Dinosaur diversity and the rock record
Dinosaur diversity and the rock record
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DOI：
10.1098/rspb.2009.0352
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发表时间：
2009-07-22
影响因子：
4.7
通讯作者：
Page, Victoria
中科院分区：
文献类型：
--
作者：
Barrett, Paul M.;McGowan, Alistair J.;Page, Victoria
古生物多样性分析支持宏观进化研究，允许识别大规模灭绝和适应性辐射。然而，最近对海洋无脊椎动物的大规模研究表明，地质因素在塑造多样性曲线的形状方面发挥着核心作用，并意味着这种曲线的许多特征代表了抽样人工制品，而不是真正的进化事件。为了测试类似的偏见是否会影响陆地类群的多样性估计，我们编制了三个中生代恐龙分支（鸟臀目，蜥脚目和兽脚目）的属丰富度估计。预期属丰富度的线性模型，构建了每个分支，通过时间作为一个代理的数量的含磷岩石露头的含磷地层的数量。然后将模拟的多样性估计值与观察到的模式进行比较。强有力的统计稳健的相关性表明，几乎所有方面的鸟臀目和兽脚类动物多样性曲线可以解释的地质megabiases，而sauropodomorph记录偏离模型预测，并可能是一个更强的竞争者，用于识别进化信号。与最近的其他研究相比，我们发现在白垩纪的最后阶段，恐龙属的丰富度显着下降，这表明在非鸟类恐龙最终灭绝之前，在白垩纪-古新世边界，该分支的多样性下降了几百万年。
Palaeobiodiversity analysis underpins macroevolutionary investigations, allowing identification of mass extinctions and adaptive radiations. However, recent large-scale studies on marine invertebrates indicate that geological factors play a central role in moulding the shape of diversity curves and imply that many features of such curves represent sampling artefacts, rather than genuine evolutionary events. In order to test whether similar biases affect diversity estimates for terrestrial taxa, we compiled genus-richness estimates for three Mesozoic dinosaur clades (Ornithischia, Sauropodomorpha and Theropoda). Linear models of expected genus richness were constructed for each clade, using the number of dinosaur-bearing formations available through time as a proxy for the amount of fossiliferous rock outcrop. Modelled diversity estimates were then compared with observed patterns. Strong statistically robust correlations demonstrate that almost all aspects of ornithischian and theropod diversity curves can be explained by geological megabiases, whereas the sauropodomorph record diverges from modelled predictions and may be a stronger contender for identifying evolutionary signals. In contrast to other recent studies, we identify a marked decline in dinosaur genus richness during the closing stages of the Cretaceous Period, indicating that the clade decreased in diversity for several million years prior to the final extinction of non-avian dinosaurs at the Cretaceous-Palaeocene boundary.