The complete mitochondrial genome of Traccatichthys punctulatus (Cypriniformes: Nemacheilidae) and its phylogenetic status.

Traccatichthys punctulatus is a small, colorful and benthic Nemacheilidae species distributed in southern China. Currently, limited published genetic information of Nemacheilidae has hindered the taxonomic research and phylogenetic analysis of this family. In this study, the complete mitochondrial genome (mitogenome) of T. punctulatus was determined using next-generation sequencing. The mitogenome is 16,576 base pairs (bp) in length, comprising 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and 2 non-coding regions: the control region (D-loop) and the origin of light-strand replication (OL). The overall nucleotide base composition is 30.82% A, 25.52% T, 16.36% G, and 27.30% C, with a slightly high A + T content (56.34%). The nucleotide skewness for the full sequence (AT-skew = 0.094, GC-skew = -0.251) is biased toward A and C. Phylogenetic analysis via Bayesian inference (BI) and maximum likelihood (ML) based on concatenated 13 PCGs showed that T. punctulatus clusters with all congeners and occupies a basal position within Traccatichthys, supporting monophyly of Traccatichthys and underscoring distinct evolutionary history of T. punctulatus. This mitogenome may provide rather informative data for species identification and conservation genetics.