Stentor introversus Tartar, 1958

Kim, Ji Hye, Omar, Atef & Jung, Ji Hye Moon and Jae-Ho, 2020, Taxonomy of 16 indigenous ciliate species (Protozoa, Ciliophora) from South Korea, Journal of Species Research 9 (4), pp. 427-442 : 428

1. Stentor introversus Tartar, 1958 ( Fig. 1 )

Material examined. Brackish water with debris (salinity, 7.6‰) collected from Songji Lake , Oho-ri , Jugwangmyeon , Goseong-gun, Gangwon-do, Korea (38°20′12″N 128°31′4″E) on 17 May 2019 .

Diagnosis. Extended body size in vivo 500-600 × 200- 250 μm and trumpet-shaped, contracted body size 250- 305 × 200-250 μm in vivo (n = 10) and pouch-shaped with retracted buccal field; cytoplasm colorless; 2 kinds of cortical granules densely arranged in between somatic kineties, larger granules turquoise and 0.4-0.5 μm in diameter, smaller granules reddish and 0.2-0.3 μm in diameter; 250 adoral membranelles; 60-73 somatic kineties; 16-20 buccal kineties including 1 peristomial kinety; moniliform macronucleus with 9-14 nodules.

Distribution. U.S.A. and Korea.

Remarks. Stentor introversus was not reported since the original description by Tartar (1958) from USA. It differs from the most similar species, S. coeruleus (Pallas, 1766) Ehrenberg, 1831 , in the extended body size (500-600 μm vs. 1-2 mm), buccal field retracted when contracted (present vs. absent), and the number of types of cortical granules (2 vs. 1) ( Foissner et al., 1992; Foissner and Wölfl, 1994).

Voucher slides. Two slides with protargol-impregnated specimens were deposited at National Institute of Biological Resources (NIBRPR0000110205, NIBRPR0000110 206).

Figures

Fig. 1. Photomicrograph of Stentor introversus in vivo (A-C) and after protargol impregnation (D). A. Extended body. B. Contracted body. C. Two kinds of cortical granules (smaller reddish and larger turquoish). D. Buccal field. CG, cortical granules; MA, macronuclear nodule. Scale bars=50μm (A, D); 200 μm (B); 20μm (C).