Phenotypic integration between claw and toepad traits promotes microhabitat specialization in the Anolis adaptive radiation

The performance of an organism in its environment frequently depends more on its composite phenotype than on individual phenotypic traits. Thus, understanding environmental adaptation requires investigating patterns of covariation across functionally related traits. The replicated adaptive radiations of Greater Antillean Anolis lizards are characterized by ecological and morphological convergence, thus, providing an opportunity to examine the role of multiple phenotypes in microhabitat adaptation. Here, we examine integrated claw and toepad morphological evolution in relation to habitat partitioning across the adaptive radiations of Greater Antillean anoles. Based on analysis of 428 specimens from 57 species, we found that different aspects of claw morphology were associated with different perch dimensions, with claw height positively associated with perch diameter and claw curvature positively associated with perch height. Patterns of integration also varied across claw and toepad traits, likely driven by correlative selection for performance on smoother and rougher substrates. Finally, rates of evolution differed between claw and toepad traits, with claw length evolving faster than all other traits despite having no predicted functional importance. Our results highlight the multivariate nature of phenotypic adaptation and suggest that phenotypic integration across Greater Antillean anoles is driven by fine‐scale correlative selection based on structural habitat specialization.

生物在其环境中的表现往往更多地取决于其综合表型而非单个表型特征。因此，理解环境适应性需要研究功能相关性状之间的协变模式。大安的列斯安乐蜥的重复适应性辐射以生态和形态上的趋同为特征，从而为研究多种表型在微生境适应中的作用提供了机会。在此，我们研究了与大安的列斯安乐蜥适应性辐射过程中的栖息地划分相关的爪和趾垫形态的综合进化。基于对来自57个物种的428个标本的分析，我们发现爪形态的不同方面与不同的栖息维度相关，爪高与栖息直径呈正相关，爪曲率与栖息高度呈正相关。整合模式在爪和趾垫性状之间也存在差异，这可能是由在更光滑和更粗糙基质上的性能相关选择所驱动。最后，爪和趾垫性状的进化速率不同，尽管爪长没有预测的功能重要性，但它比所有其他性状进化得更快。我们的研究结果强调了表型适应的多变量性质，并表明大安的列斯安乐蜥的表型整合是由基于结构栖息地特化的精细尺度相关选择所驱动。