This study describes a new species, Gerochammina calloviensis nov. sp., from the D7 unit of the Dhruma Formation in central Saudi Arabia, which represents the first Jurassic record of the agglutinated foraminiferal genus Gerochammina . It is recovered from lithified rhythmic limestone–marl alternations of the Atash Member and the lower part of the Hisyan Member of the Dhruma Formation, which represents a middle Callovian shallow-marine epeiric carbonate ramp. The species occurs abundantly in fine-grained marly beds in the middle section of the Atash Member, interpreted in earlier studies as maximum-flooding deposits, and shows low recovery in the overlying Hisyan Member. The middle Callovian occurrence of Gerochammina calloviensis nov. sp. in the Dhruma Formation extends the stratigraphic range of the genus from the Cretaceous into the Jurassic and its paleoenvironmental range from deep-marine flysch to neritic carbonate ramps, providing a reference within the sequence-stratigraphic framework of the Dhruma Formation. Application of the acetic-acid disaggregation technique to well-indurated carbonates demonstrates that Jurassic shallow-marine successions can preserve delicate agglutinated taxa. This method may reveal further records of “deep-water” agglutinated forms in other Tethyan and Boreal carbonate platforms.