Identification, structure and occurrence of fossil melanin pigments

近年来，许多研究塑造了我们对化石黑色素色素的认识，包括对海洋爬行动物和恐龙等化石生物颜色的有争议的重建。然而，只有很少的研究包括可靠的基于质谱的化石黑色素分析化学调查。该项目最初将开发一种特定而敏感的质谱方法，用于证明化石样本中的真黑素和异黑素，从而可以检测稀有化石生物小样本中的色素。除了脊椎动物化石外，无脊椎动物化石将首次被系统地分析，迄今为止，对其黑色素的化学分析很少。此外，将基于微冷冻探针核磁共振波谱（NMR）和固态核磁共振（NMR）对化石黑色素进行结构分析。该项目的重要目标是澄清文献中讨论的几种黑色素化石是否实际上可以根据化学特征识别为黑色素，以及来自生物体不同部位（如眼睛、皮肤、毛发、羽毛或原羽毛）的黑色素化石如何彼此不同。总的来说，这项研究将为复杂大分子的化石记录提供基本的见解，并为评估古颜色重建提供坚实的基础。

In recent years, numerous studies have shaped our knowledge about fossil melanin pigments including controversially discussed reconstructions of the colours of fossil organisms such as marine reptiles and dinosaurs. However, only very few studies include reliable analytical chemical investigations of fossil melanins based on mass spectrometry. The project will initially develop a specific and sensitive mass spectrometric method for the proof of eumelanin and pheomelanin in fossil samples, allowing detection of the pigments in small samples of rare fossil organisms. In addition to fossil vertebrates, for the first time, fossil invertebrates will be systematically analyzed for whose melanins very few chemical analyses exist to date. In addition, a structural analysis of fossil melanins based on microcryoprobe nuclear magnetic resonance spectroscopy (NMR) and solid state NMR will be carried out. Important objectives of the project are to clarify if several fossil melanins discussed in the literature in fact can be identified as melanins based on a chemical characterization and how fossil melanins from various parts of the organisms like eyes, skin, hairs, feathers or protofeathers differ from each other. Overall, the investigation should provide fundamental insights into the fossil record of complex macromolecules as well as a solid basis for the evaluation of paleo-colour reconstructions.