Data from: Body size evolution in mammals: complexity in tempo and mode

Body size correlates with virtually every aspect of species' biology, so understanding the tempo and mode of its evolution is of key importance in macroecology and macroevolution. Here we use body-mass data from 3473 of 4510 extant mammalian species and an almost complete species-level phylogeny to determine the best model of log(body-mass) evolution across all mammals, split taxonomically and spatially. An early-burst model fits better across all mammals than models based on either Brownian motion or an Ornstein-Uhlenbeck process, suggesting that mammals experienced a burst of morphological evolution relatively early in their history followed by slower change subsequently. We also use spatial models to investigate rates of body-mass evolution within ecoregions. These models show that around 50% of the variation in rate can be explained by just a few predictors. High estimated rates are associated with cold, low lying, species-poor, high energy, mainland ecoregions. We conclude that the evolution of mammalian body size has been influenced by a complex interplay among geography, climate and history.

体型几乎与物种生物学的所有维度均存在关联，因此解析其演化的速率与模式，在宏生态学与宏演化研究中具有核心重要性。本研究依托4510种现存哺乳动物中3473种的体质量数据，以及一套近乎完整的物种水平系统发育树，旨在确定适用于所有哺乳动物的体质量对数演化最优模型，并从分类学与空间维度开展拆分分析。相较于基于布朗运动（Brownian motion）或奥恩斯坦-乌伦贝克（Ornstein-Uhlenbeck）过程的演化模型，早爆发模型对所有哺乳动物的适配性更优，这表明哺乳动物在演化早期曾经历一轮形态演化爆发，后续的演化速率则逐渐放缓。本研究同时借助空间模型，探究不同生态区内的体质量演化速率。分析结果显示，演化速率的变异中约有50%可通过少量预测变量予以解释。较高的演化速率估算值，与寒冷、低海拔、物种匮乏、高能量的大陆型生态区显著相关。综上，哺乳动物体型的演化受到地理、气候与历史因素间复杂交互作用的调控。