A Gram-negative, strictly aerobic, lemon-yellow pigmented, non-motile, rod-shaped strain designated A7G-39(T) was isolated from a yellow coloured marine sponge (Tethya sp.). Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain represented a member of the family Flavobacteriaceae of the phylum Bacteroidetes and that it showed highest sequence similarity (94.1 %) to Algibacter wandonensis WS-MY22(T). The strain could be differentiated phenotypically from recognised members of the family Flavobacteriaceae. The major fatty acids of strain A7G-39(T) were identified as iso-C15:0 3-OH and summed feature 1 (iso-C15:1 H and/or C13:0 3-OH) as defined by the MIDI system. The DNA G+C content was determined to be 32.6 mol%, the major respiratory quinone was identified as menaquinone 7 (MK-7) and a polar lipid profile was present consisting of phosphatidylethanolamine, an unidentified aminolipid and an unidentified lipid. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus for which the name Spongiivirga citrea gen. nov., sp. nov. is proposed. The type strain of S. citrea is A7G-39(T) (=KCTC 32990(T) = NBRC 110022(T)).