Abstract Bioerosional structures and encrusters on a total of 349 bivalves and 209 gastropod shells were studied from Al-Khobar coastline along the Arabian Gulf, Saudi Arabia. Nine ichnospecies belonging to five ichnogenera were identified, namely: Entobia geometrica, Entobia isp., Oichnus paraboloides, Oichnus simplex, Gastrochaenolites dijugus, Gastrochaenolites isp., Caulostrepsis taeniola and Maeandropolydora isp. Barnacles, serpulids, bryozoans and bivalves were recoded as encrusters on the internal and external surfaces of the investigated seashells. The studied bioerosional structures were defined as Gastrochaenolites-dominated ichnoassemblage, which is composed of Gastrochaenolites, Oichnus and borings of polychaete annelids and clionid sponges. It reflects marine conditions, in a shallow water depth and low rates of sedimentation. A postmortem colonization has been confirmed on the basis of the presence of different encrusters on the internal surfaces of many seashells, while those on the external surfaces indicated a colonization process mostly took place during the lifetime of the seashells.

中文翻译：

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来自沙特阿拉伯 Al-Khobar 海岸线的潮间带贝壳的 Gastrochaenolites 地相

摘要 研究了沙特阿拉伯阿拉伯湾 Al-Khobar 海岸线的 349 只双壳类动物和 209 只腹足动物壳的生物侵蚀结构和外壳。确定了属于五种鱼属的九种鱼种，即：几何昆虫纲、昆虫纲昆虫纲、抛物线纲昆虫纲、单纯石斑纲、Gastrochaenolites dijugus、Gastrochaenolites isp.、Caulostrepsis taeniola 和 Maeandropolydora isp。藤壶、蛇科动物、苔藓动物和双壳类动物被重新编码为所研究贝壳内外表面的外壳。所研究的生物侵蚀结构被定义为以 Gastrochaenolites 为主的 ichnosemblage，由 Gastrochaenolites、Oichnus 和多毛类环节动物和 clionid 海绵的钻孔组成。它反映了浅水深度和低沉积率的海洋条件。