Evolutionary Tracing and Taxonomic Implications of the Mitochondrial Genome of Gephyrocharax atracaudatus (Meek and Hildebrand, 1912)

Gephyrocharax atracaudatus is a rare freshwater fish in Panama. This study provides a comprehensive analysis of the mitochondrial genome of G. atracaudatus, highlighting its gene composition, codon usage, evolutionary pressures, and phylogenetic relationships. The findings reveal unique evolutionary patterns and divergence times of G. atracaudatus that enhance the understanding of the genetic diversity within Characiformes. The increasing availability of genomic data has prompted taxonomic revisions for numerous Characiformes species, encompassing corrections to species names, subfamily, and family classifications. This study reconfirmed the classification of G. atracaudatus as “Gephyrocharax, Stevardiinae, Stevardiidae, Characiformes”. A cross-analysis model for species differentiation and tracking was established using divergence time comparison and phylogenetic analysis. The results show that G. atracaudatus, Hyphessobrycon roseus and Pristella maxillaris converge on one branch, indicating that the genetic relationship may be the most similar, and it occurred approximately 90.45 Mya in the Cretaceous. This study establishes a robust model framework for understanding the evolution of G. atracaudatus, and correctly determines the biological classification status of G. atracaudatus, providing basic data support for clarifying the evolution mode of Characiformes.