Amphipod
Guides
Americorchestia
beach hoppers
Americorchestia is a genus of beach hoppers (amphipods) in the family Talitridae, established by Bousfield in 1991. The genus contains five described species, including the common Atlantic sandhopper (A. longicornis) and the northern big-eyed sandhopper (A. megalophthalma). These amphipods inhabit coastal environments and are characterized by their jumping locomotion.
Americorchestia longicornis
Common Atlantic sandhopper
Americorchestia longicornis, the common Atlantic sandhopper, is a beach-dwelling amphipod in the family Talitridae. It inhabits sandy coastal environments along the Atlantic seaboard, where it functions as a detritivore and scavenger. The species is distinguished from similar beach hoppers by its elongated antennae, as reflected in its specific epithet.
Amphiporeia
Amphiporeia is a genus of gammaridean amphipods in the family Bathyporeiidae, comprising at least three described species: A. gigantea, A. lawrenciana, and A. virginiana. These small crustaceans are characteristic inhabitants of sandy marine and estuarine substrates along the Atlantic coast of North America, where they exhibit specialized burrowing behavior and tidal swimming activity. The genus is notable for pronounced sexual segregation within the sediment, seasonal population fluctuations, and reproductive strategies involving multiple broods per year. Species within Amphiporeia function as important components of benthic food webs, serving as both detritivores and prey for demersal fish.
Anisogammaridae
Anisogammaridae is a family of small benthic amphipod crustaceans endemic to the northern Pacific Rim. The family includes freshwater, estuarine, and marine species distributed across the Japanese Archipelago, Korean Peninsula, Chinese mainland, and Pacific coast of North America. Members exhibit diverse life history strategies including annual winter-breeding cycles in temperate freshwater habitats and bivoltine patterns in estuarine environments. The family is notable for containing the most diverse group of Japanese freshwater amphipods (genus Jesogammarus) and species of conservation concern due to restricted ranges and habitat vulnerability.
Bathyporeiidae
Bathyporeiidae is a family of amphipod crustaceans containing two genera: Amphiporeia and Bathyporeia. These small, laterally compressed marine invertebrates are primarily known from shallow coastal waters of northern Europe. The family was formally established by d'Udekem d'Acoz in 2011.
Calliopiidae
Calliopiidae is a family of hyperbenthic amphipods distributed across the North Atlantic and North Pacific oceans. Members inhabit diverse marine environments including subtidal waters, hydrothermal vents, and the hyperbenthic zone immediately above the seafloor. The family includes the newly described genus Bathya from deep-sea hydrothermal vents and Calliopius species associated with macroalgae.
Caprella verrucosa
Caprella verrucosa is a marine amphipod species in the family Caprellidae, commonly known as skeleton shrimp. The species was described by Boeck in 1871. It is found in temperate Asian waters, with confirmed records from the South Korean part of the Yellow Sea. Like other caprellids, it exhibits a reduced body plan with elongated pereiopods adapted for clinging to substrates in marine environments.
Caprellidae
Skeleton Shrimp, Ghost Shrimp
Caprellidae is a family of marine amphipods known as skeleton shrimps, characterized by their slender, threadlike bodies that provide camouflage among seaweed, hydroids, and bryozoans. They exhibit extreme sexual dimorphism, with males typically much larger than females. The family contains 88 genera across three subfamilies and is distributed worldwide in marine environments from intertidal zones to deep sea depths. Some species have been documented as invasive, spreading through biofouling on aquaculture equipment.
Crangonyx
cave amphipods, spring amphipods
Crangonyx is a genus of freshwater amphipod crustaceans in the family Crangonyctidae. Species inhabit diverse aquatic environments including surface waters (marshes, swamps, lakes, rivers) and subterranean habitats (caves, springs, groundwater systems). The genus includes both native and highly invasive species, with some taxa exhibiting troglobitic adaptations such as reduced eyes and elongated appendages. Several species have been introduced outside their native ranges, notably Crangonyx pseudogracilis and C. floridanus in Europe and Asia, where they interact competitively and predatorily with native amphipods.
Crangonyx gracilis
Northern Lake Crangonyctid
Crangonyx gracilis is a small freshwater amphipod in the family Crangonyctidae, commonly known as the northern lake crangonyctid. It inhabits diverse aquatic environments across North America, including flowing water, standing water, and temporary habitats. The species was described by S.I. Smith in 1871.
Crangonyx richmondensis
Ellis Bog Crangonyctid
A small freshwater amphipod crustacean endemic to North America. The species exhibits an annual life cycle with distinct seasonal breeding patterns. Populations are restricted to specific freshwater habitats with particular substrate and vegetation characteristics. Two subspecies have been described: C. r. richmondensis and C. r. laurentianus, with the latter studied in detail in Algonquin Park, Ontario.
Ericthonius
Ericthonius is a genus of marine amphipod crustaceans in the family Ischyroceridae, first described by H. Milne Edwards in 1830. The genus contains at least 20 described species, with records from marine coastal waters of northern Europe. These small crustaceans are part of the diverse benthic communities inhabiting shallow marine environments.
Gammaridae
gammarids, scuds
Gammaridae is a family of amphipod crustaceans with a distribution centered on Eurasia. The family exhibits euryhaline tolerance as a lineage, inhabiting environments from freshwater to marine waters. Historically, Gammaridae served as a wastebin taxon for numerous gammaridean amphipods, many of which have since been reassigned to separate families including Anisogammaridae, Melitidae, and Niphargidae. In North America, members are commonly referred to as scuds.
Gammaridea
Gammaridea was historically recognized as a suborder of Amphipoda encompassing approximately 7,275 species (92% of described amphipods) across ~1,000 genera and ~125 families. The group included nearly all freshwater amphipods alongside numerous marine species. Taxonomic revisions by Lowry and Myers (2003–2017) demonstrated that Gammaridea was paraphyletic, leading to its deconstruction into new suborders: Corophiidea (2003), Senticaudata (2013), and Amphilochoidea (2017). The name Gammaridea is no longer recognized as a valid taxon in current amphipod classification.
Gammarus
scuds, freshwater shrimp, sideswimmers
Gammarus is a genus of amphipod crustaceans in the family Gammaridae, containing over 200 described species and representing one of the most species-rich crustacean genera. Species occupy diverse aquatic habitats ranging from purely freshwater to estuarine and marine environments, with salinity tolerance varying markedly among species. The genus is widely distributed throughout the Holarctic region, with additional species extending into tropical Southeast Asia. Gammarus species serve important ecological functions as shredders and predators in aquatic food webs.
Gammarus fasciatus
Gammarus fasciatus is a freshwater amphipod native to North America. Laboratory studies demonstrate that food type significantly influences growth rates, with algae and animal matter supporting greater growth than detritus-based diets. The species serves as a host for the acephaline gregarine parasite Ganymedes oaklandi. In the Great Lakes region, populations have declined due to competition with the invasive Ponto-Caspian amphipod Echinogammarus ischnus.
Gammarus locusta
scud
Gammarus locusta is a marine amphipod crustacean in the family Gammaridae, commonly known as a scud. It inhabits coastal and estuarine environments with a cosmopolitan distribution in European waters. The species has been extensively studied as a model organism for ecotoxicology, particularly regarding responses to ocean acidification, warming, deoxygenation, and pharmaceutical contaminants. Research indicates it possesses the ability to biosynthesize or retain essential long-chain polyunsaturated fatty acids, making it of interest for aquaculture applications.
Gammarus mucronatus
scud
Gammarus mucronatus is a small amphipod crustacean first described in 1818. It is a dominant species in salt marsh and estuarine habitats along the North American Atlantic coast and Gulf of Mexico. The species is multivoltine, producing multiple broods per season with overlapping cohorts. It serves as an important food source for fish and other predators while contributing significantly to energy flow and nutrient cycling in coastal ecosystems.
Gammarus pseudolimnaeus
Northern Spring Amphipod
Gammarus pseudolimnaeus is a freshwater amphipod crustacean inhabiting lotic (flowing water) environments in North America. The species exhibits complex behavioral ecology, including size-selective predation vulnerability to fish predators such as brook trout and sculpins, and chemically-mediated responses to predation risk that influence reproductive behavior. Population dynamics are characterized by univoltine (single annual) generation cycles with high mortality during early life stages and winter periods. The species serves as an important prey item in stream food webs and has been extensively studied as a model organism for freshwater invertebrate ecology, toxicology, and predator-prey interactions.
freshwaterloticamphipodpredator-preybehavioral-ecologytoxicologyunivoltineNorth-Americamodel-organismstream-ecologysize-selective-predationchemical-ecologyparasitismacanthocephalacopper-toxicitymate-guardingcalceolimicrohabitat-selectionthigmotaxisdiel-activityseasonal-dynamicsproduction-ecologydriftbrook-troutsculpinOntarioVirginiaGammaridaecrustaceaninvertebratesenticaudataBousfield-1958Northern-Spring-AmphipodHaustoriidae
Haustoriidae is a family of amphipod crustaceans characterized by stout, robust bodies adapted for burrowing in sandy sediments. They are dominant members of intertidal and shallow subtidal sandy beach communities along the Atlantic coast of North America, with some species extending into the Gulf of Mexico and Pacific coast. The family radiated during the Eocene, with the Pacific-endemic genus Eohaustorius representing the most basal lineage, diverging approximately 31 million years ago. Haustoriidae are distinguished from other amphipod families by their specialized morphology for sand-burrowing and their limited dispersal capabilities, which have resulted in strong population structure and cryptic diversity across their range.
Hyalella azteca
scud, freshwater scud
Hyalella azteca is a widespread and abundant amphipod crustacean in North America, reaching 3–8 mm in length. It inhabits fresh and brackish waters across a broad geographic range from Central America to the Arctic tree line. The species is a significant food source for waterfowl and serves as a standard test organism in aquatic ecotoxicology and sediment toxicity assessments.
Hyalella wellborni
Hyalella wellborni is a freshwater amphipod species in the family Hyalellidae, described in 2015 from the southeastern United States. The genus Hyalella comprises small benthic crustaceans commonly known as scuds or sideswimmers, widespread in lakes, ponds, and streams. H. wellborni represents part of a taxonomically complex group where species delineation has historically relied on morphological and molecular analyses. The species is known from a limited number of observations, reflecting both its relatively recent description and the ongoing challenges in amphipod taxonomy.
Hyperia
Hyperia is a genus of amphipod crustaceans in the family Hyperiidae, established by Latreille in 1823. Members of this genus are known for their parasitic or commensal associations with gelatinous zooplankton, particularly jellyfish (Cnidaria). The genus includes species such as Hyperia medusarum, which has been documented as a parasite of scyphozoan and hydrozoan medusae in the southeastern Atlantic Ocean.
Jassa marmorata
Marbled Scud
A tube-building amphipod native to the northeast Atlantic Ocean, now introduced to northeast Asia. Distinguished by greyish coloration with reddish-brown markings and a maximum length of 10 mm. Notable for exhibiting two distinct male morphs with alternative mating strategies: larger 'major' males that fight for access to females, and smaller 'minor' males that sneak copulations. Constructs protective tubes from detritus and algae fragments bound with mucus secretions.
Mexiweckelia hardeni
Mexiweckelia hardeni is a species of amphipod crustacean in the family Hadziidae, first described by Holsinger in 1992. The genus Mexiweckelia is part of a group of amphipods adapted to subterranean or aquatic habitats. As a member of Hadziidae, it likely inhabits groundwater or cave systems, though specific ecological details remain poorly documented. The species is known from limited collection records in the Nearctic region.
Orchestia
Orchestia is a genus of talitrid amphipods comprising approximately 10-15 marine supralittoral species. The genus was revised in 2014, with three new species described from the North Atlantic and South America, and has been redefined to exclude terrestrial species now placed in Cryptorchestia. Species in this genus inhabit coastal environments including sandy beaches, driftwood, and estuaries, with some showing specialized ecological associations. Orchestia species serve as intermediate hosts for parasites and play roles in wrack decomposition.
Platorchestia platensis
sand flea
Platorchestia platensis is a talitrid amphipod commonly known as a sand flea, inhabiting sandy beach environments. It is a laterally compressed crustacean adapted for jumping and burrowing in intertidal zones. The species has been documented across Atlantic and Mediterranean coastal regions, including the Azores and Wadden Sea. It plays a role in beach ecosystem dynamics as a detritivore and prey item for shorebirds.
Ramellogammarus
Stumptown scud (R. similimanus)
Ramellogammarus is a genus of freshwater amphipod crustaceans in the family Anisogammaridae, established by Bousfield in 1979. The genus includes species with highly restricted geographic distributions in the Pacific Northwest of North America. R. similimanus, known as the Stumptown scud, is endemic to the Portland metropolitan area of Oregon, while R. vancouverensis occurs in British Columbia.
Stygobromus pecki
Peck's cave amphipod
Stygobromus pecki is a small, eyeless, unpigmented cave-dwelling amphipod endemic to four spring systems in Comal County, Texas. It is a federally listed endangered species in the United States and classified as Endangered on the IUCN Red List due to its extremely limited geographic distribution. The species inhabits subterranean limestone aquifers and exhibits adaptations typical of stygobitic organisms, including light sensitivity and starvation resistance. Very few individuals have been documented since its listing, and no formal recovery plan or comprehensive population assessment exists as of 2022.
Talitridae
Sandhoppers, Landhoppers
Talitridae is a family of amphipod crustaceans encompassing diverse ecological forms including beach-dwelling sandhoppers, terrestrial landhoppers, and specialized driftwood hoppers. Members occupy habitats ranging from marine intertidal zones to fully terrestrial environments in rainforest leaf litter and caves. The family exhibits remarkable physiological adaptations for desiccation resistance and aerial respiration, with some Southern Hemisphere species being entirely terrestrial. Ecological diversity within Talitridae includes wrack generalists, psammophilic burrowers, palustral salt marsh dwellers, xylophagous driftwood specialists, and freshwater forms.
Traskorchestia
beach hoppers
Traskorchestia is a genus of beach hoppers in the family Talitridae, established by Bousfield in 1982. The genus contains at least three described species: T. georgiana, T. ochotensis, and T. traskiana (the Pacific beach hopper). These amphipods inhabit coastal environments and are part of the supralittoral community.
Traskorchestia traskiana
Pacific beach hopper
Traskorchestia traskiana, the Pacific beach hopper, is a supralittoral amphipod inhabiting coastal beaches of the Pacific Northwest. Its activity patterns are directly influenced by tidal inundation cycles, with behavioral adaptations to periodic flooding in the zone above the high tide line. The species has been studied for its population biology and behavioral responses to environmental conditions in nearshore ecosystems.
Uhlorchestia
beach hoppers
Uhlorchestia is a genus of talitrid amphipods endemic to salt marshes along the Atlantic coast of North America. The genus contains two described species: U. spartinophila and U. uhleri. These amphipods are closely associated with smooth cordgrass (Spartina alterniflora) and function as detritivores in salt marsh ecosystems. Population studies indicate high turnover rates and year-round reproduction with seasonal peaks.
Unciolidae
Unciolidae is a family of marine amphipod crustaceans comprising approximately 9 genera and over 20 described species. The family has a worldwide distribution with records from deep-sea environments in the North Atlantic and shallow tropical waters such as the Great Barrier Reef. Members of this family exhibit diverse habitat preferences, from abyssal depths exceeding 2000 meters to coastal reef systems.