The extant thermophilic dinoflagellate Tectatodinium pellitum (al. Tectatodinium rugulatum) from the Danian of Denmark

Tectatodinium rugulatum (Hansen, 1977) McMinn, 1988, from the lower Danian of Denmark, is considered conspecific with, and a junior synonym of, the extant thermophilic species Tectatodinium pellitum Wall, 1967. However, the Danian material, based on holotype and topotype specimens, appears to show a degree of morphologic variability not seen in younger material. The accepted stratigraphic range base of Tectatodinium pellitum is now extended to the lower Danian, where this species appears to be a useful biostratigraphic marker in the Danish North Sea basin.