Data from: The impact of phylogenetic dating method on interpreting trait evolution: a case study of Cretaceous–Palaeogene eutherian body-size evolution

The fossil record of the earliest Cenozoic contains the first large-bodied placental mammals. Several evolutionary models have been invoked to explain the transition from small to large body sizes, but methods for determining evolutionary mode of trait change depend on input from tree topology and divergence dates. Different dating methods may therefore affect inference of evolutionary model. Here, we fit models of body mass evolution onto dated phylogenies of Cretaceous and Palaeogene mammals, comparing the effect of dating method on interpretation of evolutionary model. Among traditional palaeontological dating approaches, an Ornstein–Uhlenbeck model with high alpha parameters is recovered as best-fitting when minimum-age dating is used, while branch-sharing methods are highly sensitive to topology. Release or release–radiate models are preferred when Bayesian fossilized birth–death method is used, but when using stochastic cal3 dating of trees, a model of increased evolutionary rate without a release in constraint at the Cretaceous–Palaeogene boundary has highest support. These results demonstrate unambiguously that choice of dating method is critical for interpretation of continuous trait evolution, and that care must therefore be taken to consider these effects in macroevolutionary studies.新生代（Cenozoic）早期的化石记录留存了首批大型胎盘类哺乳动物（placental mammals）。学界已提出多种演化模型以解释体型由小型向大型的转变，但用于推断性状演化模式的方法，需依赖系统发育树拓扑结构（tree topology）与分化时间（divergence dates）的输入数据。因此，不同的定年方法可能会对演化模型的推断结果产生影响。本研究将体重演化（body mass evolution）模型拟合至白垩纪与古近纪哺乳动物的定年系统发育树（dated phylogenies）中，对比了定年方法对演化模型解读的影响。在传统古生物学定年方法范畴内，当采用最小年龄定年法（minimum-age dating）时，拟合效果最优的模型为具有较高α参数（alpha parameters）的奥恩斯坦-乌伦贝克模型（Ornstein–Uhlenbeck model）；而分支共享法（branch-sharing methods）对系统发育树拓扑结构高度敏感。当使用贝叶斯化石生灭法（Bayesian fossilized birth–death method）时，释放模型或释放-辐射模型更受青睐；但当采用随机cal3定年法对树结构进行定年时，支持度最高的模型为演化速率提升但未在白垩纪-古近纪界线（Cretaceous–Palaeogene boundary）处放松演化约束的模型。本研究结果明确表明，定年方法的选择对连续性状演化（continuous trait evolution）的解读至关重要，因此在宏观演化研究（macroevolutionary studies）中必须审慎考量此类影响。