Bombus cullumanus-an extinct European bumblebee species?

Bombus cullumanus s. str. has attracted some of the greatest conservation concerns among bumblebees in Europe because it might now be extinct. However, there has been long-standing disagreement about whether it is conspecific with other eastern pale-banded bumblebees. We investigate these relationships using new data from DNA (COI) barcodes. The results support a Nearctic rufocinctus-group (Bombus rufocinctus) and a Palaearctic cullumanus-group, the latter with just three species: Bombus semenoviellus, Bombus unicus and B. cullumanus s. l. (including several differently coloured taxa). We conclude that, although any persisting B. cullumanus cullumanus s. str. might be a regional conservation priority within Europe, nevertheless, because the species remains common elsewhere within its range in Asia, globally a higher conservation priority should be given to B. unicus, which is genetically more distinct and appears to have a much smaller population in the Russian Far East.