| Resumo: |
Most animal groups have sexual dimorphism in morphological characters, especially body size. In many cases, sexual dimorphism may be a consequence of a hierarchical social organization within populations. However, polygyny or monogamy may evolve independently of sexual dimorphism. Two Liolaemus species are known to be good model species to study the relationship between sexual dimorphism and sexual social system: Liolaemus tenuis (polygyny) and Liolaemus copiapoensis (monogamy). In this study, I evaluate the morphological variation in the geometric shape of the orbit between sexes in the two species, comparing their social condition (polygyny, monogamy) and applying a geometric morphometrical methodology. The results show morphological differentiation in orbit shape, suggesting potentially adaptative characters associated with social condition. There are variety of possible causes which could explain these differences (e.g., multiple origins of the social system in Liolaemus), which could provide new perspectives; however, the generalized lack of knowledge of social systems in Liolaemus species imposes barriers to new studies on the subject.
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