Remipedia is a class of blind crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s found in coastal aquifer

Aquifer

An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...

s which contain saline groundwater, with populations identified in almost every ocean basin so far explored, including in Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, the Caribbean Sea

Caribbean Sea

The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....

, the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

. The first described remipede was the fossil Tesnusocaris goldichi

Tesnusocaris goldichi

Tesnusocaris goldichi was a species of crustacean that lived in the Pennsylvanian period, the only representative of the extinct Order Enantiopoda . Its fossil is from the Lower Pennsylvanian , Tesnus formation, Texas....

(Lower Pennsylvanian), but, since 1979, at least seventeen living species have been identified with global distribution throughout the neo-tropical zone.

Remipedes are 10–40 mm (0.393700787401575–1.6 in) long and comprise a head and an elongate trunk of up to forty-two similar body segments. The swimming appendage

Appendage

In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...

s are lateral on each segment, and the animals swim on their backs. They are generally slow-moving. They have fangs connected to secretory glands; it is still unknown whether these glands secrete digestive juices or poisonous venom, or whether remipedes feed primarily on detritus or on living organisms. They have a generally primitive body plan in crustacean terms, and have been thought to be a basal, ancestral crustacean group. However, Fanenbruck et al. showed that at least one species, Godzilliognomus frondosus, has a highly organised and well-differentiated brain, with a particularly large olfactory area which is a common feature for species that live in dark environments. The size and complexity of the brain suggested to Fanenbruck et al. that Remipedia might be the sister taxon to Malacostraca

Malacostraca

Malacostraca is the largest of the six classes of crustaceans, containing over 25,000 extant species, divided among 16 orders. Its members display a greater diversity of body forms than any other class of animals, and include crabs, lobsters, shrimp, krill, woodlice, scuds , mantis shrimp and many...

, regarded as the most advanced of the crustaceans. This is also one of the reasons why it is included in the Pancrustacea

Pancrustacea

Pancrustacea is a clade, comprising all crustaceans and hexapods. This grouping is contrary to the Atelocerata hypothesis, in which Myriapoda and Hexapoda are sister taxa, and Crustacea are only more distantly related. As of 2010, the Pancrustacea taxon is considered well accepted. The clade has...

 hypothesis, a hypothethical clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of probably the most advanced Mandibulata

Mandibulata

The Mandibulata or mandibulates is a clade of arthropods that comprises the extant subphyla Myriapoda , Crustacea and Hexapoda . Mandibulata is currently believed to be the sister group of the clade Arachnomorpha, which comprises the rest of arthropods...

. They have also been grouped together with the Cephalocarida

Cephalocarida

Cephalocarida is a class inside the subphylum Crustacea that comprises only twelve shrimp-like benthic species. They were discovered in 1955 by Howard L. Sanders, and are commonly referred to as horseshoe shrimps. They have been grouped together with the Remipedia in the Xenocarida...

 in the Xenocarida

Xenocarida

Xenocarida is a clade inside the subphylum Crustacea that comprises two classes that were discovered in the 20th century: Remipedia and Cephalocarida. Xenocarida is the sister clade of Hexapoda....

.

Classification

Twenty extant species are currently recognised, divided among three families. All are placed in the order Nectiopoda; the second order, Enantiopoda, comprises the single fossil species Tesnusocaris goldichi.

Godzilliidae

• Godzilliognomus Yager, 1989
  • Godzilliognomus frondosus Yager, 1989
  • Godzillognomus schrami
    Godzillognomus schrami
    Godzilliognomus schrami is a species of Remipedia discovered in 2007, representing one of five extant species of the family Godzilliidae. It generally reaches about in length and inhabits a single anchialine cave on Grand Bahama Island. The specific epithet commemorates Frederick Schram....
    
    Iliffe et al., 2010
• Godzillius Schram et al., 1986
  • Godzillius robustus Schram et al., 1986
• Pleomothra Yager, 1989
  • Pleomothra apletocheles Yager, 1989
  • Pleomothra fragilis Koenemann et al., 2008

Micropacteridae

• Micropacter Koenemann et al., 2007
  • Micropacter yagerae Koenemann et al., 2007

Speleonectidae

• Cryptocorynetes Yager, 1987
  • Cryptocorynetes elmorei Hazerli et al., 2009 
  • Cryptocorynetes haptodiscus Yager, 1987
  • Cryptocorynetes longulus Wollermann et al., 2007
• Kaloketos Koenemann et al., 2004
  • Kaloketos pilosus Koenemann et al., 2004
• Lasionectes Yager & Schram, 1986
  • Lasionectes entrichoma Yager & Schram, 1986
  • Lasionectes exleyi Yager & Humphreys, 1996
• Speleonectes Yager, 1981
  • Speleonectes atlantida
    Speleonectes atlantida
    Speleonectes atlantida is a species of eyeless crustacean in the order Nectiopoda. It was discovered in August 2009 in the Tunnel de la Atlantida, the world's longest submarine lava tube on Lanzarote in the Canary Islands off the west coast of North Africa...
    
    Koenemann et al., 2009
  • Speleonectes benjamini Yager, 1987
  • Speleonectes emersoni Lorentzen et al., 2007
  • Speleonectes epilimnius Yager & Carpenter, 1999
  • Speleonectes gironensis Yager, 1994
  • Speleonectes kakukii Daenekas et al., 2009
  • Speleonectes lucayensis Yager, 1981
  • Speleonectes minnsi Koenemann, Iliffe & van der Ham, 2003
  • Speleonectes ondinae (Garcia-Valdecasas, 1984)
  • Speleonectes parabenjamini Koenemann, Iliffe & van der Ham, 2003
  • Speleonectes tanumekes Koenemann, Iliffe & van der Ham, 2003
  • Speleonectes tulumensis Yager, 1987

Distribution of extant Remipedia

– Andros

Andros, Bahamas

Andros Island is an archipelago within the archipelago-nation of the Bahamas, the largest of the 26 inhabited Bahamian Islands. Geo-politically considered a single island, Andros has an area greater than all the other 700 Bahamian islands combined...

, Sweetings Cay, Grand Bahama

Grand Bahama

Grand Bahama is one of the northernmost of the islands of the Bahamas, and the closest major island to the United States, lying off the state of Florida. Grand Bahama is the fifth largest island in the Bahamas island chain of approximately 700 islands and 2,400 cays...

, Great Exuma, Great Guana Cay

Great Guana Cay

Great Guana Cay is an islet located in The Bahamas. It is a long but narrow islet which is 9 miles in length. It is located in the centre of the Abaco Islands...

 (Exuma Cays), Cat Island, Abaco Islands

Abaco Islands

The Abaco Islands lie in the northern Bahamas and comprise the main islands of Great Abaco and Little Abaco, together with the smaller Wood Cay, Elbow Cay, Lubbers Quarters Cay, Green Turtle Cay, Great Guana Cay, Castaway Cay, Man-o-War Cay, Stranger's Cay, Umbrella Cay, Walker's Cay, Little Grand...

, San Salvador Island

San Salvador Island

San Salvador Island, also known as Watlings Island, is an island and district of the Bahamas. Until 1986, when the National Geographic Society suggested Samana Cay, it was widely believed that during his first expedition to the New World, San Salvador Island was the first land sighted and visited...

 – North Caicos

North Caicos

North Caicos is the second-largest island in the Turks and Caicos Islands. To the west, the Caicos Cays link to Providenciales. To the east, it is separated from Middle Caicos by Juniper Hole, a narrow passage that can accommodate only small boats.North Caicos has an area of 116.4 km² within the...

, Providenciales

Providenciales

Providenciales is an island in the Turks and Caicos Islands. The island has an area of and an approximate population of 15,542, making it the largest island in population and the third largest in area. It is served by the Providenciales International Airport...

 – North West Cape

North West Cape

North West Cape is a large peninsula of land in the north west coast of Western Australia. Cape Range runs down the spine of the peninsula and Ningaloo Reef runs along the western edge...

 (Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

) – Matanzas Province

Matanzas Province

Matanzas is one of the provinces of Cuba. Major towns in the province include Cárdenas, Colón, Jovellanos and the capital of the same name, Matanzas...

 – Lanzarote

Lanzarote

Lanzarote , a Spanish island, is the easternmost of the autonomous Canary Islands, in the Atlantic Ocean, approximately 125 km off the coast of Africa and 1,000 km from the Iberian Peninsula. Covering 845.9 km2, it stands as the fourth largest of the islands...

 (Canary Islands

Canary Islands

The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...

) – Quintana Roo

Quintana Roo

Quintana Roo officially Estado Libre y Soberano de Quintana Roo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 10 municipalities and its capital city is Chetumal....

 – Distrito Nacional

Distrito Nacional

The Distrito Nacional is a subdivision of the Dominican Republic enclosing the capital Santo Domingo. It is not within any of the provinces, but is itself counted as a province. Before October 16, 2001, the Distrito Nacional was much larger, including what is now known as Santo Domingo Province....