Abstract

Ciliates are unicellular eukaryotes and one of the most abundant and speciose protistan groups. However, their diversity is underestimated, and many new species are waiting for our discovery. During several field surveys conducted from 2018 to 2021 to document indigenous Korean ciliates, 10 unrecorded ciliate species were collected and investigated from freshwater, marine, and semiterrestrial habitats. The morphology of these species was studied based on observation of living and protargol-stained specimens. These species belong to five classes as follows: 1) class Heterotrichea - Peritromus faurei; 2) class Spirotrichea - Heterotachysoma dragescoi, Pseudokeronopsis parasongi, and Certesia quadrinucleata; 3) class Nassophorea - Chilodontopsis depressa; 4) class Prostomatea - Plagiocampa rouxi and Urotricha furcata; and 5) class Oligohymenophorea - Metanophrys similis, Uronema gallicum, and Protocyclidium citrullus. Also, we provide a brief diagnosis, photomicrographs, and information of the locality for each species. Further, we compare each species with the most recent description and with similar congeners.