Genus Ostreopsis Schmidt, 1902
Cells armoured. Cells medium to large; anterio-posteriorly compressed. In apical view, tear-shaped tapering ventrally. Apex displaced to the dorsal surface, left side. Cingulum not descending and epitheca not noticeably smaller than hypotheca in apical view. Ventral pore (Vp) and ridged plate (Rp) present between 1 and 7 plates. Characteristic Po with slit. Plate formula: Po, 3', 7, 6c, > 6s, Vp, Rp, 5''', 1p, 2''''. Chloroplasts present.
Warm water benthic species; some toxin producers.
Species included from this genus:
Ostreopsis heptagona Norris et al., 1985
Ostreopsis labens Faust and Morton, 1995
Ostreopsis lenticularis Fukuyo, 1981
Ostreopsis mascarenensis Quod, 1994
Ostreopsis ovata Fukuyo, 1981
Ostreopsis siamensis Schmidt, 1902