Herein, 20 ichnospecies belonging to 8 ichnogenera were identified in bivalves, gastropods, and corals (n = 701) from the Late Pleistocene coral reef along the Red Sea coast, northwest Saudi Arabia. The trace fossils were produced by clionid sponges (), endolithic bivalves (), polychaete annelids (), vermetid gastropods (), and acrothoracican barnacles (). The habitat conditions changed gradually, from well-oxygenated, shallow, high-energy back-reef and reef crest bioeroding polychaetes and bivalves, to deep, low-energy reef slope dominated by boring sponges. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 22-37 http earth TÜBİTAK Research Article doi yer-2005-7 Bioerosional structures from the Late Pleistocene coral reef Red Sea coast northwest Saudi Arabia 1 2 3 2 Huriye DEMİRCAN Abdelbaset S. EL-SOROGY Talal ALHARBI 1 Department of Geological Research General Directorate of Mineral Research and Exploration MTA Ankara Turkey 2 Geology and Geophysics Department College of Science King Saud University Saudi Arabia 3 Geology Department Faculty of Science Zagazig University Zagazig Egypt Received Accepted Published Online Final Version Abstract Herein 20 ichnospecies belonging to 8 ichnogenera were identified in bivalves gastropods and corals n 701 from the Late Pleistocene coral reef along the Red Sea coast northwest Saudi Arabia. The trace fossils were produced by clionid sponges endolithic bivalves polychaete annelids vermetid gastropods and acrothoracican barnacles . The recognized ichnotaxa were Entobia geometrica E. ovula E. cf. goniodes E. cf. retiformis E. cretacea Entobia isp. Gastrochaenolites torpedo G. lapidicus G. cf. dijugus Gastrochaenolites isp. Oichnus paraboloides O. simplex Oichnus isp. Caulostrepsis taeniola Caulostrepsis isp. Maeandropolydora cf. sulcans Maeandropolydora isp. Renichnus isp. Centrichnus isp. and cf. Rogerella isp. Most bivalves and gastropods contain Entobia rather than Gastrochaenolites which is commonly found in the larger and thicker corals. The content of the trace fossils indicated an Entobia ichnofacies formed in the coral reef during transgression. The habitat conditions changed gradually from well-oxygenated shallow high-energy back-reef and reef crest bioeroding polychaetes and bivalves to deep low-energy reef slope dominated by boring sponges. Keywords Bioerosional structures coral reefs Pleistocene Red Sea coast Saudi Arabia 1. Introduction of micro and macroborers in .
