Complete mitochondrial genomes render the Night Heron genus Gorsachius non-monophyletic

In the present study, the complete mitochondrial genomes of three Night Herons from the genus Gorsachius were sequenced. All the complete mitochondrial genomes in this genus exhibit duplications in the region between cytochrome b and 12S ribosomal RNA. In Gorsachius magnificus, the duplicated regions span from the last 108 base pairs of cytochrome b to the control region, which are nearly identical to each other in nucleotide sequences, suggesting they are evolving in concert. In G. goisagi and G. melanolophus, the duplicated control regions were nearly identical in majority portions within each individual, while the first tRNA (Pro) -ND6-tRNA (Glu) and the second Cytb-tRNA (Thr) regions have degenerated into non-coding regions. Phylogenetic analyses with Bayesian inference and maximum likelihood based on the nucleotide sequences of two ribosomal RNA genes and 12 protein coding genes indicate that G. magnificus is not monophyletic with the other two Gorsachius species. These new results provide the fundamental basis for further studies to elucidate their phylogenetic positions and relationships with other genera within the subfamily Ardeinae.