Metopus, Claparede and Lachmann, 1858

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 : 309-310

11. Metopus es (Müller, 1776) Lauterborn, 1916

( Fig. 11 )

Material examined. Freshwater sample collected from a temporary puddle, after 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 7 April 2020 .

Diagnosis. Size in vivo about 135 × 40 μm (n = 3); body elongate ellipsoidal, slightly sigmoidal, distinctly twist- ed anteriorly and narrowed posteriorly; preoral dome convex with ventral side distinctly convex and studded with brownish granules; 1 ellipsoidal macronucleus and 1 micronucleus in or slightly anterior to mid-body; cortex covered with minute cortical granules in rows between ciliary rows; on average 25 ciliary rows; perizonal stripe consists of 5 rows not arranged in false kineties; adoral zone comprises 36 membranelles on average; caudal cilia longer than somatic cilia.

Distribution. Cosmopolitan.

Remarks. The Korean population of Metopus es agrees with the description of Bourland et al. (2017) in most features. Metopus es is easily confused with other congeners, but it is characterized by a combination of features such as the ciliary rows number, the adoral membranelles number, and the size and position of the nuclear apparatus ( Bourland and Wendell, 2014; Bourland et al., 2017).

Voucher slides. Two slides with protargol-impregnated specimens were deposited at the Nakdonggang National Institute of Biological Resources (NNIBRPR20122, NNIBRPR20123).

Figures

Fig. 11. Photomicrographs of Metopus es from life (A) and after protargol impregnation (B). A. Ventral view showing the torsion of the body and the adoral zone of membranelles. B. Ventral view showing the somatic and oral ciliature, the perizonal ciliary stripe, and the nuclear apparatus. AZP, adoral zone of polykinetids; MA, macronucleus; PM, paroral membrane; PS, perizonal ciliary stripe. Scale bars=20 μm.