Torpedinidae

The family Torpedinidae contains 22 species of electric rays or torpedoes, flat cartilaginous fishes that produce electricity as a defense and feeding mechanism. They are slow-moving bottom-dwellers.

The largest species is the Atlantic torpedo, ''Tetronarce nobiliana'', which can grow to a weight of and deliver a 220-volt electric shock. Electric rays have patches of modified muscle cells called electroplaques that make up an electric organ. These generate an electric gradient, similar to the normal electric potential across most cell membranes, but amplified greatly by its concentration into a very small area. The electricity can be stored in the tissues, which act as a battery. The shock can be discharged in pulses. A ray can emit a shock into the body of a prey animal to stun it and make it easier to capture and eat, or into the body of a predator. Tissue from electric rays is often used in neurobiological research because of its unique properties.

Torpedo rays are flat like other rays, disc-shaped, with caudal fins that vary in length. Their mouths and gill slits are located on their undersides. Males have claspers near the base of the tail. Females are ovoviviparous, meaning they form eggs but do not lay them. The young emerge from the eggs within the body of the female, and she gives live birth. The young are called ''pups''.

The naval weapon known as the torpedo was named after this genus, whose own name has the same Latin origin as the English word ''torpid,'' meaning "sluggish" or "lethargic", presumably the sensations one would feel after experiencing the ray's electric shock.

Species

There are 22 species in 2 genera:Carvalho, M.R. de. (2015): Torpedinidae. In : Heemstra, P.C., Heemstra, E. & Ebert, D.A. (Eds.), Coastal Fishes of the Western Indian Ocean. ''Vol. 1. South African Institute for Aquatic Biodiversity, Grahamstown, South Africa. In press.''

* Genus '' Tetronarce'' T. N. Gill, 1862
**'' Tetronarce californica'' Ayres, 1855 (Pacific electric ray)
**'' Tetronarce cowleyi'' Ebert, D. L. Haas & M. R. de Carvalho, 2015 (Cowley's torpedo ray) Ebert, D.A., Haas, D.L. & de Carvalho, M.R. (2015): ''Tetronarce cowleyi'', sp. nov., a new species of electric ray from southern Africa (Chondrichthyes: Torpediniformes: Torpedinidae). ''Zootaxa, 3936 (2): 237–250.''
**'' Tetronarce fairchildi'' F. W. Hutton, 1872 (New Zealand torpedo)
**'' Tetronarce formosa'' D. L. Haas & Ebert, 2006 (Taiwan torpedo)
**'' Tetronarce macneilli'' Whitley, 1932 (Shorttail torpedo)
**'' Tetronarce nobiliana'' Bonaparte, 1835 (Atlantic torpedo)
**'' Tetronarce puelcha'' Lahille, 1926 (Argentine torpedo)
**'' Tetronarce tokionis'' S. Tanaka (I), 1908 (Trapezoid torpedo)
**'' Tetronarce tremens'' F. de Buen, 1959 (Chilean torpedo)
* Genus ''Torpedo'' Forsskål, 1775Welter-Schultes, F.W., V. Feuerstein (2008) Nomenclatural notes on ''Torpedo'' (Chondrichthyes: Torpedinidae) and some other early established fish taxa (Actinopterygii: Molidae, Eleginopidae and Citharinidae). Species, Phylogeny and Evolution 1(3):141-145.
**'' Torpedo adenensis'' M. R. de Carvalho, Stehmann & Manilo, 2002 (Aden Gulf torpedo)
**'' Torpedo alexandrinsis'' Mazhar, 1987 (Alexandrine torpedo)
**'' Torpedo andersoni'' Bullis, 1962 (Florida torpedo)
**'' Torpedo bauchotae'' Cadenat, Capapé & Desoutter, 1978 (Rosette torpedo)
**'' Torpedo fuscomaculata'' W. K. H. Peters, 1855 (Black-spotted torpedo)
**'' Torpedo mackayana'' Metzelaar, 1919 (Ringed torpedo)
**'' Torpedo marmorata'' A. Risso, 1810 (Marbled electric ray)
**'' Torpedo microdiscus'' Parin & Kotlyar, 1985 (Smalldisk torpedo)
**'' Torpedo panthera'' Olfers, 1831 (Leopard torpedo)
**'' Torpedo semipelagica'' Parin & Kotlyar, 1985 (Semipelagic torpedo)
**'' Torpedo sinuspersici'' Olfers, 1831 (Variable torpedo or Gulf torpedo)
**'' Torpedo suessii'' Steindachner, 1898
**'' Torpedo torpedo'' (Linnaeus, 1758) (Common torpedo)

References

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Torpediniformes
Live-bearing fish
Ray families
Taxa named by Charles Lucien Bonaparte