Univ. Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5276 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, F-69007 46 Allée d'Italie, Lyon, France.
Univ. Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5276 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, F-69007 46 Allée d'Italie, Lyon, France
Proc Biol Sci. 2018 Apr 11;285(1876). doi: 10.1098/rspb.2018.0197.
Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our dataset. This distinct taxonomic clustering in Ca isotope values observed between spinosaurids and other predators provides unambiguous evidence for niche partitioning at the top of the trophic chains: spinosaurids foraged on aquatic environments while abelisaurid and carcharodontosaurid theropods relied almost exclusively on terrestrial resources.
大型掠食者在北非白垩纪中期的恐龙组合中过度丰富。这种不平衡的生态系统结构涉及到典型的鲨齿龙类或鲨齿龙类兽脚亚目恐龙与具有争议性生态的长吻鳄形类恐龙同时存在。在这里，我们报告了来自尼日尔（加杜法瓦）和摩洛哥（凯姆凯姆地层）白垩纪中期组合牙齿珐琅质（表示为 Ca）中的钙（Ca）同位素值，以研究资源分配。在这两个组合中，鳄龙科恐龙都表现出明显的同位素特征，在我们的数据集是最负的。在 Ca 同位素值上观察到的鳄龙科恐龙与其他掠食者之间的这种明显的分类聚类为食物链顶端的生态位分化提供了明确的证据：鳄龙科恐龙以水生环境为食，而鲨齿龙类和鲨齿龙类兽脚亚目恐龙几乎完全依赖陆地资源。
