Phenotypic plasticity of the Tuini fish, Capoeta damascina (Actinopterygii: Cyprinidae) populations in Iranian part of Tigris basin using geometric morphometric approach

The Tuini (Capoeta damascina) is one of Freshwater fishes distributing in various habitats. Regarding the ability of this species to inhabit at various environmental conditions, this study was conducted to investigate their common features which able them to reside in different habitats and phenotypic plasticity process among its populations using geometric morphometrics technique. In total 150 specimens of the Tuini fish collected from five different aquatic ecosystem from Iranian part of Tigris basin. Then lateral face of their left side photographed and 17 landmark-points defined and digitized using TpsDig2 software. The coordinate data after GPA superimposing, analyzed using multivariate analyses including principal component, canonical vitiate and cluster analyses. The results revealed a significant difference in the body shape of studied populations associating to snout, head width, the position of pectoral and pelvic fins and depth of caudal peduncle. These differences can show plasticity of these body parts in response to environmental condition of their habitats. Possessing a ventral mouth, head shape and fusiform body shape can be considered to be common characteristics of the Tuini fish reflecting being plastic generalist. Therefore, observed differences in this plastic generalist species have similarities with plastic specialist but with lesser degree indicating an advantage to inhabit in unstable environments i.e. rivers.