DataSheet1_Investigating Mazon Creek fossil plants using computed tomography and microphotography.zip

More than 20,000 siderite concretions from the Mazon Creek area of northern Illinois, United States are housed in the paleobotanical collections of the Field Museum. A large proportion contain fossil plants of Middle Pennsylvanian age that often have excellent three-dimensional morphology and sometimes anatomical detail. Approximately eighty plant taxa have been recognized from the Mazon Creek Lagerstätte, but few have been studied in detail, and in some cases the systematic affinities of these fossils need reevaluation. The three-dimensional (3D) preservation of Mazon Creek fossil plants makes them ideal candidates for study using x-ray micro-computed tomography (μCT), and here we apply these techniques to more accurately reconstruct the morphology of specimens of Tetraphyllostrobus Gao et Zodrow and Crossotheca Zeiller. The mineralogical composition of the fossil plant preservation was studied using elemental maps and Raman spectroscopy. In-situ spores were studied with differential interference contrast, Airyscan confocal super-resolution microscopy, and scanning electron microscopy, which reveal different features of the spores with different degrees of clarity. Our analyses show that μCT can provide excellent detail on the three-dimensional structure of Mazon Creek plant fossils, with the nature of associated mineralization sometimes enhancing and sometimes obscuring critical information. Results provide guidance for selecting and prioritizing fossil plant specimens preserved in siderite concretions for future research.

美国伊利诺伊州北部马兹恩克里克地区的超过20,000个菱铁矿球粒，被妥善保存在菲尔德博物馆的古植物学藏品中。其中，大量球粒含有中生代彭宁世时期的植物化石，这些化石往往具有出色的三维形态，有时甚至能够呈现出细微的解剖结构。截至目前，已从马兹恩克里克层位中识别出大约八十种植物类群，然而其中仅有少数被深入研究，在某些情况下，这些化石的系统发育关系也需重新评估。马兹恩克里克植物化石的三维保存特性，使其成为利用X射线微计算机断层扫描（μCT）技术研究的理想对象。在本研究中，我们应用了这些技术，以更精确地重建Tetraphyllostrobus Gao et Zodrow和Crossotheca Zeiller化石标本的形态。通过元素图谱和拉曼光谱分析，研究了化石植物的矿物学组成。利用差分干涉对比、Airyscan共聚焦超分辨率显微镜和扫描电子显微镜等技术，对原位孢子进行了研究，这些技术以不同清晰度揭示了孢子的不同特征。我们的分析表明，μCT能够为马兹恩克里克植物化石的三维结构提供详尽的细节，而与之相关的矿化性质有时会增强，有时则会掩盖关键信息。研究结果为未来研究选择和优先考虑菱铁矿球粒中保存的化石植物标本提供了指导。