干旱生物群落在新热带地区尤其突出,提供了一些最具代表性的景观和大部分物种多样性。为了了解墨西哥沙漠谱系形成的一些进化过程,研究了Fouquieria的多样化,其中包括11种,都是北美温暖的沙漠和干燥的亚热带地区特有的。使用来自质体DNA序列的系统发育与来自Fouquieria中识别的所有物种种群的个体样本,我们估计发散时间,时间多样化异质性检验,地理结构测试,进行祖区重建。Fouquieria是一个古老的谱系,与Polemoniaceca分离。75.54毫安。Fouquieria的Mio-上新世多样化,与区域沙漠早期发育相关的新近纪造山作用得到了大力支持。对时间多样化异质性的检验表明,在其演化史上,Fouquieria在大约12.72Ma时发生了剧烈的多元化利率变化,同意假设,北美沙漠的一些谱系早在上新世晚期就多样化了,而不是在更新世。长期的多样化动态分析表明,灭绝在Fouquieria的进化中也发挥了重要作用,在过程开始时具有非常高的比率。从上世纪晚期开始,Fouquieria经历了实质性的多元化变化,涉及高物种形成减少到现在和可忽略不计的灭绝,这与这一时期稀少的化石记录是一致的。地理系统发育结构和居住在不同沙漠核中的大多数姐妹物种的模式支持,按距离进行隔离可能是物种形成的主要驱动力。
Arid biomes are particularly prominent in the
Neotropics providing some of its most emblematic landscapes and a substantial part of its species diversity. To understand some of the evolutionary processes underlying the speciation of lineages in the Mexican Deserts, the diversification of Fouquieria is investigated, which includes eleven species, all endemic to the warm deserts and dry subtropical regions of North America. Using a phylogeny from plastid DNA sequences with samples of individuals from populations of all the species recognized in Fouquieria, we estimate divergence times, test for temporal diversification heterogeneity, test for geographical structure, and conduct ancestral area reconstruction. Fouquieria is an ancient lineage that diverged from Polemoniaceae ca. 75.54 Ma. A Mio-Pliocene diversification of Fouquieria with vicariance, associated with Neogene orogenesis underlying the early development of regional deserts is strongly supported. Test for temporal diversification heterogeneity indicates that during its evolutionary history, Fouquieria had a drastic diversification rate shift at ca.12.72 Ma, agreeing with hypotheses that some of the lineages in North American deserts diversified as early as the late Miocene to Pliocene, and not during the Pleistocene. Long-term diversification dynamics analyses suggest that extinction also played a significant role in Fouquieria\'s evolution, with a very high rate at the onset of the process. From the late Miocene onwards, Fouquieria underwent substantial diversification change, involving high speciation decreasing to the present and negligible extinction, which is congruent with its scant fossil record during this period. Geographic phylogenetic structure and the pattern of most sister species inhabiting different desert nucleus support that isolation by distance could be the main driver of speciation.