Calibrating the taxonomy of a megadiverse insect family: 3000 DNA barcodes from geometrid type specimens (Lepidoptera, Geometridae)

It is essential that any DNA barcode reference library be based upon correctly identified specimens. The Barcode of Life Data Systems (BOLD) requires information such as images, geo-referencing, and details on the museum holding the voucher specimen for each barcode record to aid recognition of potential misidentifications. Nevertheless, there are misidentifications and incomplete identifications (e.g., to a genus or family) on BOLD, mainly for species from tropical regions. Unfortunately, experts are often unavailable to correct taxonomic assignments due to time constraints and the lack of specialists for many groups and regions. However, considerable progress could be made if barcode records were available for all type specimens. As a result of recent improvements in analytical protocols, it is now possible to recover barcode sequences from museum specimens that date to the start of taxonomic work in the 18th century. The present study discusses success in the recovery of DNA barcode sequences from 2805 type specimens of geometrid moths which represent 1965 species, corresponding to about 9% of the 23 000 described species in this family worldwide and including 1875 taxa represented by name-bearing types. Sequencing success was high (73% of specimens), even for specimens that were more than a century old. Several case studies are discussed to show the efficiency, reliability, and sustainability of this approach.