Picocystis salinarum gen. et sp nov (Chlorophyta) - a new picoplanktonic green alga

We describe Picocystis salinarum R.A. Lewin, gen. ef sp. nov., a hitherto u nrecognized kind of green picoplanktonic al,aa from a saline pond, now isol ated in pure culture. The cells are normally spherical or oval. 2-3 mum in diameter, but tend towards a trilobed shape under conditions of nutrient de pletion. The ultrastructure is typical far green algae. The pigment complem ent comprises chlorophylls a and b and the carotenoids neoxanthin, violaxan thin, alloxanthin, monadoxanthin, diatoxanthin, lutein and zeaxanthin. The major component of the cell wall is polyarabinose. Such a unique combinatio n of features suggests that this alga might be assigned to a new lineage wi thin the Chlorophyta.