Southern stingray
| Southern stingray | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Order: | Myliobatiformes |
| Family: | Dasyatidae |
| Genus: | Dasyatis |
| Species: | D. americana |
| Binomial name | |
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Dasyatis americana (Hildebrand & Schroeder, 1928) |
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| Range of the southern stingray | |
The southern stingray (Dasyatis americana) is a whiptail stingray found in tropical and subtropical waters of the Western Atlantic Ocean from New Jersey to southern Brazil. It has a flat, diamond-shaped disc, with a mud brown, olive, and grey dorsal surface and white underbelly (ventral surface). The barb on its tail is serrated and covered in a venomous mucous, used for self-defense.
The southern stingray is adapted for life on the sea bed. The flattened, diamond-shaped body has sharp corners, making it more angular than the discs of other rays. The top of the body varies between olive brown and green in adults, dark grey in juveniles, whilst the underside is predominantly white. The wing-like pectoral fins are used to propel the stingray across the ocean bottom, whilst the slender tail possesses a long, serrated and venomous spine at the base, used for defence. These spines are not fatal to humans, but are incredibly painful if stepped on. The eyes are situated on top of the head of the southern stingray, along with small openings called spiracles. The location of the spiracles enables the stingray to take in water whilst lying on the seabed, or when partially buried in sediment. Water enters the spiracles and leaves through the gill openings, bypassing the mouth which is on the underside. Female stingrays can grow to a disc width of 150 cm, contrary to the smaller male stingrays that reach maximum size at 67 cm.
Southern stingrays are nocturnal predators, who spray water from their mouths or flap their fins vigorously to disturb the substrate and expose hidden prey. This bottom-dwelling species is often found singly or in pairs, and can reach population densities estimated up to 245 per km2 in certain shallow systems thought to be nursery grounds.Dasyatis americana exhibit wave-like locomotion using their pectoral fins. This wave-like motion is important for Dasyatis americana because it allows them to escape predators, forage efficiently, and generally maneuver quickly. Typically, they travel large distances and their foraging area is very expansive. One study provided observations that Dasyatis americana swim along the tide, because of the greater food availability along tides. Dasyatis americana are able to do this because of their high maneuverability and efficient wave-like locomotion. Dasyatis americana either remain solitary or form groups. Groups of Dasyatis americana are usually observed when they mate, for predator protection or even when they are just resting.
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Wikipedia