<i>Phelodinium fensomei</i> sp. nov.: a protoperidineacean dinoflagellate cyst from the lower Paleocene (Danian) of the Oyster Bay Formation, Vancouver Island, Canada

Phelodinium fensomei is a new species of organic-walled dinoflagellate cyst described from the Appian Way section of the Oyster Bay Formation, Vancouver Island, British Columbia, Canada. Phelodinium fensomei sp. nov. differs from other species of Phelodinium in its unique combination of characters including an elongate epicyst, bilobate endocyst antapex, and microgranulate to verrucate surface ornamentation. The species occurs exclusively within Dinoflagellate Cyst Zone D4 of the Oyster Bay Formation along with the Danian indicator taxon Danea californica. This is also the first study to perform scanning electron microscopy and epifluorescence analysis on a specimen belonging to the protoperidinioid genus Phelodinium, revealing minute features and a negative response to ultraviolet light exposure, indicating a heterotrophic feeding strategy for the motile cell. Although P. fensomei sp. nov. occurs at markedly low relative and absolute abundances in the examined interval, it is restricted to strata of Danian age suggesting potential biostratigraphic utility.