Organismal interactions drive the accumulation of diversity by influencing species ranges, morphology, and behavior. Interactions vary from agonistic to cooperative and should result in predictable patterns in trait and range evolution. However, despite a conceptual understanding of these processes, they have been difficult to model, particularly on macroevolutionary timescales and across broad geographic spaces. Here we investigate the influence of biotic interactions on trait evolution and community assembly in monitor lizards (Varanus). Monitors are an iconic radiation with a cosmopolitan distribution and the greatest size disparity of any living terrestrial vertebrate genus. Between the colossal Komodo dragon Varanus komodoensis and the smallest Australian dwarf goannas, Varanus length and mass vary by multiple orders of magnitude. To test the hypothesis that size variation in this genus was driven by character displacement, we extended existing phylogenetic comparative methods which consider lineage interactions to account for dynamic biogeographic history and apply these methods to Australian monitors and marsupial predators. Incorporating both exon-capture molecular and morphological datasets we use a combined evidence approach to estimate the relationships among living and extinct varaniform lizards. Our results suggest that communities of Australian Varanus show high functional diversity as a result of continent-wide interspecific competition among monitors but not with faunivorous marsupials. We demonstrate that patterns of trait evolution resulting from character displacement on continental scales are recoverable from comparative data and highlight that these macroevolutionary patterns may develop in parallel across widely distributed sympatric groups.

中文翻译：

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巨蜥的系统基因组学和竞争在决定体型差异中的作用

有机体相互作用通过影响物种范围、形态和行为来推动多样性的积累。相互作用从对抗性到合作性不等，应该导致性状和范围进化的可预测模式。然而，尽管对这些过程有概念性的理解，但它们很难建模，尤其是在宏观进化时间尺度和广泛的地理空间上。在这里，我们研究了生物相互作用对巨蜥（Varanus）的性状进化和群落组装的影响。监视器是一种标志性的辐射，具有世界性的分布，并且是任何现存陆生脊椎动物属中最大的体型差异。在巨大的科莫多巨蜥 Varanus komodoensis 和最小的澳大利亚侏儒巨蜥之间，巨蜥的长度和质量相差多个数量级。为了检验该属的大小变异是由特征位移驱动的假设，我们扩展了现有的系统发育比较方法，这些方法考虑了谱系相互作用以解释动态生物地理历史，并将这些方法应用于澳大利亚监视器和有袋动物捕食者。结合外显子捕获分子和形态数据集，我们使用组合证据方法来估计现存和已灭绝的蜥蜴之间的关系。我们的研究结果表明，澳大利亚巨蜥群落表现出高度的功能多样性，这是由于监测员之间的大陆范围内种间竞争，而不是与食肉动物的有袋动物之间的竞争。