The chemical composition of fossil soft tissues is a potentially powerful and yet underutilized tool for elucidating the affinity of problematic fossil organisms. In some cases, it has proven difficult to assign a problematic fossil even to the invertebrates or vertebrates (more generally chordates) based on often incompletely preserved morphology alone, and chemical composition may help to resolve such questions. Here, we use in situ Raman microspectroscopy to investigate the chemistry of a diverse array of invertebrate and vertebrate fossils from the Pennsylvanian Mazon Creek Lagerstätte of Illinois, and we generate a ChemoSpace through principal component analysis (PCA) of the in situ Raman spectra. Invertebrate soft tissues characterized by chitin (polysaccharide) fossilization products and vertebrate soft tissues characterized by protein fossilization products plot in completely separate, non‐overlapping regions of the ChemoSpace, demonstrating the utility of certain soft tissue molecular signatures as biomarkers for the original soft tissue composition of fossil organisms. The controversial problematicum Tullimonstrum, known as the Tully Monster, groups with the vertebrates, providing strong evidence of a vertebrate rather than invertebrate affinity.

中文翻译：

---

软组织的化学特征将伊利诺伊州石炭纪的马宗溪Lagerstätte与脊椎动物和无脊椎动物区分开。

化石软组织的化学成分是用于阐明有问题的化石生物的亲和力的潜在强大工具，但尚未得到充分利用。在某些情况下，事实证明，仅根据通常不完全保存的形态就很难将有问题的化石分配给无脊椎动物或脊椎动物（通常是脊索动物），化学成分可能有助于解决这些问题。在这里，我们使用原位拉曼光谱技术研究了来自伊利诺伊州宾夕法尼亚州Mazon CreekLagerstätte的各种无脊椎动物和脊椎动物化石的化学，并且我们通过原位拉曼光谱的主成分分析（PCA）生成了化学空间。以甲壳质（多糖）化石产物为特征的无脊椎动物软组织和以蛋白质化石产物为特征的脊椎动物软组织分布在ChemoSpace的完全独立的，不重叠的区域中，从而证明某些软组织分子标记作为原始软组织组成的生物标志物的用途化石生物。有争议的问题Tullimonstrum（称为塔利怪兽）与脊椎动物一起，提供了脊椎动物而不是无脊椎动物亲和力的有力证据。