# Based on Mitochondrial Genomes and Gene Order Rearrangements: Phylogenetic Relationships and Terrestrial Adaptability in Paguroidea (Crustacea: Decapoda)

## TL;DR

This study uses mitochondrial genomes to explore the evolutionary relationships and terrestrial adaptation of Paguroidea species, focusing on genetic changes linked to energy metabolism.

## Contribution

The study identifies positive selection in specific mitochondrial genes associated with terrestrial adaptation in Coenobitidae.

## Key findings

- Paguroidea is paraphyletic, with unresolved internal phylogenetic relationships.
- Coenobitidae diverged from aquatic Diogenidae and adapted to terrestrial habitats.
- Positive selection was detected in ATP6, ND3, ND2, ND5, and ND6 genes in Coenobitidae.

## Abstract

The complete mitochondrial genome provides pivotal information that enhances our understanding of molecular phylogenetic analysis, evolution, and gene rearrangement. Anomura, a decapod taxon with exceptional phenotypic diversity, inhabits hydrothermal vents and various aquatic and terrestrial habitats. However, debates regarding the deep‐level phylogeny of Anomura persist, particularly concerning its complex evolutionary relationships. Within this context, the superfamily Paguroidea emerges as a group of significant interest due to its unique biology and potential to illuminate broader anomuran evolutionary questions. Herein, we determined the details of mitogenomes in five Paguroidea species and further investigated phylogenetic relationships and divergence times of Anomura. Our study revealed that Paguroidea is paraphyletic, with its internal relationships still requiring further discussion. Additionally, phylogenetic analyses indicated that Coenobitidae diverged from aquatic Diogenidae and subsequently adapted to terrestrial habitats. Hence, we investigated its mechanisms of genetic rearrangement and conducted a foreground branch selection pressure analysis with Coenobitidae as the focal lineage. Branch‐site selection pressure analysis identified positive selection on ATP6, ND3, ND2, ND5, and ND6. Therefore, we hypothesized that Coenobitidae has increased its energy metabolism through the evolution of these genes, which may be advantageous for its adaptation to terrestrial environments. Our findings provide valuable insights into the evolution of Anomura species and offer a theoretical basis for the conservation and utilization of Anomura genetic resources.

Investigating the internal phylogenetic relationships within Paguroidea and the terrestrial adaptability of Coenobitidae within Paguroidea through the analysis of mitochondrial genomes of five Anomura species.