Estudio comparativo del melanismo en lagartijas del grupo Liolaemus fitzingerii (Liolaemini: Liolaemus)

color patterns and melanism have been focus of evolutionary studies in a wide variety of taxa, including lizards, and are often associated with certain ecological attributes. however, within the genus liolaemus, only some particular aspects of melanism have been studied in a few species of the l. fitzingerii group. populations of these species show different degrees of melanism with respect to both the intensity and location of black pigment, that in some cases have been used as diagnostic characters in different species of this group. the aim of this study was to assess the degree of polymorphism in ventral body and dorsal head melanism in patagonian lizards from the five haploclades of the l. fitzingerii group (which includes all described species, except l. dumerili and l. camarones), to determine patterns of geographic variation and evaluate their usefulness as diagnostic characters. our results show a high degree of polymorphism in both, ventral body and dorsal head melanism in the five haploclades, and in the different geographic regions analyzed. in this group, the melanic characters should be used with caution and in combination with others for diagnostic characters for species delimitation and diagnosis.