It possessed features of both stegosaurs and ankylosaurs. Likewise there is no evidence of insulation in the stegosaurs. The latter is believed to have been the ancestor of all stegosaurs and ankylosaurs. The teeth are symmetrical as in stegosaurs except "Chungkingosaurus". Unlike in all other stegosaurs except "Stegosaurus", the prezygapophysis faces dorsally. The sacro-lumbar expansion is not unique to stegosaurs, nor even sauropods. They had small, triangular teeth that were loosely packed, similar to stegosaurs. These included the well-preserved skeletons of two stegosaurs, an armor-plated dinosaur. Like all stegosaurs, "Chungkingosaurus" was a herbivore. Most stegosaurs, but not "Stegosaurus", also have a spine over each shoulder. "Paranthodon" has an elongate, dorsally convex nasal, like in most other stegosaurs. "Wuerhosaurus", probably the last of the stegosaurs, lived during this time. Armored dinosaurs that weren't stegosaurs were unknown in the formation until the 1990s. Well known stegosaurs are "Stegosaurus" and "Kentrosaurus". Thyreophora is characterized by body armor and includes stegosaurs, ankylosaurs, "Scelidosaurus", and "Scutellosaurus".