Black-tailed antenna ray

The black-tailed antenna ray or dwarf antenna ray (Plesiotrygon nana) is a species of freshwater stingray in the family Potamotrygonidae. It is native to the western Amazon basin in northeastern Peru, western Brazil (east to around the Purus mouth) and possibly eastern Ecuador.[1] It is found both in the mainstream of the Amazon River and in smaller tributaries such as the Itaya and Pachitea Rivers.[1][2] It is occasionally kept in aquariums and has been bred in captivity,[3][4] but it is sensitive and the tail is easily damaged.[5]

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).[1] The type specimen, an adult male, had a disc width of 24.7 cm (9.7 in), leading to speculations that the black-tailed antenna ray is the smallest member of the family.[1] However, a female kept at the Shedd Aquarium had a disc width of 38 cm (15 in).[5]