A Gram-stain-negative, strictly aerobic, rod- or oval-shaped, motile, non-spore-forming bacterium, designated strain CC-AMHB-3(T), was isolated from coastal surface seawater off Hualien, Taiwan. The novel strain showed high pairwise 16S rRNA gene sequence similarities to Ruegeria mobilis NBRC 101030(T) (96.5%), Ruegeria scottomollicae LMG 24367(T) (96.4%), Phaeobacter aquaemixtae SSK6-1(T) (96.2%), Phaeobacter daeponensis TF-218(T) (96.2%), Cribrihabitans marinus CZ-AM5(T) (96.1%) and other species of the family Rhodobacteraceae (? 95.9%). However, strain CC-AMHB-3(T) formed a distinct phyletic lineage associated with C. marinus CZ-AM5(T) during phylogenetic analyses. The polar lipid profile of strain CC-AMHB-3(T) included major amounts of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylcholine; moderate amounts of phosphatidylethanolamine, an unidentified aminolipid, an unidentified phospholipid and an unidentified lipid; and trace amounts of an unidentified lipid and an unidentified phospholipid, which was qualitatively almost in line with that of C. marinus CZ-AM5(T) but remarkably distinct as compared with the type species of the genera Ruegeria (Ruegeria atlantica JCM 21234(T)) and Phaeobacter (Phaeobacter gallaeciensis JCM 21319(T)). In line with the fatty acid profile of C. marinus CZ-AM5(T), the major (>5% of total) fatty acids of strain CC-AMHB-3(T) were C(18:1)�s7c and/or C(18:1)�s6c (summed feature 8), 11-methyl C(18:1)�s7c and C(16:0). The DNA G+C content was 66.7 mol%. Ubiquinone-10 (Q-10) was the sole respiratory quinone. Thus, based on the results of the polyphasic study presented here, strain CC-AMHB-3(T) is considered to represent a novel species of the genus Cribrihabitans, for which the name Cribrihabitans neustonicus sp. nov. is proposed; the type strain is CC-AMHB-3(T) (= JCM 19537(T) =BCRC 80695(T)). In addition, an emended description of the genus Cribrihabitans is also proposed.