Geographic distributions of the four subspecies of B. variegata and location of the type localities of available names for each (stars). Red: Northern subspecies; yellow: Apennine subspecies; light green: Balkan subspecies; purple: Rhodope subspecies. The dashed and question-marked areas correspond to potential contact zones/introgression and regions of unclear subspecies assignment, respectively. Senior synonyms are shown by big stars and are labelled with capital letters; junior synonyms are shown by small stars and are labelled with numbers.