Molecular evidence for mislabelling and taxonomic redundancy in public records of COI sequences of the genus Lethrinus (Teleostei: Lethrinidae)

Public DNA barcode databases such as GenBank and BOLD are invaluable tools for taxonomic and biodiversity research. However, inconsistencies in species identification and labelling can undermine their reliability, particularly for morphologically similar taxa like Lethrinus, a diverse genus of reef-associated fishes of family Lethrinidae prevalent throughout the Indo-Pacific. This study examines the consistency of species-level identifications in public COI sequence data of Lethrinus using molecular phylogenetic evidence. Over 200 COI sequences, representing more than 30 nominal species of the genus Lethrinus, were retrieved from GenBank and BOLD and used to construct a maximum likelihood (ML) tree in MEGA X. Sequences were annotated by species name and country of origin to detect taxonomic conflicts and potential mislabelling. Lutjanus argentimaculatus was included as an outgroup. The ML tree revealed several instances of taxonomic redundancy and probable misidentification. Sequences labelled as Lethrinus atkinsoni appeared in at least four divergent clades, with representatives from Indonesia, Australia, and the Philippines failing to cluster together, indicating either cryptic diversity or mislabelling. Likewise, L. obsoletus sequences from Micronesia and Australia were found in multiple, non-monophyletic lineages. Unresolved entries such as Lethrinus sp. (e.g., BOLD:AAC1547 from Mozambique and JN311945 from Australia) were placed within established species clades, suggesting unclear or incomplete identifications. Additionally, overlapping clades between nominal species—such as L. rubrioperculatus and L. conchyliatus, or L. olivaceus and L. genivittatus—raised questions regarding the validity of current species boundaries. These results demonstrate notable taxonomic inconsistencies within public COI records of the genus Lethrinus. This underscores the urgent need for rigorous database curation, voucher-backed identifications, and integrative taxonomic frameworks combining morphology, molecular data, and geographic context to ensure accurate species delimitation and dependable molecular reference libraries.