Middle Miocene tonnoidean gastropods from near Wonosari, Yogyakarta, Java, Indonesia

A well preserved tonnoidean gastropod fauna is described from Wonosari, Gunung Kidul Regency, Special Region of Yogyakarta, Java, Indonesia. In Bursidae, the second Indo-Pacific species of Aquitanobursa is described. In Cassidae, new species of Cassis and Cypraecassis are described, as well as the oldest known member of the genus Casmaria, and the first complete adult specimens of Phalium menkrawitense Beets, 1941 are recorded. In Cymatiidae, species represented are Cymatiella fennemai (Martin, 1899), Monoplex rembangense (Wanner & Hahn, 1935), a most unusual new species of Monoplex, and Gyrineum bituberculare (Lamarck, 1816). In Personidae, specimens assigned to Distorsio dunggranganensis (Martin, 1916) are the first adults of the species, and confirm distinction from the living species D. habei Lewis, 1972. In Tonnidae, two small (20 mm high) specimens of a Malea species with narrow spiral cords are assigned to M. papuana (Beets, 1943), the first record from Java.