Roughtail Stingray

The roughtail stingray has a diamond-shaped pectoral fin disk 1.2–1.3 times as wide as long, with straight to gently sinuous margins, rather angular outer corners, and a moderately long, obtuse snout. The eyes are proportionally smaller than other stingrays in its range and immediately followed by larger spiracles. There is a curtain of skin between the nostrils with a finely fringed posterior margin. The mouth is bow-shaped with a row of six papillae (nipple-like structures) across the floor. The seven upper and 12–14 lower tooth rows at the center are functional, though the total number of tooth rows is much greater. The teeth are arranged with a quincunx pattern into flattened surfaces; each has a tetragonal base with a blunt crown in juveniles and females, and a pointed cusp in adult males.

The roughtail stingray is broadly but discontinuously distributed in the coastal waters of the western Atlantic Ocean. It occurs from the Georges Bank off Cape Cod, Massachusetts following warm ocean waters southward to Florida, the Bahamas, and the northeastern Gulf of Mexico; there are also scattered reports from Venezuela to Argentina and on the Barrier reef in Belize. A single record from Kollam, India was likely a misidentification.

One of the deepest-diving stingrays, the roughtail stingray has been recorded to a depth of 274 m (899 ft) in the Bahamas. However, it is most common at a depth of 15–50 m (49–164 ft). This bottom-dwelling species favors live-bottom habitat (patches of rough terrain that are densely encrusted by sessile invertebrates), and also frequents adjacent open areas of sand or mud. Rays in the northwestern Atlantic do not usually enter brackish water.

The roughtail stingray is reportedly not highly active, spending much time buried in the sediment. It is a generalist predator whose diet generally reflects the most available prey in its environment. It mainly captures prey off the bottom, but also opportunistically takes free-swimming prey. A variety of invertebrates, as well as bony fishes such as sand lance and scup, are known to be consumed. Off Massachusetts, the main prey are crabs (Cancer), bivalves (Mya), gastropods (Polinices), squid (Loligo) and annelid worms. In Delaware Bay, most of its diet consists of the sand shrimp Crangon septemspinosa and the blood worm Glycera dibranchiata; the overall dietary composition there is nearly identical to that of bluntnose stingrays (Hypanus say) that share the bay. The shrimp Upogebia affinis is a major food source off Virginia.

With its large size and long, venomous spine, the roughtail stingray can inflict a severe wound and can be very dangerous for fishers to handle. However, it is not aggressive and usually occurs too deep to be encountered by beachgoers. It has been reported to damage farmed shellfish beds. The pectoral fins or "wings" are sold for human consumption fresh, smoked, or dried and salted; the rest of the ray may also be processed to obtain fishmeal and liver oil. The International Union for Conservation of Nature (IUCN) has assessed the roughtail stingray as of Least Concern worldwide, while noting that as a large, slow-reproducing species it is susceptible to population depletion.