School of Life Sciences, University of Nevada, Las Vegas, NV 89154-4004, USA.
Mol Phylogenet Evol. 2012 Jan;62(1):87-96. doi: 10.1016/j.ympev.2011.09.007. Epub 2011 Sep 22.
The widespread montane Mexican horned lizard Phrynosoma orbiculare (Squamata: Phrynosomatidae) represents an ideal species to investigate the relative impacts of Neogene vicariance and Quaternary climate change on lineage diversification across the Mexican highlands. We used mitochondrial DNA to examine the maternal history of P. orbiculare and estimate the timing and tempo of lineage diversification. Based on our results, we inferred 11 geographically structured, well supported mitochondrial lineages within this species, suggesting P. orbiculare represents a species complex. Six divergences between lineages likely occurred during the Late Miocene and Pliocene, and four splits probably happened during the Pleistocene. Diversification rate appeared relatively constant through time. Spatial and temporal divergences between lineages of P. orbiculare and co-distributed taxa suggest that a distinct period of uplifting of the Transvolcanic Belt around 7.5-3 million years ago broadly impacted diversification in taxa associated with this mountain range. To the north, several river drainages acting as filter barriers differentially subdivided co-distributed highland taxa through time. Diversification patterns observed in P. orbiculare provide additional insight into the mechanisms that impacted differentiation of highland taxa across the complex Mexican highlands.
广泛分布于墨西哥山地的角蟾 Phrynosoma orbiculare（有鳞目：角蟾科）是研究中新世地理隔离和第四纪气候变化对墨西哥高地谱系多样化相对影响的理想物种。我们使用线粒体 DNA 来研究 P. orbiculare 的母系历史，并估计谱系多样化的时间和速度。根据我们的研究结果，我们推断出该物种存在 11 个地理结构良好、支持度高的线粒体谱系，表明 P. orbiculare 是一个物种复合体。6 次谱系分歧可能发生在中新世晚期和上新世，4 次分裂可能发生在更新世。多样化速度似乎随时间相对稳定。P. orbiculare 与共分布种之间的谱系在空间和时间上的分歧表明，约 750-300 万年前，火山带的抬升导致了与该山脉相关的分类群的广泛多样化。在北部，随着时间的推移，几条河流流域作为过滤屏障，使共分布的高地分类群发生了不同程度的细分。在 P. orbiculare 中观察到的多样化模式为理解影响复杂的墨西哥高地高地分类群分化的机制提供了更多的见解。
