Late Cenozoic climate change led to the progressive aridification of Australia over the past 15 million years. This gradual biome turnover fundamentally changed Australia's ecosystems, opening new niches and prompting diversification of plants and animals. One example are termites of the Australian Amitermes group (AAG), consisting of the Australian Amitermes and affiliated genera. Although the most speciose and diverse higher termite group in Australia, little is known about its evolutionary history. We used ancestral range reconstruction and diversification analyses to illuminate 1) phylogenetic relationships of the AAG, 2) biogeographical processes leading to the current continent-wide distribution and 3) timing and pattern of diversification in the context of late Cenozoic climate change. By estimating the largest time-calibrated phylogeny for this group to date, we demonstrate monophyly of the AAG and confirm that their ancestor arrived in Australia ~11–10 million years ago (Mya) from Southeast Asia. Ancestral range reconstruction indicates that Australia's monsoon region was the launching point for a continental radiation shaped by dispersal and within-biome speciation rather than vicariance. We found that multiple arid-zone species diversified from mesic and tropical ancestors in the Plio-Pleistocene, but also observed diversification in the opposite direction. Finally, we show that diversification steadily increased from ~8 to 9 Mya during the ‘Hill Gap' and accelerated from ~4 Mya in concert with major ecological change during the Pliocene. Consistent with rapid diversification, species accumulation then slowed down into the present, likely caused by progressive niche saturation. This study provides a stepping stone for predicting future responses of Australia's termite fauna in the face of human-mediated climate change.

中文翻译：

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新生代晚期气候变化期间澳大利亚阿米特梅斯群的快速多样化

新生代晚期气候变化导致澳大利亚在过去 1500 万年中逐渐干旱化。这种逐渐的生物群落更替从根本上改变了澳大利亚的生态系统，开辟了新的生态位并促进了动植物的多样化。一个例子是澳大利亚Amittermes群 (AAG) 的白蚁，由澳大利亚Amittermes和附属属。尽管是澳大利亚种类最多、种类最多的高等白蚁群，但对其进化历史知之甚少。我们使用祖先范围重建和多样化分析来阐明 1）AAG 的系统发育关系，2）导致当前大陆范围分布的生物地理过程和 3）在晚新生代气候变化背景下多样化的时间和模式。通过估计该组迄今为止最大的时间校准系统发育，我们证明了 AAG 的单一性，并确认他们的祖先在大约 11-1000 万年前（Mya）从东南亚到达澳大利亚。祖先范围重建表明，澳大利亚的季风区是由扩散和生物群落内物种形成而不是替代形成的大陆辐射的发射点。我们发现在上更新世，多个干旱区物种从中纪和热带祖先多样化，但也观察到相反方向的多样化。最后，我们表明，在“Hill Gap”期间，多样化从~8 Mya稳步增加到9 Mya，并随着上新世期间的重大生态变化从~4 Mya加速。与快速多样化一致，物种积累随后放缓到现在，这可能是由渐进性生态位饱和引起的。这项研究为预测​​澳大利亚白蚁动物群在人类介导的气候变化方面的未来反应提供了垫脚石。我们表明，在“Hill Gap”期间，多样化从~8 Mya稳步增加到9 Mya，并随着上新世期间的重大生态变化从~4 Mya加速。与快速多样化一致，物种积累随后放缓到现在，这可能是由渐进性生态位饱和引起的。这项研究为预测​​澳大利亚白蚁动物群在人类介导的气候变化方面的未来反应提供了垫脚石。我们表明，在“Hill Gap”期间，多样化从~8 Mya稳步增加到9 Mya，并随着上新世期间的重大生态变化从~4 Mya加速。与快速多样化一致，物种积累随后放缓到现在，这可能是由渐进性生态位饱和引起的。这项研究为预测​​澳大利亚白蚁动物群在人类介导的气候变化方面的未来反应提供了垫脚石。