Morphological flexibility of Oxynoemacheilus seyhanensis in different habitats of Turkish inland waters: A case of error in describing a populations as distinct species

This study was conducted to investigate the morphological variation between seven populations of Oxynoemacheilus seyhanensis inhabiting three basins of Turkish inland waters. For this purpose, a total of 71 specimens were collected from Yildizeli, Taşköprü, Suşehri rivers (Kizilirmak basin), Büyükpotuklu, Pinarbaşi and Örenşehir rivers (Seyhan basin) and Akdağmadeni River (Yesilirmak basin). A total of 31 morphometric characteristics were measured. After standardization, data were analyzed using one-way ANOVA and Duncan, Kruskal-Wallis tests, principal component analysis (PCA), canonical variate analysis (CVA), non-parametric MANOVA and cluster analysis. The results showed significant differences in 26 traits between the studied populations of O. seyhanensis (P<0.05) revealing a high morphological flexibility of this deep-bodied species.