 Paranthodon was a small stegosaurid relative to larger relatives such as Stegosaurus . Thomas R. Holtz Jr. estimated that the animal was 5 @.@ 0 m ( 16 @.@ 4 ft ) long and weighed between 454 and 907 kg ( 1 @,@ 001 and 2 @,@ 000 lb ) . The snout is elongated , though not extremely so , and convex on top . The back of the premaxilla is long and broad , and the external nares are large . The teeth have a prominent primary ridge . The <unk> nasal and <unk> bones are relatively complete , and an incomplete premaxilla is also preserved . The partial snout resembles Stegosaurus in its large posterior premaxillary process and the extension of the palate . However , Stegosaurus is the only stegosaurid known from adequate cranial material to compare with Paranthodon , and even though their resemblance is great , tooth morphology is very distinguishing among the stegosaurians . For example , cranial material is only known from Stegosaurus , Paranthodon , Kentrosaurus , and Tuojiangosaurus , and in all of them , the tooth morphology differs . 
