Growth, diet, thermophysiology and mobility of sauropods - Implications from bone isotope geochemistry for paleobiology and gigantism

骨骼和牙齿是脊椎动物个体生命史的宝贵档案。它们在其同位素组成中记录了有关生长、饮食、热生理和流动性以及气候和环境的信息。在这个项目中，每年气候、季节性和食物摄入量的时间序列将通过对生长增量的连续采样和对组织学和地球化学特征良好的蜥脚类长骨上的生物磷灰石的同位素分析来确定。记录的季节性氧同位素循环度将作为骨生长的年度时间标志。将计算所有主要蜥脚类分类群的定量生长曲线，这是理解蜥脚类巨型恐龙个体发育和系统发育进化的基础。将通过分析蜥脚类动物骨骼和牙齿以及潜在的现存和化石食物植物的碳同位素组成来研究使蜥脚类动物获得并维持其巨大体重的饮食和摄食策略。蜥脚类动物在从不同来源摄取食物和水的过程中的移动性将被同位素追踪。通过分析骨骼和蛋壳中的钙同位素，探讨产卵对现存和灭绝的始祖龙钙代谢的影响及其作为性别代用品的潜在应用。最后，我们将开发直接辐射测定化石骨骼的钚-氦同位素系统的适用性，以确定蜥脚类恐龙血统中巨人的进化。骨骼同位素地球化学将为研究蜥脚类恐龙的古生物学、古生态学和进化成功提供重要的新见解，蜥脚类恐龙是有史以来最大的陆地动物。

Bones and teeth are valuable archives of the life history of the individual vertebrate. They record in their isotopic composition information about the growth, diet, thermophysiology and mobility as well as climate and environment. In this project time-series of annual climate seasonality and dietary intake will be determined by serial sampling of growth increments and isotope analysis of the biogenic apatite on histologically and geochemically well-characterized sauropod long bones. The recorded seasonal oxygen isotope cyclicity will be used as annual time marker for (bone-) growth. Quantitative growth curves will be calculated for all major sauropod taxa and are fundamental for understanding the ontogenetic and phylogenetic evolution of sauropod gigantism. Diet and feeding strategies which enabled sauropods to attain and sustain their enormous body mass will be investigated by analyzing the carbon isotope composition of their bones and teeth as well as of potential extant and fossil food plants. Mobility of sauropods during food and water intake from different resources will be traced isotopically. The influence of laying eggs on the calcium metabolism of extant and extinct archosaurs and its potential use as gender proxy will be explored analyzing calcium isotopes of bones and eggshells. Finally the applicability of the lutetium-hafnium isotope system for direct radiometric dating of fossil bones will be developed to date the evolution of gigantism in the sauropod lineage. Bone isotope geochemistry will provide important new insights into the palaeobiology, palaeoecology, and evolutionary success of sauropod dinosaurs, the largest land animals ever.