Naked-back knifefish

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Naked-back knifefishes
Electric eel, Electrophorus electricus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Gymnotiformes Suborder: Gymnotoidei Family: Gymnotidae
Genera
Electrophorus Gymnotus See text for species.

The naked-back knifefishes are a family (Gymnotidae) of knifefishes that are found only in fresh waters of Central America and South America.^[1] All have organs adapted to the exploitation of bioelectricity. The family has 33 valid species in two genera.^[2] There are a number of undescribed species known in museum collections.

These fish are nocturnal and mostly occur in quiet waters from deep rivers to swamps. In strongly-flowing waters they may bury themselves.^[1]

[edit] Physical characteristics

Like the other gymnotiforms, Gymnotids have a classic knifefish body. The body is long and eel-like, the dorsal fin and pectoral fins are absent, and the anal fin is extremely long and used for movement.^[1]

The sole member of Electrophorus is the electric eel, which produces both strong (up to 600 V) and weak (<1 V) electric discharges, for use in predation and communication/navigation, respectively. The electric eel is the largest of the gymnotiform fishes, growing up to more than 2 m (7 feet) in length. Species of Gymnotus reach up to about 100 cm in length.^[2]

[edit] Species

There are 33 species in two genera:

• Genus Electrophorus
  • Electric eel, Electrophorus electricus (Linnaeus, 1766).
• Genus Gymnotus
  • Gymnotus anguillaris Hoedeman, 1962.
  • Gymnotus arapaima Albert & Crampton, 2001.
  • Gymnotus ardilai Maldonado-Ocampo & Albert, 2004.
  • Gymnotus bahianus Campos-da-Paz & Costa, 1996.
  • Banded knifefish, Gymnotus carapo Linnaeus, 1758.
  • Gymnotus cataniapo Mago-Leccia, 1994.
  • Gymnotus choco Albert, Crampton & Maldonado, 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 & Maldonado, 2003.
  • Gymnotus inaequilabiatus (Valenciennes, 1842).
  • Gymnotus javari Albert, Crampton & Hagedorn, 2003.
  • Gymnotus jonasi Albert & Crampton, 2001.
  • Spotted knifefish, Gymnotus maculosus Albert & Miller, 1995.
  • Gymnotus mamiraua Albert & Crampton, 2001.
  • Gymnotus melanopleura Albert & Crampton, 2001.
  • Gymnotus obscurus Crampton, Thorsen & Albert, 2005.
  • Gymnotus onca Albert & Crampton, 2001.
  • Gymnotus panamensis Albert & Crampton, 2003.
  • Gymnotus pantanal Fernandes, Albert, Daniel-Silva, 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 ucamara Crampton, Lovejoy & Albert, 2003.
  • Gymnotus varzea Crampton, Thorsen & Albert, 2005.

[edit] References

1. ^ ^{a b c} "Gymnotidae". FishBase. Ed. Ranier Froese and Daniel Pauly. Apr 2007 version. N.p.: FishBase, 2007.
2. ^ ^{a b} Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc.. ISBN 0471250317.