Eurystomatella sinica Miao et al., 2010

Jung, Jae-Ho, 2021, Taxonomy of four scuticociliates (Protozoa: Ciliophora) from coastal waters of South Korea, Journal of Species Research 10 (2), pp. 184-190 : 185-186

1. Eurystomatella sinica Miao et al., 2010 ( Fig. 1 )

Material examined. Coastal water sample (25.4‰, 21.0℃) collected from Yeosu-si, Jeollanam-do, Republic of Korea (34°2′50″N, 127°17′33″E) on 10 July 2019 .

Diagnosis (n = 12). Cell size 42.5-51.7 × 16.5-20.1 μm

(47.8 × 18.5 μm on average) in protargol preparations, outline elongated oval with slightly concave right margin, dorsoventrally flattened; 1 elliptical macronucleus in midbody, 7.9-10.8 × 6.5-9.0 μm (9.9 × 7.9 μm on average) in size; micronucleus not observed; invariably 15 somatic kineties, prolonged caudal cilia; buccal area occupying 69.4-78.8% (72.6% on average) of body length; paroral membrane conspicuous, forms an elliptical ring with anterior opening closed by membranelles 1-3; membranelle 1 (M1) 2-rowed; right membranelle 2 (M2a) about 7-9-rowed; left membranelle 2 (M2b) 3-5-rowed; membranelle 3 (M3) 2- or 3-rowed (it should be noted that these ciliary rows on the membranelles 2 and 3 are arranged too closely, that is the numbers are approximate).

Distribution. China ( Miao et al., 2010) and Korea (this study).

Remarks. The genus Eurystomatella is monotypic (type species: E. sinica by original designation) ( Miao et al., 2010). The Korean population corresponds very well with the type population, but the former shows slightly smaller body size (on average, 47.8 × 18.5 μm vs. 57.5 × 34.1 μm in protargol preparations) ( Miao et al., 2010). The difference may be due to the impregnation method or habitat condition ( Foissner, 2014).

Voucher slides. Three slides with protargol-impregnated specimens were deposited at the National Marine Biodiversity Institute of Korea (GUC002230-2232).

Figures

Fig. 1. Eurystomatella sinica after protargol impregnation. A, C. Ventral views showing infraciliature and macronucleus. B. Dorsal view showing somatic kineties. Ma, macronucleus; M1, M2a, M2b, M3, oral membranelles; PM, paroral membrane; SK, somatic kineties. Scale bar=30 μm.