Garra , a cyprinid genus, is found throughout Africa to southeastern Asia. This genus contains 103 species among which four species including Garra rufa (Heckle 1843), G. rossica (Nikol‘skii, 1900), G. persica (Berg 1913), and G. varabilis (Heckle 1843) were reported from Iran. In this study 485 specimen of G. rufa from 28 population from six basins including Maharloo, Karkheh, Karun, Tigris, Bushehr and Hormuz basins were fixed in 10% formalin and transferred to the fishery laboratory of the Isfahan University of Technology for Ichthyological investigations. A few live individuals were also traorted to the laboratory for Karyological studies. 28 morphometric, 25 morphometric proportion and 10 meristic traits were examined. Different mean comparison methods, parametric and non-parametric, and Principal Component Analysis (PCA) were used for statistical analyses. In comparison of the six afore mentioned basins, for the morphometric proportions, Kruskal-Wallis H non-parametric test and for all the other traits, analysis of variance (ANOVA) but the ratios dorsal fin base/standard length and pectoral fin/standard length, showed significant differences (P 0.05). The result of KMO=0.65 and Bartlett (P 0.05) tests confirmed the suitability of the data proportions for factorial analysis. Based on the correlation matrix of the studied traits, 8 factors were extracted with total variance of %71.25, having special values more than 1. Plotting of the first factor against the second one showed high overlaps, but partly segregated Bushehr basin from other basins. To compare meristic traits, number of scales above and below the lateral line, dorsal, anal pectoral, pelvic and caudal fin rays, predorsal and circum-caudal peduncle scales, number of vertebra and pharyngeal teeth were used. Except the number of vertebra, caudal fin rays and pharyngeal teeth, all other traits were significantly different. KMO = 0.79 and Bartlett (P 0.05) tests, confirmed the suitability of meristic traits for factor analysis. Based on correlation matrix of meristic traits, the number of three factors with total variance of %51.78 and Eigenvalues more than 1 were extracted. Plotting the first factor against the second one, partly segregated Bushehr basin from other basins, but other basins are highly overlaped. The number of chromosomes in G. rufa obtained as 2n = 48 by counting 50 metaphas plates. In order to prepare karyotype from the best metaphase plates, pictures were taken and chromosomes short and long arm sizes, arms ratio, chromosomes relative lengh, total chromosome length and centromeric indices were calculated. Choromosome formulae was obtained as 34 Metasentric, 12 submetacenric Key words: Morphology, G. rufa , Morphometric traits, Meristic traits, Karyology
