Urotricha furcata Schewiakoff, 1892

Omar, Atef & Jung, Ji Hye Choi and Jae-Ho, 2023, New record of ten ciliate species (Protozoa, Ciliophora) from South Korea, Journal of Species Research 12 (1), pp. 95-108 : 102

7. Urotricha furcata Schewiakoff, 1892 ( Fig. 7 )

Material examined. Slightly saline fresh water (salinity 0.4‰) collected from Gyeongpo Stream , Unjeong-dong , Gangneung-si, Gangwon-do, Korea (37°47 ʹ 20.02 ʺ N, 128°54 ʹ 34.47 ʺ E) on April 12, 2018 .

Diagnosis. Size 11 - 16 × 8 - 12 μm after protargol impregnation (n = 5); body broadly ellipsoidal to ovate,

length:width ratio 1.3 - 1.5: 1; macronucleus globular, about 5 μm in diameter, located in body center, micronucleus globular, about 2 μm in diameter, attached to macronucleus; 22 - 23 somatic ciliary rows, each kinety consists of about 12 dikinetids, kineties distinctly shortened posteriorly leaving a barren area with only 2 elongated caudal cilia in center of posterior end, each about half to two thirds of body length; adoral organelles inconspicuous in preparations because very small; oral opening surrounded by oral flaps 1 - 3 μm long each.

Distribution. Austria, Chile, Czech Republic, Ethiopia, France, Germany, Hungary, Iceland, Italy, Norway, Poland, Romania, Slovakia, Spain, Sweden, Switzerland, South Korea.

Remarks. The Korean population of Urotricha furcata agrees with the populations described by Foissner et al. (1994) and Frantal et al. (2022) in most features. The size of U. furcata distinctly shrinks after protargol impregnation and makes the observation of adoral organelles diffi- cult ( Frantal et al., 2022; present study). Members of the genus Urotricha can be distinguished by the number of the caudal cilia. Urotricha furcata belongs to the group with 2 caudal cilia, which contains U. macrostoma and U. pseudofurcata . However, U. furcata can be distinguished from both species in the absence (vs. presence) of extrusomes. Also, U. pseudofurcata is cylindrical while U. furcata is broadly ellipsoidal. Urotricha macrostoma can also be distinguished from U. furcata in the larger body size (30 - 40 vs. 20 - 30 μm in vivo) ( Foissner et al., 1994; 1999; Krainer, 1995; Frantal et al., 2022).

Voucher slides. One slide with protargol-impregnated specimens was deposited at the National Institute of Biological Resources, Korea (NIBRPR0000110844).

Figures

Fig. 7. Urotricha furcata after protargol impregnation. A-C, Ventral (A), posterolateral (B), and dorsal (C) view, showing the body shape, the posteriorly shortened ciliary rows, the non-ciliated posterior area with two caudal cilia, the nuclear apparatus, and the oral flaps sur- rounding the oral opening. AO, adoral organelles; CC, caudal cilia; MA, macronucleus; OF, oral flaps. Scale bars 10 μm.