Objective  Molecular genetics of various Dusky Labiaet-barbel (Semilabeo obscures) was studied.

  Method  The second-generation Illumina Hiseq 4000 high-throughput sequencing technology was employed to determine the sequences of the mitochondrial genomes of different species of S. obscures.

  Result  The length of the individual mitochondrial genome was determined to be 16 598–16 599 bp containing 42.65%–42.7% GC. There were 13 protein-coding genes, 22 tRNA, 2 rRNA (i.e., 12S-rRNA and 16S-rRNA), and one control region. Except for the coded ND6, the values of GC-skew of the genomes were all negative; while those of AT-skew in COXI, ND3 and ND6 were negative as well; but those of AT-skew in others were positive. The 13 protein-coding genes consisted of 3 794 aa with the preference codon (RSCU＞2) including the termination codon Arg (CGA), Gly (GGA), Leu (CTA), Pro (CCA), Ser (TCA) and the termination codon Stp (TAA). These S. obscures appeared to relate most closely with Pseudogyrinocheilus prochilus and somewhat with Ptychidio jordani, Rectoris posehensis and Parasinilabeo assimilis.

  Conclusion  The structures and sequences of the mitochondrial genomes of S. obscures as determined were in line with those of typical fish counterparts.