Preface to Class of Monoplacophora

Literal meaning: Bearing one plate

Common name: None
Shell: Members of this class have a single, cap-shaped shell similar to a limpet.

  • The apex of the shell is forward on the Monoplacophorans.
  • The shell is relatively small ranging in size from 3 to 30 mm in diameter.

    Animal: The animal body is composed of a head, a mantle and a large flattened foot.
  • Gills, nephrida, pedal retractor muscles and nerve connections are found in a pallial groove which surrounds the foot.
  • These organs repeat serially. They consist of six pairs of nephrida, five or six pairs of gills, and eight pairs of dorso-ventral pedal retractor muscles.
  • There are two pairs of gonads. No eyes or tentacles are present.

    Habitat: All species are marine.

  • Their range is limited to deep waters mostly in ocean trenches.

    Etc.: Monoplacophorans were thought to be extinct until 1952 when ten living specimens were dredged off the coasts of Costa Rica and Peru by the Galathea Expedition. At present, only a few living species are known to exist.

    Food: Unknown

    Reference: Class - Monoplacophora

    Ref. Keen, 1971 p 857
    Vaught, 1989 p viii,5