# The Mitochondrial Genome of the Springtail Semicerura bryophila (Collembola): New Data Call into Question the Relevance of the Subfamilies of the Isotomidae

## TL;DR

This paper analyzes the mitochondrial genome of a springtail species, revealing new insights into the evolutionary relationships within the Isotomidae family.

## Contribution

The study provides the first mitochondrial genome of Semicerura bryophila and challenges the classification of Isotomidae subfamilies.

## Key findings

- The mitochondrial genome of S. bryophila is 15,247 bp long with typical gene content.
- Phylogenetic analysis suggests Anurophorinae is more closely related to Semicerura and Folsomotoma than Isotominae.
- Isotominae is found to be paraphyletic, challenging current taxonomic groupings.

## Abstract

Background: Semicerura bryophila Potapov & Sun, 2020 is a soil-dwelling springtail belonging to the family Isotomidae. The phylogenetic relationships among species of this group remain controversial due to a lack of molecular data. Therefore, in this study, we sequenced the mitochondrial genome of S. bryophila, analyzed the characterization of the mitochondrial genome, and investigated the phylogenetic relationships of Isotomidae. Methods: The mitochondrial genome of S. bryophila was sequenced and assembled. We analyzed the sequence length, nucleotide composition, and evolutionary relationships within the Isotomidae family, incorporating data from twelve previously published mitochondrial genomes. Results: The length of the S. bryophila mitogenome is 15,247 bp and comprises 13 protein-coding genes, 22 tRNAs, and two rRNAs, arranged in a typical order. Its base composition is as follows: A = 38.05%, T = 33.64%, G = 10.17%, and C = 15.03%. Phylogenetic analysis based on the mitogenome revealed that the monophyly of Isotomidae and the paraphyletic grouping of Semicerura and Folsomotoma, supporting their closer relationship with the subfamily Anurophorinae rather than to Isotominae. The analysis validated subfamily Anurophorinae, identified Pachyotominae as a part of Anurophorinae, and suggested that Isotominae is paraphyletic. Conclusions: The present study provides valuable mitochondrial information for the classification of S. bryophila and offers new insights into the taxonomic and evolutionary studies within the genus Semicerura.