The (Somniosus pacificus) a sleeper shark of the family Somniosidae, measuring up to in length, although it could possibly reach lengths in excess of .

The southern sleeper shark, or Whitley's sleeper shark (Somniosus antarcticus), is a deepwater benthopelagic sleeper shark of the family Somniosidae found in the southern and subantarctic extremes of the Atlantic, Indian and Pacific Oceans, and some northern reaches of the Antarctic oceans.