Ancolioceras opalinoides (Mayer 1864)

8.5cm. Together with the bivalves Myophorella cf. formosa (right) and Entolium demissum (left). From the Wutach Valley. Sinon Bank, Murchisonae Zone, Upper Aalenian. These were assigned to the genus Staufenia by Rieber in 1963, but Dietze, Rieber etal have revised the genera in December 2014 to the above.