Scott Hanko
Roughtail Stingray
The roughtail stingray (Dasyatis centroura) is a species of stingray in the family Dasyatidae, with separate populations in coastal waters of the northwestern, eastern, and southwestern Atlantic Ocean. This bottom-dwelling species typically inhabits sandy or muddy areas with patches of invertebrate cover, at a depth of 15–50 m (49–160 ft). It is seasonally migratory, overwintering in offshore waters and moving into coastal habitats for summer. The largest stingray in the Atlantic, the roughtail stingray grows up to 2.6 m (8.5 ft) across and 300 kg (660 lb) in weight. It is plain in color, with an angular, diamond-shaped pectoral fin disc and a long, whip-tail tail bearing a subtle fin fold underneath. The many thorns on its back and tail serve to distinguish it from other stingrays that share its range.
Often found lying on the bottom buried in sediment, the roughtail stingray is a generalist predator that feeds on a variety of benthic invertebrates and bony fishes. It is aplacental viviparous, with the embryos receiving nourishment initially from yolk, and later from histotroph ("uterine milk") produced by the mother. In the northwestern Atlantic, females bear an annual litter of 4–6 young in fall and early winter, after a gestation period of 9–11 months. By contrast, in the Mediterranean there is evidence that females bear two litters of 2–6 young per year after a gestation period of only four months. Rays in the northwestern Atlantic are also larger at birth and sexual maturity than those from the Mediterranean. The venomous tail spine of the roughtail stingray is potentially dangerous to humans. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern overall and in the northwestern Atlantic, where it is not commercially utilized. However, in the Mediterranean and southwestern Atlantic it is subject to heavy fishing pressure and has been assessed as Near Threatened.
The roughtail stingray is broadly but discontinuously distributed in the coastal waters of the Atlantic Ocean. In the western Atlantic, it occurs from the Georges Bank off New England southward to Florida, the Bahamas, and the northeastern Gulf of Mexico; there are also scattered reports from Venezuela to Argentina. In the eastern Atlantic, it occurs from the southern Bay of Biscay to Angola, including the Mediterranean Sea, Madeira, and the Canary Islands. A single record from Quilon, 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 and regularly occurs down to 200 m (660 ft) in the Mediterranean. However, it is most common at a depth of 15–50 m (49–160 ft).[6] 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, whereas those off West Africa have been recorded from the lower reaches of large rivers.
The favored temperature range of the roughtail stingray is 15–22 °C (59–72 °F), which is the most important factor determining its distribution. It conducts seasonal migrations off the eastern United States: from December to May, this ray is found over the middle and outer parts of the continental shelf from Cape Hatteras in North Carolina to Florida, with larger rays occurring further south than smaller ones. In the spring, the population moves north of the Cape and towards the coast into bays, inlets, and saltier estuaries, though preserving the north-south gradient of body sizes. A similar migration, from shallow coastal waters in summer to deeper offshore waters in winter, apparently occurs in the Mediterranean. Pregnant females tend to be found apart from other individuals.
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 pelvic fins have nearly straight margins and angular tips. The tail is long and whip-like, measuring some 2.5 times the length of the disc. A long, saw-toothed spine is placed atop the tail at around half a disc length back from the tail base; sometimes one or two replacement spines are also present in front of the existing one. Behind the spine, there is a long ventral fin fold that is much lower than that of the southern stingray. Individuals under 46–48 cm (18–19 in) across have completely smooth skin. Larger rays develop increasing numbers of distinctive tubercles or bucklers (flat-based thorns) over the middle of the back from the snout to the tail base, as well as dorsal and lateral rows of thorns on the tail. The bucklers vary in size, with the largest of equal diameter to the eye, and may bear up to three thorns each. This species is a uniform dark brown or olive above, and off-white below without dark fin margins. Among the largest members of its family, the roughtail stingray can reach 2.6 m (8.5 ft) across, 4.0 m (13.1 ft) long, and 300 kg (660 lb) in weight. Females grow larger than males.
New York Aquarium Coney Island NY
Roughtail Stingray
The roughtail stingray (Dasyatis centroura) is a species of stingray in the family Dasyatidae, with separate populations in coastal waters of the northwestern, eastern, and southwestern Atlantic Ocean. This bottom-dwelling species typically inhabits sandy or muddy areas with patches of invertebrate cover, at a depth of 15–50 m (49–160 ft). It is seasonally migratory, overwintering in offshore waters and moving into coastal habitats for summer. The largest stingray in the Atlantic, the roughtail stingray grows up to 2.6 m (8.5 ft) across and 300 kg (660 lb) in weight. It is plain in color, with an angular, diamond-shaped pectoral fin disc and a long, whip-tail tail bearing a subtle fin fold underneath. The many thorns on its back and tail serve to distinguish it from other stingrays that share its range.
Often found lying on the bottom buried in sediment, the roughtail stingray is a generalist predator that feeds on a variety of benthic invertebrates and bony fishes. It is aplacental viviparous, with the embryos receiving nourishment initially from yolk, and later from histotroph ("uterine milk") produced by the mother. In the northwestern Atlantic, females bear an annual litter of 4–6 young in fall and early winter, after a gestation period of 9–11 months. By contrast, in the Mediterranean there is evidence that females bear two litters of 2–6 young per year after a gestation period of only four months. Rays in the northwestern Atlantic are also larger at birth and sexual maturity than those from the Mediterranean. The venomous tail spine of the roughtail stingray is potentially dangerous to humans. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern overall and in the northwestern Atlantic, where it is not commercially utilized. However, in the Mediterranean and southwestern Atlantic it is subject to heavy fishing pressure and has been assessed as Near Threatened.
The roughtail stingray is broadly but discontinuously distributed in the coastal waters of the Atlantic Ocean. In the western Atlantic, it occurs from the Georges Bank off New England southward to Florida, the Bahamas, and the northeastern Gulf of Mexico; there are also scattered reports from Venezuela to Argentina. In the eastern Atlantic, it occurs from the southern Bay of Biscay to Angola, including the Mediterranean Sea, Madeira, and the Canary Islands. A single record from Quilon, 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 and regularly occurs down to 200 m (660 ft) in the Mediterranean. However, it is most common at a depth of 15–50 m (49–160 ft).[6] 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, whereas those off West Africa have been recorded from the lower reaches of large rivers.
The favored temperature range of the roughtail stingray is 15–22 °C (59–72 °F), which is the most important factor determining its distribution. It conducts seasonal migrations off the eastern United States: from December to May, this ray is found over the middle and outer parts of the continental shelf from Cape Hatteras in North Carolina to Florida, with larger rays occurring further south than smaller ones. In the spring, the population moves north of the Cape and towards the coast into bays, inlets, and saltier estuaries, though preserving the north-south gradient of body sizes. A similar migration, from shallow coastal waters in summer to deeper offshore waters in winter, apparently occurs in the Mediterranean. Pregnant females tend to be found apart from other individuals.
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 pelvic fins have nearly straight margins and angular tips. The tail is long and whip-like, measuring some 2.5 times the length of the disc. A long, saw-toothed spine is placed atop the tail at around half a disc length back from the tail base; sometimes one or two replacement spines are also present in front of the existing one. Behind the spine, there is a long ventral fin fold that is much lower than that of the southern stingray. Individuals under 46–48 cm (18–19 in) across have completely smooth skin. Larger rays develop increasing numbers of distinctive tubercles or bucklers (flat-based thorns) over the middle of the back from the snout to the tail base, as well as dorsal and lateral rows of thorns on the tail. The bucklers vary in size, with the largest of equal diameter to the eye, and may bear up to three thorns each. This species is a uniform dark brown or olive above, and off-white below without dark fin margins. Among the largest members of its family, the roughtail stingray can reach 2.6 m (8.5 ft) across, 4.0 m (13.1 ft) long, and 300 kg (660 lb) in weight. Females grow larger than males.
New York Aquarium Coney Island NY