Warren Ben H, Bermingham Eldredge, Bowie Rauri C K, Prys-Jones Robert P, Thébaud Christophe
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Mol Phylogenet Evol. 2003 Oct;29(1):67-85. doi: 10.1016/s1055-7903(03)00063-0.
We constructed a phylogenetic hypothesis for western Indian Ocean sunbirds (Nectarinia) and used this to investigate the geographic pattern of their diversification among the islands of the Indian Ocean. A total of 1309 bp of mitochondrial sequence data was collected from the island sunbird taxa of the western Indian Ocean region, combined with sequence data from a selection of continental (African and Asian) sunbirds. Topological and branch length information combined with estimated divergence times are used to present hypotheses for the direction and sequence of colonization events in relation to the geological history of the Indian Ocean region. Indian Ocean sunbirds fall into two well-supported clades, consistent with two independent colonizations from Africa within the last 3.9 million years. The first clade contains island populations representing the species Nectarinia notata, while the second includes Nectarinia souimanga, Nectarinia humbloti, Nectarinia dussumieri, and Nectarinia coquereli. With respect to the latter clade, application of Bremer's [Syst. Biol. 41 (1992) 436] ancestral areas method permits us to posit the Comoros archipelago as the point of initial colonization in the Indian Ocean. The subsequent expansion of the souimanga clade across its Indian Ocean range occurred rapidly, with descendants of this early expansion remaining on the Comoros and granitic Seychelles. The data suggest that a more recent expansion from Anjouan in the Comoros group led to the colonization of Madagascar by sunbirds representing the souimanga clade. In concordance with the very young geological age of the Aldabra group, the sunbirds of this archipelago have diverged little from the Madagascar population; this is attributed to colonization of the Aldabra archipelago in recent times, in one or possibly two or more waves originating from Madagascar. The overall pattern of sunbird radiation across Indian Ocean islands indicates that these birds disperse across ocean barriers with relative ease, but that their subsequent evolutionary success probably depends on a variety of factors including prior island occupation by competing species.
我们构建了西印度洋太阳鸟（花蜜鸟属）的系统发育假说，并以此研究它们在印度洋各岛屿间多样化的地理模式。从西印度洋地区的岛屿太阳鸟分类群中收集了总共1309个碱基对的线粒体序列数据，并结合了一些大陆（非洲和亚洲）太阳鸟的序列数据。拓扑结构和分支长度信息以及估计的分歧时间被用于提出与印度洋地区地质历史相关的殖民事件方向和顺序的假说。印度洋太阳鸟分为两个得到充分支持的进化枝，这与过去390万年中从非洲的两次独立殖民相一致。第一个进化枝包含代表黑颏花蜜鸟物种的岛屿种群，而第二个进化枝包括紫颊花蜜鸟、亨氏花蜜鸟、杜氏花蜜鸟和科氏花蜜鸟。对于后一个进化枝，应用布雷默的[《系统生物学》41（1992）436]祖先区域方法使我们能够假定科摩罗群岛是印度洋最初的殖民点。紫颊花蜜鸟进化枝随后在其印度洋分布范围内迅速扩张，这次早期扩张的后代留在了科摩罗和花岗岩质的塞舌尔群岛。数据表明，最近从科摩罗群岛中的昂儒昂岛扩张导致了代表紫颊花蜜鸟进化枝的太阳鸟对马达加斯加的殖民。与阿尔达布拉群岛非常年轻的地质年代一致，该群岛的太阳鸟与马达加斯加种群的差异很小；这归因于阿尔达布拉群岛最近的殖民，其源于马达加斯加的一波或可能两波或更多波次。太阳鸟在印度洋岛屿上辐射的总体模式表明，这些鸟类相对容易地跨越海洋屏障扩散，但它们随后的进化成功可能取决于多种因素，包括竞争物种先前对岛屿的占据情况。
