Calcareous benthic foraminifera from the Middle Upper Eocene Rashrashiyah Formation, Saudi Arabia: Part 1 – Miliolida and Lagenida

The Eocene Rashrashiyah Formation of northwestern Saudi Arabia consists predominantly of alternating marls and limestones deposited in an outer-shelf to upper-bathyal setting along the southern margin of the Tethys. The foraminiferal assemblage is diverse and includes planktonic, agglutinated benthic, and calcareous benthic components with generally good preservation. In this study, calcareous benthic foraminifera belonging to the suborders Miliolina and Lagenina are systematically documented from three measured sections (Outcrops A, B, and C). A total of 29 genera and 89 species are identified from 353 samples, including 3 genera of Miliolida and 26 genera of Lagenida, many of which are recorded for the first time from the Eocene of Saudi Arabia. The studied interval is assigned to planktonic foraminiferal Zones E13–E14 (Bartonian–Priabonian), providing a basis for regional correlation within the Arabian Plate. This contribution represents the first part of a comprehensive study of calcareous benthic foraminifera from the Rashrashiyah Formation, complementing previously published agglutinated assemblages and contributing to a more integrated taxonomic and paleoecological understanding of the succession.