A major goal in evolutionary biology is to determine the mechanisms responsible for maintaining phenotypic variation. Species that have evolved intersexual differences provide an opportunity to increase our understanding of trait evolution. We hypothesize that phenotypic diversity is related to reproductive strategies of female lizards and therefore, to their reproductive potential. Consequently, we evaluated sexual dimorphism in several morphological traits and assessed phenotypic variability and selection on body traits of female lizards in a model species (Tupinambis merianae). The results support our hypothesis that certain phenotypic traits of body shape are sexually dimorphic and that females present large continuous variation in these traits. Moreover, some morphological traits in females favor the increment of energetic reserves and reproductive output. These results contribute to the identification of characters upon which selection may have acted and suggest that phenotypic variation in female lizards are related to a diversity of reproductive strategies. Therefore, we fill part of the knowledge gap on the proximate mechanisms that link maternal morphology and reproductive potential in female lizards.