Narcinidae
Encyclopedia
The numbfishes are a group of electric ray
s (order Torpediniformes) in the family Narcinidae. They are bottom-dwelling cartilaginous fishes with large, rounded pectoral fin discs and long tails. They can produce an electric discharge
for defense, from which their scientific name is derived (Greek
narke, meaning "paralysis").
Members of this family are commonly known as the numbfishes, and are found almost worldwide in warm temperate and tropical continental and continental insular waters. They are strictly marine and are absent from river
s and lake
s. They occur in sand
y beach
es, muddy enclosed bay
s, estuaries, off coral reef
s and river mouths, and on the upper continental slope to a depth of 1,071 meters.
-shaped pectoral discs and stout tails of equal or longer length. The snout is moderately elongated, rounded or rounded-angular, differing from the narkids in being supported by broad rostral cartilage
s. The mouth is straight, with stout, elongated, and highly protrusible jaws and a prominent groove around its periphery. The nostril
s are just forward of the mouth and connected to it by a broad groove; the nasal flaps are short but merged into a broad nasal curtain that overlaps the mouth. The teeth are small have a single moderate cusp; the teeth and tooth bands are exposed when the mouth is closed (except in Diplobatis). There are two prominent dorsal fin
s of roughly equal size, and a large caudal fin.
Numbfishes vary in color from whitish, yellowish, brownish, grey-brown, greenish, reddish, or black above, either plain or with small to large spots, blotches, bars or lines, sometimes forming complex eye-shaped spots or ocelli on the pectoral fins. They are usually white underneath, or black in deep-water species. The large, kidney
-shaped electric organs are at the base of the pectoral fins and visible through the skin.
es and invertebrate
s off the bottom; their protrusible jaws aid in removing prey from the substrate. They can generate a moderate shock if disturbed and contact is made with the electric organs; the electrical discharges of narcinids have been measured at 8-37 volt
s, much less than the electric rays of the genus Torpedo
. All species are ovoviviparous, with eggs hatching inside the mother.
Electric ray
The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, comprising the order Torpediniformes. They are known for being capable of producing an electric discharge, ranging from as little as 8 volts up to 220 volts depending on species, used to stun prey and...
s (order Torpediniformes) in the family Narcinidae. They are bottom-dwelling cartilaginous fishes with large, rounded pectoral fin discs and long tails. They can produce an electric discharge
Electric discharge
Electric discharge describes any flow of electric charge through a gas, liquid or solid. Electric discharges include:*Electric glow discharge*Electric arc*Electrostatic discharge*Electric discharge in gases*Leader *Partial discharge...
for defense, from which their scientific name is derived (Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
narke, meaning "paralysis").
Members of this family are commonly known as the numbfishes, and are found almost worldwide in warm temperate and tropical continental and continental insular waters. They are strictly marine and are absent from river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s and lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s. They occur in sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es, muddy enclosed bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s, estuaries, off coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s and river mouths, and on the upper continental slope to a depth of 1,071 meters.
Description
Small to medium-sized rays, adult numbfishes range from 15 to 66 cm long, though most are less than 50 cm. They have oval, rounded, or shovelShovel
A shovel is a tool for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore. Shovels are extremely common tools that are used extensively in agriculture, construction, and gardening....
-shaped pectoral discs and stout tails of equal or longer length. The snout is moderately elongated, rounded or rounded-angular, differing from the narkids in being supported by broad rostral cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
s. The mouth is straight, with stout, elongated, and highly protrusible jaws and a prominent groove around its periphery. The nostril
Nostril
A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation...
s are just forward of the mouth and connected to it by a broad groove; the nasal flaps are short but merged into a broad nasal curtain that overlaps the mouth. The teeth are small have a single moderate cusp; the teeth and tooth bands are exposed when the mouth is closed (except in Diplobatis). There are two prominent dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s of roughly equal size, and a large caudal fin.
Numbfishes vary in color from whitish, yellowish, brownish, grey-brown, greenish, reddish, or black above, either plain or with small to large spots, blotches, bars or lines, sometimes forming complex eye-shaped spots or ocelli on the pectoral fins. They are usually white underneath, or black in deep-water species. The large, kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
-shaped electric organs are at the base of the pectoral fins and visible through the skin.
Biology and ecology
Numbfishes are slow-swimming bottom-dwellers that feed on small fishFish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es and invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s off the bottom; their protrusible jaws aid in removing prey from the substrate. They can generate a moderate shock if disturbed and contact is made with the electric organs; the electrical discharges of narcinids have been measured at 8-37 volt
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
s, much less than the electric rays of the genus Torpedo
Torpedo (genus)
Torpedo is a genus of rays, commonly known as electric rays, torpedo rays, or torpedoes. It is the sole genus of the family Torpedinidae. They are slow-moving bottom-dwellers capable of generating electricity as a defense and feeding mechanism...
. All species are ovoviviparous, with eggs hatching inside the mother.
Species
- Genus BenthobatisBenthobatisBenthobatis is a genus of fish in the Narcinidae family.It contains the following species:* Benthobatis kreffti Rincón, Stehmann & Vooren, 2001 * Benthobatis marcida Bean & Weed, 1909...
AlcockAlfred William AlcockAlfred William Alcock was a British physician naturalist and carcinologist.Alcock was the son of a sea-captain, John Alcock in Bombay, India who retired to live in Blackheath...
, 1898- Benthobatis kreffti Rincón, Stehmann & Vooren, 2001 (Brazilian blind electric ray)
- Benthobatis marcida BeanTarleton Hoffman BeanTarleton Hoffman Bean was an American ichthyologist, born at Bainbridge, Pennsylvania on 8 October 1846. He died in Albany, New York on 28 December 1916.-FAMILY AND EDUCATION :...
& Weed, 1909 (Blind torpedo) - Benthobatis moresbyi AlcockAlfred William AlcockAlfred William Alcock was a British physician naturalist and carcinologist.Alcock was the son of a sea-captain, John Alcock in Bombay, India who retired to live in Blackheath...
, 1898 (Dark blind ray) - Benthobatis yangi Carvalho, Compagno & Ebert, 2003 (Taiwanese blind electric ray)
- Genus DiplobatisDiplobatisDiplobatis is a genus of electric rays in the family Narcinidae.-Species:* Diplobatis colombiensis Fechhelm & McEachran, 1984 * Diplobatis guamachensis Martín Salazar, 1957...
BigelowHenry Bryant BigelowHenry Bryant Bigelow was an American oceanographer and marine biologist.After graduating from Harvard in 1901, he began working with famed ichthyologist Alexander Agassiz. Bigelow accompanied Agassiz on several major marine science expeditions including one aboard the Albatross in 1907...
& SchroederWilliam Charles SchroederWilliam Charles Schroeder was an American ichthyologist. He was born on Staten Island, New York. He, along with his lifelong colleague Henry Bryant Bigelow, made substantial contributions to the knowledge of the fish fauna of the western North Atlantic...
, 1948- Diplobatis colombiensis Fechhelm & McEachran, 1984 (Colombian electric ray)
- Diplobatis guamachensis Martín Salazar, 1957 (Brownband numbfish)
- Diplobatis ommata (D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& GilbertCharles Henry GilbertCharles Henry Gilbert was a pioneer ichthyologist and fishery biologist of particular significance to natural history of the western United States. He collected and studied fishes from Central America north to Alaska and described many new species...
, 1890) (Ocellated electric ray) - Diplobatis pictus G. Palmer, 1950 (Painted electric ray)
- Genus DiscopygeDiscopygeThe genus Discopyge, the apron rays is a small genus of fish in the family Narcinidae. It currently contains two species:* Discopyge castelloi Menni, Rincón & M. L. Garcia, 2008* Discopyge tschudii Heckel, 1846...
HeckelJohann Jakob HeckelJohann Jakob Heckel was an Austrian taxidermist, zoologist, and ichthyologist from Mannheim.Though not a formally trained zoologist he worked his way up through the ranks to eventually become the director of the Fish Collection at the Naturhistorisches Museum in Vienna...
, 1846- Discopyge castelloi Menni, Rincón & M. L. Garcia, 2008
- Discopyge tschudii HeckelJohann Jakob HeckelJohann Jakob Heckel was an Austrian taxidermist, zoologist, and ichthyologist from Mannheim.Though not a formally trained zoologist he worked his way up through the ranks to eventually become the director of the Fish Collection at the Naturhistorisches Museum in Vienna...
, 1846 (Apron ray)
- Genus NarcineNarcineNarcine is a genus of small electric rays in the family Narcinidae.-Description:Narcine species have a rounded pectoral fin disc and two dorsal fins, the first usually smaller than the second and placed behind the pelvic fin bases. The tail is longer than the disc and has a lateral fold...
HenleFriedrich Gustav Jakob HenleFriedrich Gustav Jakob Henle was a German physician, pathologist and anatomist. He is credited with the discovery of the loop of Henle in the kidney. His essay "On Miasma and Contagia" was an early argument for the germ theory of disease...
, 1834- Narcine atzi Carvalho & Randall, 2003
- Narcine bancroftii (E. Griffith & C. H. SmithCharles Hamilton SmithLieutenant-Colonel Charles Hamilton Smith was an English artist, naturalist, antiquary, illustrator, soldier and spy.-Military service:...
, 1834) (Lesser electric ray) - Narcine brasiliensis (OlfersIgnaz von OlfersIgnaz Franz Werner Maria von Olfers was a German naturalist, historian and diplomat. Olfers was born in Münster. In 1816 he travelled to Brazil as a diplomat....
, 1831) (Brazilian electric ray) - Narcine brevilabiata Bessednov, 1966 (Shortlip electric ray)
- Narcine brunnea AnnandaleNelson AnnandaleThomas Nelson Annandale CIE was a Scottish zoologist, entomologist and anthropologist.The eldest son of Thomas Annandale, the regius professor of clinical surgery at the University of Edinburgh, Nelson was educated at Rugby School, Balliol College, Oxford, and the University of Edinburgh.Annandale...
, 1909 (Brown numbfish) - Narcine entemedor D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& StarksEdwin Chapin StarksEdwin Chapin Starks was an ichthyologist most associated with Stanford University. He was known as an authority on the osteology of fish. He also did studies of fish of the Puget Sound. Additionally his wife and daughter were both involved in either science or natural history....
, 1895 (Giant electric ray) - Narcine insolita Carvalho, Séret & Compagno, 2002
- Narcine lasti Carvalho & Séret, 2002
- Narcine leoparda Carvalho, 2001
- Narcine lingula RichardsonJohn Richardson (naturalist)Sir John Richardson was a Scottish naval surgeon, naturalist and arctic explorer.Richardson was born at Dumfries. He studied medicine at Edinburgh University, and became a surgeon in the navy in 1807. He traveled with John Franklin in search of the Northwest Passage on the Coppermine Expedition of...
, 1846 (Chinese numbfish) - Narcine maculata (ShawGeorge ShawGeorge Shaw was an English botanist and zoologist.Shaw was born at Bierton, Buckinghamshire and was educated at Magdalen Hall, Oxford, receiving his M.A. in 1772. He took up the profession of medical practitioner. In 1786 he became the assistant lecturer in botany at Oxford University...
, 1804) (Darkfinned numbfish) - Narcine nelsoni Carvalho, 2008 (Eastern Numbfish)
- Narcine oculifera Carvalho, Compagno & Mee, 2002
- Narcine ornata Carvalho, 2008
- Narcine prodorsalis Bessednov, 1966 (Tonkin numbfish)
- Narcine rierai (Lloris & Rucabado, 1991) (Slender electric ray)
- Narcine tasmaniensis RichardsonJohn Richardson (naturalist)Sir John Richardson was a Scottish naval surgeon, naturalist and arctic explorer.Richardson was born at Dumfries. He studied medicine at Edinburgh University, and became a surgeon in the navy in 1807. He traveled with John Franklin in search of the Northwest Passage on the Coppermine Expedition of...
, 1841 (Tasmanian numbfish) - Narcine timlei (BlochMarcus Elieser BlochMarcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
& SchneiderJohann Gottlob SchneiderJohann Gottlob Theaenus Schneider was a German classicist and naturalist.-Biography:Schneider was born at Collm in Saxony...
, 1801) (Blackspotted numbfish) - Narcine vermiculatus Breder, 1928 (Vermiculate electric ray)
- Narcine westraliensis McKay, 1966 (Banded numbfish)