Phenotype plasticity of Bigmouth Lotak, Cyprinion macrostomum Heckel, 1843 from Tigris basin using geometric morphometrics method

The geometric morphometrics method was used to assay the potential phenotypicplasticity between five populations of Bigmouth Lotak (Cyprinion macrostomum).For this purpose, 278 specimens from Tigris basin, including 44, 44, 36, 40 and 43specimens from Sarcham, Homeil, Sikan and Talkhab rivers in Ilam province,respectively and 43 specimens from Moorani river- Lorestan province were collectedusing electrofishing. The specimens were fixed in formalin 4% after anesthetizing inclove oil solution and transformed to the laboratory. Fifteen homologues landmarkpoints were digitized on fish images using tpsDig2 software. The statistical analysis(PCA, CVA and Cluster analysis) of tps data were done using PAST and MorphoJsoftwares. The analysis divided populations into two groups including the Sarcham,Sikan and Homeil and Moorani and Talkhab Rivers. The main considerabledifferences were shorter head length, longer caudal peduncle and anterior position ofpectoral fin in first group. Based on lower water current and water depth in riversgroup 1, it seems that longer caudal peduncle and shorter head length are phenotypeplasticity responses to their habitats. Therefore it can be suggested that BigmouthLotak has a good potential for phenotypic plasticity in response to hydrodynamicconditions.

Keywords:

Phenotype plasticity , Tigris basin , Geometric morphometrics , Bigmouth Lotak , Fishes of Iran