Porcupine river stingray

8/12/2019

Photo by FishBase, IBAMA

We’re back to showcasing freshwater Chondrichthyans that are rays! Hooray! Are you really surprised?

The porcupine river stingray (Potamotrygon histrix, sometimes incorrectly known as Potamotrygon hystrix) is in the family ______. We’ve done this enough now: do you know it? Is it:

Glyphis
Potamotrygonidae
Galeocerdo

Did you choose 2? You’re correct! That’s in the Potamotrygon genus. Like others in this genus, they are found in South America. Specifically in the Paraná and Paraguay River basins. Like other freshwater rays, they are popular in the aquarium trade and prefer deep, sandy bottoms since they like to bury themselves to the point you just see their eyes. Similar to what they do in the wild! They are carnivorous but won’t turn on one another since they are not territorial.

Freshwater rays are known for being almost circular in shape, and the Porcupine river ray is no different! They grow up to 40 cm (16 in) in disc width (DW) and 15 kg (33 lb) in weight. The top part of them is covered with denticles (sharp scales) and they are a brown colour with mottled patterns on the dorso. They are one of our favorite rays because they have a pink underbelly!

Like other stingrays, they have a venomous barb at the base of their tail that is covered with toxic mucus. Ouch! The IUCN has assessed them as Data Deficient (DD).