Ceolodiscus is an extinct genus of gastropod from the Lower and Middle Jurassic of Europe, mostly on Germany, France and United Kingdom.
[1][2][3] Other posible records include specimens from Hungary of Earliest Jurassic (Hettangian) age.
[7] This genus is linked with the Toarcian Oceanic Anoxic Event, that likely triggered its evolution.
Whorls are generally smooth, evenly rounded and slightly overlapping; umbilicus deep, aperture ovate.
[1] Is the oldest known holoplanktonic gastropod, thanks to a bilateral symmetrical shells as an adaption to active swimming.