Tetrahymena rostrata ( Kahl, 1926 ) Corliss, 1952

Jung, Atef Omar and Jae-Ho, 2021, New record of 21 ciliate species (Protozoa, Ciliophora) from South Korea, Journal of Species Research 10 (3), pp. 301-320 : 314-315

18. Tetrahymena rostrata ( Kahl, 1926) Corliss, 1952

( Fig. 17 )

Material examined. Freshwater sample collected from a temporary puddle, after a rainfall, on a footpath behind

Gangneung-Wonju National University , Gangneung, Korea (37°46 ʹ 30 ʺ N, 128°51 ʹ 46.8 ʺ E) on 25 June 2020 .

Diagnosis. Length in vivo 35-50 × 20-25 μm; body has two shapes, slenderly ellipsoid theronts and broadly ellipsoid trophonts; pellicle indented at base of cilia; cytoplasm colorless filled with food vacuoles contain bacte- ria; 1 or 2 macronuclear nodules with 1 micronucleus at mid-body; invariably 25 somatic ciliary rows including 2 postoral rows; oral apparatus consists of semicircular dikinetidal paroral right of oral opening and 3 membranelles on left wall of buccal cavity; a single subterminal contractile vacuole with 2 excretory pores; a single caudal cilium.

Distribution. Cosmopolitan.

Remarks. The Korean population of T. rostrata agrees with other populations in the body size, shape and habitat but differs mainly in the smaller body size and the lower number of somatic ciliary rows (invariably 25 vs. 26-31 from Foissner (1987; 2016) and 29-44 from Segade et al. (2009)). This species is also very similar to T. setosa (Schewiakoff, 1893) McCoy, 1975 in the overall shape and size but differs significantly in the formation of rest- ing cysts (present vs. absent) ( Kahl, 1926; 1931; Corliss, 1952; 1973; Foissner, 1987; 2016; Segade et al., 2009; 2015).

Voucher slides. Two slides with protargol-impregnated specimens were deposited at the Nakdonggang National Institute of Biological Resources (NNIBRPR20133, NNIBRPR20134).

Figures

Fig. 17. Photomicrographs of Tetrahymena rostrata from life (A, B) and after silver carbonate impregnation (C, D). A, B. Ventral views showing the body shape and the location of the oral apparatus. C, D. Dorsal (C) and ventral (D) view showing the somatic ciliature, the nuclear apparatus, the oral membranelles (arrowheads), and the paroral (arrow). CC, caudal cilium; MA, macronucleus; MI, micronucleus; OA, oral apparatus. Scale bars=20μm.