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The genus Salinivibrio,belonging to the family Vibrionaceae,within the class Gammaproteobacteria,was described in 1996 by Mellado et al.to reclassify the species Vibrio costicola based on the comparison of the 16S rRNA gene sequences.Currently,this genus includes four species,one of them with three subspecies.They are moderately halophilic bacteria widely distributed in hypersaline environments,especially in aquatic systems,as well as on salted meats and brines.During the study of the biodiversity in different hypersaline habitats from Spain(Alicante,Canary Islands,Granada,Huelva and Mallorca)and Puerto Rico,a total of 80 strains belonging to the genus Salinivibrio were isolated in different seasons.These strains and the type strains of the species of the genus Salinivibrio were subjected to a phylogenetic,taxonomic and biogeographic study.As an alternative to 16S rRNA gene sequence comparison we propose a Multilocus Sequence Analysis(MLSA)based on the following housekeeping genes: gyrB,recA,rpoD and rpoA.To validate the MLSA as a technique for the delineation of new species in this genus,the results were correlated with studies of DNA-DNA hybridization and genomic studies using massive sequencing.On the other hand,in order to analyze whether the strains isolated from the same environment and phylogenetically closely related have banding patterns that allow differentiating and detecting possible recombination events between species of Salinivibrio,we performed a DNA fmgerprinting analysis.The MLSA study permitted us to distinguish five phylogroups,showing that the three subspecies of S.costicola do not form a monophyletic group.Furthermore,some phylogroups clearly separated from the rest supported by high bootstrap values and they could constitute new species of the genus Salinivibrio.The results obtained from the fingerprinting study showed that strains that are phylogenetically very closely related have different pattern bands,indicating that they constitute different clones.Therefore,differences were observed in the tree topology with respect to the MLSA study which could indicate the existence of frequent horizontal gene transfer events in the genus Salinivibrio.