Two new scuticociliates from southern China: Uronema apomarinum sp. nov. and Homalogastra parasetosa sp. nov., with improved diagnoses of the genus Homalogastra and its type species Homalogastra setosa (Ciliophora, Oligohymenophorea)

The morphology of two new scuticociliates, Uronema apomarinum sp. nov. and Homalogastra parasetosa sp. nov., isolated from a mangrove wetland in Shenzhen, PR China, was studied using live observation and the protargol impregnation method. Uronema apomarinum is characterized by a body size of about 20–35×10–15 µm in vivo, a partly two-rowed membranelle 1, and 12 or 13 somatic kineties. Homalogastra parasetosa is distinguished by a membranelle 1 comprising two longitudinal rows of basal bodies. Three Homalogastra setosa populations are suggested as subjective synonyms of the new species. Improved diagnoses of the genus Homalogastra Kahl, 1926 and its type species Homalogastra setosa Kahl, 1926 are provided. Results of phylogenetic analyses based on 18S rRNA gene and ITS1-5.8S–ITS2 region sequences indicate that U. apomarinum is most closely related to U. marinum, while the closest relative of H. parasetosa is H. setosa.