Gonostomum strenuum ( Engelmann, 1862 ) Sterki,

Kim, Kang-San, Park, Kyung-Min, Jung, Jae-Ho & Min, Gi-Sik, 2016, First description of three ciliates (Ciliophora: Stichotrichia) from Korea, Journal of Species Research 5 (3), pp. 468-476 : 473-475

Gonostomum strenuum ( Engelmann, 1862) Sterki,

1878 ( Table 2; Figs. 3 , 4 )

Diagnosis. Cell size in vivo 85 × 25 μm on average, long ellipsoidal shape, slightly flexible ( Figs. 3A , 4A ). Adoral zone 40% of body length ( Table 2; Fig. 4A ). Contractile vacuole at left of mid­body ( Fig. 4C ). Cortical granules present; two elongated macronuclear nodules with two to four micronuclei ( Table 2). Three frontal cirri and one buccal cirrus, two to three cirri in streak III (without frontal cirri), three to four cirri in streak IV, seven to nine cirri in streak V, four to six cirri in streak VI (without pretransverse cirri and transverse cirri), two to four pretransverse cirri, two transverse cirri, and one right and left marginal row ( Table 2; Figs. 2B, 4G ). Three bipolar dorsal kineties, dorsal cilia in vivo 3­4 μm long, with one caudal cirrus each ( Table 2; Figs. 2C, 4F, H ).

Material examined. Heuksan island, Jeollanam­do (34°39′N 125°24′E), collected by Jae­Ho Jung in November , 2011. Gangjeong­dong, Jeju­do province (33°14′ N, 126°30′E), collected by Kang­San Kim in March 2013 .

Deposition. NIBR No. NIBRPR0000107086­ NIBR PR0000107091 with protargol­impregnated specimens have been deposited in the National Institute of Biological Resources, Korea.

Habitat. Moss soil (pH 6).

Distribution. Germany, China, Spain, England, USA, Czechoslovakia, Mexico, Korea.

Remarks. Most characteristics of the Korean population are shared with the Namibian population. The only varying feature is the micronuclei number (3­8 in the Namibian population vs. 2­4 in the Korean population) ( Table 2; Foissner et al., 2002). The higher number of streak cirri and the different termination site of left marginal row (extending to the rear body margin) are distinguishing features of G. strenuum ( Berger, 2011) . In this study, all the Korean data were from the Jeju population.

Gonostomum strenuum can be separated clearly from G. affine , the type species of genus Gonostomum . Gonostomum affine differs from G. strenuum in the following characteristics: number of frontoterminal cirri (2 vs. 3­6); length of frontoventral row (short, row ends ahead of mid­body vs. long, row ends behind of mid­body); number of frontoventral cirri (6­15 vs. 20­25); existence of cortical granules (absent vs. present) ( Table 2) ( Berger, 2011).

Figures

Fig. 3. Morphology of Gonostomum strenuum drawn from life (A) and after protargol impregnation(B, C). A, B, ventral views of representative individuals; C, dorsal view; AZM, adoral zone of membranelles; BC, buccal cirrus; CV, contractile vacuole; DK, dorsal kineties; EM, endoral membrane; FC, frontal cirri; FT, frontoterminal cirri; LMR, left marginal row; Ma, macronuclear nodules; Mi, micronuclei; PM, paroral membrane; PTC, pretransverse cirri; RMR, right marginal row; TC, transverse cirri; CC, caudal cirri. Scale bar: 50μm.

Fig. 4. Photomicrographs of Gonostomum strenuum from life (A­F) and after protargol impregnation (G­I). A, B, G, ventral views; C, D, H, dorsal views, arrows indicate contractile vacuole; E, arrows indicate cortical granules; F, dorsal cilia(arrow) and caudal cirri(arrowhead); I, macronuclear nodules (arrows) and micronuclei (arrowheads); AZM, adoral zone of membranelles, BC, buccal cirrus; DK, dorsal kineties; EM, endoral membrane; FC, frontal cirri; FT, frontoterminal cirri; LMR, left marginal row; Ma, macronuclear nodules; Mi, micronuclei; PM, paroral membrane; PTC, pretransverse cirri; RMR, right marginal row; TC, transverse cirri; CC, caudal cirri. Scale bar: 50μm.