A culture (designated strain HHS02(T)) was isolated from Chinese prawn (Penaeus chinensis, O'sbeck) and determined to be a member of the genus Vibrio. Strain HHS02(T) comprised slightly curved, rod-shaped, non-endospore-forming, Gram-negative, catalase-negative, oxidase-positive, O/129-sensitive and facultatively anaerobic cells that were motile by means of a single polar flagellum. Growth of strain HHS02(T) occurred in 0.5-7 % (w/v) NaCl [optimally in 1-3 % (w/v) NaCl] and between pH 7.0 and 10.0 (optimally at pH 8.0-9.0). The strain showed growth between 16 and 30 °C (optimum 20 °C). Analysis using the 16S rRNA, gapA, gyrB, mreB, pyrH, recA and topA gene sequences of the novel isolate revealed that the organism belonged to the genus Vibrio, with ∼98, 98, 90, 88, 92, 89 and 83 % sequence similarity, respectively, with representatives of the genus Vibrio. DNA-DNA hybridization experiments indicated that the novel strain was distinct from recognized species of the genus Vibrio. The major fatty acid components were summed feature 3 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH, 38.7 %), C(16 : 0) (22.9 %) and C(18 : 1)ω7c (12.5 %). The G+C content of the genomic DNA was 44.4 mol%. On the basis of the polyphasic taxonomic evidence presented in this study, it is concluded that strain HHS02(T) should be classified as a novel species of the genus Vibrio, for which the name Vibrio atypicus sp. nov. is proposed. The type strain is HHS02(T) (=CGMCC 1.8461(T)=LMG 24781(T)).