Two species of peridinioid dinoflagellate cyst are described from Late Quaternary lacustrine and fluvial deposits in England and Scotland. Saeptodinium skipseaense sp. nov. has a bipesoid tabulation and a hemiepicystal archaeopyle. Colonsaydinium psilatum gen. et sp. nov. has a compound archaeopyle interpreted as 2̅1̅3̅P̅ (1–2i 3–5″). The morphology of the archaeopyle suggests that this may be the cyst of a species with cinctoid tabulation. Both taxa are found only in sediment laid down in base-rich, non-turbulent, relatively deep fresh water.
- © 1985 The Micropalaeontological Society