Data from: A comprehensive DNA barcode database for Central European beetles with a focus on Germany: adding more than 3,500 identified species to BOLD

Beetles are the most diverse group of animals and are crucial for
ecosystem functioning. In many countries, they are well established for
environmental impact assessment, but even in the well-studied Central
European fauna, species identification can be very difficult. A
comprehensive and taxonomically well-curated DNA barcode library could
remedy this deficit and could also link hundreds of years of traditional
knowledge with next generation sequencing technology. However, such a
beetle library is missing to date. This study provides the globally
largest DNA barcode reference library for Coleoptera for 15 948
individuals belonging to 3514 well-identified species (53% of the German
fauna) with representatives from 97 of 103 families (94%). This study is
the first comprehensive regional test of the efficiency of DNA barcoding
for beetles with a focus on Germany. Sequences ≥500 bp were recovered from
63% of the specimens analysed (15 948 of 25 294) with short sequences from
another 997 specimens. Whereas most specimens (92.2%) could be
unambiguously assigned to a single known species by sequence diversity at
CO1, 1089 specimens (6.8%) were assigned to more than one Barcode Index
Number (BIN), creating 395 BINs which need further study to ascertain if
they represent cryptic species, mitochondrial introgression, or simply
regional variation in widespread species. We found 409 specimens (2.6%)
that shared a BIN assignment with another species, most involving a pair
of closely allied species as 43 BINs were involved. Most of these taxa
were separated by barcodes although sequence divergences were low. Only
155 specimens (0.97%) show identical or overlapping clusters.