Both the evolution of tooth morphology and the relationship between dental features and diet in toothed birds have long been studied. Here we quantify variation in tooth crown shape in 28 key Mesozoic bird species, and examine differences in dental morphology among birds belonging to different taxonomic groupings and inferred to have had different diets. Using geometric morphometric methods (GMM) and phylogenetic comparative methods (PCM), we found few clear differences in tooth crown shape between different taxonomic and ecological categories, and our analysis provides little support for many dietary inferences drawn in previous studies. However, the Solnhofen Archaeopteryx, Jeholornis, Protopteryx, Pengornis, Longipteryx, Tianyuornis, Mengciusornis, Ichthyornis and Hesperornis all were found to possess relatively specialized tooth crown shapes, perhaps reflecting specialized diets such as insectivory, granivory, piscivory and consumption of soft-shelled arthropods. Similarity in tooth crown shape across many Mesozoic birds may indicate the lack of dietary specialization, and the association between tooth form and diet may have been weakened in any case by ‘functional replacement’ of the dentition by a horny beak and, in many cases, gastroliths.

长期以来，人们一直在研究牙齿形态的演变以及牙齿特征与饮食之间的关系。在这里，我们量化了 28 种关键中生代鸟类的牙冠形状的变化，并检查了属于不同分类群并推断具有不同饮食的鸟类牙齿形态的差异。使用几何形态测量方法 (GMM) 和系统发育比较方法 (PCM)，我们发现不同分类学和生态学类别之间的牙冠形状几乎没有明显差异，我们的分析对先前研究中得出的许多饮食推断几乎没有支持。然而，Solnhofen始祖鸟、Jeholornis、Protopteryx、Pengornis、Longipteryx、Tianyuornis、Mengciusornis、Ichthyornis和Hesperornis都被发现具有相对特殊的牙冠形状，这可能反映了特殊的饮食，如食虫类、食肉类、食鱼类和食用软壳节肢动物。许多中生代鸟类的牙冠形状相似可能表明缺乏饮食专门化，并且牙齿形状和饮食之间的关联在任何情况下都可能因角质喙对牙列的“功能性替代”而减弱，并且在许多情况下，胃石。