Panamic Stingray, Urotrygon aspidura
The Panamic Stingray, Urotrygon aspidura, whose common Spanish name is raya redonda panámica, is a member of the American Round Stingray or Urotrygonidae Family, known collectively as raya redondas Americanas in Mexico. Globally, there are thirteen species in the genus Urotrygon, five of which are found in Mexican waters, all in the Pacific.
These fish have flat oval bodies that are larger in depth than in length. Their discs have fairly straight front margins. They vary in color from grayish brown in the center to reddish brown at the disc edge. Their undersides are off white with a pinkish tinge. Their heads have small eyes and a pointed snout. Their eyes and spiracles are on top of their heads and their mouths, nostrils, and gill slits are on their ventral sides. Their pelvic fins have straight rear edges. Their tails are slightly longer than the disc length and have a narrow rounded caudal fin. They feature a row of six large thorns (a key to identification) running from the base to the middle of the tail which is followed by a large venomous spine. Their discs are sparsely covered with small denticles.
The Panamic Stingrays reside over and within sandy and muddy bottoms, but are occasionally found in rocky reef areas at depths up to 330 feet. They are most abundant at depths less than 50 feet and move to greater depths during cold-water episodes.
The Panamic Stingrays reach a maximum length of 50 cm (20 inches) with discs having a maximum width of 23 cm (9.1 inches), however most have disc diameters of less than 25 cm (10 inches). They seek food by stirring the bottom sediment with their pectoral fins to dislodge small crustaceans, small fish, mussels, and worms on which they feed. The pups are born alive and are miniature adults that are independent at birth. They are a rare and poorly studied species and as such very limited information is available about their behavioral patterns.
In Mexican waters the Panamic Stingray have a limited distribution being found in the from Guerrero Negro southward along the central and southwest coasts of Baja and along the coast of the mainland south to Guatemala. At present they have not been documented to reside in the Sea of Cortez.
The Panamic Stingray cannot be confused with any other species due to the row of six large thorns running from the base to the middle of the tail.
The Panamic Stingray is a rare species, seldom seen by humans. From a fishing perspective, they are only retained by subsistence fishermen and typically considered a “catch and release.”
Panamic Stingray, Urotrygon aspidura. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, May 2011. Total length: 52 cm (20 inches). Disc: 28 cm (11 inches) x 25 cm (10 inches). Tail: 24 cm (9.4 inches).