Data from: Across the Indian Ocean: a remarkable example of trans-oceanic dispersal in an austral mygalomorph spider

The Migidae are a family of austral trapdoor spiders known to show a highly restricted and disjunct distribution pattern. Here, we aim to investigate the phylogeny and historical biogeography of the group, which was previously thought to be vicariant in origin, and examine the biogeographic origins of the genus Moggridgea using a dated multi-gene phylogeny. Moggridgea specimens were sampled from southern Australia and Africa, and Bertmainus was sampled from Western Australia. Sanger sequencing methods were used to generate a robust six marker molecular dataset consisting of the nuclear genes 18S rRNA, 28S rRNA, ITS rRNA, XPNPEP3 and H3 and the mitochondrial gene COI. Bayesian and Maximum Likelihood methods were used to analyse the dataset, and the key dispersal nodes were dated using BEAST. Based on our data, we demonstrate that Moggridgea rainbowi from Kangaroo Island, Australia is a valid member of the otherwise African genus Moggridgea. Molecular clock dating analyses show that the inter-specific divergence of M. rainbowi from African congeners is between 2.27–16.02 million years ago (Mya). This divergence date significantly post-dates the separation of Africa from Gondwana (95 Mya) and therefore does not support a vicariant origin for Australian Moggridgea. It also pre-dates human colonisation of Kangaroo Island, a result which is further supported by the intra-specific divergence date of 1.10–6.39 Mya between separate populations on Kangaroo Island. These analyses provide strong support for the hypothesis that Moggridgea colonised Australia via long-distance trans-Indian Ocean dispersal, representing the first such documented case in a mygalomorph spider.,Maximum likelihood analysisMaximum likelihood analysis was undertaken using RAxML on the BlackBox server for the combined six gene, 4118 character, 36 taxa dataset. COI, H3 and XPNPEP3 partitioned by codons and ITS1, 5.8S, ITS2 and 28S partitioned individually, with the GTR + G model used for all genes. This analysis resolved the genera Moggridgea and Bertmainius as reciprocally monophyletic, with M. rainbowi from KI clearly embedded within the African Moggridgea lineage and sister to M. intermedia (bootstrap value 100) (Fig 1). Furthermore, M. rainbowi formed a monophyletic group, but showed phylogeographic structure, with haplotypes reflecting the two geographic locations (Western River and American River). The MrBayes analysis of the same dataset produced a completely concordant tree.RAxML_tree.pdf,

陷阱蛛科（Migidae）是一类南半球陷阱蛛，其分布模式呈现高度局限且间断的特征。本研究旨在探究该类群的系统发育与历史生物地理学特征——此前学界曾认为其起源于异域分化——并通过带有时间校准的多基因系统发育树，分析莫氏蛛属（Moggridgea）的生物地理起源。本研究采集了产自澳大利亚南部与非洲的莫氏蛛属标本，以及采自西澳大利亚的Bertmainus属（Bertmainus）标本。采用桑格测序（Sanger sequencing）技术构建了一套可靠的六标记分子数据集，涵盖核基因18S rRNA、28S rRNA、ITS rRNA、XPNPEP3及组蛋白H3，以及线粒体基因COI。分别采用贝叶斯法与最大似然法对该数据集进行分析，并通过BEAST软件对关键扩散节点进行定年。基于本研究的数据，我们证实产自澳大利亚袋鼠岛的Moggridgea rainbowi（M. rainbowi）是原本仅分布于非洲的莫氏蛛属的有效成员。分子钟定年分析显示，M. rainbowi与非洲同属物种的种间分化时间介于227万至1602万年前（Mya）。该分化时间显著晚于非洲与冈瓦纳大陆分离的时间（9500万年前），因此不支持澳大利亚莫氏蛛属起源于异域分化的假说；同时该时间早于人类登陆袋鼠岛的时间，这一结论也得到了袋鼠岛不同种群间110万至639万年前的种内分化时间数据的进一步佐证。本研究结果强烈支持莫氏蛛属通过跨印度洋长距离扩散抵达澳大利亚的假说，这也是猛蛛类蜘蛛（mygalomorph spider）中首例被证实的此类扩散事件。

最大似然分析：针对包含6个基因、共4118个特征位点、涵盖36个类群的合并数据集，我们使用RAxML软件在BlackBox服务器上完成最大似然分析。其中，COI、H3及XPNPEP3基因按密码子分区，ITS1、5.8S、ITS2及28S基因单独分区，所有基因均采用GTR+Γ进化模型。本次分析显示莫氏蛛属与Bertmainus属互为单系群，产自袋鼠岛的M. rainbowi明确嵌入非洲莫氏蛛属支系中，并与M. intermedia构成姐妹群（自举支持值为100）（图1）。此外，M. rainbowi形成单系群，但表现出系统地理结构，其单倍型对应两个地理分布位点：西河与美洲河。针对同一数据集的MrBayes分析得到了完全一致的系统发育树。RAxML_tree.pdf