Phylogenomic analysis of the genus : proposal for division of this genus into the emended genus and two novel genera gen. nov. and gen. nov.

The members of the genus are key players in the removal of petroleum hydrocarbons from polluted marine environments. More than half of the species were described in the last decade using 16S rRNA gene phylogeny and genomic-based metrics. However, the 16S rRNA gene identity (<94 %) between some members of the genus suggested their imprecise taxonomic status. In this study, we examined the taxonomic positions of species using 16S rRNA phylogeny and further validated them using phylogenomic-related indexes such as digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), average amino acid identity (AAI), percentage of conserved proteins (POCP) and comparative genomic studies. ANI and dDDH values confirmed that all the species were well described at the species level. The phylotaxogenomic analysis showed that species formed three clades. The inter-clade values of AAI and POCP were less than 70 %. The pan-genome evaluation depicted that the members shared 1223 core genes and its number increased drastically when analysed clade-wise. Therefore, these results necessitate the transfer of clade II and clade III members into gen. nov. and gen. nov., respectively, along with the emended description of the genus .