Ben-Tuvia’s Sleeper Ray

Heteronarce bentuviai, a member of the Narkidae family within the order of electric rays, represents a distinctive species of cartilaginous fish known for its benthic habitat. This species is characterized by its large, flattened pectoral and pelvic fins, which form a disc-like shape, and a distinct tail with two dorsal fins. Notably, Heteronarce bentuviai possesses the ability to generate an electric current, an adaptation that supports its lifestyle within the tropical waters of the undefined, specifically as an endemic species of the Gulf of Aqaba. These rays are typically located at depths ranging from 80 to 200 meters, residing on sandy or muddy substrates.

The species exhibits pectoral fins that form an oval, round, or pear-shaped disc, and its scaleless skin adds to its streamlined form. The snout of the ray is elongated and broadly rounded, with a cartilaginous structure that is reduced to a thin medial rod. The nostrils, positioned directly in front of the mouth, are linked by a broad groove and surrounded by extended skin folds that coalesce to form a central flap partially covering the mouth.

Additionally, spiracles are situated behind the eyes, and the distinctive electric organs, kidney-shaped and visible through the skin, extend along the body from the pectoral fins to the disc's periphery. The maximum recorded length for Heteronarce bentuviai is 19.2 cm. The species displays a sandy-brown dorsal surface adorned with paired dark brown spots above the electric organs, as well as similar pigmentation at the base of the pectoral fins and on the first dorsal and caudal fins.

Heteronarce bentuviai engages in ovoviviparous reproduction, with embryos developing from eggs within the maternal body, nourished by both yolk and histotroph. This reproductive strategy further aligns the species with its specialized benthic marine lifestyle.