A DNA barcoding approach to identify species of Nemacheilidae: a complex family of cypriniform fishes in Iran

Nemacheilian loaches are a group of freshwater fishes which are distributed in many inland waters of Iran. They are complex species from aspects of systematic with many species of this family being morphologically undistinguishable. Due to limitations behind the morphology-based identification of such species, genetic approaches such as DNA barcoding can be helpful to distinguish species, although their genetic relationships are not well determined yet. The present investigation provides data on genetic structure of some species of Nemachilidae including Paraschistura bampurensis, Oxynoemacheilus kiabii and Turcinemacheilus saadii from inland waters of Iran. These species were sequenced for a 652 base pair region of the mitochondrial cytochrome oxidase subunit I gene. All species were identified by cytochrome oxidase subunit I gene sequence. The sequences of P. bampurensis showed that specimens collected from two streams (Shapour and Fahlian, south-west of Iran), with 1.89% within-species Kimura two parameter distance, shared haplotype in neighbor joining tree. The results provided the first genetic evidence for O. kiabii, which has recently been recorded as a new species in Iran, and also cytochrome oxidase subunit I gene data showed that O. kiabii is completely different from other species of Nemacheilidae. The results suggested that cytochrome oxidase subunit I gene sequencing can be used to identify species of Nemachilidae from the Iranian streams. The picture of Nemachilidae is yet incomplete, and this study is one of the first steps towards enhancing genetic understanding of associations among the species of Nemachilidae in Iran. There should also be further attempts in genetic or systematic research to fill data gaps among fish species in Iran to help establishing a global COI barcode database.