Combining morphology and molecular data to improve <i>Drosophila paulistorum</i> (Diptera, Drosophilidae) taxonomic status
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The <i>willistoni</i> species subgroup has been the subject of several studies since the latter half of the past century and is considered a Neotropical model for evolutionary studies, given the many levels of reproductive isolation and different evolutionary stages occurring within them. Here we present for the first time a phylogenetic reconstruction combining morphological characters and molecular data obtained from 8 gene fragments (C<i>OI, COII, Cytb, Adh, Ddc, Hb, kl-3</i> and <i>per</i>). Some relationships were incongruent when comparing morphological and molecular data. Also, morphological data presented some unresolved polytomies, which could reflect the very recent divergence of the subgroup. The total evidence phylogenetic reconstruction presented well-supported relationships and summarized the results of all analyses. The diversification of the <i>willistoni</i> subgroup began about 7.3 Ma with the split of <i>D. insularis</i> while <i>D.paulistorum</i> complex has a much more recent diversification history, which began about 2.1 Ma and apparently has not completed the speciation process, since the average time to sister species separation is one million years, and some entities of the <i>D. paulistorum</i> complex diverge between 0.3 and 1 Ma. Based on the obtained data, we propose the categorization of the former “semispecies” of <i>D. paulistorum</i> as a subspecies and describe the subspecies <i>D. paulistorum amazonian, D. paulistorum andeanbrazilian, D. paulistorum centroamerican, D. paulistorum interior, D. paulistorum orinocan</i> and <i>D. paulistorum transitional.</i>
自20世纪下半叶以来，威利斯氏果蝇（willistoni）物种亚组便成为多项研究的关注对象；鉴于该类群内部存在多重生殖隔离层级与各异的演化阶段，它被视为演化研究的新热带区模式类群。本研究首次结合形态学性状与8个基因片段（COI、COII、Cytb、Adh、Ddc、Hb、kl-3及per）的分子数据，构建了该亚组的系统发育树。对比形态学与分子数据时，发现部分类群间的系统发育关系存在不一致性；此外，形态学数据存在若干未解析的多歧支，这或许反映了该亚组类群的分化时间极晚。总证据法系统发育重建得到了支持度较高的系统发育关系，并整合了所有分析的结果。威利斯氏果蝇亚组的物种分化始于约730万年前，以岛果蝇（D. insularis）的分化为开端；而保利斯塔果蝇复合群（D. paulistorum）的分化历史则晚得多，始于约210万年前，且目前似乎尚未完成物种形成过程——因为姊妹物种间的平均分化时长为100万年，而该复合群内部分类单元的分化时间介于30万至100万年之间。基于本研究获得的数据，我们提议将保利斯塔果蝇复合群原有的"半物种"重新归类为亚种，并正式描述以下6个亚种：保利斯塔果蝇亚马逊亚种（D. paulistorum amazonian）、保利斯塔果蝇安第斯-巴西亚种（D. paulistorum andeanbrazilian）、保利斯塔果蝇中美洲亚种（D. paulistorum centroamerican）、保利斯塔果蝇内陆亚种（D. paulistorum interior）、保利斯塔果蝇奥里诺科亚种（D. paulistorum orinocan）以及保利斯塔果蝇过渡亚种（D. paulistorum transitional）。
