Phylogenomic and molecular marker based studies to clarify the evolutionary relationships amongst species and demarcation of the family and some of its constituent genera.

The family was recently proposed encompassing the genera , , , and . Of these genera, contains >50% of the species. However, species form multiple unrelated clades in phylogenetic trees and their evolutionary relationships are unclear. To clarify the evolutionary relationships of and other species, detailed phylogenomic and comparative analyses were conducted on 38 species with available genomes. In a phylogenomic tree based on 1148 core proteins, all , , , and species, excepting , formed a strongly supported clade representing the family . Five conserved signature indels (CSIs) reported here are also uniquely found in these species, providing robust means for the demarcation of family in molecular terms. In our phylogenomic tree and in the Genomic Taxonomy Database, species formed four distinct clades designated as (containing the type species ), _A, _B and _C. Our analyses have identified 17 novel CSIs which offer means to reliably distinguish species from these clades based upon multiple uniquely shared molecular characteristics. Additionally, we have identified three and seven CSIs specific for the genera and , respectively. All seven -specific CSIs are also shared by , which branches reliably with this genus. Based on the strong phylogenetic and molecular evidence presented here, we are proposing that the genus should be restricted to only the species from clade, whereas the species from _A, _B, and _C clades should be transferred into three novel genera gen. nov., gen. nov. and gen. nov., respectively. Additionally, we are also proposing the transfer of to the genus . The proposed changes, which reliably depict the evolutionary relationships among species, should be helpful in the studies of these organisms.