The world’s smallest known shark, the Dwarf Lanternshark, is a fascinating creature of the deep sea. Often no larger than a human hand, it possesses all the defining characteristics of its larger shark relatives, including a cartilaginous skeleton, multiple gill slits, and rows of sharp teeth.
The Dwarf Lanternshark
The Dwarf Lanternshark, scientifically known as Etmopterus perryi, belongs to the dogfish shark family, Etmopteridae. This species is the smallest shark globally, reaching a maximum length of about 20 centimeters (7.9 inches). Adult males mature at around 16 to 17.5 centimeters (6.3 to 6.9 inches), while females mature from about 15.5 centimeters (6.1 inches), with pregnant individuals known up to 20 centimeters (7.9 inches) long.
This shark features a slender, cigar-shaped body with a dark brown coloration. Its head is notably long, wide, and flattened. The eyes are large, a common adaptation for creatures living in low-light environments. It has two dorsal fins, each with a spine, and lacks an anal fin. The skin is covered in thin, needle-like dermal denticles. A distinctive pattern of black markings adorns its ventral surface, along with a fine black line running along the middle of its back.
American ichthyologists Stewart Springer and George H. Burgess formally described the Dwarf Lanternshark in 1985. They described the species from specimens collected in 1964 by the U.S. Fish and Wildlife Service research ship Oregon. The initial discovery site was in the Caribbean Sea off the coast of Colombia, at depths around 290 meters (950 feet).
Its Underwater World
The Dwarf Lanternshark inhabits the upper continental slopes of the Caribbean Sea, specifically off the coasts of Colombia and Venezuela. It is found at depths ranging from 283 to 439 meters (928 to 1,440 feet). This deep-sea environment is characterized by perpetual darkness, cold temperatures, and high pressure.
The Dwarf Lanternshark is a carnivore, preying on small organisms. Its diet primarily consists of miniature crustaceans like krill, small fish, and cephalopods such as squid. Little is known about its specific behaviors.
The species primarily occupies the bathypelagic zone, an area where sunlight does not penetrate. While generally associated with the Caribbean, some research suggests a wider distribution, potentially including the Pacific Ocean near the Hawaiian Islands, though more study is needed to confirm its full range.
Remarkable Features
The Dwarf Lanternshark produces light, a phenomenon known as bioluminescence. This light is produced by specialized light-producing organs called photophores, present on its belly and fins. These photophores emit a soft glow in the dark ocean environment.
This bioluminescence serves several purposes. One primary function is counter-illumination, where the light produced on its ventral side helps it camouflage against any residual light filtering down from the surface. This effectively hides its silhouette from potential predators lurking below. In the deeper, darker waters, its light production is theorized to also attract smaller prey, drawing them closer to the shark.
The Dwarf Lanternshark reproduces through aplacental viviparity, meaning the eggs hatch inside the mother’s body, and the developing young are nourished by a yolk sac until birth. Females give birth to small litters of two or three live pups. These pups are small at birth, measuring approximately 5.5 to 6.0 centimeters (2.2 to 2.4 inches) long.