The bacterial genus includes at present 14 species that live in cryospheric environments. In this study, we analyzed 101 genomes of with pure cultures obtained from GenBank. They could be classified into 44 species based on average nucleotide identity (ANI) analysis, showing the diversity of . Among these, 19 strains in our laboratory were isolated from the glacier samples in China. The pairwise ANI values of these 19 strains and known species were <95%, indicating that they represented 19 novel species. The comparative genomic analysis showed significant differences in gene content between the two groups with a maximum growth temperature ( ) of ≤ 20°C and a of >20°C. A comprehensive and robust phylogenetic tree, including 14 known species and 19 novel species, was constructed and showed five phylogenetic branches based on 265 concatenated single-copy gene sequences. The parameter had a strong phylogenetic signal, indicating that the temperature adaptation of was largely through vertical transfer rather than horizontal gene transfer and was affected by selection. Furthermore, using polyphasic taxonomy combined with phylogenomic analysis, we proposed 19 novel species of the genus by the following 19 names: sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., sp. nov., and sp. nov. Overall, the taxonomy and genomic analysis can improve our knowledge of phenotypic diversity, genetic diversity, and evolutionary characteristics of .