Rocha Rita Gomes, Ferreira Eduardo, Loss Ana Carolina, Heller Rasmus, Fonseca Carlos, Costa Leonora Pires
From the Departamento de Biologia and CESAM, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal (Rocha, Ferreira, and Fonseca); Laboratório de Mastozoologia e Biogeografia, Departamento de Ciências Biológicas, Universidade Federal do Espírito Santo, Campus de Maruípe, 29043-900 Vitória, Espírito Santo, Brasil (Rocha, Loss, and Costa); and Instituto Gulbenkian de Ciência, Oeiras, Portugal (Heller).
J Hered. 2015 Sep-Oct;106(5):593-607. doi: 10.1093/jhered/esv058. Epub 2015 Aug 6.
The riverine barrier model suggests that rivers play a significant role in separating widespread organisms into isolated populations. In this study, we used a comparative approach to investigate the phylogeography of 6 didelphid marsupial species in central Brazil. Specifically, we evaluate the role of the mid-Araguaia River in differentiating populations and estimate divergence time among lineages to assess the timing of differentiation of these species, using mitochondrial DNA sequence data. The 6 didelphid marsupials revealed different intraspecific genetic patterns and structure. The 3 larger and more generalist species, Didelphis albiventris, Didelphis marsupialis, and Philander opossum, showed connectivity across the Araguaia River. In contrast the genetic structure of the 3 smaller and specialist species, Gracilinanus agilis, Marmosa (Marmosa) murina, and Marmosa (Micoureus) demerarae was shaped by the mid-Araguaia. Moreover, the split of eastern and western bank populations of the 2 latter species is consistent with the age of Araguaia River sediments formation. We hypothesize that the role of the Araguaia as a riverine barrier is linked to the level of ecological specialization among the 6 didelphid species and differences in their ability to cross rivers or disperse through the associated habitat types.
河流屏障模型表明，河流在将分布广泛的生物分隔成孤立种群方面发挥着重要作用。在本研究中，我们采用比较方法调查了巴西中部6种袋鼬科有袋动物的系统地理学。具体而言，我们利用线粒体DNA序列数据，评估了阿拉瓜亚河中部在种群分化中的作用，并估计了各谱系之间的分化时间，以评估这些物种的分化时间。这6种袋鼬科有袋动物呈现出不同的种内遗传模式和结构。3种体型较大、适应性更强的物种，即白腹袋鼬、草原袋鼬和南美林负鼠，显示出跨越阿拉瓜亚河的连通性。相比之下，3种体型较小、较为特化的物种，即敏捷纤细负鼠、鼠形侏袋貂和德氏侏袋貂的遗传结构则受阿拉瓜亚河中部的影响。此外，后两种物种东西两岸种群的分化与阿拉瓜亚河沉积物形成的年代一致。我们推测，阿拉瓜亚河作为河流屏障的作用与这6种袋鼬科物种的生态特化程度及其跨越河流或通过相关栖息地类型扩散的能力差异有关。
