Several other species which were assigned to "Styracosaurus" have since been assigned to other genera. "S. sphenocerus", described by Edward Drinker Cope in 1890 as a species of "Monoclonius" and based on a nasal bone with a broken "Styracosaurus"-like straight nose horn, was attributed to "Styracosaurus" in 1915. "S. makeli", mentioned informally by amateur paleontologists Stephen and Sylvia Czerkas in 1990 in a caption to an illustration, is an early name for "Einiosaurus". "S. borealis" is an early informal name for "S. parksi".