Standardized nuclear markers improve and homogenize species delimitation in Metazoa

Species are the fundamental units of life and evolution. Their recognition is essential for science society. Molecular methods have been increasingly used identification animal species, despite several challenges. Here, we explore with genomic data from nine lineages a set nuclear markers, namely metazoan-level universal single-copy orthologs (metazoan USCOs), their use in species delimitation. Our sets include arthropods vertebrates. We various assembly strategies coalescent-based inference as well population admixture analyses phenetic methods. demonstrate that metazoan USCOs distinguish closely related morphospecies consistently outperform classical mitochondrial DNA barcoding discriminating different taxa, judged by comparison delimitations. overcome general shortcomings barcodes, due to standardization across Metazoa, also those other approaches. They accurately assign samples not only lower but higher taxonomic levels. Metazoan provide powerful unifying framework DNA-based delimitation taxonomy animals employment could result more efficient research resources.