Karenia cristata sp nov and Karenia bicuneiformis sp nov (Gymnodiniales, Dinophyceae):: two new Karenia species from the South African coast

In 1988 and 1989, an undescribed gymnodinioid dinoflagellate species turned the waters of the largest bay in South Africa, False Bay, to a dirty olive-green colour. The bloom was accompanied by extensive abalone (Haliotis midae) mortalities and noxious gases causing eye, nose, skin and throat irritations in humans. In 1995, another undescribed gymnodinioid species bloomed in the same bay but with no adverse effects on marine fauna or humans. These two species form an established component of the phytoplankton assemblage on the south coast of South Africa. They are described here as Karenia cristata Botes, Sym & Pitcher and K. bicuneiformis Botes, Sym & Pitcher. Karenia cristata has a straight apical groove elevated into an apical crest and extending down immediately to the right of the sulcal extension on the ventral side. The hypocone is asymmetrical, with the right lobe larger and more rounded than the left; the nucleus is central, with the bulk situated in the hypocone. Its pigment content is similar to that of K. mikimotoi and K. brevis. Other than K. brevis, K. bicuneiformis is significantly larger than the other Karenia species and is distinctly dorso-ventrally flattened. The hypocone is w-shaped and the epicone is conical, giving the cell a distinctly angular outline. Pairwise distance comparisons of partial large subunit (28S) rDNA sequences indicate that these two species are clearly different from other species within the genus.