Preying on crustaceans, cephalopods, and bony fishes, the deepwater stingray may hunt both on the sea floor and well above it in open water.

The first scientific description of the deepwater stingray was authored by John H. Wallace, as part of a 1967 Investigational Report from the Oceanographic Research Institute, Durban.

Therefore, he moved this species to its own genus, Plesiobatis, and family, Plesiobatidae; the name is derived from the Greek plesio ("primitive") and batis ("ray").

John McEachran, Katherine Dunn, and Tsutomu Miyake in 1996 could not fully resolve the position of Plesiobatis, thus they assigned it provisionally to the family Hexatrygonidae.

The slender caudal fin originates a short distance behind the sting; it is symmetrical above and below, and terminates in a rounded leaf-like shape.

The skin is densely covered by fine dermal denticles, that become sparse to absent on the pelvic fins, towards the ventral disc margin, and around the mouth.

[1][4] Its long, flexible snout is well-suited for rooting through sediment, while the presence of mesopelagic species in its diet suggest that it may also hunt well above the sea floor.

[11] One recorded individual was found severely gouged by kitefin sharks (Dalatias licha), which are capable of excising plugs of flesh, cookiecutter-like, from larger animals.

The young are apparently born at close to 50 cm (20 in) long, as evidenced by the capture of a free-living specimen of that size that still bore a yolk sac scar.

[1][2][10] When captured, the deepwater stingray flails its powerful tail violently, and its long, venomous sting can inflict a serious injury to a fishery worker.

As a result, the International Union for Conservation of Nature has determined this species to be minimally threatened by human activity, and listed it under least concern.