Data from: Ecological divergence, adaptive diversification, and the evolution of social signaling traits: an empirical study in arid Australian lizards

Species diversification often results from divergent evolution of ecological or social signaling traits. Theoretically, a combination of the two may promote speciation; however empirical examples studying how social signal and ecological divergence might be involved in diversification are rare in general, and typically do not consider range overlap as a contributing factor. We show that ecologically distinct lineages within the Australian sand dragon species complex (including (Ctenophorus maculatus, C. fordi, and C. femoralis) have diversified recently, diverging in ecologically relevant and social signaling phenotypic traits as arid habitats expanded and differentiated. Diversification has resulted in repeated and independent invasion of distinct habitat-types, driving convergent evolution of similar phenotypes. Our results suggest parapatry facilitates diversification in visual signals through reinforcement as a hybridization avoidance mechanism. We show particularly striking variation in visual social signaling traits is better explained by the extent of lineage parapatry relative to ecological or phylogenetic divergence, suggesting these traits reinforce divergence among lineages initiated by ecologically adaptive evolution. This study provides a rare empirical example of a repeated, intricate relationship between ecological and social signal evolution during diversification driven by ecological divergence and the evolution of new habitats. Therefore, supporting emergent theories regarding the importance of both ecological and social trait evolution throughout speciation.

物种多样化（species diversification）通常源于生态或社会信号性状的趋异演化（divergent evolution）。理论上，二者的协同作用可推动物种形成（speciation）；然而总体而言，探究社会信号与生态分化（ecological divergence）如何参与物种多样化的实证案例十分匮乏，且此类研究通常未将分布重叠（range overlap）视为潜在促成因素。

我们的研究表明，澳洲沙龙物种复合体（Australian sand dragon species complex）内的生态分化谱系包括斑澳蜥（Ctenophorus maculatus）、C. fordi及C. femoralis，近期发生了多样化；随着干旱生境（arid habitats）的扩张与分化，这些谱系在生态相关性状与社会信号表型性状上出现了趋异。物种多样化过程中，不同谱系反复且独立地侵入了不同的生境类型，进而驱动了相似表型的趋同演化（convergent evolution）。

我们的研究结果显示，邻域分布（parapatry）可通过作为杂交回避（hybridization avoidance）机制的强化作用（reinforcement），推动视觉信号的多样化。我们发现，相较于生态分化或系统发育分化（phylogenetic divergence），谱系间的邻域分布程度更能解释视觉社会信号性状的显著变异，这表明这类性状强化了由生态适应性演化（ecologically adaptive evolution）所引发的谱系间分化。

本研究为生态分化与新生境演化驱动的物种多样化过程中，生态与社会信号演化之间反复出现的复杂关联提供了罕见的实证案例，从而支持了关于生态与社会性状演化在整个物种形成过程中均具有重要性的新兴理论。