Redefinition of the Dinoflagellate Genus Alexandrium Based on Centrodinium: Reinstatement of Gessnerium and Protogonyaulax, and Episemicolon gen. nov. (Gonyaulacales, Dinophyceae)

Figure 1

Light (a–j) and scanning electron (l–s) micrographs of Centrodinium punctatum. (a) Plankton sample with Centrodinium spp. The arrows point the cells of C. punctatum. (b–c) Individuals used for molecular analyses. (d) Partially dissociated theca in ventral view. (e–f) Epitheca. The insets show the first postcingular plate and the posterior sulcal plate. (g) Right-ventral face. The inset shows the right antapex. (h) Left-ventral view. The inset shows the dorsal antapex. (i) Ventral view of the sulcal area. (j-k) Dissociated sulcal plates. (l) Left-ventral view. (m) Left antapex. (n) Left face. (o) Right face. (p) Ventral view. (q) Apical view. (r–s) Apex. 1′–4′ = apical plates; 1′′–6′′ = precingular plates; 1′′′–5′′′ = postcingular plates; 1′′′′–2′′′′ = antapical plates; C1–C6 = cingular plates; c.p.  = closing, cover platelet or canopy; mp = marginal pores surrounding the apical pore plate; Po = apical pore plate; S.a. = anterior sulcal plate; s.a.p. = pore of the anterior sulcal plate; S.d.a. = right (dexter) anterior lateral sulcal; S.d.p. = right posterior lateral sulcal; S.m.a. = anterior median sulcal; S.m.p. = posterior median sulcal; S.p. = posterior sulcal plate. S.s.a. = left (sinister) anterior lateral sulcal; S.s.p. = left posterior lateral sulcal. Scale bars (a–q) = 20 μm, (r–s) = 2 μm.