• Animal Systematics, Evolution and Diversity
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• v.40 no.4
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• pp.323-331
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• 2024

This study focuses on the diversity of ciliates inhabiting the oxygen-depleted conditions in freshwater ponds in Korea. We identified two species, Bothrostoma nasutum (Cunha, 1915) Jankowski, 1964 and B. undulans Stokes, 1887, for the first time in Korea. Their morphological characteristics were determined based on observations of both live and protargol-impregnated specimens. Bothrostoma nasutum is characterized by body size 70-85×25-35 ㎛ in vivo, body shape elongated ellipsoidal, anterior end extended as a proboscis; total 22-29 somatic kineties (including 7-8 postoral kineties), cortical granules arranged in 5 or 6 short, oblique rows; and 19-23 adoral membranelles. While B. undulans has the following features: body size 70-120×20-45 ㎛ in vivo, body shape elongated ellipsoidal, anterior end terminated by an acute snout; total 18-22 somatic kineties (including 5-7 postoral kineties); 17-22 adoral membranelles; and cortical granules obliquely arranged in 6 or 7 short rows. Recently, the increasing interest in research on anaerobic ciliates has contributed to the understanding of the diversity of ciliates in Korea.