An eicosapentaenoic acid-producing bacterium, previously described as Shewanella sp. strain SCRC-2738, was classified by phenotypic characterization, chemotaxonomic analysis, 16S rRNA gene sequence analysis and DNA-DNA hybridization. The isolate was Gram-negative, rod-shaped and motile by using polar flagella. The strain grew at 4-32 degrees C; the optimum growth temperature was 27 degrees C. NaCl was required for growth. The major isoprenoid quinones were ubiquinone-7 and ubiquinone-8 and its DNA G+C content was 42.8 mol%. The whole-cell fatty acids mainly (above 5 %) consisted of iso-C(13 : 0), iso-C(15 : 0), C(16 : 0), C(16 : 1)omega7c, C(18 : 1)omega7c and C(20 : 5)omega3 (eicosapentaenoic acid). Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain SCRC-2738T was related closely (sequence similarities above 99 %) to Shewanella marinintestina (99.3 %), Shewanella sairae (99.3 %) and Shewanella schlegeliana (99.2 %). DNA-DNA hybridization and phenotypic characteristics confirmed that strain SCRC-2738T merited classification as a novel species of the genus Shewanella, for which the name Shewanella pneumatophori sp. nov. is proposed. The type strain is SCRC-2738T (=JCM 13187T=NCIMB 14060T).