Heteromorphic Life Histories in Arctic Coccolithophorids (Prymnesiophyceae)1

During three visits to Disko Bay, West Greenland, we found four different types of prymnesiophyte flagellates with heterococcoliths from species of the generaPapposphaeraTangen andPappomonasManton and Oates in characteristic and consistent combinations with holococcoliths from species of the generaTurrisphaeraManton, Sutherland, and Oates andTrigonaspisThomsen. We conclude that several taxa previously considered to be autonomous species are, in fact, part of life histories combining hetero‐ and holococcolithophorid forms in a manner somewhat similar to that known from studies of cultured strainsof Coccolithus pelagicus(Wallich) Schiller andCrystallolithus hyalinus(Gaarder) Markali. Similarly,CalciarcusManton, Sutherland and Oates andWigwammaManton, Sutherland and Oates also may be alternate phases of a coccolithophorid life history.