51-418: See text The electric rays are a group of rays , flattened cartilaginous fish with enlarged pectoral fins , composing the order Torpediniformes / t ɔːr ˈ p ɛ d ɪ n ɪ f ɔːr m iː z / . They are known for being capable of producing an electric discharge , ranging from 8 to 220 volts , depending on species, used to stun prey and for defense. There are 69 species in four families. Perhaps
102-616: A gestation period of one year. The electric shock of this species can be quite severe and painful, though it is not fatal. Because of its electrogenic properties, the Atlantic torpedo was used in medicine by the Ancient Greeks and Romans and became the namesake of the naval weapon . Prior to the 19th century, its liver oil was used as lamp fuel, but it is no longer of any economic value. The International Union for Conservation of Nature (IUCN) has listed this species as Least Concern; it
153-804: A 2011 study significantly reevaluated the phylogeny of batoids, using nuclear and mitochondrial DNA from 37 taxa , representing almost all recognized families and all of the traditional four major lineages. This is a far more numerous and diverse set of sample taxa than in any previous study, producing findings reflected in the cladogram below. Holocephali (incl. Chimaera ) [REDACTED] Selachimorpha (Sharks) [REDACTED] Rajiformes (Skates) [REDACTED] Platyrhinidae (Thornbacks) Torpediniformes (Electric rays) [REDACTED] "Guitarfishes 1" ( Trygonorrhinidae ) [REDACTED] "Guitarfishes 2" (incl. Pristidae (Sawfishes)) [REDACTED] Zanobatidae (Panrays) Myliobatoidei (Stingrays) [REDACTED] This study strongly confirmed
204-452: A 2021 study in Nature , the number of oceanic sharks and rays has declined globally by 71% over the preceding 50 years, jeopardising "the health of entire ocean ecosystems as well as food security for some of the world's poorest countries". Overfishing has increased the global extinction risk of these species to the point where three-quarters are now threatened with extinction. This is notably
255-570: A family, the Narkidae. The torpedinids feed on large prey, which are stunned using their electric organs and swallowed whole, while the narcinids specialize on small prey on or in the bottom substrate. Both groups use electricity for defense, but it is unclear whether the narcinids use electricity in feeding. Eschmeyer's Catalog of Fishes lists classifies the following families in the Torpediniformes: Batoid Batomorphi
306-399: A few species, like manta rays , live in the open sea, and only a few live in freshwater, while some batoids can live in brackish bays and estuaries. Most batoids have developed heavy, rounded teeth for crushing the shells of bottom-dwelling species such as snails , clams , oysters , crustaceans , and some fish , depending on the species. Manta rays feed on plankton . Batoids belong to
357-634: A larger size than males. The Atlantic torpedo is widely distributed in cool waters on both sides of the Atlantic Ocean . In the east, it is found from northern Scotland to the Gulf of Guinea , including the entire Mediterranean Sea (but not the Black Sea ), the Azores , and Madeira , as well as from Namibia to western South Africa . In the west, it occurs from southern Nova Scotia to Venezuela and Brazil . It
408-451: A manner similar to the way the torpedo fish stuns with electricity. Scribonius Largus , a Roman physician, recorded the use of torpedo fish for treatment of headaches and gout in his Compositiones Medicae of 46 AD. In the 1770s the electric organs of the torpedo ray were the subject of Royal Society papers by John Walsh , and John Hunter . These appear to have influenced the thinking of Luigi Galvani and Alessandro Volta –
459-418: A nearly circular pectoral fin disc 1.2 times as wide as it is long, with a thick and nearly straight front margin. The eyes are small and are followed by much larger spiracles, which do not have papillae on their inner rims. The nostrils are close to the mouth; there is a flap of skin between them three times as wide as long, with a sinuous rear margin. The mouth is wide and arched, with prominent furrows at
510-555: A parallel circuit, whereas freshwater batteries are arranged in series. This allows freshwater rays to transmit discharges of higher voltage, as freshwater cannot conduct electricity as well as saltwater. With such a battery, an electric ray may electrocute larger prey with a voltage of between 8 volts in some narcinids to 220 volts in Torpedo nobiliana , the Atlantic torpedo. The 60 or so species of electric rays are grouped into 12 genera and two families. The Narkinae are sometimes elevated to
561-403: A ventrally located mouth and can considerably protrude their upper jaw (palatoquadrate cartilage) away from the cranium to capture prey. The jaws have euhyostylic type suspension, which relies completely on the hyomandibular cartilages for support. Bottom-dwelling batoids breathe by taking water in through the spiracles, rather than through the mouth as most fish do, and passing it outward through
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#1732855835708612-720: A well-developed caudal fin . The body is thick and flabby, with soft loose skin with no dermal denticles or thorns. A pair of kidney -shaped electric organs are at the base of the pectoral fins. The snout is broad, large in the Narcinidae, but reduced in all other families. The mouth, nostrils , and five pairs of gill slits are underneath the disc. Electric rays are found from shallow coastal waters down to at least 1,000 m (3,300 ft) deep. They are sluggish and slow-moving, propelling themselves with their tails, not by using their pectoral fins as other rays do. They feed on invertebrates and small fish. They lie in wait for prey below
663-405: A womb but without involvement of a placenta. The eggs of oviparous skates are laid in leathery egg cases that are commonly known as mermaid's purses and which often wash up empty on beaches in areas where skates are common. Capture-induced premature birth and abortion (collectively called capture-induced parturition) occurs frequently in sharks and rays when fished. Capture-induced parturition
714-452: Is caught unintentionally by commercial and recreational fishers , but the impact of these activities on its population is unknown. The first scientific description of the Atlantic torpedo was published in 1835 by French naturalist Charles Lucien Bonaparte , in his principal work Iconografia della Fauna Italica . Sixteen specimens were designated as the syntypes . The assignment of the southern African "great torpedo" to this species
765-531: Is a clade of cartilaginous fishes , commonly known as rays , this taxon is also known as the superorder Batoidea , but the 5th edition of Fishes of the World classifies it as the division Batomorphi. They and their close relatives, the sharks , compose the subclass Elasmobranchii . Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to
816-585: Is a species of electric ray in the family Torpedinidae . It is found in the Atlantic Ocean , from Nova Scotia to Brazil in the west and from Scotland to West Africa and off southern Africa in the east, occurring at depths of up to 800 m (2,600 ft), and in the Mediterranean Sea. Younger individuals generally inhabit shallower, sandy or muddy habitats , whereas adults are more pelagic in nature and frequent open water. Up to 1.8 m (6 ft) long and weighing 90 kg (200 lb),
867-406: Is a plain dark brown to gray, sometimes with a few diffuse spots, and darkening at the fin margins. The underside is white, with dark fin margins. The largest of the electric rays, the Atlantic torpedo can measure 1.8 m (6 ft) long and weigh 90 kg (200 lb). However, a length of 0.6–1.5 m (2.0–4.9 ft) and weight of 30 lb (14 kg) is more typical. Females attain
918-485: Is generally discarded or cut up for bait. The International Union for Conservation of Nature (IUCN) assesses the Atlantic torpedo as Least Concern; it could be negatively affected by fishing mortality, though specific data on catch rates and population trends are lacking, as well as by the degradation of coral reefs that are important to juveniles. Its slow reproductive rate would limit its capacity to recover from population depletion. Various electric fishes , including
969-561: Is provisional. Another type of electric ray found in the Indian Ocean off Mozambique may also belong to T. nobiliana . The Atlantic torpedo is placed in the genus Tetronarce , which differs from the other genus in the family Torpedinidae , Torpedo , in having generally plain coloration and smooth-margined spiracles . Other common names include Atlantic electric ray, Atlantic New British torpedo, black torpedo, crampfish, electric ray, numbfish, or torpedo. The Atlantic torpedo has
1020-613: Is rare in the North Sea and the Mediterranean and south of North Carolina . The genus Tetronarce is represented by a single species in the Mediterranean Sea, easy to identify with its characteristic dark blue pattern. Juvenile Atlantic torpedoes are primarily bottom-dwelling and usually found at depths of 10–50 m (33–164 ft) over sandy or muddy flats, or near coral reefs . As they mature, they become more pelagic in habits, and adults are often encountered swimming in
1071-489: Is rarely considered in fisheries management despite being shown to occur in at least 12% of live bearing sharks and rays (88 species to date). Most species live on the sea floor, in a variety of geographical regions – mainly in coastal waters, although some live in deep waters to at least 3,000 metres (9,800 ft). Most batoids have a cosmopolitan distribution , preferring tropical and subtropical marine environments, although there are temperate and cold-water species. Only
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#17328558357081122-525: The Jurassic . The oldest confirmed ray is Antiquaobatis , from the Pliensbachian of Germany . The clade is represented today by sharks , sawfish , rays and skates . Molecular evidence refutes the hypothesis that skates and rays are derived sharks. The monophyly of the skates , the stingrays , and the electric rays has long been generally accepted. Along with Rhinopristiformes , these comprise
1173-553: The Trygonorrhinidae , while the latter contains the remainder of Rhinopristiformes (the families Glaucostegidae , Pristidae , Rhinidae , and Rhinobatidae ). In addition, while traditional phylogenies often find electric rays to be the basalmost batoids, followed by the Rhinopristiformes, this analysis finds a polytomy between skates, electric rays, and thornbacks at the base of Batoidea, with weak support for skates being
1224-399: The stomach of one individual, and another contained a summer flounder ( Paralichthys dentatus ) 37 cm (15 in) long. This ray has been known to kill fish much larger than it can eat. The Atlantic torpedo is aplacental viviparous : the developing embryos are sustained by yolk , which is later supplemented by protein and fat -enriched histotroph ("uterine milk") produced by
1275-628: The Atlantic torpedo include the tapeworms Calyptrobothrium occidentale and C. minus , Grillotia microthrix , Monorygma sp., and Phyllobothrium gracile , the monogeneans Amphibdella flabolineata and Amphibdelloides maccallumi , and the copepod Eudactylina rachelae . Some accounts suggest that this ray may be able to survive out of water for up to a day. The diet of the Atlantic torpedo consists mainly of bony fishes , including flatfishes , salmon , eels , and mullet , though it has also been known to take small catsharks and crustaceans . Captive rays have been observed lying still on
1326-446: The Atlantic torpedo is capable of generating up to 220 volts of electricity to subdue its prey or defend itself against predators. Its diet consists mainly of bony fishes , though it also feeds on small sharks and crustaceans . It is an aplacental viviparous species, wherein the developing embryos are nourished by yolk and later maternally provided histotroph ("uterine milk"). Females give birth to up to 60 young following
1377-429: The Atlantic torpedo is the largest known electric ray. Like other members of its genus, it has an almost circular pectoral fin disk with a nearly straight leading margin, and a robust tail with a large triangular caudal fin . Distinctive characteristics include its uniform dark color, smooth-rimmed spiracles (paired respiratory openings behind the eyes), and two dorsal fins of unequal size. Solitary and nocturnal ,
1428-518: The Atlantic torpedo, were used in medicine during the classical era . In the 1st century, Roman physician Scribonius Largus wrote of the application of live "dark torpedo" to patients afflicted with gout or chronic headaches . In 1800, the Atlantic torpedo became the namesake for the naval weapon when American inventor Robert Fulton began using the word "torpedo" to describe bombs that submarines could attach to ships (although these early devices were more akin to modern-day mines ). Before
1479-466: The actual most basal lineage, followed by a clade uniting the electric rays and thornbacks. The Mesozoic Sclerorhynchoidea are basal or incertae sedis ; they show features of the Rajiformes but have snouts resembling those of sawfishes. However, evidence indicates they are probably the sister group to sawfishes. Eschmeyer's Catalog of Fishes classigies the rays as follows: According to
1530-578: The ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling those of today's chondrichthyans date at least as far back as the Ordovician , with the oldest unambiguous fossils of cartilaginous fish dating from the middle Devonian . A clade within this diverse family, the Neoselachii , emerged by the Triassic , with the best-understood neoselachian fossils dating from
1581-471: The best known members are those of the genus Torpedo . The torpedo undersea weapon is named after it. The name comes from the Latin torpere , 'to be stiffened or paralyzed', from the effect on someone who touches the fish. Electric rays have a rounded pectoral disc with two moderately large rounded-angular (not pointed or hooked) dorsal fins (reduced in some Narcinidae ), and a stout muscular tail with
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1632-568: The bottom and "pouncing" on fish that pass in front of them. At the moment of contact, the ray traps the prey against its body or the bottom by curling its pectoral fin disc around it, while delivering strong electric shocks. This strategy allows the sluggish ray to capture relatively fast-moving fish. Once subdued, the prey is maneuvered to the mouth with rippling motions of the disc and swallowed whole, head-first. The ray's highly distensible jaws allow surprisingly large prey to be ingested: an intact salmon weighing 2 kg (4 lb) has been found in
1683-867: The case in the Mediterranean Sea - most impacted by unregulated fishing - where a recent international survey of the Mediterranean Science Commission concluded that only 38 species of rays and skates still subsisted. All sharks and rays are cartilaginous fish, contrasting with bony fishes . Many rays are adapted for feeding on the bottom. Guitarfishes are somewhat between sharks and rays, displaying characteristics of both (though they are classified as rays). Torpedo nobiliana Torpedo emarginata M'Coy, 1841 Torpedo hebetans Lowe, 1838 Torpedo nigra Guichenot, 1850 Torpedo nobiliana Bonaparte, 1835 Torpedo occidentalis Storer, 1843 Torpedo walshii Thompson, 1856 The Atlantic torpedo ( Tetronarce nobiliana )
1734-420: The corners. The teeth are pointed and increase in number with age, ranging from 38 rows in juveniles to 66 rows in adults; the first several series of teeth are functional. The gill slits are small, with the first and fifth pairs shorter than the others. The pelvic fins are rounded and slightly overlapped by the disc at the front. The first dorsal fin is triangular with a rounded apex, originating in front of
1785-424: The curtain of skin between the nostrils has not yet developed; on the other hand, the eyes, spiracles, dorsal fins, and tail have reached adult proportions. Newborn rays measure 17–25 cm (6.7–9.8 in) long, and still have the anterior notches in the disc. Males and females reach sexual maturity at lengths of 55 cm (22 in) and 90 cm (35 in) respectively. Though seldom life-threatening,
1836-417: The electric discharge of an Atlantic torpedo is quite severe and may be enough to knock a person unconscious. However, a greater danger to divers is the disorientation that follows the shock. The Atlantic torpedo is of no commercial value, as its meat is flabby and tasteless. It is caught incidentally by commercial and recreational fisheries in bottom trawls and on hook-and-line. When caught at sea, it
1887-514: The electric organ occur in a series, or train, of closely spaced pulses each lasting around 0.03 seconds. Trains contain on average 12 pulses, but trains of over 100 pulses have been recorded. The ray regularly emits pulses even without an obvious external stimulus. Solitary in nature, the Atlantic torpedo is often seen resting on or half-buried in the substrate during the day, becoming more active at night. Large and well-defended from attack, it seldom falls prey to other animals. Known parasites of
1938-408: The founders of electrophysiology and electrochemistry. Henry Cavendish proposed that electric rays use electricity; he built an artificial ray consisting of fish shaped Leyden jars to successfully mimic their behaviour in 1773. The torpedo fish, or electric ray, appears continuously in premodern natural histories as a magical creature, and its ability to numb fishermen without seeming to touch them
1989-662: The four traditionally accepted major batoid lineages, as in Nelson's 2006 Fishes of the World . However, the exact phylogeny of the major batoid lineages, internally and with respect to one another, has been subject to diverse treatments. The following cladogram is based on a comprehensive morphological assessment of batoid phylogeny published in 2004: Holocephali (incl. Chimaera ) [REDACTED] Selachimorpha (Sharks) [REDACTED] Torpediniformes [REDACTED] Rhinopristiformes [REDACTED] Rajiformes [REDACTED] Myliobatiformes [REDACTED] However,
2040-507: The gills. Batoids reproduce in a number of ways. As is characteristic of elasmobranchs, batoids undergo internal fertilization . Internal fertilization is advantageous to batoids as it conserves sperm, does not expose eggs to consumption by predators, and ensures that all the energy involved in reproduction is retained and not lost to the environment. All skates and some rays are oviparous (egg laying) while other rays are ovoviviparous , meaning that they give birth to young which develop in
2091-464: The head, and gill slits that are placed on their ventral surfaces. Batoids are flat-bodied, and, like sharks, are cartilaginous fish, meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batoids have five ventral slot-like body openings called gill slits that lead from the gills , but the Hexatrygonidae have six. Batoid gill slits lie under the pectoral fins on
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2142-437: The lower to the upper surface of the body. The nerves that signal the organ to discharge branch repeatedly, then attach to the lower side of each plaque in the batteries. These are composed of hexagonal columns, closely packed in a honeycomb formation. Each column consists of 500 to more than 1000 plaques of modified striated muscle, adapted from the branchial (gill arch) muscles. In marine fish , these batteries are connected as
2193-402: The mother. Females have two functional ovaries and uteruses , and a possibly biennial reproductive cycle. After a year-long gestation period , females bear up to 60 pups during the summer; the litter size increases with the size of the female. When the embryo is 14 cm (5.5 in) long, it has a pair of deep notches at the front of the disc marking the origin of the pectoral fins, and
2244-476: The open ocean. This species has been recorded from the surface to a depth of 800 m (2,600 ft); in the Mediterranean, it is most common at depths of 200–500 m (660–1,640 ft). It is said to make long migratory movements . Like other members of its family, the Atlantic torpedo is capable of generating a powerful electric shock from a pair of kidney-shaped electric organs in its disc, for both attack and defense. These organs comprise one-sixth of
2295-448: The pelvic fin insertions. The second dorsal fin is only one-half to two-thirds as large as the first; the distance between the dorsal fins is less than the length of the first dorsal fin base. The stout tail comprises about one-third of the total length, terminating in a caudal fin shaped like an equilateral triangle with slightly convex margins. The skin is soft and completely devoid of dermal denticles ( scales ). The dorsal coloration
2346-413: The ray's total weight and contain around half a million jelly-filled "electric plates" arranged in an average of 1,025–1,083 vertical hexagonal columns (visible beneath the skin). These columns essentially act as batteries connected in parallel , enabling a large Atlantic torpedo to produce up to a kilowatt of electricity at 170–220 volts , provided that it is well-fed and rested. The discharges from
2397-413: The sand or other substrate, using their electricity to stun and capture it. The electrogenic properties of electric rays have been known since antiquity, although their nature was not understood. The ancient Greeks used electric rays to numb the pain of childbirth and operations. In his dialogue Meno , Plato has the character Meno accuse Socrates of "stunning" people with his puzzling questions, in
2448-419: The traditionally accepted internal monophyly of skates, stingrays, and electric rays. It also recovered panrays as sister to the stingrays, as older morphological analyses had suggested. However, it found the Rhinopristiformes, including the sawfishes and various "guitarfishes", to be paraphyletic , comprising two distinct clades. Referred to as "Guitarfishes 1" and "Guitarfishes 2", the former contains only
2499-401: The underside, whereas a shark's are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the guitarfishes and sawfishes , while most sharks have a spindle-shaped body. Many species of batoid have developed their pectoral fins into broad flat wing-like appendages. The anal fin is absent. The eyes and spiracles are located on top of the head. Batoids have
2550-487: The widespread introduction of kerosene in the 19th century, the liver oil of this species was regarded as of equal quality to sperm whale ( Physeter macrocephalus ) oil for use in lamps. Before the 1950s, its oil was also used in small quantities by fishermen in the United States as a treatment for muscle and stomach cramps , as well as to lubricate farm machinery. Along with several other species of electric rays,
2601-422: Was a significant source of evidence for the belief in occult qualities in nature during the ages before the discovery of electricity as an explanatory mode. The electric rays have specialised electric organs . Many species of rays and skates outside the family have electric organs in the tail; however, the electric ray has two large kidney-shaped electric organs on each side of its head, where current passes from
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