two unequal flagella, the longer flagellum twice cell length
single chloroplast, twisted, brown-yellowish, without pyrenoid
cell surface with conspicuous blisters (mucocysts)
nucleus in anterior third
I have found Ochromonas crenata so far only in the Simmelried, mostly associated with Ochromonas verrucosa. While Ochromonas verrucosa is oval and the cells are mostly longer than 20 µm, Ochromonas crenata has a round body shape and is clearly smaller than 20 µm (mostly about 15 µm). In addition, the longer flagellum of Ochromonas crenata is proportionally much longer than that of Ochromonas verrucosa. The small blisters on the cell surface are mucocysts.
Fig. 1 a-e: Ochromonas crenata. L = 15 µm. A freely swimming specimen. BL = blisters (mucocysts), F = flagellum (the longer one), Nu = nucleus. Obj. 100 X.