CHONDRICHTHYS – the rays and sharks

  • Family: Potamotrygonidae
    This family of freshwater stingrays is confined to South American rivers flowing to the Atlantic or Caribbean and rivers in W. Africa. They are widely distributed in Amazonia, occuring in lakes, rivers and streams. They are bottom feeding omnivores which are ovoviviparous. The sting of these fish is extremely painful and the wound often becomes infected. The commonest genus is Potamotrygon and the distance across the fins can reach 1 m. The Amazon and its tributaries possibly hold 20 or more species; approximately 14 species have been described.

    These rays give birth to live young. At birth they measure about 6 cm across the wings and are already able to sting.

    There are 3 genera, Elipesurus, Paratrygon and Potamotrygon.
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    Dorsal view of an adult Potamotrygon hystrix caught in a varzea lake near Tefe. Note the long sting situated on the upper surface of the tail. This species appears to be widely distributed in both Black and white waters. It favors sandy bottoms although it is also caught in muddy varzea lakes.
    Dorsal view of an adult Potamotrygon hystrix caught in a varzea lake near Tefe. Note the long sting situated on the upper surface of the tail. This species appears to be widely distributed in both Black and white waters. It favours sandy bottoms although it is also caught in muddy varzea lakes.

    Ventral view of an adult Potamotrygon hystrix caught in a varzea lake near Tefe.
    Ventral view of an adult Potamotrygon hystrix caught in a varzea lake near Tefe.

    Dorsal view of an adult Potamotrygon motoro caught in a varzea channel near Tefe. This species is widely distributed in black and white waters and is frequently encountered in forest streams, like other stingrays it favours sandy substrates in relatively oxygen rich waters.
    Dorsal view of an adult Potamotrygon motoro caught in a varzea channel near Tefe. This species is widely distributed in black and white waters and is frequently encountered in forest streams, like other stingrays it favours sandy substrates in relatively oxygen rich waters.