Toward scalable species descriptions for dark taxa: the role of molecular data.

Species descriptions remain the foundation of biodiversity science, but alpha taxonomy faces a twofold challenge: accelerating the pace of species discovery while ensuring that descriptions produce data that are usable, comparable, and reproducible. This is particularly acute for "dark taxa"-small, hyperdiverse, and morphologically challenging groups-for which morphology-based workflows alone often fail to deliver scalable and reliable identifications. As a result, most species remain undescribed, and many described species are difficult or impossible to identify. We argue that species descriptions must be integrative in a way that meets the practical requirements of modern taxonomy, including scalability, reliable identification, reproducibility, and applicability across life stages. At present, standardized molecular data in the form of DNA barcoding is the only approach that consistently satisfies these criteria. Emerging approaches based on robotics, imaging and artificial intelligence may eventually provide complementary frameworks, but currently lack the standardization and interoperability required for routine application at scale. In contrast, barcode data already enable high-throughput species delimitation, straightforward identification, and direct comparability across studies, supported by global reference libraries and standardized protocols. We therefore propose that DNA barcodes be treated as a baseline component of species descriptions for invertebrates. Standardizing molecular data in taxonomy will accelerate species discovery, improve reproducibility and stability, and ensure that newly described taxa remain accessible in an increasingly DNA-based research landscape.