Morphology and Phylogeny of the Microalga Coleochlamys apoda (Microthamniales, Chlorophyta)

— The results of morphological and phylogenetic analysis of Coleochlamys apoda strain ACSSI 377, isolated from the biological soil crust on the surface of a sandy substrate in the North of Russia (Murmansk region) are presented. Morphology is described, including the presence of mature S-shaped cells typical of the species С. oleifera , and formation of synzoospores was reported for the first time for the species. Analysis of the 18S rRNA and rbc L gene sequences indicated that the strain belonged to the species Coleochlamys apoda (order Microthamniales ); this is the first finding of this species found in the Russian territory confirmed by molecular genetic techniques. The presence of clades consisting of uncultured clones on the 18S rRNA gene tree was an indication of the order being insufficiently studied and of the prospects of detection and description of its new members. Ecology and distribution of Coleochlamys and of the sister genus Microthamnion were analyzed based on the literature date and the authors’ observations . Members of the genus Coleochlamys prefer cold habitats and occur within a limited geographic range, in contrast to Microthamnion , which has been repeatedly found in various regions.