megamouth shark
Scientists performed a public autopsy of the megamouth shark in Shizuoka City. YouTube

An extremely rare megamouth shark has been caught off the coast of Japan – believed to be only the 58<sup>th sighting of the alien-looking creature in history.

The shark was caught last month and over 1,000 people gathered at a museum in Shizuoka City to watch a public autopsy.

Megamouth sharks are named because of their huge heads and mouths. The shark was caught at a depth of around 2,600ft.

While the creature has been spotted in oceans across the world, at least 13 have been in waters off Japan's coast.

The megamouth shark measured 13ft in length and weighed around 1,500lbs. It is now on public display at the Marine Science Museum in Shizuoka, The Japan Daily Press reported.

Facts about megamouth sharks

Megamouth sharks, or Megachasma pelagios, come from the Lamniformes order of sharks commonly known as mackerel sharks, which includes the great white shark.

The first specimen was caught in 1976 and the largest known megamouth measured 18.4ft in length.

Megamouths are the third known species of planktonivorous shark, the other two being the whale shark and basking shark. Their diet mainly consists of plankton, small shrimps and jellyfish.

While they mainly live deep in the ocean, they come the surface to feed at night.

It is thought they move slowly and has been observed being attacked by sperm whales, Discovery UK reports.

As well as Japan, megamouths have been caught off the coasts of Senegal, South Africa, Brazil, Indonesia, the Philippines, Thailand and California.