The megamouth shark was first discovered in 1976. The first known specimen was captured on November 15, 1976, after becoming entangled in the sea anchor of a United States Navy research vessel near Oahu, Hawaii. It was found at a depth of about 165 metres.
The 4.46-metre male weighed roughly 750 kilograms and initially puzzled researchers because it did not resemble any known shark. Ichthyologist Leighton Taylor examined it and helped establish that it represented a previously unknown species and even a new shark family, Megachasmidae.
Megamouths are one of only three living filter-feeding sharks, alongside whale sharks and basking sharks. They feed mainly on zooplankton, including krill, jellyfish and crustacean larvae, and are rarely seen because they generally inhabit deep water.
A common mix-up is confusing discovery with formal scientific description: the animal was caught in 1976, but the species was formally named Megachasma pelagios in 1983. Its rarity made the 1976 capture one of the major shark discoveries of the 20th century.