Characterization of the Complete Mitochondrial Genome of and Its Phylogenetic Status in Viviparidae.

is an economically important mollusk in China, but detailed insights into its mitochondrial genome remain scarce. In this study, we sequenced and comprehensively analyzed the structural features and selection pressures of the mitochondrial genome. The maximum likelihood method and Bayesian phylogenetic inference method were used to construct a phylogenetic tree of with 21 other species, including gastropods and bivalves. The full-length mitochondrial genome of 17,379 bp was found to include 22 transfer RNA genes, 2 ribosomal RNA genes, and 13 protein-coding genes, exhibiting similarity to the composition and arrangement of mitochondrial genes in other gastropod species. Notably, the Ka/Ks ratios of mitochondrial protein-coding genes (, , , , , , , , , , , , and ) were <1, which indicates that the snail genes of the three genera of the family may have been subjected to strong natural selection pressure during the evolutionary process, so that the number of synonymous mutations (ks) in genes was much more than that of nonsynonymous mutations (ka). Comparative genomic analysis indicated that, apart from the absence of and , the gene composition of shares a high degree of homology with other members of the conical snail family. Phylogenetic analysis demonstrated that the selected species could be classified into two primary clades in which clustered with the Viviparidae family. This study bridges the knowledge gap regarding the mitochondrial genome of and offers valuable insights into the systematic relationships within the Viviparidae family.