In the reality surrounding us, only birds, insects and bats can fly, the sizes of which usually do not exceed one meter. Therefore, it can be difficult for us to imagine giant flying dinosaurs, the size of an antelope or giraffe, freely fluttering in the air. However, archaeological finds suggest that such animals really existed and lived for more than one million years.
Flying reptiles
Ancient flying dinosaurs, or pterosaurs, appeared in the Mesozoic era about 200 million years ago. It was so long ago that, despite all the efforts of scientists, it is not possible to solve all the secrets of their life even now. Researchers still can not say from which ancestors the lizards appeared, why they disappeared and how exactly they could fly, having sometimes incredible dimensions.
At the same time, it is known that these were the first vertebrate animals that managed to master the airspace of the planet. In terms of internal structure, they had much in common with birds, but externally resembled a mixture of birds and bats. Pterosaurs are often identified with dinosaurs, but this is a mistake. They represent two different groups of prehistoric creatures that belonged to a subclass of diapsid reptiles, or archosaurs. It included many animals, but only crocodiles have survived to this day. The last pterosaurs lived about a million years ago and disappeared from the face of the Earth during the Cretaceous – Paleogene extinction, along with dinosaurs and some marine reptiles.
Fly or swim?
The first pterosaur in history was discovered in 1784, but this event did not become a sensation, and the scale of the find was estimated only after almost 20 years. The fact is that fossils of an unknown fossil have been attributed to an aquatic creature. The Italian naturalist Cosimo Collini considered that the elongated forelimbs served him as flippers and helped him move to the sea. In taxonomy, he was assigned a place between birds and mammals.
At the beginning of the 19th century, the naturalists John German and Georges Cuvier suggested that the creature could fly. They decided that with long fingers of the forelimbs it supported the large wings, so the sample was called the pterodactyl, which literally translates as “wing + finger”. Thus, the pterodactyl found in Bavaria was the first official evidence of the existence of flying dinosaurs.
Species diversity
Since the beginning of the 19th century, about 200 genera of pterosaurs have been discovered, which are divided into two large suborders. The first and more primitive flying dinosaurs were ramforinhs. Their remains were found in Tanzania, Portugal, Germany, Great Britain, Kazakhstan and the countries of South America. The ramforinhs were much smaller in size than the later species, had a large head, a long tail and a short neck. They had narrow wings, and the jaw had well-developed teeth.
For a long time, ramforinhs coexisted with representatives of the second group - pterodactyls, but, unlike them, became extinct at the beginning of the Cretaceous. It is assumed that their disappearance occurred gradually and completely naturally. Pterodactyls appeared only in the Jurassic period and lived until the end of the Mesozoic era. Much more mysteries are connected with their extinction, because at that time 30% of all marine and land animals did not die on Earth.
Pterodactyls were rather large creatures with a large elongated head, wide wingspan, and a short tail. Compared to the early forms of pterosaurs, they had a more elongated and mobile neck, and most of the later species, in general, had no teeth.
Appearance
There have been many attempts in the print media and films to visualize pterosaurs, but all the images of the prehistoric flying dinosaurs remain very approximate. From the found remains it is known that they had beaks of various sizes and shapes resembling birds. The body of animals was covered with filiform hairs of pinofiber, the origin of which differs from the origin of the hair of mammals. Researcher Alexander Kellner suggested that they are more like shields on the body of crocodiles and feathers of birds.
On the head of many flying dinosaurs there were crests consisting of keratin and other relatively soft substances. They could reach quite large sizes and, most likely, served as the main distinguishing features between males and females. Perhaps they also performed the function of thermoregulation. They were peculiar outgrowths on the beak and head of the animal and could have the most bizarre forms.
In representatives of the genus thalassodromeus, the crest accounted for almost three quarters of the surface of the entire skull, which could reach 1.5 meters in length. In animals of the genus tapejar, the crest was bony and consisted of several teeth on the back of the head and at the base of the beak.
The wings of pterosaurs are skin membranes that attach to the fore and hind limbs. Inside the membranes were thin muscles, as well as blood vessels. Due to this structure, for a long time they were considered ancient bats and even ranked among mammals.
Dimensions
The pterosaur squad included creatures that were completely different in structure and size. It is believed that the early ramforinha did not exceed the size of modern birds. Some of them were no more than a tit, while they had developed and rather long wings. For example, the body of anurognates grew only 9-10 centimeters in length, but in the wingspan they reached almost 50 centimeters. The smallest of the lizards discovered by archaeologists was Nemicolopterus with a wingspan of 25 centimeters. True, it is likely that this is a cub, and not the adult form of a separate species of pterosaurs.
Over time, these animals became larger until they turned into real giants. Already in the middle of the Jurassic, flying dinosaurs reached 5-8 meters in wingspan, and weighed, presumably, about a hundred kilograms. The largest creatures of the Earth, capable of flying, to this day are considered quetzalcoatli and hatsegopteryks. They had relatively short bodies and strongly elongated necks, and in size they can be compared with adult giraffes. Their skulls could reach 2-3 meters in length, and the wingspan was about 10-11 meters.
Flying lizards and birds
The ability to actively fly and some features of the anatomy made pterosaurs the first contenders for the role of bird ancestors. Like the feathered, they possessed a keel, to which the muscles responsible for the wingspan were attached; their bones also had voids filled with air; and in later species, the thoracic vertebrae even fused to provide stiffer support for the wings.
Despite all these similarities, scientists believe that birds developed parallel to the lizards and most likely evolved from dinosaurs. There are dozens of finds of feathered reptiles, which theoretically could be their ancestors. This list includes: maniraptors, archeopteryx, protoavisi and others. Feathered close to modern species appeared only in the Jurassic period, at a time when pterosaurs were already in full use of airspace.
Millions of years old birds and flying lizards lived side by side. They led a similar lifestyle and competed for food. According to one hypothesis, it was the birds that caused the increase in the size of pterosaurs and the complete extinction of their small species.
Ways of transportation
Studies of pterosaur skulls showed that they had highly developed parts of the brain that were closely associated with flight. They accounted for 7-8% of the brain mass, while in modern birds they occupy only 2%. But flying was not the only way to travel. Lizards had well-developed limbs that allowed them to run fast and walk confidently on the ground. Many of them moved with all four legs, like mammals.
It is still unknown how exactly the pterosaurs flew. Today, the largest birds - the Andean condor and the wandering albatross - reach a maximum of 3 meters in wingspan and weigh no more than 15 kilograms. The pterosaurs were several times larger and it was unclear how, in general, they could fly into the air. According to one version, powerful hind limbs helped them take off, with which they repelled from the ground. According to another version, for the initial jerk, they strongly waved their heads to create resonance and set the rest of the body in motion.
