and others. The largest branch of multicrustacea is the class Malacostraca.
Pseudamphithoides incurvaria is a species of amphipod crustacean in the family Ampithoidae. It is native to shallow water in the tropical western Atlantic Ocean where it creates a home for itself from fragments of the algae on which it feeds. This seaweed contains certain chemicals that are distasteful and protect it from predatory fish.
Eurythenes is a genus of marine amphipods in the family Eurytheneidae.
