Parauronema cf. longum Song, 1995

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 : 4-6

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).

Five free-living scuticociliates

Figures

Fig. 2. A – D. Mesanophrys cf. carcini Small & Lynn in Aescht, 2001. E – G. Metanophrys similis Song et al., 2002. A – C, E – F. In vivo. D, G. After silver impregnation. A, E. Ventral views of typical individuals, arrow in (E) shows caudal cilia. B, F. Different individuals, showing different body shapes. C. Individual in morphogenesis. D, G. Detailed structure of the buccal area. Abbreviations: M 1, 2, 3 = membranelle 1, 2 and 3; Ma = macronucleus; PM = paroral membrane. Scale bars: 30 μm.

Fig. 3. A – D. Pseudocohnilembus hargisi Evans & Thompson, 1964. E – J. Parauronema cf. longum Song, 1995. A – C, E – I. In vivo. D, J. After silver impregnation. A, E. Ventral views of typical individuals, arrow in (A) shows caudal cilia. B – C, F – G. Different individuals, showing varying body shapes, arrowheads in (F) mark somatic kineties. D, J. Detailed structure of the buccal area. H. Ventral view, arrow refers to dumbbell-shaped crystals. I. Posterior end, arrow marks caudal cilium. Abbreviations: M 1, 2, 3 = membranelle 1, 2 and 3; PM = paroral membrane; Sc = scutica. Scale bars: A – B = 15 μm; C, E = 40 μm; G = 60 μm.

Tables

Table 1. Morphometric characterization of seven species from Alabama populations. Data based on silver carbonate-impregnated specimens. Measurements in µm. Abbreviations: CV = coefficient of variation in %; n = number of specimens investigated; Max = maximum; Mean = arithmetic mean; Min = minimum; SD = standard deviation.

Character Species	Min	Max	Mean	SD	CV	n
Body length Mesanophrys cf. carcini	43	74	61.2	11.9	16.3	15
Uronema marinum	21	32	27.8	9.6	5.2	15
Metanophrys similis	48	56	51.2	5.8	6.7	15
Uronemita filificum	40	46	43.8	3.7	5.6	15
Pleuronema setigerum	72	80	76.0	7.3	8.0	15
Pseudocohnilembus hargisi	43	57	49.1	6.7	8.9	15
Parauronema cf. longum	86	92	89.1	9.3	7.5	15
Body width Mesanophrys cf. carcini	20	31	23.2	16.4	10.2	15
Uronema marinum	12	18	15.4	7.2	3.7	15
Metanophrys similis	31	38	33.5	10.9	7.1	15
Uronemita filificum	27	30	28.1	7.9	2.1	15
Pleuronema setigerum	35	45	41.3	6.5	7.2	15
Pseudocohnilembus hargisi	11	16	14.4	3.3	5.6	15
Parauronema cf. longum	38	47	44.7	7.1	4.3	15
Number of somatic kineties Mesanophrys cf. carcini	10	10	10.0	0	0	13
Uronema marinum	12	13	12.3	5.2	4.7	14
Metanophrys similis	12	12	12.0	0	0	15
Uronemita filificum	23	24	23.2	2.9	2.8	13
Pleuronema setigerum	13	14	13.7	8.5	3.4	12
Pseudocohnilembus hargisi	6	7	6.4	6.7	7.1	14
Parauronema cf. longum	18	21	20.1	2.4	5.6	13
Macronucleus length Mesanophrys cf. carcini	8	13	10.7	19.3	16.5	15
Uronema marinum	8	10	9.2	12.5	14.7	15
Metanophrys similis	12	15	13.2	3.2	1.3	15
Uronemita filificum	15	17	15.9	7.2	3.9	15
Pleuronema setigerum	15	18	16.6	4.5	7.6	15
Pseudocohnilembus hargisi	6	8	7.3	6.1	2.6	15
Parauronema cf. longum	15	18	16.2	4.3	4.6	15
Macronucleus width Mesanophrys cf. carcini	8	12	11.1	14.7	11.7	15
Uronema marinum	10	11	10.7	5.1	2.5	15
Metanophrys similis	14	15.3	4.3	5.7	15	16
Uronemita filificum	16	18	17.8	4.1	3.6	15
Pleuronema setigerum	15	17	15.7	7.8	6.7	15
Pseudocohnilembus hargisi	6	7	6.4	11.3	13.4	15
Parauronema cf. longum	14	17	15.9	5.0	4.1	15
Kinetosomes in kinety 1, number* Mesanophrys cf. carcini	27	31	28.8	5.7	2.0	15
Uronema marinum	17	22	20.2	2.4	1.2	15
Metanophrys similis	24	26	25.2	9.8	3.9	15
Uronemita filificum	18	24	22.4	6.4	2.8	15
Pleuronema setigerum	-	-	-	-	-	15
Pseudocohnilembus hargisi	16	19	18.4	10.1	5.6	15
Parauronema cf. longum	22	25	23.4	1.2	0.5	15

* Basal body pairs counted as single ones