Gymnotus
| Banded knifefishes | |
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| Gymnotus inaequilabiatus | |
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| Genus: | Gymnotus Linnaeus, 1758
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| Species | |
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Gymnotus is the among the most species-rich group of electric knifefishes (Gymnotiformes) found widely in the Neotropics, including the Amazon. Some Gymnotus species live in the leaf litter and root tangles of river banks. Other species are specialized to live on floodplains within the rootmats of floating meadows. Several species are broadly adapted to live in both of these habitats. Gymnotus are nocturnal predators feeding on insects, crustaceans, and other fish. They generate weak electric fields used in locating objects, and also for communication in which the males court females using stereotyped electrical "songs".[citation needed]
Small scales are always present on this fish. The mouth is superior, meaning it is turned upwards. The anal fin terminates at a point near the tip of the tail. Species of Gymnotus reach up to about 100 cm in length. This is the most widespread genus of the order Gymnotiformes, extending from southern Mexico to Argentina. They also occur in Trinidad.[1]
Michael Faraday extensively tested the electrical properties of a gymnotus specimen, imported from Suriname. For a span of four months, Faraday carefully and humanely measured the electrical impulses produced by the animal by pressing shaped copper paddles and saddles against the specimen. Through this method, Faraday determined and quantified the direction and magnitude of electric current; and proved that the animal's impulses were in fact electrical by observing sparks and deflections on a galvanometer.[2]
Species
- Gymnotus anguillaris Hoedeman, 1962
- Gymnotus arapaima Albert & Crampton, 2001
- Gymnotus ardilai Maldenado-Ocampo & Albert, 2004
- Gymnotus bahianus Campos-da-Paz & W. J. E. M. Costa, 1996
- Gymnotus capanema Milhomem, Crampton, Pieczarka, Shetka, D. S. Silva & Nagamachi, 2012[3]
- Gymnotus carapo Linnaeus, 1758 (Banded knifefish)
- Gymnotus cataniapo Mago-Leccia, 1994
- Gymnotus chaviro Maxime & Albert, 2009
- Gymnotus chimarrao Cognato, Richer-de-Forges, Albert & Crampton, 2008[4]
- Gymnotus choco Albert, Crampton & Maldenado-Ocampo, 2003
- Gymnotus coatesi La Monte, 1935
- Gymnotus coropinae Hoedeman, 1962
- Gymnotus curupira Crampton, Thorsen & Albert, 2005
- Gymnotus cylindricus La Monte, 1935
- Gymnotus diamantinensis Campos-da-Paz, 2002
- Gymnotus esmeraldas Albert & Crampton, 2003
- Gymnotus henni Albert, Crampton & Maldenado-Ocampo, 2003
- Gymnotus inaequilabiatus (Valenciennes, 1842)
- Gymnotus javari Albert, Crampton & Hagedorn, 2003
- Gymnotus jonasi Albert & Crampton, 2001
- Gymnotus maculosus Albert & R. R. Miller, 1995 (Spotted knifefish)
- Gymnotus mamiraua Albert & Crampton, 2001
- Gymnotus melanopleura Albert & Crampton, 2001
- Gymnotus obscurus Crampton, Thorsen & Albert, 2005
- Gymnotus omarorum Richer-de-Forges, Crampton & Albert, 2009
- Gymnotus onca Albert & Crampton, 2001
- Gymnotus panamensis Albert & Crampton, 2003
- Gymnotus pantanal Fernandes, Albert, Daniel-Silva, C. E. Lopes, Crampton & Almeida-Toledo, 2005
- Gymnotus pantherinus (Steindachner, 1908)
- Gymnotus paraguensis Albert & Crampton, 2003
- Gymnotus pedanopterus Mago-Leccia, 1994
- Gymnotus stenoleucus Mago-Leccia, 1994
- Gymnotus sylvius Albert & Fernandes-Matioli, 1999
- Gymnotus tigre Albert & Crampton, 2003
- Gymnotus tiquie Maxime, F. C. T. Lima & Albert, 2011
- Gymnotus ucamara Crampton, Lovejoy & Albert, 2003
- Gymnotus varzea Crampton, Thorsen & Albert, 2005
References
- Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Gymnotus". FishBase. December 2011 version.
- ^ Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ Fifteenth Series, Experimental Researches in Electricity. Philosophical Transactions of the Royal Society. 1838.
- ^ Milhomem, S.S.R., Crampton, W.G.R., Pieczarka, J.C., Shetka, G.H., Silva, D.S. & Nagamachi, C.Y. (2012): Gymnotus capanema, a new species of electric knife fish (Gymnotiformes, Gymnotidae) from eastern Amazonia, with comments on an unusual karyotype. Journal of Fish Biology, doi:10.1111/j.1095-8649.2012.03219.x
- ^ Cognato; et al. "Gymnotus chimarrao, a new species of electric fish (Gymnotiformes: Gymnotidae) from Southern Brazil". Ichthyol. Explor. Freshwaters. 18: 375–382.
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