Malvinia escutiana, a new biostratigraphically important Oligocene dinoflagellate cyst from the Southern Ocean

► We describe an unusual dinocyst from the Southern Ocean. ► We name this dinocyst species Malvinia escutiana. ► Available biostratigraphic information points out that Malvinia escutiana originated in conjunction with the onset of major Antarctic glaciation during the Eocene-Oligocene Transition (~ 34 Ma). ► Malvinia escutiana may be an important biostratigraphic marker for the Eocene-Oligocene Transition in the Southern Ocean.