Brennan Ian G, Oliver Paul M
Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.
Evolution. 2017 May;71(5):1352-1365. doi: 10.1111/evo.13207. Epub 2017 Mar 11.
Trends in global and local climate history have been linked to observed macroevolutionary patterns across a variety of organisms. These climatic pressures may unilaterally or asymmetrically influence the evolutionary trajectory of clades. To test and compare signatures of changing global (Eocene-Oligocene boundary cooling) and continental (Miocene aridification) environments on a continental fauna, we investigated the macroevolutionary dynamics of one of Australia's most diverse endemic radiations, pygopodoid geckos. We generated a time-calibrated phylogeny (>90% taxon coverage) to test whether (i) asymmetrical pygopodoid tree shape may be the result of mass turnover deep in the group's history, and (ii) how Miocene aridification shaped trends in biome assemblages. We find evidence of mass turnover in pygopodoids following the isolation of the Australian continental plate ∼30 million years ago, and in contrast, gradual aridification is linked to elevated speciation rates in the young arid zone. Surprisingly, our results suggest that invasion of arid habitats was not an evolutionary end point. Instead, arid Australia has acted as a source for diversity, with repeated outward dispersals having facilitated diversification of this group. This pattern contrasts trends in richness and distribution of other Australian vertebrates, illustrating the profound effects historical biome changes have on macroevolutionary patterns.
全球和局部气候历史的趋势已与各种生物中观察到的宏观进化模式联系起来。这些气候压力可能单方面或不对称地影响进化枝的进化轨迹。为了测试和比较全球（始新世 - 渐新世边界变冷）和大陆（中新世干旱化）环境变化对一个大陆动物群的影响特征，我们研究了澳大利亚最多样化的特有辐射类群之一——鳞脚蜥虎的宏观进化动态。我们生成了一个时间校准的系统发育树（分类单元覆盖率>90%），以测试（i）不对称的鳞脚蜥虎树形是否可能是该类群历史早期大规模更替的结果，以及（ii）中新世干旱化如何塑造生物群落组合的趋势。我们发现，在约3000万年前澳大利亚大陆板块隔离后，鳞脚蜥虎出现了大规模更替的证据，相反，逐渐干旱化与年轻干旱地区物种形成率的提高有关。令人惊讶的是，我们的结果表明，干旱栖息地的入侵并非进化终点。相反，干旱的澳大利亚一直是多样性的来源，反复向外扩散促进了该类群的多样化。这种模式与其他澳大利亚脊椎动物的丰富度和分布趋势形成对比，并说明了历史生物群落变化对宏观进化模式的深远影响。
