Brygmophyseter is an extinct genus of toothed whale in the sperm whale family with one species, B. shigensis. When first described, this species was placed in an extinct form genus Scaldicetus of toothed whales, as S. shigensis. In 2006, two new genus names were independently created for the species: Naganocetus and Brygmophyseter. Since Brygmophyseter was published first, Naganocetus became a junior synonym.