Taxonomic reassessment of strains formerly classified as chloromonas insignis (Volvocales, chlorophyceae) and description of Gloeomonas anomalipyrenoides sp. nov.

Two strains previously identified as Chloromonas insignis, NIES-447 and ACOI-3241, and two new strains related to NIES-447 were examined using light microscopy. The molecular phylogeny of their 18S rRNA gene sequences were also examined, and their identifications are reassessed. The strains represent two independent species, both of which can be distinguished from Chloromonas insignis. Strain NIES-447 and the two new strains each have large, irregular atypical pyrenoids without associated starch granules. They are described here as Gloeomonas anomalipyrenoides Nakada et al. sp. nov. Strain ACOI-3241, which has small atypical pyrenoids on the tips of the chloroplast lobes, was identified as C. vernalis (Skuja) Nakada comb. nov. The identity of the three strains of G. anomalipyrenoides was verified by their identical ITS-2 rDNA sequences. Both G. anomalipyrenoides and C. vernalis of the clade Chloromonadinia in the Volvocales (Chlorophyceae) are closely related to other species of Gloeomonas and to C. kasaiae Matsuzaki, Nakada, Y. Hara & Nozaki, respectively.