Morphogenesis of a saline soil ciliate Urosoma salmastra (Dragesco and Dragesco-Kernéis, 1986) Berger, 1999 with notes on the phylogeny of Urosoma (Ciliophora, Hypotrichia)

Morphogenesis in a population of Urosoma salmastra collected from saline soil in Weinan, China, was investigated using protargol staining. The main morphogenetic event that characterizes U. salmastra is the inclusion of cirrus III/2 in the formation of the frontoventra-transverse cirral anlagen. We also provide small subunit ribosomal DNA gene sequences for a population of U. salmastra and for two populations of U. emarginata. The molecular phylogeny indicates that Urosoma is not monophyletic, viz, U. emarginata branches separately from its congeners and the closest relative of U. salmastra is Oxytricha granulifera.