Gastroliths, where preserved, can provide indirect evidence regarding diet in extinct avian and non-avian dinosaurs. Masses of gastroliths consistent with the presence of a gastric mill are preserved in many Early Cretaceous Jehol birds mostly belonging to the Ornithuromorpha. Gastroliths are also present in basal birds Sapeornis and Jeholornis in which herbivory is supported by direct evidence these taxa consumed seeds in the form of crop or stomach contents. Although gastroliths have been correlated with herbivory in non-avian dinosaurs, the presence of gastroliths and bone together in Ambopteryx calls this association in to question. Despite being known from greater numbers of specimens than other avian lineages, no unequivocal direct or indirect evidence of diet has been recovered from Jehol deposits for the Enantiornithes. A referred specimen of Bohaiornis guoi IVPP V17963 was described as preserving a small number of gastroliths interpreted as rangle, gastroliths whose function is cleaning the stomach in extant raptorial birds. However, based on comparison with gastroliths in other Jehol birds, it has alternatively been suggested that the identified structures are not ingested stones at all but some unusual mineral precipitate. Considering the limited evidence regarding diet in Enantiornithes and the importance of accurately identifying the traces in Bohaiornis in order to understand the enantiornithine digestive system, we extracted two samples of these purported gastroliths and explored these traces using computerized laminography scanning, scanning electron microscopy, energy dispersive x-ray spectroscopy, ground sections, and body size to gastral mass regressions. Similar analyses were conducted on gastroliths extracted from undisputed gastral masses of two Jehol ornithuromorphs and the non-avian pennaraptoran Caudipteryx. The combined results contradict the hypothesis that these traces are gastroliths and supports the interpretation they are mineral precipitate, most likely authigenic quartz (chalcedony). Although authigenesis is commonly responsible for the preservation of soft tissues, it is unclear if these traces record part of the tissues of this Bohaiornis. This study highlights the importance of a multidisciplinary approach in understanding unusual traces in the fossil record and reveal a previously unidentified taphonomic phenomenon in fossils from Jehol deposits.

保存的胃石可以提供有关灭绝的鸟类和非鸟类恐龙饮食的间接证据。许多早期白垩纪热河鸟类都保留了与胃磨存在相符的胃石块，这些鸟类大多属于鸟嘴兽。胃鸟中也有胃astroSapeornis 和 耶洛洛尼斯在草食学上有直接证据支持，这些分类单元以作物或胃内容物形式消耗了种子。尽管在非禽类恐龙中胃石与食草有关，但在人类中，胃石和骨骼共同存在mb虫对此协会提出质疑。尽管从比其他鸟类谱系更多的标本中获知，但尚未从Enholornithes的热河矿床中找到明确的饮食直接或间接证据。参考标本Bohaiornis guoiIVPP V17963被描述为保留了少量的胃石，这些胃石被解释为残缺的胃石，其功能是清洁现存的猛禽的胃。但是，根据与其他热河鸟类的胃石比较，可以替代地表明，识别出的结构根本不是吞食石头，而是一些不寻常的矿物沉淀物。考虑到有关Enantiornithes中饮食的有限证据，以及准确识别食物中痕迹的重要性Bohaiornis为了了解对映鸟氨酸的消化系统，我们从这些声称的胃石中提取了两个样品，并使用计算机X射线断层扫描，扫描电子显微镜，能量色散X射线光谱，地面切片以及人体大小对胃部质量的回归进行了探索。从无争议的两种热河鸟形鸟和非禽类披萘烷中提取的胃石进行了类似的分析甲状旁腺。合并的结果与这些痕迹是胃石的假设相矛盾，并支持了它们是矿物沉淀物（最可能是自生石英（玉髓））的解释。尽管授权发生通常是软组织的保存原因，但尚不清楚这些痕迹是否记录了软组织的一部分。Bohaiornis。这项研究强调了多学科方法在理解化石记录中异常痕迹方面的重要性，并揭示了Jehol矿床化石中以前未发现的自发现象。