Megachasmidae

Rare deepwater shark discovered in 1976

Megachasma is a genus of mackerel sharks. It is usually considered to be the sole genus in the family Megachasmidae, though suggestion has been made that it may belong in the family Cetorhinidae, of which the basking shark is the sole extant member. Megachasma is known from a single living species, Megachasma pelagios.