Pushing the limits of bioapatite clumped isotope analysis: resolving endo- from ectothermy in mosasaurs

突破生物磷灰石聚集同位素分析的极限：解决沧龙的内变温问题

• 批准号: 426291434
• 负责人: Professor Dr. Jens Fiebig
• 金额: --
• 依托单位: Fachrichtung Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426291434?language=en
• 关键词: Pushing; limits; bioapatite; clumped; isotope

We have recently demonstrated that the clumped isotopic composition of teeth of modern vertebrates is exclusively controlled by temperature. As such, the bioapatite clumped isotope thermometer may have the potential to resolve endo- from ectothermy in extinct vertebrates. However, an application of this new thermometer to small and medium sized extinct vertebrates is currently limited by the relatively large sample size (250-1250mg) of unaltered tooth enamel(oid) required for such analysis. Here, we request funding to significantly reduce this sample size by a factor of 15-20. We then aim at applying this new analytical setup to teeth from mosasaurs and contemporaneously deposited carbonate-bearing phases to clarify whether these marine reptiles were endo- or ectotherms. Their widespread abundance in the world’s ocean of the Upper Cretaceous allows to investigate if body temperatures varies with paleolatitude (40°N to 65°S) and body size or occurs decoupled from these parameters. Both mosasaur teeth and contemporaneously deposited carbonates and fish teeth will be intensively screened by an array of state-of-the-art analytical techniques to identify which parts of these samples were affected by diagenesis. Taken together, these systematic investigations are fundamental for an exploration of the potential of the bioapatite clumped isotope thermometer for the reconstruction of thermophysiology of small and medium sized extinct vertebrates.

我们最近证明，现代脊椎动物牙齿的聚集同位素组成完全受温度控制。因此，生物磷灰石团块同位素温度计可能有可能解决灭绝脊椎动物的内变温问题。然而，这种新型温度计在中小型灭绝脊椎动物中的应用目前受到此类分析所需的相对较大的未改变牙釉质样本量（250-1250mg）的限制。在此，我们请求资金将样本量大幅减少 15-20 倍。然后，我们的目标是将这种新的分析装置应用于沧龙的牙齿和同时沉积的碳酸盐相，以澄清这些海洋爬行动物是恒温动物还是变温动物。它们在上白垩纪世界海洋中的广泛存在使得我们能够研究它们的体温是否随古纬度（北纬 40° 至南 65°）和体型的变化而变化，或者与这些参数脱钩。沧龙的牙齿以及同时沉积的碳酸盐和鱼牙都将通过一系列最先进的分析技术进行深入筛选，以确定这些样本的哪些部分受到成岩作用的影响。总而言之，这些系统研究对于探索生物磷灰石团块同位素温度计重建中小型灭绝脊椎动物热生理学的潜力至关重要。