A new, sighted species of the ostracod genus Poseidonamicus (P. panopsus sp. nov.) is recorded living on the continental shelf and upper slope off south-western Africa in water depths between 120 m and 545 m. All previous records of the genus have been from water depths greater than 1 km. The discovery indicates that sighted species survived, in shallow-water, from the late Cretaceous/early Tertiary stocks when the genus originated in the SW Pacific area. The habitat of the new species is defined in terms of temperature, salinity, and dissolved oxygen values within the Antarctic Intermediate Water mass, where it forms part of the Benguela system, and associated cells of intense upwelling.