Data from: Morphological clocks in palaeontology, and a mid-Cretaceous origin of crown Aves

The limited fossil evidence for modern (crown) birds during the Cretaceous is consistent with a recent (Palaeogene) radiation; however, molecular clock studies have consistently suggested that modern birds radiated deep in the Mesozoic, with the paucity of fossils prior to the latest Cretaceous explainable by preservational bias. This issue is here addressed using Bayesian methods which integrate stratigraphical and morphological data to simultaneously infer evolutionary relationships and divergence times. These analyses place the diversification of modern birds in the mid-Cretaceous (~100-110Ma), only slightly more recent than many genetic studies, and congruent with latest molecular estimates.

白垩纪时期现代冠群鸟类（crown birds）的化石证据十分有限，这与现代鸟类辐射发生于古近纪的假说相一致；然而，分子钟研究始终表明现代鸟类的辐射起源于中生代深部，晚白垩世末期之前的化石稀缺可归因于保存偏差。针对这一问题，本研究采用整合了地层数据与形态学数据的贝叶斯方法（Bayesian methods），同时推断演化关系与分化时间。分析结果显示，现代鸟类的类群多样化发生在白垩纪中期（约100-110百万年前），仅比多数遗传学研究的估算结果稍晚，且与最新的分子学估算结果一致。