Motoro Stingray - Potamotrygon motoro

Motoro stingray

Motoro stingray picture

Motoro stingray color variant

All photographs copyright Andy Murch

View all available Motoro Stingray Pictures in the shark picture database.

Common Names: Peacock ray, Peacock-eye stingray, Motoro ray, Ocellate river stingray, Black river stingray, South American freshwater stingray.

Other recorded names:

侧头江魟 China Mandarin Chinese

側頭江魟 China Mandarin Chinese

南美江魟 China Chinese

скат речной Russian

хвостокол речной Russian

Arraia de fogo Brazil Portuguese

Gemeiner Stechrochen Germany German

Pauwoogzoetwaterrog Netherlands Dutch

Pfauenaugen-Stechrochen Germany German

Raya amazónica Peru Spanish

Raya motoro Peru Spanish

Riikinkukkorausku Finland Finnish

Guarani Argentina

Øjeplettet flodpigrokke Denmark Danish

Latin Name: Potamotrygon motoro, Potamotrygon laticeps (incorrect).

Family: Potamotrygonidae

A note on the identification of South American Freshwater Stingrays. Dorsum patterns and colors are extremely variable among the freshwater rays of South America making positive identification using pattern and coloration alone extremely difficult. Some morphologically different species occasionally display an almost identical pattern and to make identification even harder there can be a degree of hybridization among sympatric species. Important characteristics to help the observer overcome these problems include the lateral markings on the tail, the presence or lack of raised denticles along the tail, the ratio of tail length to disc length, and the size and position of the eyes (although this last characteristic changes with age).

Identification: Motoro rays often exhibit bold, orange/tan, circular or slightly ovoid spots ringed in black on a grey/brown background. In some cases the spots have further tan ring outside the black one. But, like other potamotrygonids, color and pattern can vary as illustrated by the third motoro ray image shown above. To complicate matters there are actually three recognized species of motoro rays. Two of which have not been fully described:

P. motoro is the original holotype from the Rio Cuiaba in Brazil as described above.

P. motoro species A (the Smooth shortnose motoro ray) from Peru is almost identical but has a rounder body disc, shorter snout and smoother dorsum. The dorsal pattern is consistent with P.motoro except that the spots tend to be smaller and uniformly sized over the whole disc except at the very edges.

P. motoro species B (the Longtail motoro ray) has a similar pattern but can be distinguished from P. motoro by its longer and less powerful tail. It also has less (and smaller) raised denticles on the upper surface of its tail.

Size: 99cm total length.

Habitat: South American river basins. 24-26 degrees C.

Abundance and distribution: Freshwater river systems in Uruguay, Parana-Paraguay, Orinoco and Amazon River systems.

Reproduction: Matrotrophic viviparity.

Observations:

Similar species: Other than the undescribed motoro species mentioned above, the closest described relative of the Motoro stingray is the Red Kidney-spot Motoro Ray Potamotrygon ocellata. It differs in having kidney shaped and irregularly shaped spots on its dorsum rather than round ocelli. The ocelli are generally a dark red to rusty brown in color.

Reaction to divers: Reportedly aggressive to fishermen and other river users that inadvertently disturb this ray. Rarely if ever encountered by divers.

Diving logistics: There are currently no organized opportunities to interact with motoro stingrays but aquarist collecting sites include Paraguay and Brazil.

Other diving locations submitted by readers:

References and further reading:

Aqualog Freshwater Rays. Richard Ross & Frank Schafer

Fishbase.com

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