Uronema marinum Dujardin, 1841

Fig. 4 F–I; Table 1

Description

Description based on Alabama population: Size in vivo 10–25 × 6–10 μm, elongate-elliptical in outline (Fig. 4 F). Anterior end flat, with an apical plate, dorsal posterior area slightly rounded (Fig. 4 F–H). Buccal field 50% of body length. Pellicle smooth (Fig. 4 F–I). Extrusomes approximately 1 µm long, rodshaped, closely beneath pellicle. One large globular to ellipsoidal macronucleus centrally located with numerous tiny (approximately 1×1 μm) irregularly-shaped peripheral nucleoli (Fig. 4 F–I). Contractile vacuole about 3 μm in diameter at posterior end of cell (Fig. 4 H). Movement unremarkable, either swimming continuously or resting on the bottom. Twelve to 13 ciliary rows. Buccal apparatus typical of genus: M1 positioned near apical plate and composed of 5–7 kinetosomes; M2 slightly longer than M1; M3 very short (Fig. 4 I). PM on right of shallow buccal cavity, composed zigzaging row of basal bodies, extending anteriorly to middle of M2 (Fig. 3 I).