Complete mitochondrial genome of the spadenose shark (Scoliodon macrorhynchos).

We firstly presented the complete mitogenome of the spadenose shark Scoliodon macrorhynchos (Carcharhinidae, Carcharhiniformes). The mitogenome is 16,693 bp long and contains 13 protein-coding genes, two rRNAs, 22 tRNAs and one control region, a typical vertebrate arrangement. The codon usage bias was different between the H-strand and L-strand encoded protein genes. All tRNA genes have the typical cloverleaf secondary structure excepting tRNA-Ser2, in which the dihydrouridine (DHU) arm is replaced by a simple loop with 12 unpaired nucleotides. A termination associated sequence and three conserved sequence blocks (CSB I-III) were identified in the control region, which were considered associating with the replication and transcription of mitogenome.