PMC

Grey section, material of Paranthodon, including partial premaxilla, maxilla and nasal. Stegosaurus skull is a reconstruction from Stegosaurus stenops USNM 4934 (United States National Museum) and DMNH 2818 (Denver Museum of Nature and Science).

Reconstructions of Stegosaurus stenops (NHMUK R36730) and associated convex hulls. (a,b) C_vol(min); (c,d) C_vol(pref); (e,f) C_vol(max); (g) C_vol(C&E). (Online version in colour.)

Analysis B3 and C2 use Huayangosaurus as stegosaurian exemplifier for analyses of and , respectively. Analysis B4 of uses Stegosaurus as stegosaurian exemplifier, and Analysis C3 of uses both Huayangosaurus and Stegosaurus. Paranthodon is found as a basal nodosaurid in B3, in a large polytomy in C2, as a basal thyreophoran in B4 and in a monophyletic Stegosauria in C3. Resolution of analyses increases when derived taxonomic exemplifiers are used.

Anterior semicircular canal (ASC) in (A) Psittacosaurus and (B) Stegosaurus scaled to equivalent relative head size using the allometric factor common to the two functional groups. Although the ASC in the small-bodied biped, Psittacosaurus, is absolutely smaller than in the larger quadruped, Stegosaurus, when the canal systems are scaled as seen here, it is shown that the biped has a markedly larger relative canal. Scale = 10 mm.