Chapple David G, Keogh J Scott, Hutchinson Mark N
School of Botany and Zoology, Australian National University, Canberra ACT 0200, Australia.
Mol Phylogenet Evol. 2004 Dec;33(3):549-61. doi: 10.1016/j.ympev.2004.08.010.
We assembled a molecular phylogeny for the arid-zone members of the Egernia whitii species group to test Pianka's [Zoogeography and speciation of Australian desert lizards: an ecological perspective, Copeia (1972) 127-145] hypothesis that habitat specificity to the three major arid-zone vegetation communities is the primary cause of lizard speciation within the arid interior of Australia. This hypothesis predicts that species should exhibit phylogeographic structuring concordant with the major arid-zone vegetation types. Sequence data were obtained from four of the five arid-zone members of the E. whitii species group, and from across the ranges of the ecologically generalized E. inornata and E. multiscutata and the more specialized E. striata. We targeted a fragment (696 base pair (bp)) of the mitochondrial genome comprising the 3' half of the ND4 gene. We analysed the data using parsimony, maximum likelihood and Bayesian methods. Our phylogeny confirms the monophyly of the arid-zone members of the species group, although the phylogenetic relationships among species were not fully resolved. Although our topology does not support the recognition of the existing subspecies within E. multiscutata, there is a substantial phylogeographic break between South Australian/Victorian (Clade 1) and Western Australian (Clade 2) populations. We found considerable phylogeographic structure within E. inornata, with six major clades identified. However, these clades were not concordant with the distribution of habitat types in the arid-zone. Phylogeographic structure was also observed in the more specialized E. striata, although our analysis revealed close phylogenetic affinities between the sympatric species E. striata and E. kintorei. Shimodaira-Hasegawa topology tests were equivocal in regard to whether the phylogeographic structure within E. striata was in accordance with Pianka's predictions. Although our data failed to provide strong support for the suggestion that ecological and habitat factors are responsible for the diversification of arid-zone lizards, most E. inornata and E. striata populations had similar habitats, indicating that adaptation to particular habitats may have some role in the speciation of lizards in the Australian arid-zone.
我们构建了惠氏石龙子（Egernia whitii）物种组干旱区成员的分子系统发育树，以检验 Pianka [《澳大利亚沙漠蜥蜴的动物地理学与物种形成：生态学视角》，《科普伊亚》（1972 年）第 127 - 145 页] 的假说，即对干旱区三大主要植被群落的栖息地特异性是澳大利亚干旱内陆蜥蜴物种形成的主要原因。该假说预测，物种应表现出与主要干旱区植被类型一致的系统地理学结构。序列数据取自惠氏石龙子物种组五个干旱区成员中的四个，以及生态分布广泛的无饰石龙子（E. inornata）、多鳞石龙子（E. multiscutata）和更具特异性的条纹石龙子（E. striata）的分布范围。我们选取了线粒体基因组的一个片段（696 个碱基对（bp）），该片段包含 ND4 基因的 3' 端一半。我们使用简约法、最大似然法和贝叶斯方法分析数据。我们的系统发育树证实了该物种组干旱区成员的单系性，尽管物种间的系统发育关系并未完全解析清楚。虽然我们的拓扑结构不支持对多鳞石龙子现有亚种的划分，但南澳大利亚/维多利亚（分支 1）和西澳大利亚（分支 2）种群之间存在显著的系统地理学间断。我们在无饰石龙子中发现了相当明显的系统地理学结构，识别出了六个主要分支。然而，这些分支与干旱区栖息地类型的分布并不一致。在更具特异性的条纹石龙子中也观察到了系统地理学结构，尽管我们的分析揭示了同域分布的条纹石龙子和金托雷石龙子（E. kintorei）之间存在密切的系统发育亲缘关系。关于条纹石龙子的系统地理学结构是否符合 Pianka 的预测，Shimodaira - Hasegawa 拓扑检验结果并不明确。虽然我们的数据未能为生态和栖息地因素导致干旱区蜥蜴多样化这一观点提供有力支持，但大多数无饰石龙子和条纹石龙子种群具有相似的栖息地，这表明对特定栖息地的适应可能在澳大利亚干旱区蜥蜴的物种形成中起到了一定作用。
