Idoceras is a genus of perisphictacean ammonite, belonging to the Perisphinctidae subfamily Idoceratinae.[2] The genus is known from the Upper Jurassic, with a widespread distribution. Shells of Idoceras are evolute, with a wide umbilicus; ribbing strong, bifurcate high on flanks. Suture simpler than in the similar Ataxioceras.
Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press. p. L323.