Sterkiella tetracirrata Kumar 2015
Creators: name: Min, Kyu-Seok Chae and Gi-Sik
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Hypotrichea
Oxytrichida
Oxytrichidae
Sterkiella
Sterkiella tetracirrata

description: 3. Sterkiella tetracirrata Kumar et al., 2015 (Table 1,   Figs. 6 and 7)  
 Sterkiella tetracirrata Kumar et al., 2015: p. 86.   
Korean name. IJūAEŀljǿAEệ  
 Material examined. Soil, Cheonan-si, Chungcheongnam-do, South Korea (36°54 ʹ 03.9 ʺ N 127°12 ʹ 21.1 ʺ E, 1), collected by Kyu-Seok Chae in June 2019.   
 Diagnosis of the Korean population. Size in vivo about 110 × 55 μm, ellipsoidal body shape; 4 macronuclear nodules; contractile vacuole at left of mid-body; 25-40 adoral membranelles; cortical granules absent; 3 frontal cirri; 4 frontoventral cirri; 3 postoral ventral cirri; 2 pretransverse cirri; 4 transverse cirri; one buccal cirrus; one left and one right marginal cirral row; 3 caudal cirri; 4 dorsal and 2 dorsomarginal kineties.   
 Description. Body size in vivo 100-120 × 50-60 μm, 85-122 × 40-67 μm after protargol impregnation (Table 1). Body shape elongated elliptical with rigid cortex (Figs. 6A, 7C, 7E, 7F). Length to width ratio about 2:1. Contractile vacuole on left side of mid-body, about 14 μm in diameter (Figs. 6A, 7B, arrow). Four macronuclear nodules and three to six micronuclei (Figs. 6C, 7D). Cortical granules absent. Cytoplasm colorless.   
Adoral zone membranelles conspicuous, about 32% of the body length, comprising 25-40 membranelles (Fig. 6B, Table 1). Both paroral and endoral membranes curved leftward anteriorly (Fig. 6B). Three frontal, one buccal, three postoral-ventral cirri, two pretransverse and four transverse cirri (Figs. 6B, 7E, Table 1). One right (24-30 cirri) and left (21-30 cirri) marginal row (Figs. 6B, 7E, Table 1). Dorsal ciliature composed of four kineties and two dorsomarginal rows, three caudal cirri located at ends of dorsal kineties 1, 2, 4 on posterior end (Figs. 6C, 7F, Table 1).  
 Distribution. India and South Korea (This study).   
 Remarks. Sterkiella tetracirrata differs from S. cavicola (Kahl, 1935) Foissner et al., 1991 by the number of transverse cirri (4 vs. 5) (Foissner et al., 1991). Sterkiella tetracirrata can be distinguished from S. quadrinucleatus (Sick, 1933) Berger, 1999 by the number of transverse cirri (4 vs. 6-8) and habitat (soil vs. marine or brackish) (Berger, 1999). Sterkiella tetracirrata differs from S. terricola Berger, 1999 in the number of adoral membranelles (25-40 vs. 22-23), transverse cirri (4 vs. 3), and right and left marginal cirri (about 26 and 24 vs about 20 and 17) (Berger, 1999).   
 The morphology of the Korean population corresponds to the type population from India, but they are slightly different in the number of right and left marginal cirri (24-30 and 21-30 vs 21-25 and 20-23) (Kumar et al., 2015).   
 The 18S rDNA gene sequence of S. tetracirrata was 1770 bp in length (GenBank accession number: OM 212986). The Korean and Indian populations formed a highly supported clade (99% ML, 0.94 BI) in the phylogenetic tree (double-arrowhead in Fig. 8). The Korean and the Indian populations were identical, and had a sequence divergence of 0.12% to its congener S. multicirrata (2 nt difference).   
 Deposition. The voucher slide with protargol-impregnated specimens is deposited in the National Institute of Biological Resources in Korea (NIBRPR0000110852).
description: Published as part of Min, Kyu-Seok Chae and Gi-Sik, 2022, New record of three oxytrichid ciliates (Ciliophora: Oxytrichidae) from South Korea, pp. 287-295 in Journal of Species Research 11 (4) on pages 293-294, DOI: 10.12651/JSR.2022.11.4.287, http://zenodo.org/record/13138793