Abstract:
Palaeontologists have long sought to explain the diversification of individual clades to whole biotas at global scales. Advances in our understanding of the spatial distribution of the fossil record through geological time, however, has demonstrated that global trends in biodiversity were a mosaic of regionally heterogeneous diversification processes. Drivers of diversification must presumably have also displayed regional variation to produce the spatial disparities observed in past taxonomic richness. Here, we analyse the fossil record of ammonoids, pelagic shelled cephalopods, through the Late Cretaceous, characterised by some palaeontologists as an interval of biotic decline prior to their total extinction at the Cretaceous-Paleogene boundary. We regionally subdivide this record to eliminate the impacts of spatial sampling biases and infer regional origination and extinction rates corrected for temporal sampling biases using Bayesian methods. We then model these rates using biotic and abiotic drivers commonly inferred to influence diversification. Ammonoid diversification dynamics and responses to this common set of diversity drivers were regionally heterogeneous, do not support ecological decline, and demonstrate that their global diversification signal is influenced by spatial disparities in sampling effort. These results call into question the feasibility of seeking drivers of diversity at global scales in the fossil record.
摘要:
古生物学家长期以来一直试图在全球范围内解释单个进化枝对整个生物的多样化。我们通过地质时间对化石记录的空间分布的理解的进展,然而,已经证明,生物多样性的全球趋势是区域异质性多样化进程的马赛克。多元化的驱动因素也必须显示出区域差异,以产生在过去的分类学丰富度中观察到的空间差异。这里,我们分析了类抗生素的化石记录,中上层带壳头足类动物,在白垩纪晚期,被一些古生物学家表征为在白垩纪-古近纪边界完全灭绝之前的生物衰退间隔。我们对该记录进行了区域细分,以消除空间采样偏差的影响,并使用贝叶斯方法推断针对时间采样偏差进行校正的区域起源和灭绝率。然后,我们使用通常推断影响多元化的生物和非生物驱动因素对这些比率进行建模。Ammonoid多样化动态和对这组共同的多样性驱动因素的响应在区域上是异质的,不支持生态衰退,并证明了他们的全球多样化信号受到抽样努力的空间差异的影响。这些结果质疑在化石记录中寻求全球范围内多样性驱动因素的可行性。