Comparative Study of morphological characteristics of different populations of big head goby Ponticola gorlap in the Caspian Sea Basin using geometric morphometric and truss network system methods

Functional morphological traits allow researchers to obtain fundamental information about biology, ecology and biogeography of fishes. Hence, this study was aimed to compare the morphological characteristics of different populations of Ponticola gorlap in 6 ecosystems in Iran [Tonekabon River (1), Siahrood (2), Khairud (3), Babolrood, (4), Gisum (5) and Sefidrood (6)] using geometric morphometric method. In total 17 landmarks were made on the photographs taken from the left side of the 155 fish to extract data from body for geometric morphometric analysis (GPA) using digitization TpsDig2 software. The coordinate data after GPA superimposing, analyzed using principal component analysis (PCA), canonical variate analysis (CVA) and cluster analysis (CA) and body shape pattern of every population was visualized in relation to consensus shape of total populations. In group classification using DFA, 80. 8% of the specimens were correctly classified into their original population and fish populations of 6 stations were different from each other. The CVA and PCA morphometric of P. gorlap indicated that populations have significant differences and they were separated from each other (p<0. 0001). The results of UPGMA cluster test also showed complete separation of populations in terms of morphometry.