Morphospecies does not match DNA barcoding results in a some common Japanese chironomid species

The family Chironomidae is a very abundant group of benthic macroinvertebrates in freshwater environments. In Japan, 1206 morphospecies of Chironomidae have been recorded. We have determined DNA barcodes for 74 species. Among them, 13 species were excluded from discussion, because they were represented by only a single specimen. In 61 species, the morphospecies matched a single species unit in the phylogenetic tree of partial cytochrome c oxidase subunit I (COI) DNA sequences. However, a morphospecies was divided into two species units in three species and two morphospecies were united into a single species unit. These species are commonly found in ditches, ponds, or lakes, so may bias biodiversity monitoring in these water bodies. We have to redefine these species based on morphological as well as molecular phylogenetic features.