Phylogeny, Macroevolutionary Trends and Historical Biogeography of Sloths: Insights From a Bayesian Morphological Clock Analysis
Phylogeny, Macroevolutionary Trends and Historical Biogeography of Sloths: Insights From a Bayesian Morphological Clock Analysis
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DOI：
10.1093/sysbio/syy058
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发表时间：
2019-03-01
影响因子：
6.5
通讯作者：
Farina, Richard A.
中科院分区：
文献类型：
--
作者：
Varela, Luciano;Tambusso, P. Sebastian;Farina, Richard A.
树懒，像其他xenarthrans一样，是一个非常有趣的哺乳动物群体，在南美洲经过漫长的进化和多样化历史后，在加勒比海的岛屿上建立起来，后来在大美洲生物交流期间到达北美。在这三个地区，它们都是令人印象深刻的更新世巨型动物群的一部分。大多数分类群灭绝了，只有两个小的，远亲的树居属幸存下来。在这里，我们将几个最近描述的属树懒到一个组装的形态数据超矩阵和贝叶斯推理，使用系统发育和形态时钟的方法，64树懒属。因此，我们调查的不同谱系的分歧和他们的多样性，形态差异和地理历史的时间方面的组的演变。所获得的系统发育支持了该类群普遍公认的分支的存在。我们的研究结果提供了分歧的时间估计Folivora内的主要分支，不能与分子方法。谱系多样性显示了早期的增加，在中新世早期达到高峰，随后在Santacrucian（中新世早期）结束时出现大幅下降。晚中新世的第二个高峰之后，在Huayquerian（晚中新世）结束时也出现了一次大的下降。这两项活动对家庭的影响不同。在此之后，上新世-更新世出现了一个轻微的下降，然后在更新世末灭绝时出现了明显的下降。表型进化率很高，在早期的历史的分支，主要与Mylodontidae，但迅速下降到较低的值约25马，而Megalonychidae有较低的利率在开始之后的稳定增加，在晚中新世和上新世达到高峰。形态差异表现出类似的趋势，早期增加，然后缓慢增加的阶段，通过晚渐新世和早中新世，并结束与另一个增加开始于中新世中期。生物地理分析表明，南美洲南部的分支的起源和早期多样化事件发生的主要地区最有可能的地区。Mephiinae和Nothrotheriinae的基底节点与安第斯山脉的隆起事件密切相关，而Mylodontidae的早期历史与南美洲南部密切相关，也显示了早期占领的北方地区。在巨爪科中，我们的结果表明Choloepus是岛屿分散祖先的后代，并且可能是起源于中美洲或北美的分支重新入侵南美洲的。
Sloths, like other xenarthrans, are an extremely interesting group of mammals that, after a long history of evolution and diversification in South America, became established on islands in the Caribbean and later reached North America during the Great American Biotic Interchange. In all three regions, they were part of the impressive Pleistocene megafauna. Most taxa became extinct and only two small, distantly related tree-dwelling genera survived. Here, we incorporate several recently described genera of sloths into an assembled morphological data supermatrix and apply Bayesian inference, using phylogenetic and morphological clock methods, to 64 sloth genera. Thus, we investigate the evolution of the group in terms of the timing of divergence of different lineages and their diversity, morphological disparity and biogeographical history. The phylogeny obtained supports the existence of the commonly recognized clades for the group. Our results provide divergence time estimates for the major clades within Folivora that could not be dated with molecular methods. Lineage diversity shows an early increase, reaching a peak in the Early Miocene followed by a major drop at the end of the Santacrucian (Early Miocene). A second peak in the Late Miocene was also followed by a major drop at the end of the Huayquerian (Late Miocene). Both events show differential impact at the family level. After that, a slight Plio-Pleistocene decline was observed before the marked drop with the extinction at the end of the Pleistocene. Phenotypic evolutionary rates were high during the early history of the clade, mainly associated with Mylodontidae, but rapidly decreased to lower values around 25 Ma, whereas Megalonychidae had lower rates at the beginning followed by a steady increase, peaking during the Late Miocene and the Pliocene. Morphological disparity showed a similar trend, with an early increase, followed by a slowly increasing phase through the Late Oligocene and Early Miocene, and ending with another increase beginning at the middle of the Miocene. Biogeographic analysis showed southern South America as the most probable area of origin of the clade and the main region in which the early diversification events took place. Both Megatheriinae and Nothrotheriinae basal nodes were strongly correlated with Andean uplift events, whereas the early history of Mylodontidae is closely associated with southern South America and also shows an early occupation of the northern regions. Within Megalonychidae, our results show Choloepus as a descendant of an island dispersing ancestor and a probable re-ingression to South America by a clade that originated in Central or North America.