A bacterial strain designated KTW-12(T) was isolated from a reef-building coral in Kenting, Taiwan, and was characterized using a polyphasic taxonomic approach. Strain KTW-12(T) was Gram-negative, semi-transparent, slightly curved rod-shaped, and non-motile. Growth occurred at 15-35 °C (optimum, 30 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0), and with 0.5-6.0 % NaCl (optimum, 2 %). The major cellular fatty acids were summed feature 3 (C₁₆:₁ω7c and/or C₁₆:₁ω6c), C₁₄:₀ and C₁₆:₀. The DNA G+C content was 47.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain KTW-12(T) was most closely related to Vibrio porteresiae MSSRF30(T), with 94.8 % gene sequence similarity. Further multilocus sequence analysis using rpoA, recA and pyrH genes also revealed low levels of sequence similarity (74.6-85.0 %) with all species of the genus Vibrio with validly published names. A multigene phylogenetic tree using concatenated sequences of the four genes (16S rRNA, rpoA, recA and pyrH) elucidated that strain KTW-12(T) occupied a distinct phylogenetic position, forming a long branch that was not clustered with any other known species of the genus Vibrio. Strain KTW-12(T) differed from V. porteresiae MSSRF30(T) in the ability to reduce nitrate to nitrite, hydrolysis of chitin, fermentation of sorbitol and production of arginine dihydrolase, valine arylamidase, cystine arylamidase and N-acetyl-β-glucosaminidase. On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain KTW-12(T) should be classified as representing a novel species, for which the name Vibrio stylophorae sp. nov. is proposed. The type strain is KTW-12(T) ( = BCRC 80105(T) = LMG 25357(T)).