Neopilina galatheae

Neopilina galatheae is a species of monoplacophoran, a superficially limpet-like marine mollusc. Its name means new Pilina (after Pilina, an extinct Monoplacophore that lived about 400 million years ago).
It was discovered off the Pacific coast of Costa Rica in the 1950s, where 10 specimens were collected. Later, additional specimens have been collected off the coast of Chile and off Cabo San Lucas, Baja California, Mexico.
Its discovery has been described as "the most dramatic one in the history of malacology." 