Contributions to the knowledge of DNA barcodes and diversity of intertidal and shallow-water mollusks in the Beagle Channel

Abstract

The Beagle Channel (ca. 55°S) at the southern tip of South America hosts a benthic marine community extensively studied from ecological and morphological perspectives, yet genetic evidence remains sparse and restricted to few taxa. A total of one hundred and twenty-three specimens were sequenced, encompassing three classes of the Phylum Mollusca (Polyplacophora, Gastropoda, and Bivalvia). We evaluated the coverage of our sampled molluscan taxa in public repositories (BOLD and GenBank) and generated new georeferenced COI barcodes from the Beagle Channel. Approximately 30% of specimens could be resolved only to family level owing to limited reference coverage. Twenty-two sequences generated here were not previously represented in BOLD and received new Barcode Index Numbers. Species delimitation and clustering approaches applied to the local dataset revealed discrepancies with a subset of morphological identifications, helping correct biases and enabling more precise, database-consistent assignments. Overall, our work documents the current gaps in barcode representation for mollusks from the Beagle Channel, expands the regional inventory with georeferenced COI records, and provides a practical framework for integrating morphology with DNA barcodes. This study provides a georeferenced COI barcode library for intertidal and shallow-water benthic mollusks from the Beagle Channel, improving taxonomic identifications in public databases and offering a robust baseline for future ecological and eDNA-based monitoring studies in the area.