First Description of Intergenic Sequences in Corydoradinae and Introducing the Complete Mitogenome of Hoplisoma concolor (Siluriformes: Callichthyidae)

<b>Background/Objectives</b>: In this study, we report the complete mitochondrial genome sequence of <i>Hoplisoma concolor</i> Weitzman, 1961 (Siluriformes: Callichthyidae), a callichthyid catfish. <b>Methods</b>: DNA sequencing was performed to obtain its complete mitogenome using the HiSeq platform. To assess the phylogenetic relationships, maximum-likelihood and Bayesian inference phylogenetic trees were constructed using two ribosomal RNA (rRNA) genes and all protein-coding sequences (PCGs) concatenated from the <i>H. concolor</i> mitogenome, along with 31 other Siluriformes mitogenomes. <b>Results</b>: The complete mitogenome of <i>H. concolor</i> is 16,579 base pairs in length, with a nucleotide composition of 32.2% A, 26.0% T, 15.3% G, and 26.5% C. It contains 13 PCGs, 22 transfer RNA genes, and 2 rRNA genes. Phylogenetic analysis based on all PCGs and two rRNAs of the complete mitogenome confirms <i>H. concolor</i> as a sister species of <i>H. panda</i> within the subfamily Corydoradinae. In addition, intergenic sequences between <i>atp6</i> and <i>cox3</i> of 21 species of Corydoradinae provide further support for their phylogenetic relationship. <b>Conclusions</b>: Given the lack of detailed descriptions regarding the length and nucleotide composition of these intergenic sequences, our study contributes valuable insights into the genetic diversity and evolutionary complexity of Callichthyidae.