This taxonomic note formally describes the two taxa cited in the literature as ＇＇Gonyaulacysta sp. A DAVEY 1979＇＇ and ＇＇Gonyaulacysta sp. B DAVEY 1982＇＇ under the single name Daveya boresphaera gen. et sp. nov. Based on stratigraphical and palaeoecological considerations, both taxa are considered herein to express two phenotypic ornamental variations (formae A and B) of the same motile form. Daveya gen. nov. shows a gonyaulacacean paratabulation pattern and an S-type ventral organisation, combined with an A/ai arrangement. The parasuture 4＇/1＇ is clearly marked, a feature rarely observed within species displaying this type of ventral arrangement. A typical adherent operculum (P-3.), a thick, spongious, undifferentiated autophragm and a typical spherical shape distinguish Daveya gen. nov. from the genus Gonyaulacysta DEFLANDRE 1964 emend. SARJEANT 1982, Morphological characteristics of Daveya gen. nov. dictate its inclusion in the Gonyaulacoideae subfamily. The type species, Daveya boresphaera sp, nov., is a useful marker for the Upper Ryazanian of the European boreal province (British Isles, offshore North Sea, Denmark and Norwegian Sea). With regard to palaeoecological considerations already mentioned above, the new species Muderongia brevispinosa IOSIFOVA 1996 is considered to be a taxonomic junior synonym of Muderongia longicorna MONTEIL 1991, which is emended.