Body shape variation of Garra rufa (Heckel) (Teleostei: Cyprinidae) using geometric and morphometric techniques

Organisms can adapt to habitat conditions that ensure their survival. Habitat separation can lead to different populations of body shape during the phenotypic plasticity process. Both traditional and modern (geometric) morphology are being used in fish population studies. In this study, the body shape differences between Garra rufa (Heckel) populations captured in the Jarrahi River (from the Tigris Basin) were investigated using traditional and geometric morphometric methods. The samples were captured from the Rostam Abad, Aghajari and Behbahan tributaries and transferred to the laboratory. For the traditional morphometric analysis, 10 meristic characters and 19 morphometric characters were measured. Geometric morphological information was extracted using 13 landmark points on left side photographs of individual fish. According to the results of the traditional morphometric analysis, there were differences between the three populations in meristic (lateral line scales, predorsal scales, circamucaudal scales) and morphometric (14 of 19 characters) traits. In the geometric morphometric analysis, the major part of the shape variation is due to landmark points in the head region and the dorsal fin base, with the anal fin and caudal peduncle being the most conservative body regions. The populations had significant differences in body shape with populations from Aghajari and Behbahan tributaries being most similar and the Rostam Abad population was different from the two other populations.