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Abstract：
BACKGROUND: Amblyomma is the third most diversified genus of Ixodidae that is distributed across the Indomalayan, Afrotropical, Australasian (IAA), Nearctic and Neotropical biogeographic ecoregions, reaching in the Neotropic its highest diversity. There have been hints in previously published phylogenetic trees from mitochondrial genome, nuclear rRNA, from combinations of both and morphology that the Australasian Amblyomma or the Australasian Amblyomma plus the Amblyomma species from the southern cone of South America, might be sister-group to the Amblyomma of the rest of the world. However, a stable phylogenetic framework of Amblyomma for a better understanding of the biogeographic patterns underpinning its diversification is lacking.
METHODS: We used genomic techniques to sequence complete and nearly complete mitochondrial genomes -ca. 15 kbp- as well as the nuclear ribosomal cluster -ca. 8 kbp- for 17 Amblyomma ticks in order to study the phylogeny and biogeographic pattern of the genus Amblyomma, with particular emphasis on the Neotropical region. The new genomic information generated here together with genomic information available on 43 ticks (22 other Amblyomma species and 21 other hard ticks-as outgroup-) were used to perform probabilistic methods of phylogenetic and biogeographic inferences and time-tree estimation using biogeographic dates.
RESULTS: In the present paper, we present the strongest evidence yet that Australasian Amblyomma may indeed be the sister-group to the Amblyomma of the rest of the world (species that occur mainly in the Neotropical and Afrotropical zoogeographic regions). Our results showed that all Amblyomma subgenera (Cernyomma, Anastosiella, Xiphiastor, Adenopleura, Aponomma and Dermiomma) are not monophyletic, except for Walkeriana and Amblyomma. Likewise, our best biogeographic scenario supports the origin of Amblyomma and its posterior diversification in the southern hemisphere at 47.8 and 36.8 Mya, respectively. This diversification could be associated with the end of the connection of Australasia and Neotropical ecoregions by the Antarctic land bridge. Also, the biogeographic analyses let us see the colonization patterns of some neotropical Amblyomma species to the Nearctic.
CONCLUSIONS: We found strong evidence that the main theater of diversification of Amblyomma was the southern hemisphere, potentially driven by the Antarctic Bridge\'s intermittent connection in the late Eocene. In addition, the subgeneric classification of Amblyomma lacks evolutionary support. Future studies using denser taxonomic sampling may lead to new findings on the phylogenetic relationships and biogeographic history of Amblyomma genus.
METHODS: We used genomic techniques to sequence complete and nearly complete mitochondrial genomes -ca. 15 kbp- as well as the nuclear ribosomal cluster -ca. 8 kbp- for 17 Amblyomma ticks in order to study the phylogeny and biogeographic pattern of the genus Amblyomma, with particular emphasis on the Neotropical region. The new genomic information generated here together with genomic information available on 43 ticks (22 other Amblyomma species and 21 other hard ticks-as outgroup-) were used to perform probabilistic methods of phylogenetic and biogeographic inferences and time-tree estimation using biogeographic dates.
RESULTS: In the present paper, we present the strongest evidence yet that Australasian Amblyomma may indeed be the sister-group to the Amblyomma of the rest of the world (species that occur mainly in the Neotropical and Afrotropical zoogeographic regions). Our results showed that all Amblyomma subgenera (Cernyomma, Anastosiella, Xiphiastor, Adenopleura, Aponomma and Dermiomma) are not monophyletic, except for Walkeriana and Amblyomma. Likewise, our best biogeographic scenario supports the origin of Amblyomma and its posterior diversification in the southern hemisphere at 47.8 and 36.8 Mya, respectively. This diversification could be associated with the end of the connection of Australasia and Neotropical ecoregions by the Antarctic land bridge. Also, the biogeographic analyses let us see the colonization patterns of some neotropical Amblyomma species to the Nearctic.
CONCLUSIONS: We found strong evidence that the main theater of diversification of Amblyomma was the southern hemisphere, potentially driven by the Antarctic Bridge\'s intermittent connection in the late Eocene. In addition, the subgeneric classification of Amblyomma lacks evolutionary support. Future studies using denser taxonomic sampling may lead to new findings on the phylogenetic relationships and biogeographic history of Amblyomma genus.
摘要：
背景：Amblyomma是分布在Indomalayan的第三大种类的Ixodidae属，非洲热带,澳大利亚（IAA），近地和新热带生物地理生态区，在新神经达到其最高的多样性。在以前发表的线粒体基因组的系统发育树中已经有提示，核rRNA,从两者的组合和形态，即澳大利亚弱视或澳大利亚弱视加上来自南美南部锥体的弱视物种，可能是世界其他地方的Amblyomma的姐妹团体。然而,缺乏稳定的Amblyomma系统发育框架，以更好地了解支撑其多样化的生物地理模式。
方法：我们使用基因组技术对完整和几乎完整的线粒体基因组进行测序。15kb-以及核核糖体簇-约。8kbp-为17个Amblyomma蜱，以研究Amblyomma属的系统发育和生物地理模式，特别强调新热带地区。此处生成的新基因组信息以及43个tick（其他22个Amblyomma物种和其他21个硬tick-作为外部-）上可用的基因组信息用于执行系统发育和生物地理推断的概率方法以及使用生物地理日期的时间树估计。
结果：在本文中，我们提供了迄今为止最有力的证据，表明澳大利亚弱视可能确实是世界其他地区弱视的姐妹群体（主要发生在新热带和非洲热带动物地理区域的物种）。我们的结果表明，所有弱视亚属(Cernyomma，Anastosiella,Xiphiastor，Adenopleura,Aponomma和Dermiomma）不是单系的，除了Walkeriana和Amblyomma.同样，我们最好的生物地理情景支持弱视的起源及其在南半球47.8和36.8Mya的后部多样化，分别。这种多样化可能与南极陆桥结束了澳大利亚和新热带生态区的联系有关。此外，生物地理分析让我们看到了一些新热带弱小物种对近北树的定殖模式。
结论：我们发现了强有力的证据表明，弱视多样化的主要剧院是南半球，可能是由始新世晚期南极桥的间歇性连接驱动的。此外,弱视的亚属分类缺乏进化支持。使用更密集的分类学采样的未来研究可能会导致有关Amblyomma属的系统发育关系和生物地理历史的新发现。
方法：我们使用基因组技术对完整和几乎完整的线粒体基因组进行测序。15kb-以及核核糖体簇-约。8kbp-为17个Amblyomma蜱，以研究Amblyomma属的系统发育和生物地理模式，特别强调新热带地区。此处生成的新基因组信息以及43个tick（其他22个Amblyomma物种和其他21个硬tick-作为外部-）上可用的基因组信息用于执行系统发育和生物地理推断的概率方法以及使用生物地理日期的时间树估计。
结果：在本文中，我们提供了迄今为止最有力的证据，表明澳大利亚弱视可能确实是世界其他地区弱视的姐妹群体（主要发生在新热带和非洲热带动物地理区域的物种）。我们的结果表明，所有弱视亚属(Cernyomma，Anastosiella,Xiphiastor，Adenopleura,Aponomma和Dermiomma）不是单系的，除了Walkeriana和Amblyomma.同样，我们最好的生物地理情景支持弱视的起源及其在南半球47.8和36.8Mya的后部多样化，分别。这种多样化可能与南极陆桥结束了澳大利亚和新热带生态区的联系有关。此外，生物地理分析让我们看到了一些新热带弱小物种对近北树的定殖模式。
结论：我们发现了强有力的证据表明，弱视多样化的主要剧院是南半球，可能是由始新世晚期南极桥的间歇性连接驱动的。此外,弱视的亚属分类缺乏进化支持。使用更密集的分类学采样的未来研究可能会导致有关Amblyomma属的系统发育关系和生物地理历史的新发现。
