Ciliates from the faeces of the free-ranging dromedary from Oman: Morphology and molecular phylogeny.

Ciliates Infundibulorium cameli from the faeces of the free-ranging dromedary from Oman were studied using a set of methods of the light and immunofluorescence microscopy and molecular phylogeny. With the use of molecular genetic methods, it was confirmed that the cysts found in the samples simultaneously with trophozoites actually belong to the species I. cameli. Tubulin cytoskeleton organization of trophozoites and cysts of this species were described for the first time. A striking morphological similarity between species I. cameli and Buxtonella sulcata was demonstrated, including the organization of ciliature. Different isolates of I. cameli and B. sulcata formed a common clade on the phylogenetic tree. The level of evolutionary divergence between the 18 S rRNA sequences of I. cameli, B. sulcata and species closest to them according to the results of molecular phylogenetic analysis was estimated. It was demonstrated that the divergence between I. cameli and B. sulcata is extremely low compared to members of other genera included in the analysis. Taxonomic position of I. cameli and B. sulcata was discussed in according to the data of comparative morphology and molecular phylogeny.