# Exploring the mitochondrial genomes and phylogenetic relationships of trans-Andean Bryconidae species (Actinopterygii: Ostariophysi: Characiformes)

## TL;DR

This study explores mitochondrial genomes of Bryconidae fish species to better understand their evolutionary relationships and classification.

## Contribution

The study provides new mitogenome data and phylogenetic insights for trans-Andean Bryconidae species.

## Key findings

- Salminus mitogenomes are significantly larger than others in the study.
- Trans-Andean species form two distinct sister clades based on phylogenetic analysis.
- Current classification of Bryconidae may need revision due to genetic divergence.

## Abstract

Comparative mitogenomics and its evolutionary relationships within Bryconidae remains largely unexplored. To bridge this gap, this study assembled 15 mitogenomes from 11 Bryconidae species, including five newly sequenced. Salminus mitogenomes, exceeding 17,700 bp, exhibited the largest size, contrasting with a median size of 16,848 bp in the remaining species (Brycon and Chilobrycon). These mitogenomes encode 37 typical mitochondrial genes, including 13 protein-coding, 2 ribosomal RNA, and 22 transfer RNA genes, and exhibit the conserved gene arrangement found in most fish species. Phylogenetic relationships, based on the maximum-likelihood method, revealed that the trans-Andean species (found in northwestern South America) clustered into two main sister clades. One clade comprised the trans-Andean species from the Pacific slope, Brycon chagrensis and Chilobrycon deuterodon. The other clade grouped the trans-Andean species from the Magdalena-Cauca Basin Brycon moorei and Salminus affinis, with their respective cis-Andean congeners (found in eastern South America), with Brycon rubricauda as its sister clade. Since the current members of Brycon are split in three separated lineages, the systematic classification of Bryconidae requires further examination. This study provides novel insights into mitogenome characteristics and evolutionary pathways within Bryconidae, standing as crucial information for prospective phylogenetic and taxonomic studies, molecular ecology, and provides a valuable resource for environmental DNA applications.