Glor Richard E, Losos Jonathan B, Larson Allan
Department of Biology, Campus Box 1137, Washington University, St. Louis, MO 63130-4899, USA.
Mol Ecol. 2005 Jul;14(8):2419-32. doi: 10.1111/j.1365-294X.2005.02550.x.
Overwater dispersal and subsequent allopatric speciation contribute importantly to the species diversity of West Indian Anolis lizards and many other island radiations. Here we use molecular phylogenetic analyses to assess the contribution of overwater dispersal to diversification of the Anolis carolinensis subgroup, a clade comprising nine canopy-dwelling species distributed across the northern Caribbean. Although this clade includes some of the most successful dispersers and colonists in the anole radiation, the taxonomic status and origin of many endemic populations have been ambiguous. New mitochondrial and nuclear DNA sequences from four species occurring on small islands or island banks (Anolis brunneus, Anolis longiceps, Anolis maynardi, Anolis smaragdinus) and one species from the continental United States (A. carolinensis) are presented and analysed with homologous sequences sampled from related species on Cuba (Anolis allisoni and Anolis porcatus). Our analyses confirm that all five non-Cuban species included in our study represent distinct, independently evolving lineages that warrant continued species recognition. Moreover, our results support Ernest Williams's hypothesis that all of these species originated by overseas colonization from Cuban source populations. However, contrary to Williams's hypothesis of Pleistocene dispersal, most colonization events leading to speciation apparently occurred earlier, in the late Miocene-Pliocene. These patterns suggest that overwater dispersal among geologically distinct islands and island banks is relatively infrequent in anoles and has contributed to allopatric speciation. Finally, our results suggest that large Greater Antillean islands serve as centres of origin for regional species diversity.
水上扩散及随后的异域物种形成对西印度安乐蜥及许多其他岛屿辐射物种的物种多样性有着重要贡献。在此，我们运用分子系统发育分析来评估水上扩散对卡罗来纳安乐蜥亚组多样化的贡献，该亚组包含分布于加勒比海北部的9种树栖物种。尽管这个亚组包含了安乐蜥辐射中一些最成功的扩散者和殖民者，但许多特有种群的分类地位和起源一直不明确。我们展示了来自小岛屿或岛滩上的4个物种（棕色安乐蜥、长头安乐蜥、马氏安乐蜥、翡翠安乐蜥）以及来自美国大陆的1个物种（卡罗来纳安乐蜥）的新线粒体和核DNA序列，并与从古巴相关物种（艾氏安乐蜥和猪鼻安乐蜥）中采样的同源序列进行了分析。我们的分析证实，我们研究中包含的所有5个非古巴物种均代表不同的、独立进化的谱系，值得继续作为独立物种来识别。此外，我们的结果支持欧内斯特·威廉姆斯的假说，即所有这些物种都起源于来自古巴源种群的海外殖民。然而，与威廉姆斯关于更新世扩散的假说相反，导致物种形成的大多数殖民事件显然发生得更早，是在中新世晚期至上新世。这些模式表明，在地质上不同的岛屿和岛滩之间的水上扩散在安乐蜥中相对不常见，并促成了异域物种形成。最后，我们的结果表明，大安的列斯群岛大岛是区域物种多样性的起源中心。
