Xingu River ray Xingu River ray 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 in disc width, in total length and 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
Amazon River the northern slope of the valley. The drainage area of the Amazon basin above Óbidos city is about , and, below, only about (around 20%), exclusive of the of the Tocantins basin. The Tocantins River enters the southern portion of the Amazon delta. In the lower reaches of the river, the north bank consists of a series of steep, table-topped hills extending for about from opposite the mouth of the Xingu as far as Monte Alegre. These hills are cut down to a kind of terrace which lies between them and the river. On the south bank, above the Xingu,