Electric eel: Difference between revisions

This is a good article. Click here for more information.
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
better ref for air-breathing
→‎Behaviour: gas exchange
Line 136: Line 136:
Electric eels use their high frequency–sensitive tuberous receptors, distributed in patches over the body, for hunting other Gymnotiformes.<ref name=Fishbase/> Electric eels can control their prey's nervous systems and muscles via electrical pulses, keeping prey from escaping or forcing it to move so they can locate it.<ref>{{cite journal |last1=Catania |first1=K. C. |title=The shocking predatory strike of the electric eel |journal=[[Science (journal)|Science]] |volume=346 |issue=6214 |pages=1231–4 |date=December 2014 |pmid=25477462 |doi=10.1126/science.1260807 |bibcode=2014Sci...346.1231C |s2cid=14371418 }}</ref> The fish have been observed to leap from the water to deliver electric shocks to animals that might pose a threat, such as horses wading through rivers.<ref>{{cite journal |last=Catania |first=K. C. |title=Leaping eels electrify threats, supporting Humboldt's account of a battle with horses |journal=[[PNAS]] |volume=113 |issue=25 |pages=6979–84 |date=June 2016 |pmid=27274074 |pmc=4922196 |doi=10.1073/pnas.1604009113 |doi-access=free }}</ref> The shocks from leaping electric eels are sufficient to cause intense pain to horses and to humans.<ref>{{cite journal |last1=Catania |first1=K. C. |title=Power Transfer to a Human during an Electric Eel's Shocking Leap |journal=[[Current Biology]] |volume=27 |issue=18 |pages=2887–2891.e2 |date=September 2017 |pmid=28918950 |doi=10.1016/j.cub.2017.08.034 |doi-access=free }}</ref>
Electric eels use their high frequency–sensitive tuberous receptors, distributed in patches over the body, for hunting other Gymnotiformes.<ref name=Fishbase/> Electric eels can control their prey's nervous systems and muscles via electrical pulses, keeping prey from escaping or forcing it to move so they can locate it.<ref>{{cite journal |last1=Catania |first1=K. C. |title=The shocking predatory strike of the electric eel |journal=[[Science (journal)|Science]] |volume=346 |issue=6214 |pages=1231–4 |date=December 2014 |pmid=25477462 |doi=10.1126/science.1260807 |bibcode=2014Sci...346.1231C |s2cid=14371418 }}</ref> The fish have been observed to leap from the water to deliver electric shocks to animals that might pose a threat, such as horses wading through rivers.<ref>{{cite journal |last=Catania |first=K. C. |title=Leaping eels electrify threats, supporting Humboldt's account of a battle with horses |journal=[[PNAS]] |volume=113 |issue=25 |pages=6979–84 |date=June 2016 |pmid=27274074 |pmc=4922196 |doi=10.1073/pnas.1604009113 |doi-access=free }}</ref> The shocks from leaping electric eels are sufficient to cause intense pain to horses and to humans.<ref>{{cite journal |last1=Catania |first1=K. C. |title=Power Transfer to a Human during an Electric Eel's Shocking Leap |journal=[[Current Biology]] |volume=27 |issue=18 |pages=2887–2891.e2 |date=September 2017 |pmid=28918950 |doi=10.1016/j.cub.2017.08.034 |doi-access=free }}</ref>


''Electrophorus'' breathe air using the buccal cavity. This enables it to live in a variety of wet habitats including streams, swamps, and pools.<!--pp=719–720--><ref name="Kramer Lindsey Moodie Stevens 1978">{{cite journal |last1=Kramer |first1=D. L. |last2=Lindsey |first2=C. C. |last3=Moodie |first3=G. E. E. |last4=Stevens |first4=E. D. |title=The fishes and the aquatic environment of the central Amazon basin, with particular reference to respiratory patterns |journal=Canadian Journal of Zoology |date=1978 |volume=56 |pages=717-729 |url=https://www.researchgate.net/profile/Don-Stevens/publication/237980361_The_fishes_and_the_aquatic_environment_of_the_central_Amazon_basin_with_particular_reference_to_respiratory_patterns/links/00b7d537f720f4aa7e000000/The-fishes-and-the-aquatic-environment-of-the-central-Amazon-basin-with-particular-reference-to-respiratory-patterns.pdf}}</ref>
''Electrophorus'' breathe air using the [[Buccal space|buccal cavity]]. This enables it to live in wet habitats subject to varying oxygen levels including streams, swamps, and pools.<!--pp=719–720--><ref name="Kramer Lindsey Moodie Stevens 1978">{{cite journal |last1=Kramer |first1=D. L. |last2=Lindsey |first2=C. C. |last3=Moodie |first3=G. E. E. |last4=Stevens |first4=E. D. |title=The fishes and the aquatic environment of the central Amazon basin, with particular reference to respiratory patterns |journal=Canadian Journal of Zoology |date=1978 |volume=56 |pages=717-729 |url=https://www.researchgate.net/profile/Don-Stevens/publication/237980361_The_fishes_and_the_aquatic_environment_of_the_central_Amazon_basin_with_particular_reference_to_respiratory_patterns/links/00b7d537f720f4aa7e000000/The-fishes-and-the-aquatic-environment-of-the-central-Amazon-basin-with-particular-reference-to-respiratory-patterns.pdf}}</ref> The buccal cavity is lined with a mucosa which has a rich blood supply, enabling gas exchange between the air and the blood. The fish takes in air through the mouth, holds it in the buccal cavity, and expels it through the [[Operculum (fish)|opercular openings]] at the sides of the head.<ref name="Johansen Lenfant Schmidt-Nielsen Petersen 1968 pp. 137–163">{{cite journal | last=Johansen | first=Kjell | last2=Lenfant | first2=Claude | last3=Schmidt-Nielsen | first3=Knut |author3-link=Knut Schmidt-Nielsen | last4=Petersen | first4=Jorge A. | title=Gas exchange and control of breathing in the electric eel, Electrophorus electricus | journal=Zeitschrift für Vergleichende Physiologie | volume=61 | issue=2 | year=1968 | doi=10.1007/bf00341112 | pages=137–163}}</ref>


It had been thought that electric eels were solitary, but ''E. voltai'' sometimes hunts in packs. Groups of the animals were observed to coordinate their activities after targeting a shoal of [[tetra (fish)|tetras]], then herding them and launching joint strikes on the closely-packed fish.<ref>{{cite journal |last1=Bastos |first1=Douglas A. |last2=Zuanon |first2=Jansen |last3=Rapp Py‐Daniel |first3=Lúcia |last4=Santana |first4=Carlos David |title=Social predation in electric eels |journal=[[Ecology and Evolution]] |volume=11 |issue=3 |date=14 January 2021 |doi=10.1002/ece3.7121 |pages=1088–1092 |pmid=33598115 |pmc=7863634 }}</ref> The species mainly eats fish, in particular the armoured catfish ''[[Megalechis thoracata]]''.<ref name="Oliveira 2019"/>
It had been thought that electric eels were solitary, but ''E. voltai'' sometimes hunts in packs. Groups of the animals were observed to coordinate their activities after targeting a shoal of [[tetra (fish)|tetras]], then herding them and launching joint strikes on the closely-packed fish.<ref>{{cite journal |last1=Bastos |first1=Douglas A. |last2=Zuanon |first2=Jansen |last3=Rapp Py‐Daniel |first3=Lúcia |last4=Santana |first4=Carlos David |title=Social predation in electric eels |journal=[[Ecology and Evolution]] |volume=11 |issue=3 |date=14 January 2021 |doi=10.1002/ece3.7121 |pages=1088–1092 |pmid=33598115 |pmc=7863634 }}</ref> The species mainly eats fish, in particular the armoured catfish ''[[Megalechis thoracata]]''.<ref name="Oliveira 2019"/>

Revision as of 12:44, 16 July 2022

For other uses, see Electric eel (disambiguation).

Electric eel
An electric eel in an aquarium
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gymnotiformes
Family: Gymnotidae
Genus: Electrophorus
T. N. Gill, 1864
Type species
Electrophorus electricus
(Linnaeus, 1766)
Species

Electrophorus electricus
Electrophorus varii
Electrophorus voltai

The electric eels are a genus, Electrophorus, of neotropical freshwater fish from South America in the family Gymnotidae. They are known for their ability to stun their prey by generating electricity, delivering shocks at up to 600 volts. Despite their name, electric eels are not closely related to the true eels (Anguilliformes) but are members of the electroreceptive neotropical knifefish order (Gymnotiformes), which is more closely related to the catfish. For over two centuries, the genus was believed to be monotypic, containing only Electrophorus electricus, until the unexpected discovery in 2019 of two additional species.

The fish's electrical capabilities were first studied by Hugh Williamson and John Hunter in 1775, contributing to the 1800 invention of the electric battery. Three pairs of electric organs are arranged along the body, enabling the fish to generate both low voltage discharges for electrolocation, and high voltage discharges to stun prey or to defend themselves. Tuberous electroreceptors are distributed around the body in the skin.

Phylogeny

External relationships

Electric eels form a clade of strongly electric fishes within the order Gymnotiformes, the South American Knifefishes. Most of these are weakly electric, capable of active electrolocation but not of delivering shocks. They are not closely related to the Anguilliformes, the true eels.[1] Their relationships were analysed by sequencing their mitochondrial genomes in 2019. This shows that contrary to earlier ideas, the Apteronotidae and Sternopygidae are not sister taxa.[2] Actively electrolocating fish are marked on the phylogenetic tree with a small yellow lightning flash . Fish able to deliver electric shocks are marked with a red lightning flash . There are other electric fishes in other families (not shown).[3][4][5]

Otophysi

Siluriformes (catfish) (some )

Gymnotiformes

Apteronotidae (ghost knifefishes)

Hypopomidae (bluntnose knifefishes)

Rhamphichthyidae (sand knifefishes)

Gymnotidae

Gymnotus (banded knifefishes)

Electrophorus

Sternopygidae (glass knifefishes)

Characoidei (piranhas, tetras, and allies)

Species

There are three described species:[1]

X-rays and photographs of the heads of the three species of electric eel
Differences between the three species of Electrophorus, namely E. electricus, E. voltai, and E. varii

Description

Electrophorus species have long, stout eel-like bodies, being somewhat cylindrical at the front but more flattened towards the end. E. electricus can reach 2 m (6 ft 7 in) in length, and 20 kg (44 lb) in weight. The mouth is at the front of the snout, and opening upwards. Electric eels have a smooth brown to black skin with a yellow or red underbelly and no scales. There is no clear boundary between the tail fin and the anal fin, which extends the whole length of the body and has over 400 bony rays. Electrophorus differs from other South American knifefishes in having thick skin, large sensory openings along the sides, an "oral respiratory organ" covered in blood vessels, differently shaped the bones of the skull, and eight radials in each pectoral fin. The body cavity reaches into the tip of the tail. As the fish grow, they continually add more vertebrae to their spinal column.[1][7] Electrophorus species are sexually dimorphic, males becoming reproductively active at 1.2 m (3 ft 11 in) in length and growing larger than females; females start to reproduce at a body length of around 70 cm (28 in). Aquarium specimens have reached an age of at least 20 years.[7]

Distribution and habitat

The three species have different distributions in the northern part of South America. E. electricus is northern, confined to the Guiana Shield, while E. voltai is southern, ranging from the Brazilian shield northwards; both species live in upland waters. E. varii is central, largely in the lowland intercratonic basin.[1] All live on muddy river bottoms and sometimes swamps, favouring areas in deep shade. They can tolerate water low in oxygen as they swim to the surface to breathe air.[8]

The lowland region of E. varii is a variable environment, with habitats ranging from streams through grassland and ravines to ponds, and large changes in water level between the wet and dry seasons. The species reproduces in the dry season, the adults surviving through this period by air-breathing, and the young through prolonged parental care lasting four months. The two upland species, living in fast-flowing rivers, appear to make less use of parental care.[9]

Map of South America showing distribution of the three species of electric eel
Map of the northern part of South America showing distribution of specimens of the three species of Electrophorus: E. electricus (1, red); E. voltai (2, blue); E. varii (3, yellow).[1]

Research history

Taxonomy

Original description by Carl Linnaeus in the 12th edition of Systema Naturae, 1766, as Gymnotus electricus. The text states that the fish is from the rivers of Surinam, that it causes painful shocks, and that there are small pits around the head.[10]

The genus has been reclassified several times. When the species now defined as Electrophorus electricus was originally described by Carl Linnaeus in 1766, he used the name Gymnotus electricus, placing it in the same genus as Gymnotus carapo (banded knifefish) which he had described several years earlier.[10][11]

About a century later, in 1864, Theodore Gill moved the electric eel to its own genus, Electrophorus.[11] In 1872, Gill decided that the electric eel was sufficiently distinct to have its own family, Electrophoridae,[12] but in 2017 the genus was merged back into the family Gymnotidae, alongside Gymnotus.[13][14][15]

In 2019, C. David de Santana et al. suggested the division of E. electricus into three species based on DNA divergence, ecology and habitat, anatomy and physiology, and electrical ability. The proposed three species are E. electricus, E. voltai sp. nov., and E. varii sp. nov.[1]

Early electrical research

Artist's impression of Alexander von Humboldt's experience in 1800 of hunting electric eels using a herd of horses, as told in his Journey to the Equinoctial Regions of the New Continent, published in 1859[16]

In 1775, Hugh Williamson presented a paper "Experiments and observations on the Gymnotus Electricus, or electric eel" at the Royal Society. He reported a series of experiments, such as "7. In order to discover whether the eel killed those fish by an emission of the same [electrical] fluid with which he affected my hand when I had touched him, I put my hand into the water, at some distance from the eel; another cat-fish was thrown into the water; the eel swam up to it ... [and] gave it a shock, by which it instantly turned up its belly, and continued motionless; at that very instant I felt such a sensation in the joints of my fingers as in experiment 4." and "12. Instead of put­ting my hand into the water, at a distance from the eel, as in the last experiment, I touched its tail, so as not to offend it, while my assistant touched its head more roughly; we both received a severe shock."[17] The "torpedo" (the electric ray) was studied at the same time by John Walsh;[18] both fish were studied by the surgeon and anatomist John Hunter.[18][19]

In 1800, Alexander von Humboldt joined a group of indigenous people who went fishing with horses, some thirty of which they chased into the water. The pounding of the horses' hooves, he noted, drove the fish, up to five feet (1.5 metres) long out of the mud and prompted them to attack, rising out of the water and using their electricity to shock the horses. He saw two horses stunned by the shocks and then drowned. The electric eels, having given many shocks, "now require long rest and plenty of nourishment to replace the loss of galvanic power they have suffered", "swam timidly to the bank of the pond", and were easily caught using small harpoons on ropes.[16]

Hunter noted that "Gymnotus Electricus ... appears very much like an eel ... but it has none of the specific properties of that fish."[19] He observed that there were "two pair of these [electric] organs, a larger [the main organ] and a smaller [Hunter's organ]; one being placed on each side", and that they occupied "perhaps ... more than one-third of the whole animal [by volume]".[19] He described the structure of the organs (stacks of electrocytes) as "extremely simple and regular, consisting of two parts; viz. flat partitions or septa, and cross divisions between them." He measured the electrocytes as 1/17 of an inch thick (1.5 mm) in the main organ, and 1/56 of an inch thick (0.5 mm) in Hunter's organ.[19]

  • Painting of John Hunter, 18th century anatomist
    The surgeon John Hunter dissected an electric eel in 1775.
  • Engraving of an electric eel, 1775
    Hunter's "Gymnotus Electricus", underside and upperside, 1775.
    The figure occupied four pages of his paper for the Royal Society.[19]
  • Engraving of cross-section of electric eel
    Cross-section:
    C=Back muscles, H=main organ, I=Hunter's organ

The studies by Williamson, Walsh, and Hunter appear to have influenced the thinking of Luigi Galvani and Alessandro Volta – the founders of electrophysiology and electrochemistry.[18][20]

In 1839, the chemist Michael Faraday extensively tested the electrical properties of an electric eel imported from Suriname. For a span of four months, he measured the electrical impulses produced by the animal by pressing shaped copper paddles and saddles against the specimen. Through this method, he determined and quantified the direction and magnitude of electric current, and proved that the animal's impulses were electrical by observing sparks and deflections on a galvanometer. He observed the electric eel increasing the shock by coiling about its prey, the prey fish "representing a diameter" across the coil. He likened the quantity of electric charge released by the fish to "the electricity of a Leyden battery of fifteen jars, containing 3500 square inches of glass coated on both sides, charged to its highest degree"[21]

In 1877, the German zoologist Carl Sachs published his research on the fish, including his discovery of what is now called Sachs' organ.[22][23]

  • Diagram of experimental setup showing fish in tank
    Michael Faraday's diagram of the setup for his "Experimental Researches in Electricity" on the electric eel, 1838. The fish is in a circular wooden tub in shallow water. He noted that the strongest shock was obtained when both hands or a pair of copper paddles were placed in the water, at positions 1 and 8, i.e. by the head and tail of the fish.[21]
  • Carl Sachs' illustration of his discovery of Sachs's organ in the electric eel, 1877
    Carl Sachs' illustration of his discovery of Sachs's organ in the electric eel, 1877

Electrophysiology

Further information: Electric fish and Electroreception and electrogenesis

Electric eels have three pairs of electric organs, arranged longitudinally: the main organ, Hunter's organ, and Sachs' organ. These organs give electric eels the ability to generate two types of electric organ discharges: low voltage and high voltage. The organs are made of electrocytes, modified from muscle cells, lined up so a current of ions can flow through them, and stacked so each one adds to a potential difference.[24] The maximum discharge from the main organ is at least 600 volts, making electric eels the most powerful of all electric fishes.[25]

As well as generating electric discharges, Electrophorus can locate its prey using electroreceptors derived from the lateral line organ in the head. The lateral line itself is mechanosensory, enabling Electrophorus to sense water movements created by animals nearby. The lateral line canals are beneath the skin, but their position is visible as lines of pores on the head.[26]

Diagram of the locations of the electric organs of an electric eel.
Anatomy of electric eel's three electric organs. The main organ produces a powerful shock used in hunting; Sachs's organ produces small discharges used in electrolocation; and Hunter's organ produces middling discharges that may prepare the fish for the main organ discharge.[23]

When an electric eel identifies prey, its brain sends a signal to the main organ. This opens ion channels, allowing sodium to flow through, reversing the polarity momentarily. By causing a sudden difference in electric potential, it generates an electric current in a manner similar to a battery, in which stacked plates each produce an electric potential difference of 0.15 volts.[24] Sachs' organ is used for electrolocation; its discharge is of nearly 10 volts at a frequency of around 25 Hz. The main organ, supported by Hunter's organ in some way, is used to stun prey or to deter predators; they can emit signals at rates of several hundred hertz. Electric eels can concentrate the discharge to stun prey more effectively by curling up and making contact with the prey at two points along the body.[27][25]

It remains unclear why electric eels have three electric organs but basically produce two types of discharge, to electrolocate or to stun. In 2021, Jun Xu and colleagues state that Hunter's organ produces a third type of discharge at a middle voltage of 38.5 to 56.5 volts. Their measurements indicate that this is produced just once, for less than 2 milliseconds, after the low-voltage discharge of Sachs's organ and before the high-voltage discharge of the main organ. They believe, contrary to Catania 2014, that this is insufficient to stimulate a response from the prey, so they suggest it may have the function of co-ordination within the electric eel's body, perhaps by balancing the electrical charge, but state that more research is needed.[23]

The main electrical organ and the strong-voltage section of Hunter's organ are rich in the protein calmodulin which is involved in controlling the flow of calcium ions and hence electrical activity,[28] and in sodium potassium ATPase, an ion pump used to create a potential difference across cell membranes.[29][30]

Behaviour

Electric eels use their high frequency–sensitive tuberous receptors, distributed in patches over the body, for hunting other Gymnotiformes.[27] Electric eels can control their prey's nervous systems and muscles via electrical pulses, keeping prey from escaping or forcing it to move so they can locate it.[31] The fish have been observed to leap from the water to deliver electric shocks to animals that might pose a threat, such as horses wading through rivers.[32] The shocks from leaping electric eels are sufficient to cause intense pain to horses and to humans.[33]

Electrophorus breathe air using the buccal cavity. This enables it to live in wet habitats subject to varying oxygen levels including streams, swamps, and pools.[34] The buccal cavity is lined with a mucosa which has a rich blood supply, enabling gas exchange between the air and the blood. The fish takes in air through the mouth, holds it in the buccal cavity, and expels it through the opercular openings at the sides of the head.[35]

It had been thought that electric eels were solitary, but E. voltai sometimes hunts in packs. Groups of the animals were observed to coordinate their activities after targeting a shoal of tetras, then herding them and launching joint strikes on the closely-packed fish.[36] The species mainly eats fish, in particular the armoured catfish Megalechis thoracata.[6] The other new species, E. varii, is also a fish predator; it preys especially on Callichthyidae (armoured catfishes) and Cichlidae (cichlids).[37]

References

  1. ^ a b c d e f g de Santana, C. David; Crampton, William G. R.; et al. (10 September 2019). "Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator". Nature Communications. 10 (1): 4000. Bibcode:2019NatCo..10.4000D. doi:10.1038/s41467-019-11690-z. PMC 6736962. PMID 31506444.
  2. ^ Elbassiouny, Ahmed A.; Schott, Ryan K.; Waddell, Joseph C.; et al. (1 January 2016). "Mitochondrial genomes of the South American electric knifefishes (Order Gymnotiformes)". Mitochondrial DNA Part B. 1 (1): 401–403. doi:10.1080/23802359.2016.1174090. PMC 7799549. PMID 33473497.
  3. ^ Bullock, Theodore H.; Bodznick, D. A.; Northcutt, R. G. (1983). "The phylogenetic distribution of electroreception: Evidence for convergent evolution of a primitive vertebrate sense modality" (PDF). Brain Research Reviews. 6 (1): 25–46. doi:10.1016/0165-0173(83)90003-6. hdl:2027.42/25137. PMID 6616267. S2CID 15603518.
  4. ^ Lavoué, Sébastien; Miya, Masaki; Arnegard, Matthew E.; Sullivan, John P.; Hopkins, Carl D.; Nishida, Mutsumi (14 May 2012). Murphy, William J. (ed.). "Comparable Ages for the Independent Origins of Electrogenesis in African and South American Weakly Electric Fishes". PLOS ONE. 7 (5): e36287. Bibcode:2012PLoSO...736287L. doi:10.1371/journal.pone.0036287. PMC 3351409. PMID 22606250.
  5. ^ Lavoué, Sébastien; Miya, Masaki; Arnegard, Matthew E.; Sullivan, John P.; Hopkins, Carl D.; Nishida, Mutsumi (14 May 2012). "Comparable Ages for the Independent Origins of Electrogenesis in African and South American Weakly Electric Fishes". PLOS ONE. 7 (5): e36287. Bibcode:2012PLoSO...736287L. doi:10.1371/journal.pone.0036287. PMC 3351409. PMID 22606250.
  6. ^ a b c d e Oliveira, Marcos S. B.; Mendes‐Júnior, Raimundo N. G.; Tavares‐Dias, Marcos (10 September 2019). "Diet composition of the electric eel Electrophorus voltai (Pisces: Gymnotidae) in the Brazilian Amazon region". Journal of Fish Biology. 97 (4): 1220–1223. doi:10.1111/jfb.14413. PMID 32463115. S2CID 218976160.
  7. ^ a b Albert, J. S. (2001). "Species diversity and phylogenetic systematics of American knifefishes (Gymnotiformes, Teleostei)". Miscellaneous Publications (190): 66. hdl:2027.42/56433.
  8. ^ "Electrophorus electricus: Electric eel". Animal Diversity Web. Retrieved 15 July 2022.
  9. ^ Bastos, Douglas Aviz (November 2020). História Natural de Poraquês (Electrophorus spp.), Gymnotiformes: Gymnotidae (in Portuguese). Manaus: Instituto Nacional de Pesquisas da Amazônia (PhD Thesis). pp. 10, 60, 63, and throughout. Abstracts in English.
  10. ^ a b Linnaeus, Carl (1766). Systema Naturae (in Latin) (12th ed.). Stockholm: Laurentius Salvius. pp. 427–428. OCLC 65020711.
  11. ^ a b Jordan, D. S. (1963). The Genera of Fishes and a Classification of Fishes. Stanford University Press. p. 330.
  12. ^ Van der Laan, Richard; Eschmeyer, William N.; Fricke, Ronald (11 November 2014). Zootaxa: Family-group names of Recent fishes. Auckland, New Zealand: Magnolia Press. p. 57. ISBN 978-1-77557-573-3.
  13. ^ Nelson, J. S.; Grande, T. C.; Wilson, M. V. (2016). Fishes of the World (5 ed.). John Wiley & Sons. ISBN 978-1118342336.
  14. ^ van der Sleen, P.; Albert, J. S., eds. (2017). Field Guide to the Fishes of the Amazon, Orinoco, and Guianas. Princeton University Press. pp. 330–334. ISBN 978-0691170749.
  15. ^ Ferraris, C. J., Jr; de Santana, C. D.; Vari, R. P. (2017). "Checklist of Gymnotiformes (Osteichthyes: Ostariophysi) and catalogue of primary types". Neotropical Ichthyology. 15 (1). doi:10.1590/1982-0224-20160067.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ^ a b von Humboldt, Alexander (1859). Alexander von Humboldt's Reise in die Aequinoctial-Gegenden des neuen Continents (in German). Vol. 1. Stuttgart: J. G. Cotta'scher Verlag. pp. 404–406.
  17. ^ Williamson, Hugh (1775). "Experiments and observations on the Gymnotus electricus, or electric eel". Philosophical Transactions of the Royal Society (65): 94–101.
  18. ^ a b c Edwards, Paul (10 November 2021). "A Correction to the Record of Early Electrophysiology Research on the 250th Anniversary of a Historic Expedition to Île de Ré". HAL open-access archive. Retrieved 6 May 2022.
  19. ^ a b c d e Hunter, John (1775). "An account of the Gymnotus electricus". Philosophical Transactions of the Royal Society of London (65): 395–407.
  20. ^ Alexander, Mauro (1969). "The role of the voltaic pile in the Galvani-Volta controversy concerning animal vs. metallic electricity". Journal of the History of Medicine and Allied Sciences. XXIV (2): 140–150. doi:10.1093/jhmas/xxiv.2.140. PMID 4895861.
  21. ^ a b Faraday, Michael (1839). "Experimental Researches in Electricity, Fifteenth Series". Philosophical Transactions of the Royal Society. 129: 1–12. doi:10.1098/rstl.1839.0002.
  22. ^ Sachs, Carl (1877). "Beobachtungen und versuche am südamerikanischen zitteraale (Gymnotus electricus)" [Observations and research on the South American electric eel (Gymnotus electricus)]. Archives of Anatomy and Physiology (in German): 66–95.
  23. ^ a b c Xu, Jun; Cui, Xiang; Zhang, Huiyuan (18 March 2021). "The third form electric organ discharge of electric eels". Scientific Reports. 11 (1): 6193. doi:10.1038/s41598-021-85715-3. PMC 7973543. PMID 33737620.
  24. ^ a b Xu, J.; Lavan, D. A. (November 2008). "Designing artificial cells to harness the biological ion concentration gradient". Nature Nanotechnology. 3 (11): 666–70. Bibcode:2008NatNa...3..666X. doi:10.1038/nnano.2008.274. PMC 2767210. PMID 18989332.
  25. ^ a b Catania, Kenneth C. (November 2015). "Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey". Current Biology. 25 (22): 2889–98. doi:10.1016/j.cub.2015.09.036. PMID 26521183.
  26. ^ Verçoza, Gabriel; Shibuya, Akemi; Bastos, Douglas A.; Zuanon, Jansen; Rapp Py-Daniel, Lúcia H. (2021). "Organization of the cephalic lateral-line canals in Electrophorus varii de Santana, Wosiacki, Crampton, Sabaj, Dillman, Mendes-Júnior & Castro e Castro, 2019 (Gymnotiformes: Gymnotidae)". Neotropical Ichthyology. 19 (2). doi:10.1590/1982-0224-2020-0075.
  27. ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2005). "Electrophorus electricus" in FishBase. December 2005 version.
  28. ^ Traeger, Lindsay L.; Sabat, Grzegorz; Barrett-Wilt, Gregory A.; et al. (July 2017). "A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel". Science Advances. 3 (7): e1700523. Bibcode:2017SciA....3E0523T. doi:10.1126/sciadv.1700523. PMC 5498108. PMID 28695212.
  29. ^ Ching, Biyun; Woo, Jia M.; Hiong, Kum C.; et al. (20 March 2015). "Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus". PLOS One. 10 (3): e0118352. Bibcode:2015PLoSO..1018352C. doi:10.1371/journal.pone.0118352. PMC 4368207. PMID 25793901.
  30. ^ Traeger, Lindsay L.; Sabat, Grzegorz; Barrett-Wilt, Gregory A.; Wells, Gregg B.; Sussman, Michael R. (7 July 2017). "A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel". Science Advances. 3 (7): e1700523. Bibcode:2017SciA....3E0523T. doi:10.1126/sciadv.1700523. PMC 5498108. PMID 28695212.
  31. ^ Catania, K. C. (December 2014). "The shocking predatory strike of the electric eel". Science. 346 (6214): 1231–4. Bibcode:2014Sci...346.1231C. doi:10.1126/science.1260807. PMID 25477462. S2CID 14371418.
  32. ^ Catania, K. C. (June 2016). "Leaping eels electrify threats, supporting Humboldt's account of a battle with horses". PNAS. 113 (25): 6979–84. doi:10.1073/pnas.1604009113. PMC 4922196. PMID 27274074.
  33. ^ Catania, K. C. (September 2017). "Power Transfer to a Human during an Electric Eel's Shocking Leap". Current Biology. 27 (18): 2887–2891.e2. doi:10.1016/j.cub.2017.08.034. PMID 28918950.
  34. ^ Kramer, D. L.; Lindsey, C. C.; Moodie, G. E. E.; Stevens, E. D. (1978). "The fishes and the aquatic environment of the central Amazon basin, with particular reference to respiratory patterns" (PDF). Canadian Journal of Zoology. 56: 717–729.
  35. ^ Johansen, Kjell; Lenfant, Claude; Schmidt-Nielsen, Knut; Petersen, Jorge A. (1968). "Gas exchange and control of breathing in the electric eel, Electrophorus electricus". Zeitschrift für Vergleichende Physiologie. 61 (2): 137–163. doi:10.1007/bf00341112.
  36. ^ Bastos, Douglas A.; Zuanon, Jansen; Rapp Py‐Daniel, Lúcia; Santana, Carlos David (14 January 2021). "Social predation in electric eels". Ecology and Evolution. 11 (3): 1088–1092. doi:10.1002/ece3.7121. PMC 7863634. PMID 33598115.
  37. ^ Mendes-Júnior, Raimundo Nonato Gomes; Sá-Oliveira, Júlio César; Vasconcelos, Huann Carllo Gentil; et al. (2020). "Feeding ecology of electric eel Electrophorus varii (Gymnotiformes: Gymnotidae) in the Curiaú River Basin, Eastern Amazon". Neotropical Ichthyology. 18 (3). FapUNIFESP (SciELO). doi:10.1590/1982-0224-2019-0132.
Wikimedia Commons has media related to Electrophorus.
Wikispecies has information related to Electrophorus electricus.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Electric_eel&oldid=1098565185"