Mitogenome of a monotypic genus, Oliotius Kottelat, 2013 (Cypriniformes: Cyprinidae): Genomic characterization and phylogenetic position.

We examined the evolutionary status of the genus Oliotius Kottelat, 2013, clarified the mitogenome structure of Smiliogastrinae, and analyzed its phylogenetic information to provide a reference for the taxonomy, evolutionary genetics, and germplasm identification of Smiliogastrinae. Using next-generation sequencing, the complete mitogenome sequence of the monotypic species Oliotius oligolepis was obtained, annotated, and characterized. The mitogenomic sequences of Smiliogastrinae fish were compared and analyzed, and a phylogenetic tree was constructed. The mitogenome of O. oligolepis was 16,636 base pairs long and contained 22 tRNAs, 13 protein-coding genes, 2 rRNAs, and 1 D-loop. The Smiliogastrinae species exhibited gene arrangement consistency, with slight differences in their genome lengths and compositions. Among the 13 protein-coding genes, ND3 showed the highest polymorphism rate and largest genetic distance. Our phylogenetic analysis showed that the target species O. oligolepis is closely related to Barbodes binotatus. The genus Oliotius is monotypic, and the genus Barbodes is not supported as a monophyletic group. This molecular information provides a foundation for further research on the phylogeny of the genera Oliotius and Barbodes and provides insight into the phylogenetic features of fishes belonging to Smiliogastrinae.