Data from: Lineage diversity and size disparity in Musteloidea: testing patterns of adaptive radiation using molecular and fossil-based methods

Adaptive radiation is hypothesized to be a primary mechanism that drives the remarkable species diversity and morphological disparity across the Tree of Life. Tests for adaptive radiation in extant taxa are traditionally estimated from calibrated molecular phylogenies with little input from extinct taxa. With 85 putative species in 33 genera and over 400 described extinct species, the carnivoran superfamily Musteloidea is a prime candidate to investigate patterns of adaptive radiation using both extant- and fossil-based macroevolutionary methods. The species diversity and equally impressive ecological and phenotypic diversity found across Musteloidea is often attributed to 2 adaptive radiations coinciding with 2 major climate events, the Eocene-Oligocene transition and the Mid-Miocene Climate Transition. Here, we compiled a novel time-scaled phylogeny for 88% of extant musteloids and used it as a framework for testing the predictions of adaptive radiation hypotheses with respect to rates of lineage diversification and phenotypic evolution. Contrary to expectations, we found no evidence for rapid bursts of lineage diversification at the origin of Musteloidea, and further analyses of lineage diversification rates using molecular and fossil-based methods did not find associations between rates of lineage diversification and the Eocene-Oligocene transition or Mid-Miocene Climate Transition as previously hypothesized. Rather, we found support for decoupled diversification dynamics driven by increased clade carrying capacity in the branches leading to a subclade of elongate mustelids. Supporting decoupled diversification dynamics between the subclade of elongate mustelids and the ancestral musteloid regime is our finding of increased rates of body length evolution, but not body mass evolution, within the decoupled mustelid subclade. The lack of correspondence in rates of body mass and length evolution suggest that phenotypic evolutionary rates under a single morphological metric, even one as influential as mass, may not capture the evolution of diversity in clades that exhibit elongate body shapes. The discordance in evolutionary rates between body length and body mass along with evidence of decoupled diversification dynamics suggests that body elongation might be an innovation for the exploitation of novel Mid-Miocene resources, resulting in the radiation of some musteloids.

适应性辐射（Adaptive radiation）被假说为驱动生命之树（Tree of Life）各分支显著物种多样性与形态差异的核心机制。传统上，现存类群的适应性辐射检验多基于校准后的分子系统发育树（calibrated molecular phylogenies），几乎未纳入灭绝类群（extinct taxa）的数据。食肉目超科鼬超科（Musteloidea）包含33个属共85个推定物种，以及超过400个已描述的灭绝物种，是同时利用现存类群与基于化石的宏观演化方法（macroevolutionary methods）研究适应性辐射模式的绝佳候选类群。该超科不仅物种多样性丰富，其生态与表型多样性同样引人注目，此前研究常将其归因于两次与重大气候事件同步的适应性辐射：始新世-渐新世转型（Eocene-Oligocene transition）与中新世中期气候转型（Mid-Miocene Climate Transition）。本研究整合构建了涵盖88%现存鼬超科类群的全新时间校准系统发育树（time-scaled phylogeny），并以此为框架，针对与谱系分化速率（rates of lineage diversification）和表型演化速率（rates of phenotypic evolution）相关的适应性辐射假说开展检验。与预期相悖的是，我们未在鼬超科起源处发现谱系快速爆发式分化的证据；进一步结合分子与化石数据的谱系分化速率分析也显示，谱系分化速率与始新世-渐新世转型或中新世中期气候转型之间并未如此前假说所言存在关联。相反，我们发现了解耦分化动态的支持证据：在指向细长型鼬科（mustelids）亚分支的类群支系中，类群承载容量（clade carrying capacity）有所提升。支持细长型鼬科亚分支与原始鼬超科演化体制间存在分化动态解耦的证据还包括：在该解耦的鼬科亚分支中，观测到身体长度的演化速率有所提升，但体重演化速率并未出现类似变化。单一形态学指标（即便像体重这般具有广泛影响力的指标）的演化速率，或许无法完整捕捉具有长体型类群的多样性演化——这一结论由体重与体长演化速率间的不匹配所佐证。体长与体重演化速率的不一致，加上分化动态解耦的相关证据，提示身体延长或许是一种创新性状，帮助类群开发了中新世中期的全新生态位资源，进而推动了部分鼬超科类群的辐射演化。