Dysteria crassipes Claparède & Lachmann, 1859

Wang, Congcong, Qu, Zhishuai & Hu, Xiaozhong, 2019, Morphology and SSU rDNA sequences of four cyrtophorian ciliates from China, with description of a new species (Protista, Ciliophora, Phyllopharyngea), Zootaxa 4664 (2), pp. 206-220 : 213-214

Dysteria crassipes Claparède & Lachmann, 1859

( Fig. 5 F–I; Table 2 )

Morphological description. Cell size about 50 – 60 × 35 – 45 μm in vivo. Body shape oval in side view, with anterior end rounded and posterior end slightly narrowed ( Fig. 5F ). Two nematodesmal rods, each about 25 μm long. Two contractile vacuoles, about 5 μm across, ventrally positioned at about anterior and posterior third of cell, respec- tively; each pulses at an interval of 1–2 min ( Fig. 5F ). Dorsal spine absent. Many bar-shaped ectosymbiotic bacteria often detected on cell surface ( Fig. 5G ). Macronucleus about 25 × 15 μm in vivo. Micronucleus not detected. Mainly feeds on diatoms and bacteria.

Invariably four right kineties with loosely arranged basal bodies including two frontoventral kineties with 89–121 basal bodies each. Six to eight left kineties ( Fig. 5H ). Two circumoral kineties, one preoral kinety, and three left frontal kineties located in oral area ( Fig. 5I ). Terminal fragment composed of six or seven kinetosomes ( Fig. 5I ). Equatorial fragment consists of 4–20 basal bodies.

SSU rRNA gene sequence and phylogenetic position. The GenBank accession number, length, and G + C content, are MK 882889 , 1,571 bp, and 45.39%, respectively. The closest related Dysteria form is Dysteria crassipes ( KC 753492 ) with a 99.7% sequence similarity. The sequence similarity of Dysteria crassipes ( MK 882889 ) to D. crassipes ( FJ 868206 ) is 99.5%. Phylogenetic trees ( Fig. 6 ) show our isolate forms a clade with three other forms of C. crassipes with solid support values.

Figures

FIGURE 5. Photomicrographs of Dysteria monostyla (A–E) and D. crassipes (F–I) from live (A, B, F, and G) and after protargol impregnation (C–E and H, I). A. Left lateral view of a representative individual, arrowheads show contractile vacuoles (CV). B. Cell surface, arrow refers to the transverse stripe, arrowhead shows bar-shaped ectosymbiotic bacteria. C. Left lateral view of ciliary pattern. D. Anterior part of cell. E. Ventral view of mid-body. F. Left lateral view of a representative individual, arrows point to contractile vacuoles. G. Rod-shaped ectosymbiotic bacteria attached on cell surface (arrowheads). H, I. Left lateral views of ciliature.Abbreviations: Co—circumoral kineties; EF—equatorial fragment; FvK—frontoventral kineties; Lfleft frontal kineties; LK—left kineties; Ma—macronucleus; Pr—preoral kinety; RK—right kineties; TF—terminal fragment. Scale bars: 30 μm (A, C, F and H).

FIGURE 6. Phylogenetic tree of Maximum-likelihood (ML) based on small SSU rRNA gene sequences with Bayesian inference (BI) tapped on it. The four new sequences in the present paper are highlighted in bold. Numbers at nodes show ML bootstrap values and the BI posterior probabilities (ML/BI). Values with full support (ML/BI, 100/1.00) are marked with solid circle. The scale bar corresponds to 5 substitutions per 100 nucleotide positions. * Guangdong population of Chlamydodon bourlandi, ** misidentification, should be Chlamydodon bourlandi.