AimSpecies age, the elapsed time since origination, can give insight into how species longevity might influence eco‐evolutionary dynamics, which has been hypothesized to influence extinction risk. Traditionally, species' ages have been estimated from fossil records. However, numerous studies have recently used the branch lengths of time‐calibrated phylogenies as estimates of the ages of extant species. This approach poses problems because phylogenetic trees only contain direct information about species identity at the tips and not along the branches. Here, we show that incomplete taxon sampling, extinction and different assumptions about speciation modes can significantly alter the relationship between true species age and phylogenetic branch lengths, leading to high error rates. We found that these biases can lead to erroneous interpretations of eco‐evolutionary patterns derived from comparing phylogenetic age and other traits, such as extinction risk.InnovationFor bifurcating speciation, the default assumption in most analyses of species age, we propose a probabilistic approach based on the properties of a birth–death process to improve the estimation of species ages. Our approach can reduce the error by one order of magnitude under cases of high extinction and a high percentage of unsampled extant species.Main conclusionOur results call for caution in interpreting the relationship between phylogenetic ages and eco‐evolutionary traits, as this can lead to biased and erroneous conclusions. We show that, under the assumption of bifurcating speciation, we can obtain unbiased approximations of species age by combining information from branch lengths with the expectations of a birth–death process.

中文翻译：

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从系统发育树估计物种年龄的挑战


目的物种年龄，即自起源以来所经过的时间，可以让我们深入了解物种寿命如何影响生态进化动态，人们假设生态进化动态会影响灭绝风险。传统上，物种的年龄是根据化石记录来估计的。然而，最近有许多研究使用时间校准的系统发育的分支长度来估计现存物种的年龄。这种方法会带来问题，因为系统发育树只包含有关物种身份的直接信息，而不是沿着分支。在这里，我们表明，不完整的分类单元采样、灭绝和对物种形成模式的不同假设可以显着改变真实物种年龄和系统发育分支长度之间的关系，导致高错误率。我们发现这些偏差可能导致对通过比较系统发育年龄和其他特征（例如灭绝风险）得出的生态进化模式的错误解释。创新对于分叉物种形成（大多数物种年龄分析中的默认假设），我们提出了一种基于的概率方法出生-死亡过程的特性，以改进物种年龄的估计。在高度灭绝和未采样的现存物种比例较高的情况下，我们的方法可以将误差减少一个数量级。主要结论我们的结果呼吁谨慎解释系统发育年龄和生态进化特征之间的关系，因为这可能会导致偏差以及错误的结论。我们证明，在分叉物种形成的假设下，我们可以通过将分支长度的信息与出生-死亡过程的预期相结合来获得物种年龄的无偏近似值。