Description of Chloromonas kasaiae sp. nov. (Volvocales, Chlorophyceae), based on comparative electron microscopy and molecular data

Chloromonas kasaiae sp. nov. (Volvocales, Chlorophyceae) was described based on a new culture strain originating from Japan. Based on light microscopy, vegetative cells of this new species were very similar to those of C. reticulata and C. serbinowii. However, C. kasaiae differed from these two species in the ultrastructure of eyespots (number of globule layers). Our phylogenetic analyses, based on a combined data set from nuclear-encoded 18S ribosomal (r) RNA, the ATP synthase beta subunit and P700 chlorophyll a apoprotein A2 genes, robustly resolved that C. kasaiae was separate from C. reticulata. Although these analyses did not resolve the phylogenetic relationship between C. kasaiae and C. serbinowii, separation of the two was supported based on a comparison of the secondary structure of nuclear rDNA internal transcribed spacer 2.