Kentrosaurus was smaller than Stegosaurus. While Stegosaurus had an predictable length of 7.4 m and a weight of 3,500 kg, Kentrosaurus was just 2.5 meters long and had a much lesser weight (although no accurate estimates can yet be made) — certainly small for a stegosaur. Kentrosaurus armour is also rather dissimilar from that of Stegosaurus. Stegosaurus, of course, bore a sequence of plates along its spine. Kentrosaurus, on the other hand, had small plates along its neck and shoulders. Along the rest of the back and down the tail were more than a few — typically seven — stunning pairs of imposing spikes, each up to a foot in length. Like other stegosaurs, such as the European Lexovisosaurus, it had one more pair of spikes jutting backwards from the hips. Unlike Stegosaurus, which may have used its plates for thermoregulation, the spines of Kentrosaurus might only have served once purpose: self-defense. Kentrosaurus also differed from Stegosaurus in one additional key feature — the pronounced spines on the backbone near the hip and tail region that characterize the vertebrae of a Stegosaurus were not present from Kentrosaurus. Therefore, Kentrosaurus might not rear up on its hind legs. Indeed, the length of the thigh bone compared with the rest of the leg indicates that Kentrosaurus was a sluggish and inactive dinosaur. Environment
The similarities and differences between Kentrosaurs and Stegosaurs exemplify well the geological principle of continental drift. The resemblance between the kentrosaur fossils found in Tendaguru, Tanzania and the stegosaur fossils establish in North America are evidence that these two points of the globe, now widely alienated, were once very close together and indeed part of super continent, known as Pangaea, and later the northern half, known as Laurasia. These two points must also have had very alike climactic conditions in order to have produced such similar specimens. Meanwhile, the differences between the animals exemplify the changes that their different ancestors underwent as the two groups of animals parted company. Discovery
The 1909–1912 German journeys to East Africa resulted in the discovery of several new dinosaur species, of which Kentrosaurus was one of the most significant for the reason outlined above — it implied a former nearness of Tanzania and the Morrison Formation, in the eastern part of the Rocky Mountains. Of the three paleontologists on this expedition, it was Edwin Henning who first described Kentrosaurus in 1915. An almost-complete skeleton was at one time improved and mounted in the Humboldt Museum of the University of Berlin, but the museum was bombed throughout World War II and most of the bones were lost.