Morphology and molecular phylogeny of two colepid species from China, Coleps amphacanthus Ehrenberg, 1833 and Levicoleps biwae jejuensis Chen et al., 2016 (Ciliophora, Prostomatida)

Two colepid ciliates, Coleps amphacanthus Ehrenberg, 1833 and Levicoleps biwae jejuensis Chen et al., 2016, were first recorded in China. Their living morphology, infraciliature and small subunit (SSU) rRNA gene sequences were determined using standard methods. The improved diagnosis of Coleps amphacanthus is as follows:cell size about 100×50 μm in vivo, barrel-shaped; 22-28 ciliary rows each composed of about 14-21 monokinetids and two perioral dikinetids; 5-10 caudal cilia; and one terminal contractile vacuole. Levicoleps biwae jejuensis was also investigated, with an improved diagnosis given based on previous and present work. The phylogenetic analyses based on SSU rRNA gene sequences revealed that all Coleps species were grouped together, except for Coleps amphacanthus, which was grouped into a clade of the genus Levicoleps.