Description of a New Brackish Water Ciliate, Uronychia xinjiangensis n. sp. (Ciliophora, Euplotida) Based on Morphology, Morphogenesis and Molecular Phylogeny

A brackish water euplotid ciliate, Uronychia xinjiangensis n. sp., was discovered in a ditch in Yuli County, Xinjiang, China. Its morphology, ciliature and morphogenesis were investigated based on specimens examined in vivo and following protargol staining. The new species is characterized by the posterior part of the adoral zone composed of three membranelles, which has never been seen in all other known congeners. Other morphologic features include: (i) body oval-shaped, with conspicuous right anterior spur-like protrusion; (ii)size in vivo 60-90 × 40-68 μm; (iii) two macronuclear nodules; (iv) four frontal, two ventral, five transverse, three left marginal and three caudal cirri. Its morphogenesis proceeds in a usual way, except that the oral primordium forms only three proximal membranelles rather than four proximal membranelles within congeners. The small subunit rRNA gene of the new species (GenBank accession number: KX147287) comprises 1723 bp and 44.63% GC content, and differs by 0.12-1.81% from those of congeners. Phylogenetic analyses based on SSU rRNA gene sequence data reveal that Uronychia xinjiangensis n. sp. clusters with other Uronychia species with full support, which supports the monophyly of the genus Uronychia Stein, 1859.