Mikhail Tribun

Zoological Institute RAS, 199034 St. Petersburg, Russia

| Submitted June 13, 2022 | Accepted November 17, 2022 |

Summary

Euplotes japonicum sp. n. is a new species of Euplotes described from the Peter the Great Gulf, Sea of Japan. Traditional morphological (silver nitrate staining, Feulgen staining, DIC) and molecular (sequencing the SSU rRNA gene) methods were used in the study. E. japonicum characteristics: body size about 94×47 µm, a single-vannus dargyrome, 8–9 dorsolateral kineties with 17–21 cilia in central row, 10 frontoventral cirri, 5 transverse cirri, 3–5 caudal cirri, wide and deep peristome with 41–52 adoral membranelles. The best 100 hits in BLASTn analysis belong to the genus Euplotes, with E. crassus (Dujardin, 1841) Kahl, 1932 – 99.73%, and E. vannus (Muller, 1786) Minkjewicz, 1901 – 99.68%.

Key words:  ciliates, Euplotes, morphological characteristics, phylogenetic analysis, SSU rRNA gene, the Sea of Japan