Epimeriidae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of relatively large

amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...

found in cold oceans around the world.

Distribution, habitat and abundance

Members of this family range from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

to a depth of , but overall mostly and in the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smal ...

mostly . The highest

species richness Species richness is the number of different species represented in an ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the abundances of the species or their relative ab ...

is in the Southern Ocean south of the

Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters p ...

, followed by deep parts of the Pacific Ocean, with only a few elsewhere, including the

Magellanic Magellanic may refer to: *Magellanic Steppe, 7th largest desert in the world, see Patagonian Desert *Magellanic Straits, a sea passageway at the tip of South America, see Strait of Magellan *Magellanic subpolar forests, an ecoregion of southernmost ...

region, Indian Ocean, Atlantic Ocean (both north and south) and

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. In tropical and warm-temperate regions they only occur in deep, cold waters. The vast majority are generally slow-moving and

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

, but can move fast for short distance and a few species are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

or semi-pelagic. The family includes both species that are widespread and species with small ranges (typically restricted to an island,

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise a ...

ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

), and very common species and rare species. Their abundance is often directly related to the

epifauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as ''biota''. Zoolo ...

abundance: Where the epifauna is rich and diverse, so are Epimeriidae. A few species have been kept, bred and studied in cold-water () aquariums by scientists.

Appearance and behavior

They are relatively large amphipods, with adults of the various species ranging from in head-and-body length. They are typically white, yellowish, orange, pinkish, red or purplish, and some have quite striking colour patterns. Some have a spiny crest along their mid-back and spines on their sides, which may serve as a protection against fish or serve as a "disruptive shape" (similar to

disruptive colouration Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military vehicle with a strongly contrasting pattern. It is often comb ...

) that camouflages the amphipod. Most species are predators or scavengers that feed on bethic invertebrates (such as small crustaceans,

brittle star Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locom ...

sea cucumber Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothu ...

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

cnidarian Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in Fresh water, freshwater and Marine habitats, marine environments, predominantly the latter. Their distinguishing feature is cnidocyt ...

s and

polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are ...

s), or

suspension feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

s that take

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...

(such as diatoms,

radiolaria The Radiolaria, also called Radiozoa, are protozoa of diameter 0.1–0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm. The elab ...

ns and

foraminifer Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly ...

s). Some are opportunistic feeders that will take a wide range of prey-types, while other species are specialists on one or a few prey types, like

hydroids Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish. Some hydroids such as the freshwater ''Hydra'' are solitary, with the polyp attached directly to the substrate. When these produce buds, ...

. ''Epimeria parasitica'' is a

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...

on sea cucumbers. The newly hatched young resemble miniature versions of the adults (there is no larvae stage). They may climb onto their mother and stay with her for a period, but in other species they leave immediately.

Taxonomy and genera

Two genera are placed in this family by the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific speciali ...

. A few others were formerly included, but are now regarded as subgenera (not full genera) or placed in other families ('' Actinacanthus'' in family Acanthonotozomellidae and '' Paramphithoe'' in family Paramphithoidae). *''

Epimeria ''Epimeria'' is a genus of amphipods in the family Epimeriidae. There are more than 80 described species in ''Epimeria''. Species These 85 species belong to the genus ''Epimeria'': * ''Epimeria abyssalis'' Shimomura & Tomikawa, 2016 * ''Epimeri ...

'' Costa, 1851 *''

Uschakoviella ''Uschakoviella'' is a genus of amphipods in the family Epimeriidae Epimeriidae is a family of relatively large amphipods found in cold oceans around the world. Distribution, habitat and abundance Members of this family range from the intert ...

'' Gurjanova, 1955 With more than 80 described species, ''Epimeria'' is by far the most diverse genus in the family, has been the target of several studies and is considered among the most iconic

taxa In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

in Southern Ocean. Nevertheless, many aspects of their life is poorly known, several new species have been described in the last decade and it is likely that several

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and name ...

remain. There is only a single species in the genus ''Uschakoviella''.

References

External links

Antarctic Ice Breakups Reveal New Species
at National Geographic, showing a photograph of a potentially new species of ''Epimeria'' * {{Taxonbar, from=Q3933391 Gammaridea Crustacean families