ETMOPTERIDAE LANTERN SHARKS
The Etmopteridae or Lantern sharks are a family belonging to the order of Squaliform sharks. There are more than 50 species within 5 genera. They occur worldwide in deep water. Some have very wide ranges, and some are endemic. Within this family, many species have been more recently discovered, and species are still being discovered. Some species of sharks in this family are some of the smallest known sharks when mature, like the Cylindrical Lanternshark and Dwarf Lanternshark. Check out our World’s Smallest Sharks article here. These sharks also give birth to live young, and some as small as 10-20 cm. The sharks belonging to this family of Lantern sharks are ovoviviparous and have anywhere from 3-20 pups per litter.
The sharks in the family Etmopteridae are dwarf to moderate sized, with mature adults ranging from 10 cm-3.5 feet on average. Many of the species belonging to this family of Lantern sharks are special because they possess photophores. Check out our Glow in the Dark Sharks article here.
There are some typical traits across all genre. Some have visible and not so visible black marks on the abdomen, flanks and tail. There are two dorsal fins with strongly grooved spines. It is typical in this family for the second spine to be larger than the first dorsal fin spine. There is no anal fin. There are no precaudal pits or lateral keels on the caudal peduncle.
Centroscyllium have short to somewhat long snouts. Their teeth are comblike. They have cusps and cusplets in both jaws. The teeth in Aculeola are small and hook-like in both jaws. Trigonognathus and Miroscyllium have extremely distinctive teeth.
Etmopterus typically have dark markings ventrally which typically indicate photophores. The upper teeth of Etmopterus also have a cusp and one or more pairs of cusplets. Their lower teeth are very different from the upper teeth, and are blade-like. Some species have lines of dermal denticles along their flanks and dorsal surface this has been described as an engraved look.
It has been noted that upon retrieval of many specimens, they have been in very poor condition due to vigorous damage from fishing gear. Therefore, visual identification is a challenge which results in many misidentifications. In some cases, the only way to accurately identify these species from one another is by examining all details from dentation, dermal denticles, photophores, coloration and several other features including vertebra and DNA tests.
Most species within this family live in deep water and are bottom-dwelling between 656-4,921 feet. Their typical range is 164-14,764 feet. There are some species that are considered semi-oceanic. Some of these species are social and form small to large aggregations, schools or shoals.
Most species in this family are common, but poorly known. Most are not considered valuable by commercial fishing, and are typically discarded as bycatch.