New species of the dinoflagellate cyst genus <i>Svalbardella</i> Manum, 1960, emend. from the Paleogene and Neogene of the northern high to middle latitudes

<p>Species of the fusiform peridiniacean dinoflagellate cyst genera <i>Svalbardella</i> Manum, 1960, emend. (Eocene–Oligocene) and <i>Palaeocystodinium</i> Alberti, 1961 (Late Cretaceous–Miocene), have been examined from the high to middle latitudes of the Northern Hemisphere: Spitsbergen, Norwegian-Greenland Sea, Labrador Sea, western North Atlantic, and the North Sea basin. The genus <i>Svalbardella</i> is emended to comprise species with smooth or finely ornamented surfaces and for which one or both horns are bluntly rounded. <i>Svalbardella clausii</i> sp. nov. has a narrow range restricted to the lowermost Chattian (close to the NP24–NP25 boundary and within Chron C9n), and it therefore appears a useful stratigraphical marker. This species has a wide distribution across the North Atlantic, having been reported from the North Sea basin, western North Atlantic, and the Labrador Sea. <i>Svalbardella clausii</i> sp. nov. overlaps stratigraphically with the reoccurrence interval of <i>Svalbardella cooksoniae</i> Manum, 1960, and spans the Oi-2b cooling maximum. Its presence may therefore be related to the establishment of cooler surface waters at this time.<i> Svalbardella kareniae</i> sp. nov. has a discordant occurrence: Lower Oligocene and Lower Miocene of the Norwegian Sea at Deep Sea Drilling Project Site 338 and Ocean Drilling Program Site 643, respectively, and mid-Oligocene of the North Sea. Its distribution suggests that <i>Svalbardella kareniae</i> sp. nov. favours more open marine conditions. <i>Palaeocystodinium obesum</i> Fensome et al., 2009, described from offshore eastern Canada where it has a highest occurrence in the Lower Oligocene, is emended to include specimens with a finely ornamented periphragm and traces of tabulation in addition to the archeopyle.</p>