The origin and evolution in the Southern Hemisphere of the Austral teals, consisting of the grey-teal and brown-teal species complexes, remains poorly understood owing to limited molecular data. With the group containing multiple independent examples of flight loss, understanding the evolutionary history of the group is of significant interest for functional genomic studies into the evolution of flightlessness. Here, we present the first whole-mitogenome-based phylogeny of the Austral teals. We show that the group diverged from a common ancestor with mallards in the late Miocene and soon after radiated into the brown-teal and grey-teal lineages, in addition to the widely distributed pintails and green-winged teals. The brown-teal species complex, which includes the volant brown teal, the flight-impaired, sub-Antarctic Auckland Island teal, and the flightless, Chatham Island and sub-Antarctic Campbell Island teals, radiated within the past 0.9–1.8 Myr. The divergence of the extinct Chatham Island teal and the colonization of the Auckland and Campbell Islands occurred from mainland New Zealand. Morphological changes towards flightlessness are also present in the volant brown teal on mainland New Zealand, suggesting that this group was on the pathway to flightlessness, a trend that accelerated in some insular island lineages.

中文翻译：

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南方水鸭（鸟纲：雁形目）的辐射和不会飞的进化


由于分子数据有限，南半球的南方水鸭（由灰-水鸭和棕色-水鸭物种复合体组成）的起源和进化仍然知之甚少。由于该群体包含多个独立的飞行丧失例子，了解该群体的进化历史对于功能基因组研究对不能飞行的进化具有重要意义。在这里，我们提出了第一个基于全线粒体基因组的澳大利亚水鸭的系统发育。我们发现，该群体在中新世晚期与绿头鸭的共同祖先分道扬镳，不久之后又辐射到棕水鸭和灰水鸭谱系，此外还有广泛分布的针尾鸭和绿翅水鸭。棕色-水鸭物种复合体，包括会飞的棕色水鸭、飞行障碍的亚南极奥克兰岛水鸭以及不会飞的查塔姆岛和亚南极坎贝尔岛水鸭，辐射范围在过去 0.9-1.8 密尔。已灭绝的查塔姆岛水鸭的分化以及奥克兰和坎贝尔群岛的殖民化发生在新西兰大陆。新西兰大陆的飞翔的棕色水鸭也出现了无法飞行的形态变化，这表明该群体正处于无法飞行的道路上，这种趋势在一些岛屿谱系中加速了。