Coccolithophorids in Polar Waters: Pappomonas spp. Revisited

摘要

A contingent of weakly calcified coccolithophorid genera and species were described from polar regions almost 40 years ago. In the interim period a few additional findings have been reported enlarging the realm of some of the species. The genus Pappomonas is revisited here with the purpose of providing, based on additional sampling from both polar regions, an update on species morphology, life history aspects and biogeography that can serve as a reference for the future. The examination of a substantial number of cells unequivocally supports the elevation to species level of P. borealis stat. nov. (previously referred to as P. flabellifera var. borealis) as a separate taxon which is different from P. flabellifera in a number of critical morphological features. Additional evidence in favour of linking P. virgulosa and Balaniger balticus in a shared life history in combination with significant differences in coccolith morphology between the Pappomonas type species (P. flabellifera) and P. virgulosa has prompted us to synonymise Balaniger balticus with Pappomonas virgulosa, while informally keeping the names of the phases as Balaniger virgulosa HET (= Pappomonas virgulosa phase) and Balaniger virgulosa HOL (= Balaniger balticus phase). A new species, Pappomonas garrisonii sp. nov. is described to accommodate Antarctic material from the Weddell Sea. While fitting into the Pappomonas generic concept, the species adds new dimensions to the overall appearance of the coccolith armour of the cell and emphasizes the close relationship between species of Pappomonas and Papposphaera.