Two novel vibrio isolates (R-40492 T and R-40493 T) originating from the zoanthid Palythoa caribaeorum in Brazil in 2005 were taxonomically characterized by means of a polyphasic approach comprising multilocus sequence analysis (MLSA), DNA-DNA hybridization (DDH), ΔTm analysis and phenotypic characterization. Phylogenetic analysis based on 16S rRNA gene sequences showed that R-40492 T and R-40493 T fell within the genus Vibrio and were most closely related to each other with 99% similarity; similarities of these two novel isolates towards Vibrio neptunius LMG 20536 T, Vibrio coralliilyticus LMG 20984 T, Vibrio nigripulchritudo LMG 3896 T, Vibrio sinaloensis LMG 25238 T and Vibrio brasiliensis LMG 20546 T varied between 97.1 and 98.5%. DDH experiments showed that the two isolates had less than 15% relatedness to the phylogenetically most closely related Vibrio species. R-40492 T and R-40493 T had 55-57% relatedness to each other. The ΔTm between R-40492 T and R-40493 T was 6.12 °6C. In addition, MLSA of concatenated sequences (16S rRNA, ftsZ, gyrB, recA, rpoA, topA, pyrH and mreB; 6035 bp in length) showed that the two novel isolates formed a separate branch with less than 92% concatenated gene sequence similarity towards known species of vibrios. Two novel species are proposed to accommodate these novel isolates, namely Vibrio variabilis sp. nov. (type strain, R-40492 T=LMG 25438 T=CAIM 1454 T) and Vibrio maritimus sp. nov. (type strain, R-40493 T=LMG 25439 T=CAIM 1455 T)., © 2011 IUMS.611230093015Baumann, P., Schubert, R.H.W., Genus I.Vibrio.In Bergey's Manual of Systematic Bacteriology (1984), 1, pp. 518-538. , Edited by N. R. Krieg J. G. Holt. 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