A Gram-negative, heterotrophic, marine bacterium, designated strain SW-11(T), was isolated from the reef-building coral Isopora palifera in Kenting, Taiwan. Cells were rods and were motile by a single polar flagellum. The strain grew at 10-45 °C (optimum, 30-35 °C), at pH 7.0-8.0 (optimum, pH 7.5) and with 2.0-4.0 % NaCl (optimum, 2.5-3.0 %). The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, diphosphatidylglycerol and four unknown phospholipids. Isoprenoid quinones consisted of ubiquinone 9 (78.8 %) and ubiquinone 8 (21.1 %). Major cellular fatty acids were summed feature 3 (C(16 : 1)ω7c and/or C(16 : 1)ω6c; 22.3 %), C(17 : 1)ω8c (13.4 %), summed feature 8 (C(18 : 1)ω6c and/or C(18 : 1)ω7c; 13.1 %), C(16 : 0) (10.3 %) and anteiso-C(17 : 1)ω9c (10.0 %). The DNA G+C content was 51.6 mol%. 16S rRNA gene sequence analysis indicated that strain SW-11(T) belongs to the class Gammaproteobacteria and is a member of the order Alteromonadales. Strain SW-11(T) shared 93.2 % 16S rRNA gene sequence similarity with Teredinibacter turnerae T7902(T) and 92.1 % with Saccharophagus degradans 2-40(T), and can be further distinguished from these two related strains by distinct patterns of fatty acid content and differences in the polar lipid profile, the ability to utilize different compounds as carbon sources, the ability to degrade various compounds and differences in enzyme activities. The phylogenetic data and those from physiological, morphological and chemotaxonomic characterizations indicate that strain SW-11(T) represents a novel species and genus, for which the name Pseudoteredinibacter isoporae gen. nov., sp. nov. is proposed. The type strain of Pseudoteredinibacter isoporae is SW-11(T) ( = BCRC 17935(T) = LMG 25246(T)).