A timescale for placental mammal diversification based on Bayesian modeling of the fossil record
A timescale for placental mammal diversification based on Bayesian modeling of the fossil record
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DOI：
10.1016/j.cub.2023.06.016
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发表时间：
2023-06
期刊：
影响因子：
9.2
通讯作者：
Emily M. Carlisle;C. Janis;D. Pisani;P. Donoghue;D. Silvestro
中科院分区：
文献类型：
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作者：
Emily M. Carlisle;C. Janis;D. Pisani;P. Donoghue;D. Silvestro
胎盘哺乳动物辐射的时间一直是争论的焦点，争论的焦点是建立进化时间尺度的竞争方法的有效性。分子钟分析估计，胎盘哺乳动物起源于晚白垩世至侏罗纪的白垩纪-古近纪（K-Pg）大灭绝之前。然而，没有确定的化石胎盘之前的K-Pg边界是兼容的后白垩纪的起源。尽管如此，血统分歧必须在它在后代血统中表现出表型之前发生。这一点，再加上岩石和化石记录的不均匀性，要求对化石记录进行解释，而不是字面意思。为了实现这一目标，我们引入了一个扩展的贝叶斯布朗桥模型，估计起源的年龄，并在适用的情况下，灭绝通过概率解释的化石记录。该模型估计胎盘的起源在晚白垩世，有序冠组起源于K-Pg边界或之后。结果减少了合理的间隔胎盘哺乳动物起源的分子钟估计的年轻范围。我们的研究结果支持了胎盘哺乳动物多样化的长爆炸和软爆炸模型，表明胎盘起源于K-Pg大灭绝之前不久。许多现代哺乳动物谱系的起源与K-Pg大灭绝重叠并遵循K-Pg大灭绝。
The timing of the placental mammal radiation has been the focus of debate over the efficacy of competing methods for establishing evolutionary timescales. Molecular clock analyses estimate that placental mammals originated before the Cretaceous-Paleogene (K-Pg) mass extinction, anywhere from the Late Cretaceous to the Jurassic. However, the absence of definitive fossils of placentals before the K-Pg boundary is compatible with a post-Cretaceous origin. Nevertheless, lineage divergence must occur before it can be manifest phenotypically in descendent lineages. This, combined with the non-uniformity of the rock and fossil records, requires the fossil record to be interpreted rather than read literally. To achieve this, we introduce an extended Bayesian Brownian bridge model that estimates the age of origination and, where applicable, extinction through a probabilistic interpretation of the fossil record. The model estimates the origination of placentals in the Late Cretaceous, with ordinal crown groups originating at or after the K-Pg boundary. The results reduce the plausible interval for placental mammal origination to the younger range of molecular clock estimates. Our findings support both the Long Fuse and Soft Explosive models of placental mammal diversification, indicating that the placentals originated shortly prior to the K-Pg mass extinction. The origination of many modern mammal lineages overlapped with and followed the K-Pg mass extinction.