The Maastrichtian chalks of Denmark and the Danish North Sea contain a new gonyaulacoid dinoflagellate cyst,Glaphyrosphaera glabragen. et sp. nov. The new genus is holocavate and laterally compressed with precingular archeopyle, type P (3″) and is unique in having a funnelshaped process which connects the peri-and endophragm in the sulcal areas. The new genus is currently monotypic and restricted to the Maastrichtian Stage.