The complete mitochondrial genome and phylogenetic analysis of hydrozoan jellyfish Eirene ceylonensis (Cnidaria, Hydrozoa, Eirenidae) in the coastal sea of Qinhuangdao, China.

Eirene ceylonensis, a hydrozoan jellyfish species with a complex polymorphic life cycle, is widely distributed in the Chinese coastal sea. In this study, we conducted sequencing and analysis of the first complete mitochondrial genome of E. ceylonensis, obtained from the coastal sea of Qinhuangdao, China. The linear mitochondrial genome is 14,997 bp in length with the overall AT content being 72.8%, encoding 13 protein-coding genes (PCGs), two transfer RNA (tRNA) genes ( tRNA-Met and tRNA-Trp ) and two ribosomal RNA (rRNA) genes ( rrnS and rrnL ). Phylogenetic analysis of 13 PCGs suggests that the E. ceylonensis is closely related to Laomedea flexuosa . The availability of the complete mitochondrial genome of E. ceylonensis will be useful for studying the evolutionary relationships of hydrozoan jellyfish species.