Etmopterus

Etmopterus is a genus of lantern sharks in the family Etmopteridae, order Squaliformes, comprising more than 40 described species. Members of this genus are small to medium-sized deep-sea sharks known for their bioluminescent organs, or photophores, which run in patterns along the ventral surface.

They have slender bodies, two dorsal fins, and narrow snouts. The hallmark feature is the dense array of photophores that emit blue-green light. In life, this bioluminescence provides counter-illumination camouflage in deeper waters and can aid in species recognition and signaling.

Etmopterus species are cosmopolitan, inhabiting temperate and tropical oceans from shelves to depths beyond 1,000 meters. They are typically mesopelagic, performing vertical migrations at dusk. Individual species show wide variation in depth range and habitat preference.

They are nocturnal predators, feeding on small fishes, crustaceans, and cephalopods. Reproduction is ovoviviparous, with females giving birth to live young after internal gestation. Litter sizes vary by species, ranging from a few to over a dozen pups.

Notable species include the dwarf lanternshark, Etmopterus perryi, one of the smallest sharks, reaching about 20–22 cm in length, and the spinax lanternshark, Etmopterus spinax, common in the North Atlantic.

Conservation: The status of Etmopterus species varies; many are data-deficient due to deep-water habitats, and some are affected by bycatch in deep-sea fisheries. Assessments by the IUCN cover only a portion of species.