Initiation of speciation across multiple dimensions in a rock-restricted, tropical lizard

Population isolation and concomitant genetic divergence, resulting in strong phylogeographic structure, is a core aspect of speciation initiation. If and how speciation then proceeds and ultimately completes depends on multiple factors that mediate reproductive isolation, including divergence in genomes, ecology, and mating traits. Here we explored these multiple dimensions in two young (Plio-Pleistocene) species complexes of gekkonid lizards (Heteronotia) from the Kimberley–Victoria River regions of tropical Australia. Using mtDNA screening and exon capture phylogenomics, we show that the rock-restricted H. planiceps exhibits exceptional fine-scale phylogeographic structure compared to the co-distributed habitat generalist H. binoei. This indicates pervasive population isolation and persistence in the rock-specialist, and thus a high rate of speciation initiation across this geographically complex region, with levels of genomic divergence spanning the \"grey zone\" of speciation. Proxima...

种群隔离伴随遗传分化，进而形成显著的系统地理结构（phylogeographic structure），是物种形成起始阶段的核心特征。物种形成后续能否推进并最终完成，取决于诸多介导生殖隔离的因素，包括基因组分化、生态分化以及交配性状分化。本研究聚焦澳大利亚热带地区金伯利-维多利亚河区域的两个上新世-更新世时期形成的年轻壁虎科（Gekkonidae）异趾虎属（Heteronotia）物种复合体，对上述多维度过程展开探究。通过线粒体DNA（mtDNA）筛查与外显子捕获系统发育基因组学（exon capture phylogenomics）分析，本研究发现：专性栖息于岩石生境的平原异趾虎（H. planiceps）相较于同域分布的广适生境物种比诺异趾虎（H. binoei），展现出极高精细度的系统地理结构。这表明该岩石特化物种普遍存在种群隔离与存续状态，因此在这片地理环境复杂的区域内，物种形成起始频率较高，其基因组分化水平处于物种形成"灰色地带"区间。Proxima...