The wing membrane structure that supported pterodactyl flight was completely different from that of vertebrates, birds and bats that could fly later. Pterosaur formed the wing surface by skin membrane, and the membrane composed of skin, muscle and other soft tissues extended from the chest to the extremely long fourth finger. Support the membrane with other phalanges. Pterosaur's membrane only attached to a slender finger (the fourth finger), extending backward to the knee along the side; There is also a membrane between the neck and the arm. The first three phalanges are claw-like slender hooks. Its membrane seems to be completely adapted to flying and gliding, but it is not as flexible and fragile as bat's membrane or bird's wings. Strong body, slender hind legs, its structure shows that it is not suitable for vertical movement or rest, and it hangs on its hind legs when resting. When flying, the neck seems to be upright, at right angles to the head and forward. The skull is light and strong, and most bones are fused together; Having a slender mouth; The eyes are very big. Like many birds, the eyeballs are reinforced by a series of bone plates (scleral rings) located on its four walls.
Based on fossils, a three-dimensional image of pterodactyl brain was established by using computerized tomography. The image shows that the cerebellar lobe of pterodactyl is quite developed, and its mass accounts for 7.5% of the brain mass, which is the highest proportion among known vertebrates. In contrast, the cerebellar lobe of birds who are good at flying only accounts for 1% to 2% of their brain mass.
The largest pterosaur is Fengshen Pterosaur (Fengshen Pterosaur). The length of the deployed wing is11~15m, which is equivalent to the size of an airplane. The smallest arboreal pterodactyl fossil, the pterodactyl Youlin, has a wingspan of only 25 cm, which is about the size of a swallow.
Pterosaur is a very special reptile with unique skeletal structure characteristics.
Pterosaur's forelimbs were highly degraded, and the fourth finger was elongated and thickened to become the flying wing finger. It consists of four phalanges and has no claws at the front. Together with the forelimbs, it forms a solid leading edge of the flying wing, supporting and connecting the membrane between the body side and the hind limbs, forming a flying wing membrane similar to the bird wing. The pterodactyl wrist developed a unique pterygoid bone, which extended forward to the shoulder and played a supporting role in the pterygoid membrane. The length of the first to third fingers becomes a hook claw outside the wing membrane, and the fifth finger degenerates and disappears.
Although living in the same era as dinosaurs, pterosaurs were not dinosaurs; They form a unique branch of the phylogenetic tree. Pterosaurs are reptiles flying in the blue sky, and sometimes they are mistaken for "flying dinosaurs". Pterosaur originated in the late Triassic about 2,654.38+0.5 million years ago and died out at the end of Cretaceous 65 million years ago. When dinosaurs ruled the landing site, pterosaurs controlled the sky.
Up to now, more than 120 species of pterosaur fossils have been found and named in the world.
The individual size and shape of pterodactyl vary greatly, such as the pterodactyl fossils found in Texas in the 1970s. Its wings spread about 16 meters, its width is about10.5 meters longer than that of the F- 16 fighter, and it is as small as a sparrow. There are two kinds of pterosaurs. Early beaked dinosaurs were primitive, mainly living in Jurassic, with long tails. Late pterosaurs mainly lived in Cretaceous, and their tails were short or even disappeared.
A relatively complete fossil "Ningcheng Jehol Pterosaur" was found in the late Mesozoic strata in China. The fossil skeleton is well preserved, and the wing membrane, fur derivatives and flippers all over the body are clearly preserved. The discovery of this fossil has enabled paleontologists to have a comprehensive understanding of the structure, distribution and morphological characteristics of pterosaur hair, and suggested that pterosaur hair and the original feathers of hairy dinosaurs may be homologous.