Brazilian Large-eyed Stingray: Hypanus marianae

Family: Dasyatidae
Common name(s)

Brazilian Large-eyed Stingray, Large-eye Stingray.

Binomial

Hypanus marianae.

Synonyms

Dasyatis macrophthalma, Dasyatis marianae.

Identification

A small stingray with a weakly kite-shaped disc that is slightly longer than wide in adults. Snout obtusely angular without a protruding tip. Anterior margins of disc weakly convex. Pectoral fin apices narrowly rounded. Pelvic fins small, with narrowly rounded apices.
Eyes large and protruding. Snout length ~1.1 x combined eye and spiracle length.
Mouth with 3 central oral papillae. Deep labial furrows around mouth. Lower jaw concave at symphysis. Skirt shaped nasal curtain. Nostrils oval, not positioned obliquely.
Skin smoothe; without denticles. A row of small thorns along midline from nape towards but not reaching tail. Males have a single thorn on each shoulder. Tail fairly wide, tapering evenly towards short filamentous tip. Tail length less than 2x disc width. Ventral finfold deeper than tail height. Dorsal finfold relatively prominent, approx. half ventral fin height. Dorsal finfold terminates above ventral finfold terminus. One tail sting usually present.

Colour

Dorsum yellowish-brown. Paler towards centre line. Dark blotches across eyes and on shoulders. Dusky longitudinal stripes either side of midline and on pectoral fins. Ventrum white with 2 dark paired markings. Tail white laterally near base, turning completely white on filamentous section beyond finfolds, then fading abruptly to black, roughly one ventral finfold length beyond finfold. Finfolds and sting dark.

Size

Maximum disc width at least 31cm. Disc width at birth 12-15cm.

Brazilian Large-eyed Stingray, Hypanus marianae. Natal, Brazil, western Atlantic Ocean.

Conservation Status

VULNERABLE

The Brazilian large-eyed stingray (Hypanus marianae) is captured and retained in commercial and artisanal fisheries throughout its range. This species is confined to shallow water (max 30m) where fishing pressure is extremely intense and (in the case of artisanal fisheries) often unmanaged. Consequently, the large-eye stingray population is thought to have decreased by 50-79% in the last three decades.

Brazilian Large-eyed Stingray, Hypanus marianae. Natal, Brazil, western Atlantic Ocean.
Habitat

Shallow, tropical/sub-tropical seas. On sandy or muddy substrates, seagrass beds, estuaries, and coral reefs. 1 to 50m depth.

Distribution

Wetern Atlantic, endemic to north/central Brazil; from Belem southward to Caravelas in southern Bahia.

Reproduction

Aplacental viviparous. 1 pup per litter. Gestation length 6-7 months. Usually two litters per year.

Diet

Diet unknown.

Behavior

Enters shallower water during high tide.

Reaction to divers

Sometimes skittish and difficult to approach but occasionally docile around divers.

Diving logistics

Brazilian Large-eyed stingrays are commonly encountered at Maracajaú; about one hour drive north of Natal. Diving platforms are moored next to shallow 2-3m deep reefs, 15 minutes from shore.
This species can also be seen on the reefs just south of the city of Natal. They are apparently also common at the Abrolhos Archipelago.

Similar species

Lutz’s Stingray Easily distinguished by much larger size, less protruding eyes, and lack of large dark blotches.