New dinoflagellate cyst and acritarch taxa from the Pliocene and Pleistocene of the eastern North Atlantic (DSDP Site 610)

A palynotogical study of Pliocene and Pleistocene deposits from DSDP Hole 610A in the eastern North Atlantic has revealed the presence of several new organic-walled dinoflagellate cyst taxa. Impagidinium cantabrigiense sp. nov. first appeared in the latest Pliocene, within an interval characterised by a paucity of new dinoflagellate cyst species. Operculodinium? eirikianum var. crebrum var. nov. is mostly restricted to a narrow interval near the Mammoth Subchron within the Pliocene (Piacenzian Stage) and may be a morphological adaptation to the changing climate at that time. An unusual morphotype of Melitasphaeridium choanophorum (Deflandre & Cookson, 1955) Harland & Hill, 1979 characterised by a perforated cyst wall is also documented. In addition, the stratigraphic utility of small acritarchs in the late Cenozoic of the northern North Atlantic region is emphasised and three stratigraphically restricted acritarchs Cymatiosphaera latisepta sp. nov., Lavradosphaera crista gen. et sp. nov. and Lavradosphaera lucifer gen. et sp. nov. are formally described.