Cyrtohymena muscorum ( Kahl, 1932 ) Foissner,

Kim, Yeon Uk, Lee, Jung Mi, Kwon, Choon Bong & Shin, Mann Kyoon, 2012, Morphological redescriptions of three Cyrtohymena ciliates (Ciliophora: Sporadotrichida: Oxytrichidae) new to Korea, Journal of Species Research 1 (1), pp. 78-86 : 82-85

3. Cyrtohymena muscorum ( Kahl, 1932) Foissner,

1989 ḍnjḦỢḄRệ (Ḫḏ) ( Fig. 3 , Table 1)

Steinia muscorum Kahl, 1932, p. 613 , fig. 94a; Foissner,

1982, p. 105-107, figs. 29a-e, table. 24; Berger and Foissner, 1989, p. 41, figs. 79-82, table. 20.

Steinia dubia Gellért, 1956, p. 349 -350, fig. 94a.

Oxytricha muscorum : Borror, 1972, p. 14.

Tachysoma dubia Borror, 1972, p. 15 .

Oxytricha rubra Buitkamp, 1977, p. 122 -123, add. 5.

Oxytricha germanica Foissner, 1987, p. 224 .

Cyrtohymena muscorum : Foissner, 1989, p. 239; Berger, 1999, p. 281 -293, figs. 94, table 20.

General morphology and behavior: Body size in live specimens 160-200 × 50-70 µm, about 180 × 60 µm on average, length: width ratio 3: 1 on average. Body shape long ellipsoid, anterior and posterior ends broadly round- ed, dorsoventrally flattened about 2: 1 ( Fig. 3A ). Body rather flexible. Contractile vacuole located in mid-region of cell near left margin, about 10-15 µm in diameter during diastole, with inconspicuous collecting canals. Cytoplasm colorless and contains some crystals; sized 2-5 µm long, yellowish and drumstick in shape. Cortical granules reddish, 1-1.5 µm across, located mainly in anterior and posterior ends of cell and in groups of two to five around bases of cirri and dorsal bristles; after death granules lose color very rapidly. Locomotion by moderately rapid crawling, sometimes slowly gliding, on bottom of Petri dish.

Buccal field and oral infraciliature: Buccal area long and deep. Adoral zone of membranelles shaped like a question mark, about 30% of cell length, with 44-49 adoral membranelles the widest of which is about 15 µm wide ( Fig. 3A, B ). Undulating membranes in typical Cyrtohymena -pattern; paroral bent in a broad arc along anterior margin of oral cavity; endoral sharply bent in lower third; membranes optically intersect near mid-region of endoral ( Fig. 3B ). Pharyngeal fiber about 25 µm long.

Somatic infraciliature: Three enlarged frontal cirri. Buccal cirrus located right of paroral membrane. Four frontoventral cirri arranged in a V-shape. Three postoral ventral cirri. Two pre-transverse cirri. Five transverse cirri in a J-shaped row, posteriormost cirrus located about level with the posteriormost right marginal cirrus. Right marginal row with 31-34 cirri, left marginal row with 33-36 cirri and extends around posterior end of cell; posterior ends of marginal rows distinctly separated ( Fig. 3B ). Six dorsal kineties ( Fig. 3C ). Three caudal cirri located slightly right of centre ( Fig. 3C ).

Nuclear apparatus: Two ellipsoidal macronuclear nodules 30-43 × 15-28 µm in protargol-stained specimens; both nodules left of cell median; anterior nodule located below buccal vertex, posterior nodule located just below mid-body region ( Fig. 3B ). Three to six ellipsoidal micronuclei close to macronuclear nodules.

Microhabitats. Terrestrial and freshwater.

Distribution. Europe ( Norway, Germany, Austria, Czech Republic and Hungary), Africa ( Cameroon), Asia ( China, Korea and Japan), North America ( U.S.A.) and Antarctica.

Remarks. This species was identified as Cyrtohymena muscorum ( Kahl, 1932) by its flexible body, six dorsal kineties, reddish cortical granules and terrestrial habitat. It does however, differ slightly from the original and subsequent descriptions of populations of C. muscorum from Europe in having a larger body size (210-265 × 70-90 µm vs. 105-155 × 36-56 µm), more adoral membranelles (24- 40 vs. 43-49) and more micronuclei (3-6 vs.2-5) ( Kahl, 1932; Berger and Foissner, 1989). Superficially, C. australis Foissner, 1995 bears the closest resemblance to C. muscorum . However, the former can be separated from the latter by having 2-8 (vs. 3-6) micronuclei, 5-7 (vs. invariably 6) dorsal kineties and yellowish (vs. reddish) cortical granules ( Berger, 1999).

Figures

Fig. 3. Cyrtohymena muscorum (Kahl, 1932) from live (A, D, E, F) and protargol-impregnated specimens (B, C, G). A and D. Ventral view of a typical individual. B and G. Ventral view of general infraciliature. C and E. Dorsal kineties. F. Red cortical granules. Scale bar=50 µm.