Dwarf lantern shark (Photo: Wikimedia Commons)
The dwarf lantern shark is among the smallest species of fish in the world. The name of the shark comes from the fact that they are a small (dwarf) shark and are bioluminescent (lantern) in the dark environment of the deep sea level (Benthic zone) where they dwell. The Dwarf lantern shark was recently discovered in 1964.
They rarely swim out of their ecological niche under the sea between depths of 660 and 8000 feet, which makes the species difficult to catch and observe. It is unknown if they are an endangered species. According to the International Union for Conservation of Nature (IUCN), the dwarf lantern shark has been labeled as data deficient, meaning there is not enough research on this species of fish to adequately assess their status.
The lifespan of the dwarf lantern shark is estimated between 20-30 years. Dwarf lantern sharks are often targeted by parasites which shorten the lifespan of these creatures. The dwarf lantern shark belongs to the dog shark family ‘etmopteridae,’ and is the smallest species in this family. The scientific name of this fish species is Etmopterus perryi derived from a notable shark expert Perry Gilbert.
Morphology
Dwarf lantern shark fish is an exceedingly small fish when compared to other fish species in the dogfish family. The whole length of the dwarf lantern fish is between 6 to 8 inches in length (with some claimed to grow up to 18 inches), the young sharks can be as small as 2.2 to 2.4 inches at birth. Due to this small length, it is possible to place the dwarf lantern shark on the palm. The biggest part of its body is a flattened head that occupies about one-third of the entire body. Also, it has big bulbous eyes that enable it to navigate in the dark environment under the sea. The dwarf lantern shark is generally dark brown in the dorsal region, while the ventral region color is a velvety black that is bioluminescent. The total number of teeth of the dwarf lantern shark is between 50 and 57, that is, it has between 20 to 23 teeth in the upper jaw, and 30 to 34 teeth in the lower jaw. The dwarf lantern shark teeth are designed for cutting and slicing. Among the dwarf lantern shark, the female species are generally bigger than the males.
Adaptation
The ventral side of the fish’s body is covered with black markings, and some of these markings (photophores) glows, and another marking on the pelvic fin emit chromatophores that assist the fish in blending into its environment. These photophores and chromatophores help the fish in adapting to the environment, as the photophores are used for camouflage during feeding in shallow waters to escape the attention of predators, as well as in attracting smaller fish to feed upon. The Dwarf lantern shark like other members of the shark family is a carnivore that basically feeds on Krill, shrimp, zooplankton, as well as smaller fish.
Habitat
Because the fish is rarely found on the surface of the water, it is believed they resided in the deepest parts of the ocean, majorly in the benthic zone. The Dwarf lantern shark is the smallest of the seven known species of lantern sharks. This shark has only been discovered in the Caribbean Sea. It lives at a depth of 1000 to 1500 feet near the coast of South America. Because of their small size, dwarf lantern sharks are not on the target of fishermen. However, they can be accidentally captured during a big fishing operation in the ocean.
Reproduction
They have a viviparous mode of reproduction, that is, their eggs hatch within the female. They generally have a low rate of reproduction giving birth to 2 to 3 pups at a time. The young hatch from eggs within the mother’s body and are nourished by a yolk sac until birth. The young sharks are bioluminescent before they are born, because the yolk sac is florescent even before any photophores are formed. This led to the assumption that the luminescent materials are transferred to the offspring from the mother. Sexual maturity of dwarf lantern sharks depends on the body length. Males become ready to reproduce when they reach a length of 6.3 to 6.9 inches, while females begin mating once they reach a length of 6.1 inches.
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Lanternshark Photos
References
AnimalSake (2017, August 12). You’d Never Imagine These 17 Facts About the Dwarf Lanternshark. Retrieved from https://animalsake.com/facts-about-dwarf-lanternshark
IP Factly (2013, March 13). Lantern Shark Facts. Retrieved from http://ipfactly.com/lanternshark/
Smithsonian (2019). Dwarf Lantern Shark. Retrieved from https://ocean.si.edu/ocean-life/sharks-rays/dwarf-lantern-shark