Stegosaurus (lat. Stegosaurus “roof lizard”) a genus of late Jurassic herbivorous dinosaurs that existed 155-145 million. years ago (Kimmeridgian). It includes three types. Thanks to the spikes on the tail and the bone plates on the back, they are one of the most recognizable dinosaurs.
This is the most famous representative of stegosaurids (stegosaurids) a family of dinosaurs, the distinguishing feature of which was the rows of bone plates and spikes located along the back. These animals lived since the Middle Jurassic and became extinct by the beginning of the Late Cretaceous.
However, in western North America, stegosaurs are found only in Late Jurassic deposits. These are large herbivorous dinosaurs that lived in the neighborhood and sometimes became the prey of other famous North American dinosaurs: allosaurs and ceratosaurus.
The body of the stegosaurus was covered with numerous small bone outgrowths, located even in the throat area. However, the most characteristic feature is the presence of large plates and spikes. Located along the spine, the plates have a different size. The largest plates are located in the pelvis. In large stegosaurs, the plates could reach 1 m in height. Two pairs of tail spines could reach up to 6 cm in length.
Despite their size, the dorsal plates were thin and fragile and could not provide a good defense against predator attacks. The heavy structure of the legs of the stegosaurus, their strange backward curvature and the large size of the animal itself indicate that he could not escape.
Stegosaurs’ only defense against the brutal, carnivorous therapods that lived in their immediate vicinity was the tail. Armed with spikes, this powerful tail could move from side to side with a large amplitude, which posed a serious danger to the unprotected paws, abdomen and inguinal region of predators.
Scientists hypothesize that stegosaurus’ back plates worked as a device to regulate its body temperature. A network of fine grooves along the surface of the plates indicates the presence of numerous blood vessels. They could heat up or remove excess heat, depending on the state of the animal’s body, the position of the sun and the ambient temperature. Most likely, stegosaurs could regulate the flow and amount of blood passing through the plates in order to prevent overheating or hypothermia of the body.
Stegosaurus armatus (Stegosaurus armatus) was discovered for the first time. Marching in 1877 north of Morrison, Colorado. The name was composed by Marsh from the Greek. στ]γος (roof) and σαρος (lizard), since the paleontologist considered that the plates lay on the back of the dinosaur and formed a kind of gable roof. At first, many types of stegosaurs were described, which were subsequently combined into three.
Marsh believed that the stegosaurus moved only on two legs, since the forelimbs were significantly shorter than the hind limbs. However, already in 1891, having assessed the physique of a dinosaur, he changed his mind.
Stegosaurus had a brain the size of a walnut; however, thanks to the bone plates, he could perfectly control his body temperature and defend himself. Most of the time the Stegosaurus was forced to spend looking out for any of the many ferocious predators on the horizon. But at the slightest opportunity, this dinosaur protected by plates used its toothless beak and ate nearby vegetation.
The skeletal remains of a Stegosaurus are easily distinguishable due to the impressive row of plates running along the entire back of this animal. These plates served as good armor, protecting, at least to a certain extent, from predators such as the terrible Allosaurus. The tail was equipped with spikes and thus could be used for effective side impacts.
But these plates were useful even when there were no predators nearby. If in the early Jurassic morning, when the temperature was probably low enough, the Stegosaurus turned sideways to the sun, so that the sun’s rays fell on the wide sides of the plates, its entire body gradually warmed up.
At noon, however, it could get too hot. Then this animal could turn so that the plates do not absorb so much heat.
In many ways, this heating system is similar to solar-absorbing solar panels found in some modern homes. The scientists also found signs on the plates that there may have been blood vessels inside them. At first, some scientists even claimed that these plates could change their position, so that the Stegosaurus could lower them horizontally. But today this theory does not find much support.
Stegosaurus armatus is the first discovered species, known from two incomplete skeletons, two skulls and separate bones from at least 30 individuals. Had 4 spikes on the tail and relatively small plates, reached a length of 9 meters.
Stegosaurus stenops described by Marsh in 1887 from fossils from Colorado. Found a complete skeleton of a representative of the species and about 50 fragmentary. Was less than S. armatus, reaching only 7 meters, but had larger plates.
Stegosaurus longispinus described by Charles Gilmour from one incomplete skeleton from Wyoming. Also reached 7 meters, but had the longest spikes. Some researchers refer to the genus Kentrosaurus.
The only Stegosaurus skeleton in the Russian Federation found in Jurassic deposits (170-165 million. years ago) of a coal mine in the Sharypovsky district of the Krasnoyarsk Territory, exhibited in the Krasnoyarsk Museum of Local Lore.