It can with tail be as long as 12' and weigh 520 pounds as the photos show The Mekong freshwater stingray was first recognized as a new species by Yasuhiko Taki, who included it as "Dasyatis sp."

Taki's specimens were subsequently lost, and this ray was not formally described until 1987, by Tyson Roberts and Jaranthada Karnasuta, in the scientific journal Environmental Biology of Fishes.

[2] A 1999 phylogenetic analysis, based on cytochrome b sequences, found that the Mekong freshwater stingray is closely related to an undescribed dasyatid species from the Gulf of Thailand.

[2][4] The pectoral fin disc of the Mekong freshwater stingray is oval in shape and slightly longer than wide.

There is also a narrow band of minute granular or pointed denticles on the back, which are confined by a pair of parallel lines drawn backward from the spiracles.

[2] The maximum known disc width of the Mekong freshwater stingray is 62 cm (24 in);[5] it can reportedly reach a weight of 30 kg (66 lb).

[4] However, a greater threat to the survival of this species is widespread habitat degradation within its limited range, from dam construction, agricultural runoff, and industrial pollution.