Physeteroidea is a
superfamily that, today, includes three
extant species of
whales; the
sperm whale, in the genus
Physeter, and the
pygmy sperm whale and
dwarf sperm whale, in the genus
Kogia. In the past, these genera have sometimes been united in a single family, the
Physeteridae, with the two
Kogia species in a subfamily (Kogiinae); however, recent practice is to allocate the genus
Kogia to its own family, the
Kogiidae, leaving the Physeteridae as a
monotypic (single extant species) family, although additional fossil representatives of both families are known.
