Obliquicauda gen. nov. (Trebouxiophyceae, Chlorophyta), including O. inflata sp. nov. and O. apiculata sp. nov.: foliicolous algae from Ficus leaves

Two unidentified foliicolous algal strains were isolated from living Ficus leaves in a tropical rainforest of China. Morphological, ultrastructural, and molecular phylogenetic investigations of these strains indicated that they differ from each other but cluster together and represent a new lineage of Trebouxiophyceae in the Choricystis/Botryococcus clade. These strains had similar morphologies with solitary, fusiform, and slightly asymmetrical vegetative cells, a basal stalk, and smooth cell walls. Cells contained a single parietal chloroplast with a pyrenoid surrounded by several starch sheaths and penetrating thylakoids. Asexual reproduction occurred in both strains through the splitting of the mother cell wall into two autospores. Phylogenetic analysis based on 18S, ITS and rbcL showed the two strains as a distinct branch in the Choricystis/Botryococcus clade of the Trebouxiophyceae. Here, we describe the two strains as the new genus, Obliquicauda gen. nov., and two new species, Obliquicauda inflata sp. nov. and Obliquicauda apiculata sp. nov.