Abstract
Two strains, NIES-2215 and NIES-2243, have been labeled “Chlamydomonas (Cd.) gerloffii” and “Cd. subangulosa,” respectively. Although these two strains were previously suggested to belong to the Reticulata group of the genus Chloromonas (Cr.), detailed taxonomic examinations are lacking for both strains. Here we taxonomically re-examined the two strains based on light and transmission electron microscopy and molecular phylogenetic analysis using a combined dataset from 18S and 28S ribosomal RNA gene sequences and genes encoding ATP synthase β-subunit, P700 chlorophyll a-apoprotein A1 and P700 chlorophyll a-apoprotein A2. The “Cd. gerloffii” strain NIES-2215 differed from all other species of the Reticulata group in terms of phylogeny and ultrastructure of the pyrenoid and eyespot; it was morphologically identified as Cd. gerloffii. Thus, we propose Cr. difformis Tomo. Makino, Matsuzaki & Nozaki nom. nov., to encompass Cd. gerloffii, because of presence of the previous valid description of Cr. gerloffii for a different species. The “Cd. subangulosa” strain NIES-2243 was significantly different in morphology from the original description of Cd. subangulosa. It was identified as Cr. typhlos because NIES-2243 and Cr. typhlos strain SAG 26.86 formed a small robust clade with essentially the same morphological characteristics except for the presence or absence of an eyespot in the chloroplast.
