''Plesiotrygon nana'', the black-tailed antenna ray, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of freshwater

stingray Stingrays are a group of sea Batoidea, rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwate ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Potamotrygonidae River stingrays or freshwater stingrays are Neotropical freshwater fishes of the family (biology), family Potamotrygonidae in the Order (biology), order Myliobatiformes, one of the four orders of Batoidea, batoids, cartilaginous fishes related to ...

. It is native to the western

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

in northeastern Peru, western Brazil (east to around the Purus mouth), southeastern Colombia, and possibly eastern Ecuador. It is found both in the mainstream of the

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

and

Putumayo River The Putumayo River or Içá River (, ) is one of the tributaries of the Amazon River, southwest of and parallel to the Japurá River. Course The Putumayo River forms part of Colombia's border with Ecuador, as well as most of the border with Per ...

s and in smaller tributaries such as the

Itaya ''Itaya amicorum'' is a medium-size fan palm that is native to Brazil, Colombia and Peru. It is the only species in the genus ''Itaya''. It was unknown to science until 1972, when it was discovered on the bank of the Itaya River in the Peruvian ...

and

Pachitea River The Pachitea River is a river in Peru. It is a left tributary of the Ucayali River The Ucayali River (, ) is the main headstream of the Amazon River. It rises about north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon ...

s. It is occasionally kept in aquariums and has been bred in captivity, but it is sensitive and the tail is easily damaged. The black-tailed antenna ray is very long-tailed (tail length typically at least three times the disc width), similar to the only other member of the genus, the long-tailed river stingray (''P. iwamae''). The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

, an adult male, had a disc width of , leading to speculations that the black-tailed antenna ray is the smallest member of the family ("''nana''" means small and it has also been referred to by the name dwarf antenna ray). However, a female kept at the

Shedd Aquarium Shedd Aquarium (formally the John G. Shedd Aquarium) is an indoor public aquarium in Chicago. Opened on May 30, 1930, the aquarium holds about 32,000 animals. It is the third largest aquarium in the Western Hemisphere (after the Georgia Aquariu ...

had a disc width of , and later specimens caught in the wild have been up to in width and in weight.

References

{{Taxonbar, from=Q5024267 Potamotrygonidae Freshwater stingrays of Brazil Freshwater fish of Peru Fish of the Amazon basin Fish described in 2011