"Styracosaurus" is known from a higher position in the formation (relating specifically to its own genus) than the closely related "Centrosaurus", suggesting that "Styracosaurus" displaced "Centrosaurus" as the environment changed over time and/or dimension. It has been suggested that "Styracosaurus albertensis" is a direct descendant of "Centrosaurus" ("C. apertus" or "C. nasicornis"), and that it in turn evolved directly into the slightly later species "Rubeosaurus ovatus". Subtle changes can be traced in the arrangement of the horns through this lineage, leading from "Rubeosaurus" to "Einiosaurus", to "Achelousaurus" and "Pachyrhinosaurus". However, the lineage may not be a simple, straight line, as a pachyrhinosaur-like species has been reported from the same time and place as "Styracosaurus albertensis".