sp. nov., a member of the family from lichen-dominated forested tundra.

An isolate of aerobic, Gram-stain-negative, rod-shaped, non-motile and light-pink pigmented bacteria, designated SBC68, was obtained from slightly decomposed thalli of the lichen sp. collected from the forested tundra of north-western Siberia. Cells of this isolate occurred singly, in pairs or in rosettes. These bacteria were acidophilic (optimum growth at pH 4.3-5.6) and mesophilic (optimum growth at 20-30 °C) but were also capable of growth at low temperatures, down to 7 °C. The preferred growth substrates were sugars, some organic acids and lichenan. The major fatty acids were iso-C, Cω7, C, Cω7, and 13,16-dimethyl octacosanedioic acid. The only quinone was MK-8, and the G+C content of the DNA was 54.7 mol%. SBC68 represented a member of the family ; the closest taxonomically described relatives were DHF9 and TPB6028 (97.2 and 97.1 % 16S rRNA gene sequence similarity, respectively). In 16S rRNA gene-based trees, SBC68 clustered together with species of the genus . However, this isolate differed from all previously described species of the genus with respect to the pink pigmentation, formation of cell rosettes and substrate utilization pattern. On the basis of these data, strain SBC68 should be considered to represent a novel species of acidobacteria, for which the name sp. nov. is proposed. The type strain is SBC68 (=DSM 104462=VKM B-3208).