ABSTRACT: The Karakaya Complex in northern Turkey is classically subdivided into two units (Upper and Lower Karakaya Complex) and located in the Sakarya Composite Terrane. The Upper Karakaya Complex includes different blocks and tectonic slices within a Triassic matrix. A new genus of miliolid foraminifera (Cornuspiroidea, Neodiscidae) is established from the late Capitanian (latest Guadalupian) neritic limestone block from the Upper Karakaya Complex. The new genus Globidiscus is characterized by a large, inflated lenticular in the axial and subglobular in transverse section and involute test with well-developed flosculinisation and a porcelaneous wall with buttresses. It was probably derived from the Praeneodiscus-Neodiscus lineage in late Capitanian (Guadalupian).