The black-tailed antenna ray (''Plesiotrygon nana'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of freshwater

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

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Potamotrygonidae. It is native to the western

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its 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 of Bolivi ...

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: * 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 technology c ...

and Putumayo Rivers 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 Rivers. 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 The long-tailed river stingray or antenna ray (''Plesiotrygon iwamae'') is a species of freshwater stingray in the family (biology), family Potamotrygonidae. It is found in the Amazon basin in South America, ranging from Ecuador to Belém. It liv ...

(''P. iwamae''). The

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

, 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 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 fish of Brazil Freshwater fish of Peru Fish of the Amazon basin Fish described in 2011