Bioerosive structures in the cortical region of a vertebra from a mosasaur fall in the López de Bertodano Formation (Upper Maastrichtian) in Seymour Island (Isla Marambio), Antarctica, are reported. The traces studied are similar but not coincident with the described microborings in other fossil bone remains. The morphology and extension of these bioerosive structures are considered as the result of the activity of endolithic organisms on the original vascular channels of the bone. They are approximately straight, anastomosed, and commonly filled with an opaque mineral and framboidal pyrite. As most of the bone structure is well preserved, only the small portion of the cortical region was exposed to the microorganisms’ activity. This would mean that the mosasaur individual died well earlier than the burial event. This is their first report of this type of bioerosive structures in a mosasaur fall.

中文翻译：

---

南极洲晚白垩世沧龙的生物侵蚀结构

据报道，南极洲西摩岛（马兰比奥岛）的 López de Bertodano 组（上马斯特里赫特）的沧龙坠落的椎骨皮质区域的生物侵蚀结构。研究的痕迹与其他化石骨骼遗骸中描述的微孔相似但不相符。这些生物侵蚀结构的形态和延伸被认为是内石生物对骨骼原始血管通道的活动的结果。它们几乎是直的、吻合的，并且通常充满不透明的矿物和菱形黄铁矿。由于大部分骨骼结构保存完好，只有一小部分皮质区域暴露于微生物的活动中。这意味着沧龙个体早于埋葬事件死亡。