Sparsely-spotted Stingaree, Urolophus paucimaculatus
The sparsely-spotted stingaree (Urolophus paucimaculatus) also called the white-spotted stingaree or the Dixon’s stingaree, is found most commonly off the coast of southern Australia. It prefers sandy bottoms and seagrass beds close to shore out to a depth of 490 feet.
Its distribution ranges from Crowdy Head to Lancelin and the entire coast of Tasmania. Over the last few decades it has expanded further south apparently from climate change. This bottom-dwelling ray can be found in very shallow inlets and bays or in the open ocean on the continental shelf.
The disc of the sparsely-spotted stingaree is diamond shaped that is wider than long with rounded corners. The snout protrudes slightly and the small eyes are followed by comma-shaped air holes. The nostrils enlarge toward the back and a bell-shaped layer of skin sets between them. The mouth is small and contains five or six nipple-like structures on the floor and most have forked tips with others being located outside the lower jaw. The teeth are small and oval arranged in a quincunx (a die five) pattern. It has five pairs of gill slits that are short.
The tail is 77 to 98 percent as long as the disc and is flat at the base, becoming slender toward the tip. The tail fin is leaf-shaped and there is a fold of skin on each side of the tail. On the top side of the tail is a serrated stinging spine about halfway. The tail fin is dark in juveniles that lighten with age.
The color is usually a light gray with a dark V-shaped mark between the eyes. The belly is white with a darker shade on the outer disc. There are usually white spots arranged on the top of the disc with a dark border on each. The largest known sparsely-spotted stingaree measures 22 inches long.
This species of ray is considered to be nocturnal, spending most of the day buried in the sandy bottom. Its diet consists of a variety of prey including, crustacean and shrimp as their main food source but will also prey on polychaete worms. Occasionally it will eat mollusk, echinoderms and small fish. As the species ages, the more variety of prey it will consume.
Once the embryos consume all the supply of yolk, it will feed on the mother’s uterine milk until born. Depending on the female’s size the litter of pups can range from one to six. Usually ovulation occurs in the spring or early summer and there is a year long gestation period. Sexual maturity occurs in 2.5 years in males and 3 years in females. The female lives longer than the male on average with a maximum lifespan of 14 years. The female also grows slower but is larger than the male.
The sparsely-spotted stingaree seems to be more aggressive toward humans than other stingray species. Its stinger can produce a painful injury. The meat is edible but rarely brought to market. Unlike other stingray, it is more resistant to capture and release by trawlers and fisherman, although pregnant females tend to abort their young.
Although they are incidentally caught by commercial fisherman in abundance, the International Union for Conservation of Nature has listed them as least concern due to their population.
Image Caption: Sparsely-spotted stingaree (Urolophus paucimaculatus). Credit: dennis and aimee jonez/Wikipedia (CC BY-SA 2.0)