Validation of two sympatric fish species of Urmia chub, Petroleuciscus ulanus and Urmia bleak, Alburnus atropatenae, based on morphologic characters in Mahabad-Chai River

Due to the presence of taxonomic ambiguity regarding Petroleuciscus ulanus and Alburnus atropatenae and the tendency to treat them as synonyms of each other, this study was conducted to validate these two species by comparing their morphometric and meristic characters in the Mahabad-Chai River, Urmia Lake basin. A total of 64 specimens of P. ulanus and 68 specimens of A. atropatenae were sampled and were then investigated for 17 morphometric and 7 meristic characters. Measurements were standardized to eliminate the effects of size due to allometric growth pattern, then their normality and abnormality were examined. Standardized data were analyzed using t-test, Mann-Whitney, principal component analysis (PCA) and discriminative function analysis based on P-value of Hotelling's t-test (DFA/Hotelling's T-test) methods. The results showed that the two species were significantly different in 11 morphometric and 2 meristic traits (P<0.05). DFA analysis also showed significance differences between the two studied species. Our results refute the synonymy hypothesis of Petroleuciscus ulanus and Alburnus atropatenae on the basis of morphometric and meristic traits. Therefore, based on the results of this study, the taxonomic identities of these two species are valid.