Data from: Vertebrate time-tree elucidates the biogeographic pattern of a major biotic change around the K–T boundary in Madagascar

The geographic and temporal origins of Madagascar's biota have long been in the center of debate. We reconstructed a time-tree including nearly all native nonflying and nonmarine vertebrate clades present on the island, from DNA sequences of two single-copy protein-coding nuclear genes (BDNF and RAG1) and a set of congruent time constraints. Reconstructions calculated with autocorrelated or independent substitution rates over clades agreed in placing the origins of the 31 included clades in Cretaceous to Cenozoic times. The two clades with sister groups in South America were the oldest, followed by those of a putative Asian ancestry that were significantly older than the prevalent clades of African ancestry. No colonizations from Asia occurred after the Eocene, suggesting that dispersal and vicariance of Asian/Indian groups were favored over a comparatively short period during, and shortly after, the separation of India and Madagascar. Species richness of clades correlates with their age but those clades that have a large proportion of species diversity in rainforests are significantly more species-rich. This finding suggests an underlying pattern of continuous speciation through time in Madagascar's vertebrates, with accelerated episodes of adaptive diversification in those clades that succeeded radiating into the rainforests.马达加斯加生物群的地理与时间起源长期以来一直是学界争论的核心议题。本研究基于两个单拷贝编码蛋白核基因（BDNF、RAG1）的DNA序列与一组一致的时间约束条件，重建了涵盖该岛上几乎所有本土非飞行、非海洋脊椎动物类群的时间树（time-tree）。基于类群水平自相关替换速率或独立替换速率计算得到的重建结果均一致表明，本次纳入的31个类群的起源时间可追溯至白垩纪至新生代时期。其中，与南美洲类群构成姊妹群（sister groups）的两个类群年代最为久远，其次是推测起源于亚洲的类群——这类群的年代显著早于占主流的非洲起源类群。始新世之后未出现来自亚洲的殖民事件，这表明亚洲/印度类群的扩散与地理分异（vicariance）事件主要集中在印度与马达加斯加分离期间及分离后不久的一段相对较短的时期内。类群的物种丰富度与其起源年代呈正相关，但那些在热带雨林中拥有较高物种占比的类群，其物种丰富度显著更高。该研究结果表明，马达加斯加脊椎动物类群存在随时间持续发生物种形成（speciation）的潜在模式，而那些成功辐射进入热带雨林生态位的类群，则经历了加速的适应性辐射（adaptive diversification）过程。