Phylogenomics of the critically endangered Harttiella (Siluriformes, Loricariidae) based on complete mitochondrial genomes

Abstract The genus Harttiella , belonging to the armoured catfish family Loricariidae subfamily Loricariinae (Siluriformes), comprises species with narrow geographical ranges, predominantly endemic to river basins in French Guiana and Suriname. Despite recent taxonomic advancements, including the description of new species, Harttiella faces conservation challenges due to its rarity, limited dispersal capacities, and habitat fragmentation. To elucidate the evolutionary history and aid in conservation efforts, we sequenced complete mitochondrial genomes for all known Harttiella species. Our analysis revealed distinctive molecular features, including unique stop codon usage and positioning, potentially serving as molecular synapomorphies for the genus. Phylogenetic reconstructions supported previous findings and highlighted the complex evolutionary relationships within the genus. Furthermore, our study provides foundational genomic resources for developing targeted environmental DNA approaches to monitor and conserve Harttiella populations effectively. These findings contribute to a comprehensive understanding of Harttiella evolution and inform conservation strategies aimed at preserving this unique group of freshwater fish.