Potamotrygon leopoldi

The Xingu River ray, white-blotched river stingray, or polka-dot stingray (Potamotrygon leopoldi) is a species of freshwater fish in the family Potamotrygonidae. It is endemic to the Xingu River basin in Brazil and prefers rocky bottoms. It is sometimes kept in aquaria. P. leopoldi reaches up to 40 cm (16 in) in disc width, 75 cm (30 in) in total length and 20 kg (44 lb) in weight. Females grow larger than males. It is closely related to the similar P. henlei from the Tocantins River basin and P. albimaculata from the Tapajós River basin. Compared to P. henlei, P. leopoldi is deeper black above and its underparts are mostly brownish-dusky (large white center to underparts of P. henlei). Compared to P. albimaculata, P. leopoldi has fewer and larger yellowish-white spots above.