Roughnose stingray

degradation

type specimen is an adult male 41 cm (16 in) across, collected from the fish market in Mukah, Sarawak, Malaysia.^[2]

freshwater outflow from rivers. It has been recorded to a depth of 30 m (98 ft) but most occur shallower than 10 m (33 ft).^[1][2]

nares, with its posterior margin forming two distinct lobes. The upper jaw is strongly curved with the center projecting downwards at a right angle, abutting the center of the bow-shaped lower jaw. The large, blunt teeth have hexagonal crowns and are arranged in a quincunx pattern. There are around 20 upper tooth rows and 25 lower tooth rows. Five papillae are found in a row across the floor of the mouth, with the outermost pair smaller and set apart from the others.^[2]

dermal denticles almost to the margins; a transverse row of 1–3 enlarged thorns, with the central one the largest and pearl-like, is present in the middle of the back. Denticles are also present on the back and sides of the tail, at the base and behind the sting. In life, the back is covered by a thick layer of mucus. The dorsal coloration is plain olive to brown, becoming pinkish towards the disc margins and on the pelvic fins, and darkening to almost black towards the tip of the tail. The underside is nearly white, becoming pinkish towards the fin margins. The pointed, denticle-covered snout distinguishes this species from the rest of the genus.^[2] The maximum known disc width is 72 cm (28 in).^[1]

aplacental viviparous; developing embryos are nourished by yolk, later supplemented by histotroph ("uterine milk") produced by the mother. One recorded female was gestating a single late-term fetus. Newborns measure 22–23 cm (8.7–9.1 in) across; males attain sexual maturity at a disc width of 28–40 cm (11–16 in), and females at a disc width of 50–60 cm (20–24 in).^[1]

Endangered.^[1]