Eustigmatophytes are a small group (7 genera; ~12 species) of eukaryotic algae that includes marine, freshwater and soil-living species[2]. All eustigmatophytes are unicellular, with coccoid cells and polysaccharide cell walls. Eustigmatophytes contain one or more yellow-green chloroplasts, which contain chlorophyll a and the accessory pigments violaxanthin and β-carotene. Eustigmatophyte zoids (gametes) possess a single or pair of flagella, originating from the apex of the cell. Unlike other heterokontophytes, eustigmatophyte zoids do not have typical photoreceptive organelles (or eyespot); instead, an orange-red eyespot outside of a chloroplast is located at the anterior end of the zoid. In terms of ecology, eustigmatophytes occur as photosynthetic autotrophs across a range of systems. Most eustigmatophyte genera live in freshwater or in soil, although Nannochloropsis contains marine species of picophytoplankton (2 → 4 μm). [edit] See also [edit] References | SAR: Chromalveolata: Heterokont | | Ochrophyta/ (photosynthetic) | | | | | | | | | | | | | | | Biddulphiophycidae ( Eupodiscaceae, Odontella, Biddulphia) · Chaetocerotophycidae ( Attheya, Bacteriastrum, Chaetoceros) · Corethrophycidae ( Corethron) · Coscinodiscophycidae ( Hyalodiscus, Podosira, Coscinodiscus, Planktoniella, Stellarima, Melosira, Stephanopyxis, Paralia) · Cymatosirophycidae ( Cymatosira) · Lithodesmiophycidae ( Lithodesmium) · Rhizosoleniophycidae ( Guinardia, Proboscia, Rhizosolenia) · Thalassiosirophycidae ( Thalassiosira) | | | | | | | | | | | | | Fungus-like/ (nonphotosynthetic) | | | |