# Comparative Mitogenomics and Phylogeny of Geotrupidae (Insecta: Coleoptera): Insights from Two New Mitogenomes of Qinghai–Tibetan Plateau Dung Beetles

## TL;DR

This study sequenced two new dung beetle mitogenomes from the Qinghai–Tibetan Plateau, revealing conserved genomic features and a clearer phylogenetic framework for the Geotrupidae family.

## Contribution

The study provides the first complete mitogenomes of two high-altitude dung beetles and establishes a well-supported phylogenetic framework for Geotrupidae.

## Key findings

- Conserved gene arrangement and tRNA structures were found across Geotrupidae mitogenomes.
- Strong purifying selection was observed in protein-coding genes, with no evidence of positive selection linked to high-altitude adaptation.
- Phylogenetic analysis resolved key relationships, including Anoplotrupes and Geotrupes as sister genera.

## Abstract

The dung beetle family Geotrupidae (Scarabaeoidea) is crucial for nutrient cycling and soil health, but limited complete mitochondrial genome (mitogenome) data has slowed its phylogenetic and comparative studies. In this work, we obtained the first complete mitogenomes of two high-altitude Geotrupidae species (Geotrupes stercorarius and Phelotrupes auratus) from the Qinghai–Tibetan Plateau. By comparing these new mitogenomes with eight existing ones, we found conserved genomic features (e.g., gene arrangement) in Geotrupidae, while variations appeared in non-coding regions. Evolutionary analyses indicated strong purifying selection on protein-coding genes, with no widespread positive selection linked to high-altitude adaptation. Phylogenetic reconstruction consistently recovered the relationships (Bolboceratinae, (Lethrinae, Geotrupinae)). This study provides precious mitogenomic resources and a clear phylogenetic framework for Geotrupidae.

The dung beetle family Geotrupidae (Scarabaeoidea) plays a vital ecological role in nutrient cycling and soil health, yet the scarcity of complete mitochondrial genome (mitogenome) data has hindered phylogenetic and comparative studies within this family. Here, we sequenced, assembled, and annotated the first complete mitogenomes of Geotrupes stercorarius and Phelotrupes auratus, collected from the Qinghai–Tibetan Plateau. Comparative analysis of these two novel mitogenomes with eight existing mitogenomes revealed conserved architectural features across Geotrupidae, such as gene arrangement, tRNA secondary structures, and small intergenic spacers. Nucleotide composition was largely conserved, though marked divergence occurred at the third codon positions. Substantial structural variation was observed in non-coding regions, particularly in the control region and the nad2-trnW spacer. Evolutionary analyses indicated strong purifying selection across all protein-coding genes, with no evidence of widespread positive selection linked to high-altitude adaptation. Phylogenetic reconstruction consistently recovered the relationships (Bolboceratinae, (Lethrinae, Geotrupinae)), with Anoplotrupes and Geotrupes forming sister genera within Geotrupinae. This study provides additional mitogenomic resources and a well-supported phylogenetic framework for Geotrupidae, resolving key taxonomic uncertainties and establishing a basis for future evolutionary and ecological research.