Parana River Stingray: Potamotrygon schuhmacheri

Family: Potamotrygonidae

Common names

Parana River Stingray, Rosette Freshwater Stingray, Shuhmacher’s Stingray.

Binomial

Potamotrygon schuhmacheri.

Synonyms

Potamotrygon schuehmacheri, Potamotrygon schuemacheri.

Identification

A small freshwater stingray with a subcircular disc that is slightly longer than wide. Small, often indistinct lobe on tip of snout. Eyes relatively large and protruding. Spiracle trapezoid, length approximately 2x orbit length. Nostrils small. Mouth small with 5 oral papillae.
Disc well covered in small denticles; denticles largest towards centre of disc. Pelvic fin posterior margins approximately level with pectoral disc margin. Tail fairly broad-based, shorter than disc width, well-covered in denticles, with a single irregular row of tall, falcate thorns on centre line. Caudal stings positioned distally at end of tail.

Colour

Dorsum brown to greyish or olive brown, or light or golden brown reticulations often forming spiracle-sized irregular ‘rosettes’ and smaller irregular spots towards disc margin. Ventrum mostly greyish with white spots Tail dark posteriorly.

Size

Maximum disc width at least 35cm. Total length 45cm. Disc width at birth unknown.

Parana River Stingray, Potamotrygon shuhmacheri. Aka Rosette Freshwater Stingray or Shuhmacher's Stingray. Rio Salobra, Pantanal, Mato Grosso, Brazil.

Conservation Status

DATA DEFICIENT

Very little is known about the Parana River Stingray (Potamotrygon schumacheri). It is considered rare and has a patchy distribution, leaving it vulnerable to overfishing by subsistence fishermen. It is probably also collected for the aquarium trade.

Habitat

Tropical freshwater lakes and river systems.

Distribution

South America. The Parana river stingray has a fragmented distribution in the Parana-Paraguay basin where it is found mainly in the Paraná River and the Colastiné River, a branch of Paraná River (near Santa Fé), and Paraguay River (near Assunción). Recently found in the Rio Salobra in the southern Pantanal (personal obervation).

Reproduction

Viviparous. Largely unknown.

Diet

Diet unknown, but probably consists of insects, molluscs, crustaceans, and small fishes.

Behavior

Poorly known. In the Rio Salobra, the Parana River Stingray favoured narrow, darker channels (personal observation).

Reaction to divers

Fairly easy to approach with non-threatening movements. Will move away but easily followed.

Diving logistics

The only place I have found to photograph the Parana river stingray is in the Rio Salobra delta, west of Campo Grande in the Brazilian Pantanal. This is not a true delta but an area where the river splits into multiple channels. I encountered this species in early June.