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.
Liljeborgiidae is a family of amphipods, containing the following genera:
Phliantidae is a family of isopod-like amphipod crustaceans chiefly from the southern hemisphere.
Oedicerotidae is a family of amphipods. It comprises the following genera:
Lysianassidae is a family of marine amphipods, containing the following genera:
Orchestia is a genus of amphipods in the family Talitridae, containing the following species:
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.
Talorchestia is a genus of amphipod of the family Talitridae, containing the following species:
Iphimedia is a genus of amphipods which belongs to the family Iphimediidae in the arthropod group Amphipoda. It is the only genus of the family to have species which live in tropical waters. All other genera of the family are only found in cold or deep oceans.
Urothoe is a genus of very small marine amphipod crustaceans in the family Urothoidae. Members of the genus are found worldwide.
Pontogeneiidae is a family of amphipod crustaceans, containing the following genera:
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:
Photidae is a family of amphipod crustaceans, containing the following genera:
Corophiidira is a parvorder of marine amphipod crustaceans in the infraorder Corophiida. In a previous classification, this taxon was treated as an infraorder and was then itself called Corophiida.
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.
Cochinorchestia is a genus of amphipod belonging to the family Talitridae.
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.
