Data from: Impact of climate changes from Middle Miocene onwards on evolutionary diversification in Eurasia: insights from the mesobuthid scorpions

The aridification from Middle Miocene onwards has transformed the Asian interior into an arid environment, and the Pleistocene glacial–interglacial oscillations exerted further ecological impact. Therefore, both aridification and glaciation would have considerably influenced the evolution of many mid-latitude species in temperate Asia. Here, we tested this perspective by a phylogeographic study of the mesobuthid scorpions across temperate Asia using one mitochondrial and three nuclear genes. Concordant mitochondrial and nuclear gene trees were obtained, which are consistent with species tree inferred using a Bayesian approach. The age of the most recent common ancestor (MRCA) of all the studied scorpions was estimated to be 12.49 Ma (late Middle Miocene); Mesobuthus eupeus diverged from the clade composing Mesobuthus caucasicus and Mesobuthus martensii in early Late Miocene (10.21 Ma); M. martensii diverged from M. caucasicus at 5.53 Ma in Late Miocene. The estimated MRCA ages of M. martensii and the Chinese lineage of M. eupeus were 2.37 and 0.68 Ma, respectively. Central Asia was identified as the ancestral area for the lineage leading to M. martensii and M. caucasicus and the Chinese lineage of M. eupeus. The ancestral habitat of the genus Mesobuthus is likely to have been characterized by an arid environment; a shift towards more humid habitat occurred in the MRCA of M. martensii and a lineage of M. caucasicus, finally leading to the adaptation of M. martensii to humid environment. Our data strongly support the idea that the stepwise intensified aridifications from Mid-Miocene onwards drove the diversification of mesobuthid scorpions, and suggest that M. martensii and M. eupeus observed today in China originated from an ancestral lineage distributed in Central Asia. Both the colonization and the ensuing evolution of these species in East Asia appear to have been further moulded by Quaternary glaciations.

中新世中期以来的干旱化进程已将亚洲内陆改造为干旱环境，而更新世冰期-间冰期旋回进一步施加了生态影响。因此，干旱化与冰川作用均对温带亚洲众多中纬度物种的演化产生了显著影响。

本研究针对亚洲温带地区的中蝎属（Mesobuthus）蝎子开展系统地理学研究，利用1个线粒体基因与3个核基因验证了上述学术观点。研究获得了与贝叶斯法（Bayesian approach）推断的物种树一致的线粒体基因树与核基因树拓扑结构。所有受试蝎子的最近共同祖先（most recent common ancestor, MRCA）的分化时间估算为12.49 Ma（中中新世晚期）；欧洲中蝎（Mesobuthus eupeus）于晚中新世早期（10.21 Ma）从由高加索中蝎（Mesobuthus caucasicus）与马氏中蝎（Mesobuthus martensii）构成的演化支中分化出来；马氏中蝎与高加索中蝎的分化时间为晚中新世的5.53 Ma。马氏中蝎与中国分布的欧洲中蝎支系的最近共同祖先年代分别估算为2.37 Ma与0.68 Ma。

中亚被确定为马氏中蝎、高加索中蝎支系以及中国分布的欧洲中蝎支系的祖先分布区。中蝎属的祖先栖息地大概率为干旱环境；马氏中蝎与部分高加索中蝎支系的最近共同祖先发生了向更湿润生境的转变，最终使马氏中蝎适应了湿润环境。

本研究数据强烈支持“中新世中期以来逐步增强的干旱化驱动了中蝎属蝎子的物种分化”这一观点，并表明现今中国境内发现的马氏中蝎与欧洲中蝎起源于中亚分布的祖先支系。这些物种在东亚的定殖及其后续演化过程，似乎均受到了第四纪冰川作用的进一步塑造。