Main identification features
- disc: soft, flat, round, thick edges
- electric organs - sides of head
- 1st dorsal fin greater than 2nd dorsal fin
- mouth not tubular
- tail fin triangular
This family is closely related to the electric rays (Narcinidae). Both groups are characterized by the presence of a pair of well developed kidney-shaped electric organs that are externally visible on either side of the head. These organs can discharge up to 45 volts and are used for defense or to stun prey. Both families have a roundish, soft, flaccid disc that is rather thick around the margin. The best means of separating the two families is the difference in size of the two dorsal fins: those of narcinids are roughly equal in size, whereas the first dorsal fin of torpedinids is significantly larger than the second dorsal. In addition torpedinids have a larger mouth that does not protract into a short tube as it does in narcinids.
Torpedo rays inhabit most tropical and temperate seas, usually in depths less than 100 m, but some may occur down to at least 360 m. They are relatively inactive, soft-bottom dwellers that frequently cover themselves with sand or mud. Their diet consists of small bottom living invertebrates and fishes. They are viviparous without a placenta; the young closely resemble their parents at birth.
The family, which is found areas worldwide tropical to warm temperate, contains a two genera with twenty species. Two subtropical species are endemic to the eastern Pacific, one of which occurs in our region.
- Béarez, P., 1996., Lista de los Peces Marinos del Ecuador Continental., Revista de Biologia Tropical, 44:731-741.
- Chirichigno, N., 1963., Nuevas especies de "Rayas" para la fauna del Perú., Servicio de Pesqueria Perú, Servicio de Divulgación Cientica, 20:1-13.
- Compagno, L.J.V., 1999., Checklist of living elasmobranchs. In Hamlett W.C. (ed.) Sharks, skates, and rays: the biology of elasmobranch fishes., The John Hopkins University Press:471-498.
- Jimenez-Prado, P., Béarez, P., 2004., Peces marinos del Ecuador continental / Marine fishes of continental Ecuador., SIMBIOE/NAZCA/IFEA tomo 1 y 2.
- Lopez , M. I. and Bussing, W. A., 1982., Lista provisional de los peces marinos de la Costa Rica., Revista de Biologia Tropical, 30(1):5-26.
- Nelson, J.S., 1984., Fishes of the World (Third edition)., John Wiley and Sons:523pp.
- Parin , and Kotlyar,., 1985., Electric rays of genus Torpedo in the open waters of the southeastern Pacific Ocean., Journal Ichthyology (English translation of Voprosy Ikhtiologie), 25:1-12.
- Smith-Vaniz, W. F., 1997., Five new species of jawfishes (Opistognathus: Opistognathidae) from the Western Atlantic Ocean., Bull. Mar. Sci., 60:1074-1128.
I thank Ashley MacDonald and John Pickering, University of Georgia, for technical support in building this page.
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