11. Urocentrum turbo (Müller, 1786) Nitzsch, 1827

(Fig. 11)

Material examined. Freshwater taken from the Gasiyeonseupji wetland, Unjeong-dong, Gangneung-si, Gangwon-do, Korea (N37°47 ʹ 15 ʺ, E128°53 ʹ 42 ʺ) on October 7, 2016 .

Diagnosis. Body size about 60-70 × 45-50 μm in vivo; cork or dumbbell shaped; anterior half wider than posterior body with slightly narrowed mid-body; contractile vacuole terminally located; numerous spindle shaped extrusomes; frontal ciliary band composed of 17-26 rows of kinetids; equatorial ciliary band composed of 80-140 kineties; somatic kineties irregular arranged; 3 buccal membranes; tail cirrus conspicuous; macronucleus, horizontal C-shape in posterior half of body, a single spherical micronucleus attached near macronucleus.

Distribution. Cosmopolitan including Korea (this study).

Remarks. Urocentrum (Müller, 1786) is a monotypic genus. The body shape and somatic ciliature are unique and easy to recognize in this species at low magnification. Urocentrum turbo predominantly inhabits eutrophic waters (Foissner et al., 1994).

Voucher slides. Two slides, including protargol-impregnated specimens, were deposited at the National Institute of Biological Resources, Korea (NIBRPR0000107914, NIBRPR0000107915).