Data from: Correlations of life-history and distributional-range variation with salamander diversification rates: evidence for species selection

Evolutionary biologists have long debated the relative influence of species selection on evolutionary patterns. As a test, we apply a statistical phylogenetic approach to evaluate the influence of traits related to species distribution and life-history characteristics on patterns of diversification in salamanders. We use independent contrasts to test trait-mediated diversification while accommodating phylogenetic uncertainty in relationships among all salamander families. Using a neontological data set, we find several species-level traits to be variable, heritable, and associated with differential success (i.e., higher diversification rates) at higher taxonomic categories. Specifically, the macroecological trait of small geographic-range size is strongly correlated with a higher rate of net diversification. We further consider the role that plasticity in life-history traits appears to fulfill in macroevolutionary processes of lineage divergence and durability. We find that pedotypy—wherein some, but not all, organisms of a species mature in the gilled form without metamorphosing—is also associated with higher net diversification rate than is the absence of developmental plasticity. Often dismissed as an insignificant process in evolution, we provide direct evidence for the role of species selection in lineage diversification of salamanders.

进化生物学家长期以来一直在争论物种选择对进化模式的相对影响。为验证相关假说，我们采用统计系统发育方法（statistical phylogenetic approach），评估与物种分布及生活史特征相关的性状对蝾螈类群分化模式的影响。我们通过独立对比法（independent contrasts）检验性状介导的类群分化，同时纳入所有蝾螈科间系统发育关系的不确定性。基于现生生物数据集（neontological data set），我们发现多个物种水平性状兼具变异性与可遗传性，且与高级分类阶元的分化成功率差异（即更高的分化速率）存在关联。具体而言，地理分布范围狭小这一宏观生态性状（macroecological trait）与更高的净分化速率（net diversification rate）显著相关。我们进一步探讨了生活史性状可塑性（plasticity in life-history traits）在谱系分化与存续的宏观进化过程（macroevolutionary processes）中所扮演的角色。我们发现，幼态持续（pedotypy）——即某一物种中部分（而非全部）个体以鳃呼吸形态成熟且不经历变态发育——同样与高于缺乏发育可塑性（developmental plasticity）情形的净分化速率相关。尽管物种选择常被视作进化中无足轻重的过程而遭忽视，我们的研究为物种选择在蝾螈谱系分化中的作用提供了直接实证。