Padrões morfológicos em famílias de anuros do bioma Caatinga: influência filogenética e ecológica

Abstract

Anurans exhibit a great morphological diversity, which is associated with different aspects of their lifestyle and locomotion. Previous studies indicate that the morphology of these organisms may reflect both adaptations to the environment, such as more rounded bodies and shorter limbs in regions of water stress, and more elongated forms with longer limbs in humid áreas, as well as evolutionary history, since phylogenetically closely related species tend to exhibit similar morphological traits. However, these patterns have not yet been systematically analyzed in the Caatinga biome. This study aims to investigate the relationship between anuran morphology and environmental factors in the Caatinga, assessing whether species’ body size and shape are influenced by ecology and the evolutionary history of the group. For this purpose, morphological data from 928 specimens belonging to 81 species, 29 genera, and 10 families of anurans inhabiting the biome were used in two complementary approaches: one at the intertaxonomic level, focusing on patterns of shape and size among families and genera, and the other exploring ecogeographic variation at the intraspecific level, considering species with broad distributions within the biome. The results reveal that, on a macroevolutionary scale, the morphological variation in Caatinga anurans is shaped by climatic and ecological factors, showing little divergence among closely related lineages, greater diversification in more speciose lineages, and convergence among distantly related lineages. Thermal seasonality and rainfall regimes influence body shape and size, favoring larger species in environments with greater thermal variation. On an intraspecific scale, there is a pattern of morphological variation among ecoregional populations, with body shape being the main axis of differentiation. The variations mainly involve cephalic and limb structures. These results reflect the ecological heterogeneity of the Caatinga and highlight morphology as a relevant attribute for understanding the evolutionary relationships of the group in the biome.