Brachonella contorta ( Levander, 1894 )

Jung, Atef Omar and Jae-Ho, 2022, New record of five anaerobic ciliate species from South Korea, Journal of Species Research 11 (2), pp. 108-116 : 109-110

1. Brachonella contorta ( Levander, 1894)

Jankowski, 1964 ( Fig. 1 )

Material examined. Freshwater sample collected from Bunhwangji, Nakdong-myeon, Sangju-si, Gyeongsang-

buk-do, Republic of Korea (36°23′50.4″N, 128°15′47.7″E) on 26 April 2021 .

Diagnosis. Size 80-100 × 40-60 μm in vivo and 60-80 × 35-50 μm after protargol impregnation (n = 7); body bullet-shaped, preoral dome very large, conical, postoral part short and bluntly truncate; cortex covered with minute cortical granules arranged in rows between somatic kineties; cytoplasmic granules yellowish to brownish, aggregate at anterior end of ventral side of preoral dome; cytostome displaced in posterior end of body at end of adoral zone; one globular macronucleus and one micronucleus in anterior half of body; 40-50 dikinetidal ciliary rows, 20 of which are dome kineties, caudal cilia slightly elongated; perizonal ciliary stripe consists of 5 rows, rows 1-3 close together and separated from rows 4 and 5, rows 1-3 not arranged in false kineties; adoral zone makes 360° spiral around long axis, comprises ~60 polykinetids on average. World distribution. Cosmopolitan ( Levander, 1894; Kahl, 1932; Schulze, 1959; Jankowski, 1964a; Dragesco and Dragesco-Kernéis, 1986; Bourland et al., 2017a).

Remarks. The Korean population of Brachonella contorta agrees to the most recent description of Bourland et al. (2017a) from USA in almost all features. Brachonella contorta also agrees with other descriptions, however, the species shows high morphological variability ( Levander, 1894; Kahl, 1932; Schulze, 1959; Jankowski, 1964a; Dragesco and Dragesco-Kernéis, 1986; Bourland et al., 2017a). According to Bourland et al. (2022), six species are included to the genus Brachonella so far: B. comma Bourland et al., 2022 ; B. contorta ( Levander, 1894) Jankowski, 1964a ; B. cydonia ( Kahl, 1927) Jankowski, 1964b ; B. lemani (Dragesco, 1960) Jankowski, 1964a ; B. elongata Jankowski, 1964b ; and B. pulchra ( Kahl, 1927) Bourland et al., 2018a . However, only B. comma , B. contorta , and B. pulchra are morphologically well characterized. Brachonella contorta could be easily separated from B. comma by the bullet-shaped (vs. elongate) body shape, the straight (vs. ventrally curved) body axis, and the number of somatic kineties (>34 vs. 20-25). Also, it could be easily separated from B. pulchra by the shape of the preoral dome (conical vs. broadly rounded). Furthermore, it is the only species within the genus Brachonella with a prominent anterior apical suture, the cytostome in posterior end of body, and it has the higher degree (360°) of adoral zone spiralization ( Jankowski, 1964a; 1964b; Bourland et al., 2017a; 2018a; 2022).

Voucher slide. One slide with protargol-impregnated specimens was deposited at the National Institute of Biological Resources (NIBRPR0000111066).

Figures

Fig. 1. Brachonella contorta in life (A) and after protargol impregnation (B, C). A. Ventral view showing the body shape, the adoral zone of polykinetids, which extends to posterior body end and spirals 360° around long body axis, and the long preoral dome. B, C. Ventral and dorsal view showing the somatic and oral ciliature, the perizonal ciliary stripe, and the nuclear apparatus.AZP, adoral zone of polykinetids; MA, macronucleus; MI, micronucleus; PS. Perizonal ciliary stripe. Scale bars 20μm.