ena-STUDY-Seoul National University-09-04-2018-12:14:04:172-4042
GONYAULAX WHASEONGENSIS SP. NOV. (GONYAULES, DINOPHYCEAE), A NEW PHOTOTROPHIC SPECIES FROM KOREAN COASTAL WATERS
The planktonic phototrophic dinoflagellate Gonyaulax whaseongensis sp. nov. was isolated from the coastal waters off western Korea was described from living and fixed cells by LM and SEM, and the sequences of the rDNA were analyzed. G. whaseongensis had a plate formula of 2pr, 4', 6'', 6c, 6''', 1p, and 1'''' with S-type ventral organization like the other species in the genus Gonyaulax. However, this dinoflagellate had a narrow cingulum width, small displacement of the cingulum, slight overhang and steep angle between the ends of the cingulum, the quadrangular shape of sixth precingular plate, and reticulated cell surface without longitudinal lines or ridges, major keys used for speciation in the genus, which are clearly different from those of the other reported species in the genus. In addition, the SSU and LSU rDNA sequences of the new dinoflagellate were 8-11 % and 11-24%, respectively, different from those of Gonyaulax polygramma, Gonyaulax spinifera, Gonyaulax fragilis, Gonyaulax membranacea, and Gonyaulax digitale, the closest species. In the SSU and LSU phylogenetic trees, this species was clearly divergent from the clades consisting of G. spinifera, G. membranacea, and G. digitale, and also it was positioned at the basis of the clade consisting of G. polygramma and G. fragilis. Therefore, on the basis of morphological and phylogenetic criteria, we propose that this is a new species of the genus Gonyaulax.
The planktonic phototrophic dinoflagellate Gonyaulax whaseongensis sp. nov. was isolated from the coastal waters off western Korea was described from living and fixed cells by LM and SEM, and the sequences of the rDNA were analyzed. G. whaseongensis had a plate formula of 2pr, 4', 6'', 6c, 6''', 1p, and 1'''' with S-type ventral organization like the other species in the genus Gonyaulax. However, this dinoflagellate had a narrow cingulum width, small displacement of the cingulum, slight overhang and steep angle between the ends of the cingulum, the quadrangular shape of sixth precingular plate, and reticulated cell surface without longitudinal lines or ridges, major keys used for speciation in the genus, which are clearly different from those of the other reported species in the genus. In addition, the SSU and LSU rDNA sequences of the new dinoflagellate were 8-11 % and 11-24%, respectively, different from those of Gonyaulax polygramma, Gonyaulax spinifera, Gonyaulax fragilis, Gonyaulax membranacea, and Gonyaulax digitale, the closest species. In the SSU and LSU phylogenetic trees, this species was clearly divergent from the clades consisting of G. spinifera, G. membranacea, and G. digitale, and also it was positioned at the basis of the clade consisting of G. polygramma and G. fragilis. Therefore, on the basis of morphological and phylogenetic criteria, we propose that this is a new species of the genus Gonyaulax.