Data from: Phylogenetic evidence for mid-Cenozoic turnover of a diverse continental biota

Rapid climatic change at the beginning of the Oligocene epoch is concordant with global biotic turnover in the fossil record. However, while Southern Hemisphere geological movement played a key role in shaping these global climatic shifts, given generally poor terrestrial fossil records, evidence for matching turnover in entire Austral biotas is lacking. Emerging comprehensive phylogenetic frameworks provide alternative avenues to explore for signals of mass turnover or restructuring. Here, we combine phylogenetic data with empirical and simulation-based approaches to understand the temporal dynamics of the origins of a diverse and highly endemic continental biota (Australian lizards and snakes). These analyses indicate that the temporal clustering of major radiation ages in Gondwanan endemic lineages and immigration into Australia is narrower than expected under time-continuous models assuming no overarching external perturbation. Independent phylogenetic dating analyses further indicate that the timing of both processes is concentrated in the period post-dating the Eocene–Oligocene transition (~34 million years ago). Epoch-defining processes around the start of the Oligocene appear to have also played a decisive role in reshaping a diverse Southern Hemisphere biota—by both re-setting Gondwanan endemic diversity and opening the way to successful immigration from the north.

渐新世（Oligocene）初期的快速气候变化，与化石记录中的全球生物更替事件高度契合。尽管南半球的地质运动对这类全球气候转型起到了关键塑造作用，但受限于普遍匮乏的陆地化石记录，目前仍缺乏澳大拉西亚（Austral）全域生物群出现匹配性更替的实证证据。新兴的综合性系统发育研究框架，为探寻大规模生物更替或群落重构的信号提供了全新的研究路径。本研究将系统发育数据与实证研究、基于模拟的分析方法相结合，以解析一个多样性极高且高度特化的大陆生物群——澳大利亚蜥蜴与蛇类——的起源时序动态。分析结果显示：冈瓦纳（Gondwanan）特有支系的主要辐射演化年代，以及生物迁入澳大利亚的事件，其时间聚集性均窄于未考虑外部重大扰动的时间连续模型所预期的结果。独立的系统发育定年分析进一步表明，这两类过程的发生时间均集中于始新世-渐新世过渡（Eocene–Oligocene transition，约3400万年前）之后的时段。塑造渐新世初期面貌的关键过程，同样对重塑南半球多样生物群起到了决定性作用：既重置了冈瓦纳特有类群的多样性水平，也为来自北方的生物成功迁入扫清了障碍。