Geographical and environmental distances influence the divergence of characters among biological populations, especially on a macro spatial scale, making it difficult to interpret the individual contribution of these predictor variables in the process of population differentiation. Anurans are excellent models for multi-character evolutionary studies, due to their low vagility and frequent territoriality, causing certain environmental changes to result in barriers that isolate populations. Accordingly, we propose to test the correlation of environmental and geographical distances in the absence of obvious vicariant barriers with phenotypic and genotypic population characters using, as a study model, an Amazonian litter-frog (Allobates sumtuosus). Combining univariate and multivariate analyses, and Structural Equation Modeling, we tested the general hypotheses that geographical and environmental distances affect the variation in the morphometric, acoustic and genetic characters of this frog along a latitudinal gradient at a fine spatial scale. We found that the latitudinal variation was the most correlated with the variation of the studied characters, with an explanatory force always greater than 78%. Therefore, we suggest that there is a combined effect of latitude and environment on phenotypic characteristics in A. sumtuosus. These factors shape the acoustic characters of this species through pressures on body size, as confirmed by a regression analysis showing that larger body sizes resulted in lower-spectral frequency acoustic signals. This is because the climatic environmental gradient occupied by the species promotes changes in the area-volume relationship of individuals, resulting in larger body sizes towards the Equator. Although we observed a pronounced intrapopulation genetic structure, it was not associated with phenotypic variation. In summary, our study breaks down the stages of speciation for this Amazonian litter-frog, demonstrating that environmental factors lead to changes in the sexual signal due to the variation in body size.

地理和环境距离影响生物种群之间特征的差异，尤其是在宏观空间尺度上，这使得难以解释这些预测变量在种群分化过程中的个体贡献。由于其低的易变性和频繁的地域性，Anurans是多字符进化研究的优秀模型，导致某些环境变化导致隔离种群的障碍。因此，我们建议使用亚马逊凋落物青蛙（Allobates sumtuosus）作为研究模型，在不存在明显的维多利亚族障碍与表型和基因型种群特征的情况下，测试环境和地理距离的相关性。）。结合单变量和多变量分析以及结构方程模型，我们测试了以下一般假设：地理和环境距离会影响青蛙在精细空间尺度上沿纬度梯度的形态，声学和遗传特征的变化。我们发现，经纬度变化与所研究字符的变化最相关，解释力始终大于78％。因此，我们建议纬度和环境对A. sumtuosus表型特征有综合影响。。这些因素通过对人体大小的压力来塑造该物种的声学特征，这通过回归分析证实，该分析表明，较大的人体会导致较低频谱频率的声学信号。这是因为该物种所占据的气候环境梯度促进了个体面积-体积关系的变化，导致朝向赤道的体型更大。尽管我们观察到明显的种群内遗传结构，但它与表型变异无关。总而言之，我们的研究打破了这只亚马逊垃圾蛙的物种形成阶段，表明环境因素会由于体型变化而导致性信号发生变化。