Single origin of the Mascarene stick insects: ancient radiation on sunken islands?
Single origin of the Mascarene stick insects: ancient radiation on sunken islands?
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DOI：
10.1186/s12862-015-0478-y
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发表时间：
2015-09-16
影响因子：
3.4
通讯作者：
Buckley TR
中科院分区：
文献类型：
--
作者：
Bradler S;Cliquennois N;Buckley TR
将岛屿作为模型系统的研究在理解许多进化过程中发挥着关键作用。了解导致当今岛屿群落的历史事件对于探索物种形成和适应的基本机制至关重要。偏远的马斯克林群岛（毛里求斯、留尼汪岛、罗德里格斯岛）被认为是印度洋从北到南火山活动随年龄增长趋势的产物，拥有极其多样化、特有和受威胁的动植物群，传统上被认为与马达加斯加和非洲的生物地理有关。为了探索麝香竹节虫 (Phasmatodea) 的进化多样性，我们利用代表所有主要竹节虫谱系的 120 多个物种的约 2.4 kb 线粒体和核序列数据构建了全球系统发育。根据获得的时间校准分子树，我们证明马斯克林群岛目前的噬菌体群落由四个可能不相关的传统亚科的成员组成，是来自澳大利亚的一次古代传播事件的结果，并在 16-2900 万年前开始辐射，明显早于毛里求斯的年龄（8-1000 万年）。我们认为，麝香竹节虫在现已被侵蚀的陆地上多样化，大概是在毛里求斯北部。因此，古老的岛屿可能一直存在于印度洋中，直到毛里求斯的出现，它们不仅是海平面低潮时期殖民活动的垫脚石，而且是持久的进化摇篮。这些古老的陆地很可能允许适应性物种形成，并作为重要的多样性来源，为马斯克林群岛和马达加斯加的生物群落做出了贡献。本文的在线版本 (doi:10.1186/s12862-015-0478-y) 包含补充材料，可供授权用户使用。
The study of islands as model systems plays a key role in understanding many evolutionary processes. Knowledge of the historical events leading to present-day island communities is pivotal for exploring fundamental mechanisms of speciation and adaptation. The remote Mascarene archipelago (Mauritius, Réunion, Rodrigues), considered to be the product of an age-progressive trend of north-to-south volcanic activity in the Indian Ocean, hosts a remarkably diverse, endemic and threatened concentration of flora and fauna that has traditionally been considered to be biogeographically related to Madagascar and Africa. To explore the evolutionary diversity of the Mascarene stick insects (Phasmatodea), we constructed a global phylogeny from approximately 2.4 kb of mitochondrial and nuclear sequence data of more than 120 species representing all major phasmatodean lineages. Based on the obtained time-calibrated molecular tree we demonstrate that the current phasmid community of the Mascarene archipelago, which consists of members of four presumably unrelated traditional subfamilies, is the result of a single ancient dispersal event from Australasia and started radiating between 16–29 million years ago, significantly predating the age of Mauritius (8–10 million years). We propose that the Mascarene stick insects diversified on landmasses now eroded away, presumably to the north of Mauritius. In consequence, ancient islands have probably persisted in the Indian Ocean until the emergence of Mauritius and not only served as stepping stones for colonisation events during sea-level lowstands, but as long-lasting cradles of evolution. These ancient landmasses most likely allowed for adaptive speciation and served as significant sources of diversity that contributed to the biomes of the Mascarene archipelago and the megadiverse Madagascar. The online version of this article (doi:10.1186/s12862-015-0478-y) contains supplementary material, which is available to authorized users.