A reference library of DNA barcodes for the earthworms from Upper Normandy: Biodiversity assessment, new records, potential cases of cryptic diversity and ongoing speciation

•DNA barcode (COI marker) reference library for earthworms from Upper Normandy.•Significant rise in the diversity of the group found in a much studied area.•New way to assess the specific status of intraspecific MOTUs.•Cryptic status of the genetic diversity morphologically confirmed.•Need for a consistent annotation in the literature highlighted with examples.