Parauronema cf. longum Song, 1995

Fig. 3 E–J; Table 1

Description

Description based on Alabama population: body 60–85 × 25–35 µm in vivo, elongate oval with a large, truncated apical plate (Fig. 3 E–G). Body shape generally constant. Posterior end rounded, ventral side straight, dorsal side convex (Fig. 2 E–F). Buccal field 35–40% of body length. Pellicle slightly indented at bases of cilia. Extrusomes rod-shaped, ca 2–3 µm long. Cytoplasm colourless to grayish, containing several to many large (ca 5 μm across) food vacuoles and dumbbell-shaped crystals (ca 1–2 µm long) concentrated in anterior and posterior ends of body (Fig. 3 H). Single ellipsoid to spherical macronucleus, 10 µm in diameter, micronucleus not identified. Single contractile vacuole, 8 μm across during diastole, at posterior end of cell. Somatic cilia 6 μm- long, densely arranged (Fig. 3 F, arrows); single caudal cilium approximately 15 μm long (Fig. 3 I). Swims straight ahead in slightly helical path. Crawls slowly with frequent changes of direction when feeding on surface of debris or stays quiet for long period. Eighteen to 24 somatic kineties, somatic kinety 1 with about 32 basal bodies. Somatic cilia about 5 to 7 µm long. M1 long, consisting of two longitudinal rows of kinetids, each with seven to ten kinetosomes (Fig. 3 J). M2 well-separated from M1, composed of three rows of kinetosomes, each row containing six kinetosomes (Fig. 3 J). M3 much shorter than M1 and M2, comprising two or three short, irregularly arranged rows of kinetosomes (Fig. 3 J). PM on right of buccal cavity, terminating anteriorly at level of mid-region of M2. Scutica Y-shaped comprising four pairs of kinetosomes (Fig. 3 J).

* Basal body pairs counted as single ones

Five free-living scuticociliates