Neutron tomography, fluorescence and transmitted light microscopy reveal new insect damage, fungi and plant organ associations in the Late Cretaceous floras of Sweden

Neutron tomographic reconstructions, macrophotography, transmitted light microscopy and fluorescence microscopy are employed to assess the quality of organic preservation, determine organ associations, identify insect damage, and document fungal interactions with selected Santonian–lower Campanian plant fossils from the northern Kristianstad Basin, southern Sweden. Fricia nathorstii (Conwentz) comb. nov., is proposed for a composite fossil comprising an anatomically preserved (permineralized) cupressacean conifer cone and its subtending, concealed, leafy axis (preserved as a mould) in the Ryedal Sandstone. Several other impressions of conifer and angiosperm leaf-bearing axes and isolated leaves are described under open nomenclature. Three cuticle types are described from the non-marine plant-bearing beds in the basal part of the succession exposed at Åsen, but these are only assigned to informal morphotypes pending a comprehensive review of the extensive fossil cuticle flora. Two species of ascomycote epiphyllous fungi from Åsen are established: Stomiopeltites ivoeensis sp. nov. (Micropeltidales) and Meliolinites scanicus sp. nov. (Meliolales). The latter provides an important calibration point for dating the divergence of Meliolales, being the first pre-Cenozoic representative of the order. Various additional fungal remains, including thyriothecia, scolecospores, chlamydospores, putative germlings, and hyphae, are described from the cuticular surfaces of conifer and angiosperm leaves from Åsen. Insect herbivory is expressed in the form of both margin-feeding and piercing-and-sucking damage on angiosperm leaves. The Santonian–early Campanian vegetation is inferred to have grown in strongly humid, mid-latitude, coastal plain settings based on the depositional context of the assemblages, leaf morphology, and the pervasive distribution of epiphyllous fungi.

利用中子断层扫描重建、宏观摄影、透射光显微镜和荧光显微镜技术，本研究对瑞典北部克里斯蒂安斯塔德盆地的桑托尼亚阶至下坎帕尼亚阶植物化石的有机保存质量进行了评估，确定了器官的关联性，识别了昆虫的损害，并记录了真菌与所选植物化石之间的相互作用。新组合命名了弗里西亚纳托斯提（Conwentz）组合，它包括一个解剖学上保存的（次生矿化的）柏科松果及其下承托的隐蔽的叶轴（以铸模形式保存）的复合化石，发现于莱达尔砂岩。此外，对其他松科和被子植物叶轴以及孤立叶片的印痕进行了描述，并采用开放命名法。在 Åsen 层序底部非海洋植物化石层中描述了三种表皮类型，但这些类型仅被分配到非正式形态类型，待对广泛的化石表皮植物群进行全面审查。在 Åsen 建立了两种子囊菌亚门附叶真菌：Stomiopeltites ivoeensis 新种（Micropeltidales）和 Meliolinites scanicus 新种（Meliolales）。后者为 Meliolales 分支的年代提供了重要的校准点，是中生代以前该目第一个代表。此外，还描述了来自 Åsen 松科和被子植物叶片表皮的各种真菌残留物，包括杯状壳、丝孢、厚垣孢、可能的菌丝体和菌丝。在被子植物叶片上，昆虫食草性表现为边缘取食和刺吸损害。根据沉积环境、叶片形态和附叶真菌的广泛分布，推断桑托尼亚阶至早坎帕尼亚阶植被生长在强湿润、中纬度、海岸平原环境中。