Identification key of three Iranian endemic nemachilid species based on the neurocranium features (Identification key of the genus Oxynoemacheilus based on osteological features)

Assessment of a sustainable ecosystem and protection of its genetic resources and biodiversity requires the accurate identification of its species. A major problem about Iranian freshwater fishes is lack of a complete understanding of their taxonomical statue, particularly in terms of family Nemacheilidae. Forty-six percent of nemachilid loaches are endemic that not correctly identified due to lacking a proper identification key. Therefore, this study was attempted to provide an identification key based on osteological features of the neurocranium for three endemic species viz. O. persa, O. kermanshahensis and O. kiabii. For this study, specimens of O. persa, O. kiabii and O. kermanshahensis were collected from their habitat and fixed. Then they cleared and stained for osteological examination. The results showed evident differences in the neurocranium of studied species. The ratio of maximum width of the neurocranium to its length, connection of the frontal antimeres, connection of the frontal to the parietal, presence of an orbital shelf, developing posterior process of the orbitosphenoid, presence of the supratemporal commissure, shape of the prevomer and connection of the prootic can be considered to discrete these species based on the osteological features of the neurocranium as identification key.

Keywords:

Ecosystem , Neurocranium , Oxynoemacheilus , Endemic species , Osteology