Figure 1

Light micrographs of the investigated warnowiid and polykrikoid taxa. (a)-(f) Images representing isolates 1 and 2 of 'Proterythropsis' sp. (a) Lateral view, median focus showing the large nucleus (n), the ocelloid (double arrowhead), and the posterior cell 'extension' (arrow). (b) Lateral view, showing the nematocysts (arrowheads). (c) Left ventral view showing the posterior cell 'extension' (arrow) and the ocelloid (double arrowhead). (d) Dividing cell with partly reassembled ocelloids/hyalosomes (double arrowheads) in the developing daughter cells. (e) Ocelloid. (f) Nematocysts. (g)-(i) Images representing the isolate of Warnowia sp. (British Columbia). (g) Lateral view of a free swimming cell showing the ocelloid (double arrowhead). (h) Lateral view of a cell in a hyaline cyst (arrow) showing the ocelloid (double arrowhead). (i) Dividing cell in a hyaline cyst (arrow) showing the ocelloids (double arrowheads). (j)-(k) Images showing the isolate of "Warnowia sp." (Florida) used for single cell PCR. (j) Ventral view, surface focus, showing the ocelloid (double arrowhead). (k) Mid cell focus showing the large nucleus (n). (l) An extruded nematocyst of Polykrikos kofoidii. (m)-(p) Images representing the two isolates of 'Nematodinium' sp. (m) Lateral to ventral view of a free swimming cell showing the large nucleus (n), the ocelloid (double arrowhead), and the brownish chloroplast color. (n) Lateral view of a cell in a hyaline cyst (arrow) showing the ocelloid (double arrowhead). (o) Dividing cell in a hyaline cyst (arrow). (p) Image showing recently divided daughter cells within the hyaline cyst (arrow). (q)-(r) Images of Erythropsidinium sp. showing the ocelloid (double arrowheads), and the piston (arrows). (s) Image representing the isolate of 'Pheopolykrikos' hartmannii showing the two large nuclei in the pseudo-colony. (t) Image representing the isolate of Polykrikos kofoidii undergoing division of the pseudo-colony. (u) Images of Polykrikos lebourae showing the two nuclei within the pseudo-colony. Scale bars 10 μm in (a)-(d), (g)-(i), (l)-(p), (t), (u), 20 μm in (j), (k), (q)-(s), 5 μm in (e), (f).