Variação na forma das larvas de duas espécies de Pithecopus Cope, 1866 (Anura - Phyllomedusidae) e sua relação com fatores intrínsecos

Abstract

Pithecopus ayeaye and P. megacephalus are species of a genus of anurans with complex taxonomy, not closely related, that possess genetic and geographic structuring. Larval characters have already proven useful for the understanding of evolution and phylogenetic relationships within the genus Pithecopus, but the limits of intraspecific and interspecific variation still need further investigation. Morphological variation in tadpoles occurs due to a combination of intrinsic and extrinsic (abiotic and biotic) factors. It was investigated here, through geometrics morphometrics, the limits of tadpole shape variation in these two species and its relationship to intrinsic factors (i.e., species, development and growth, population and local structuring) in addition to the relationship between growth and development. For this purpose, a large sampling was carried out covering the entire occurrence of these species and all larval ontogenetic stages. To explore the distribution of intrinsic factors in morphological space Principal Component Analysis was conducted; the relationship between developmental stages and size through Kruskal-Wallis and Dunn's tests was evaluated; the effect of size on shape through Allometric Regressions was evaluated; we evaluate the distinction of species by shape through Discriminant Analysis; the effect of population structuring on shape through PERMANOVAs was evaluated; the effect of local structuring on shape through Mantel tests was evaluated. The species have shown a high intraspecific variation that overlaps them in morphological space, but their differences make it possible to distinguish them with a high-accuracy rate and are maintained during development. There was a positive association between growth and development and shape variation could be associated to all the intrinsic factors evaluated, with different intensities among species. The greater variability presented by P. ayeaye may indicate a greater phenotypic plasticity in this species.