so it was most likely a simple passage. The maxilla is roughly triangular, as in most other thyreophorans. The tooth row is horizontal in lateral view, and in ventral view it is sinuous. Stegosaurus and Huayangosaurus possess a straight tooth row in ventral view, although Scelidosaurus and Jiangjunosaurus do not. The maxilla of Paranthodon preserves the tooth row, and shows that there is little to no overhang. This differs from ankylosaurians, where there is a large overhang of the maxilla. As with Stegosaurus and Silvisaurus, there is a diastema (gap in the tooth row) on the maxilla in front of the tooth row. The posterior maxilla is incomplete so no information is known about the jugal or lacrimal contact. Paranthodon has an elongate, dorsally convex nasal, like in most other stegosaurs. There are thickened ridges along the sides of the nasals. The preserved portion of the nasal does not contact the premaxilla or maxilla. Thirteen teeth are preserved in Paranthodon, but as they extend to the back of the maxilla there were possibly more in life. The teeth are symmetrical as in stegosaurs except Chungkingosaurus. Along the base of the tooth crown there is a swelling (cingulum), which is seen in all other known stegosaurid teeth except Huayangosaurus. The teeth have a middle ridge, with five fewer prominent ridges on either side. This is similar to the size ridges seen on Kentrosaurus. Like all stegosaurians, the denticles on the teeth are rounded at the tips, in contrast to ankylosaurians. Also, like Huayangosaurus, but unlike Kentrosaurus and Stegosaurus, Paranthodon possesses a prominent buccal margination (a ridge beside the tooth row). Paranthodon teeth preserve wear, but wear is absent on most teeth, similar to Huayangosaurus, meaning it is likely that Paranthodon lacked occlusion between teeth. As only two fragments of a vertebra are known, few anatomical details can be observed. The right transverse process and prezygapophysis are preserved. The vertebra is possibly a middle dorsal, based on the angle of the transverse process and the orientation of the prezygapophysis. Similar to Stegosaurus and Chungkingosaurus mid-dorsals, the transverse process is angled about 60º dorsally. Unlike in all other stegosaurs except Stegosaurus, the prezygapophysis faces dorsally. Classification Currently, Paranthodon is classified as a stegosaur related to Stegosaurus, Tuojiangosaurus, and Loricatosaurus. Initially, when Broom assigned the name Palaeoscincus africanus to the Paranthodon fossils, he classified them as an ankylosaurian. This classification was later changed by