A Gram-stain-negative, strictly aerobic, motile by one single flagellum, dark-orange pigmented and rod-shaped bacterial strain, designated CAU 1457(T), was isolated from marine sediment in the Republic of Korea and its taxonomic position was investigated by using a polyphasic approach.The isolate grew optimally at 30 degrees C, at pH 6.0 and in the presence of 2% (w/v) NaCl Based on 16S rRNA gene sequences similarity, strain CAU 1457(T) belonged to the genus Sphmgomicrobium and was related most closely to Sphmgomicrobium astaxanthinifaciens JCM 18551(T) (98 2 % similarity).Strain CAU 1457(T) contained ubiquinone-10 as the predominant isoprenoid quinone and 11 -methyl C-(18:1) omega 7c and summed feature 8 (C-(18:1) omega 6c} as the major cellular fatty acids. Triamine sym-homospermidine was detected as the major compound in the polyamine pattern The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, four unidentified glycolipids, one unidentified aminophospholipid, two unidentified phospholipids, one unidentified aminolipid and one unidentified lipid. DNA-DNA relatedness between strain CAU 1457(T) and the closely related strains, Sphmgomicrobium astaxanthinifaciens JCM 18551(T) and Sphmgomicrobium aestuaruvivum KCTC 42286(T) were 32. 7 and 28. 4%, respectively. The DNA G+Ccontent of strain was 68. 8 mol%. The phenotypic, chemotaxonomic and phylogenetic data indicated that strain CAU 1457(T) represents a novel species of the genus Sphmgomicrobium, for which the name Sphmgomicrobium arenosum sp. nov. is proposed. The type strain is CAU 1457(T) (=KCTC 62233(T)=NBRC 113094(T)).