Millions of years ago, our planet was dominated by giant lizards. It is possible that they would be here still, if not for one coincidence — the Chicxulub asteroid that fell on the surface of our planet 65 million years ago. It was he, according to recent studies, was the cause of death of these prehistoric monsters. But who else besides dinosaurs lived on the Earth nearly 200 million years ago? After the asteroid all the dinosaurs became extinct, but life on the planet is still here. Let’s meet the amazing animals that shared the planet with the giant lizards.
When and how people learned about the existence of dinosaurs?
For the first time an ancient extinct lizard was described by scientists in 1824. Found the remains of nine-meter length has been found in the beginning of 1818 near the town of Woodstock in the UK. In 1841, the English paleontologist Richard Owen have collected and summarized all known at that time information on fossil reptiles. He called them “dinosaurs”, which translated from Greek means “terrible lizard”.
Soon after, in 1843, in sandy sediments of the geological plates in Connecticut (USA), paleontologists have discovered traces of freakishly large birds. In comparison with this discovery, the elephant’s leg seemed miniature. Since the researchers did not give rest question about what size it had to be a bird that made these tracks. The answer, as we know today, is that these footprints belonged to, not the bird. In the Mesozoic era the history of our planet since the Jurassic period (about 200 million years ago) until the end of the Cretaceous period (about 70 million years ago), the Earth was inhabited by “terrible lizard”. Some of them, like a kangaroo, ran on its hind legs, and the traces left by them are strongly reminiscent of traces of modern birds.
It turns out, millions of years ago dinosaurs owned the land, sea and air. A variety of reptiles inhabited the pine and fern forests of the Earth. Some flew between the trees, spread its leathery wings, while others, like the size of chickens, ran across the meadow, and in the marshes lived a huge and very slow dinosaurs brahiozavry. By the way, the world’s largest skeleton of a Brachiosaurus is located in the geological-palaeontological Museum of the University of Berlin. The bones of this giant were discovered at Tendaguru mountain in Africa. Tall Brachiosaurus reached 11,87 m, width — 22 m, and weighed no less than 50 thousand kg. However, the biggest and most intimidating, as we know today, was Tyrannosaurus Rex. This predator lived on the territory of modern USA and Canada. At length the monster reached 10 meters, and the height five. His meter-long jaws were armed with hundreds of sharp and large teeth. If t-Rex existed today, it could easily carry a Rhino in its mouth.
But if the land, the sky and the sea were in the power of the dinosaurs, and, more importantly, when lived mammals? According to a study published in the journal Science, the first mammals were running around the surface of our planet with the dinosaurs. The researchers believe that after the terrible lizards died out, all the other animals came out of the shadows.
What mammals lived with dinosaurs?
Two scientific articles tell us about the individual mammals that were the size of modern hamsters. Fossils of these extinct relatives are known to us mammals were discovered in China and analyzed by an international team from the University of Chicago (USA) and Museum of natural history, Beijing (China). Having carefully studied the shape of the bones a paleontologist zhe-XI Luo from the American University and his colleagues came to the conclusion that Agrodolce and Locofocos coexisted with dinosaurs 160 million years ago.
These animals superficially resembled modern mole and squirrel. Locofocos dwelt under the earth, as evidenced by his short, broad fingers with two phalanges, similar to small blades. But the spine of this 9 centimeter mammal seems particularly suitable for underground movements. The agrodolce was approximately 14 cm in length and dwelled among the trees. Judging by the structure of the limbs and spine, agrodolce was perfectly adapted to climbing trees. Researchers believe that he was frequently down to earth, as it probably fed on sage. The following conclusions can be drawn from the structure of the teeth of the animalthat was able to pierce the stems of plants. In addition, the researchers emphasize that in the anatomy of both animals showed signs that coincide with the action of genes identified in modern mammals. It is therefore possible that these genetic cocktails were so evolutionarily advantageous that survived to our days.
The researchers said that the remains indicate that mammals existed in the Jurassic period. Out, little by little, we learn that in the shadow of the dinosaurs lived and other animals.
But tiny docotor and agrodolce was not the only mammals that lived during the age of the terrible lizards. As the newspaper writes Sciencemag, more than 150 million years ago there was a well-known Australian echidna and platypus. They represent a transitional link between reptiles and other mammals. The Australian echidna is oviparous mammals, which, to put it mildly, not quite normal. First Australian echidna was described in 1792 by the zoologist George Shaw, who a few years later and described the platypus. However, due to the long trunk of the animal Show first decided that the Australian echidna is a relative of the anteater. Only 10 years later, the anatomist Edward home found in the echidna and platypus common feature is the cloaca into which open the bowel, ureters and reproductive tract. On the basis of this feature in the future, has been allocated squad a single pass.
However, one of the most astonishing discoveries took place in the summer of 2000, when a team of researchers led by Timothy Rowe of the University of Texas at Austin, stumbled upon the fossil bones scattered among the rocks of the Kayenta formation in Northern Arizona. Initially found the remains was not surprised paleontologists. Only 9 years later, the expert to prepare the fossil for study, noticed something surprising: the remains were tiny teeth and jaw bone with a length of just 1 inch. Later, scientists determined that the remains belonged to Scientarium — an animalthat lived on Earth about 185 million years ago. Adult Scientarium the size of a large cat, so it could be mistaken for mammal, if not a large jaw bone, large teeth and lack of ears. Scientarium is cynodont, a member of the group that occurred mammals.
Subsequently, the researchers extracted from the rock, the remains of the babies first mammals or their relatives from the Jurassic period, and not one, but 38. Thus, the finding becomes one of the most momentous in decades. Scientarium, according to researchers, provides important information about what characteristics define mammals as well as what features were present in their earlier relatives. Skeleton Scientarium much like the skeleton of a mammal and at the same time in the skeleton of reptiles. The remains of the young suggests that unlike mammals, who spend more time on the upbringing of offspring, they were able to fend for themselves thanks to well-developed bones and teeth.
Due to these findings, scientists can learn more about the evolution of mammals. The fossils discovered in different parts of the world refuted the belief that mammals of the dinosaur era were small, unremarkable insectivores that lived in the shadow of the giant reptiles.
Who lived on the planet after the death of the dinosaurs?
The death of the dinosaurs was good news for mammals, whose number increased significantly immediately after the event. So, according to a study published in the journal Nature , the behavior of mammals has rapidly changed since our first furry ancestors gradually began to come out of hiding not only at night but also in daytime. It is possible that this factor could have an impact on the evolution of Homo Sapiens.
Paleontologists and evolutionary biologists have long believed that the ancestors of modern mammals were nocturnal animals. The fact that most mammals can see well in low light. They also developed sense of smell and hearing and still have whiskers (e.g. whiskers of cats) that allow them to feel what is right in front of them — all these qualities are incredibly useful in the dark. Similarly, when mammals began to go out during the day, it was a mystery, because behavior is difficult to distinguish from fossils. Scientists rely on the shape of the eye sockets and nasal cavities, to determine which senses were important to the extinct animal, but these clues can mislead. However, to understand exactly when our ancient ancestors changed nocturnal n day, the scientists examined daytime and nighttime habits of more than 2415 species of living mammals, and then used genetic data to build pedigrees, noting that the Earth could appear very early day ancestors.
According to a study published in the journal Nature Ecology and Evolution, the first appearance of the ancestors who were active in the daytime, probably lived roughly 65.8 million years ago — just 200,000 years after the mass extinction that wiped out the dinosaurs, except for birds. For example, the common ancestor of modern camels, hippos and deer probably moved on with night life on the daily around the same time. Today camels are active during the day, while the hippos are active at night, and deer observed mixed way of life. Overall, the researchers concluded that the daily activity of animals begins the moment that the dinosaurs disappeared. The reason for this, obviously, is the fact that to go out during the day was too risky.