What is the world's smallest species of shark by length?

The world's smallest species of shark by length is the dwarf lanternshark, also known as the Etmopterus perryi. The dwarf lanternshark is a deepwater shark that inhabits the waters off the coast of Colombia and Venezuela in South America. It was discovered in 1964 and is only about 8 inches long, making it one of the smallest sharks in the world.

The dwarf lanternshark has a slender body and a long, pointed snout. It is black or brown in color with small, light-producing organs called photophores covering its body. These photophores allow the shark to emit light, making it easier for the shark to communicate with other sharks, attract prey, and avoid predators.

Despite its small size, the dwarf lanternshark is a fascinating and important species. Like many deepwater species, it faces threats from human activities such as deep-sea fishing and oil drilling. Conservation efforts are underway to protect this and other vulnerable species from further harm.

The world's smallest species of shark by length is the dwarf lanternshark (Etmopterus perryi). It is a species of dogfish shark in the family Etmopteridae and is the smallest shark in the world, reaching a maximum known length of 20 cm (8 in). It is known to be present only on the upper continental slopes off Colombia and Venezuela, at a depth of 283–439 m (928–1,440 ft). This species can be identified by its small size at maturity, long flattened head, and pattern of black ventral markings and a mid-dorsal line. Like other members of its genus, it is capable of producing light from a distinctive array of photophores.