Dinosaur fossils found in Tendaguru, Tanzania, and believed to date from the late Jurassic period, are suprisingly similar to fossils found in North America and from the same period. This is part of the evidence that these two points of the globe, now widely seperated, were once very close together and indeed part of one larger continent - Pangaea. These two points must also have had very similar climactic conditions in order to have produced such similar specimens.
Therefore, we find many species of dinosaur existed in similar but subtley different "flavours" in both North America and Africa. Kentrosaurus aethiopicus ("pointed lizard from Africa") was one such variant, a smaller African cousin to the more well-known Stegosaurus. While Stegosaurus has an estimated length of 7.4 metres and a weight of 3500kg, Kentrosaurus was just 2.5 metres long and had a much smaller weight (although no accurate estimates can yet be made) - certainly small for a stegosaur.
The 1909 - 1912 German expedition to East Africa resulted in the discovery of several new dinosaur species, of which Kentrosaurus was one of the most important for the reason outlined above - it implied a former proximity of Tanzania and the Morrison Formation, in the eastern part of the Rocky Mountains. Of the three paleontologists on this expedition, it was Edwin Hennig who first described Kentrosaurus in 1915. An almost-complete skeleton was at one time recovered and mounted in the Palaeontological Museum of Humboldt University, East Berlin, but the museum was bombed during World War II and most of the bones were lost.
It's armour was also rather different from that of Stegosaurus. Stegosaurus, of course, bore a series of plates along it's spine. Kentrosaurus, on the other hand, had small plates along it's neck and shoulders. Along the rest of the back and down the tail were several - typically seven - spectacular pairs of imposing spikes, each up to a foot in length. Like other stegosaurs, such as the European Lexovisoaurus, it had another pair of spikes jutting backwards from the hips. Unlike Stegosaurus, which may have used its plates for thermoregulation, the spines of Kentrosaurus could only have served once purpose - self-defence.
Kentrosaurus also differed from Stegosaurus in one other key feature - the pronounced spines on the backbone near the hip and tail region that characterise the vertebrae of a Stegosaurus were absent from Kentrosaurus. Therefore, Kentrosaurus could 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 slow and inactive dinosaur.