Chloroparva pannonica gen. et sp. nov. (Trebouxiophyceae, Chlorophyta) - a new picoplanktonic green alga from a turbid, shallow soda pan

We describe Chloroparva pannonica Somogyi, Felfoldi & Voros gen. et sp. nov., a new trebouxiophycean picoplanktonic alga isolated from a turbid, shallow soda pan in Hungary. The cells are spherical to oval, less than 2 mu m in diameter, with simple ultrastructure typical to small green algae. Cells divide by autosporulation, forming two daughter cells per autosporangium. Cell wall structure consists of an outer trilaminar layer, an inner microfibrillar layer and an electron-transparent layer covering the plasma membrane. The trilaminar layer of the mother cell wall often persists around the autospores. Typical chlorophyte pigments have been found, including chlorophyll a and b and lutein as the dominant carotenoid. The main fatty acid was oleic acid. The phylogenetic position of the new chlorophyte confirms the proposal of a new genus within the Trebouxiophyceae. Based on its 18S rRNA gene sequence, this isolate is distantly related to Nannochloris eucaryotum UTEX 2502, Chlorella minutissima C-1.1.9 and C. minutissima SAG 1.80 (<= 97.6% 18S rRNA gene pairwise similarities).