Tempo and Mode of Diversification of Lake Tanganyika Cichlid Fishes
Tempo and Mode of Diversification of Lake Tanganyika Cichlid Fishes
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DOI：
10.1371/journal.pone.0001730
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发表时间：
2008-03-05
期刊：
影响因子：
3.7
通讯作者：
Barraclough, Timothy G.
中科院分区：
文献类型：
--
作者：
Day, Julia J.;Cotton, James A.;Barraclough, Timothy G.
背景资料：了解物种多样性在分类群体和地区之间差异的原因是进化生物学的一个基本目标。解决这些问题是困难的，因为需要密集采样的adaptogenies和合适的经验systems.Methodology/主要研究结果：在这里，我们调查的慈鲷鱼辐射坦噶尼喀湖，并表明，每个谱系多样化率已超过6倍慢于在物种群的湖泊维多利亚和马拉维。即使在坦噶尼喀湖多样化的高峰期，该结果也成立，排除了湖泊年龄作为平均速率缓慢的解释，并且对地质时期慈鲷辐射校准的不确定性具有鲁棒性。此外，坦噶尼喀湖血统，无论不同的生物特征（e。G.性二色分支与性单色分支）以类似的速度多样化，在一系列植物和动物分支中属于典型的估计。例如，大多数性二色haplochromines，这已形成爆炸性的维多利亚湖和马拉维，显示在坦噶尼喀湖（在那里他们被称为Tropheini）适度的利率。结论/意义：我们的研究结果表明，无论是坦噶尼喀湖的环境是不太有利于慈鲷鱼物种或显着的多样化能力的haplochromines被抑制由以前占用的老辐射。虽然结果表明，在塑造慈鲷多样化的环境中起主导作用，在Tanganyikan部落之间的多样化的时间差异表明，生物学差异仍然是重要的动态的物种建立在湖中。虽然我们不能解决的辐射相对于湖泊的起源，因为缺乏强大的地质日期校准慈鲷，我们的研究结果是一致的情况下，不同的分支反映独立的适应性辐射到不同的广泛的生态位在湖中。
Background: Understanding the causes of disparities in species diversity across taxonomic groups and regions is a fundamental aim in evolutionary biology. Addressing these questions is difficult because of the need for densely sampled phylogenies and suitable empirical systems.Methodology/Principal Findings: Here we investigate the cichlid fish radiation of Lake Tanganyika and show that per lineage diversification rates have been more than six times slower than in the species flocks of Lakes Victoria and Malawi. The result holds even at peak periods of diversification in Lake Tanganyika, ruling out the age of the lake as an explanation for slow average rates, and is robust to uncertainties over the calibration of cichlid radiations in geological time. Moreover, Lake Tanganyika lineages, irrespective of different biological characteristics ( e. g. sexually dichromatic versus sexually monochromatic clades), have diversified at similar rates, falling within typical estimates across a range of plant and animal clades. For example, the mostly sexually dichromatic haplochromines, which have speciated explosively in Lakes Victoria and Malawi, have displayed modest rates in Lake Tanganyika ( where they are called Tropheini).Conclusion/Significance: Our results show that either the Lake Tanganyika environment is less conducive for cichlid speciation or the remarkable diversifying abilities of the haplochromines were inhibited by the prior occupancy of older radiations. Although the results indicate a dominant role for the environment in shaping cichlid diversification, differences in the timing of diversification among the Tanganyikan tribes indicate that biological differences were still important for the dynamics of species build-up in the lake. While we cannot resolve the timing of the radiation relative to the origin of the lake, because of the lack of robust geological date calibrations for cichlids, our results are consistent with a scenario that the different clades reflect independent adaptive radiations into different broad niches in the lake.