Lobed Stingaree

The lobed stingaree has a rounded pectoral fin disc much wider than long, with nearly straight leading margins. The snout is fleshy and forms an obtuse angle; the tip may protrude slightly past the disc. The medium-sized eyes are followed by teardrop-shaped spiracles, which have a rounded posterior margin. The outer posterior corner of each nostril forms a visible lobe. Between the nostrils is a skirt-shaped curtain of skin with a fringed trailing margin; the front corners of the curtain are enlarged into distinctive, semicircular lobes. The mouth is small and contains 9–10 papillae (nipple-like structures) on the floor; a handful of papillae are also found on the lower jaw. The small teeth have roughly oval bases. The five pairs of gill slits are short. The pelvic fins are small and rounded. The tail is slender and very flattened, measuring 87–100% as long as the disc and bearing a prominent horizontal skin fold on either side. There is a dorsally positioned, serrated stinging spine near the caudal fin, which is long, narrow, and leaf-shaped. There is no dorsal fin. The skin entirely lacks dermal denticles. This species is yellowish brown above, becoming slightly lighter at the lateral margins of the side, and white below; some individuals have irregular blotches and/or a dark stripe along the dorsal midline of the tail. The caudal fin becomes dark towards the tip. …

Among the most abundant representatives of its family within its range, the lobed stingaree is found along a short stretch of the southwest Australian coast from Esperance to Rottnest Island. This bottom-dwelling species favors sandy flats and seagrass beds, from the intertidal zone to a depth of 30 m (98 ft). In the southern portion of its range, it tends to be found relatively far from shore. Individuals of different ages and sexes are not segregated from each other.

Almost 90% of the food volume consumed by the lobed stingaree consists of crustaceans, in particular mysids, amphipods, shrimps, and cumaceans, which are captured on or just above the bottom. This species also feeds on polychaete worms, small bony fishes, and rarely molluscs. Rays smaller than 19 cm (7.5 in) across take relatively more mysids, amphipods, and cumaceans, while larger rays take more shrimps and fishes, and have a more diverse diet overall. Its dietary composition also shifts seasonally, mostly reflecting the greater availability of shrimp in summer and fall and cumaceans in winter and spring. A known parasite of this species is a tapeworm in the genus Acanthobothrium. The function of its unique nasal lobes is unknown. Like other stingrays, the lobed stingaree is aplacental viviparous. Females have a single functional uterus, on the left, and an annual reproductive cycle. Mating occurs in November and October and ovulation from mid-November and mid-January, implying that the females store sperm internally for 1–3 months before fertilization. The gestation period lasts ten months; although up to six eggs may be fertilized, usually only a single pup (rarely two) develops to term. …