Tylodicoceras is a genus of the Koninckioceratidae (Cephalopoda, Nautiloid) from the Devonian through Mississippian of North America with a large, slightly involute, discoidal shell that is rounded laterally and concave ventrally. Their sides bear a single row with large rounded nodes.
References
Bernhard Kummerl. 1964, Nautiloidea-Nautilida. Treatise on Invertebrate Paleontology Part K. Geological Society of America and University of Kansas Press.