A polyphasic taxonomic study was performed on strain YM26-026T, which was isolated from acid-treated sediment in Kamaishi, Japan. The bacterial cells were pale-pink-pigmented, Gram-negative, obligately aerobic, non-spore-forming, spherical and non-motile. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate was a member of the phylum ‘Verrucomicrobia’ and shared approximately 84–87 % sequence similarity with strains of the class Opitutae that have been cultivated to date. Strain YM26-026T produced pale-pink pigments of carotenoid. β-Lactam antibiotic susceptibility tests and amino acid analysis of cell-wall hydrolysates indicated that the novel isolate did not contain muramic acid or diaminopimelic acid in the cell wall, suggesting that the strain lacks peptidoglycan. The G+C content of the DNA of strain YM26-026T was 54.0 mol%. Menaquinone-7 was the major quinone and C14 : 0 and C18 : 1 ω9c were the major fatty acids. On the basis of polyphasic taxonomic studies, it was concluded that strain YM26-026T represents a new genus of the family Puniceicoccaceae within the phylum ‘Verrucomicrobia’, for which the name Cerasicoccus arenae gen. nov., sp. nov. is proposed. The type strain is YM26-026T (=MBIC08280T=KCTC 12870T).