Abstract
In the present study, we report the complete mitochondrial genome of Jayakar's seahorse, Hippocampus jayakari Boulenger, 1900. The genome of H. jayakari is found to be 16,520 bp in length and has a base composition of A (32.82%), C (23.28%), G (14.13%), and T (29.67%). Similar to other Hippocampus species, it contains a typically conserved structure including 13 protein-coding genes, 2 rRNA genes, 1 control region (D-loop), and 22 tRNA genes. The protein-coding genes had ATG or GTG as the initiation codon and only 6 genes (COX1, ATP8, ATP6, ND4L, ND5 and ND6) terminated by the complete typical stop codon TAA. The lengths of 12S rRNA and 16S rRNA are 939 bp and 1686 bp, respectively. All tRNA genes typically formed a cloverleaf secondary structure, except for tRNA-Ser containing a dihydrouridine arm replacement loop. Hippocampus jayakari exhibited a relatively distant genetic relationship with other 13 Hippocamupus species according to the phylogenetic analysis. The complete mitochondrial genome sequence provided here would be useful for further understanding the evolution of Hippocamupus and conservation genetics of H. jayakari.