In most cases, the extension process of the assembly worked well. In particular, when the head and tail of a contig had an overlapping region and could not be further extended, this contig could be reasonably connected into a circle. Although several circles were produced during assembly, some problems did arise in the extension process. For example, some contigs were displayed as single lines because their boundaries were too difficult to determine due to poly structures or repeats in the mitogenome. The final assembled results were verified by remapping and some ambiguous regions with low coverage were further checked by PCR. Overall, 19 contigs with a total length of 1,340,105 bp were assembled including 12 circles (ranging from 13.5 to 120.6 kb) and 7 single lines (837,015 bp).