Porcupine River Stingray

The porcupine river stingray (Potamotrygon histrix, sometimes incorrectly modified to Potamotrygon hystrix) is a species of river stingray in the family Potamotrygonidae, the type of the Potamotrygon genus. It is found in the basins of the Paraná and Paraguay River basins in South America. Most chemical weathering of minerals seems to take place in the upland drainage basins rather than on the floodplains, and most major solutes display conservative mixing in the river-floodplain system. The population...