Potamotrygonidae

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River stingrays
Ocellate river stingray, Potamotrygon motoro
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Subclass: Elasmobranchii Order: Rajiformes Family: Potamotrygonidae
Genera
Paratrygon Plesiotrygon Potamotrygon Trygon See text for species.

River stingrays are neotropical freshwater fishes of the Potamotrygonidae family (order Rajiformes).

They are native to eastern South America, living in rivers that drain into the Caribbean, and into the Atlantic as far south as the Río de la Plata in Argentina. Generally, each species is native to a single river basin.

River stingrays are almost circular in shape, and range in size from Potamotrygon schuhmacheri, which reaches 25 cm in diameter, to the ocellate river stingray, Potamotrygon motoro, which grows up to a metre in diameter. The dorsal surface is covered with denticles (sharp tooth-like scales).

They have a poisonous caudal sting, and are one of the most feared freshwater fishes in the neotropical region, sometimes more feared than piranhas and electric eels. However, they are not dangerous unless stepped on or otherwise threatened.

River stingrays are the only family of batoids to be restricted to fresh water habitats.

[edit] Species

There are nineteen species in four genera:

• Genus Paratrygon
  • Discus ray, Paratrygon aiereba (Müller & Henle, 1841).
• Genus Plesiotrygon
  • Long-tailed river stingray, Plesiotrygon iwamae Rosa, Castello & Thorson, 1987.
• Genus Potamotrygon
  • Short-tailed river stingray, Potamotrygon brachyura (Günther, 1880).
  • Vermiculate river stingray, Potamotrygon castexi Castello & Yagolkowski, 1969.
  • Thorny river stingray, Potamotrygon constellata (Vaillant, 1880).
  • Largespot river stingray, Potamotrygon falkneri Castex & Maciel, 1963.
  • Bigtooth river stingray, Potamotrygon henlei (Castelnau, 1855).
  • Porcupine river stingray, Potamotrygon hystrix (Müller & Henle, 1834).
  • White-blotched river stingray, Potamotrygon leopoldi Castex & Castello, 1970.
  • Magdalena river stingray, Potamotrygon magdalenae (Duméril, 1865).
  • Ocellate river stingray, Potamotrygon motoro (Müller & Henle, 1841).
  • Red-blotched river stingray, Potamotrygon ocellata (Engelhardt, 1912).
  • Smooth back river stingray, Potamotrygon orbignyi (Günther, 1880).
  • Rosette river stingray, Potamotrygon schroederi Fernández-Yépez, 1957.
  • Potamotrygon schuhmacheri Castex, 1964.
  • Raspy river stingray, Potamotrygon scobina Garman, 1913.
  • Parnaiba river stingray, Potamotrygon signata Garman, 1913.
  • Maracaibo river stingray, Potamotrygon yepezi Castex & Castello, 1970.
• Genus Trygon
  • Trygon garrapa Jardine, 1843.

[edit] References

• "Potamotrygonidae". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2006 version. N.p.: FishBase, 2006.