Descriptive osteology of Persian loach (Oxynemacheilius persa)

The hillstream loach subfamily Nemacheilinae is difficult to identify because of difficulties in extracting their morphological traits and they consider being a complex group in terms of taxonomy. Now, their classification established is based on the molecular and osteological grounds. This subfamily comprises 8 genera in Iran and the genus Oxynoemacheilus with 12 species has the most species. Due to lacking any information about the osteological features of the genus Oxynoemacheilus in Iran, this study was conducted to provide some basic osteological characteristics of this genus in Iran by selecting Persian loach (Oxynemacheilius persa). For this purpose, 32 specimens of Persian loach were collected from Ghareh-aghach River (Mond river basin) of Fars Province and 5 their segments were cleared and stained with alizarin red S and alcian blue for osteological examinations and its osteological features was described. The Persian loach showed differences connection of frontal antimers of frontals, connection state of frontal with parietal, development of posterovental process of orbitosphenoid and presence of 5 hyporal bones in compare to O. bergianus and O. angorae that can be considered as osteological characters of this species. Regarding to weakness of morphometric, meristic and color pattern traits for taxonomic study of members of the genus Oxynoemacheilus, the finding of this research can use for future taxonomic studies of this taxon.