Data from: Tracing the diversification history of a Neogene rodent invasion into South America

We investigated spatial patterns of evolutionary relatedness and diversification rates to test hypotheses about the historical biogeographic processes underlying the radiation of Neotropical rats and mice (Sigmodontinae, ~400 species). A negative correlation between mean phylogenetic distance and diversification rates of rodent assemblages reveals a pattern of species co-occurrence in which assemblages of closely related species are also the fastest diversifying ones. Subregions of the Neotropics occupied by distantly related species that are on average more slowly diversifying include Central America, northern South America, and the Atlantic forest. In southern South America, recent species turnover appears to have been higher. Ancestral locations for the main tribes of sigmodontines were also estimated, suggesting eastern South America and the Amazonian lowlands were colonized before some central Andean regions, even though the latter are now centers of species richness for these rodents. Moreover, a past connection between the tropical Andes and the Atlantic Forest is suggested by our results, highlighting a role for a hypothetical arc connecting the two biomes, which would have impacted many other groups of organisms. Whether rapid, recent speciation in some regions is related to Quaternary climatic fluctuations and the young age of sigmodontines (~12.7 Ma crown age) or instead to intrinsic traits of these rodents remains an open question. If the former is true, we hypothesize that contrasting trends will characterize older Neotropical clades.

我们探究了演化亲缘关系与分化速率的空间分布模式，旨在检验支撑新大陆鼠类——棉鼠亚科（Sigmodontinae，约400种）辐射演化的历史生物地理过程相关假说。啮齿类组合的平均系统发育距离与分化速率呈显著负相关，这揭示了一类物种共存模式：亲缘关系紧密的物种所构成的组合，同时也是分化速率最快的类群。新热带区中由亲缘关系较远、平均分化速率较慢的物种占据的亚区域包括中美洲、南美北部与大西洋森林（Atlantic Forest）。南美南部的近期物种更新速率相对更高。研究同时估算了棉鼠亚科主要族的祖先分布地，结果显示：尽管安第斯中部区域如今是这类啮齿类的物种丰富度核心区，但南美东部与亚马孙低地的定殖时间早于部分安第斯中部区域。此外，本研究结果表明热带安第斯山脉与大西洋森林之间曾存在生物区系联系，凸显了连接这两个生物群区的假想弧状廊道的作用——这类廊道大概率对诸多其他生物类群产生了深远影响。部分区域近期的快速物种形成事件，究竟与第四纪气候波动以及棉鼠亚科较年轻的冠群年龄（约12.7 Ma）相关，还是源于这类啮齿类的内在生物学性状，仍是一个尚未解决的科学问题。若前者成立，我们推测较古老的新热带区演化支将呈现截然相反的分布趋势。