THE EARLY DIVERSIFICATION HISTORY OF DIDELPHID MARSUPIALS: A WINDOW INTO SOUTH AMERICA'S "SPLENDID ISOLATION"
THE EARLY DIVERSIFICATION HISTORY OF DIDELPHID MARSUPIALS: A WINDOW INTO SOUTH AMERICA'S "SPLENDID ISOLATION"
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DOI：
10.1111/evo.12290
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发表时间：
2014-03-01
期刊：
影响因子：
3.3
通讯作者：
Voss, Robert S.
中科院分区：
文献类型：
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作者：
Jansa, Sharon A.;Barker, F. Keith;Voss, Robert S.
南美哺乳动物的地质记录在空间上是有偏见的，因为多产的化石地点集中在高纬度。因此，亚马逊和其他热带生物群中哺乳动物多样化的历史在很大程度上是未知的。在这里，我们报告了基于时间校准的负鼠(Didelphidae)的分子系统学的多样性分析，Didelphidae是一个物种丰富的支系，主要是热带有袋类动物，来自于晚渐新世的共同祖先。对该系统发育的生境和地理位置的优化表明：(1)南美洲潮湿的森林中生活着基本的双翅目动物谱系；(2)直到中新世晚期，干森林生境中的双翅目动物才发生多样化；(3)大多数双翅目动物谱系直到上新世才进入北美。我们还总结了早中新世大灭绝事件的证据，并讨论了不同的原因解释。据我们所知，这项研究提供了第一个发表的任何动物支系大规模灭绝的分子系统学证据，这也是第一次对这种事件的证据(在任何植物或动物分类群中)进行了统计学意义的测试。从对其他共生哺乳动物群体的多样性分析中，可能会得到一些可能的证伪观察，这些观察结果可能有助于区分提出的双翅目动物大规模灭绝的其他解释。
The geological record of South American mammals is spatially biased because productive fossil sites are concentrated at high latitudes. As a result, the history of mammalian diversification in Amazonia and other tropical biomes is largely unknown. Here we report diversification analyses based on a time-calibrated molecular phylogeny of opossums (Didelphidae), a species-rich clade of mostly tropical marsupials descended from a Late Oligocene common ancestor. Optimizations of habitat and geography on this phylogeny suggest that (1) basal didelphid lineages inhabited South American moist forests; (2) didelphids did not diversify in dry-forest habitats until the Late Miocene; and (3) most didelphid lineages did not enter North America until the Pliocene. We also summarize evidence for an Early- to Middle-Miocene mass extinction event, for which alternative causal explanations are discussed. To the best of our knowledge, this study provides the first published molecular-phylogenetic evidence for mass extinction in any animal clade, and it is the first time that evidence for such an event (in any plant or animal taxon) has been tested for statistical significance. Potentially falsifying observations that could help discriminate between the proposed alternative explanations for didelphid mass extinction may be obtainable from diversification analyses of other sympatric mammalian groups.