# The complete mitochondrial genome and phylogenetic analysis of scyphozoan jellyfish Chrysaora chinensis (Cnidaria: Scyphozoa: Pelagiidae) in the coastal sea of Fangchenggang, China

## TL;DR

This paper reports the first complete mitochondrial genome of the jellyfish Chrysaora chinensis and uses it to explore its evolutionary relationships with other jellyfish species.

## Contribution

The study provides the first complete mitogenome of Chrysaora chinensis and reveals its close phylogenetic relationship with other Chrysaora species.

## Key findings

- The mitogenome of C. chinensis is 16,783 bp long with 69% AT content and includes 13 PCGs, 2 rRNA genes, 2 tRNA genes, and an ORF.
- The gene order is similar to other jellyfish species, and phylogenetic analysis shows C. chinensis is closely related to C. pacifica and C. quinquecirrha.
- The findings offer insights into the taxonomy and evolution of scyphozoan jellyfish.

## Abstract

The scyphozoan jellyfish Chrysaora chinensis has been frequently observed in the coastal waters of Fangchenggang, China, in recent years. This study assembled and analyzed the first complete mitochondrial genome (mitogenome) of C. chinensis from next-generation sequencing data. The mitogenome was 16,783 bp in length, exhibited an overall AT content of 69%, and encoded 13 typical protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes (rrnS and rrnL), 2 transfer RNA (tRNA) genes (trnW-tca and trnM-cat), and an additional open reading frame (ORF), dpo. The mitochondrial gene order was largely consistent with that of previously reported jellyfish species. Furthermore, phylogenetic analysis of 13 mitochondrial PCGs from 19 jellyfish species indicated that Chrysaora chinensis is closely related to Chrysaora pacifica and Chrysaora quinquecirrha. These results provided a valuable reference for clarifying the taxonomy, evolutionary relationships, and phylogeography of scyphozoan jellyfish.