''Narke'' (from

ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

ναρκῶ ''narkō'', "to make numb") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

electric ray The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, composing the order Torpediniformes . They are known for being capable of producing an electric discharge, ranging from 8 to 220 volts, depending ...

s in the family

Narkidae Members of the family Narkidae are commonly known as sleeper rays. They are restricted to the temperate and tropical Indo-West Pacific from South Africa to Japan to Indonesia, and are exclusively marine and are absent from freshwater habitats. ...

, found in the

western Indo-Pacific The Western Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the eastern and central Indian Ocean. It is part of the larger Indo-Pacific, which includes the tropical Indian Ocean, the western and centr ...

and off

southern Africa Southern Africa is the southernmost region of Africa. No definition is agreed upon, but some groupings include the United Nations geoscheme for Africa, United Nations geoscheme, the intergovernmental Southern African Development Community, and ...

. They have nearly circular

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

discs and short, thick tails with large

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

s, and can be identified by their single

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

(a trait shared only by ''

Typhlonarke ''Typhlonarke'' is a genus of sleeper ray in the family Narkidae, containing two poorly known species. The group is known for producing electric shocks for defense. Both species are deep-sea rays endemic to the waters off New Zealand. They are ...

'' within the family). There are three described

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, as well as a fourth undescribed dwarf species from

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Species

* ''

Narke capensis The onefin electric ray or Cape numbfish (''Narke capensis'') is a common but little-known species of electric ray in the family Narkidae, native to South Africa and Namibia. It is a benthic fish found in shallow coastal bays over sandy or muddy ...

'' J. F. Gmelin, 1789 (Onefin electric ray) * ''

Narke dipterygia The numbray or spottail sleeper ray (''Narke dipterygia'') is a species of electric ray in the family Narkidae Members of the family Narkidae are commonly known as sleeper rays. They are restricted to the temperate and tropical Indo-West Paci ...

Bloch Bloch is a surname of German origin. Notable people with this surname include: A *Adele Bloch-Bauer (1881–1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter *Alexandre Bloch (1857–1919), French painter *Alfred Bloch ( ...

& Schneider, 1801 (Numbray) * ''

Narke japonica The Japanese sleeper ray (''Narke japonica'') is a species of electric ray in the family Narkidae. It is common in the inshore and offshore waters of the northwestern Pacific Ocean from southern Japan to southern China. Growing up to long, the J ...

Temminck Coenraad Jacob Temminck (; 31 March 1778 – 30 January 1858) was a Dutch patrician, zoologist and museum director. Biography Coenraad Jacob Temminck was born on 31 March 1778 in Amsterdam in the Dutch Republic. From his father, Jacob ...

Schlegel Schlegel is a German occupational surname. Notable people with the surname include: * Anthony Schlegel (born 1981), American football player * August Wilhelm Schlegel (1767–1845), German poet, brother of Friedrich * Brad Schlegel (born 1968), C ...

, 1850 (Japanese sleeper ray)

References

Narkidae Ray genera Taxa named by Johann Jakob Kaup Strongly electric fish {{batoid-stub