# Complete Mitochondrial Genome of Chlorogomphus papilio (Odonata: Anisoptera: Chlorogomphidae) and Phylogenetic Analyses

## TL;DR

This study sequenced the mitochondrial genome of Chlorogomphus papilio and used it to explore the evolutionary history and relationships of the Chlorogomphidae family.

## Contribution

The study provides the first complete mitochondrial genome of C. papilio and identifies key evolutionary events shaping the Chlorogomphidae family.

## Key findings

- The mitochondrial genome of C. papilio is 15,251 bp long and includes 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes.
- C. papilio and C. magnificus are sister species, diverging around 58.51 million years ago, likely due to the PETM and Himalayan uplift.
- The study offers molecular markers for future research on the evolution and conservation of Chlorogomphidae.

## Abstract

In this study, we sequenced and analyzed the mitochondrial genome of Chlorogomphus papilio (Ris, 1927). The genome was 15,251 bp in length and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one non-coding region. The mitochondrial phylogenetic tree of Chlorogomphidae, constructed based on 16S rRNA and cox1 genes, indicated that C. magnificus and C. papilio are sister species. Divergence time analyses indicated that Chlorogomphidae originated around 111.04 Ma, with C. papilio diverging from the common ancestor shared with C. magnificus approximately 58.51 Ma, likely influenced by the Paleocene–Eocene Thermal Maximum and the tectonic uplift of the Himalayas. The data obtained from our study could serve as a valuable resource for future research on the evolution and conservation of C. papilio.

This study aimed to elucidate the mitochondrial genome organization of Chlorogomphus papilio and the phylogenetic relationships of Chlorogomphidae. We used the Illumina MiSeq sequencing platform to sequence the mitochondrial genome of C. papilio, which was subsequently assembled, annotated, and analyzed. Bayesian inference, maximum likelihood, and maximum parsimony methods were employed to construct the mitochondrial phylogenetic tree of 25 species of Chlorogomphidae based on 16S rRNA and cox1 genes. We observed that the mitochondrial genome of C. papilio is 15,251 bp in length and includes 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a non-coding control region. All PCGs start with a typical ATN codon. While cox1, cox2, cox3, and nad5 end with an incomplete termination codon (T), the remaining PCGs terminate with TAG. The secondary structure of the 22 tRNAs showed that only the trnS1 gene lacked the dihydrouracil arm (DHU arm), whereas the rest formed a typical cloverleaf structure. Additionally, 32 G-U mismatches were observed in the secondary structure. Phylogenetic analyses indicated that C. papilio and C. magnificus are sister species. Divergence time analyses indicated that Chlorogomphidae originated around 111.04 Ma, with C. papilio diverging from the common ancestor shared with C. magnificus approximately 58.51 Ma. This divergence is likely linked to the Paleocene–Eocene Thermal Maximum (PETM) and the tectonic uplift of the Himalayas, which created warm, humid habitats and contributed to geographic isolation. This study contributes to a better understanding of the mitochondrial genome and phylogeny of C. papilio, providing valuable molecular markers for further genetic studies.