The word "dinosaur" comes from two Greek words. The first is deinos, which means "terrible", "powerful" or "wonderful". The second is sauros, which means lizard. We are constantly learning new facts about dinosaurs from their fossils. Over the years, we have accumulated many "facts" that have long been believed to be true, but have been refuted in the light of recent debate. Here are ten facts that have changed over time. Forget everything you knew about dinosaurs.
Dinosaurs threw eggs like lizards
In the past, the general consensus was that dinosaurs left their eggs like reptiles, but recent finds have shown that many dinosaurs tended their offspring like modern birds. The fossil remains of dinosaurs and their nests tell a lot about their behavior. Nests range from simple pits to complex mud rim designs. We met in large groups and one at a time. These nests and egg collections showed that dinosaurs were caring parents.
Many Maiasaurus nests have been found in Montana. Nests, eggs, brood, juveniles and adult dinosaurs, or rather their remains, were also found in the same area. Such a find indicates a high level of parental care and a high sociality of the dinosaur. The nests were holes dug in the ground, 2 meters wide and 1.1 meters deep. The newborns were only 30 centimeters long. The nests were 9 meters apart, the size of an adult Maiazaurus. At one location, a group of 40 nests covered 2.5 acres of land.
Dinosaurs were covered in scales
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We used to think that all dinosaurs were covered with scales, but recent finds have confirmed the existence of more than 30 species of feathered flightless dinosaurs, based on features such as fossils and feather bumps. Today all feathered dinosaurs - and this is confirmed - are the carnivorous ancestors of birds. But in 2013, the remains of a herbivorous dinosaur were found near the banks of the Olova River in Siberia. This new species, Kulindadromeus zabaikalicus, was feathered. Perhaps all dinosaurs had feathers.
K. zabaikalicus lived about 160 million years ago and was 3 meters long. Based on incomplete skeletons, of which many have been found, archaeologists have concluded that this bipedal animal had short front legs and long hind legs. It is likely that when the animal lived, a river flowed in its habitat. After death, the river protected the remains of the dinosaur from scavengers, thanks to which the imprints of feathers and scales were preserved.
Dinosaurs were cold-blooded
Many people believe that dinosaurs were cold-blooded like reptiles today, but then they would not have the muscles needed to hunt other dinosaurs. Scientists have measured the metabolism of many dinosaurs by determining the percentage of bone mass in the body and the rate of bone growth from the fossilized bone rings. The results showed that dinosaurs had growth and metabolic rates that were inherent in warm-blooded creatures, not cold-blooded ones.
Dinosaurs were not like mammals, birds, reptiles, or fish. Their physiology was different from modern animals. We thought dinosaurs were slow, clumsy, cold-blooded animals, but the more fossils are found, the more the dinosaurs become Velociraptor-like. Most likely, they were active warm-blooded mammals and birds.
But to say that all animals are cold-blooded or warm-blooded would be too easy. Some of the animals living today, like the great white shark, leatherback sea turtle and tuna, do not fit into a simple classification. Based on their growth and metabolic rates, dinosaurs were somewhere in between.
Pterosaurs were dinosaurs
We all know about pterosaurs. They became famous for "Earth Before Time" and "Jurassic Park", only now … they are not dinosaurs. These reptiles of the Mesozoic era were the first vertebrates to take off and form a separate group of animals. Dinosaurs are commonly used to refer to all antediluvian reptiles, but not all antediluvian reptiles were dinosaurs.
Dinosaurs belong to a very diverse group of terrestrial reptiles that have unique anatomical features. Pterosaurs were flying reptiles and are excluded for this reason. The main feature that set dinosaurs apart from other reptiles is their limbs. Unlike antediluvian crocodiles, dinosaur limbs were directly under their bodies and allowed them to stand up straight.
Brontosaurus doesn't exist
The first Brontosaurus was documented in the 1870s, but in 1903, paleontologists figured out that these fossils actually belonged to the Apatosaurus. In the 1970s, brontosaurus fossils were discovered in the western United States. The dinosaur was named Brontosaurus excelsus, "noble thunderbolt". But later, scientists decided that B. excelsus was such an apatosaur that they renamed it Apatosaurus excelsus.
More recently, a new analysis of fossils by the University of Oxford has restored Brontosaurus as a genus. This is made possible by modern computer programs that are used to calculate the differences between other species and genera of dinosaurs. It turned out that there are many differences between brontosaurus and apatosaurus.
Dinosaurs became extinct
Are the dinosaurs extinct? Not really. Sauropods and many other groups are truly extinct. But one of the eight large groups of dinosaurs, theropods, survived the Melpaleogene extinction. One of 40 subgroups of theropods survived and became familiar to all of us birds.
It is believed that all dinosaurs went extinct about 65 million years ago, but thousands of living dinosaur species still live on. According to modern evolutionary classification systems, there is no reason not to consider birds as a species of dinosaur.
Biologists divide dinosaurs into two large groups - lizard and bird. Lizard-like dinosaurs are divided into Sauropodomorpha, which includes long-necked dinosaurs, and Theropoda, which includes modern birds and bipedal dinosaurs such as Tyrannosaurus rex.
Velociraptors were large dinosaurs
Thanks to Jurassic Park, we all know Velociraptors, intelligent scaly dinosaurs who love to sneak up on frightened kids. It turns out that the dinosaurs in the movie weren't real Velociraptors (and neither were they). In paleontology, as in other sciences, names are constantly changing. Some dinosaurs are called differently by different scientists. Some are renamed. Most of the changes are known to specialists, but in one of the rare cases we call a dinosaur differently from paleontologists. The Velociraptors in Jurassic Park were completely wrong, and the experts knew it immediately.
Velociraptors were found in Mongolia in the 1920s. They were small predators that grew up to 0.5 meters in height and were about 1.8 meters in length. It was believed that they killed their victim with a sickle-shaped claw on their feet.
When above Jurassic Park, one type of raptor was known that matched the Velociraptor depicted in the film - the deinonychus. Deinonychus was found in the 1960s. It was believed to be an enlarged version of the Velociraptor, but their genera differed in many ways. They were twice as long and taller than their Mongolian cousins. They had a large sickle-shaped claw on each leg, long legs with prehensile hands, and a powerful tail that helped to maintain balance when chasing prey. A familiar picture, isn't it?
T-rexes are poorly seen
We all remember that “Don't move! He won't see us if we don't move from Jurassic Park. But Tyrannosaurus rex didn't have as bad eyesight as we thought. Even without going far, the first sign that T. rex had good vision is in the frontal setting of the eyes and narrow skull - it had a wonderful sense of depth. And each eye was the size of a tennis ball.
The binocular range of T. rex was found to be 55 degrees, which is greater than that of the hawk, so this supports the basic observations. In addition, other theropods had a binocular range comparable to modern birds of prey. Further research showed that T. rex had 13 times greater visual clarity than humans. A number of tests showed that T. rex could clearly see certain objects up to 6 kilometers away.
T. rex had useless pens
Many of us think T. rex had relatively small and useless pens, but this is not the case. Each of the "arms" was very muscular and could probably lift 200 kilograms. Evidence for this has been found in cracks in the forks (bones) of many Tyrannosaurus rex fossils. These cracks were probably the reason for the incredible fighting with other Tyrannosaurs.
T. rex could grab the victim's throat with its teeth and strangle it by holding it with its hands. And most likely, it was for hunting that the forelimbs of T. rex were used.
Plesiosaurs are dinosaurs too
We've all heard of the Loch Ness Monster, which is supposedly a plesiosaur. But what many do not know is that plesiosaurs were not dinosaurs. Dinosaurs belong to a vast group of terrestrial reptiles with unique anatomical features. Like pterosaurs, aquatic reptiles don't fit the bill.
The plesiosaurs had a wide body with a short tail and a length of 2.4 to 14 meters. They had long necks, small heads, and large flippers instead of legs. (Other genera of plesiosauroids had large heads and short necks.) The fins were used to turn quickly, but they floated slowly. Long necks allowed them to grab prey floating near the surface. Many images show plesiosaurs with their heads sticking out of the water, but they were not capable of this. Even if they could stretch their necks like that, gravity would most likely bend them.
ILYA KHEL