WAristaeomorpha is a genus of deep water prawns from the family Aristeidae.
WAstacus is a genus of crayfish found in Europe and western Asia, comprising three extant and four extinct, fossil species.
WAtergatis is a genus of crabs in the family Xanthidae, containing the following species:
WAustropotamobius is a genus of European crayfish in the family Astacidae. It contains four extant species, and one species known from fossils of Barremian age:Austropotamobius llopisi (Via, 1971) † Austropotamobius italicus (Faxon, 1914) Austropotamobius pallipes (Lereboullet, 1858) — White-clawed crayfish Austropotamobius torrentium (Schrank, 1803) — Stone crayfish Austropotamobius bihariensis Pârvulescu 2019 — Idle crayfish
WEiconaxius is a genus of mud lobster that includes the following species:Eiconaxius acutifrons Bate, 1888 Eiconaxius agassizi Bouvier, 1905 Eiconaxius albatrossae Kensley, 1996 Eiconaxius andamanensis Eiconaxius antillensis Bouvier, 1905 Eiconaxius asper Rathbun, 1906 Eiconaxius baja Kensley, 1996 Eiconaxius bandaensis Sakai, 2011 Eiconaxius borradailei Bouvier, 1905 Eiconaxius caribbaeus Eiconaxius consobrinus Eiconaxius cristagalli Eiconaxius demani Sakai, 1992 Eiconaxius dongshaensis Poore & Dworschak, 2018 Eiconaxius farreae Ortmann, 1891 Eiconaxius gololobovi Poore & Dworschak, 2018 Eiconaxius hakuhou Sakai & Ohta, 2005 Eiconaxius heinrichi Eiconaxius indicus Eiconaxius kensleyi Komai, Lin & Chan, 2010 Eiconaxius kermadeci Bate, 1888 Eiconaxius kimbla Kensley, 1996 Eiconaxius kumejimaensis Sakai, 2014 Eiconaxius laccadivensis Alcock & Anderson, 1894 Eiconaxius malaku Poore, 2017 Eiconaxius mallacoota Poore & Collins, 2009 Eiconaxius mortenseni Sakai, 1992 Eiconaxius parvus Bate, 1888 Eiconaxius rubrirostris Komai, Lin & Chan, 2010 Eiconaxius sibogae Eiconaxius singularis Eiconaxius spiniger Eiconaxius vaubani Poore, 2017 Eiconaxius weberi
WEngaeus is a genus of freshwater crayfish found in Australia, the burrowing crayfishes. Fifteen of the 35 species in the genus occur in Tasmania, where they are known as the Tasmanian land crayfishes. The behaviour of these crayfish is notable as they live in burrows and construct large "chimneys" at the opening.
WReef lobsters, Enoplometopus, are a genus of small lobsters that live on reefs in the Indo-Pacific, Caribbean and warmer parts of the Atlantic Ocean.
WEuastacus is a genus of freshwater crayfish known as "spiny crayfish". They are found in the south-east of the Australian mainland, along with another genus of crayfish, Cherax. Both genera are members of the family Parastacidae, a family of freshwater crayfish restricted to the Southern Hemisphere.
WEuphausia is the largest genus of krill, and is placed in the family Euphausiidae. There are 31 species known in this genus, including Antarctic krill and ice krill from the Southern Ocean, and North Pacific krill in the Pacific Ocean.
WEurythenes is a genus of marine amphipods in the family Eurytheneidae.
WHawaiioscia is a genus of woodlouse known from the Hawaii, Rapa Nui, and Costa Rica. The genus was originally described from Hawaii on the presence of four troglobitic species on separate islands. A species within this genus was then described from Rapa Nui which lacked troglobtic traits, but only persists in cave-dwelling relict populations. Surprisingly, another species was then described from along the Pacific Coast of Costa Rica.
WHeterosaccus is a genus of barnacles in superorder Rhizocephala. Like other taxa in this superorder, they parasitize crabs. Geoffroy Smith circumscribed the genus in 1906; he initially only included H. hians. Smith circumscribed a genus distinct from Sacculina due to a difference of the mesentery; in Heterosaccus, the mesentery does not stretch down to the mantle opening but rather only is present on the ring of attachment.
WJasus is a genus of spiny lobsters which live in the oceans of the Southern Hemisphere. They have two distinct "horns" projecting from the front of the carapace, but lack the stridulating organs present in almost all other genera of spiny lobsters. Like all spiny lobsters, they lack claws, and have long stout antennae which are quite flexible.
WLepeophtheirus is a genus of sea lice. The best-known species is L. salmonis, the salmon louse. Other species include L. pectoralis, which uses flatfish as its host, particularly the European flounder, and is also the type species of the genus Lepeophtheirus.
WLeptomithrax is a genus of crabs in the family Majidae. They have been on Earth for 37.2 million years.
WLybia is a genus of small crabs in the family Xanthidae. Their common names include boxer crabs, boxing crabs and pom-pom crabs. They are notable for their mutualism with sea anemones, which they hold in their claws for defense. In return, the anemones get carried around which may enable them to capture more food particles with their tentacles. Boxer crabs use at least three species of anemones, including Bundeopsis spp. and Triactis producta. The bonding with the anemone is not needed for survival, however, and boxer crabs have frequently been known to live without them, sometimes substituting other organisms such as sponges and corals for the sea anemones.
WMesoniscus is a genus of woodlice, placed in its own family, Mesoniscidae, and section, Microcheta. It contains two species – Mesoniscus alpicolus and Mesoniscus graniger – that live in Central and Eastern Europe, mostly in and around caves.
WMetapenaeus is a genus of prawns, containing the following species:
WMirocaris is a genus of shrimp associated with hydrothermal vents. Sometimes considered the only genus of the family Mirocarididae, Mirocaris is usually placed in the family Alvinocarididae. The genus contains two species, M. fortunata and M. indica; the former species M. keldyshi is now considered synonymous with M. fortunata. The two species are found in different oceans, and can be distinguished by the pattern of setation on the claw of the first pereiopod.
WNebalia is a large genus of small crustaceans containing more than half of the species in the order Leptostraca, with over thirty species:
WNematoscelis is a genus of krill, containing the following species:Nematoscelis atlantica Hansen, 1910 Nematoscelis difficilis Hansen, 1911 Nematoscelis gracilis Hansen, 1910 Nematoscelis lobata Hansen, 1916 Nematoscelis megalops G. O. Sars, 1883 Nematoscelis microps G. O. Sars, 1883 Nematoscelis tenella G. O. Sars, 1883
WNiphargus is by far the largest genus of its family, the Niphargidae, and the largest of all freshwater amphipod genera.
WOrconectes is a genus of cave dwelling freshwater crayfish, native to the eastern United States and Canada. Surface dwelling species, formerly categorised here were moved to Faxonius in 2017.
WPacifastacus is a genus of crayfish native to western North America, containing the following six species :Pacifastacus chenoderma Pacifastacus connectens Pacifastacus fortis – shasta crayfish Pacifastacus gambelii Pacifastacus leniusculus – signal crayfish Pacifastacus nigrescens
WPanulirus is a genus of spiny lobsters in the family Palinuridae, including those species which have long flagella on their first antennae.
WParanephrops is a genus of freshwater crayfish found only in New Zealand. They are known by the English common names freshwater crayfish and koura, the latter from their Māori name of kōura. The two species are the northern koura, Paranephrops planifrons, found mainly in the North Island, but also in Marlborough, Nelson, and the West Coast of the South Island, and the southern koura, Paranephrops zealandicus, found only in the eastern and southern of the South Island and on Stewart Island/Rakiura. Both species are a traditional food for Māori, and a small koura aquaculture industry supplies the restaurant market.
WPenaeus is a genus of prawns, including the giant tiger prawn, the most important species of farmed crustacean worldwide. The genus has been reorganised following a proposition of Pérez Farfante and Kensley based on morphological differences, in particular the genital characteristics of these animals, although this revision has not been universally accepted. Following the revision, many species formerly in the genus Penaeus have been reassigned to new genera in the family Penaeidae: Farfantepenaeus, Fenneropenaeus, Litopenaeus and Marsupenaeus. The following table gives an overview:
WPercnon is a genus of crabs. It is "doubtfully placed" in the family Plagusiidae, and it has also been included in the family Grapsidae.
WPercnon planissimum or flat rock crab is a species of Percnon crab found in the Indo-Pacific from Somalia to Cocos Islands, the Philippines and Kermadec Islands.
WPotamon is a genus of freshwater or semiterrestrial crabs mainly found from Southern Europe through the Middle East, and as far east as north-western India. The only exception is the North African P. algeriense, which also is the only potamid of mainland Africa. Twenty species are currently recognised:. These crabs are omnivores that have a broad ecological tolerance. The adult Potaman reach up to 50 mm in size during their 10-12 year life span.
WProcambarus is a genus of crayfish in the family Cambaridae, all native to North and Central America. It includes a number of troglobitic species, and the marbled crayfish (marmorkrebs), which is parthenogenetic. Originally described as a subgenus for four species, it now contains 161 species in 16 subgenera.
WSacculina is a genus of barnacles that is a parasitic castrator of crabs. They belong to a group called Rhizocephala. The adults bear no resemblance to the barnacles that cover ships and piers; they are recognised as barnacles because their larval forms are like other members of the barnacle class Cirripedia. The prevalence of this crustacean parasite in its crab host can be as high as 50%.
WStenopus is a genus of swimming decapod crustaceans containing eleven species, including Stenopus hispidus, a common aquarium pet. Stenopus contains the following species:
WStenorhynchus is a genus of marine crabs in the family Inachidae, containing the following species:Stenorhynchus debilis (S. I. Smith, 1871) Stenorhynchus lanceolatus (Brullé, 1837) Stenorhynchus seticornis (J. F. W. Herbst, 1788) – yellowline arrow crab Stenorhynchus yangi Goeke, 1989 – red arrow crab
WStygobromus is a genus of amphipod crustaceans that live in subterranean habitats. As well as a large number of species in 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); all the listed species are endemic to the United States. One species, S. lucifugus, is extinct. Stygobromus includes the following species:
WThemisto is a genus of marine amphipods in the family Hyperiidae. Their distribution is cosmopolitan.
WThermosphaeroma is a genus of crustacean in family Sphaeromatidae. They occur exclusively in hot springs of southwestern United States and central Mexico.
WThysanoessa is a genus of krill, containing the following species:Thysanoessa gregaria G. O. Sars, 1885 Thysanoessa inermis (Krøyer, 1846) Thysanoessa inspinata Nemoto, 1963 Thysanoessa longicaudata (Krøyer, 1846) Thysanoessa longipes Brandt, 1851 Thysanoessa macrura G. O. Sars, 1885 Thysanoessa parva Hansen, 1905 Thysanoessa raschii (M. Sars, 1864) Thysanoessa spinifera Holmes, 1900 Thysanoessa vicina Hansen, 1911
WUrothoe is a genus of very small marine amphipod crustaceans in the family Urothoidae. Members of the genus are found worldwide.