Dinosaurs are a group of weird dinosaurs. Their heads are hemispherical and their feet are like bird's claws. 19 In the 1950s, dinosaur tooth fossils were first discovered, but scientists were not sure what they were. Later, in 1924, people found the skull and skeleton of a stegosaurus. Stegosaurus is a kind of herbivorous dinosaur, small in size, walking on two hind legs, similar to ornithopod dinosaur. But unlike ornithopods, its head is very strong and as safe as a helmet. Therefore, it is classified as pachycephalosaurus.

The swelling of the head

Why does Houdanlong have such a thick skull? Pacitasaurus is one of the largest dinosaurs in Pacitasaurus. As a dinosaur, the thickness of the whole skull of pachycephalosaurus is normal, but its skull is 22 cm thick. The edge of the round head of Houdanlong is also surrounded by a round raised joint. In order to compete for the opposite sex, male swollen-headed dinosaurs may have a discussion duel-head-butting competition. In the competition, the thicker the skull, the easier it is for the male dinosaur to win.

Bone shed

There is a prominent bone shed at the back of the skull of pachycephalosaurus, which is about 25 cm thick and looks like a bowling ball. Paleontologists speculate that this is the place where Houdanlong collided, but the collision site here is very small, which is prone to danger, especially the lateral sprain of the neck. In addition, when pachycephalosaurus collided with each other, this kind of bone shed may bring the annual shock caused by the collision to the whole body through nerves, thus avoiding head injuries. This feature is also manifested in other pachycephalosaurus, such as Flat-headed Dragon and Styx Dragon. However, the thickness of their bone shed is different.

The bones of Houdanlong

People don't know much about the neck bone of stegosaurus. Scientists believe that these bones must be particularly strong, because only in this way can they withstand the impact of the head collision in the catching bucket.

Styx, relatives of blackheads.

The Styx fossil was discovered in Hell Creek, Montana, USA on 1983. It is speculated that this Styx is about 2.4 meters long. Styx is a mysterious dinosaur with well-developed bony processes on its head, back and nose. In all the fossil records, countless exquisite and complicated headdresses of Styx make it the most beautiful and ferocious dinosaur and even all dinosaurs. The unusually thick skull shows that the column dragon is a more advanced species in the thick jaw class, because its skull plate has developed to a thicker direction, which is the evolutionary direction of the thick jaw class. So far, only five Styx skulls and some fragmentary remains have been found.

The head of an inflated dragon

When Houdanlong hit his head and ran forward at the speed of horse racing, his spine was straight. Because its head is hemispherical, the impact force in the middle of the head is the strongest when it hits. In a competition in which two dinosaurs with thick-headed dragons collided in the middle of their heads, their heads could only face their bodies. The head shape of pachysaurus was different. Some, such as the head shape of Houdanlong, are completely round; Others, such as the flat-headed dragon, have a flat head and gradually tilt upward to form a pointed head. All thick-headed dinosaurs had joints and sharp horns in their snouts. At the edge of their thick heads, there are also such nodules and sharp corners. The edge of this head is very similar to the edge of the neck shield on the head of Ceratosaurus. This situation means that these two kinds of dinosaurs are probably close relatives. Scientists suspect that dinosaurs will find a "bang" when they hit their heads, so the huge impact sound must be heard far away.

Dinosaur business card

Name: Pacitasaurus, period: end of Cretaceous, shape: 4.6m, weight 1.5t, genus: Pacitasaurus, distribution: North America: USA.