Morphology and phylogeny of a new woloszynskioid dinoflagellate Tovellia paldangensis sp nov (Dinophyceae)

Abstract

The genus Tovellia contains approximately eight described species. A new species, Tovellia paldangensis sp. nov. was observed by incubation of a cyst from sediment collected in the Paldang Dam Lake in Korea. The vegetative cells of this new species were 20.0-27.0 mu m long, 18.0-23.0 mu m wide, and 17.0-20.5 mu m thick. The cingulum was displaced by one cingulum width, the nucleus was located in the posterior part of the cell, and the chloroplasts were numerous and in yellow-green in color. A prominent red body was present on each side of the cingulum. The amphiesma had numerous thin polygonal plates that were arranged in three to four latitudinal series on the epicone and in two to three series on the hypocone. A narrow apical line of plates (ALP) extended over the anterior part of the cell, approximately in a 3/4 of the ventral side and 1/4 of the dorsal side of the epicone. The antapical plate was usually hexagonal. T. paldangensis was clearly differentiated from the other species of Tovellia by the morphology of its vegetative cell (two red bodies, and the ALP lines on each side separated by a row of four to five elongate plates) and the resting cyst (typically covered with numerous short solid spines). Phylogenetic analysis based on partial large subunit ribosomal RNA gene sequences indicated that T. paldangensis was most closely related to T. coronata, T. sanguinea, and T. aveirensis.