A novel Gram-stain-negative, strictly aerobic, rod-shaped and agar-hydrolysing bacterium, designated D2(T), was isolated from a marine sediment sample collected from the coast of Weihai, China (37 degrees 31' 59 '' N 122 degrees 03' 47 '' E). The cells were motile by a lateral flagellum. Growth was observed at 10-42 degrees C, at pH 6.0-9.0 and with 0.5-8% (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain D2(T) belonged to the genus Catenovulum, appearing closely related to Catenovulum agarivorans YM01(T) (96.3% 16S rRNA gene sequence similarity) and Catenovulum maritimum Q1(T) (93.9 %). The dominant fatty acids were summed feature 3 (C-16 : (1)omega 7c and/or iso-C-15 : 0 2-OH), C-16 : 0 and C-10 : 0 3-OH. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, two phosphoaminolipids, two unknown lipids and three phospholipids. Ubiquinone 8 (Q-8) was found to be the major respiratory quinone. The DNA G+C content was 40.4 mol%. On the basis of genotypic, phenotypic and phylogenetic evidence, strain D2(T) is presented as a representative of a novel species of the genus Catenovulum, for which the name Catenovulum sediminis sp. nov. is proposed. The type strain is D2(T) (= KCTC 42869(T) = MCCC 1H00129(T)). An emended description of the genus Catenovulum is also provided.