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
