Reticulated Freshwater Stingray: Potamotrygon falkneri

Family: Potamotrygonidae
Common name(s)

Reticulated Freshwater Stingray, Paraná Freshwater Stingray, Largespot River Stingray.

Identification

A medium-sized freshwater stingray with a thin oval disc that is slightly longer than wide. Very small lobe visible on tip of snout. Head relatively flat and broad. Eyes small. Spiracle length approximately 2x eye length. Nostrils thin. Nasal curtain fringed. Mouth small with 5 oral papillae.
Disc sparsely covered in denticles; more densely grouped towards centre of disc. Pelvic fin posterior margins slightly posterior to (or level with) disc. Tail relatively narrow, shorter than disc width, with small dorsal/ventral finfolds. 1-3 irregular rows of small thorns dorsally on tail. Caudal stings positioned distally at end of tail.

Colour

Dorsum dark brown, reddish brown, or olive brown with a dense covering of light brown or orange spots that sometimes form a vermiculate pattern or irregular circles. Ventrum mostly white with grey spots towards margin or grey with a small white anterior region. Tail dark posteriorly.

Size

Maximum disc width 52cm. Disc width at birth approximately 14cm.

Habitat

Tropical freshwater lakes and river systems.

Distribution

South America. The reticulated freshwater stingray is confined to the Paraná-Paraguay and La Plata basins, and upper Amazon River basin in Boliva, Peru, and Brazil.

Conservation Status

DATA DEFICIENT

The Reticulated Freshwater Stingray (Potamotrygon falkneri) is a little known freshwater stingray from the Paraná River basin. There is essentially no information available on this species’ ecology or biology. As other potamotrygonids, it faces numerous identified threats including habitat degradation and fishing activities. Further evaluation when more information available will be required to assess this species beyond Data Deficient.

Citation

Góes de Araújo, M.L. 2009. Potamotrygon falkneriThe IUCN Red List of Threatened Species 2009: e.T161353A5404947. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161353A5404947.en. Downloaded on 08 March 2021.

Reproduction

Viviparous with trophodermic nutrition. 3 pups per litter reported.

Diet

Diet consists of insects, molluscs, crustaceans, and small fishes.

Behavior

Poorly known. Probably moves into seasonally flooded areas during periods of high water.

Reaction to divers

Unknown but probably difficult to approach.

Diving logistics

There are no records of divers encountering reticulated freshwater stingrays in the wild. South American freshwater river systems tend to be extremely turbid making underwater encounters challenging or impossible.

Similar species

Tatiana’s Freshwater Stingray Similarly patterned but distinguishable by longer tail and generally darker appearance.