Background: DNA barcoding, i.e. the use of a 648 bp section of the mitochondrial gene
cytochrome c oxidase I, has recently been promoted as useful for the rapid identification and
discovery of species. Its success is dependent either on the strength of the claim that interspecific
variation exceeds intraspecific variation by one order of magnitude, thus establishing a "barcoding
gap", or on the reciprocal monophyly of species.