School of Earth, Environment and Biological Sciences, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane 4000, Queensland, Australia.
Mol Phylogenet Evol. 2012 Sep;64(3):513-23. doi: 10.1016/j.ympev.2012.05.006. Epub 2012 May 18.
With well over 700 species, the Tribe Dacini is one of the most species-rich clades within the dipteran family Tephritidae, the true fruit flies. Nearly all Dacini belong to one of two very large genera, Dacus Fabricius and Bactrocera Macquart. The distribution of the genera overlap in or around the Indian subcontinent, but the greatest diversity of Dacus is in Africa and the greatest diversity of Bactrocera is in south-east Asia and the Pacific. The monophyly of these two genera has not been rigorously established, with previous phylogenies only including a small number of species and always heavily biased to one genus over the other. Moreover, the subgeneric taxonomy within both genera is complex and the monophyly of many subgenera has not been explicitly tested. Previous hypotheses about the biogeography of the Dacini based on morphological reviews and current distributions of taxa have invoked an out-of-India hypothesis; however this has not been tested in a phylogenetic framework. We attempted to resolve these issues with a dated, molecular phylogeny of 125 Dacini species generated using 16S, COI, COII and white eye genes. The phylogeny shows that Bactrocera is not monophyletic, but rather consists of two major clades: Bactrocera s.s. and the 'Zeugodacus group of subgenera' (a recognised, but informal taxonomic grouping of 15 Bactrocera subgenera). This 'Zeugodacus' clade is the sister group to Dacus, not Bactrocera and, based on current distributions, split from Dacus before that genus moved into Africa. We recommend that taxonomic consideration be given to raising Zeugodacus to genus level. Supportive of predictions following from the out-of-India hypothesis, the first common ancestor of the Dacini arose in the mid-Cretaceous approximately 80mya. Major divergence events occurred during the Indian rafting period and diversification of Bactrocera apparently did not begin until after India docked with Eurasia (50-35mya). In contrast, diversification in Dacus, at approximately 65mya, apparently began much earlier than predicted by the out-of-India hypothesis, suggesting that, if the Dacini arose on the Indian plate, then ancestral Dacus may have left the plate in the mid to late Cretaceous via the well documented India-Madagascar-Africa migration route. We conclude that the phylogeny does not disprove the predictions of an out-of-India hypothesis for the Dacini, although modification of the original hypothesis is required.
带超过 700 个种，族 Dacini 是最种丰富的类群之一在双翅目科 Tephritidae，真正的果蝇。几乎所有的 Dacini 都属于两个非常大的属之一，Dacus Fabricius 和 Bactrocera Macquart。属的分布重叠或围绕印度次大陆，但 Dacus 的最大多样性在非洲，Bactrocera 的最大多样性在东南亚和太平洋。这两个属的单系性尚未得到严格确立，以前的系统发育仅包括少数几个种，而且总是严重偏向于一个属而不是另一个属。此外，这两个属的亚属分类学很复杂，许多亚属的单系性尚未得到明确检验。以前基于形态学综述和当前分类群分布的关于 Dacini 生物地理学的假设提出了一个印度次大陆以外的假说；然而，这在系统发育框架中尚未得到检验。我们试图通过使用 16S、COI、COII 和白眼基因生成的 125 种 Dacini 物种的有时间限制的分子系统发育来解决这些问题。系统发育表明，Bactrocera 不是单系的，而是由两个主要分支组成：Bactrocera s.s. 和“Zeugodacus 亚属群”（一个公认的、但非正式的分类群，由 15 个 Bactrocera 亚属组成）。这个“Zeugodacus”分支是 Dacus 的姐妹群，而不是 Bactrocera，并且根据当前的分布，它在该属进入非洲之前就与 Dacus 分离了。我们建议考虑将 Zeugodacus 提升为属级。支持印度次大陆以外假说的预测，Dacini 的第一个共同祖先出现在白垩纪中期，大约在 8000 万年前。主要的分歧事件发生在印度筏运时期，而 Bactrocera 的多样化显然直到印度与欧亚大陆（50-3500 万年前）连接后才开始。相比之下，Dacus 的多样化，大约在 6500 万年前，显然比印度次大陆以外假说的预测更早开始，这表明，如果 Dacini 起源于印度板块，那么祖先 Dacus 可能在白垩纪中期到晚期通过有文献记载的印度-马达加斯加-非洲迁移路线离开板块。我们的结论是，系统发育并没有否定印度次大陆以外假说对 Dacini 的预测，尽管需要对原始假说进行修改。
