Pseudovorticella difficilis (Kahl, 1933) Jankowski

Kim, Ji Hye & Jung, Ji Hye Moon and Jae-Ho, 2018, New records of 24 ciliate species (Protozoa, Ciliophora) collected in South Korea, Journal of Species Research 7 (4), pp. 291-314 : 310

22. Pseudovorticella difficilis (Kahl, 1933) Jankowski ,

1976 ( Fig. 22 )

Material examined. Marine water (salinity 29.6‰) collected from Anin Beach , Gangdong-myeon , Gangneung-si, Gangwon-do, Korea (37°44 ʹ 4.7 ʺ N, 128°59 ʹ 24.2 ʺ E) on May 24, 2018 .

Diagnosis. Zooid size 45-50 × 32-39 μm in vivo; invert-

ed bell-shaped; peristomial lip width about 41-47 μm; annular swellings present on stalk; macronucleus longitudinally oriented J-shape; one contractile vacuole dorsally located; rectangular silverlines about 35 striations between peristomial lip and trochal band, about 18 striations between trochal band and scopula; P1-P3 consisted of 3 rows, shorter inner 1 row of P3, longer and closely spaced outer 2 rows of P3.

Distribution. China, Germany, Korea.

Remarks. The Korean population of P. difficilis is slightly different from the Chinese population in the zooid size (45-50 μm vs. 50-70 μm) ( Ji et al., 2006; Sun et al., 2009). A freshwater P. difficilis var. magnistriata is larger than the marine Korean population (60-140 μm vs. 45-50 μm) and fewer transverse silverlines between peristomial lip and trochal band (25-31 vs. 35) ( Foissner and Schiffmann, 1974; Ji et al., 2006).

Voucher slides. Two slides of protargol-impregnated specimens were deposited at National Institute of Biological Resources, Korea (NIBRPR0000109437, NI- BRPR0000109438) and four slides were deposited at the National Marine Biodiversity Institute of Korea (MABIK PR00043196-PR00043199).

Figures

Fig. 22. Pseudovorticella difficilis in vivo (A, B), after protargol (C, D) and ‘wet’ silver nitrate impregnation (E). A. Typical individuals and annular swelling (arrow) on stalk. B. Contractile vacuole (arrowhead) and annular swelling (arrow) on stalk. C. Infundibular polykinety 1-3 (arrowhead indicates longer and closely spaced outer two rows). D. Epistomial membrane (arrowhead) and macronucleus (arrow). E. Rectangular silverlines(arrow indicates trochal band). Scale bars=100 μm (A), 50 μm(B).