A primary study of bioerosional structures and skeletobionts associated with an almost monotypic assemblage of free-lying bryozoan colonies of Celleporaria? sp., from the middle Miocene succession of the Siwa Oasis, Egypt, revealed four groups of encrusters (serpulids, sheet-like cheilostome bryozoans, balanoid barnacles and oysters) and eight different ichnotaxa. Undersides of the colonies have basal exterior walls, which are relatively richer in encrusters than are the convex sides. The dominant bioerosional structures were due to the boring activities of non-predatory organisms. The diversity of macro-bioerosional ichnotaxa is moderate and includes Trypanites, Gastrochaenolites, Maeandropolydora, Caulostrepsis, Renichnus, Spirolites and Centrichnus. In addition, some conical borings perpendicularly penetrating the shells could belong to the predatory tracemakers of Oichnus. Despite a moderate total ichnodiversity, the observed sample diversity of ichnofossils is low (about 35% of the total specimens studied). This is explained by a relatively high sedimentation rate with only short periods of exposure on the seafloor. The dome-shaped bryozoan occurrence is interpreted to represent a parautochthonous assemblage, which may have been influenced by shallow-water processes in response to storm activity.

中文翻译：

---

埃及西部沙漠北部锡瓦绿洲中中新世的一种口吻苔藓虫的古生态学和埋藏学

对与 Celleporaria 的自由躺着的苔藓虫菌落几乎单一的组合相关的生物侵蚀结构和骨骼生物的初步研究？sp.，来自埃及锡瓦绿洲的中新世演替，揭示了四组结壳（serpulids，片状cheilostome bryozoans，龟头藤壶和牡蛎）和八种不同的ichnotaxa。菌落的下面有基部外壁，与凸面相比，它们的结壳相对丰富。主要的生物侵蚀结构是由于非捕食性生物的无聊活动。宏观生物侵蚀性 ichnotaxa 的多样性是中等的，包括锥虫、胃孔虫、Maandropolydora、Caulostrepsis、Renichnus、Spirolites和Centrichnus。此外，一些垂直穿透贝壳的锥形钻孔可能属于Oichnus的掠食性示踪剂。尽管总体化石多样性适中，但观察到的化石化石样本多样性较低（约占研究样本总数的 35%）。这可以通过相对较高的沉降率来解释，而在海底只有很短的暴露时间。圆顶状苔藓虫的出现被解释为代表了一个近地生物群落，这可能受到了响应风暴活动的浅水过程的影响。