Morphometric character analyses was used to evaluate the status of four populations of the endangered Isfahan toothcarp, Aphanius isfahanensis . A total of 227 specimens were collected from four geographically distinct areas (Hasanabad, Malvajerd, Varzaneh and Zarrihyhy;shahr). The geometric morphometrics methods were used to investigate variation in body shapes in this species. The length-weight relationship is a major factor in fisheries studies and the growth exponential (b) values were more than expected (b=3) in all population, representing a positive allometric pattern. Landmark data of two sexes of the four populations analyzed separately using DFA. DNA was extracted using ammonium acetate method from fin clips and/or parts of the body. The DNA quality was examined by electrophoresis on 1% agarose gel and painted with ethidium bromide. PCR amplification was performed using six pairs of microsatellite primers at annealing temperatures of 53.5-61. PCR products were electrophoresed on 6% achrylamid gel and stained with silver nitrate. All loci were polymorphic. Number of observed alleles were in the range of 3-13. The range of expected heterozygosities in Hasanabad, Malvajerd, Varzaneh and Zarrinshahr populations was 0.725-0.892, 0.827-891, 0.662-0.905 and 0.820-887, respectively. The results of Wilcoxon signed rank test showed that H O and H E were not significantly different among the populations (Z-value= –0.447, p-value = 0.655, Z-value= –0.892, p-value = 0.373 respectively). F IS in Hasanabad, Malvajerd, Varzaneh and Zarrinshahr populations was 0.234, 0.242, 0.185 and 0.36, respectively. Hardy- Wienberg equilibrium and linkage equilibrium between loci showed that Pritchard’s model could be used. Variation in morphology of this species in these areas is likely due to the diversity of environment and geographical separation. Based on observations in the studied traits, populations of Aphanius can be partially separated. In the method of geometric morphometry by analyzing canonical variables and analysis separation functions, there were significant differences between the locations. These differences can present populations of these regions as separate taxa. According to the obtained dendogram, it can be concluded that probably there is an isolated population and the studied populations could be Keyword : Microsatellite ; Genetic structure; Genetic variation ; Geometry; Multivariate analysi cyprinodontidae.
