Deakin William J, Anderson Philip S L, den Boer Wendy, Smith Thomas J, Hill Jennifer J, Rücklin Martin, Donoghue Philip C J, Rayfield Emily J
School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK.
Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL, USA.
Sci Adv. 2022 Mar 18;8(11):eabl3644. doi: 10.1126/sciadv.abl3644.
The Siluro-Devonian adaptive radiation of jawed vertebrates, which underpins almost all living vertebrate biodiversity, is characterized by the evolutionary innovation of the lower jaw. Multiple lines of evidence have suggested that the jaw evolved from a rostral gill arch, but when the jaw took on a feeding function remains unclear. We quantified the variety of form in the earliest jaws in the fossil record from which we generated a theoretical morphospace that we then tested for functional optimality. By drawing comparisons with the real jaw data and reconstructed jaw morphologies from phylogenetically inferred ancestors, our results show that the earliest jaw shapes were optimized for fast closure and stress resistance, inferring a predatory feeding function. Jaw shapes became less optimal for these functions during the later radiation of jawed vertebrates. Thus, the evolution of jaw morphology has continually explored previously unoccupied morphospace and accumulated disparity through time, laying the foundation for diverse feeding strategies and the success of jawed vertebrates.
有颌脊椎动物在泥盆纪的适应性辐射奠定了几乎所有现存脊椎动物生物多样性的基础，其特征是下颌的进化创新。多条证据表明，颌是从吻部鳃弓进化而来的，但颌何时开始具有进食功能仍不清楚。我们对化石记录中最早的颌骨形态多样性进行了量化，由此生成了一个理论形态空间，然后对其进行功能最优性测试。通过与实际颌骨数据以及从系统发育推断的祖先重建的颌骨形态进行比较，我们的结果表明，最早的颌骨形状在快速闭合和抗应力方面是最优的，这意味着其具有捕食性进食功能。在有颌脊椎动物后来的辐射过程中，颌骨形状在这些功能方面变得不那么优化。因此，颌骨形态的进化不断探索以前未被占据的形态空间，并随着时间的推移积累了差异，为多样化的进食策略和有颌脊椎动物的成功奠定了基础。
