THE STRATIGRAPHIC IMPORTANCE OF SPECIES OF SUMATRADINIUM, BARSSIDINIUM, AND ERYMNODINIUM, NEOGENE DINOFLAGELLATE GENERA FROM OFFSHORE EASTERN CANADA

The Neogene strata of offshore eastern Canada contain a rich diversity of dinoflagellate cysts. Among the most distinctive are species of th e peridinialean genus Sumatradinium and the related genera Barssidiniu m gen.nov. and Erymnodinium gen.nov. Sumatradinium and Erymnodinium ha ve a reticulate wall, whereas Barssidinium has a smooth to granulate w all. Sumatradinium and Barssidinium have processes or pustules only; E rymnodinium has crests. The three genera and their constituent species are useful for biostratigraphic subdivision in the Miocene and Plioce ne, as exemplified in the two wells Evangeline H-98 and Heron H-73; st ratigraphic control for these wells is based on previously established palynologic data. To categorize the considerable morphological variat ion of these genera and promote their biostratigraphic usefulness, we propose five new species: Sumatradinium druggii, Sumatradinium pustulo sum, Barssidinium evangelineae, Barssidinium graminosum, and Barssidin ium wrennii. We also emend the generic diagnosis of Sumatradinium and the specific diagnosis of Sumatradinium hispidum.