tail vertebrae, the tops of the neural spines are rounded instead of bifurcated. The front edge of the shoulderblade is indented instead of running parallel to the rear edge. The front blade of the ilium diverges strongly sideways instead of weakly. The rear blade of the ilium has a knob-shaped expansion at the rear end. The front end of the prepubic process has an upward expansion. The plates of the hip and tail base are oval and low instead of high and triangular. The various published descriptions of Hesperosaurus contradict each other because of changes and differences in interpretation. Originally, Carpenter reconstructed the disarticulated skull elements into a very convex head, modelling it on the shape of Huayangosaurus. The discrepancies in the vertebral count are caused by applying different criteria to the problem whether (and which) cervicodorsal vertebrae should be considered part of the neck or the back. The exact shape of the plates is hard to determine due to erosion. Paul considered the neck plates to be low, but the back plates as taller. Also the Aathal specimens are as yet undescribed. A complete description of the entire material is in preparation by Octávio Mateus. The number of maxillary teeth were twenty per side, lower than the number with Stegosaurus. Carpenter described them as similar to the teeth of Stegosaurus, though somewhat larger. Peter Malcolm Galton in 2007 established some differences: there are rough vertical ridges present on the upper part of the crown, one per denticle; the fine grooves on the tooth surface are weakly developed. Osteoderms and skin impressions Carpenter in 2001 identified ten plates as part of the holotype. He described them as long and low. Asymmetrical bases would indicate that they ran in two rows. The end of the tail bore a "thagomizer" of two pairs of spikes, the front pair being thicker, the rear pair thinner and more horizontally directed to behind. In 2012, an histological study concluded that these osteoderms, skin ossifications, of Hesperosaurus are essentially identical in structure to those of Stegosaurus. CAT-scans showed that the plates have thin but dense outer walls, filled with thick spongy bone. The bone shows signs of having been remodelled during a metaplastic growth process. Extensive long and wide arterial canals were visible. The spikes have thicker walls and the hollows in the spongy interior are smaller. A single large blood vessel ran along the longitudinal