We discovered a new marine cyrtophorid ciliate, Dysteria nabia nov. spec., in Incheon Harbor in the Yellow Sea and at Ihoteu Beach on Jeju-do Island, South Korea. This new species is described based on live observations, protargol impregnation, and silver nitrate impregnation. Dysteria nabiameasures approximately 94 × 45 µm in vivo and has an oval to elliptical form, with a subcaudally positioned podite; 5 right kineties, with a single shortened innermost right kinety; usually 3 left frontal kineties; and 2 contractile vacuoles. The length of the small subunit ribosomal RNA (SSU rRNA) gene sequence is 1,700 bp. In comparison with the five previously identified sequences ofDysteria species, the inter-specific similarity of D. nabia ranges from 91.5 to 98.4%.
