Insights into the Taxonomy of the Genus Chrysastrella (Chrysophyceae), with Establishment of Chrysastrellaceae fam. nov.

Chrysastrella is a small genus of the Ochromonas-like chrysophytes, taxonomy and phylogenetic placement of which remained unclear. For a long time Chrysastrella was considered a cyst genus, i.e., a morphogenus based on the structure of stomatocysts, the resting stages of chrysophytes. We isolated several new strains of C. paradoxa from the peat bogs in Murmansk Region and the Republic of Komi (Russia) and studied them using light and scanning electron microscopy as well as molecular techniques. We showed that morphological differences between C. paradoxa, C. minor and C. breviappendiculata are within the range of variability of stomatocysts during development. So, we synonymized C. minor and C. breviappendiculata with C. paradoxa. Molecular phylogenetic analysis based on SSU rDNA and rbcL sequences revealed that Chrysastrella belongs to the order Chrysosaccales. A new monotypic family, Chrysastrellaceae fam. nov., was formally described to accommodate this genus.