The ocellate river stingray (''Potamotrygon motoro''), also known as the peacock-eye stingray or black river stingray, is a species of freshwater stingray in the family

Potamotrygonidae River stingrays or freshwater stingrays are Neotropical freshwater fishes of the family Potamotrygonidae in the order Myliobatiformes, one of the four orders of batoids, cartilaginous fishes related to sharks. They are found in rivers in tropic ...

. It was the first species to be described in the family and is also the most widespread, ranging throughout much of the

Río de la Plata The Río de la Plata (, "river of silver"), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda. It empties into the Atlantic Ocean and fo ...

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

, Mearim and Orinoco basins in tropical and subtropical South America.Loboda, T.S.; and de Carvalho, M.R. (2013)
Systematic revision of the Potamotrygon motoro (Müller & Henle, 1841) species complex in the Paraná-Paraguay basin, with description of two new ocellated species (Chondrichthyes: Myliobatiformes: Potamotrygonidae).
Neotropical Ichthyology 11(4): 693–737. It is sometimes kept in aquaria.

Taxonomy

''Potamotrygon motoro'' varies significantly in appearance and

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

over its large range,Loboda, T.S. (2010). Revisão taxonômica e morfológica de Potamotrygon motoro (Müller & Henle, 1841) na bacia Amazônica (Chondrichthyes: Myliobatiformes: Potamotrygonidae). University of São Paulo, Brazil. and a taxonomic review of the Amazonian populations is expected. The taxonomy of the populations in the

Río de la Plata Basin The Río de la Plata basin ( es, Cuenca del Plata, pt, Bacia do Prata), more often called the River Plate basin in scholarly writings, sometimes called the Platine basin or Platine region, is the hydrographical area in South America that drain ...

was reviewed in 2013, leading to the finding that ''P. motoro'' is found virtually throughout (absent from the

Paraná Basin The Paraná Basin ( pt, Bacia do Paraná, es, Cuenca del Paraná) is a large cratonic sedimentary basin situated in the central-eastern part of South America. About 75% of its areal distribution occurs in Brazil, from Mato Grosso to Rio Grande d ...

upriver from

Itaipu Dam The Itaipu Dam ( pt, Barragem de Itaipu , es, Represa de Itaipú ) is a hydroelectric dam on the Paraná River located on the border between Brazil and Paraguay. The construction of the dam was first contested by Argentina, but the negotiations ...

), but also that there are two additional members of this

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

: '' P. amandae'' (widespread in Río de la Plata Basin) and '' P. pantanensis'' (northern

Pantanal The Pantanal () is a natural region encompassing the world's largest tropical wetland area, and the world's largest flooded grasslands. It is located mostly within the Brazilian state of Mato Grosso do Sul, but it extends into Mato Grosso and ...

). Two highly distinctive Amazonian types completely lack black-edged yellow-orange spots: The so-called "Mantilla ray", CD4, in Peru and adjacent parts of Brazil, and the similar but paler CD5 from rivers near

Marajó Marajó () is a large coastal island in the state of Pará, Brazil. It is the main and largest of the islands in the Marajó Archipelago. Marajó Island is separated from the mainland by Marajó Bay, Pará River, smaller rivers (especially ...

. Both CD4 and CD5 co-occur with normal variants of ''P. motoro''. In 2019, they were described as a new species, '' P marquesi''. Currently recognized members of the species complex found elsewhere are '' P. boesemani'' (

Corantijn River The Courantyne/Corentyne/Corantijn River is a river in northern South America in Suriname and Guyana. It is the longest river in the country and creates the border between Suriname and the East Berbice-Corentyne region of Guyana. Its tributarie ...

; ''P. motoro'' absent), '' P. jabuti'' (mid and upper

Tapajós The Tapajós ( pt, Rio Tapajós ) is a river in Brazil. It runs through the Amazon Rainforest and is a major tributary of the Amazon River. When combined with the Juruena River, the Tapajós is approximately long. It is one of the largest clearw ...

Basin; ''P. motoro'' in the lower),Carvalho, M.R.d. (2016)
Description of two extraordinary new species of freshwater stingrays of the genus ''Potamotrygon'' endemic to the rio Tapajós basin, Brazil (Chondrichthyes: Potamotrygonidae), with notes on other Tapajós stingrays.
Zootaxa 4167(1): 1–63. and '' P. ocellata'' (lower Amazon Basin), but the last may be a synonym of ''P. motoro''.

Appearance

Panaque nigrolineatus and Potamotrygon motoro in Tropicarium-Oceanarium Budapest

''Potamotrygon motoro'' can grow up to in disc width, in

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

, and in weight. Its disk is roughly circular in shape, and its eyes are raised from the dorsal surface. The dorsal coloration is typically beige or brown, with numerous yellow-orange spots with dark rings. Its exact color, and the arrangement and size of the spots can vary significantly, both from individual to individual and depending on location. Three primary types have been identified in the Amazon basin, but each of these include a number of subtypes (two additional main types now are considered a separate species, ''P. marquesi''). The two main Amazonian types, informally known as CD1 and CD2, are found throughout much of the Amazon (except most of the Rio Negro basin) and they often occur together. Those from the Río de la Plata Basin and

Mearim River The Mearim River is a river in Maranhão state of northern Brazil. The river originates in the southern part of Maranhão, and drains north into the Baía de São Marcos, an estuary that also receives the Pindaré and Grajaú rivers, which are ...

resemble CD1. Individuals from the Rio Negro and Orinoco basins (which are connected by the

Casiquiare canal The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...

) are similar to each other and informally known as CD3, but differ from ''P. motoro'' elsewhere. Some individuals of CD3 have spots near the rim of the disc that are connected, forming a chain-like pattern. However, the "marbled" type is generally only reported from the Orinoco basin, including the

Ventuari River The Ventuari River is the largest tributary of the Orinoco in southern Venezuela. The Ventuari flows from south-central Venezuela in the Guiana Highlands southwest into the Orinoco River. It is long and its major tributary is the Manapiare River ...

In aquaria

Ocellate river stingrays are sometimes kept in captivity, with requirements similar to other members of ''

Potamotrygon ''Potamotrygon'' is a genus of freshwater stingrays in the family Potamotrygonidae native to the rivers of South America, and sometimes seen in the aquarium trade. Like other stingrays, the fishes of this genus have venomous barbs at the base of ...

''. It is one of the most popular species of freshwater stingrays, but requires a very large tank.SeriouslyFish
Potamotrygon motoro.
Retrieved 22 February 2017.

References

External links

* * {{Taxonbar, from=Q1297913 motoro Freshwater fish of Argentina Fish of Bolivia Freshwater fish of Brazil Freshwater fish of Colombia Freshwater fish of Ecuador Fish of Paraguay Freshwater fish of Peru Fish of Uruguay Fish of Venezuela Fish of the Amazon basin Fauna of the Pantanal Fish described in 1841 Taxa named by Johannes Peter Müller Taxa named by Friedrich Gustav Jakob Henle