The Blurred Lanternshark is a little-known species of dogfish shark in the family Etmopteridae. It has been assessed as of Least Concern by the International Union for Conservation of Nature, because of its wide distribution and lack of threat from fishing pressure.
Growing to a length of at least 67 cm (26 in), the blurred lanternshark has a slender body, large head, and short tail. The snout is wedge-shaped and slightly flattened, tapering to a point. The nostrils are large, with short flaps of skin in front. The eyes are oval in shape with a deep anterior notch in the orbit. The mouth has long furrows at the corners that extend halfway to the first of five gill slits. There are 19–24 tooth rows in the upper jaw, each with a narrow central cusp flanked by 2–4 pairs of smaller cusplets, increasing in number with age in males over 45 cm (18 in) long. There are 25–39 tooth rows in the lower jaw, each tooth with a smooth-edged, knife-like cusp and their bases interlocked to form a single cutting surface; the teeth of males over 43 cm (17 in) long and females over 35 cm (14 in) long become more erect with age.
The first dorsal fin is close to the pectoral than the pelvic fins, and bear a straight, grooved spine in front. The second dorsal fin is half again as tall as the first and bears a longer, curved spine. The pectoral fins are rounded at the tips, with the distance between them and the medium-sized, angular pelvic fins about equal to the distance between the dorsal fins. The anal fin is absent. The caudal peduncle is narrow, leading to a caudal fin with a well-developed lower lobe and a broad upper lobe with a ventral notch near the tip. The small, blocky dermal denticles are densely but irregularly arranged, each with a flat, truncate crown. The coloration is brown or gray above, with a pale spot over the pineal gland, and black below extending in faint markings over the sides of the head, under the pectoral fins, over the pelvic fins, and below the caudal peduncle. Like other lanternsharks, the blurred lanternshark possesses a species-specific light-emitting photophores, which are not placed in prominent bands. The blurred lanternshark is very similar to the smooth lanternshark, but is larger and can be reliably differentiated by the number of turns in the spiral valve intestine (16–19 versus 10–13).
It is partially pelagic and occurs at depths of 110–700 m (360–2,300 ft) in open water, and from 163 m (535 ft) to over 1 km (0.62 mi) near the bottom. Like many other lantern sharks, adults are found deeper than juveniles.
The diet of the blurred lanternshark consists of squid, smaller dogfish sharks, lanternfishes, and fish eggs.