Golnaz Sayyadzadeh - Department of Biology, College of Sciences, Shiraz University, Shiraz
Hamid Reza EsmaeiliP - Department of Biology, College of Sciences, Shiraz University, Shiraz

Loach fishes are the second most diverse freshwater fishes of Iran that are classified into two families, Cobitidae and Nemacheilidae with a significant number of the Iranian endemic fish species. During the last few years, many loach specimens from different drainage basins of Iran were collected and their taxonomic status have been widely modified based on morphological and molecular studies especially in the case of endemic species. Based on the obtained results, Cobitidae with four endemic species (total number=6) and Nemacheilidae 25 endemic species (total number=40) are 32% of all freshwater endemic fish species of Iran. However due to several taxonomic problems including small size and interspecific similarities in meristic characters despite of intraspecific differences in body pattern, the taxonomic status of Iranian endemic loach fishes is being modified. In this study, the taxonomic chalanges of this endemic fish species group are discussed during the time. Using different molecular and morphological characters and phylogenetic relationships are suggested items to avoid such taxonomic problems of this diverse group of inland endemic fishes.

Endemic, Taxonomic chalenges, Morphological characters, Molecular characters.