On four epibiotic peritrichous ciliates (Protozoa, Ciliophora) found in Lake Weishan Wetland: morphological and molecular data support the establishment of a new genus, Parapiosoma gen. nov., and two new species

Abstract

AbstractDuring a study on the diversity of ciliated protists in Lake Weishan Wetland, the largest wetland in northern China, four epibiotic sessilid peritrichs were isolated from aquatic host animals. Two of them, i.e.,Epistylis cambariKellicott, 1885 andEpistylis lwoffiFauré-Fremiet, 1943, were known species whereas the other two, i.e.,Parapiosoma typicumgen. nov., sp. nov. andOrborhabdostyla gracilissp. nov., are new to science. The new genusParapiosomagen. nov. is characterized by its branched non-contractile stalk, everted peristomial lip, obconical macronucleus and transverse silverlines. Two species are assigned to the new genus, namelyParapiosoma typicumsp. nov. andParapiosoma gasterostei(Fauré-Fremiet, 1905) comb. nov. Morphologically,P. typicumsp. nov. is recognized by its goblet-shaped zooids, single-layered peristomial lip, dichotomously branched stalk, and infundibular polykinety 3 (P3) containing three equal-length rows.Orborhabdostyla gracilissp. nov. is characterized by its slender zooid, curved macronucleus, and three equal-length rows in infundibular P3. Improved diagnoses and redescriptions ofE. cambariandE. lwoffiare provided including, for the first time, data on the ciliature ofE. cambari. Phylogenetic analyses based on SSU rDNA, ITS1-5.8S rDNA -ITS2, and LSU rDNA sequence data strongly support the assertion that the family Epistylididae comprises morphospecies with different evolutionary lineages and indicate thatParapiosomagen. nov. may represent a new taxon at family level.