About Kentrosaurus
| Scientific Name (Genus) | Kentrosaurus |
| Meaning of Name |
Spiked lizard
kentron (spike, sharp point) [Greek] - sauros (lizard) [Greek] |
| Classification | Ornithischia, Thyreophora (Thyreophoroidea, Stegosauria, Stegosauridae) |
| Total Length | Approx. 4.0 - 5.5m (Weight estimated 700 - 1,600kg) |
| Diet | Herbivorous |
| Period | Late Jurassic (approx. 154.8 to 145 million years ago) |
| Sub-classification / Species Name | Kentrosaurus aethiopicus (Type species) |
| Year of Paper Publication | 1915 |
| Genus Name Publication |
Kentrosaurus aethiopicus, der Stegosauride des Tendaguru.
Sitzungsberichte der Gesellschaft naturforschender Freunde zu Berlin. by Edwin Hennig. 1915. |
Characteristics and Combat Style
Kentrosaurus is a medium-sized stegosaur that lived in Africa (present-day Tanzania) during the Late Jurassic period. Because of its small size, it was once thought to be a "primitive stegosaur", but recent detailed research has revealed that it is a highly evolved species belonging to the Stegosauridae family.
by Gemini.
On its back, relatively small bone plates are lined up from the neck to the middle. Because these plates have a small area, it is thought that they were not used to regulate body temperature like Stegosaurus, but mainly for visual display, such as appealing to or intimidating peers.
Its greatest defensive weapons are a pair of long spikes protruding sideways from its shoulders (parascapular spines) and the spikes at the tip of its tail. Because Kentrosaurus had a muscular, heavy tail, its center of gravity was extremely far back (around the front of the hips), and the weight on its forelimbs was only about 10-15% of the total.
When attacked by predators such as carnivorous dinosaurs, it could open its lightly burdened forelimbs wide to lower its posture, and swing its flexible tail, which could bend in a range of about 180 degrees, like a whip. It is estimated that this powerful blow was forceful enough to inflict fatal wounds even on large carnivorous dinosaurs like Allosaurus.
Taking advantage of its center of gravity being in the back, Kentrosaurus could also take a standing posture, supporting its body with its hind legs and sturdy tail. This allowed it to eat not only ferns on the ground but also plants at a height of about 3 meters, and it seems to have successfully shared food with giant sauropods and small dinosaurs.
Sexual Dimorphism and Herd Life
From the Kentrosaurus excavation site (Tendaguru Formation), up to 70 individual fossils have been found closely packed together. This indicates that they did not act alone but lived in large herds.
A detailed study on the shape of the femur (thigh bone) published in 2011 revealed that the bones are clearly divided into two patterns: a "robust shape" and a "gracile shape". Furthermore, since the ratio of excavated fossils was 1 "robust type" to 2 "gracile types", this is thought to indicate a difference between males and females (sexual dimorphism) rather than a difference in growth.
From the ratios of modern animal herds, it is highly likely that the less numerous "robust type" was male. This "1 to 2" ratio became an important discovery in dinosaur research, showing that Kentrosaurus had a "polygynous" social structure where a few strong males surrounded many females.
Fast Growth and Secrets of the Jaw
Once, armored dinosaurs like stegosaurs were thought to grow very slowly. However, examining the microscopic structure of fossilized bones revealed that Kentrosaurus produced bone at a faster pace than the large Stegosaurus, growing rapidly. It is thought that they needed to quickly enlarge their bodies to protect themselves from carnivorous dinosaurs in the harsh environment of Tendaguru.
Also, Kentrosaurus had a very small head relative to its body, but its jaw joint was an efficient structure that cleverly used the "principle of leverage," giving it a strong bite force. It seems they also used swallowed stones (gastroliths) in their stomachs to grind and thoroughly digest the hard plants of the Jurassic period.
History of Discovery and Naming Troubles
Source: Kentrosaurus aethiopicus, der Stegosauride des Tendaguru. Sitzungsberichte der Gesellschaft naturforschender Freunde zu Berlin. by Edwin Hennig. 1915.
Many fossils were discovered in Tanzania, East Africa, by a large-scale German expedition conducted from 1909 to 1912. In 1915, paleontologist Edwin Hennig named it "Kentrosaurus" as a new genus and species, but a minor uproar occurred immediately after.
The year after naming it, Hennig realized there was a ceratopsian in North America with a similar name, "Centrosaurus". Fearing that just a different initial "C" and "K" would make it the same name and he might lose priority, he hastily tried to change the name to "Kentrurosaurus". Today, the rule is established that even a single-letter difference in spelling makes a name valid as a separate name, so it has reverted to the original Kentrosaurus.
The fact that Stegosaurus found in North America and Kentrosaurus in Africa belong to closely related genera suggests that they had a common ancestor during the era of the supercontinent Pangea, when the continents were one, and that each evolved on the split continents.
Unfortunately, most of the valuable type specimens (holotype specimens) were destroyed in the bombing of Berlin, Germany, during World War II in 1943. The skeleton seen in Berlin today is a combination of unburned parts, replicas, and bones from other individuals.