Electric ray

Source: Wikipedia, the free encyclopedia.
This article is about the fish. For the fictional energy weapon, see raygun.

Electric rays
Temporal range: Eocene–Recent[1]
Marbled electric ray
(Torpedo marmorata)
Lesser electric ray
(Narcine bancroftii)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Torpediniformes
F. de Buen
, 1926
Families

The electric rays are a group of

producing an electric discharge, ranging from 8 to 220 volts, depending on species, used to stun prey and for defense.[2]
There are 69 species in four families.

Perhaps 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.[3]

Description

Electric rays have a rounded pectoral disc with two moderately large rounded-angular (not pointed or hooked)

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.[2][4]

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 the sand or other substrate, using their electricity to stun and capture it.[5]

Relationship to humans

History of research

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.[2] In his dialogue Meno, Plato has the character Meno accuse Socrates of "stunning" people with his puzzling questions, in a manner similar to the way the torpedo fish stuns with electricity.[6] Scribonius Largus, a Roman physician, recorded the use of torpedo fish for treatment of headaches and gout in his Compositiones Medicae of 46 AD.[7]

In the 1770s the electric organs of the torpedo ray were the subject of Royal Society papers by John Walsh,[8] and John Hunter.[9][10] These appear to have influenced the thinking of Luigi Galvani and Alessandro Volta – the founders of electrophysiology and electrochemistry.[11][12] 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.[13]

In folklore

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 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.[14]

Bioelectricity

Further information: Electric fish
Position of the two electric organs
Diagram of structure of electric organs and stacked electrocytes

The electric rays have specialised

Torpedo nobiliana, the Atlantic torpedo.[2][18]

Systematics

The 60 or so species of electric rays are grouped into 12 genera and two families.[19] The Narkinae are sometimes elevated to 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.[20]

See also

References

  1. ^ Froese, Rainer, and Daniel Pauly, eds. (2011). "Torpediniformes" in FishBase. February 2011 version.
  2. ^ a b c d e f Martin, R. Aidan. "Electric Rays". ReefQuest Centre for Shark Research. Archived from the original on 15 October 2008. Retrieved 12 October 2008.
  3. ISBN 0-00-458641-7
    .
  4. ISBN 0-8018-6048-2
    .
  5. ISBN 0-12-547665-5
    .
  6. ^ Wikisource:Meno
  7. ISBN 978-0-387-28275-6
    .
  8. ^ Walsh, John (1773). "On the Electric Property of the Torpedo: in a Letter to Benjamin Franklin". Philosophical Transactions of the Royal Society of London (64): 461–480.
  9. ^ Hunter, John (1773). "Anatomical Observations on the Torpedo". Philosophical Transactions of the Royal Society of London (63): 481–489.
  10. ^ Hunter, John (1775). "An account of the Gymnotus electricus". Philosophical Transactions of the Royal Society of London (65): 395–407.
  11. PMID 4895861
    .
  12. ^ Edwards, Paul (10 November 2021). "A Correction to the Record of Early Electrophysiology Research on the 250 th An- niversary of a Historic Expedition to Île de Ré". HAL open-access archive. Retrieved 6 May 2022.
  13. ^ Al-Khalili, Jim. "Shock and Awe: The Story of Electricity". BBC. Retrieved 9 June 2022.
  14. PMID 11622951
    .
  15. ^ Bigelow, H. B.; Schroeder, W. C. (1953). Fishes of the Western North Atlantic, Part 2. Sears Foundation for Marine Research, Yale University. pp. 80–104.
  16. ISBN 0-520-22149-4
    .
  17. ISBN 978-3-540-23735-8
    . Retrieved 2012-03-25.
  18. ISBN 0-7614-7266-5
    .
  19. ISBN 0-471-25031-7
    .
  20. ^ Compagno, Leonard J.V. and Heemstra, Phillip C. (May 2007) "Electrolux addisoni, a new genus and species of electric ray from the east coast of South Africa (Rajiformes: Torpedinoidei: Narkidae), with a review of torpedinoid taxonomy". Smithiana, Publications in Aquatic Biodiversity, Bulletin 7: 15-49. Retrieved on October 22, 2008.
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