Blotched Stingray

Blotched Stingray, Urotrygon chilensis

The Blotched Stingray, Urotrygon chilensis, whose Spanish common name is raya redonda moteada, 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.

The Blotched Stingrays have wide oval disc-shaped bodies with a straight front margin and a slightly projecting snout; they are slightly wider than they are long. They are a uniform gray, gray-brown or tan color with irregular dark gray or black spots. Their underside is off-white with a brown border. Their pectoral fins are continuous around the head. They have large eyes and spiracles on top of their head. Their mouth, nostrils, and gill slits are located on the ventral side. Their tail is slender and about equal to the disc length with one large venomous spine located mid-tail. They have denticles scattered over the entire disc with patches between their eyes, on the sides below their eyes, along the back, and on top of and on the sides of their tail. They have one row of irregularly shaped thorns on the mid-back and tail.

The Blotched Stingrays reside over and within coastal sandy and muddy bottoms at depths up to 200 feet. They reach a maximum total length of 42 cm (17 inches) with a maximum disc width of 26 cm (10 inches). They seek food by stirring bottom sediment with their pectoral fins to dislodge small crustaceans, small fish, mussels, and worms on which they feed. Their 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.and of limited interest to most.

In Mexican waters the Blotched Stringrays are found in all waters of the Pacific with the exception that they are absent from Magdalena Bay northward along the central and northwest coasts of Baja.

The Blotched Stingray can be confused with the Panamic Stingray, Urotrygon aspidura, the Spiny Stingray, Urotrygon munda, and the Thorny Stingray, Urotrygon rogersi, however, neighter of these have the spotting pattern on their backs.

The Blotched Stringray is very rare and of limited interest to most.

Blotched Stingray, Urotrygon chilensis. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Total Length: 39 cm (15 inches). Disc: 22 cm (8.6 inches) x 23 cm (9.1 inches). Tail: 17 cm (6.7 inches). Photo and identification courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.