Kentrosaurus
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| Kentrosaurus
Conservation status: Fossil | ||||||||||||||
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K. aethiopicus (type) |
Kentrosaurus aethiopica ('pointed lizard from Africa') was a genus of dinosaur closely related to the better-known Stegosaurus. Its name means 'pointed lizard'. Kentrosaurs were African cousins of the North American Stegosaurus. They differed in size, in the shape of their armour plating, and in their bodily flexibility.
Description
Kentrosaurs were smaller than Stegosaurs. While Stegosaurus had an estimated length of 7.4 m and a weight of 3,500 kg, 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.
Kentrosaurus armour is also rather different from that of Stegosaurus. Stegosaurus, of course, bore a series 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 several — typically seven — spectacular pairs of imposing spikes, each up to a foot in length (see also: Thagomizer). Like other stegosaurs, such as the European Lexovisosaurus, 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.
Environment
The similiarities and differences between Kentrosaurs and Stegosaurs illustrate well the geological principle of continental drift. The similarity between the kentrosaur fossils found in Tendaguru, Tanzania, and the stegosaur fossils found in North America are evidence that these two points of the globe, now widely separated, were once very close together and indeed part of supercontinent, known as Pangaea, and later the northern half, known as Laurasia. These two points must also have had very similar climactic conditions in order to have produced such similar specimens. Meanwhile, the differences between the animals illustrate the changes that their different ancestors underwent as the two groups of animals parted company.
Discovery
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 Humboldt Museum of the University of Berlin, but the museum was bombed during World War II and most of the bones were lost.