Landmark-based geometric analysis of body shape variation and meristic plasticity among populations of Alburnoides idignensis from Tigris River Drainage, Persian Gulf Basin, Iran

To compare body shape variations and meristic plasticity among four populations of Alburnoides idignensis fish from Aab-barik, Aab-Sardeh, Darband and Sarab-e Kayvareh rivers in Tigris River Drainage, Persian Gulf Basin of Iran. Geometric morphometric method was used to compare shape data extracted by recording 15 landmark points on 2-D pictures of 94 specimens collected from the rivers by electrofishing and a seine net. The Principal component analysis, Canonical Variate analysis and MANOVA analysis were used to examine shape differences among the populations. Eight meristic traits including number of lateral line scales (LL), scales above and below LL to ventral fin, pre-dorsal scales, dorsal, anal, pectoral and pelvic branched rays were counted under a stereomicroscope and mean number of the data were compared by Kruskal–Wallis and ANOVA in SPSS software. Significant differences were found among the four populations in all meristic traits but the number of LL scales and in their body shape, separating them from each other. Results revealed that the studied populations have some differences in meristic characters and in the shape and size of the head, body, caudal peduncle and ventral and anal fin position.