Environmental Futures Research Institute and School of Environment and Science, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
Biodiversity and Geosciences Program, Queensland Museum, South Brisbane, Queensland 4101, Australia.
Biol Lett. 2020 May;16(5):20200040. doi: 10.1098/rsbl.2020.0040. Epub 2020 May 13.
Wallace's Line demarcates the transition between the differentiated regional faunas of Asia and Australia. However, while patterns of biotic differentiation across these two continental landmasses and the intervening island groups (Wallacea) have been extensively studied, patterns of long-term dispersal and diversification across this region are less well understood. Frogmouths (Aves: Podargidae) are a relictual family of large nocturnal birds represented by three extant genera occurring, respectively, in Asia, 'Sahul' (Australia and New Guinea) and the Solomon Islands, thus spanning Wallace's Line. We used new mitochondrial genomes from each of the extant frogmouth genera to estimate the timeline of frogmouth evolution and dispersal across Wallace's Line. Our results suggest that the three genera diverged and dispersed during the mid-Cenozoic between approximately 30 and 40 Mya. These divergences are among the oldest inferred for any trans-Wallacean vertebrate lineage. In addition, our results reveal that the monotypic Solomons frogmouth () is one of the most phylogenetically divergent endemic bird lineages in the southwest Pacific. We suggest that the contemporary distribution of exceptionally deep divergences among extant frogmouth lineages may be explained by colonization of, and subsequent long-term persistence on, island arcs in the southwest Pacific during the Oligocene. These island arcs may have provided a pathway for biotic dispersal out of both Asia and Australia that preceded the formation of extensive emergent landmasses in Wallacea by at least 10 million years.
华莱士线划分了亚洲和澳大利亚具有区别性的区域动物群之间的过渡带。然而，尽管人们对这两个大陆陆地以及其间的岛屿群（华莱士区）的生物分化模式进行了广泛的研究，但对该地区长期扩散和多样化的模式了解较少。蟆口鸱（佛法僧目：蟆口鸱科）是一个古老的大型夜行鸟类家族，由三个现生属组成，分别分布在亚洲、“萨胡尔”（澳大利亚和新几内亚）和所罗门群岛，跨越了华莱士线。我们使用每个现生蟆口鸱属的新线粒体基因组来估计蟆口鸱在华莱士线跨越的进化和扩散时间表。我们的结果表明，这三个属在大约 3000 万至 4000 万年前的中生代中期发生分歧和扩散。这些分歧是任何跨华莱士类脊椎动物谱系中最古老的推测之一。此外，我们的研究结果表明，单种的所罗门蟆口鸱（）是西南太平洋特有鸟类谱系中进化上最具差异的谱系之一。我们认为，现存蟆口鸱谱系中异常深的分歧的当代分布可能是由于在渐新世期间对西南太平洋岛屿弧的殖民化以及随后的长期生存所导致的。这些岛屿弧可能为生物扩散提供了一条途径，这种扩散发生在华莱士区形成广泛的隆起陆地之前至少 1000 万年。
