Morphometric and meristic differentiations of Garra turcica (Karaman, 1971) from the various branch of the Ceyhan River System, Türkiye

This study was conducted to determine metric and meristic differentiations of Garra turcica Karaman, 1971 inhabiting different branches of the Ceyhan River System. Individuals sampled from 13 branches of the Ceyhan River System were examined for 11 metric and 8 meristic traits. Principal Component Analysis (PCA) and Linear Discriminant Function Analysis (LDFA) identified both for metric and meristic traits among the different branches of Ceyhan River system. SIMPER (Similarity Percentage) test showed that the most important contributions to this differentiation from metric measurements were caudal peduncle length (71.50 %), dorsal fin height (8.04%) and body depth (5.23 %), and from meristic traits were scales on lateral line (41.65 %), scales above lateral line (20.09 %) and pectoral fin rays (8.55 %). It is known that, in inland waters, compared to marine areas, the rate of genetic and morphological differentiation is higher for closer geographical areas, especially due to the inability to migrate and environmental factors. However, it remains a question that needs to be answered as to why the metric and meristic features determined for this species are the ones that are the most influential in the differentiation. In addition, it should be investigated whether the morphological differentiation detected in the current study also occurs at the genetic level. In this case, it may be possible to define a subspecies for this species.