SMOOTH LANTERNSHARK OR SLENDER LANTERNSHARK

Taxonomy:

Phylum– Chordata

Class– Chondrichthyles

Subclass– Elasmobranchii

Order– Squaliformes

Common Name– Dogfish Sharks

Family– Etmopteridae

Common Name– Lantern Sharks

Genus– Etmopterus

Species– pusillus

Status: IUCN Red List LEAST CONCERN

Average Size and Length: Adult males have been measured between 1-1.3 feet. Adult females have been measured between 1.2-1.5 feet. The maximum is believed to be between 1.6-3.3 feet.

Teeth and Jaw: The teeth in the upper and lower jaws differ. The upper teeth generally have 3 pairs of cusplets. There are 22–31 tooth rows in the upper jaw and 30–53 tooth rows in the lower jaw. Each upper tooth has a narrow smooth-edged central cusp flanked by 1–2 tiny cusplets. Mature males over 15 inches long grow additional pairs of lateral cusplets with age. The lower teeth are smooth, knife-like, and angled, with their bases interlocking to form a continuous cutting surface.

Head: The Smooth lanternshark has a large head with a pointed snout, large oval eyes, and nostrils with short anterior skin flaps.

Denticles: The skin of the Smooth lanternshark or Slender lanternshark, like its name appears smooth. There are wide-spaced, low-crowned cuspless dermal denticles that are not arranged in rows. The snout is covered in dermal denticles.

One interesting observation is that the Smooth lanternshark forms a species group with the Blurred lanternshark. Both of these sharks are distinguished from other members of their family by small, irregularly arranged dermal denticles with a truncated shape.

Tail: The caudal fin is short and broad. There is a well-developed lower lobe and a ventral notch near the tip of the upper lobe.

Demographic, Distribution, Habitat, Environment and Range: The Smooth lanternshark or Slender lanternshark can be found in the Atlantic Ocean and the Gulf of Mexico widespread. They are found in the Mid-Atlantic Ridge. They are also found in the Indo-west Pacific in South Africa (Cape Verde and the Azores) and Japan. In the Indian Ocean, it is found off KwaZulu-Natal and Madagascar. They are also found over the Nazca Plate. They are found over the continental slopes on or near the bottom between 900-3,280 feet, but possibly as deep as 6,555 feet. Here they are considered benthic. In the south Atlantic they are oceanic. They can be found between 0-2,323 feet over deep water in pelagic zones. Catch data off southern Portugal suggest they have a preference for rocky substrates, and may conduct a diel vertical migration. They have also been observed swimming over fields of hydrothermal vents.

Diet: The Smooth lanternshark eats fish eggs, they eat lanternfish, squid, very small sharks and hake.

Aesthetic Identification: The Smooth lanternshark or Slender lanternshark is a small, lightly-built shark, and like its name, a slender shark. The body is blackish brown in color. There is an obscure broad black mark above, in front, and behind the pelvic fins. The gill slits are long. The first dorsal fin has a stout, grooved spine in front and originates over the free rear tips of the rounded pectoral fins. The second dorsal fin is much larger than the first and has a longer spine. The second dorsal fin is less than twice the area of the first. The pelvic fins are low and angular, and there is no anal fin.

Biology and Reproduction: The Smooth lanternshark or Slender lanternshark is ovoviviparous. Females produce an average of 10 young per litter. They are slower to grow according to research. Males reach sexual maturity at a length of 12–15 inches, and females at a length of 15–19 inches, but these numbers can vary depending on region. Off southern Portugal, males live to at least 13 years of age, and females to at least 17 years of age.

The Smooth lanternshark and the Blurred lanternshark two differ in a number of anatomical characteristics, but can be most reliably distinguished by the number of turns in their spiral valve intestines (10–13 in E. pusillus versus 16–19 in E. bigelowi).

Behavioral Traits, Sensing and Intelligence: Unknown.

Smooth Lanternshark Future and Conservation: The Smooth lanternshark is not of concern. They are caught and utilized as bycatch in the bottom longline fisheries of the east Atlantic. More juveniles are caught than mature sharks. Mostly by longline, and occasionally trawls. Most are discarded. On occasion the meat is sold and utilized. Due to the growing fishing efforts and the rate of growth, it is possible that the Smooth lanternshark could fall vulnerable at some point in time, so it is important to recognize this and be proactive instead of reactive.

Smooth Lanternshark Recorded Attacks on Humans: Not a threat to humans.