Division of Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australia.
Department of Biological Sciences, Macquarie University, Sydney, Australia.
Mol Phylogenet Evol. 2014 Feb;71:149-56. doi: 10.1016/j.ympev.2013.11.012. Epub 2013 Dec 6.
Jacky dragons (Amphibolurus muricatus) are ubiquitous in south-eastern Australia and were one of the first Australian reptiles to be formally described. Because they are so common, Jacky dragons are widely used as a model system for research in evolutionary biology and ecology. In addition, their distribution along the Great Dividing Range of eastern Australia provides an opportunity to examine the influence of past biogeographical processes, particularly the expansion and contraction of forest habitats, on the diversification of this iconic agamid lizard. We generated sequence data for two mitochondrial and three nuclear DNA loci (4251base pairs) for 62 Jacky dragons sampled from throughout their distribution. Phylogenetic analyses based on maximum likelihood and Bayesian species-tree methods revealed five geographically structured clades separated by up to 6% mitochondrial and 0.7% nuclear sequence divergence. We also quantified body proportion variation within and between these genetic clades for more than 500 specimens and found no evidence of any significant differentiation in body proportions across their range. Based on body proportion homogeneity and lack of resolution in the nuclear loci, we do not support taxonomic recognition of any of the mitochondrial clades. Instead, A. muricatus is best thought of as a single species with phylogeographic structure. The genetic patterns observed in the Jacky dragon are consistent with fragmented populations reduced to multiple refugia during cold, arid phases when forested habitats were greatly restricted. Consequently, the inferred biogeographic barriers for this taxon appear to be in line with lowland breaks in the mountain ranges. Our results are congruent with studies of other reptiles, frogs, mammals, birds and invertebrates, and together highlight the overarching effects of widespread climatic and habitat fluctuations along the Great Dividing Range since the Pliocene.
杰克森蜥蜴（Amphibolurus muricatus）广泛分布于澳大利亚东南部，是最早被正式描述的澳大利亚爬行动物之一。由于它们非常常见，因此杰克森蜥蜴被广泛用作进化生物学和生态学研究的模型系统。此外，它们在澳大利亚东部大分水岭的分布为研究过去生物地理过程（特别是森林栖息地的扩张和收缩）对这种标志性蜥蜴的多样化的影响提供了机会。我们从分布范围内采集了 62 只杰克森蜥蜴，为它们的两个线粒体和三个核 DNA 基因座（4251 个碱基对）生成了序列数据。基于最大似然和贝叶斯种系发生方法的系统发育分析揭示了五个地理结构的分支，它们之间的线粒体和核序列差异最大可达 6%和 0.7%。我们还对这些遗传分支内和之间的 500 多个样本的身体比例变化进行了量化，结果表明在其分布范围内，身体比例没有任何明显的分化。基于身体比例的同质性和核基因座缺乏分辨率，我们不支持对任何线粒体分支进行分类学识别。相反，A. muricatus 最好被视为一个具有地理结构的单一物种。在杰克森蜥蜴中观察到的遗传模式与在寒冷、干旱时期森林栖息地大大受限而使种群碎片化并减少到多个避难所的情况一致。因此，推断该分类单元的生物地理屏障似乎与山脉中的低地断裂相一致。我们的研究结果与其他爬行动物、青蛙、哺乳动物、鸟类和无脊椎动物的研究结果一致，共同强调了上新世以来大分水岭地区广泛的气候和栖息地波动的总体影响。
