Pleuronema setigerum Calkins, 1902

Xuming Pan, 2016, Seven scuticociliates (Protozoa, Ciliophora) from Alabama, USA, with descriptions of two parasitic species isolated from a freshwater mussel Potamilus purpuratus, European Journal of Taxonomy 249, pp. 1-19 : 9

Pleuronema setigerum Calkins, 1902

Fig. 4 J–N, Table 1

Description

Description of present specimens: Size in vivo 50–70 × 25–35 μm, slender oval in outline, widest at ⅓ posterior end of body ( Fig. 4 J–L). Ventral side almost flat, dorsal side conspicuously convex. Buccal field 80% of body length ( Fig. 4 J–L). Extrusomes 4–5 μm long, closely beneath pellicle. Cytoplasm colourless to grayish containing numerous granules (3–6 µm across) and cytoplasmic crystals of varying size and shape ( Fig. 4 J–L). One spherical macronucleus. Thirteen to 15 elongated caudal cilia about 25 μm in length ( Fig. 4 J–L). Locomotion by swimming while rotating on main body axis, or briefly lying motionless on debris. Twelve to fifteen somatic kineties. Five preoral kineties to left of buccal field ( Fig. 4 M–N). Oral apparatus similar to congeners: M1 with one short and two longer rows; M2a mostly two-rowed but with a middle section that is single-rowed in a ‘zigzag’ pattern, with its posterior end characteristically ring-like. M2b V-shaped, distinctly separated from M2a; M3 three-rowed ( Fig. 4 M– N). PM 80% of body length.

Figures

Fig. 4. A – E. Uronemita filificum Kahl, 1931. F – I. Uronema marinum Dujardin, 1841. J – N. Pleuronema setigerum Calkins, 1902. A – C, F – H, J – L. In vivo. D – E, M – N. After silver impregnation. A, F, J. Ventral views of typical individuals. B – C, G – H, K – L. Different individuals, showing variation in body shape, arrow in (B) shows the conspicuous apical plate, arrows in (C, H) mark contractile vacuoles. D, I, M – N. Detailed structures of buccal area, arrow in (M) indicates the ring-like posterior end of M 2 a, arrowheads in (M) mark preoral kineties. E. Ventral view, arrowheads show somatic kineties. Abbreviations: M 1, 2, 3 = membranelle 1, 2 and 3; M 2 a = the anterior part of membranelle 2; M 2 b = the posterior part of membranelle 2; Ma = macronucleus; PM = paroral membrane. Scale bars: A – B = 20 μm; F, H, N = 10 μm; G = 5 μm, J – L = 30 μm.