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

骨骼和牙齿是个体脊椎动物生命史的宝贵档案。它们在同位素成分中记录了有关生长、饮食、热生理学和流动性以及气候和环境的信息。在该项目中，年度气候季节性和饮食摄入量的时间序列将通过生长增量的连续采样和对组织学和地球化学上已明确表征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周期将用作（骨）生长的年度时间标记。将计算所有主要蜥脚类动物类群的数量生长曲线，这对于理解蜥脚类巨型动物的个体发生和系统发育进化至关重要。通过分析蜥脚类恐龙的骨骼和牙齿以及潜在的现存和化石食用植物的碳同位素组成，将研究使蜥脚类恐龙获得并维持其巨大体重的饮食和喂养策略。蜥脚类恐龙从不同资源摄取食物和水时的活动性将通过同位素进行追踪。通过分析骨骼和蛋壳的钙同位素，探讨产卵对现存和灭绝主龙钙代谢的影响及其作为性别指标的潜在用途。最后，将开发镥铪同位素系统对化石骨骼进行直接放射性测年的适用性，以确定蜥脚类恐龙谱系中巨人症的进化。骨同位素地球化学将为古生物学、古生态学和蜥脚类恐龙（有史以来最大的陆地动物）的进化成功提供重要的新见解。

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.