Their fossil range's extent into the late Early Cretaceous exceeds that of other stegosaurs, such as huayangosaurids, which had died out by the end of the Late Jurassic. They are characterized by rows of osteoderms along the top of their neck, trunk and tail which graded with varying abruptness from the anterior plates to the caudal spines at a point posterior to the dorsal vertebrae. These may have had a number of functions: display and/or thermoregulation for the broad flat osteoderms, defense for the spikes.